Birdwatching in Suburban China

Early this year I spent time in China, specifically in Zigong, Sichuan Province. I was there for day-job reasons (acting as consultant for life-sized dinosaur models), but when not working I went and looked at giant pandas, and at the many amazing skeletons of Jurassic dinosaurs (and other fossil vertebrates) at Zigong Dinosaur Museum. I also did a fair bit of birdwatching, both in the various gardens and green spaces I could get to it but also in the urban and suburban places within easy distance of my accommodation. And I saw a bunch of stuff, which is what I want to talk about here.

Caption: come on - everybody loves White-browed laughingthrushes Pterorhinus sannio! More on this species below. Image: Darren Naish.

First things first. To identify the birds of a given region, you need a goddam field guide. Thinking it would be easy and simple to get a ‘Field Guide to the Birds of China’ before setting off, I went to buy one (I recall looking in Foyles in London’s Charig Cross Road, since it has an excellent field guide section) buuut…. nope. Nothing. After looking around online a bit I discovered John MacKinnon* and Karen Phillipps’s 2000 A Field Guide to the Birds of China. Which is great apart from the fact that it costs over £40, and usually over £50, which is above what I consider affordable for books. Goddammit. On this occasion, however, my luck was in since a special sale at NHBS meant that I was able to get it at half price (albeit not until long after my trip had happened).

* Yes, of Saola fame and so, so much else.

Caption: MacKinnon & Phillipps (2000), A Field Guide to the Birds of China. It’s not the most attractive field guide out there, but it does seem to be the best one. Image: Darren Naish.

Regular TetZoo readers might have heard me complain about book prices before. Books are horrendously over-priced, a thing I can’t help but feel angry about given that – as someone who’s spent most of their life in relative poverty – it bothers me a lot that knowledge is so frequently locked away unless you’re lucky enough to be able to afford access to it. Anyway, I digress.

Caption: feral pigeons and Whooper swans in China. Discussed below. Images: Darren Naish.

I should say that this was my first ever trip to China, and that I’d been told (no offence intended to Chinese friends and colleagues) to expect to see nothing in the way of wild animal life in view of relevant environmental issues. While I certainly saw places where pollution was bad and natural spaces were being destroyed or degraded, the good news is that I still saw a fair amount of wildlife – though, birds only. I should also add that the avifauna was – to my western European eyes – an interesting mix of the familiar and commonplace with the obscure and exotic. Aaaaand I should also add that my photos are mostly terrible. The skies were leaden grey and the lighting terrible during my entire time in China, plus birds are fast and my camera is not that great. So, apologies.

Caption: rallids and grebes of China. At top left: Common coot Fulica atra. At top right: Common moorhen Gallinula chloropus. Below: Little grebe Tachybaptus ruficollis. Image: Darren Naish.

Anyway, to business. What did I see? We’ll start with the larger birds. While at the ornamental lake at Chengdu Panda Base (or, more formally: Chengdu Research Base of Giant Panda Breeding), I saw Whooper swan Cygnus cygnus, Ruddy shelduck Tadorna ferruginea, Common coot Fulica atra, Common moorhen Gallinula chloropus and Little grebe Tachybaptus ruficollis. Coots, moorhens and Little grebes are birds I see regularly here in the UK, but more interesting were the several small raptors circling nearby. I’m not totally sure what they were and my photos are poor, but the small-headed look, extensive barring, dark primaries and lack of transverse bars on the tail make me think that this is either a Buteo or Butastur hawk or a baza. There are several accipiters in Sichuan but I don’t think that’s what we’re seeing here. Thoughts?

Caption: small, broad-winged raptor… of some sort. Image: Darren Naish.

Feral pigeons Columba livia were a thing, which isn’t a surprise but is still something you might need confirming. Then there’s this pigeon…

Caption: what is this pigeon… or dove, if you want? Read on. Both photos show the same individual, photographed at Chengdu Panda Base. Image: Darren Naish.

It’s a mid-sized, long-tailed, mostly brown, grey-headed, red-legged pigeon that I saw walking on the ground a fair bit. Spots and barring look absent. But... I’m pretty sure that this a Spotted dove Streptopelia chinensis, though I had trouble realising this since the diagnostic spotted patch on the neck isn’t visible in my photos. Or am I wrong?

Shrikes. Now we come to passerines, of which I saw a bunch. I’ll go through them in a very rough sort of phylogenetic order, rather than in the order in which I encountered them. I saw shrikes in several places, often in towns and right next to tower blocks and in very urban settings (so long as there are trees and green spaces, there can be birds). All appeared to belong to the same species, one with a warm brown mantle, grey crown and nape, black wing feathers but for a small, white, rectangular panel on the primaries, and long tail that was dark on its upper surface. Of the 12 shrike species in the region, this description applies only to the Burmese shrike Lanius colluroides, the black (rather than streaked white) forehead further showing that I only ever saw males… which figures, because they were usually singing.

Caption: Burmese shrike Lanius colluroides, two different individuals (the one at left is singing). This species occurs throughout south-east Asia as well as China and is mostly associated with lowland forests. Image: Darren Naish.

My impression in the field was that I was looking at Red-backed shrike L. collurio – a species I know well from fieldwork in Romania – but the Red-backed (which does occur in China) is quite different, mostly in being shorter-tailed. Furthermore, the Red-backed shrikes in China are restricted to the far north of the country and belong to the pale subspecies L. c. pallidifrons, the mantle of which is washed out relative to the reddy-brown present on Burmese shrikes and Red-backed shrikes in Europe. Shrikes are corvoids, by the way, and thus outside the clade – Passerida – that contains all the other passerines I’ll be talking about.

Sylvioids 1: bulbuls and laughingthrushes. Bulbuls, babblers, laughingthrushes and allied pointy-billed sylvioid passerines are not that typical of western Europe, so it was fairly thrilling for me that my first passerine of the entire trip was the Light-vented bulbul Pycnonotus sinensis, which I saw a lot and often right in the middle of urban areas (again, so long as there were trees).

Caption: Light-vented bulbul Pycnonotus sinensis. Different individuals seen, variously, in an ornamental garden and in a planted region in the middle of a heavily pedestrianised area. Images: Darren Naish.

I also saw White-browed laughingthrushes Pterorhinus sannio at many places, including parks and gardens. I was often able to get really close to them. They forage on the ground a lot, often in pairs or small groups, and also hang around in low vegetation. I was also happy to see Red-billed leiothrix Leiothrix lutea in the wild, a small laughingthrush well known outside of Asia as a cage bird. Leiothrixes are among those many passerines where the vernacular name is the same as the scientific one. Other examples include tesias, liocichlas, eremomelas, prinias, cisticolas, hyliotas, batises, tschagras and so on and on.

Caption: at left, White-browed laughingthrush Pterorhinus sannio singing. At right: Red-billed leiothrix Leiothrix lutea. Images: Darren Naish.

Sylvioids 2: leaf warblers and bush warblers. Below, we see a leaf warbler (or phylloscopid). There are about a million leaf warbler species in China and they’re notoriously difficult to identify with confidence, certainly so when you’re looking at poor photos and not with the birds in front of you. I initially reckoned that this might be a Yellow-browed warbler Phylloscopus inornatus on account of the two whitish wing bars. However, the bird I saw has a distinct central crown stripe, which is supposed to count that species out. A better match might be Pallas’s leaf warbler P. proregulus (a phylloscopid I always remember from field guides because it’s sometimes positioned close to kinglets, and both this and its specific name imply that it’s a ‘proto-kinglet’, which it totally isn’t). This is in keeping with the small bill and whiteish underside, plus P. proregulus is common across much of China and nearby (MacKinnon & Phillipps 2000).

Caption: definitely a phylloscopid… and perhaps a Pallas’s leaf warbler Phylloscopus proregulus. Both images show the same individual. Images: Darren Naish.

Phylloscopus leaf warblers are familiar birds to me (there are a few TetZoo ver 2 and 3 articles about them, or there used to be…), but I’d never before seen any member of the cettiid warbler genus Abroscopus. This (below) is the Rufous-faced warbler A. albogularis, a fairly common bush warbler of woods and thickets with a set of distinctive facial markings. My impression on seeing this bird in the field was that it was a fulvetta but I became confused when the markings totally didn’t match any known fulvetta species. Please excuse the terrible photo.

Caption: blurry Rufous-faced warbler A. albogularis, photographed in the gardens of the Zigong Dinosaur Museum. Image: Darren Naish.

Bushtits and actual tits. The same applies to my photos of Black-throated tit Aegithalos concinnus, an aegithalid (bushtit or long-tailed tit) I saw several times while individuals, often in mixed flocks with warblers, foraged in vertical and hanging poses. A few very similar aegithalids also occur in China – like the Rufous-fronted tit A. iouschistos and Black-browed tit A. bonvaloti – but the Black-throated has unmistakeable markings. Aegithalids are not really tits at all, by the way, but are instead close kin of phylloscopid and sylviid warblers (Jønsson & Fjeldså 2006, Selvatti et al. 2015) and thus deep within Sylvioidea. True tits (Paridae) appear to be an early-diverging lineage within Sylvioidea.

Caption: Black-throated tit Aegithalos concinnus, showing the head, throat, chest and belly markings diagnostic for this species. Images: Darren Naish.

Caption: this photo wasn’t taken in China, but in England, and shows an aegithalid species very familiar to European people like myself: the Long-tailed tit A. caudatus, which also occurs in China. Its long tail is not typical of all members of this group. Image: Darren Naish.

