Topic
Diphydontosaurus
About: Diphydontosaurus is a research topic. Over the lifetime, 11 publications have been published within this topic receiving 336 citations.
Papers
TL;DR: A study of 49 synapomorphs in the Diapsida suggests that the lack of a quadrate-quadratojugal conch and the complete lower temporal bar are secondarily derived in the `living fossil' Sphenodon punctatus, and the tuatara is therefore much less archaic than hitherto proposed.
Abstract: The skull and lower jaw of a new sphenodontid reptile Diphydontosaurus avonis is described from disarticulated bones. The fossils were recovered from a detrital limestone of Rhaetian age deposited within solutional and tectonically formed fissures within the Carboniferous Limestone of Tytherington quarry near Bristol. The bone remains, numbering over 1000, are exquisitely preserved with intact facets. Diphydontosaurus was the smallest member of an insular fauna, was primarily insectivorous, and probably formed locally high-density populations. Uniquely for a sphenodontid, Diphydontosaurus had pleurodont teeth on the premaxilla and on the anterior regions of the dentary and maxilla. However, Diphydontosaurus also has the series of acrodont teeth alternating in size on the maxilla and dentary which is characteristic of the Sphenodontidae and particularly Sphenodon. An analysis of 49 synapomorphs in the Diapsida emphasises the sphenodontid nature of Diphydontosaurus. A study of these synapomorphs among the other Triassic sphenodontids Clevosaurus and Planocephalosaurus and the eosuchian Gephyrosaurus suggests that the lack of a quadrate-quadratojugal conch and the complete lower temporal bar are secondarily derived in the `living fossil' Sphenodon punctatus. The tuatara is therefore much less archaic than hitherto proposed. Functional reasons are advocated for the loss of the conch and the regrowth of a complete lower temporal bar. Transformation series are described which could have led to the shape of the maxilla, dentary, premaxilla, palatine and to the loss of the lacrimal in Sphenodon.
161 citations
TL;DR: New sphenodontian material from the Jurassic Kota Formation of peninsular India indicates the presence of a primitive pleurodont lepidosauromorph similar to the basal rhynchocephaliansGephyrosaurus and Diphydontosaurus from Britain.
78 citations
1 Jul 2014
TL;DR: In this article, microvertebrates from the original Durdham Down fissure rocks were used to expand the taxonomic diversity of the island fauna, revealing that it was dominated by the sphenodontian Diphydontosaurus, and that archosauromorphs including sphenosuchian crocodylomorphs, coelophysoid theropods, and the basal sauropodomorph Thecodontosaurus, were diverse.
Abstract: Since the discovery of the basal sauropodomorph dinosaur Thecodontosaurus in the 1830s, the associated fauna from the Triassic fissures at Durdham Down (Bristol, UK) has not been investigated, largely because the quarries are built over. Other fissure sites around the Bristol Channel show that dinosaurs represented a minor part of the fauna of the Late Triassic archipelago. Here we present data on microvertebrates from the original Durdham Down fissure rocks, which considerably expand the taxonomic diversity of the island fauna, revealing that it was dominated by the sphenodontian Diphydontosaurus , and that archosauromorphs, including sphenosuchian crocodylomorphs, coelophysoid theropods, and the basal sauropodomorph Thecodontosaurus , were diverse. Importantly, a few fish teeth provide new information about the debated age of the fissure deposit, which is identified as lower Rhaetian. Thecodontosaurus had been assigned an age range over 20–25 Myr of the Late Triassic, so this narrower age determination (209.5–204 Myr) is important for studies of early dinosaurian evolution.
28 citations
1 Jun 2015
TL;DR: The Woodleaze fissure fauna is nearly monofaunal, comprising >98% of a new Clevosaurus species, as well as some Diphydontosaurus fragments, a possible undescribed lepidosaur and a few fish fossils.
Abstract: During the Late Triassic and Early Jurassic, diverse terrestrial vertebrates were preserved in fissures formed in Carboniferous Limestone on an island archipelago spanning from the south of Wales to the north and south of Bristol Here we report the faunas of two new fissures in Woodleaze quarry, near to Tytherington quarry, where the vertebrate fauna is already well known The new site extends the lateral distribution of fissures in this vicinity to over 900 m, and fissures sampled along that transect show a southerly change in the dominant species and a reduction in diversity The Woodleaze fissure fauna is nearly monofaunal, comprising >98% of a new Clevosaurus species, as well as some Diphydontosaurus fragments, a possible undescribed lepidosaur and a few fish fossils The new clevosaur is distinguished from the type species Clevosaurus hudsoni by its dentition, and by being smaller (average long bones are 40–80% the length of C hudsoni ) In addition, the collection also includes individual skeletal elements that were not previously well described, thus expanding our knowledge of clevosaur anatomy The Woodleaze bones are preserved as black or dark grey, rather than white, and this preservation mode and single-species dominance occurs elsewhere only in the Windsor Hill fissure where Oligokyphus predominates Together with Tytherington, this location offers an exceptional opportunity to study a Triassic terrestrial biota across an extended distance, and to compare near-littoral niches with more inland island habitats
26 citations
TL;DR: New sphenodontian material from the Jurassic Kota Formation of peninsular India indicates the presence of a primitive pleurodont lepidosauromorph similar to the basal rhynchocephaliansGephyrosaurus and Diphydontosaurus from Britain.
24 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2019 | 1 |
| 2017 | 1 |
| 2015 | 1 |
| 2014 | 1 |
| 2012 | 2 |