A new Early Cretaceous tritylodontid (Synapsida, Cynodontia, Mammaliamorpha) from the Kuwajima Formation (Tetori Group) of central Japan

Matsuoka, Hiroaki; Kusuhashi, Nao; Corfe, Ian J.

doi:10.1080/02724634.2016.1112289

Cited by 32 publications

(31 citation statements)

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“…Together, these are thought to represent the wide, stable, vegetated floodplain of a meandering river system, with a humid environment [ 40 – 41 ]. All of these facies have yielded vertebrate remains, including dinosaurs [ 42 – 43 ], pterosaurs [ 44 ], mammals [ 45 – 46 ], tritylodonts [ 47 – 49 ], lizards [ 50 – 54 ], fish [ 55 – 57 ], turtles [ 58 ], turtle eggshells [ 59 ], choristoderes [ 60 – 61 ], and rare frogs [ 62 ]. To date, more than 2500 specimens have been recorded from this locality.…”

Section: Geological Settingmentioning

confidence: 99%

The first record of albanerpetontid amphibians (Amphibia: Albanerpetontidae) from East Asia

Matsumoto¹,

Evans²

2018

PLoS ONE

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Albanerpetontids are an enigmatic fossil amphibian group known from deposits of Middle Jurassic to Pliocene age. The oldest and youngest records are from Europe, but the group appeared in North America in the late Early Cretaceous and radiated there during the Late Cretaceous. Until now, the Asian record has been limited to fragmentary specimens from the Late Cretaceous of Uzbekistan. This led to speculation that albanerpetontids migrated into eastern Asia from North America in the Albian to Cenomanian interval via the Beringian land bridge. However, here we describe albanerpetontid specimens from the Lower Cretaceous Kuwajima Formation of Japan, a record that predates their first known occurrence in North America. One specimen, an association of skull and postcranial bones from a single small individual, permits the diagnosis of a new taxon. High Resolution X-ray Computed Microtomography has revealed previously unrecorded features of albanerpetontid skull morphology in three dimensions, including the presence of a supraoccipital and epipterygoids, neither of which occurs in any known lissamphibian. The placement of this new taxon within the current phylogenetic framework for Albanerpetontidae is complicated by a limited overlap of comparable elements, most notably the non-preservation of the premaxillae in the Japanese taxon. Nonetheless, phylogenetic analysis places the new taxon closer to Albanerpeton than to Anoualerpeton, Celtedens, or Wesserpeton, although Bootstrap support values are weak. The results also question the monophyly of Albanerpeton as currently defined.

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Section: Geological Settingmentioning

confidence: 99%

The first record of albanerpetontid amphibians (Amphibia: Albanerpetontidae) from East Asia

Matsumoto¹,

Evans²

2018

PLoS ONE

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“…A recent study analyzed the evolution of the IOF in nonmammaliaform cynodonts using CT‐data (Benoit et al, ). They reported that a change in the pattern of the infraorbital nerve occurred in Early Jurassic tritylodontids and tritheledontids, the late surviving nonmammalian cynodont groups that are more closely related to mammals (Matsuoka et al, ; Rodrigues et al, ). Although multiple foramina were present, only one was likely to transmit the infraorbital nerve, as the other openings had an independent origin in the orbit.…”

Section: Introductionmentioning

confidence: 99%

Good Vibrations: The Evolution of Whisking in Small Mammals

Muchlinski

Wible

Corfe

et al. 2018

The Anatomical Record

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While most mammals have whiskers, some tactile specialistsmainly small, nocturnal, and arboreal species-can actively move their whiskers in a symmetrical, cyclic movement called whisking. Whisking enables mammals to rapidly, tactually scan their environment to efficiently guide locomotion and foraging in complex habitats. The muscle architecture that enables whisking is preserved from marsupials to primates, prompting researchers to suggest that a common ancestor might have had moveable whiskers. Studying the evolution of whisker touch sensing is difficult, and we suggest that measuring an aspect of skull morphology that correlates with whisking would enable comparisons between extinct and extant mammals. We find that whisking mammals have larger infraorbital foramen (IOF) areas, which indicates larger infraorbital nerves and an increase in sensory acuity. While this relationship is quite variable and IOF area cannot be used to solely predict the presence of whisking, whisking mammals all have large IOF areas. Generally, this pattern holds true regardless of an animal's substrate preferences or activity patterns. Data from fossil mammals and ancestral character state reconstruction and tracing techniques for extant mammals suggest that whisking is not the ancestral state for therian mammals. Instead, whisking appears to have evolved independently as many as seven times across the clades Marsupialia, Afrosoricida, Eulipotyphla, and Rodentia, with Xenarthra the only placental superordinal clade lacking whisking species. However, the term whisking only captures symmetrical and rhythmic movements of the whiskers, rather than all possible whisker movements, and early mammals may still have had moveable whiskers. Anat Rec, 303:89-99, 2020.

