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.

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.

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 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.

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.

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).

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 ).

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  ).

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 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.

TetZooniverse-Christmas-2018-tiny-from-Darren-Naish.jpg

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

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.

New Living Animals We Want to Find

As a regular denizen of the TetZooniverse, you may well remember the July 2017 article ‘Fossils We Want to Find’ in which I discussed a list of hypothetical fossil things that we might one day discover but haven’t yet. Wouldn’t it be fun to do the same sort of thing with extant species; that is, with discoveries pertaining to living, breathing animals? Over at the Zoology for Enthusiasts facebook group (a spinoff of the Tetrapod Zoology facebook group), Jordan Fryer suggested doing exactly this, and consequently people have been coming up with their own suggested living animals that might await discovery. Because this seemed like a lot of fun (and a chance to discuss some really neat and unusual stuff), I thought I’d give it a go.

The 2017 precursor to the article you’re reading here was all about fossil animals. It included this photo, which shows me in the act of discovering a dinosaur bone in the Moroccan Sahara. Image: Richard Hing.

The 2017 precursor to the article you’re reading here was all about fossil animals. It included this photo, which shows me in the act of discovering a dinosaur bone in the Moroccan Sahara. Image: Richard Hing.

Naturally, any list of this sort is horribly subjective, reflecting the interests and biases of the person compiling the list, but so be it. It also seems all too easy to turn any compilation into a ‘list of most discoverable cryptids’: for those of you who don’t know, I have a long-standing interest in cryptozoology and have published on it quite frequently (see Naish (2017) for starters). For the most part, I’ve not done this, though read on.

Many of my thoughts on mystery animals can be found in my   2017 book  Hunting Monsters   . I am not - sorry - much impressed by the case for such supposed animals as the mokele-mbembe, an artistic reconstruction of which is shown at right. Image: David Miller, in   Mackal (1987)  .

Many of my thoughts on mystery animals can be found in my 2017 book Hunting Monsters. I am not - sorry - much impressed by the case for such supposed animals as the mokele-mbembe, an artistic reconstruction of which is shown at right. Image: David Miller, in Mackal (1987).

I’ve also mostly excluded hypothetical discoveries that are inspired by the creatures of cryptozoology but could arguably be considered independent of the cryptozoological literature. In part this is because I don’t think they’re plausible or worth considering, but it’s also because they’re cliched and the opposite of original. So, no ‘living sauropods from the Congo’ or ‘living plesiosaurs in Loch Ness’, for example.

As for what I have selected: well, some of my suggestions are sillier than others, and some are perhaps not that interesting to non-specialists. But, whatever. Feel free to dissect my suggestions in the comments, and perhaps come up with your own.

Among my suggested ‘fossils we want to find’ are protobats (like the hypothetical examples shown at left, from Graham (2002)) and a good skeleton of the giant hominid  Gigantopithecus blacki . This ilustration of a lower jaw is from Simons & Ettel's (1970) magazine article. Images: Graham (2002), Simons & Ettel (1970).

Among my suggested ‘fossils we want to find’ are protobats (like the hypothetical examples shown at left, from Graham (2002)) and a good skeleton of the giant hominid Gigantopithecus blacki. This ilustration of a lower jaw is from Simons & Ettel's (1970) magazine article. Images: Graham (2002), Simons & Ettel (1970).

A habitually bipedal, large, non-human hominid. Whatever you think of all those stories, anecdotes and sightings about bigfoot, yeti, almas, orang-pendek, yowie and so on and on, the fact remains that the discovery of a large, bipedal non-human hominid – whether it be a pongine, hominine, or member of another hominid lineage – would be a huge deal. It would not just be one of the most newsworthy creatures to ever be discovered; it would also have enormous ramifications for our understanding of hominid evolution and potentially the human condition itself.

Are crypto-hominids a cultural phenomenon more than a zoological one? I’ve argued for both possibilities at different times. Whatever… for the purposes of the article you’re reading now, I hope we can agree that the discovery of such an animal would be high on any hypothetical ‘wants’ list. Image: Darren Naish.

Are crypto-hominids a cultural phenomenon more than a zoological one? I’ve argued for both possibilities at different times. Whatever… for the purposes of the article you’re reading now, I hope we can agree that the discovery of such an animal would be high on any hypothetical ‘wants’ list. Image: Darren Naish.

It would also – if relating to North America or northern Eurasia in particular – very likely have a significant impact on economy, land management and land use in those regions… or, you’d hope it would, anyway (who knows, given the current state of environmental protection in the USA). The hypothetical discovery of such an animal would also be regarded by many as one of the biggest ‘wins’ ever scored against ‘establishment science’, and thus could well be a bad thing (viz, “if scientists were wrong about this, what else could they be wrong about?”). And I’ll stop there before we dive into a rabbit-hole of conspiracy theories and coverups.

A big, flightless passerine. The majority of living bird species – over 60% of them – are passerines, or perching birds. This is the great group that includes crows, thrushes, warblers, finches, sparrows and so many others. For all their success, wide distribution and diversity, passerines are generally quite samey. There are no big, long-legged wading passerines, or heavy-bodied diving passerines or flightless running passerines, for example. Why this is so remains mysterious: passerines didn’t take to those niches because… well, they just didn’t. Does this mean that they couldn’t? As usual, we can come up with a few reasons as to why they were ‘constrained’ in evolutionary potential, but any one of those reasons could be overturned by some evolutionary deviant that refuses to pay attention to the rules.

Passerine birds are diverse, to a degree… here’s just a sample of their diversity. This is part of a giant montage that’s being built for   my in-prep textbook The Vertebrate Fossil Record  . Image: Darren Naish.

Passerine birds are diverse, to a degree… here’s just a sample of their diversity. This is part of a giant montage that’s being built for my in-prep textbook The Vertebrate Fossil Record. Image: Darren Naish.

