First occurrence of brachyopid temnospondyls in Southeast Asia and review of the Mesozoic amphibians from Thailand

Thanit Nonsrirach,Sita Manitkoon,Komsorn Lauprasert

doi:10.5194/fr-24-33-2021

Abstract

Abstract. The non-marine Mesozoic sedimentary rocks of Thailand, which consist of the Indochina block and the Sibumasu block, have yielded several terrestrial and aquatic vertebrate fossils, but only few amphibian remains have been reported. Here, we present an overview on the Thai amphibian palaeo-diversity based on the literature, re-examination of published material, new findings, and unpublished material. Thai amphibian fossil remains are assigned to Stereospondyli (Cyclotosauridae, Plagiosauridae, and Brachyopoidea) and Anura and were discovered from four formations, ranging from the Upper Triassic to Lower Cretaceous of Thailand. The occurrence of Brachyopidae in Thailand, which are related to Chinese forms, supports the previous hypothesis of physical connections between the Indochina blocks and the Sibumasu block during the Mesozoic era.

Highlights

The amphibians of the Paleozoic and the Mesozoic can be dived into three major clades: the Seymouriamorpha, the Lepospondyli, and the Temnospondyli (Vitt and Caldwell, 2014)
Basal members of temnospondyls were the most diverse and most successful group of amphibians in the Paleozoic, which lived during the Mesozoic Era (Damiani and Rubidge, 2003; Schoch, 2014)
In order to understand the diversity and biogeography of Thai Mesozoic amphibians, we describe and re-check the taxonomic status of all amphibian remains housed in the collections of the Sirindhorn Museum (SDM, Kalasin Province) and the Palaeontological Research and Education Centre of Mahasarakham University (PRC, Mahasarakham Province)

Summary

Introduction

The amphibians of the Paleozoic and the Mesozoic can be dived into three major clades: the Seymouriamorpha, the Lepospondyli, and the Temnospondyli (Vitt and Caldwell, 2014). The Phu Kradung Formation consists of sequences of sandstone, siltstone, and mudstone deposited on a lacustrine-dominated alluvial floodplain environment (Meesook, 2000; Racey, 2009) This formation is assigned to Upper Jurassic based on palynomorphs, bivalves (Racey et al, 1994, 1996; Meesook, 2000), and vertebrate remains which consist of hybodont sharks (Cuny et al, 2005), actinopterygians (Cavin et al, 2003; Cavin and Suteethorn, 2006), temnospondyls (Buffetaut, et al, 1994a), turtles (Tong et al, 2009), crocodiles (Buffetaut and Ingavat, 1980), and dinosaurs (Buffetaut, et al, 2014).

Materials

Unpublished material

Discussion

Conclusions