Original Articles

First record of Mesozoic terrestrial vertebrates from Lithuania: phytosaurs (Diapsida: Archosauriformes) of probable Late Triassic age, with a review of phytosaur biogeography

STEPHEN L. BRUSATTE^a1a2 c1, RICHARD J. BUTLER^a3, GRZEGORZ NIEDŹWIEDZKI^a4a5, TOMASZ SULEJ^a6, ROBERT BRONOWICZ^a7 and JONAS SATKŪNAS^a8a9

^a1 Division of Paleontology, American Museum of Natural History, Central Park West at 79^th Street, New York, NY 10024, USA

^a2 Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA

^a3 GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Straße 10, D-80333 Munich, Germany

^a4 Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden

^a5 Faculty of Biology, University of Warsaw, Banacha 2, 02-079 Warsaw, Poland

^a6 Institute of Paleobiology PAN, Twarda 51/55, 00-818 Warsaw, Poland

^a7 Faculty of Geology, University of Warsaw, Al. Żwirki i Wigury 93, 02-089 Warsaw, Poland

^a8 Geological Survey of Lithuania, 35 Konarskio Street 2600 Vilnius, Lithuania

^a9 Vilnius University, Ciurlionio Street 21, Vilnius, Lithuania

Abstract

Fossils of Mesozoic terrestrial vertebrates from Lithuania and the wider East Baltic region of Europe have previously been unknown. We here report the first Mesozoic terrestrial vertebrate fossils from Lithuania: two premaxillary specimens and three teeth that belong to Phytosauria, a common clade of semiaquatic Triassic archosauriforms. These specimens represent an uncrested phytosaur, similar to several species within the genera Paleorhinus, Parasuchus, Rutiodon and Nicrosaurus. Because phytosaurs are currently only known from the Upper Triassic, their discovery in northwestern Lithuania (the Šaltiškiai clay-pit) suggests that at least part of the Triassic succession in this region is Late Triassic in age, and is not solely Early Triassic as has been previously considered. The new specimens are among the most northerly occurrences of phytosaurs in the Late Triassic, as Lithuania was approximately 7–10° further north than classic phytosaur-bearing localities in nearby Germany and Poland, and as much as 40° further north than the best-sampled phytosaur localities in North America. The far northerly occurrence of the Lithuanian fossils prompts a review of phytosaur biogeography and distribution, which suggests that these predators were widely distributed in the Triassic monsoonal belt but rarer in more arid regions.

(Received January 15 2012)

(Accepted May 23 2012)

(Online publication July 18 2012)

Keywords:

• palaeobiogeography;
• Lithuania;
• phytosaurs;
• stratigraphy;
• Triassic;
• vertebrate palaeontology

Correspondence:

^c1 Author for correspondence: sbrusatte@amnh.org