And thus I submit that a particularly large, wholly flightless, cursorial passerine should make itself known to the world. It should be a record-holder as goes size, but not necessarily be that much bigger than the largest known passerines (like lyrebirds and ravens): I’m talking about a bird that weighs 3-5 kg and is thus similar in size to a large chicken. It should be a big, long-legged rail-babbler, quail-thrush or similar, and hence be a denizen of Wallacea or nearby.

Eupetes , the Malaysian rail-babbler. A hypothetical big, flightless passerine should be a close relative of this bird. Image: Francesco Verronesi, CC BY-SA 2.0 ( original here ).

Eupetes, the Malaysian rail-babbler. A hypothetical big, flightless passerine should be a close relative of this bird. Image: Francesco Verronesi, CC BY-SA 2.0 (original here).

A few recently extinct, island-dwelling passerines were flightless, so we do know that passerines have the evolutionary potential to follow this pathway. Such species (a bunting and a few New Zealand wrens… and possibly a few others) were all small (less than 40 g).

A western Asian giant salamander. Giant salamanders (cryptobranchids) are restricted today to eastern Asia (where Andrias occurs) and North America (where Cryptobranchus occurs). Hunting, human disturbance, habitat loss and deterioration, climate change and other issues are putting them into perilous decline, right at the same time as we’re discovering that some of them are species complexes. They were more widespread in the past than they are today, since fossils show that Andrias salamanders were widespread across Europe and Asia between about 28 and 2 million years ago.

An Asian giant salamander ( Andrias ) photographed in captivity. Record-holding specimens of  Andrias  can be 1.8 m long and exceed 60 kg, and some extinct species reached even larger sizes. Image: Markus Bühler.

An Asian giant salamander (Andrias) photographed in captivity. Record-holding specimens of Andrias can be 1.8 m long and exceed 60 kg, and some extinct species reached even larger sizes. Image: Markus Bühler.

While there are very good reasons for the decline and extinction of the animals in the areas concerned, some of the regions where they formerly occurred still have what look like suitable habitat today and are sparsely populated by people. Furthermore, extinct giant salamanders weren’t all denizens of fast-flowing, highly oxygenated streams like those inhabited by the modern populations. Some inhabited ponds and lakes. Ergo: I would really, really like there to be a west Asian cryptobranchid that comes from a habitat considered weird for the other living members of the group. And it doesn’t have to be a giant of 2 metres or more. A hellbender-sized species of 70 cm or so will do fine thank you very much.

Some extinct cryptobranchids - this is Zdeněk Burian’s reconstruction of  Andrias scheuchzeri  - inhabited European ponds and lakes. I’ve previously criticised this image for showing the animal as terrestrial. Since then, the proposal has been made that some extinct cryptobranchids (albeit not  A. scheuchzeri ) were significantly more terrestrial than living species. Image: (c) Zdeněk Burian.

Some extinct cryptobranchids - this is Zdeněk Burian’s reconstruction of Andrias scheuchzeri - inhabited European ponds and lakes. I’ve previously criticised this image for showing the animal as terrestrial. Since then, the proposal has been made that some extinct cryptobranchids (albeit not A. scheuchzeri) were significantly more terrestrial than living species. Image: (c) Zdeněk Burian.

Again, this is an area of special interest to cryptozoologists, since there have been occasional suggestions that stories, engravings and such from western Asia might reflect folk knowledge of unusually big salamanders in the region. In reality, the images and stories concerned are super-ambiguous and more likely refer to otters and god knows what else.

At left:  Andrias  skull. Image: Darren Naish. At right: Japanese giant salamander ( A. japonicus ) illustration by Y. de Hoev from 1887. Image: Y. de Hoev, public domain ( original here ).

At left: Andrias skull. Image: Darren Naish. At right: Japanese giant salamander (A. japonicus) illustration by Y. de Hoev from 1887. Image: Y. de Hoev, public domain (original here).

A living albanerpetontid. Everyone knows that there are three main groups of living amphibian: caecilians, salamanders and anurans (frogs and toads). But until (geologically) recently, there was a fourth group: the albanerpetontids, sometimes termed albies by those who work on them. Albanerpetontids were geographically widespread, their range including Eurasia, northern Africa and North America, and they were geologically long-lived too. The oldest are from the Middle Jurassic while the youngest are… well, we’ve known of Miocene fossil albanerpetontids for decades, have known of Pliocene specimens since 2005 (Venczel & Gardner 2005), and now know that at least one species persisted into the Pleistocene (Villa et al. 2018). The fact that their fossil record has been creeping towards the Recent means that the possibility of fossil and even extant Holocene specimens being discovered isn’t ridiculous, especially given the small size of these animals and hence tiny size of their bones.

New salamander species are occasionally discovered in Europe and Asia even now. It would be amazing if an animal suspected to be a ‘new salamander’ one day turned out to be a living albanerpetontid. These reconstructions were published by McGowan & Evans (1995). They might have erred in implying that the scales would be externally visible as shown here; more likely is that they were concealed by epidermis, as in other scaly fossil amphibians. Image: McGowan & Evans (1995).

New salamander species are occasionally discovered in Europe and Asia even now. It would be amazing if an animal suspected to be a ‘new salamander’ one day turned out to be a living albanerpetontid. These reconstructions were published by McGowan & Evans (1995). They might have erred in implying that the scales would be externally visible as shown here; more likely is that they were concealed by epidermis, as in other scaly fossil amphibians. Image: McGowan & Evans (1995).

To be frank, a live albanerpetontid wouldn’t be a particularly spectacular animal: it would be a tiny, slim, salamander-like amphibian less than 10 cm long, and it wouldn’t be much fun to watch since it would spend most of its time hiding and burrowing in leaf litter. But among herp-nerds it would be a huge deal. Live albanerpetontids were scaly-skinned (though the scales were not necessarily visible externally), with eyelids, and with adaptations in the snout, skull-roof, neck and body shape linked to head-first burrowing (McGowan & Evans 1995).

