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

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on the Thai amphibian palaeo-diversity based on the literature, re-examination of published material, new findings, and unpublished material.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.

First discovery of parasite eggs in a vertebrate coprolite of the Late Triassic in Thailand

“…The cylindrical and curved shape of the coprolite and the absence of prey remains are typical of the Crurotarsi, especially crocodile-like animals [ 3 , 20 , 51 , 52 ]. Crocodiles are not known in Huai Hin Lat but abundant vertebrate assemblages have been discovered in several outcrops of the Huai Hin Lat Formation including actinopterygian fishes [ 25 , 34 , 35 ], lungfish [ 36 , 37 ], temnospondyls [ 25 , 27 , 38 , 39 ], turtles [ 40 , 41 ], and phytosaurs [ 42 ]. The studied coprolite was therefore likely produced by a crocodile-like reptile, possibly a phytosaur, a reptile that evolved convergently with crocodilians, and whose tooth and bone remains have been found in the same formation [ 25 , 42 , 43 ].…”

“…[ 25 , 33 ], ginglymodians [ 25 , 34 , 35 ], lungfishes (possibly Ferganoceratodus sp.) [ 36 , 37 ], temnospondyls (including Cyclotosaurus and Plagiosauridae) [ 25 , 27 , 38 , 39 ], the primitive stem-turtle Proganochelys ruchae [ 40 , 41 ], and phytosaurs [ 42 ]. Furthermore, archosauromorph footprints were identified as cf.…”

“…The coprolite was The Huai Nam Aun outcrop contains various beds of limestone and mudstone, deposited in brackish water or freshwater and in a low energy depositional environment [25]. The vertebrate fossil remains in the outcrop consist of Hybodus teeth, ganoid fish scales, and temnospondyl fragments [25][26][27]. The Huai Nam Aun outcrop is part of the Huai Hin Lat Formation (Fig 1 ), which has been dated as Carnian-Norian based on palynomorphs, plant macroremains, conchostracans, and vertebrate remains [28][29][30][31][32].…”

Ornithischian dinosaurs in Southeast Asia: a review with palaeobiogeographic implications

“…Interestingly, the vertebrate faunas from the lower Phu Kradung Formation share similarities with the those from the Middle-Late Jurassic (Bathonian-Callovian) Khlong Min Formation of the Thai southern peninsula from the Sibumasu Terrane (Buffetaut et al 2005a;Cuny et al 2014). Hybodont sharks (Cuny et al 2014), brachyopoid temnospondyls (Buffetaut et al 1994;Nonsrirach et al 2021), teleosaurid crocodylomorphs (Buffetaut et al 1994;Cuny et al 2009;Martin et al 2019), and mamenchisaurid sauropods (Buffetaut et al 2005a;Suteethorn et al 2013) from both the lower Phu Kradung and Khlong Min Formations indicate a wide distribution.…”

A New Basal Neornithischian Dinosaur from the Phu Kradung Formation (Upper Jurassic) of Northeastern Thailand

“…Several new taxa have been named from Phu Noi, including the freshwater hybodont shark Acrodus kalasinensis [24], the ginglymodian actinopterygian Isanichthys lertboosi [28], the lungfish Ferganoceratodus annekempae [29], the xinjiangchelyid turtles Phunoichelys thirakupti and Kalasinemys prasarttongosothi [30,31], and the teleosaurid crocodylomorphs Indosinosuchus potamosiamensis and Indosinosuchus kalasinensis [25,32]. This site has also produced brachyopid temnospondyls, pterosaurs, and numerous dinosaur elements belonging to mamenchisaurid sauropods, metriacanthosaurid (=sinraptorid) theropods, and small basal neornithischians [20,21,[33][34][35][36][37] that are currently under study. The Phu Noi site is close to the Late Jurassic Phu Kradung Formation outcrop of Ban Khok Sanam village (about 3 km away from Phu Noi) where a dorsal vertebra of a stegosaur was reported [20,38].…”