On<i>Chaliminia musteloides</i>(Eucynodontia: Tritheledontidae) from the Late Triassic of Argentina, and a phylogeny of Ictidosauria

Martinelli, Agustín G.; Rougier, Guillermo W.

doi:10.1671/0272-4634(2007)27[442:ocmetf]2.0.co;2

Cited by 63 publications

(110 citation statements)

References 49 publications

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“…Some very thin and small bone fragments dispersed in the interpterygoid vacuity area of UFRGS-PV-0596-T could indicate that the aperture was covered by an incipient sheet of bone. Among epicynodonts, the interpterygoid vacuities were observed in juveniles specimens of Thrinaxodon (Martinelli and Rougier 2007), and among eucynodonts this feature is present in juveniles of Probelesodon and Lumkuia, in adult specimens of tritheledontids, as Diarthrognathus (Crompton 1958), Chaliminia (Bonaparte 1980, Martinelli andRougier 2007) and Pachygenelus (Hopson and Barghusen 1986), and in Brasilodon and Brasilitherium . The presence of the interpterygoid vacuities in epicynodonts has been interpreted as a retention of a primitive character or a reversion to a plesiomorphic therapsid condition, which was still conserved in the pre-epicynodonts Dvinia and Procynosuchus (Hopson and Barghusen 1986).…”

Section: Palatementioning

confidence: 99%

“…In the root of the zygomatic arch, the maxilla contacts posteriorly the jugal and medially the lacrimal. The lacrimal of Riograndia occupies a large area in the root of the zygomatic arch as in Chaliminia (Bonaparte 1980, Martinelli andRougier 2007), Diarthrognathus (Crompton 1958) and Pachygenelus (Bonaparte et al 2003). The lacrimal-jugal contact in the root of the zygomatic arch is much reduced in lateral view due to the presence of the zygomatic process of maxilla that covers the jugal laterally.…”

Section: Squamosalmentioning

confidence: 99%

“…According to Kemp (1979), the vacuities are a remnant structure related to some skull kinetism of basal therapsids still present in these Permian cynodonts. Martinelli and Rougier (2007) have considered that the re-acquisition of the interpterygoid vacuities in the derived nonmammaliaform cynodonts, which bear a high resemblance with the pattern present in most basal forms (e.g. Procynosuchus) and in immature individuals of more derived forms (e.g.…”

Section: Palatementioning

confidence: 99%

“…Martinelli et al (2005) showed Riograndia to be the most basal taxon within Tritheledontidae (Fig. 2a), while Martinelli and Rougier (2007) placed Riograndia as the most basal taxon of the monophyletic Ictidosauria Clade, and as sister taxon of the most inclusive Tritheledontidae, composed by Irajatherium, Chaliminia,Elliotherium,Pachygenelus,Diarthrognathus,and Tritheledon (Fig. 2b).…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the authors support the close relationship between Riograndia and Pachygenelus. They emphasize that the possibility of a monophyletic Ictidosauria (sensu Martinelli and Rougier 2007) group cannot be excluded and needs additional tests. In any case, Riograndia is closely related to other tritheledontids (or tritheledontians) than other non-mammaliaform cynodonts; the new materials presented here reinforce this phylogenetic hypothesis.…”

Section: Introductionmentioning

confidence: 99%

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New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications

Soares

Schultz

Horn

2011

An. Acad. Bras. Ciênc.

106

101

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The tritheledontid Riograndia guaibensis was the first cynodont described for the "Caturrita Formation" fauna from the Late Triassic of southern Brazil (Santa Maria 2 Sequence). The type materials did not preserve anatomical information regarding braincase, occiput, basicranium, zygomatic arch, postdentary bones and craniomandibular joint. Here new materials are described and supply the missing information. Riograndia shows a suite of important anatomical features quite derived among the non-mammaliaform eucynodonts, such as the partial closure of the medial orbital wall and braincase, extensive secondary osseous palate, wide primary palate, basicranium with jugular foramen separated from the periphery of fenestra rotunda, narrow zygomatic arch and much reduced postdentary bones. Many of these features constitute synapomorphies shared only with the other members of mammaliamorpha. Thus, the almost complete cranial, mandibular and dental information from the new fossils of Riograndia can bring a significant improve in the understanding of the anatomy and phylogenetic relationships of the tritheledontids and help to elucidate the transformational steps involved in the cynodont-mammal transition. Additionally, Riograndia is a key taxon in refining the "Caturrita Formation" biostratigraphy, enabling the connection of several fossiliferous outcrops that have a rich tetrapod fauna that can be correlated with other Triassic faunas from Gondwana and Laurasia.

