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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
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....
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