Of proper tits, I had good views of what I assumed were Great tit Parus major, a species which does occur across much of southern China. However, the Great tits in China have a white border to the black belly stripe and a single white wing bar, whereas the tit I saw (and photographed, really badly) had a yellow border to its belly stripe and two white wing bars. This means it must have been the Green-backed tit P. monticolus, and perhaps the subspecies P. m. yunnanensis (the more eastern form P. m. legendrei has a much wider black belly stripe, and the other subspecies occur further west or in Taiwan). Harrap & Quinn (1996) made the point that the relationship between Green-backed and Great tits is not well understood, since both have overlapping ecological preferences in some parts of their ranges and can even occur in the same feeding flocks. The Green-backed tit also occurs in places where there are distinct lowland and highland Great tit subspecies on either side, which is confusing. In general, the Green-backed tit seem to be a highland relative of the Great tit, more closely associated with wetter forests.

Caption: really bad photos of a tit which turned out to be a Green-backed tit Parus monticolus. Lighting conditions were often against me when I was getting these photos. Image: Darren Naish.

Pipits and wagtails, and sparrows. This (below) is an Olive-backed pipit Anthus hodgsoni, one of several of these birds that I watched foraging in rough ground in a heavily built-up area. Pipits are a really interesting group of passerines that have many adaptations for life in open areas like grasslands, meadows and tundra but there are also species of woodlands, rocky coasts and watercourses. They’re often leggy (for passerines) and with notably long hallux claws.

Caption: Olive-backed pipit Anthus hodgsoni, in characteristic theropod skulking pose. The Olive-backed pipit is a widespread Asian species, occurring from the edge of the Urals to the coasts of the Pacific and Indian oceans. Image: Darren Naish.

Pipits are closely allied to wagtails (both belong together within Motacillidae), and I saw one representative of that group too: the White wagtail Motacilla alba, a species well known for occurring in pedestrianised areas and other places with big, flat expanses of nothing. The White wagtail is well known for being highly variable across its vast range and numerous subspecies have been named (cue debate about which of these warrant specific status…). The one I saw is M. a. alboides, sometimes called Hodgson’s wagtail and associated with Laos, Vietnam, Myanmar and the Himalayas as well as the southern half of China (Alström & Mild 2003). Motacillids, incidentally, are part of the passerine clade Passeroidea, which is weird because it means that they’re surrounded in the phylogeny by sparrow-like birds (e.g., Selvatti et al. 2015).

Having mentioned sparrows, I saw Eurasian tree sparrow Passer montanus on several occasions, which is not surprising since this is the sparrow of China. House P. domesticus and Spanish P. hispanicus sparrows occur in China too, but only at comparatively few spots in the far west. China is also home to the Rock sparrow Petronia petronia and several snowfinches (Montifringilla).

Caption: at left, two different Hodgson’s wagtail Motacilla alba alboides, a subspecies of White wagtail. At right: Eurasian tree sparrow Passer montanus. Images: Darren Naish.

Thrushes and Old World flycatchers. Let’s talk briefly about thrushes. The blackbirds in China – here I’m talking about the black thrushes typically called ‘blackbirds’, not the American ‘blackbirds’ included in the group Icteridae – have conventionally been regarded as subspecies of T. merula, the thrush that occurs across Europe, Asia and northern Africa where it’s mostly known as the Common or Eurasian blackbird. However, some authors now regard at least some Chinese blackbirds as belonging to a distinct species: the Chinese blackbird T. mandarinus. Sichuan is apparently home to the subspecies T. m. sowerbyi, so this might be the bird I saw. In the field, the males struck me as being slightly greyer on the wings and browner on the body than the blackbirds at home in England, but the differences were minor.

Caption: a blackbird, foraging at the edge of a pond where stones have been stuck into cement. I would have thought that this is a Common or Eurasian blackbird Turdus merula, but it might be a Chinese blackbird T. mandarinus. Image: Darren Naish.

Thrushes are closely allied to Old World flycatchers, properly called Muscicapidae. China is home to loads of them, among them wheatears, stonechats, forktails and other chats, various redstarts, robins, nightingales, shortwings, bush robins and rock thrushes, many Ficedula and Muscicapa flycatchers, various niltavines, and others. I wasn’t in the right sort of places to see any of these, but I did see an iconic Asian member of the group: the Oriental magpie-robin Copsychus saularis, a familiar species of gardens and forests. Magpie-robins – also called shamas – are unusual enough that (together with the Cercotrichas scrub robins) they belong to their own muscicapid lineage, Copsychini (Sangster et al. 2010). Magpie-robins are sexually dimorphic. Males are strikingly black and white while females are mostly grey on the head and body, and I saw both.

Caption: Oriental magpie-robin Copsychus saularis male and female (male at top, female below). The male in the images here lived right next to a factory. Image: Darren Naish.

Caption: another member of the muscicapid clade Copsychini, a male White-rumped shama Copsychus malabaricus. This one was photographed in captivity in the UK, not in Asia. Image: Darren Naish.

Starlings. China is inhabited by about 20 starling species, meaning that someone only familiar with the dark, iridescent Common starling Sturnus vulgaris – like me – is potentially in for a real treat. Alas, my only sightings were of the gregarious Red-billed starling S. sericeus. Like many of the Asian Sturnus species, its plumage combines black wing feathers with white patches, a varicoloured look to the body and a distinctly demarcated head. The birds I photographed look darker than those in many images of this species online but that’s mostly because I had to up the contrast to make them usable.

Caption: Red-billed starling Sturnus sericeus in downtown Zigong. There were about 15 birds in this group; the bird shown at left is the same individual seen at far right in the photo on the right. Image: Darren Naish.

And that’s it! I emphasise that the birds I’ve discussed here weren’t the sort that people travel half-way round the world to see, or go to remote places to tick off their lists. On the contrary, these were all birds that were easy to see in urban and suburban settings and my seeing of them was mostly opportunistic and done with minimal effort. My point in discussing the birds I saw was to explain what a normal person, interested enough in wildlife to go and look for it but not to spend huge sums of money on dedicated adventures, might bump into. The answer is… quite a lot, even in these times of environmental degradation and destruction. Some of my identifications could well be off, in which case please feel happy to correct me. More birds here sometime real soon, thanks for reading.

If you enjoyed this article and would like to see me do more, please consider supporting this blog (for as little as $1 per month) at patreon. The more support I receive, the more financially viable this project becomes and the more time and effort I can spend on it. Thank you :)

 For previous TetZoo articles relevant to the birds discussed here, see…

• Great tits: still murderous, rapacious, flesh-rending predators!, February 2013

• For The Love of Crows, October 2015

• Thoughts on the Passerine Tree, 2016, October 2016

• A Battle Among Blue Tits, February 2018

Refs - -

Alström, P., Mild, K. & Zetterström, B. 2003. Pipits and Wagtails of Europe, Asia and North America. Christopher Helm, London.

Harrap, S. & Quinn, D. 1996. Tits, Nuthatches and Treecreepers. A & C Black, London.

Jønsson, K. A. & Fjeldså, J. 2006. A phylogenetic supertree of oscine passerine birds (Aves: Passeri). Zoologica Scripta 35, 149-186.

MacKinnon, J., & Phillipps, K. 2000. A Field Guide to the Birds of China. Oxford University Press, Oxford.

Sangster, G., Alström, P., Forsmark, E. & Olsson, U. 2010. Multi-locus phylogenetic analysis of Old World chats and flycatchers reveals extensive paraphyly at family, subfamily and genus level (Aves: Muscicapidae). Molecular Phylogenetics and Evolution 57, 380-392.

Selvatti, A. P., Gonzaga, L. P. & Russo, C. A. de M. 2015. A Paleogene origin for crown passerines and the diversification of the Oscines in the New World. Molecular Phylogenetics and Evolution 88, 1-15.

Cocks-of-the-Rock, Extreme Cotingas

Among the most flamboyant and striking of South American birds are the two Rupicola species, known commonly as ‘cocks-of-the-rock’ (though it looks really odd seeing the name written as a plural like that).

Caption: the very first image of a cock-of-the-rock I ever recall seeing. From the cover of Charles Tunnicliffe’s Tropical Birds of 1960. This is one of the famously influential ‘tea card’ books, where you have to collect the cards to complete the book. Image: Darren Naish.

These two species – the Guianan cock-of-the-rock R. rupicola of the Guianan Shield and the Andean cock-of-the-rock R. peruvianus of the tropical Andes (from Venezuela in the north to Peru in the south) – are members of Cotingidae, a large group of South American passerines that’s part of Tyrannides or Tyrannida, a major clade within the suboscines. Suboscines (also called Tyranni) also includes the ovenbirds of the Americas, and the Old World pittas, broadbills and kin.

Caption: a much-simplified depiction of passerine phylogeny. Suboscines and oscines form the two great groups. This diagram is one of a huge number produced for my in-prep textbook on the vertebrate fossil record, on which go here. Image: Darren Naish.

I’m mostly writing about them because I’ve essentially never written about cotingas at TetZoo at all, nor about their close relatives (the tityras and kin, the manakins and so on). I have, however, written about an essential book on these birds: Guy Kirwan and Graeme Green’s 2011 Cotingas and Manakins, an indispensable work on these groups (my review is here, though it’s now missing all the images that originally made it fun to look at, SIGH).

Caption: if you’re seriously interested in cotingas and manakins (and their close kin), you should obtain Kirwan & Green (2011). It’s a brilliant book. Image: Christopher Helm.