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“…The Prozostrodontia contain several unranked taxa (e.g., Prozostrodon , Therioherpeton , Alemoatherium , Botucaraitherium ), as well as two well-known major clades, the Tritylodontidae and Tritheledontidae, both closely related to Mammaliaformes ( Hopson & Kitching, 2001 ; Liu & Olsen, 2010 ; Soares, Martinelli & Oliveira, 2014 ; Martinelli et al, 2017a ; Martinelli et al, 2017b ). The Tritylodontidae are a group of medium-sized (basal skull length, BSL ∼50–250 mm) highly specialized herbivorous prozostrodontians that arose during the Late Triassic and went extinct during the Early Cretaceous (e.g., Clark & Hopson, 1985 ; Sues, 1986 ; Matsuoka, Kusuhashi & Corfe, 2016 ). The Tritheledontidae are a group of small (BSL ∼30–70 mm), faunivorous/frugivorous forms that existed from the Late Triassic to Early Jurassic ( Kemp, 2005 ; Gow, 1980 ; Martinelli et al, 2005 ; Martinelli & Rougier, 2007 ; Soares, Schultz & Horn, 2011 ).…”

Section: Introductionmentioning

confidence: 99%

Osteohistology of Late Triassic prozostrodontian cynodonts from Brazil

Botha‐Brink

Soares

Martinelli

2018

PeerJ

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The Prozostrodontia includes a group of Late Triassic-Early Cretaceous eucynodonts plus the clade Mammaliaformes, in which Mammalia is nested. Analysing their growth patterns is thus important for understanding the evolution of mammalian life histories. Obtaining material for osteohistological analysis is difficult due to the rare and delicate nature of most of the prozostrodontian taxa, much of which comprises mostly of crania or sometimes even only teeth. Here we present a rare opportunity to observe the osteohistology of several postcranial elements of the basal prozostrodontid Prozostrodon brasiliensis, the tritheledontid Irajatherium hernandezi, and the brasilodontids Brasilodon quadrangularis and Brasilitherium riograndensis from the Late Triassic of Brazil (Santa Maria Supersequence). Prozostrodon and Irajatherium reveal similar growth patterns of rapid early growth with annual interruptions later in ontogeny. These interruptions are associated with wide zones of slow growing bone tissue. Brasilodon and Brasilitherium exhibit a mixture of woven-fibered bone tissue and slower growing parallel-fibered and lamellar bone. The slower growing bone tissues are present even during early ontogeny. The relatively slower growth in Brasilodon and Brasilitherium may be related to their small body size compared to Prozostrodon and Irajatherium. These brasilodontids also exhibit osteohistological similarities with the Late Triassic/Early Jurassic mammaliaform Morganucodon and the Late Cretaceous multituberculate mammals Kryptobaatar and Nemegtbaatar. This may be due to similar small body sizes, but may also reflect their close phylogenetic affinities as Brasilodon and Brasilitherium are the closest relatives to Mammaliaformes. However, when compared with similar-sized extant placental mammals, they may have grown more slowly to adult size as their osteohistology shows it took more than one year for growth to attenuate. Thus, although they exhibit rapid juvenile growth, the small derived, brasilodontid prozostrodontians still exhibit an extended growth period compared to similar-sized extant mammals.

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A new Early Cretaceous tritylodontid (Synapsida, Cynodontia, Mammaliamorpha) from the Kuwajima Formation (Tetori Group) of central Japan

Cited by 32 publications

References 50 publications

The first record of albanerpetontid amphibians (Amphibia: Albanerpetontidae) from East Asia

The first record of albanerpetontid amphibians (Amphibia: Albanerpetontidae) from East Asia

Good Vibrations: The Evolution of Whisking in Small Mammals

Osteohistology of Late Triassic prozostrodontian cynodonts from Brazil

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