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Section: Palatementioning

confidence: 99%

Section: Squamosalmentioning

confidence: 99%

Section: Palatementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications

Soares

Schultz

Horn

2011

An. Acad. Bras. Ciênc.

106

101

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A new specimen provides insights into the anatomy of Irajatherium hernandezi, a poorly known probainognathian cynodont from the Late Triassic of southern Brazil

Kerber

Martinelli

Müller

et al. 2021

The Anatomical Record

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Irajatherium hernandezi is a poorly known non‐mammaliaform cynodont from the Late Triassic of southern Brazil. A new specimen of this cynodont was found in recent fieldwork to the type‐locality, Sesmaria do Pinhal (Candelária), providing new insights into the anatomy of this mammalian forerunner. This specimen comprises a partial skull preserving the left canine, two left and three right postcanines, and an isolated exoccipital; the left dentary with the canine and postcanines; a fragment of the right dentary; the proximal portion of the left partial humerus; the right scapula; and indeterminate fragments. Based on new material, it is here suggested that I. hernandezi presents: a rostrum broad and short, possibly long as the temporal region; three foramina on the lateral surface of the maxilla, that could correspond to the external openings of the rostral alveolar, infraorbital, and zygomaticofacial canals; a slender zygomatic arch and an absent postorbital bar; a posteriorly wide temporal fossa; a long secondary palate, slightly surpassing the level of the last postcanine tooth; the cerebral hemispheres of the cranial endocast divided by a median sulcus; the scapular blade long and straight, and the postscapular fossa absent in lateral aspect. Finally, I. hernandezi and other tritheledontids were included in a phylogenetic analysis of Eucynodontia. The analysis recovered unresolved relationships for ictidosaurs/tritheledontids, nested within a polytomy with Tritylodontidae and a clade composed by Pseudotherium argentinus, Botucaraitherium belarminoi, Brasilodon quadrangularis, and Mammaliaformes.

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First CT‐assisted study of the palate and postcrania of Diarthrognathus broomi (Cynodontia, Probainognathia)

Lund,

Norton,

Benoit

2023

The Anatomical Record

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Diarthrognathus broomi is a transitional taxon between non‐mammaliaform cynodonts and Mammaliaformes that occurred during the Late Triassic to Early Jurassic. All known specimens of Diarthrognathus represent juveniles, and the postcrania have not been thoroughly described. The palatal, basicranial and postcranial elements of the referred specimen NMQR 1535 are described here for the first time using 3D reconstructions generated from X‐ray micro‐computed tomography (μCT) data. The presence of a large interpterygoid vacuity, open medial suture between the vomers and medially unossified secondary palate all support the interpretation that NMQR 1535 is a juvenile. In addition, Diarthrognathus uniquely possesses “suborbital” vacuities, which distinguishes it from every other known cynodont. The presence of an ossified olecranon process, among other features, suggests that Diarthrognathus may have been a scratch‐digger. The postcranial skeleton of Diarthrognathus appears to be more plesiomorphic than tritylodontids, Brasilodon and other tritheledontids as, among other traits, it retains amphicoelous vertebrae. However, this taxon also displays synapomorphies with the more derived cynodonts, such as the mammalian pattern of neurocentral ossification and possible absence of an ectepicondylar foramen.

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OnChaliminia musteloides(Eucynodontia: Tritheledontidae) from the Late Triassic of Argentina, and a phylogeny of Ictidosauria

Cited by 63 publications

References 49 publications

New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications

New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications

A new specimen provides insights into the anatomy of Irajatherium hernandezi, a poorly known probainognathian cynodont from the Late Triassic of southern Brazil

First CT‐assisted study of the palate and postcrania of Diarthrognathus broomi (Cynodontia, Probainognathia)

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