Cocks-of-the-rock are unusual enough that they were regarded as worthy of their own family (Rupicolidae) until as recently as the 1970s. Details of the thigh arteries were thought by some experts to indicate possible closeness to tyrant-flycatchers rather than to cotingas but in several aspects of anatomy (like syringeal type), they’re fairly typical cotingas. In 1971, cotinga expert David Snow sent Charles Sibley a cock-of-the-rock egg collected from Guyana, the resulting experiments on the egg’s chemical composition proving, to Sibley’s satisfaction, that Rupicola should be included within Cotingidae (Snow 1973). More specifically, molecular data groups them with Phoenicircus (red cotingas) and perhaps with Snowornis (green pihas) in a clade that’s named Rupicolinae (Ohlson et al. 2007, Tello et al. 2009). It should be noted that Phoenicircus is sufficiently unusual for a cotinga – it has carotenoid-rich, saturated red plumage, fused third and fourth toes and a manakin-like gestalt – that it has at times been suggested, erroneously it seems, to be an ally of manakins (Snow 1973).

Caption: Guianan red cotinga (Phoenicircus carnifex) in hand. What a striking bird. Image: Etienne Littlefair, wikipedia, CC BY 2.5 (original here).

Cocks-of-the-rock are birds of tropical and subtropical montane forests, most typically those with rocky gorges and areas where there are caves and large boulders. Such places are crucial for nesting: the nests (which are made of mud, vegetation and a bit of saliva) are constructed on the vertical side of a cave or rock in a shaded location, often close to running water. Nesting is also semi-colonial (Kirwan & Green 2011). Having said that they’re montane forest birds, there’s a single record of a Guianan cock-of-the-rock in the northern savannahs of Surinam, this perhaps being the consequence of a long dry season that forced the bird to move. They’re otherwise mostly sedentary but are powerful, agile fliers.

Caption: images showing Rupicola in life virtually always show them in forested settings, but they also frequent caves, the walls of ravines, and boulder fields. These photos, showing a female Andean cock-of-the-rock at her nest and while elsewhere in a cave, were taken in the Cueva del Higueron, Peru. Images: JYB Devot, wikipedia, CC BY-SA 4.0 (originals here and here).

Both Rupicola species are large as cotingas go, with males reaching 33-34 cm in total, and they’re spectacularly red or orange. Sexual dimorphism is pronounced, the most obvious differences involving the big, fan-shaped dorsal crests of males. The crest is formed of two rows of feathers that are in close contact along their middle surfaces. In the Guianan R. rupicola, silky filaments emerge from the rump and back and trail from and over the animal’s sides. Females are darker and browner than males and with a crest that’s more of a tuft than a giant dorsal fan. Both species are lek breeders, the Andean species perching on lianas and other structures some metres off the ground while the Guianan species does its displaying on the ground.

Caption: male Guianan cock-of-the-rock, showing characteristic filaments and ‘orange peel’-like feathers on the back. Image: Aisse Gaertner, wikipedia, CC BY SA 4.0 (original here).

Numerous vocalisations – some likened to chicken crowing and cat meowing, there’s also a bugling ‘assembly call’ – are made at the leks, and also while foraging and when calling attention to the sighting of a predator. A modified tenth primary feather is used by the Guianan species to make a whistling noise.

Caption: male captive Andean cock-of-the-rock, photographed at San Diego Zoo. The lush black wings and lack of trailing filaments make this species look very different from the Guianan species. Not all Andean cocks-of-the-rock are the same: there are at least four distinct populations, conventionally identified as subspecies. Image: Jerry Thompson, CC BY 2.0, wikipedia (original here).

The bill is long, broad-based and slightly hooked but usually mostly hidden by the crest. It’s used to procure both fruit as well as arthropods and small vertebrates. While these birds are best characterised as frugivorous, it’s interesting that they also catch and eat frogs, lizards and small snakes and such items are said to be important in the diet of nestlings (Kirwan & Green 2011). Mice have been eaten by captive Andean cock-of-the-rock. Such raptors as hawk-eagles, accipiters and forest falcons are known to prey on Rupicola (Kirwan & Green 2011). UPDATE: there are also observations of them chasing and eating small passerines, and this might even be a regular habit (Mahecha et al. 2018). Thanks to Max Kirsch for passing on this information.

Caption: male Guianan cock-of-the-rock, in a pose which allows us to see the length of the bill through the lower part of the fan of feathers. Note that this individual is missing part of one of his toes. Image: Juniorgirotto, wikipedia, CC BY-SA 4.0 (original here).

In combining frugivory with large size, marked sexual dimorphism and especially elaborate sexual displays, cocks-of-the-rock are ‘extreme’ cotingas, superficially similar to the distantly related bellbirds (Snow 1973), and in some ways suboscine ‘equivalents’ of the even more distantly related birds-of-paradise (Kirwan & Green 2011).

Caption: museum specimens of Rupicola don’t fare well after decades in sunlight, it seems. I’ve never seen a live cock-of-the-rock… so far, only museum specimens like this Guianan one. Image: Darren Naish.

Needless to say, there’s tons more to say about cotingas and their allies, but this, at least, is a start.

For previous TetZoo articles on passerines (concentrating, once again, on the few articles that haven’t been destroyed via the removal of their images), see…

• Great tits: still murderous, rapacious, flesh-rending predators!, February 2013

• For The Love of Crows, October 2015

• Thoughts on the Passerine Tree, 2016, October 2016

• A Battle Among Blue Tits, February 2018

If you enjoyed this article and want to see me do more, more often, please consider supporting me at patreon. The more funding I receive, the more time I’m able to devote to producing material for TetZoo and the more productive I can be on those long-overdue book projects. Thanks!

Refs - -

Kirwan, G. & Green, G. 2011. Cotingas and Manakins. Christopher Helm, London.

Mahecha, L., Villabona, N., Sierra, L., Ocampo, D. & Laverde-R., O. 2018. The Andean Cock-of-the-rock (Rupicola peruvianus) is a frugivorous bird predator. The Wilson Journal of Ornithology 130, 558-560.

Ohlson, J., Prum, R. O. & Ericson, P. G. P. 2007. A molecular phylogeny of the cotingas (Aves: Cotingidae). Molecular Phylogenetics and Evolution 42, 25-37.

Snow, D. W., 1973. The classification of the Cotingidae (Aves). Breviora 409, 1-27.

Tello, J. G., Moyle, R. G. Marchese, D. J. & Cracraft, J. 2009. Phylogeny and phylogenetic classification of the tyrant flycatchers, cotingas, manakins, and their allies. Cladistics 25, 429-467.

Potoos As An Internet Phenomenon

This might be an unusual TetZoo article. I like memes, by which I mean the internet images or concepts that are passed ‘virally’ from one person to another and become modified and/or added to across their ‘generations’. As you’ll know if you pay any attention to memes (or are part of any community where memes are frequently encountered), several animal species are meme favourites. Among them are potoos.

It’s true, I’m guilty of using potoos in memes myself. The one at left was my profile picture on social media for a while; the one at right appeared at TetZoo ver 3. The original photo has been memed a lot. The original photo is sometimes credited to Kristin Lundquist, though that’s not where I got it from. Image: (c) Kristin Lundquist.

Potoos – officially nyctibiids, and not to be confused with the primates called pottos – are a South, Central and North American group of cryptically coloured, nocturnal, big-eyed, insectivorous birds. Nearly all of the seven extant species* are included within the same genus (Nyctibius), the exception being the Rufous potoo N. bracteatus which was given its own genus (Phyllaemulor) in 2017. In addition, there are fossil potoos (from Europe and North America) which have been given separate genera too. Potoos hunt by aerial hawking or by flycatching from a perch, their prey mostly involving beetles and moths. They’ve also been reported to eat small passerines: a Northern potoo N. jamaicensis was once found to contain a White-collared seedeater Sporophila toqueola in its stomach (Cleere & Nurney 1998). But they’re also famously sedentary, spending the day sitting still on a branch or stump where their plumage, shape and posture helps conceal them from predators. Unique notches in their eyelids enable them to see even when the eyelids are closed, and their short, stocky tarsometatarsi appears to be an adaptation for long periods of sitting still.

* Genetic variation within various of these species suggests that this count is too low and it’s very likely that a set of cryptic species are awaiting recognition (Cohn-Haft 1999).

Potoos have an obvious similarity with nightjars, frogmouths and kin, and hence have traditionally been classified alongside them within Caprimulgiformes. While there’s an awful lot to say about caprimulgiform evolution and diversity and where these birds fit within the neornithine family tree, we’ll ignore all that for now since that’s not why we’re here.

Two of a set of famous potoo-themed photos (there are at least four in total). These went viral in 2015 and finding a photographer to credit has not been possible, but if there’s anyone in particular who should be credited, I’d be interested in knowing their name. This is definitely a Great potoo Nyctibius grandis (or, part of the series of populations currently included within that species, anyway).

Potoos, frankly, sometimes look scary. In the Great potoo N. grandis, the giant eyes have dark brown irides, meaning that they sometimes look entirely black. This is a marked difference from other potoos, all of which have orange, yellowish or yellow-green irides, though the Rufous potoo is also unusual, this time in having a dark vertical wedge in the lower half of its iris (Cohn-Haft 1999). The Great potoo – the largest of the family – is also odd in being big, reaching 54 cm in total length and with a wingspan of around 80 cm. I guess it’s not called the Great potoo for nothing. A bird of this sort, at this size, is somewhat daunting.

Potoos and some amused (or bored) owls. I love this picture. It’s here on imgur. Image: princeemberstorm.

