First evidence of denticulated dentition in teleosaurid crocodylomorphs

Young, Mark T.; Beatty, Brian L.; Brusatte, Stephen L.; Steel, Lorna

doi:10.4202/app.00002.2013

Cited by 8 publications

(14 citation statements)

References 39 publications

(79 reference statements)

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“…At least at the crown apex, it is evident that the anastomosed pattern transfers over the carinae which forms false denticles (="false ziphodont condition" sensu Prasad & De Lapparent de Broin, 2002). Therefore, we tentatively interpret the carina as having superficial crenulations along its length, but not true denticles (sensu Young et al, 2015; character 80, state 0).…”

Section: The 5th Maxillary Toothmentioning

confidence: 82%

Australia’s prehistoric ‘swamp king’: revision of the Plio-Pleistocene crocodylian genusPallimnarchusde Vis, 1886

Ristevski

Yates²,

Price

et al. 2020

PeerJ

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The crocodylian fossil record from the Cenozoic of Australasia is notable for its rich taxonomic diversity, and is primarily represented by members of the clade Mekosuchinae. Reports of crocodylian fossils from Australia date back to the late nineteenth century. In 1886, Charles Walter de Vis proposed the name Pallimnarchus pollens for crocodylian fossils from southeast Queensland—the first binomen given to an extinct crocodylian taxon from Australia. Pallimnarchus has come to be regarded as a large, broad-snouted crocodylian from Australia’s Plio-Pleistocene, and numerous specimens, few of which are sufficiently complete, have been assigned to it by several authors throughout the twentieth century. In the late 1990s, the genus was expanded to include a second species, Pallimnarchus gracilis. Unfortunately, the original syntype series described as Pallimnarchus pollens is very fragmentary and derives from more than one taxon, while a large part of the subsequently selected lectotype specimen is missing. Because descriptions and illustrations of the complete lectotype do not reveal any autapomorphic features, we propose that Pallimnarchus pollens should be regarded as a nomen dubium. Following this decision, the fossil material previously referred to Pallimnarchus is of uncertain taxonomic placement. A partial skull, formerly assigned to Pallimnarchus pollens and known as ‘Geoff Vincent’s specimen’, possesses many features of diagnostic value and is therefore used as basis to erect a new genus and species—Paludirex vincenti gen. et sp. nov. A comprehensive description is given for the osteology of ‘Geoff Vincent’s specimen’ as well as aspects of its palaeoneurology, the latter being a first for an extinct Australian crocodyliform. The newly named genus is characterized by a unique combination of premaxillary features such as a distinctive arching of the anterior alveolar processes of the premaxillae, a peculiar arrangement of the first two premaxillary alveoli and a large size disparity between the 3rd and 4th premaxillary alveoli. These features presently allow formal recognition of two species within the genus, Paludirex vincenti and Paludirex gracilis comb. nov., with the former having comparatively more robust rostral proportions than the latter. The Paludirex vincenti holotype comes from the Pliocene Chinchilla Sand of the Darling Downs, south-eastern Queensland, whereas the material assigned to Paludirex gracilis is from the Pleistocene of Terrace Site Local Fauna, Riversleigh, northwest Queensland. Phylogenetic analyses recover Paludirex vincenti as a mekosuchine, although further cladistic assessments are needed to better understand the relationships within the clade.

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Section: The 5th Maxillary Toothmentioning

confidence: 82%

Australia’s prehistoric ‘swamp king’: revision of the Plio-Pleistocene crocodylian genusPallimnarchusde Vis, 1886

Ristevski

Yates²,

Price

et al. 2020

PeerJ

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“…However, recently a generalized 'macrophagous' diet has been posited for 'S.' obtusidens based on tooth morphology, particularly the presence of serrations [13].…”

Section: Introductionmentioning

confidence: 99%

“…Scanning electron microscopy (SEM) and macrophotographic investigation of 'S.' obtusidens dentition find two types of tooth serrations: false denticles and true denticles [13]. False denticles are defined as being formed by the superficial enamel contacting the carinal keel, as often occurs when enamel ornaments such as ridges intersect with the carina [14].…”

Section: Introductionmentioning

confidence: 99%

“…False denticles are defined as being formed by the superficial enamel contacting the carinal keel, as often occurs when enamel ornaments such as ridges intersect with the carina [14]. True denticles are defined following Young et al [13]: 'true serrations are discrete morphological units on, or along, the carinae which are not formed by the surface enamel ornamentation'. (Note that we do not use a histological definition of denticles, namely that the underlying dentine contributes to them, owing to the destructive nature of the analyses needed to confirm this.)…”

