See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/284759799 Some peculiarities of the Cretaceous and Palaeogene lizard faunas of the Mongolian People's Republic Article · January 1993 CITATIONS READS 63 317 1 author: Vladimir Alifanov Russian Academy of Sciences 56 PUBLICATIONS 674 CITATIONS SEE PROFILE All content following this page was uploaded by Vladimir Alifanov on 28 January 2016. The user has requested enhancement of the downloaded file. Kaupia • Darmstädter Beiträge zur Naturgeschichte Heft 3 9-13 Darmstadt, 15. März 1993 Vladimir Alifanov Some Peculiarties of the Cretaceous and Palaeogene Lizard Faunas of the Mongolian People's Republic Author's address: Vladimir Alifano, Moscow Paleontological Institute of Academy of Sciences, 123 Profsoyuznaja, Moscow 117 868; Russia. Zusammenfassung In der Kreidezeit existierten in Zentralasien vier heute ausgestorbene und 10 rezente Echsenfamilien. Das bedeutendste Ereignis der Oberkreide ist das Erscheinen der Agamidae, Varanidae, Paravanidae, Teiidae und Anguidae. Gegen Ende der Kreidezeit wurde die Zahl der Familien in der Mongolei auf drei reduziert. Varanidae und Agamidae waren die dominanten Familien im Paläogen. Im mittleren Eozän hatten die Varanidae endgültig die Necrosauridae verdrängt. Zu dieser Zeit erschienen die frühesten Vertreter der Gattung Varanus. Innerhalb der Agamidae des Paläogens gab es Gattungen die Isodontosaurus, Uromastyx oder Leilepis ähnelten. Eine neue Unterfamile der Agamidae - Isodontosaurinae - wird aufgestellt. Nach ihrem oberkretazischen Verschwinden breiteten sich die Iguanidae und Agamidae im Eozän erneut in Zentralasien aus; eine Neueinwanderung der Lacertidae aus Europa fand im unteren Oligozän statt. Abstract Four extinct and ten recent lizard families existed in Central Asia during the Cretaceous. The main feature of the Upper Cretaceous fauna is the appearance of Agamidae, Varanidae, Paravaranidae, Iguanidae, Teiidae and Anguidae. The number of families was reduced to three by the end of the Cretaceous of Mongolia. The Varanidae and Agamidae only were the dominant families in the Palaeogene. The Varanidae forced out Necrosauridae finally by the Middle Eocene. By that time the earliest representatives of Varanus appeared. There are Isodontosaurus-like, Uromastyx-like and Leiolepis-like genera amongst the Palaeogene Agamidae. A new subfamily of Agamidae - Isodontosaurinae is erected. After the Upper Cretaceous extinction the Iguanidae and Anguidae spread in the Eocene of Central Asia again; a new invasion of the Lacertidae from Europe happened in the Lower Oligocene. The material of the fossil lizards from Mongolia Gekkota was collected by the Joint Soviet-Mongolian Pale- Gekkonidae GRAY 1825 ontological Expedition in the South and East of the Hoburogekko ALIFANOV 1989 Gobi Desert during the last 22 years. The numerous Scincomorpha lizard specimens originate from eight Cretaceous Paramacellodidae ESTES 1983 and five Palaeogene localities. ?Xantusidae BAIRD 1859 The bone material was extracted by washing of Acontiidae GRAY 1845 rock and direct collectioning. Slavoia SULIMSKI 1984 The present report is preliminary and represents Anguimorpha the first attempt of the survey of the Mongolian ?Xenosauridae COPE 1886 Lower Cretaceous and Palaeogene lizard faunas. Dorsetisauridae HOFFSTETTER 1967 Dorsetisaurus HOFFSTETTER 1967 The Lower and Upper Cretaceous ?Necrosauridae HOFFSTETTER 1943 The earliest fauna of the Mongolian fossil lizards is Hodzhaculia NESSOV 1985 usually dated as Lower Cretaceous (Aptian-Albian) The presence of the Dorsetisauridae and Para- (KALANDADZE & KURZANOV 1974). This unique fauna macellodidae in the composition of the Hobur's fills in the gap between the faunas of the European fauna drew it together with the Upper Jurassic ones Upper Jurassic and the Upper Cretaceous of Cen- from West Europe (HOFFSTETTER 1967, ESTES 1983) tral Asia and North America. The numerous mac- and North America (PROTHERO & ESTES 1980). This erated material comes from the only locality fact demonstrates the existence of the Lawrasian "Hobur". stage for the lizard faunas of the Northern conti- By the present time the representatives of all nents. lizard infraorder were determined: The Upper Cretaceous localities containing liz- Iguania ard remains are represented by the three Formati- Priscagamidae BORSUK-BIALYNICKA & MOODY 1984 ons Djadochta (Bain-Dzak, Dzamyn-Hond, Tug- (sensu ALIFANOV 1989) rikiyn-Sheere), Barun-Goyot (Khemeen-Tsav, 10 Vladimir Alifanov mx Pf mx mx Pt Fig. 1: Isodontosaurus gracilis GILMOR 1943: specimen MgR/II-39, Upper Cretaceous (Djadochta Formation), Bain- Dzak locality. A: Skull, dorsal view. B: Mandible, labial view. C: Mandible, lingual view. ang - angular, с - coronoid, d - dentary, ept - epipterygoid, fr - frontal, mx - maxilla, pf - prefrontal, pt - ptery- goid, spl - splenial. Hulsan) and Nemegt (Bugeen-Tsav, Guriliyn-Tsav), These families precede the Varanidae and Agamidae which are dated by BARSBOLD 1982 as Santonian- morphologically and ecologically. Lower Campanian (Djadochta and Barun-Goyot The main feature of the Upper Cretaceous fauna Formations) and Upper Campanian-Lower Maas- is the appearance of new lizard families: trichtian (Nemegt Formation). Iguanidae OPPEL 1811 sensu lato By the Upper Cretaceous the Dorsetisauridae Polrussia BORSUK-BIALYNICKA & ALIFANOV 1991 only disappear from the paleontological record of Igua BORSUK-BIALYNICKA & ALIFANOV 1991 Mongolia. Agamidae SPIX 1825 The earlier existing Asiatic families are repre- Isodontosaurus GILMOR 1943 (Fig. 1) sented by the following genera: Teiidae GRAY 1827 Priscagamidae Macrocephalosaurus GILMOR 1943 Priscagama BORUSK-BIALYNICKA 1984 Conicodontosaurus GILMOR 1943 Pleurodontagama BORSUK-BIALYNICKA 1984 Adamisaurus SULIMSKI 1972 Mimeosaurus GILMOR 1943 Erdenetosaurus SULIMSKI 1975 Flaviagama ALIFANOV 1989 Cherminsaurus SULIMSKI 1975 Gekkonidae Darchansaurus SULIMSKI 1975 Gobekko BORSUK-BIALYNICKA 1990 Mongolochamops ALIFANOV 1988 Paramacellodidae Piramicephalosaurus ALIFANOV 1988 a few undescribed genera Lacertidae GRAY 1825 Xantusiidae Anguidae GRAY 1825 Eoxanta BORSUK-BIALYNICKA 1988 Bainguis BORSUK-BIALYNICKA 1984 (sensu BORSUK- Acontiidae BIALYNICKA 1991) Slavoia SULIMSKI 1984 Varanidae GRAY 1827 Xenosauridae Telmasaurus GILMOR 1943 Carussia BORSUK-BIALYNICKA 1987 Saniwides BORSUK-BIALYNICKA 1984 Shinisauroid.es BORSUK-BIALYNICKA 1985 Cherminotus BORSUK-BIALYNICKA 1984 (Fig. 2) Globaura BORSUK-BIALYNICKA 1988 Saniwa sp. (Fig. 3) Necrosauridae Paravaranidae Proplatinotia BORSUK-BIALYNICKA 1984 Paravaranus BORSUK-BIALYNICKA 1984 Parviderma BORSUK-BIALYNICKA 1984 These new families might be subdivided into Gobiderma BORSUK-BIALYNICKA 1984 three groups. Taking into consideration the undescribed gen- The first group is made up from Varanidae and era, the Necrosauridae and Priscagamidae are the Agamidae, which are Asian by origin and had a most diverse among the above mentioned families. powerful generic diversity in Asia only. Some Peculiarties of the Cretaceous and Palaegene Lizard Faunas of the Mongolian People's Republic 11 pmx and Amphisbaenia are known from the Upper Paleocene, but one could assume their distribution mx in the Upper Cretaceous. More likely, the named groups came to Asia from North America. If right, Hobur's fauna was formed before the connection of Asia to North America. The distribution of the second group both in Asia and South America might probably occur only due to its North American origin as well as the earlier interamerican connection, than that of North America to Asia. This might explain the absence of the Asian Necrosauridae, Varanidae, Xenosauri- dae and Agamidae in the South America. The third group includes the Paravaranidae and Lacertidae. To my opinion, the problematic mono- typical Paravaranidae display a lot of similiarities with the mosasauroid Aigialosauridae known from the Upper Jurassic-Lower Cretaceous of Europe. If true, Paravaranidae might be regarded as Jurassic relic in Mongolian Upper Cretaceous. Lacertidae, which might have a hidden Mesozoic distribution in Lawrasian time, are a more problematic family. 5 mm In the terminal Cretaceous Nemegt Formation Fig. 2: Cherminotus longifrons BORSUK-BIALYNICKA the quantity of the lizard families was reduced to 3 1984; specimen PIN 3142/323; Upper Cretaceous (Varanidae, Necrosauridae, Teiidae). The absence (Barun-Goyot Formation ), Khermeen-Tsav locality, of Agamidae in Nemegt deposits and Varanidae in ept - epiterygoid, fr - frontal, j - jugal, 1 - lateral, the Upper Paleocene ones indicates to some local mx - maxilla, n - nasal, p - parietal, pfr - prefrontal, features of the lizard extinction. pmx - premaxilla, po - postorbiatal, pofr - postfron- tal, pt - pterygoid. The Upper Paleocene (Table 1) The impoverishment of the lizard fauna kept on The second group includes modern Iguanidae going in the Cenozoic. By the Upper Paleocene the sensu lato, Teiidae and Anguidae as well as Ophidia Necrosauridae (Necrosaurus sp.) and Agamidae only and Amphisbaenia. All these Squamata are united are recorded. The latter are represented by the by modern distribution in South America. The undescribed Leiolepis-like and Isodontosaurus-like earliest fossil Teiidae, Anguidae and Ophidia are genera. known from the Upper Cretaceous of North Isodontosaurus-like forms have got no fang-like America. The earliest North American Iguanidae teth and pronounced hatchling teeth. The tooth Fig. 3: Saniwa sp., specimen PIN 3142/322