An artistic reconstruction of a live albanerpetontid…   produced for my in-prep The Vertebrate Fossil Record  . Image: Darren Naish.

An artistic reconstruction of a live albanerpetontid… produced for my in-prep The Vertebrate Fossil Record. Image: Darren Naish.

A Eurasian palaeognath. Palaeognaths are the big, flightless ratites (ostriches, emus and so on), the superficially gamebird-like, flight-capable tinamous, and their extinct relatives. A huge amount has been written about the evolutionary history and biogeography of these birds, since their distribution is curious and has resulted in all kinds of different models about how they might have spread around the world. I’ve written about this issue at length on previous occasion (the articles concerned being famous for generating the longest-ever comment threads in the history of TetZoo… though all of this is mostly wasted now, what with SciAm’s paywalling of the site, sigh). Living palaeognaths are absent from Eurasia, despite the former present in the region of ancient, flight-capable Paleogene taxa, extinct ostriches and others.

As this map shows, modern palaeognaths occurred everywhere until recently (except Antarctica) with the exception of northern North America and the cooler parts of Eurasia. Extinctions across Eurasia, Madagascar and New Zealand of course saw the disappearance of various members of the group. Image: Darren Naish.

As this map shows, modern palaeognaths occurred everywhere until recently (except Antarctica) with the exception of northern North America and the cooler parts of Eurasia. Extinctions across Eurasia, Madagascar and New Zealand of course saw the disappearance of various members of the group. Image: Darren Naish.

The fact that Paleogene Europe was home to many bird groups that no longer occur there but are now denizens of tropical regions elsewhere leads me to hope for a living palaeognath – a tinamou- or bustard-sized species – that descends directly from archaic Paleogene taxa and now lives in the Asian tropics. It should be a cryptic generalist with barred plumage and a mid-length bill and a reduced flight ability.

A gigantic, predatory, limbed amphisbaenian. Regular readers of TetZoo might know that I really like amphisbaenians: the mostly limbless, bullet-headed ‘worm lizards’ of the American tropics, Africa, and parts of southern Europe and western Asia. Amphisbaenian evolutionary history and biogeography has become increasingly complex in recent years as we’ve learnt a bunch of new stuff about their fossil history, genetics and anatomy. Among the weirdest of amphisbaenians are the ajolotes (or bipedids), the only extant group to possess limbs. These limbs are not small stumps or flaps (as they are in some other near-limbless, serpentine squamates) but well-developed, clawed forelimbs. According to some phylogenetic models, ajolotes are not the sister-group to limbless amphisbaenians but deeply nested within the limbless clade (Conrad 2008, Videl et al. 2008), in which case their limbedness – if you will – perhaps evolved from limbless ancestors. Add to this the fact that some amphisbaenians are robust-jawed, short-faced predators of vertebrates that ambush prey from beneath the surface and bite chunks from the bodies of surface-dwelling mammals and reptiles.

Bipes , an ajolote of Mexico (they might occur in parts of the USA as well). Three extant species are recognised. Image: Darren Naish.

Bipes, an ajolote of Mexico (they might occur in parts of the USA as well). Three extant species are recognised. Image: Darren Naish.

So then… where oh where are the giant, limbed, robust-skulled, vertebrate-eating amphisbaenians? By ‘giant’, I am not talking about a graboid-sized monster of several metres (though that would be nice), but a more reasonable animal of a mere 1.5 metres or so. Easily the stuff of nightmares. They could inhabit warm regions of any continent.

Carl Gans’s illustration of a burrowing ajolote, showing how the large, well-clawed forelimbs function in propulsion. This is clearly a Five-toed worm lizard  Bipes biporus ; the other extant species have four and three digits, respectively. Image:   Gans (1974)  .

Carl Gans’s illustration of a burrowing ajolote, showing how the large, well-clawed forelimbs function in propulsion. This is clearly a Five-toed worm lizard Bipes biporus; the other extant species have four and three digits, respectively. Image: Gans (1974).

Is there any reason to think that gigantic, predatory, limbed amphisbaenians might actually exist and await discovery? Nope. But I wish it were so. Regular readers might recognise that such creatures are denizens of the alternative-timeline Earth of the Squamozoic, but I’m sure that that’s coincidental.

What would a gigantic, predatory, limbed amphisbaenian look like? Like this, of course. Image: Darren Naish.

What would a gigantic, predatory, limbed amphisbaenian look like? Like this, of course. Image: Darren Naish.

An African or west Eurasian, long-beaked river dolphin. On several occasions within the history of odontocete cetaceans (‘toothed whales’), lineages have moved into brackish and estuarine environments, and eventually made the transition to committed freshwater life. There are the Asian Platanista species, the recently extinct Lipotes of China, and the tropical American Inia species. Once united within Platanistoidea and thought to be close kin, we know today that these animals represent at least three separate transitions to the freshwater environment (the term Platanistoidea is now restricted to the Platanista lineage alone). In addition, members of other groups – I’m thinking of the delphinid Orcaella – occur in rivers within parts of their range. There’s also a fossil beaked whale that might be indicative of freshwater specialisation in yet another odontocete group (Mead 1975).

River dolphins are pretty special looking. This is a Ganges river dolphin ( Platanista gangetica ). Image: Zahangir Alom / Marine Mammal Commission / National Oceanic and Atmospheric Administration, public domain ( original here ).

River dolphins are pretty special looking. This is a Ganges river dolphin (Platanista gangetica). Image: Zahangir Alom / Marine Mammal Commission / National Oceanic and Atmospheric Administration, public domain (original here).

