Topic
Didelphodon
About: Didelphodon is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 81 citations.
Papers
Journal Article•
TL;DR: In addition, an incomplete upper dentition of Didelphodon coyi from the Scollard Formation extends the range of this species into the Lancian, co−eval with D. vorax and D. padanicus.
Abstract: Previously undescribed specimens of stagodontid marsupials from Late Cretaceous deposits in Alberta, Canada, reveal new information concerning the upper dentition of Eodelphis spp. and the lower dentition of Didelphodon coyi. Addition− ally, an incomplete upper dentition of D. coyi from the Scollard Formation extends the range of this species into the Lancian, co−eval with D. vorax and D. padanicus. Stagodontids are in accord with other North American Late Cretaceous marsupials for which the appropriate parts are known in lacking diastemata between the canines and the molars while pos− sessing well−developed palatal vacuities, implying that these morphologies characterized ancestral marsupials. If so, the diastema between P1 and P2 in the Asian middle Early Cretaceous “metatherian” Sinodelphys szalayi is convergent on that in Cenozoic didelphids, and the absence of palatal vacuities in South American Paleogene and Neogene borhyaenids is derived, representing a paedomorphic truncation of development. Claims that the Asian Late Cretaceous “metatherian” Deltatheridium pretrituberculare had a marsupial−like dental replacement pattern are tautological, deduced from an a pri− ori acceptance of a marsupial model of replacement to the exclusion of other, no less realistic, alternatives. The new speci− mens of Didelphodon coyi demonstrate that upper and lower premolars occluded broadly, implying that the inflated lin− gual lobes characteristic of Didelphodon premolars evolved primarily as a crushing mechanism, not for passive protec− tion of the gums. Recent speculations that stagodontids were aquatic are not based on credible morphologic or taphonomic evidence and are dismissed, as is speculation that the Judithian species of Eodelphis are sexual morphs of a single species. Current knowledge of Didelphodon compels correction of numerous errors concerning its morphology as presented in recent analyses of marsupial relationships.
39 citations
TL;DR: This work describes two new dentary fossils referable to E. cutleri and test the evolutionary hypothesis by applying beam theory to estimate bending force capabilities of 22 dentaries of Cretaceous stagodontids and other metatherians, implying that some morphological changes associated with durophagy evolved twice within this clade.
Abstract: The Stagodontidae include the largest metatherians known from the Cretaceous of North America. Of the recognized species of the stagodontid genus Eodelphis, E. cutleri is larger and has a more robust dentary, more inflated premolars, and third premolars specialized for crushing, as opposed to the more gracile E. browni. These differences have led to the hypothesis that an E. cutleri-like ancestor gave rise to Didelphodon—another, mostly younger, stagodontid, which has been interpreted as a durophagous predator-scavenger. If correct, E. cutleri would be expected to show more morphological adaptation toward durophagy than E. browni does. Here, we describe two new dentary fossils referable to E. browni and test the evolutionary hypothesis by applying beam theory to estimate bending force capabilities of 22 dentaries of Cretaceous stagodontids and other metatherians. The resulting diversity of bending force profiles of the sampled dentaries implies that Cretaceous metatherians had a wide range of feeding behaviors. Among the stagodontids, E. cutleri has a mediolateral bending force profile of the dentary that is more similar to that of Didelphodon than it is to that of E. browni; whereas its dorsoventral bending force profile is more similar to that of E. browni. These results indicate that anteriorly the dentary of E. cutleri was capable of resisting high torsional stresses from hard-object feeding but lacked other dorsoventral buttressing associated with exceptionally high bite forces of Didelphodon. Our results imply that some morphological changes associated with durophagy evolved twice within this clade, independently in E. cutleri and Didelphodon.
TL;DR: The phylogenetic analysis indicates that marsupials or their closest relatives evolved in North America, as part of a Late Cretaceous diversification of metatherians, and later dispersed to South America.
Abstract: Marsupial mammal relatives (stem metatherians) from the Mesozoic Era (252–66 million years ago) are mostly known from isolated teeth and fragmentary jaws. Here we report on the first near-complete skull remains of a North American Late Cretaceous metatherian, the stagodontid Didelphodon vorax. Our phylogenetic analysis indicates that marsupials or their closest relatives evolved in North America, as part of a Late Cretaceous diversification of metatherians, and later dispersed to South America. In addition to being the largest known Mesozoic therian mammal (node-based clade of eutherians and metatherians), Didelphodon vorax has a high estimated bite force and other craniomandibular and dental features that suggest it is the earliest known therian to invade a durophagous predator–scavenger niche. Our results broaden the scope of the ecomorphological diversification of Mesozoic mammals to include therian lineages that, in this case, were linked to the origin and evolution of marsupials. The early fossil record of metatherian mammals, the group including marsupials, is limited. Here, Wilson and colleagues describe a fossil skull of the Late Cretaceous metatherianDidelphodon vorax, providing insight into the ecology of this species as well as the North American origin of marsupials.
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Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2016 | 1 |
| 2006 | 1 |