Section: Introductionmentioning

confidence: 99%

“…This occurs in taxa with incipient denticles, such as in 'S.' obtusidens [13] and the metriorhynchid thalattosuchians 'Metriorhynchus' brachyrhynchus, Tyrannoneustes lythrodectikos and Torvoneustes carpenteri [15,16]. The definition used herein is a revised version of that used by Prasad & Broin [14], as incipient denticles are not always clearly individualized, and may not form a contiguous series.…”

Section: Introductionmentioning

confidence: 99%

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Tooth serration morphologies in the genus Machimosaurus(Crocodylomorpha, Thalattosuchia) from the Late Jurassic of Europe

et al. 2014

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Machimosaurus was a large-bodied durophagous/chelonivorous genus of teleosaurid crocodylomorph that lived in shallow marine and brackish ecosystems during the Late Jurassic. Among teleosaurids, Machimosaurus and its sister taxon ‘Steneosaurus’ obtusidens are characterized by having foreshortened rostra, proportionally enlarged supratemporal fenestrae and blunt teeth with numerous apicobasal ridges and a shorter anastomosed ridged pattern in the apical region. A recent study on ‘S.’ obtusidens dentition found both true denticles and false serrations (enamel ridges which contact the carinae). Here, we comprehensively describe and figure the dentition of Machimosaurus, and find that Machimosaurus buffetauti and Machimosaurus hugii have four types of serration or serration-like structures, including both denticles and false denticles on the carinae. The denticles are irregularly shaped and are not always discrete units, whereas the false denticles caused by the interaction between the superficial enamel ridges and the carinae are restricted to the apical region. Peculiarly, the most ‘denticle-like’ structures are discrete, bulbous units on the apicobasal and apical anastomosed ridges of M. hugii. These ‘pseudo-denticles’ have never, to our knowledge, previously been reported among crocodylomorphs, and their precise function is unclear. They may have increased the surface area of the apical region and/or strengthened the enamel, both of which would have been advantageous for a durophagous taxon feeding on hard objects such as turtles.

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Revision of the Late Jurassic teleosaurid genusMachimosaurus(Crocodylomorpha, Thalattosuchia)

et al. 2014

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Machimosaurus was a large-bodied genus of teleosaurid crocodylomorph, considered to have been durophagous/chelonivorous, and which frequented coastal marine/estuarine ecosystems during the Late Jurassic. Here, we revise the genus based on previously described specimens and revise the species within this genus. We conclude that there were three European Machimosaurus species and another taxon in Ethiopia. This conclusion is based on numerous lines of evidence: craniomandibular, dental and postcranial morphologies; differences in estimated total body length; geological age; geographical distribution; and hypothetical lifestyle. We re-diagnose the type species Machimosaurus hugii and limit referred specimens to only those from Upper Kimmeridgian–Lower Tithonian of Switzerland, Portugal and Spain. We also re-diagnose Machimosaurus mosae, demonstrate that it is an available name and restrict the species to the uppermost Kimmeridgian–lowermost Tithonian of northeastern France. We re-diagnose and validate the species Machimosaurus nowackianus from Harrar, Ethiopia. Finally, we establish a new species, Machimosaurus buffetauti, for the Lower Kimmeridgian specimens of France and Germany (and possibly England and Poland). We hypothesize that Machimosaurus may have been analogous to the Pliocene–Holocene genus Crocodylus in having one large-bodied taxon suited to traversing marine barriers and additional, geographically limited taxa across its range.

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First evidence of denticulated dentition in teleosaurid crocodylomorphs

Cited by 8 publications

References 39 publications

Australia’s prehistoric ‘swamp king’: revision of the Plio-Pleistocene crocodylian genusPallimnarchusde Vis, 1886

Australia’s prehistoric ‘swamp king’: revision of the Plio-Pleistocene crocodylian genusPallimnarchusde Vis, 1886

Tooth serration morphologies in the genus Machimosaurus(Crocodylomorpha, Thalattosuchia) from the Late Jurassic of Europe

Revision of the Late Jurassic teleosaurid genusMachimosaurus(Crocodylomorpha, Thalattosuchia)

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