In view of all this, why aren’t there river-dwelling dolphins in Africa, Europe or western Asia? Again, the answer seems to be… there just aren’t. A few fossil taxa suggest that such animals might have evolved if things had gone another way (there are fossil platanistoids from the Caucasus, for example). But I humbly submit that the great river systems of tropical Africa, the Tigris-Euphrates system of western Asia and the Danube, Po, Ebro, Dniester and others of southern Europe would be much improved if only we knew of their endemic riverine dolphins. I’m talking about a true riverine specialist, convergent with Inia and Platanista, with a long beak, spike-like teeth, reduced eyesight, the works. And if you want to play fast and loose with antiquarian literature and anecdote, there are references in the literature to ‘river dolphins’ in the Nile and there are even one or two eyewitness accounts from central Europe that describe long-beaked ‘dolphins’ seen in rivers and lakes.

If there are extant west Eurasian or African river dolphins, they should look like this. This is a hypothetical species, modelled on the American  Inia  and Asian  Platanista . Image: Darren Naish.

If there are extant west Eurasian or African river dolphins, they should look like this. This is a hypothetical species, modelled on the American Inia and Asian Platanista. Image: Darren Naish.

An endoparasitic tetrapod. Tetrapods have become parasites on several occasions. Vampire bats are parasites of birds and mammals, and it’s even been argued that some blood- and milk-eating human populations can be considered parasites of the mammals they rely on (though the mammals concerned are domesticated, so it’s complicated). Elsewhere among vertebrates, everyone knows about the parasitic catfishes that invade the gills of other actinopterygian fishes and even the urethras of mammals; less familiar is the fact that other actinopterygians can, on rare occasion, become trapped inside the bodies of other vertebrates and then make a successful living. Yes, you read that right. I have in mind the case where two Snubnosed or Pugnose eels Simenchelys parasitica were discovered living inside the heart of a mako shark (Caira et al. 1997; see also Eagderi et al. 2016). This eel is not – despite its name* – ordinarily an internal parasite: this was a case of facultative endoparasitism!

At left: a snubnosed eel found living inside the heart of a shark. Eels are not tetrapods, it’s true. But here’s evidence that aquatic vertebrates can become endoparasites. Image: Caira  et al . (1997). At right: an aquatic typhlonectid caecilian. Surely it’s only a matter of time before we discover an endoparasitic one of those as well. Image: Neil Phillips.

At left: a snubnosed eel found living inside the heart of a shark. Eels are not tetrapods, it’s true. But here’s evidence that aquatic vertebrates can become endoparasites. Image: Caira et al. (1997). At right: an aquatic typhlonectid caecilian. Surely it’s only a matter of time before we discover an endoparasitic one of those as well. Image: Neil Phillips.

There are all kinds of reasons why a tetrapod couldn’t become an endoparasite, respiration being high on the list. A hypothetical endoparasitic tetrapod would have to be small, with remarkable tolerance of unusual chemical and thermal conditions, with low oxygen requirements, and most likely with the ability to respire cutaneously or via gills. In other words, it should be the world’s weirdest caecilian. As if caecilians aren’t weird enough, I’d love there to be small, endoparasitic caecilians. Given that some caecilians are already aquatic gill-breathers that will consume the tissues of fish (exhibit A: the sequence from River Monsters where Jeremy Wade discovers swarming typhlonectid caecilians in the carcass of a large fish), I predict these animals to be aquatic, South American species that parasitise actinopterygians and aquatic mammals, like Inia the river dolphin.

* Snubnosed eels were given the name ‘parasitica’ because they opportunistically latch on to the bodies of larger fish and eat away at the flesh. They were not thought to ever be proper internal parasites prior to 1992.

And that’s where I’ll stop for now. I actually came up with a list containing numerous additional ‘wish list’ animals but time is against me. Maybe I’ll cover them in another article. Whatever, this was all a bit of fun and I hope you enjoyed it.

For TetZoo articles relevant to the issues covered here, see…

PS I’m going to stop linking to the SciAm run of TetZoo articles soon, because I cannot access them at all and they’re now all but useless. They all need to be relocated to an open-access site.

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 - -

Caira, J. N., Benz, G. W., Borucinska, J. & Kohler, N. E. 1997. Pugnose eels, Simenchelys parasiticus (Synaphobranchidae) from the heart of a shortfin mako, Isurus oxyrinchus (Lamnidae). Environmental Biology of Fishes 49, 139-144.

Conrad, J. 2008. Phylogeny and systematics of Squamata (Reptilia) based on morphology. Bulletin of the American Museum of Natural History 310, 1-182.

Eagderi, S., Christiaens, J., Boone, M., Jacobs, P. & Adriaens, D. 2016 Functional morphology of the feeding apparatus in Simenchelys parasitica (Simenchelyinae: Synaphobranchidae), an alleged parasitic eel. Copeia 104, 421-439.

Gans, C. 1974. Biomechanics: An Approach to Vertebrate Biology. J. B. Lippincott Company, Philadelphia, Toronto.

Graham, G. L. 2002. Bats of the World. St. Martin’s Press, New York.

Mackal, R. P. 1987. A Living Dinosaur? In Search of Mokele-Mbembe. E. J. Brill, Leiden.

McGowan, G. J. & Evans, S. E. 1995. Albanerpetontid amphibians from the Cretaceous of Spain. Nature 373, 143-145.

Mead, J. G. 1975. A fossil beaked whale (Cetacea: Ziphiidae) from the Miocene of Kenya. Journal of Paleontology 49, 745-751.

Naish, D. 2017. Hunting Monsters: Cryptozoology and the Reality Behind the Myths. Arcturus, London.

Simons, E. L. & Ettel, P. C. 1970. GigantopithecusScientific American 222 (1), 77-84.

Venczel, M. & Gardner, J. D. 2005. The geologically youngest albanerpetontid amphibian, from the Lower Pliocene of Hungary. Palaeontology 48, 1273-1300.

