First arboreal 'pelycosaurs' (Synapsida: Varanopidae) from the early Permian Chemnitz Fossil Lagerstätte, SE Germany, with a review of varanopid phylogeny

Spindler, Frederik; Werneburg, Ralf; Schneider, Joerg W.; Luthardt, Ludwig; Annacker, Volker; Rößler, Ronny

doi:10.1007/s12542-018-0405-9

Cited by 53 publications

(72 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…), although circumorbital ornamentation is absent in the basal varanopid Ascendonanus nestleri (Spindler et al . ). Altogether, it is clear that the hypothesized highly distinct phylogenetic positions of varanopids (as synapsids) and early diapsids (as sauropsids) are supported by only a small number of character states.…”

Section: Discussionmentioning

confidence: 97%

“…In non‐varanodontine varanopids similarities also include slender limbs, relatively small body size and recurved conical teeth, as in the basal varanopids Archaeovenator and Ascendonanus (Reisz & Dilkes ; Spindler et al . ). Within the current paradigm (Reisz & Modesto ; Reisz et al .…”

Section: Discussionmentioning

confidence: 97%

“…This morphology is retained in most early sauropsids, as seen in all non‐diapsid eureptiles, including captorhinids (Fox & Bowman ; Carroll ; Heaton ) and in many early synapsids (Romer & Price ; Langston & Reisz ; Reisz & Dilkes ; Spindler et al . ). The lacrimal of araeoscelidian diapsids makes an extensive contact with the external naris, and this is facilitated by the presence of a dorsoventrally low maxilla (Reisz ; Reisz et al .…”

Section: Descriptionmentioning

confidence: 97%

“…A ‘massive’ neural arch is present in the varanopid Archaeovenator (Reisz & Dilkes ); a low axial neural spine is present in Ascendonanus and other small varanopids (Spindler et al . ).…”

Section: Descriptionmentioning

confidence: 97%

“…; Spindler et al . ) although even within these groups the character state remains variable, as in the varanopid Archaeovenator where the parasphenoid is edentulous (Reisz & Dilkes ). Dentition is entirely absent in ophiacodontids, edaphosaurids and sphenacodontids where the parabasisphenoid is preserved (Benson ).…”

Section: Descriptionmentioning

confidence: 99%

See 4 more Smart Citations

A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny

Ford

Benson

2018

Papers in Palaeontology

View full text Add to dashboard Cite

The earliest known neodiapsid Orovenator mayorum from the lower Permian of Oklahoma is redescribed using high‐resolution μCT, revealing remarkable details of the skull anatomy. Our findings are relevant to both palaeoecology (suggesting burrowing and nocturnality) and phylogeny. Orovenator and other sauropsids share at least 16 character states with varanopids, many of which were not recognized by previous studies. These include a rounded subnarial shelf of the premaxilla, a posterodorsal extension of the external naris, the asymmetrical bifurcation of the anterior vomer, and a prominent dorsomedial shelf of the surangular. This exceptional degree of similarity between Orovenator and varanopids (a nominally synapsid clade) questions our current understanding of relationships among early amniotes. We test this by including Orovenator in a phylogenetic data matrix used in an earlier study to differentiate between early diapsids and synapsids, and find a monophyletic clade of Orovenator + varanopids within Diapsida. Recent phylogenetic research on early amniote evolution has focused on resolving intra‐clade affiliations rather than the interrelationships of major taxonomic groups. Nevertheless, the relative incompleteness of existing phylogenetic character lists for early amniotes can only be remedied by detailed cross‐clade assessment. We therefore suggest that early amniote relationships require further scrutiny before we can confidently accept or reject our new phylogenetic hypothesis.

show abstract

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 97%

Section: Descriptionmentioning

confidence: 97%

Section: Descriptionmentioning

confidence: 97%

Section: Descriptionmentioning

confidence: 99%

See 3 more Smart Citations

A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny

Ford

Benson

2018

Papers in Palaeontology

View full text Add to dashboard Cite

show abstract

Endocasts of the basal sauropsid Captorhinus reveal unexpected neurological diversity in early reptiles