But potoos can also look comical, cute and more like puppets or cartoon characters than real animals, so – conversely – they also appeal to us for those reasons. Their giant, often bright orange eyes sometimes look like billiard balls and appear unrealistically large within their heads. A small, slim, curved bill accentuates this big-eyed look, though when I talk of the bill here, I’m referring to the strongly hooked anterior portion and not to the wide gape, virtually all of which is concealed when the bird has its mouth closed.

Potoos are just ripe for things like this, it seems. This image, titled ‘Potoo is a sir’, appeared on imgur in 2014 and is borrowed from here. Image: (c) Polarbearsarentreal.

Add all of this together and we come to the reason for this article. Within recent years, potoos have been cartoonified, memed and caricatured to hell, so much so that we might talk of The Potoo As An Internet Phenomenon. I don’t know if any of this happened to potoos before there was an internet, but I don’t see evidence that it did. What’s happened here is the same as that for anything we regard as an internet meme: people saw some cool, interesting pictures and were inspired to depict their own take on them, and other people were inspired by those images, and we then get the domino effect whereby things get mixed and matched, elaborated, or taken in a whole new direction. Keep reading to see where this goes.

Potoo-themed accounts of Twitter. The avatar at left is that of illustrator Angela Hsieh, aka @hisiheyah. A selection of others are at right: our lord and saviour potoo or @PotooPotoo is the most relevant for the purposes of the article here. Images: Angela Hsieh, Twitter.

Part of the story of the potoo’s popularity onlines comes from the appearance of a series of photos, apparently taken in Venezuela in 2013, that show a Great potoo sat on a fence in various poses (two are shown above). The bird looks especially striking in these photos due to its massive and seemingly fully black eyes, its (perhaps surprisingly large) size, and a streamlined look which maybe makes it look somehow unnatural. Plus, it’s a potoo. I mean, seriously, they all look striking if you haven’t seen one before. On size: we can see from accompanying objects (barbed wire, humans hands) that the bird isn’t really that big, but it was big enough (ha ha, another meme) to inspire this, which I like very much…

‘The Great Potoo’, interpreted somewhat literally, from the online comic Question Duck (original panel here). Image: (c) Question Duck.

The popularity of these photos is also partly explained by the fact that they were used in some bullshit story about a ‘dinosaur owl’ being resurrected from ancient DNA (there’s even a Snopes takedown of that concept), plus people who’ve never heard of books (let alone potoos) have claimed variously that the animal might be an alien, a demon or a piece of created taxidermy. Karl Shuker discussed his investigation of the photos at his blog, here.

Where have people gone from there? Some of you will know that griffons … or griffins, or gryphons, or gryphins … are big on the internet these days. For whatever reason, they’ve brought out people’s creative side, and there are griffin-inspired creatures of all sorts, depicted variously in attractive fantasy art, in pokemon-style cartoonish art, in anatomically rigorous hyperdetailed art, and even in furry costume form. I can’t mention furry costumes without bringing your attention to the fact that, yes, at least one person has made a potoo cosplay, and it’s spectacular. Here’s Casanova the potoo, as made by the fantastic people at Menagerie.

Other potoo-themed costumes are now available - I’m pretty sure that Casanova is not a one-off. Image: (c) SarahDee/Fur Affinity, original here.

But back to griffins. I say that griffins are interesting “for whatever reason”, but the real reason, of course, is that they’re awesome, combining the most visually compelling parts of some of the world’s most attractive and popular animals, by which I mean big raptors and big cats. I’ve always really liked griffins myself, and I remember being thrilled when discovering that people even had the audacity to invent an even-more-elaborate griffin spin-off, the Hippogriff!

Combine the attractive qualities of griffins with a new Golden Age of inventive creature art, and with the existence of potoos, and with the fact that potoos are an internet phenomenon, and the inevitable consequence is … potoo griffins. Yes, there are many potoo griffins out there. Here are just two illustrations of them…

Cartoon potoo griffins, by Cyndi Foster, aka Gingo, aka Gryphon Queen (here at DeviantArt). This is why the internet was made. Images: (c) Cyndi Foster/Gingo.

And this sort of thing – the combining of animal parts to create chimaeras that stun or surprise us by virtue of how absurd, or silly or compelling or realistic or wonderful they are – has led to yet more potoo-inspired creatures of the internet. I give you: a potoo x marbled polecat chimaera, a potoo x black panther chimaera, a potoo x Pallas cat chimaera, and a potoo x Chihuahua chimaera. Brilliant (and all credit to the artists). There are many, many others.

At left, a marbled polecat x potoo griffin, “the most majestic and noble of griffins”, by uropygid (original here). At right, a potoo griffin that combines black panther and potoo features, by Seneca’s Art Rocks. Images: (c) Uncle Max/uropygid, Seneca’s Art Rocks.

Potoo x Pallas cat by iguanamouth (from their “kept getting requests for gryphons so heres a bunch of them At Once “ project), Potoo x Chihuahua by Pechschwinge, from their Daily Gryphon Challenge. Images: (c) iguanamouth, Pechschwinge.

 Yes, truly we are in the age of peak potoo, a time when we might pay reverence to Our Lady Potoo of the Sacred Heart, or Our Lord and Savior Potoo Bird, or something along those lines. What’s that, you say – this would work as a great internet image as well? Well…

‘Our Lord and savior potoo bird’. This image is by dragongirl222, who does a whole range of potoo-themed merchandise at redbubble. Image: (c) dragongirl222.

This, of course, is not everything. There’s even more out there — much more — and it’s easy to find if you go look for it. Dear reader: I give you… The Potoo As An Internet Phenomenon.

Thanks to those supporting this work – and the very blog itself – via pledges at patreon. You can support what I do and see works-in-prep behind the scenes, via pledges as small as $1 per month.

For previous TetZoo articles relevant to potoos, see…

• Tet Zoo Bookshelf September 2016: of Fossil Primates and Nightjars, September 2016

• Pouches of the Sungrebe, November 2018

Refs - -

Cleere, N. & Nurney, D. 1998. Nightjars: A Guide to Nightjars and Related Nightbirds. Pica Press, Mountfield.

Cohn-Haft, M. 1999. Family Nyctibiidae (potoos). In del Hoyo, J., Elliott, A. & Sargatal, J. (eds) Handbook of the Birds of the World, Vol. 5. Barn-owls to Hummingbirds. Lynx Edicions, Barcelona, pp. 288-301.

A Multi-Species Nesting Assemblage in the Late Cretaceous of Europe

You don’t have to be an expert on the fossil birds of the Mesozoic Era to know that our knowledge of these animals has increased exponentially in recent years. An extraordinary number of new species have been described, we’ve learnt a great deal about their anatomy thanks to spectacular new fossils – some of which are even preserved in amber – and we’ve gained insights into their behaviour and ecology thanks to discoveries made about their teeth, feathers, stomach contents, phylogeny and the environments in which they lived.

Enantiornithines — here are just a few of them. In-prep montage from my in-prep textbook. Image: Darren Naish.

Among the most important and species-rich of Mesozoic bird groups are the enantiornithines, or ‘opposite birds’, so named because a few aspects of their skeletal anatomy (the way their shoulder and chest bones fit together in particular) are unusual relative to those of modern birds. Enantiornithines are known from rocks worldwide and were present from the start of the Cretaceous until its close 66 million years ago. They might even have evolved in the Jurassic, in which case older members of the group await discovery.

Among the many interesting things discovered recently about enantiornithines is that at least some of them were colonial nesters. In a Naturwissenschaften paper published in 2012, Gareth Dyke, Mátyás Vremir, Gary Kaiser and myself reported a remarkable fossil assemblage: a big, lens-shaped mass of calcareous mudstone (about 80 cm long, 50 cm wide and 20 cm deep) packed with literally thousands of enantiornithine eggshell fragments. A few enantiornithine bones were present as well, but eggshell fragments form 70-80% of the entire mass (Dyke et al. 2012).

Different chunks of the (originally lens-shaped) Oarda de Jos eggshell assemblage. You can see abundant eggshell fragments (a, b) as well as crushed but complete eggs (the image at bottom). Scale bars = 1 cm. Image: Vremir, Dyke et al.

This eggshell mass was found at Oarda de Jos near Sebeş, Transylvania, western Romania and comes from the latest Cretaceous Sebeş Formation (Dyke et al. 2012). Pleurodire turtles, azhdarchid pterosaurs and such dinosaurs as ornithopods and the peculiar Balaur bondoc (which is probably a flightless member of the bird lineage, not a dromaeosaur as originally proposed: see Cau et al. 2015) also come from the Sebeş Formation. I wrote about the discovery and initial interpretation of the eggshell assemblage at TetZoo ver 3, though (sigh) it now appears without any of its images.

The Romanian maniraptoran theropod Balaur bondoc, originally published as a dromaeosaurid, has a number of features which indicate that an avialan position might be more likely, and this is the position it has occupied in several phylogenetic analyses. If it really is an avialan, it has to be interpreted as a big, secondarily flightless member of the group. We explored this idea in Cau et al. (2015). Image: Emily Willoughby.

As described in our 2012 paper, the assemblage is a fairly big deal, since it means that colonial nesting was practised by at least some enantiornithine species, is not unique to crown-birds, and evolved in birds more stem-ward than other colonially nesting birds (Naish 2014).