Vidal, N., Azvolinsky, A., Cruaud, C. & Hedges, S. B. 2008. Origin of tropical American burrowing reptiles by transatlantic rafting. Biology Letters 4, 115-118.

Villa, A., Blain, H.-A. & Delfino, M. 2018. The Early Pleistocene herpetofauna of Rivoli Veronese (Northern Italy) as evidence for humid and forested glacial phases in the Gelasian of Southern Alps. Palaeogeography, Palaeoclimatology, Palaeoecology 490, 393-403.

The Tet Zoo Guide to Mastigures

Among my favourite lizards are the Uromastyx agamids, variously termed mastigures, dabbs, dabs, dhubs, spinytails, spiny-tailed agamas, spiny-tailed lizards or thorny-tailed lizards. In the pet trade they’re often called ‘uros’. Here, I’ll be calling them mastigures.

A large mastigure is a fine, handsome, happy-looking lizard. The dark overall colour and yellow dorsal occellations show that this captive specimen is a Moroccan mastigure  Uromastyx acanthinurus . Image: Darren Naish.

A large mastigure is a fine, handsome, happy-looking lizard. The dark overall colour and yellow dorsal occellations show that this captive specimen is a Moroccan mastigure Uromastyx acanthinurus. Image: Darren Naish.

Mid-sized for lizards (25 cm in total length is typical, though read on), they’re rather chunky, short-headed and wide-bodied with a proportionally short, broad tail that’s covered in 10 to 30 transverse, parallel rows of posterodistally projecting spines. The rows have a ring-like form and (rather confusingly) are typically called whorls. The tail is said to function as a ‘burrow blocker’ and also to be lashed from side to side when deterring would-be attackers. Enlarged, thorn-like scales are also present on the hindlimbs of some species. The head is short and deep by lizard standards and a neat feature is that the labial scales are large, serrated structures that sometimes look like external pseudoteeth.

Head detail of a captive  U. acanthinurus . Note the pseudoteeth-like upper labial scales. The white exudate around the nostrils is pretty typical: it's salt discharge and evidence of nasal salt excretion typical for desert-dwelling lizards. Image: Darren Naish.

Head detail of a captive U. acanthinurus. Note the pseudoteeth-like upper labial scales. The white exudate around the nostrils is pretty typical: it's salt discharge and evidence of nasal salt excretion typical for desert-dwelling lizards. Image: Darren Naish.

Mastigures are extremely variable in colour, ranging from almost black to almost white dorsally; areas of yellow and even bright orange are present in some species, sometimes forming eye-like markings, distinct spots large or small, or transverse bands. The head may be much darker than the rest of the animal, and sometimes the tail is different in colouration too. Adding to this complexity is that individuals change colour according to temperature and time of day. The tail is variable in size: it's similar in length to the body in most species but is very short and broad in a few species, most notably the Omani spiny-tailed lizard or Thomas's mastigure U. thomasi.

A captive  U. thomasi . The complex colouration - the facial banding in particular - is notable, as is the very short, broad, plump tail. This is a small mastigure with a total length of less than 15 cm. Recent surveys indicate that it is now extinct on mainland Oman - its type location - and is now unique to Masirah Island where local extinction has also occurred due to habitat destruction. There are anecdotal 2012 references to its persistence on the mainland, however. Image: Darren Naish.

A captive U. thomasi. The complex colouration - the facial banding in particular - is notable, as is the very short, broad, plump tail. This is a small mastigure with a total length of less than 15 cm. Recent surveys indicate that it is now extinct on mainland Oman - its type location - and is now unique to Masirah Island where local extinction has also occurred due to habitat destruction. There are anecdotal 2012 references to its persistence on the mainland, however. Image: Darren Naish.

The teeth are especially interesting: they’re short, low-crowned and fused to the jaw bones on their lingual (tongue) side, are largest at the back of the jaws, have crescentic shearing tips, and possess oblique wear facets that become so pronounced with age that entire teeth can be worn right down to the jaw (Cooper & Poole 1973). As you might guess, these animals do not possess regular tooth replacement of the sort we associate with reptiles (Robinson 1976). This is linked with a style of jaw movement (termed propaliny) where the lower jaw slides forwards to create a shearing bite when the jaws are closed (Throckmorton 1976). In the premaxillae, the upper central incisiforms are replaced by projecting structures that have been interpreted as bony pseudoteeth (Anderson 1999), though I don’t know if the histological work required to demonstrate this has been performed and they might be fused teeth.

The skull of  U. aegyptia , as scanned for The Deep Scaly Project and available  here . Note that the partially fused teeth are largest posteriorly. The mandible is deep, the front of the dentary is toothless and bony pseudoteeth are present in the premaxilla. Image:  Digimorph.

The skull of U. aegyptia, as scanned for The Deep Scaly Project and available here. Note that the partially fused teeth are largest posteriorly. The mandible is deep, the front of the dentary is toothless and bony pseudoteeth are present in the premaxilla. Image: Digimorph.

Mastigures occur throughout the steppes, deserts and semi-deserts of northern Africa, the Middle East and western and central Asia. They aren’t associated with dune-fields, instead inhabiting rocky or gravel-covered regions or areas with compacted sand. They use and build burrows that are sometimes 3 m long or so, though I would expect based on data from other burrow-digging reptiles that burrows at least twice as long might exist. ‘Colonial burrows’ have been mentioned in the literature (Anderson 1999), though I don’t know if this means that many burrows were located in close proximity or if the burrows were known to contain some or many lizards.

An Iraqi, Mesopotamian or Small-scaled spiny-tailed lizard  Saara loricata  (formerly  U. loricatus ), a mid-sized species of Iran and Iraq, as illustrated in one of Boulenger's 1885 catalogues of amphibians and reptiles kept in the collections of the British Museum. Image: Boulenger 1885.

