Synchrotron X‐ray micro‐computed tomography enhances our knowledge of the skull anatomy of a Late Triassic ecteniniid cynodont with hypercanines

The Anatomical Record, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 13, 2025

Abstract Hypercanines, or hypertrophied canines, are observed in a wide range of both extinct and extant synapsids. In non‐mammaliaform cynodonts, the Permo‐Triassic forerunners mammals, long canines not uncommon, appearing several unrelated taxa within clade. Among them is Trucidocynodon riograndensis , carnivorous ecteniniid cynodont from Late Triassic Brazil, which exhibits specialized dentition, including spear‐shaped incisors, very narrow sectorial postcanines with distally oriented cusps, all have finely serrated margins. Recent synchrotron X‐ray micro‐computed tomography large specimen (CAPPA/UFSM 0029; Várzea do Agudo site, Brazil) provides new insights into its lower jaw as well offers first digital endocast an ecteniniid. Our study reveals presence (i) putatively opened‐root adult stage possible unresorbed remnant old canine, may indicate that stopped replacing canines; (ii) longer than upper and, occlusion, were kept inside deep paracanine fossae perforated dorsal surface rostrum; (iii) diastema between incisors absent holotype; (iv) advanced brain structures, such absence pineal body, cerebral hemispheres divided by interhemispheric sulcus expanded laterally, higher encephalization quotient prozostrodonts, reflecting homoplastic evolution relative sizes lineages. Finally, abundance omnivorous species at where was found—including archosauriforms Dynamosuchus collisensis Stenoscelida aurantiacus —suggests diverse predator guild warrants further investigation paleoecological perspective.

Language: Английский

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A jaw-dropping discovery about early mammals

Nature, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 25, 2024

Language: Английский

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