But as revealed in our new paper, published in Scientific Communications this past week and led by Mariela Soledad Fernández, things turn out to be a bit more complex than we originally thought. Rather than consisting of enantiornithine eggshell fragments and bones alone, the assemblage actually contains eggshell fragments (and probably bones) of several different, additional animal groups. Namely, gekkotan lizards, crocodylomorphs, and a bird different from the enantiornithine otherwise so well represented in the assemblage (Fernández et al. 2019).

Examined under microscopes (A-B show thin-sections viewed with a standard light microscope; C-D views from the SEM), eggshell fragments look like this. These images show the crocodylomorph eggshell in the assemblage. Image: Fernández et al. (2019).

It should be noted to start with that enantiornithine remains dominate the assemblage by far, around 70% of the sampled eggshell fragments belonging to that group (and presumably to the same one species). Sadly, the gekkotan and crocodylomorph eggshell fragments aren’t informative enough to tell us anything particularly interesting about the species concerned, other than that their remains are present. The Oarda de Jos crocodylomorph eggshell is different in thickness and microscopic surface texture from crocodylomorph eggshell fragments reported from the Upper Cretaceous of the USA and Brazil and is most similar to fossil eggs from the Eocene of Colorado, called Krokolites wilsoni (Hirsch 1985). But we don’t have a good handle on what sort of crocodylomorph we’re talking about. After the enantiornithine, its eggs are the most abundant in the sample, forming about 28% of the assemblage. Those artistic reconstructions previously created for the location are thus in error: they really should have at least a few crocodylomorphs in view.

Remember this scene? Produced in 2012 by Julio Lacerda, it depicts the possible appearance of the enantiornithine nesting colony we infer for the locality. Maybe some of the colony did look like this. But it now seems that a few crocodylomorphs and the odd lizard were in the immediate area as well. Image: Julio Lacerda. UPDATE: this is a horribly lo-res version of the image, I aim to publish a better one in time.

The gekkotan eggshell pieces – they have an eggshell morphology termed ‘geckoid’ – have features in common with the eggs of modern geckos, and hence were presumably produced by crown-geckos (Fernández et al. 2019). Beyond that, we can say no more. Less than 1% of the eggshell in the assemblage comes from this lizard, so we’re not saying that its eggs are abundant in the sample.

‘Geckoid eggshell’ in the Oarda de Jos assemblage, as seen via SEM. The images (note the different scales) show (A) a distinct two-layered structure and (B) numerous tiny holes in the prisms of the second later. Image: Fernández et al. (2019).

Similarly, the second bird in the assemblage appears (from microscopic details of eggshell anatomy) similar to crown-birds – more so than to enantiornithines – but cannot be matched with any specific bird group and might represent something new (Fernández et al. 2019). So, we don’t know exactly what sort of bird we’re dealing with. Again, less than 1% of the eggshell in the assemblage is of this type, so it’s rare in our sample.

Piecing all of this together, what does it all mean? If our enantiornithine eggshell assemblage doesn’t involve enantiornithines alone, but also includes the remains of a second bird, a lizard and a crocodylomorph… do we have an example here of a multi-species nesting colony, perhaps one involving so-called parasitic nesting or even communal or cooperative nesting?

Several examples of this sort of thing are known for the modern world. They involve turtles laying their eggs at the edges of crocodylian nests, South American geckos which lay their eggs within the nests of cormorants and gulls, and seemingly harmonious nesting associations involving rheas, tinamous and penguins. Maybe the behaviours listed here occurred in Maastrichtian Romania. Perhaps the gekkotan lizard concerned was cheekily laying its (hard-shelled, perhaps sticky-shelled) eggs at the edges of enantiornithine nests, and maybe the mystery bird and crocodylomorph were non-threatening enough to be tolerated, their nests perhaps being close to those of the abundant enantiornithines (Fernández et al. 2019).

Opportunistic, parasitic, co-operative and harmonious nesting associations exist in the modern world; here’s an example where raptor nests (in this case, that of an Osprey Pandion haliaetus pair) invite the association of passerines, herons and others. Cases like this could well have existed in the Cretaceous. Image: D’Ami et al. (1969).

It may also be that the association we report is not quite as interesting as just described, but more to do with geological and hydrodynamic processes. That is, that the eggshell fragments and bones concerned became associated due to their presence in the same general floodplain area, their remains becoming mixed together by the actions of floodwater and not being all that informative as goes behaviour and ecology. Even if this is true, however, we can at least say that these animals were nesting in the same area and environment, and seemingly in proximity. That alone is interesting, and there are indications from elsewhere in the Cretaceous fossil record that it might have been a fairly regular occurrence.

Our paper is open access (OA) and available here; it’s one of several technical papers I hope to see published in the year. On that note, here’s a reminder that I’m not a salaried academic researcher and that any contribution I make to the technical literature is done in my own time. Thanks to those who support me via pledges at patreon, and please consider doing so if you don’t already.

For previous TetZoo articles relevant to Mesozoic birds, the Late Cretaceous animals of Romania and other relevant issues, see…

• A drowned nesting colony of Late Cretaceous birds, May 2012 (now missing all illustrations)

• A new azhdarchid pterosaur: the view from Europe becomes ever more interesting, January 2013 (now missing all illustrations)

• Bird behaviour, the ‘deep time’ perspective, January 2014

• The Romanian Dinosaur Balaur Seems to Be a Flightless Bird, June 2015

• Some Azhdarchid Pterosaurs Were Robust-Necked Top-Tier Predators, February 2017

While compiling this list I’ve discovered that essentially ALL of the TetZoo articles on enantiornithines are hosted at sites (ScienceBlogs and SciAm) that have stripped them of their original images. I must therefore make some effort to republish them here, with their pictures. Great, more stuff to do.

Refs - -

Cau, A., Brougham, T. & Naish, D. 2015. The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): dromaeosaurid or flightless bird? PeerJ 3: e1032.

D’Ami, R. D., Invernici, F. & Quochi, G. 1969. Animals of Lake and Marsh. Casa Editrice AMZ, Milan.

Dyke, G., Vremir, M., Kaiser, G. & Naish, D. 2012. A drowned Mesozoic bird breeding colony from the Late Cretaceous of Transylvania. Naturwissenschaften 99, 435-442.

Fernández, M. S., Wang, X., Vremir, M., Lauren, C., Naish, D., Kaiser, G. & Dyke, G. 2019. A mixed vertebrate eggshell assemblage from the Transylvanian Late Cretaceous. Scientific Reports 9, 1944.

Hirsch, K. F. 1985. Fossil crocodilian eggs from the Eocene of Colorado. Journal of Paleontology 59, 531-542.

Naish, D. 2014. The fossil record of bird behaviour. Journal of Zoology 292, 268-280.

The Most Amazing TetZoo-Themed Discoveries of 2018

As we hurtle toward the end of the year – always a scary thing because you realise how much you didn’t get done in the year that’s passed – it’s time to look back at just a little of what happened in 2018. This article is not anything like a TetZoo review of 2018 (I’ll aim to produce something along those lines in early 2019), but, rather, a quick look at some of the year’s neatest and most exciting zoological (well, tetrapodological) discoveries. As per usual, I intended to write a whole lot more – there are so many things worthy of coverage – and what we have here is very much an abridged version of what I planned.

Animals we will meet below, a montage. Images: (c) Philippe Verbelen, (c) Kristen Grace, Florida Museum of Natural History, Graham et al. (2018), CC BY-SA 4.0.

Thanks as always to those supporting me at patreon. Time is the great constraint (and finance, of course), and the more support I have, the more time I can spend on producing blog content. Anyway, to business…

The Rote leaf warbler. New passerine bird species are still discovered on a fairly regular basis; in fact three were named in 2018*. One of these is especially remarkable. It’s a leaf warbler, or phylloscopid, endemic to Rote in the Lesser Sundas, and like most members of the group is a canopy-dwelling, insectivorous, greenish bird that gleans for prey among foliage. Leaf warblers are generally samey in profile and bill shape, so the big deal about the new Rote species – the Rote leaf warbler Phylloscopus rotiensis – is that its bill is proportionally long and curved, giving it a unique look within the group. It superficially recalls a tailorbird. Indeed, I think it’s likely that the species would be considered ‘distinct enough’ for its own genus if there weren’t compelling molecular data that nests it deeply within Phylloscopus (Ng et al. 2018).

* The others are the Cordillera Azul antbird Myrmoderus eowilsoni and the Western square-tailed drongo Dicrurus occidentalis.

A Common chiffchaff Phylloscopus collybita encountered in western Europe, a familiar Eurasian-African phylloscopid leaf warbler. Image: Darren Naish.

The story of the Rote leaf warbler’s discovery is interesting in that it’s yet another recently discovered species whose existence and novelty was suspected for a while. Colin Trainor reported leaf warblers on Rote in 2004 but never got a good look at them, Philippe Verbelen observed them in 2009 and realised how anatomically unusual they were, and it wasn’t until 2015 that a holotype specimen was procured (Ng et al. 2018). I’ve mentioned before the fact that documenting and eventually publishing a new species is rarely an instant see it catch it publish it event, but a drawn-out one that can take decades, and here we are again. Also worth noting is that the existence of a leaf warbler on Rote was not predicted based on our prior knowledge of leaf warbler distribution in view of the deep marine channel separating Rote from Timor and lack of any prior terrestrial connection. Yeah, birds can fly, but members of many groups prefer not to cross deep water channels. In this case, this did, however, happen and most likely at some point late in the Pliocene (Ng et al. 2018).

Rote leaf warbler in life, a novel member of an otherwise conservative group. Image: (c) Philippe Verbelen.