An Iraqi, Mesopotamian or Small-scaled spiny-tailed lizard Saara loricata (formerly U. loricatus), a mid-sized species of Iran and Iraq, as illustrated in one of Boulenger's 1885 catalogues of amphibians and reptiles kept in the collections of the British Museum. Image: Boulenger 1885.

Around 15 extant species are recognised with Uromastyx, five of which have been named since 1990: U. maliensis Joger & Lambert, 1996, U. occidentalis Mateo et al., 1999 (or 1998), U. leptieni Wilms & Böhme, 2001 (or 2000…), U. alfredschmidti Wilms & Böhme, 2001 (or 2000…) and U. yemenensis Wilms & Schmitz, 2007. The total number of recognised species is a bit vague since some taxa are regarded as subspecies by some authors and as distinct species by others. An additional three Asian species have recently been removed from Uromastyx and placed in the resurrected genus Saara, first named by Gray in 1845 (Wilms et al. 2009). Saara species possess so-called intercalary scales between the spine whorls on the tail and molecular data finds them to be the sister-group to Uromastyx (Tamar et al. 2018).

Persian or Iranian spiny-tailed lizard  Saara asmussi , as illustrated in William Blanford's paper of 1876. This species occurs in Iran, southern Afghanistan and Pakistan. The  Saara  species were included within  Uromastyx  prior to Wilms et al. (2009). Image: Blanford 1876.

Persian or Iranian spiny-tailed lizard Saara asmussi, as illustrated in William Blanford's paper of 1876. This species occurs in Iran, southern Afghanistan and Pakistan. The Saara species were included within Uromastyx prior to Wilms et al. (2009). Image: Blanford 1876.

In recent years, Uromastyx mastigures have become increasingly common in the pet trade and it’s now normal to see them on show in places that sell pet reptiles. I have seen them in the wild while on fieldwork in the Sahara, but the individuals concerned were dead and I never have seen a live one in the wild.

A sadly deceased baby mastigure (probably  U. acanthinurus ), discovered in the Moroccan Sahara. Cause of death unknown. Note that the tail is fully developed and sports the full complement of tail spines, despite the animal's small size. Image: Darren Naish.

A sadly deceased baby mastigure (probably U. acanthinurus), discovered in the Moroccan Sahara. Cause of death unknown. Note that the tail is fully developed and sports the full complement of tail spines, despite the animal's small size. Image: Darren Naish.

Biology and behaviour. Mastigures are omnivorous, but they’re (seemingly) essentially herbivorous as adults, only occasionally eating arthropods or smaller lizards. The presence of symbiotic gut flora has been demonstrated for some species (a feature seen elsewhere in agamids in the Hydrosaurus sailfin dragons). Their lifestyle requires their taking refuge in rock crevices or burrows when they’re not feeding, foraging, basking or interacting socially, a behavioural syndrome where a compressed body shape and defensive spiny tail are advantageous, and one that has evolved convergently in other iguanians – the American chuckwallas and ctenosaurs and Madagascan oplurines – and in the Australian Egernia skinks and in some African corylids (Pianka & Vitt 2003).

The tail of a deceased mastigure (probably  U. acanthinurus ), discovered in the Moroccan Sahara. Image: Darren Naish.

The tail of a deceased mastigure (probably U. acanthinurus), discovered in the Moroccan Sahara. Image: Darren Naish.

Herbivory in lizards works best at large size for the obvious reason of how much nutrition can be recovered (though it’s worth saying that there are many exceptions to this tendency: see Espinoza et al. 2004); it follows, then, that mastigures are relatively large compared to other agamids. I don’t know if there are any studies that do demonstrate this specifically, but the fact that most species are 25-45 cm long as adults does seem large, and the biggest species – the Egyptian or Leptien’s mastigure U. aegyptia – is positively enormous, reaching 75 cm on occasion and even more (specimens nearly 1 m long have been reported… can you imagine a mastigure this size? Amazing). It’s worth saying here that an especially large Paleogene lizard – Barbaturex from the middle Eocene of Myanmar, it perhaps reached 2 m in total – appears to be an especially close relative of Uromastyx (Head et al. 2013).

I was curious to know what a c 90 cm mastigure would look like compared to a person. The smaller of these silhouettes reveals the answer. Not as impressive as I was hoping. The larger lizard silhouette depicts the approximate size of the Eocene taxon  Barbaturex , though we don't know that it had spiny whorls on its tail as shown in the illustration. The human figure is 1.7 m tall. Image: Darren Naish.

I was curious to know what a c 90 cm mastigure would look like compared to a person. The smaller of these silhouettes reveals the answer. Not as impressive as I was hoping. The larger lizard silhouette depicts the approximate size of the Eocene taxon Barbaturex, though we don't know that it had spiny whorls on its tail as shown in the illustration. The human figure is 1.7 m tall. Image: Darren Naish.

Mastigures are oviparous, females laying clutches of 6-20 elliptical eggs within a burrow. The hatchlings stay within the burrow for a few weeks, possibly even for months. The mother remains in attendance across this time and her burrow-guarding behaviour might be a form of parental care (directed both at the eggs and the hatchlings). Given that these lizards possess a symbiotic gut flora, the babies are presumably coprophagous. I’ve seen this stated informally but am not aware of a study that demonstrates it. Remember that tetrapods that possess a symbiotic gut flora must obtain it from their parents, and thus must eat their parent's dung early in life. Mm-mm.

An Egyptian spiny-tailed lizard  U. aegyptia , as depicted in John Anderson's 1898 volume on the amphibians and reptiles of Egypt. Image: Anderson 1898.

An Egyptian spiny-tailed lizard U. aegyptia, as depicted in John Anderson's 1898 volume on the amphibians and reptiles of Egypt. Image: Anderson 1898.

