Topic
Paracryptodira
About: Paracryptodira is a research topic. Over the lifetime, 16 publications have been published within this topic receiving 697 citations.
Papers
TL;DR: This revised topology has important implications for the evolution of several character complexes, because it implies that the common ancestor of all living turtles must have had a partially braced brain case and a primitive trochlear mechanism.
Abstract: Presented herein is the first morphological analysis of turtle relationships to examine the monophyly of many turtle groups by using only single species as terminals and by integrating a large number of primitive fossil taxa. The data matrix consists of 136 osteological parsimony informative characters with 169 derived character states for 45 fossil and 22 living species of the clade Testudinata. The results corroborate the monophyly of a large number of previously hypothesized clades, but refute the accepted hypothesis regarding the basal split of living turtles. In particular, the primitive turtles Proterochersis robusta, Kayentachelys aprix, Mongolochelys efremovi, Meiolania platyceps, and Kallokibotion bajazidi are removed from their current position as crown turtles and placed along the phylogenetic stem of this clade. The age of the turtle crown is thereby adjusted from the Late Triassic to the Late Jurassic, which is relevant to testing molecular clock hypotheses. This revised topology has...
370 citations
Journal Article•
TL;DR: In this article, the status of Probaena sculpta Hay and its relationship with girders is discussed. And the relationship between girdops and their relationships with other parts of the human body is investigated.
Abstract: . ........... .. ........................ 9 Introduction ....................................... . 95 Systematics ........................................ 97 Forms Inadequately Known but Previously Referred to Glyptops ..... . . . . . . . . . 106 The Status of Probaena sculpta Hay ............................ . 108 Cranial Morphology of Glyptops .............................. . 112 Skull Roof ........................................ 112 Palatal Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Braincase and Otic Region ...... .. .. .. .................. . 115 Lower Jaw ........................................ 124 Relationships of Glyptops .................................. . 126 Literature Cited ........................................ 134
79 citations
TL;DR: According to the results, the stratigraphic appearance of the Pleurosternidae is adjusted from the Kimmeridgian to the Bathonian (Middle Jurassic), which significantly reduces the ghost lineage of Paracryptodira.
Abstract: The Middle Jurassic (Bathonian) turtle material from the Mammal Bed at Kirtlington, Oxfordshire, England, has recently been tentatively referred to the Pleurosternidae, although the known synapomorphies of this clade were absent from the specimens. Here we present new evidence from shell bone histology that corroborates reports of pleurosternids at Kirtlington and further reveal that two different histomorphs (= two different taxa) are present in this locality. The first histomorph presents the distinctive histological structure of pleurosternids, which is described herein for the first time: the external cortical bone layers are differentiated into an inner zone of coarse, irregularly interwoven structural fibre bundles and an outer fine-fibred zone. The second histomorph has a more plesiomorphic structure and can only be assigned to Cryptodira indet. A morphological reassessment of the Kirtlington material fails to recognize two different taxa and shows that only sparse evidence supports the presence of pleurosternids in this locality. Shell bone histology thus appears as a powerful tool to study poorly preserved specimens and may in some case (like with pleurosternids) help resolve phylogenetic relationships. According to our results, the stratigraphic appearance of the Pleurosternidae is adjusted from the Kimmeridgian (Late Jurassic) to the Bathonian (Middle Jurassic), which significantly reduces the ghost lineage of Paracryptodira. Bone histology, turtles, Paracryptodira, Pleurosternidae, Middle Jurassic, Kirtlington.
55 citations
TL;DR: The new phylogenetic proposal, and its analysis in view of stratigraphical distributions, shows that Baenidae was a clade of turtles only known in the Cretaceous and Palaeogene of the North American record but that Pleurosternidae and Compsemydidae were distributed both in North America and Europe.
Abstract: Paracryptodira was an abundant and diverse group of freshwater turtles, recognized both in North America and Europe. Its known record spans the Middle Jurassic to the Eocene. The internal phylogenetic relationships of one of its clades, Baenidae, are relatively well known. However, information on the relationships amongst the non-baenid members is very limited and, so far, poorly justified. A new study on the phylogenetic relationships amongst Paracryptodira is undertaken here through the revision of previously described taxa, the incorporation of information on taxa recently discovered or revised, and the study of new material. In addition, a new taxon from the Late Jurassic of Europe is described: Riodevemys inumbragigas gen. et sp. nov. It is identified as a member of Pleurosternidae, constituting the first generic and specific attribution of a pleurosternid in the Spanish fossil record. Pleurosternidae is obtained here as a robust node whose composition differs from previous proposals. The relationshi...
41 citations
TL;DR: A high diversity of Pancryptodira members in the Lower Cretaceous of Europe, assigned to several nodes is shown, which affects many characters used in the diagnosis of taxa defined by scarce material.
37 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2020 | 2 |
| 2019 | 1 |
| 2017 | 1 |
| 2016 | 1 |
| 2015 | 2 |