Rote has yielded other new passerines in recent years – the Rote myzomela Myzomela irianawidodoae (a honeyeater) was named in 2017 – and it’s possible that one or two others might still await discovery there.

Neanderthal cave art. Hominins don’t get covered much at TetZoo, which is weird given the amazing pace of relevant recent discoveries and the fact that they’re totally part of the remit. I mostly don’t cover them because I feel they’re sufficiently written about elsewhere in the science blogging universe, plus I tend to be preoccupied with other things. Nevertheless, I take notice, and of the many very interesting things published in 2018 was Hoffman et al.’s (2018) announcement of several different pieces of Spanish rock art, seemingly made by Neanderthals Homo neanderthalensis. The art concerned involves hand stencils, abstract lines, squares and amorphous patches of pigment, always marked in red.

Red abstract markings, discovered in several Spanish caves, are old, and in fact were seemingly made by hominins long before H. sapiens moved into Europe. The red sinuous marking and system of squares and lines near the middle of this photo are purported to have been made by Neanderthals (other images, depicting animals and present adjacent to these markings, were seemingly created more recently by H. sapiens individuals). Image: (c) P. Saura.

The main reason for the attribution of this art to Neanderthals is its age: uranium-thorium dating shows that it’s older than 64ka, which therefore makes it more than 20ka older than the time at which H. sapiens arrived in Europe (Hoffman et al. 2018). That seems compelling, and it’s consistent with a building quantity of evidence for Neanderthal cultural complexity which involves the use of shells, pigments, broken stalagmites and so on.

One of the most famous pieces of claimed Neanderthal rock art: the Gorham's Cave ‘hashtag’ from Gibraltar. Image: (c) Stewart Finlayson.

I should add here, however, that I’m slightly sceptical of the use of age as a guide to species-level identification. Why? Well, we have evidence from elsewhere in the fossil record that the range of a hominin species can be extended by around 100ka without serious issue (witness the 2017 announcement of H. sapiens remains from north Africa; a discovery which substantially increased the longevity of our species). In view of this, would a 20ka extension of H. sapiens’ presence in Europe be absolutely out of the question? Such a possibility is not supported by evidence yet, and I don’t mean to appear at all biased against Neanderthals.

A tiny Cretaceous anguimorph in amber, and other Mesozoic amber animals. As you’ll know if you follow fossil-themed news, recent years have seen the discovery of an impressive number of vertebrate fossils in Cretaceous amber, virtually all of which are from Myanmar and date to around 99 million years old. They include tiny enantiornithine birds, various feathers (most recently racquet-like ‘rachis dominated feathers’), the tiny snake Xiaophis, early members of the gecko and chameleon lineages and the small frog Electrorana. Many of these finds were published in 2018 and any one could count as an ‘amazing’ discovery.

The Barlochersaurus winhtini holotype, from Daza et al. (2018).

However, there’s one fossil in particular that I find ‘amazing’, and it hasn’t received all that much coverage. It’s the tiny (SVL* 19.1 mm!), slim-bodied anguimorph Barlochersaurus winhtini, named for a single, near-complete specimen subjected to CT-scanning (Daza et al. 2018). Remarkable images of its anatomical details are included in Daza et al.’s (2018) paper. It has short limbs, pentadactyl hands and feet and a slim, shallow, bullet-shaped skull. Phylogenetic study finds it to be somewhere close to, or within, Platynota (the clade that includes gila monsters and kin, and monitors and kin), or perhaps a shinisaurian (Daza et al. 2018). It could be a specialised dwarf form, or somehow more reflective of the ancestral bauplan for these anguimorph groups. Either way, it’s exciting and interesting. What next from Burmese amber?

* snout to vent length

Barlochersaurus in life. It’s about the size of a paperclip. Image: (c) Kristen Grace, Florida Museum of Natural History (original here).

The Reticulated Siren. Sirens are very special, long-bodied aquatic salamanders with reduced limbs and bushy external gills. They’re very weird. They can reach 95 cm in length (and some fossil species were even larger), lack hindlimbs and a pelvis, have a horny beak and pavements of crushing teeth, and eat plants in addition to gastropods, bivalves and other animal prey. A longish article on siren biology and evolution can be found here at TetZoo ver 3.

A life reconstruction of the Cretaceous siren Habrosaurus, showing features typical of the group. This animal could reach 1.5 m in total length. Image: Darren Naish (prepared for my in-prep texbook The Vertebrate Fossil Record, on which go here).

Until recently, just four living siren species were recognised. But it turns out that indications of a fifth – endemic to southern Alabama and the Florida panhandle – have been around since 1970 at least. Furthermore, they pertain to a big species, similar in size to the Great siren Siren lacertina. Known locally as the ‘leopard eel’ (a less than ideal moniker, given that there’s a real eel that already goes by this name), this animal has been published by Sean Graham and colleagues in the open-access journal PLoS ONE (Graham et al. 2018) wherein it’s formally christened the Reticulated siren S. reticulata. It reaches 60 cm in total length, has dark spots across its dorsal surface and a proportionally smaller head and longer tail than other Siren species.

A museum specimen of the species has been known since 1970 when its finder noted that it did “not conform” to descriptions of known species, and live specimens were collected by David Steen and colleagues in 2009 and 2014. Again, note that discovery and recognition was a drawn-out process. The discovery has, quite rightly, received a substantial amount of media coverage, and many interesting articles about the find are already online. Many of you will already know of David Steen due to his social media presence and Alongside Wild charity (which I’m proud to say I support via pledges at patreon).

The Reticulated siren paratype specimen, as described by Graham et al. (2018). Image: Graham et al. (2018), CC BY-SA 4.0. Original here.

The idea that a new living amphibian species 60 cm long might be discovered anew in North America in 2018 is pretty radical. I’m reminded of the 2009 TetZoo ver 2 article ‘The USA is still yielding lots of new extant tetrapod species’ (which is less fun to look at than it should be, since images aren’t currently showing at ver 2). Furthermore, Graham et al. (2018) discovered during their molecular phylogenetic work that some other siren species are not monophyletic but likely species complexes, in which case taxonomic revision is required and more new species will probably be named down the line.

And that’s where I must end things, even though there are easily another ten discoveries I’d like to write about. This is very likely the last article I’ll have time to deal with before Christmas. As I write, I’m preparing to leave for the Popularising Palaeontology conference which happens in London this week (more info here), and then there are Christmas parties and a ton of consultancy jobs to get done before the New Year. On that note, I’ll sign off with a festive message, as is tradition. Best wishes for the season, and here’s to a fruitful and action-packed 2019. Special thanks once again to those helping me out at patreon.

For previous TetZoo articles relevant to various of the subjects covered here, see…

•  The USA is still yielding lots of new extant tetrapod species, July 2009

• THE AMAZING WORLD OF SALAMANDERS, October 2013

• Chiffchaffs: a view of passerines from the peripheries (part I), August 2014

• The Biology of Sirens, June 2016

Refs - -

Daza, J. D., Bauer, A. M., Stanley, E. L., Bolet, A., Dickson, B. & Losos, J. B. 2018. An enigmatic miniaturized and attenuate whole lizard from the mid-Cretaceous amber of Myanmar. Breviora 563, 1-18.

Graham, S. P., Kline, R., Steen, D. A. & Kelehear, C. 2018. Description of an extant salamander from the Gulf Coastal Plain of North America: the Reticulated Siren, Siren reticulata. PLoS ONE 13 (12): e0207460.

Hoffman, D. L., Standish, C. D., García-Diez, M., Pettitt, P. B., Milton, J. A., Zilhão, J., Alcolea-González, J. J., Cantelejo-Duarte, P., Collado, H., de Balbín, R., Lorblanchet, M., Ramos-Muñoz, J., Weniger, G.-Ch. & Pike, A. W. G. 2018. U-Th dating of carbonate crusts reveals Neandertal origin of Iberian cave art. Science 359, 912-915.

Ng, N. S. R., Prawiradilaga, D. M., Ng, E. Y. X., Suparno, Ashari, H., Trainor, C., Verbelen, P. & Rheindt, F. E. 2018. A striking new species of leaf warbler from the Lesser Sundas as uncovered through morphology and genomics. Scientific Reports 8: 15646.

Pouches of the Sungrebe

Among the most obscure and poorly known of the world’s living birds are the finfoots or heliornithids, a group of duck-sized, vaguely grebe-like swimmers of the American, African and south-east Asian tropics. There are just three extant species. Heliornithids are gruiforms (part of the crane + rail clade), recent studies indicating a close relationship with the Afro-Madagascan flufftails, a group conventionally included within the rail family but increasingly thought to represent a separate lineage termed Sarothruridae (García-R. et al. 2014).

Caption: the Sungrebe is a boldly marked heliornithid that occurs from southern Mexico in the north to Bolivia and northern Argentina in the south. It is c 30 cm long, remains relatively abundant, and is associated with swamps, marshes and well-vegetated streams and rivers. Image: L. Catchick, wikipedia, CC BY 3.0 (original here).

There’s a lot to say about heliornithids – their biogeography and fossil record is confusing and fascinating – but here I want to focus on one particularly interesting aspect of their biology. Namely, that the tropical American Sungrebe Heliornis fulica (sometimes called the American finfoot) has pouches, and uses these pouches in the protection and transportation of its young. The chicks are altricial (that is, unable to walk or look after themselves) and hatch after a ridiculously short incubation period of just 10-11 days. Incubation is carried out by both parents, but it’s the male alone who has the pouches and is able to transport the chicks (Bertram 1996).