Antiquity, taxonomy, biogeography. Having mentioned fossils, jaw fragments that appear to be from Uromastyx-like agamids (though not necessarily Uromastyx itself) are known from the Lower Eocene of Kyrgyzstan (Averianov & Danilov 1996) and hence establish an age of around 50 million years for this lineage. A number of Paleocene and Eocene lizards from Mongolia and China appear to be additional uromastycines. Rather younger, Oligocene fossils from the famous Jebel Qatrani Formation of the Fayum in Egypt’s Western Desert are sufficiently mastigure-like that they’ve been identified as ‘cf. Uromastyx’ (‘cf’ is an abbreviation of the Latin ‘confer’ and, when used in a taxonomic identification, basically means ‘we think that these fossils are so comparable to [insert taxon of interest] that they might belong to it, though we can’t be sure’). They date to the Lower Oligocene and hence are around 33 million years old (Holmes et al. 2010). There’s also a Lower Oligocene Uromastyx mastigure from France – yes, a European member of the group.

Just one of the many uromastycine fossil jaw fragments from the Lower Eocene of Kyrgyzstan descibed by Averianov & Danilov (1996). These fossils - and others - demonstrate the antiquity of this group within Eurasia and show that it didn't arrive in the region after its Miocene collision with Africa. The scales bars = 1 mm. Image: Averianov & Danilov (1996).

Just one of the many uromastycine fossil jaw fragments from the Lower Eocene of Kyrgyzstan descibed by Averianov & Danilov (1996). These fossils - and others - demonstrate the antiquity of this group within Eurasia and show that it didn't arrive in the region after its Miocene collision with Africa. The scales bars = 1 mm. Image: Averianov & Danilov (1996).

This antiquity is in keeping with the idea – made on the basis of their highly distinctive anatomy – that mastigures are ‘distinct enough’ from other agamids to be worthy of their own ‘subfamily’: Uromastycinae. This view derives support from those studies that have found or inferred mastigures to be a distinct lineage outside the clade containing all remaining crown-agamids (e.g., Frost & Etheridge 1989, Macey et al. 2000, Schulte et al. 2003, Pyron et al. 2013), and perhaps even outside the clade that includes chameleons and conventional agamids (Honda et al. 2000, Gauthier et al. 2012). That last result would push mastigure origins into the Cretaceous given amber fossils that seem to be stem-chameleons.

A phylogeny for agamids and their close kin, as recovered by Honda  et al . (2000). Mastigures and butterfly agamas form a clade, and both are outside the clade that includes chameleons and 'Agamidae' of tradition.   Like all of these sorts of diagrams, this was produced for my in-prep Vertebrate Fossil Record book, progress on which can be seen here.   Image: Darren Naish.

A phylogeny for agamids and their close kin, as recovered by Honda et al. (2000). Mastigures and butterfly agamas form a clade, and both are outside the clade that includes chameleons and 'Agamidae' of tradition. Like all of these sorts of diagrams, this was produced for my in-prep Vertebrate Fossil Record book, progress on which can be seen here. Image: Darren Naish.

Oh, you want Cretaceous stem-mastigures? In 2016, Apesteguía et al. (2016) described Jeddaherdan aleadonta from the Cenomanian of Morocco, and concluded that both this taxon and Gueragama sulamericana from the Upper Cretaceous of Brazil – both represented by partial lower jaws – are exactly that. Fossil evidence does, therefore, now back up the idea that these lizards were in existence before the end of the Cretaceous, and that acrodonts* (and thus iguanians more generally) had evolved at least some of their variation before the Cenozoic.

* Acrodonts (properly Acrodonta): the iguanian lizard clade that includes chameleons and agamids. They are named for their acrodont teeth: that is, those fused to the jawbones (though this condition is not fully developed across all members of the clade, and note that there are acrodont reptiles that are not part of Acrodonta).

The Cretaceous uromastycine  Jeddaherdan aleadonta  is known from the chunk of lower jaw shown here, depicted within a silhouetted skull of  Uromastyx . The scale bar is in mm. Image: Apesteguía  et al . (2016).

The Cretaceous uromastycine Jeddaherdan aleadonta is known from the chunk of lower jaw shown here, depicted within a silhouetted skull of Uromastyx. The scale bar is in mm. Image: Apesteguía et al. (2016).

At least some studies find mastigures to form a clade with the east Asian butterfly agamas Leiolepis (e.g., Honda et al. 2000, Hugall & Lee 2004, Gauthier et al. 2012), both then being united within Leiolepidinae*. Butterfly agamas are fascinating for all sorts of reasons and I really should write about them at some point as well.

* There’s a long and complex argument over whether Leiolepidinae/Leiolepididae or Uromastycinae/Uromastycidae should win in a priority battle. Modern authors have tended to prefer the former, since it’s 1843 as opposed to 1863 for Theobald’s Uromastycidae. Anderson (1999) argued that the 1843 use of Fitzinger’s name cannot win this battle, since it was originally ‘Leiolepides’ and was not written in its ‘modern’ form by authors pre-1900.

Mastigures and butterfly agamas have not been found to form a clade in all phylogenetic studies: in  Pyron  et al .'s (2013)  study - this cladogram depicts the topology they recovered - the two are successively closer to remaining Agamidae. Note the taxonomic names they used for the agamid lineages.   Like all of these sorts of diagrams, this was produced for my in-prep Vertebrate Fossil Record book, progress on which can be seen here.   Image: Darren Naish.

Mastigures and butterfly agamas have not been found to form a clade in all phylogenetic studies: in Pyron et al.'s (2013) study - this cladogram depicts the topology they recovered - the two are successively closer to remaining Agamidae. Note the taxonomic names they used for the agamid lineages. Like all of these sorts of diagrams, this was produced for my in-prep Vertebrate Fossil Record book, progress on which can be seen here. Image: Darren Naish.