Bazzana

Evans

Bevitt

et al. 2022

The Anatomical Record

View full text Add to dashboard Cite

Captorhinids are a group of Paleozoic amniotes that represents one of the earliest‐diverging clades of eureptiles. Although captorhinids are one of the best‐known and most well‐studied clades of early amniotes, their palaeoneuroanatomy has gone largely unexamined. We utilized neutron computed tomography to study the virtual cranial and otic endocasts of two captorhinid specimens. The neurosensory anatomy of captorhinids shows a mixture of traits considered plesiomorphic for sauropsids (no expansions of the cerebrum or olfactory bulbs, low degree of encephalization, low ossification of the otic capsule) and those considered more derived, including moderate cephalic and pontine flexures and a dorsoventrally tall bony labyrinth. The inner ear clearly preserves the elliptical, sub‐orthogonal canals and the short, rounded vestibule, along with an unusually enlarged lateral canal and a unique curvature of the posterior canal. The reconstructed neurosensory anatomy indicates that captorhinids were sensitive to slightly higher frequencies than many of their contemporaries, likely reflecting differences in body size across taxa, while the morphology of the maxillary canal suggests a simple, tubular condition as the plesiomorphic state for Sauropsida and contributes to the ongoing discussions regarding the phylogenetic placement of varanopids. This study represents the first detailed tomographic study of the brain and inner ear of any basal eureptile. The new data described here reveal that the neuroanatomy of early sauropsids is far more complex and diverse than previously anticipated, and provide impetus for further exploration of the palaeoneuroanatomy of early amniotes.

show abstract

The fossil record of appendicular muscle evolution in Synapsida on the line to mammals: Part II—Hindlimb

Bishop,

Pierce

2023

The Anatomical Record

View full text Add to dashboard Cite

This paper is the second in a two‐part series that charts the evolution of appendicular musculature along the mammalian stem lineage, drawing upon the exceptional fossil record of extinct synapsids. Here, attention is focused on muscles of the hindlimb. Although the hindlimb skeleton did not undergo as marked a transformation on the line to mammals as did the forelimb skeleton, the anatomy of extant tetrapods indicates that major changes to musculature have nonetheless occurred. To better understand these changes, this study surveyed the osteological evidence for muscular attachments in extinct mammalian and nonmammalian synapsids, two extinct amniote outgroups, and a large selection of extant mammals, saurians, and salamanders. Observations were integrated into an explicit phylogenetic framework, comprising 80 character–state complexes covering all muscles crossing the hip, knee, and ankle joints. These were coded for 33 operational taxonomic units spanning >330 Ma of tetrapod evolution, and ancestral state reconstruction was used to evaluate the sequence of muscular evolution along the stem lineage from Amniota to Theria. The evolutionary history of mammalian hindlimb musculature was complex, nonlinear, and protracted, with several instances of convergence and pulses of anatomical transformation that continued well into the crown group. Numerous traits typically regarded as characteristically “mammalian” have much greater antiquity than previously recognized, and for some traits, most synapsids are probably more reflective of the ancestral amniote condition than are extant saurians. More broadly, this study highlights the utility of the fossil record in interpreting the evolutionary appearance of distinctive anatomies.

show abstract

First arboreal 'pelycosaurs' (Synapsida: Varanopidae) from the early Permian Chemnitz Fossil Lagerstätte, SE Germany, with a review of varanopid phylogeny

Cited by 53 publications

References 79 publications

A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny

A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny

Endocasts of the basal sauropsid Captorhinus reveal unexpected neurological diversity in early reptiles

The fossil record of appendicular muscle evolution in Synapsida on the line to mammals: Part II—Hindlimb

Contact Info

Product

Resources

About