Waitaminute… pouches? In a bird? How exactly do these structures work? What do they look like? And where are they located? Books and articles that mention the pouches generally say that there are two of them and that they’re under the wings, but you don’t get much more detail than that. The primary source of detailed information on what’s going on here is Miguel Álvarez del Toro’s 1971 article, a semi-legendary paper that most interested people are aware of due to the summarised description of its contents provided by Brian Bertram in his heliornithid chapter in Handbook of the Birds of the World, Volume 3. Bertram (1996) didn’t provide photos or diagrams, basically because those that exist are not good enough or of the right style for HBW. But Álvarez del Toro (1971) did.

Caption: yes, there are published photos of Sungrebe babies inside their father’s pouches. Or.. there’s one photo, anyway. Here it is, and it comes from Álvarez del Toro’s 1971 paper. Image: Álvarez del Toro (1971).

A far older publication – one of Prince Maximilian of Wied-Neuwied’s volumes of his Beiträge zur Naturgeschichte von Brasilien – also includes discussion and description of sungrebe pouches. I haven’t seen this reference but it was cited by Álvarez del Toro (1971).

Caption: pouch configuration, with feathering removed and chick in place, in the male Sungrebe, as illustrated by Álvarez del Toro (1971). This was drawn directly from a specimen. Image: Álvarez del Toro (1971).

If – for now – we ignore feathers, the pouches are essentially shallow, oval pockets formed by muscular pleats of skin that extend along the side of the chest. The bird appears to have some muscular control over the shape and turgidity of the pleats (Álvarez del Toro (1971). A single chick can fit in each pouch, but it would likely fall out if the structure consisted of skin folds and a recessed area alone. Here, it seems, is where the feathers come in: a number of long, curved feathers grow upwards and backwards from the lower part of the side of the chest and form a feathery outer wall, this now meaning that the recess becomes a secure pouch. And let me state again that all of this is exclusive to males: females do not have any of these anatomical peculiarities.

Caption: Álvarez del Toro’s (1971) illustration of the pouch, now with the feathering in place. The feathers form a lateral wall to the pouch and keep the chick in place. Image: Álvarez del Toro (1971).

When are the pouches used? I used to think that they were only there for emergency reasons (say, nest invasion by a predator), and possibly not even used by every sungrebe father. This appears to be incorrect. Álvarez del Toro (1971) disturbed a nesting male sungrebe and then saw it both swimming and flying with “two tiny heads sticking out from the plumage of the sides under the wings”, so this might support the idea of ‘emergency’ function. But his conclusion overall was that the chicks are (somehow) placed within the pouches immediately after hatching, kept there for days as they grow their plumage and become more capable, and are fed and kept clean by the male all the while: “While carrying the young, the male reaches beneath the wing to feed them and remove the droppings” (Álvarez del Toro’s 1971, p. 86).

Caption: Heliornis, as illustrated for the HUGE bird section of the in-prep The Vertebrate Fossil Record. Yes, there are fossil heliornithids (or… claimed heliornithids, anyway). Progress on this book can be viewed here at my patreon. Image: Darren Naish.

And that, as far as I can tell, about sums up everything we know. The exact and precise details as goes what’s going on here haven’t been worked out, and a full and detailed study is still required. Presumably that will happen eventually. Are these structures definitely a novelty of Heliornis, or are they more widespread, and are there similar, related or relevant structures elsewhere in related species? It really doesn’t seem that there are, but Bertram (1996) noted that it might be difficult to say for sure given that much of our anatomical knowledge on these animals (as in, obscure gruiforms in general) comes from dried skins.

Those of you familiar with the arcane ornithology literature will know that the transportation of chicks by adults has been mooted for a reasonable range of species, including nightjars, woodcocks and other waders, various galliforms, anseriforms and others (see Ad Cameron’s illustrations below - the nightjar illustrations are almost certainly fanciful - from Perrins (1992)). Most of these cases are likely or almost definitely erroneous… and they don’t involve pouches…. but not all are. Jacanas definitely transport their babies by clasping them with their wings, but they can’t do this while flying.

Caption: ornithologists spent decades arguing over whether nightjars (these are European nightjars Caprimulgus europaeus) and Eurasian woodcocks Scolopax rusticola carry their eggs and/or chicks in flight. It now seems that woodcocks do do this (as do other waders, like some shanks), but that nightjars seemingly don’t. Image: Ad Cameron, in Perrins (1992).

I’d like to finish this article by taking you on a weird, speculative tangent in the vein of All Yesterdays (Conway et al. 2012). Regular readers of this blog will know that I often write about extinct dinosaurs, and – on occasion – about speculations pertaining to the behaviour or anatomy of extinct dinosaurs. If we were asked (as we occasionally are) how likely it might be that extinct dinosaurs – say, for example, hadrosaurs or therizinosaurs – had pouches in which they could carry and transport their young, we would typically respond by noting the total lack of evidence that might support such a possibility, and the sheer improbability of such a thing given the anatomy of the living animals that ‘bracket’ the relevant fossil animals on the family tree.  There are no pouches in crocodylians or those living birds that diverged earliest in bird history, nor are there indications of them in stem-members of these lineages.

Caption: there are no pouches here, but at least we have a speculative scene where an adult maniraptoran (presumably a dromaeosaur) is carrying its young. Image: Alex Sone (original here).

But novelty does arise – phylogenetic brackets can be violated, as I’ve said, to the amusement of some, at least once here in the past – and there’s no way we’d predict the anatomy of Heliornis if we only knew of it as a fossil. Could, then, that most bizarre novelty – a pouch for carrying babies – have arisen elsewhere in dinosaurs? To suggest such would be a grotesque and baseless novelty of the worst kind. Yup. Did I mention All Yesterdays?

My thanks to the anonymous colleague who kindly provided me with the key piece of literature that allowed the production of this article. And thanks to those who contributed to the poll at the Tetrapod Zoology facebook group and thereby forced this article to the top of the list.

Caption: put ‘A really weird bird’ into a poll … and, wow, people really like really weird birds. This is a screengrab from a facebook poll.

Thanks to those supporting this work – and the very blog itself – via pledges at patreon. You can support what I do and see works-in-prep behind the scenes, via pledges as small as $1 per month.

Refs - -

Álvarez del Toro, M. 1971. On the biology of the American finfoot in southern Mexico. Living Bird 10, 79-88.

Bertram, B. C. R. 1996. Family Heliornithidae (finfoots). In del Hoyo, J., Elliott, A. & Sargatal, J. (eds) Handbook of the Birds of the World, Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona, pp. 210-217.

Conway, J., Kosemen, C. M., Naish, D. & Hartman, S. 2012. All Yesterdays: Unique and Speculative Views of Dinosaurs and Other Prehistoric Animals. Irregular Books.

Garcia-R, J. C., Gibb, G. C. & Trewick, S. A. 2014. Deep global evolutionary radiation in birds: diversification and trait evolution in the cosmopolitan bird family Rallidae. Molecular Phylogenetics and Evolution 81, 96-108.

Perrins, C. 1992. Bird Life: An Introduction to the World of Birds. Magna Books, Liecester [sic].

Erroll Fuller’s The Passenger Pigeon

Most readers of this blog will be familiar with Erroll Fuller and the huge quantity he has published on recently extinct birds. His books typically combine a discussion on the biology, history and extinction of the species, a section on existing specimens (as in, museum mounts and skins and eggs and so on), and some good coverage of the animal’s appearances in art and popular culture.

Cover, featuring John James Audubon’s illustration from The Birds of North America. Credit: fair use.

Fuller’s 2015 The Passenger Pigeon does all this and more, and is an extremely well-illustrated, popular review of what we know of this species. The Passenger pigeon Ectopistes migratorius is/was a long-tailed, swift-flying pigeon, famous for existing in nomadic flocks of billions by the time Europeans began colonising North America. How the birds came to be so phenomenally abundant, whether this was an ephemeral or long-lived phenomenon, and how linked this was to human-caused habitat change are good questions and there are reasons for thinking that a population of billions was not a pre-Holocene condition (e.g., Mann 2011).

Juvenile, male and female Passenger pigeon, as illustrated by Louis Agassiz Fuertes in 1910. Credit: public domain, original here.

Fuller’s The Passenger Pigeon is not a gargantuan magnum opus like his The Great Auk (Fuller 1999). It’s far smaller (25 x 19 cm) and slimmer (177 pages). It includes an extraordinary number of photos, paintings and drawings, and indeed is a very attractive volume. Numerous black and white photos, mostly taken of captive birds in the early 1900s, depict the animals in life. There are photos of Martha (fabled ‘last of the passenger pigeons’) too, and reproductions of many paintings and other artworks.

The Passenger Pigeon is not an academic tome with technical citations and any extended discussion of thoughts on this bird’s evolution or biology. But it’s a good book nonetheless and I definitely recommend it for anyone interested in pigeons and/or in recently extinct birds.

The Passenger Pigeon is not as huge and impressive as Fuller’s The Great Auk book, but that’s ok. Credit: fair use.

Errol Fuller. 2015. The Passenger Pigeon. Princeton University Press (Princeton and Oxford), pp. 177. ISBN 978-0-691-16295-9. $29.95. Hardback, index, refs. Here at amazon, here at amazon.co.uk, here from the publishers.