Anyway: here I’ll say what I usually do and remind you that if these animals were mammals or birds they’d almost definitely be considered ‘distinct enough’ to warrant their own ‘family’, a decision that would require Agamidae of tradition to be split into several ‘families’ (I put these taxonomic ranks in quotes because they’re still effectively subjective). In addition to a mastigure family and butterfly agama family, there would be one for Hydrosaurus, one for the Australasian dragons (or amphibolurines), another for the Asian draconines, and so on. A few authors – most notably Scott Moody in his studies of the early 1980s – have at least separated mastigures and butterfly agamas from remaining agamids in a version of Theobald's ‘family’ Uromastycidae.

Butterfly agamas ( Leiolepis ) do look mastigure-like in some features of the face (those tall ridges over the orbits especially), but are otherwise far slimmer, longer-limbed and without their other specialisations. The two groups may be closely related - though it still seems that they diverged during the Late Cretaceous, at least. Image:  TheReptilarium , CC BY 2.0.

Butterfly agamas (Leiolepis) do look mastigure-like in some features of the face (those tall ridges over the orbits especially), but are otherwise far slimmer, longer-limbed and without their other specialisations. The two groups may be closely related - though it still seems that they diverged during the Late Cretaceous, at least. Image: TheReptilarium, CC BY 2.0.

Macey et al. (2000) assumed an Indian origin for mastigures, in which case they’re among several tetrapod groups that followed an ‘Out of India’ dispersal route hypothesised elsewhere for ostriches and certain caecilians and frogs. But this is also contradicted by fossils, since Paleocene members of the lineage – if correctly identified and correctly dated – show that members of the lineage were living in Eurasia before India docked with Eurasia during the Eocene. The best model, therefore, might be one in which mastigures moved into Eurasia at the end of the Cretaceous.

An Eocene map depicting the planet as of around 40 million years ago. At this point, Afro-Arabia had not docked with Eurasia. But members of the mastigure lineage were already present in Eurasia and Afro-Arabia by the time. Image: the original version was used in  Angst et al. (2013) ; this has been modified as per CC BY 2.5.

An Eocene map depicting the planet as of around 40 million years ago. At this point, Afro-Arabia had not docked with Eurasia. But members of the mastigure lineage were already present in Eurasia and Afro-Arabia by the time. Image: the original version was used in Angst et al. (2013); this has been modified as per CC BY 2.5.

Tamar et al. (2018) posited an initial, middle Miocene diversification of the Uromastyx crown-group in south-east Asia followed by Afro-Arabian invasion and diversification. But note that this only applies to crown-group Uromastyx, not to the Saara + Uromastyx clade, nor to the mastigure lineage as a whole, and thus is not inconsistent with an earlier origin and diversification elsewhere.

Tamar  et al . (2018) found  Uromastyx  to consist of two main clades, one mostly associated with the Arabian Peninsula and the borders of the Red Sea, one with the western Sahara.  Saara  forms the sister-group to  Uromastyx . Image: Tamar  et al . (2018).

Tamar et al. (2018) found Uromastyx to consist of two main clades, one mostly associated with the Arabian Peninsula and the borders of the Red Sea, one with the western Sahara. Saara forms the sister-group to Uromastyx. Image: Tamar et al. (2018).

Your regular dose of misanthropy. Finally, all is not well as goes the future of mastigures. As you might guess given my earlier mentions of the pet trade, the sad fact is that uncontrolled, indiscriminate and often illegal collection from the wild is a threat to many populations. Many people involved in the pet reptile trade – those at the sharp end where animals are taken from the wild and smuggled to other countries – have no scruples whatsoever as goes the ethical or managed treatment of animals, and if you don’t believe me look up articles on Anson Wong, the Malaysian wildlife smuggler known as the ‘Lizard King’ (a most inappropriate moniker, given that Kings are supposed to be worthy of respect or admiration).

I would love to see a large, spectacular mastigure in the wild. This mastigure ( U. aegyptia microlepis ), photographed in Al Anbar, Iraq, is a grand, magnificent animal. Image: U.S. Federal Government, Public Domain.

I would love to see a large, spectacular mastigure in the wild. This mastigure (U. aegyptia microlepis), photographed in Al Anbar, Iraq, is a grand, magnificent animal. Image: U.S. Federal Government, Public Domain.

Mastigures have also been much used for food, medicine and as ritual objects (a cleaned mastigure body serves as a traditional baby’s bottle in Morocco, for example), all of which is fine (in theory) when harvesting is kept to sustainable levels… but less fine when exploitation begins to outstrip supply. Those mastigures that have been studied are declining or locally extinct across their range and all species are CITES listed as of 1977. Specifically, they’re on Appendix II of CITES, which refers to species that are not necessarily in immediate danger of extinction but do nonetheless require a control in their trade.

The large size and interesting appearance of many mastigure species - this is a captive  U. aegyptia  - has long made them appealing objects of trade and medicinal use, and as objects for the table too. Image: Darren Naish.

The large size and interesting appearance of many mastigure species - this is a captive U. aegyptia - has long made them appealing objects of trade and medicinal use, and as objects for the table too. Image: Darren Naish.

In some countries where these lizards occur it’s considered a rite of passage for young men to go out and kill as many mastigures as they can, and if you want verification for that you can find photos online where there are great piles of tens or even hundreds of dead mastigures in the backs of trucks. That’s depressing and vile behaviour. Like Anne Frank, I do think that people are essentially good but it’s difficult to maintain a rosy view of humanity when our stated aim seems to be the denuding of wild spaces of their animals.

On that depressing note, we move on.

This article took a lot of work and quickly expanded way beyond the brief ‘here’s a picture of a lizard’ article it was originally intended to be. However, I think that articles like this are useful and would like to keep doing them. Here’s your regular reminder that I require support if this is to continue. I would do more if support allowed. Thanks to those who support me at patreon already.

Iguanian lizards have now been covered quite a few times at Tet Zoo. For previous articles see...

Refs - -

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