New dinosaur species from the Upper Triassic Upper Maleri and Lower Dharmaram formations of Central India

Abstract

The beginning of dinosaur evolution is currently known based on a handful of highly informative Gondwanan outcrops of Ischigualastian age (late Carnian-early Norian). The richest Triassic dinosaur records of the southern continents are those of South America and South Africa, with taxonomically diverse faunas, whereas faunas from India and central Africa are more poorly known. Here, the known diversity of Gondwanan Triassic dinosaurs is increased with new specimens from central India, which allow a more comprehensive characterisation of these dinosaur assemblages. Five dinosauriform specimens are reported from the probable late Norian-earliest Rhaetian Upper Maleri Formation, including two new sauropodomorph species, the nonplateosaurian Nambalia roychowdhurii and the plateosaurian Jaklapallisaurus asymmetrica, a guaibasaurid and two basal dinosauriforms. The Lower Dharmaram Formation, probably latest Norian-Rhaetian in age, includes basal sauropodomorph and neotheropod remains, providing the second record of a Triassic Gondwanan neotheropod. The currently available evidence suggests that the oldest known Gondwanan dinosaur assemblages (Ischigualastian) were not homogeneous, but more diverse in South America than in India. In addition, the Upper Maleri and Lower Dharmaram dinosaur assemblages resemble purported coeval South American and European beds in the presence of basal sauropodomorphs. Accordingly, the current available evidence of the Triassic beds of the Pranhita-Godavari Basin suggests that dinosaurs increased in diversity and abundance during the late Norian to Rhaetian in this region of Gondwana.

A second species ofEucnemesaurusVan Hoepen, 1920 (Dinosauria, Sauropodomorpha): new information on the diversity and evolution of the sauropodomorph fauna of South Africa's lower Elliot Formation (latest Triassic)

“…Although only weakly supported by two synapomorphies (laterally expanded tables at the midlength of the dorsal surface of the neural spines in both cervical and pectoral vertebrae [char. 149.2; known only for Ruehlia and convergently acquired in Massospondylidae]; posteriorly projecting heel on the distal end of the iliac ischial peduncle [253.1; present also in Riojasaurus and some massospondylids]), this result nonetheless suggests an expanded, global distribution of plateosaurids that also encompasses southern Africa-a result geographically congruent with the phylogenetic hypotheses of Novas et al (2011) (although see below for a discussion on problems pertaining to Plateosauravus).…”

“…Although the Massospondylidae achieved a cosmopolitan distribution during the Early Jurassic-with forms known from China (Lufengosaurus; Barrett et al, 2005), Antarctica (Glacialisaurus; Smith and Pol, 2007), Argentina (Adeopapposaurus and Leyesaurus;Mart ınez, 2009;Apaldetti et al, 2011), South Africa (Massospondylus; Kitching and Raath, 1984), and possibly India (Pradhania; Novas et al, 2011) and North America (Sarahsaurus cf. Row et al, 2010)-only Coloradisaurus brevis hails from rocks confidently datable to the Late Triassic.…”

The Late Triassic dinosauromorph Sacisaurus agudoensis (Caturrita Formation; Rio Grande do Sul, Brazil): anatomy and affinities

“…The unresolved (sauropodomorph, herrerasaur) or unpredicted (ornithischian) phylogenetic organization within dinosaur subgroups is not the focus of this reanalysis and will not be discussed further. They may result from restricted character sampling, and the topology could easily be more structured with the inclusion of additional characters (Langer & Benton 2006;Butler et al 2008;Novas et al 2011) that change along those branches.…”

Redescription of a Nearly Complete Skull ofPlateosaurus(Dinosauria: Sauropodomorpha) from the Late Triassic of Trossingen (Germany)

“…According to a few authors, the basal sauropodomorphs are monophyletic, the Prosauropoda, that is phylogenetically positioned as the sister clade to sauropods (Cruickshank, 1975;Sereno, 1989;Galton, 1990;Gauffre, 1995;Wilson and Sereno, 1998;Galton and Upchurch, 2004;Barrett et al, 2005;Martínez, 2009). However, most studies have questioned prosauropod monophyly and most currently agree that these animals form a paraphyletic assemblage of successive outgroup taxa to Sauropoda (Romer, 1956;Colbert, 1964;Charig et al, 1965;Bonaparte, 1969;Yates, 2003a;Yates and Kitching, 2003;Upchurch et al, 2007;Martínez and Alcober, 2009;Yates et al, 2010;Novas et al, 2011;Pol et al, 2011). Basal sauropodomorphs (although not monophyletic) are among the earliest and more primitive dinosaurs, with a fossil record that spans the Carnian (Early Late Triassic) through the Early Jurassic (Galton and Upchurch, 2004).…”