[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

NEW GOBI LIZARDS



Recently received the following...

GAO KEQIN and NORELL, M. A. 2000. Taxonomic composition and 
systematics of Late Cretaceous lizard assemblages from Ukhaa Tolgod 
and adjacent localities, Mongolian Gobi Desert. _Bulletin of the 
American Museum of Natural History_ 249, 1-118.

Many new taxa, much new material. A lot on the localities and their 
lithologies, fauna and correlations. As for the lizards, here is a quick 
rundown - some really fascinating taxa here.

_Ctenomastax parva_ is a new non-acrodont iguanian with slender 
teeth arranged in a comb-like fashion (hence the name). It has a number 
of similarities with crotaphytines and is clearly different in teeth and 
skull shape from _Igua_ and _Polrussia_, the two nonacrodont 
iguanians from Khulsan.

_Temujinia ellisoni_ is another new iguanian, and probably not a 
member of Acrodonta ('agamids' + chamaeleons). It has low-crowned 
'swollen' tricuspid teeth and is thus obviously distinct from the above 
three and _Anchaurosaurus_ Gao and Hou. Gao and Norell point out 
the forked postfrontal that clasps the frontal-parietal suture in 
_Temujinia_, a character previously used to support monophyly of 
scleroglossans/scincogekkonomorphs. The species name honours Mark 
Ellison, the AMNH artist, and the genus is from the Mongolian name 
for Genghis Khan (Temujin). Some irony here then: one of the Gobi's 
smallest predators has a name based on the same derivation as (one of 
the names of) the Gobi's largest predator....

_Zapsosaurus sceliphros_: also new, an iguanian probably close to 
_Anchaurosaurus gilmorei_. _Anchaurosaurus_ was regarded as a 
crotaphytine (aka crotaphytid) by Alifanov but Gao and Norell regard 
this as non-supportable. Very gracile skull.

New material and a new diagnosis of _Polrussia mongoliensis_ are 
presented - presence of a shared parietal character leads them to 
suggest an affinity with _Igua minuta_. Also new material and 
discussion of the acrodontans _Mimeosaurus_, _Priscagama_, little 
spiky _Phrynosomimus_ and the indeterminate iguanian 
_Isodontosaurus gracilis_ (possible affinities with _Uromastyx_ are 
noted). _Phrynosomimus_ was named by Alifanov 1996 - I wonder if 
this is the only reptile outside of Theropoda to have a 'mimus' name? It 
mimics _Phrynosoma_: another dinosaur link - one of 
_Phrynosoma_'s junior synonyms is _Centrosaurus_. 

_Myrmecodaptria microphagosa_, 'little eating anteater', is an unusual 
gekkotan with an elongate skull (for a gekkotan) and a reduced number 
of small peglike, widely spaced teeth (like all gekkotans it lacks 
pterygoid teeth). I think these characters explain the name they give it, 
though possible ant-eating habits aren't discussed in the text (though 
they are mentioned in the discussion at the end). Nick L will be 
pleased:)

Moving onto scincomorphs, there's spectacuar further material of the 
polyglyphanodontines _Adamisaurus_, _Gobinatus_, 
_Tchingisaurus_, _Pyramicephalosaurus_, _Macrocephalosaurus_, 
Erdenetesaurus_, and _Cherminsaurus_. The photos of the skulls and 
close-up shots of the teeth here are amazing. Many of these taxa were 
only recently named and described by Alifanov, so they aren't as well 
known to workers as they perhaps should be.

_Parmeosaurus scutatus_ is a new possible scincoid. It's certainly 
covered in osteoderms (both head and body) but has a unique narrow, 
elongate skull. The osteoderms are most like those of cordylids and 
paramacellodids (I recall from a SVP presentation that monophyly of 
the latter is in doubt).

_Hymenosaurus clarki_ is another possible scincoid. Jim Clark has 
clearly recently gotten married as this animal is named after Hymen, 
the god of marriage [ah, that explains it...], and Clark himself. How 
sweet. The nostrils are retracted some and there's no suggestion of a 
secondary palate (as in other scincoids).

Among other scincomorphs, new specimens and discussions of 
_Slavoia_, _Globaura_ and _Eoxanta_. _Slavoia_ is a peculiar wide-
skulled, long-bodied form that superficially recalls burrowing teiids or 
reduced-limbed skinks. In fact _Slavoia_ has been referrred to both 
groups by Sulimski, being most recently regarded as an acontiine skink. 
Gao and Norell note that this can't be supported at the present time.

Moving, finally, to anguimorphs, there's new stuff here on _Carusia_, 
_Gobiderma_, _Estesia_ and _Cherminotus_. There is a drop-dead 
gorgeous incredible photo of an _Estesia_ skull. _Aiolosaurus oriens_ 
is a new small varanoid that, perhaps like _Cherminotus_, may be a 
basal member of this group. 

The work ends with discussion of the stratigraphic distributions of the 
lizard fossils, their palaeoecology and modes of preservation. Maybe 
_Phrynosomimus_ was an eat-eater like _Phrynosoma_, sharp-skulled 
_Parmeosaurus_ was a burrow-dweller and _Slavoia_ was a 
burrowing worm predator, they suggest. Herbivorous lizards are rare at 
Uhkaa Tolgod, perhaps unlike some other Gobi localities. This text is 
an absolute must if you're a fan of dead lizards or if you're interested in 
the palaeoecology or faunal correlation of the Gobi faunas. The many 
photos are incredible and Gao and Norell have no doubt paved the way 
for many future phylogenetic studies on the taxa they describe.

Back to the proofs....

DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth & Environmental Sciences
UNIVERSITY OF PORTSMOUTH
Burnaby Building
Burnaby Road                           email: darren.naish@port.ac.uk
Portsmouth UK                          tel (mobile): 0776 1372651     
P01 3QL                                tel (office): 023 92842244