The First Articulated Trematosaur ‘amphibian’ from the Lower Triassic of Madagascar: Implications for the Phylogeny of the Group

Abstract

ABSTRACT. The temnospondyl Wantzosaurus elongatus Lehman, 1961, from the Lower Triassic of Madagascar, is redescribed on the basis of a new specimen, which is the most complete trematosaur ever found. Detailed osteological observations and comparisons provide new data on the anatomy, ontogeny, palaeobiology and palaeoecology of this peculiar marine`amphibian'. The morphology of this aquatically readapted taxon is compared to that of marinè reptiles': Wantzosaurus might have been able to swim by undulation. A phylogenetic analysis of the trematosaurs is performed for the ®rst time and suggests that Wantzosaurus is a derived taxon within the clade Trematosauridae. The family is de®ned on the basis of derived character states and is shown to be monophyletic.

Preliminary observations on the bone microstructure, growth patterns, and life habits of some Triassic temnospondyls from India

“…It may be hypothesized that in the semi-arid Triassic environment with high seasonal rainfall, the temnospondyls examined were dependent on shallow pools or lakes and rivers, as well as retaining a high level of terrestriality to enable movement from one habitat to another, as suggested by Pawley and Warren (2005) for Lydekkerina huxleyi. This finding, based on bone microstructure, contrasts with the skeletal designs of the trematosaurids and paracyclotosaurids (Schoch and Milner, 2000;Steyer, 2002). However, Laurin et al (2004) in a recent study on Paleozoic temnospondyls have shown that these animals were terrestrial, and were secondarily adapted to water.…”

A supertree of early tetrapods

“…We also excluded trees superseded by studies that incorporate a broader taxon and character sample (e.g. stereospondyl analyses predating Schoch (2000); Yates & Warren (2000); Damiani (2001) and Steyer (2002) …”

A trematosauroid temnospondyl from the Middle Triassic of Jordan

“…The position of Inflectosaurus is equivocal, despite close resemblance of the mandible of that taxon to the Jordan find. The different variants, reflected by the alternative trees, include versions in which Microposaurus, the Jordan taxon, and Inflectosaurus form a clade (adopted here for the preferred phylogeny presented in Figure 5B), as well as other groupings in which either is more closely related to the Metoposauridae and Callistomordax; Steyer (2002) arrived at a similar result. At any rate, cladistic analysis supports the attribution of SMNS 81772 to the Trematosauroidea sensu Damiani & Yates (2003) and indicates a close relationship with the South African genus Microposaurus (Fig.…”

“…The present phylogenetic analysis is based on character lists and data sets that developed during the last three decades, starting with Warren & Black (1985), Milner (1990), Yates & Warren (2000), Damiani (2001), Steyer (2002), Damiani & Yates (2003), and Schoch (2006Schoch ( , 2008. Character-codings are based on the data matrix of Schoch (2008), to which three new taxa were added (Inflectosaurus amplus, Microposaurus casei Haughton, 1925, and the Jordan specimen).…”