 For previous TetZoo articles on pigeons and kin, see…

• The detachable tails of pigeons, September 2008

• Are parrots actually pigeons?, May 2009

• Giant club-winged pigeons and ninja ibises: clubs, spurs, spikes and claws on the hands of birds (part III), February 2011

• Sunbathing birds, August 2011

• The war on parasites: the pigeon’s eye view, the oviraptorosaur’s eye view, August 2012

• Footless urbanite pigeons, September 2014

• Voyeurism and Feral Pigeons, June 2015

• The Asian Dove That Ate Europe Alive, January 2017

• Pigeons and Doves 101, March 2018

Refs - -

Fuller, E. 1999. The Great Auk. Erroll Fuller, Southborough, Kent.

Mann, C. C. 2011. 1491: New Revelations of the Americas before Columbus. Vintage, New York.

Aldrovandi’s Monstrous Rooster, a 16th Century Dino-Chicken

Chickens are remarkable animals, and I’ve written about them a few times at TetZoo before, albeit always too briefly (see links below). I really need to write about them at length at some point; I actually worked for a few years as a specialist chicken researcher and gathered a lot of interesting information on these birds. Anyway… here, I want to talk about one chicken in particular: a famous individual that has been mentioned several times in the recent literature (e.g., Kaiser 2007). Namely: Aldrovandi’s monstrous rooster.

Original image of Aldrovandi’s monstrous rooster, from volume 2 of his Ornithologia. Credit: scan archived by University of Oregon (original here).

Ulisse Aldrovandi (1522-1605) was an Italian philosopher, physician and naturalist who’s most frequently mentioned for his three-volume Ornithologia of 1600. Therein, he wrote a lot about chickens, and part of his text covers mutants and monsters, predominantly conjoined chickens and chickens with extra limbs. My Latin is not that hot (err… Caecilius est pater), so it’s fortunate that Fernando Civardi transcribed, and Elio Corti translated, the chicken section of this work such that it’s today available to English readers. The resulting volume, published in 2009, is titled The Chicken of Ulisse Aldrovandi (Corti & Civardi 2009). It’s a great read if you like chickens.

For completeness I should note that Aldrovandi’s chicken text was actually translated beforehand (in 1963) by another worker (L. R. Lind) (Aldrovandi 1963). This version is said to be plagued with translation errors (hey, not my opinion) and hence is not preferred by specialists.

The cover of Lind’s 1963 translation of Aldrovandi’s chicken text. What’s that thing on the cover? Well… that’s a whole ‘nother story. Credit: amazon.

To return to the monstrous rooster, the book includes a fine depiction of it as well as a good paragraph of description and interpretation. Aldrovandi himself observed this remarkable bird, alive, in the collection of Francesco Medici – the Grand Duke of Tuscany – and described it as so shocking in appearance that “it struck fear into brave men with its terrifying aspect”. It was blackish overall with white bases to its feathers, and its feathers are said to have looked scale-like. Given that clean-edged, metallic feathers in many gallinaceous birds can look superficially scale-like (one of the best examples being the feathering of male Green peacock Pavo muticus, sometimes called the dragonbird), this is perhaps not as surprising as it might sound.

There are a great many amazing gallinaceous birds, and here’s one of my favourites: the Green peacock. This is a captive individual at Tierpark Berlin. There’s an entire TetZoo article on this species: see links below. Credit: Markus Bühler, used with permission .

The monstrous rooster did not possess a conventional fleshy comb and paired wattles but had feathers in their place: a large feathery crest projected from the top of the head and two spines – interpreted by Aldrovandi as feather quills lacking barbs – pointed upwards and outwards from the forehead, “as if they were two horns”. Tufts of long, bristle-like structures emerged from either side of the bill (close to the nostrils) and from the back of the neck as well. The legs were feathered down to the ankles and the feet appear not to have been remarkable. The bird appears to have been tall and large, based on the illustration (though no scale was provided). A colourised interpretation of the animal was produced by Corti & Civardi (2009).

Cover of Corti & Civardi (2009), showing a colourised version of Aldrovandi’s monstrous rooster. Oh to see such a bird in life. Credit: Corti & Civardi (2009).

Finally, the most remarkable feature was the tail. It emerged from a whitish, rounded mass of feathers, and was long, slender, fleshy and pale blue. A mass of feathers formed a tuft (Aldrovandi called it a “flock”) at the tip. This tail reminded Aldrovandi of that of “quadrupeds”, predumably meaning lizards or mammals like rats or cats. Here I would remind you that a maniraptoran with a long tail ‘should not’ – so we think based on fossils – have a tail superficially recalling that of a lizard, but instead have a resplendently feathered one. The weirdness here perhaps indicates that the embryological development of this animal’s tail was likely different from that of extinct long-tailed birds and other Mesozoic maniraptorans.

Indeed, this bird sounds so weird overall that I sometimes even wonder whether it really was a domestic chicken, and not a member of some other (presumably now extinct) gallinaceous bird. But I don’t think that this is really up there as a possibility: it really was a member of Gallus gallus.

So… wow. What are we to make of all this?

Agostino Carracci’s portrait of Ulisse Aldrovandi (1522-1605), physician, philosopher and naturalist. Credit: image in public domain, from wikipedia (original here).

For starters, what do we know about Aldrovandi? Well, quite a lot. He was a credible, well trained individual who had studied law, philosophy, mathematics and logic at university; he published on insects and other invertebrates and was even credited by Linnaeus as the ‘father of natural history’. He also wrote extensively about anomalous cases in zoology and medicine and collected enough of them that they were (posthumously) published in the 1640 volume Historiae Serpentum et Draconum and the 1642 Monstrorum Historia. His serpents and dragons book also includes a brief discussion of the monstrous rooster, but doesn’t add information relative to that included in his Ornithologia.

Damn, chickens are awesome. These birds belonged to a group living semi-wild on Madeira. Credit: Darren Naish.

What we can glean from Aldrovandi’s writings is that he lived within the ethnographic landscape of Renaissance Italy, by which I mean that he seemingly believed in things (like human-like monsters and mythical beasts of far-off lands) that we today know not to exist. But his writings on direct, specific cases show that he was not credulous or prone to endorsing half-truths. He was critical of stories about basilisks, for example (thought at the time to result from the production or brooding of eggs by roosters)*. Furthermore, his illustrations of known animals are often highly accurate, as you can see from the examples shared here. Indeed, his writings on other anomalous specimens – like the ‘Homuncio’ (a short-statured Indian man whose body was draped with massive fleshy growths) – have been interpreted as biologically accurate (Ruggieri & Polizzi 2003).

* For those curious, I’m not exploring the basilisk angle here; I have to avoid it for now. Constraints of time.

Aldrovandi was a skilled and accurate artist, and his illustrations of known species - familiar and foreign - are usually highly accurate, as is demonstrated by these chickens. His chicken text also includes several illustrations of curassows, and they’re all essentially accurate. Credit: Corti & Civardi (2009).

The major caveat here is that Aldrovandi’s text and illustration of the monstrous rooster were (so far as we can tell) produced some considerable time after his observation of the bird, in which case all sorts of discrepancies might have crept in. The possibility that it had been modified or fitted with an artificial tail is not out of the question, but can’t be tested and is just an idea I need to mention in passing. We do know of other cases whereby animals have been made to look remarkable to impress or dupe observers, after all.

But, all in all, I’m inclined to think that the case was genuine, and that a long-tailed mutant rooster really was observed at some point in the 1500s by an erudite young man.

If a ‘dino-chicken’ ever does come to pass, it should be awesome and beautiful — like a real chicken. Err, in which case I don’t think anyone will look at it and think of a connection with the Mesozoic maniraptorans it’s meant to evoke. Whatever. Credit: Rebecca Groom.

I will leave you with one final thought. Jack Horner’s ‘dino-chicken’ project seeks to create a mutant fowl with a long, bony tail and other ‘ancestral’ features, all brought into existence via genetic and embryological modification. And research underpinning such efforts has already been published (Rashid et al. 2018). Was Aldrovandi’s rooster a demonstration that some of these developmental changes can occur without modern, deliberate modification? In other words, could it have been a real, ‘natural’ dino-chicken; one that existed four-hundred years before our time? If only the body, or skeleton, of this amazing bird had been preserved.

For other TetZoo articles linked to things mentioned here, see… (note: TetZoo ver 2 articles - the ScienceBlogs ones - are now appearing without their images, yay!)…

• How to prevent cannibalism in pheasants, March 2010

• The snood of the turkey, the wires and rackets of the motmot, the face of the rook, February 2011

• Chickens, 2012, April 2012

• Turkeys vs peafowl, the great debate, January 2013

• The other turkey, January 2013

•  The other peacock, January 2013

Refs - -

Aldrovandi, U. 1963. Aldrovandi on Chickens. Translated by L. R. Lind. University of Oklahoma Press, Norman, OK.

Corti, E. & Civardi, F. 2009. The Chicken of Ulisse Aldrovandi. www.summagallicana.it

Kaiser, G. 2007. The Inner Bird: Anatomy and Evolution. University of British Columbia, Vancouver.

Rashid, D. J., Surya, K., Chiappe, L. M., Carroll, N., Garrett, K. L., Varghese, B., Bailleul, A., O’Connor, J., Chapman, S. C. & Horner, J. R. 2018. Avian tail ontogeny, pygostyle formation, and interpretation of juvenile Mesozoic specimens. Scientific Reports 8: 9014.

Ruggieri, M. & Polizzi, A. 2003. From Aldrovandi’s “Homuncio” (1592) to Buffon’s girl (1749) and the “Wart Man” of Tilesius (1793): antique illustrations of mosaicism in neurofibromatosis? Journal of Medical Genetics 40, 227-232.