Evolution of the hypercarnivorous dentition in mammals (Metatheria, Eutheria) and its bearing on the development of tribosphenic molars

  title={Evolution of the hypercarnivorous dentition in mammals (Metatheria, Eutheria) and its bearing on the development of tribosphenic molars},
  author={Flor{\'e}al Sol{\'e} and Sandrine Ladev{\`e}ze},
  journal={Evolution \& Development},
One major innovation of mammals is the tribosphenic molar, characterized by the evolution of a neomorphic upper cusp (=protocone) and a lower basin (=talonid) that occlude and provide shearing and crushing functions. This type of molar is an evolutionarily flexible structure that enabled mammals to achieve complex dental adaptations. Among carnivorous mammals, hypercarnivory is a common trend that evolved several times among therians (marsupials, placentals, and stem relatives). Hypercarnivory… 
Morphological evolution in therocephalians breaks the hypercarnivore ratchet
  • N. Brocklehurst
  • Biology, Environmental Science
    Proceedings of the Royal Society B
  • 2019
Analysis of the ancestral therocephalian was a large macro-predator, with serrated teeth, elongated canines and robust lower jaws, and it is suggested that the hypercarnivore ratchet is a feature of mammalian evolution.
Allqokirus australis (Sparassodonta, Metatheria) from the early Palaeocene of Tiupampa (Bolivia) and the rise of the metatherian carnivorous radiation in South America
The dental morphology of Allqokirus australis is extremely similar to that of Patene simpsoni from the early Eocene of Itaboraí (Brazil) and presents distinct (although incipient) carnivorous adaptations.
Carnassiform notches improve the functional efficiency of bat molar shearing crests
Molar surface morphology of bats of 281 extant and extinct species in 5 archaic and 19 extant families is surveyed using scanning microscopy to identify structural structures “carnassiform notches” (CN) that increase the functional efficiency at sectioning chitin by increasing the effective length of a crest while maintaining the same cusp-to-cusp distance and precise occlusal relationships.
Cranial anatomy of Andinodelphys cochabambensis, a stem metatherian from the early Palaeocene of Bolivia
The present paper provides a thorough description of the dental, cranial, and dentary anatomy of A. cochabambensis, suggesting an independent arrival of pucadelphyids and sparassodonts to South America, which consequently must be present in North America in the Late Cretaceous.
Evolution of the Carnassial in Living Mammalian Carnivores (Carnivora, Didelphimorphia, Dasyuromorphia): Diet, Phylogeny, and Allometry
This work evaluates for the first time, in a quantitative way, which of the lower molars of the Metatheria (m3 or m4) is the best analogue to the m1 of Carnivora; the results indicated the m4 is thebest analogue.
Diversity and disparity of sparassodonts (Metatheria) reveal non-analogue nature of ancient South American mammalian carnivore guilds
It is found that sparassodonts had comparatively low ecomorphological disparity throughout their history and that South American carnivore palaeoguilds, as represented by that of Santa Cruz, Argentina, were unlike modern or fossil carnivore guilds of other continents in their lack of mesocarnivores and hypocarnivore.
A Nearly Complete Juvenile Skull of the Marsupial Sparassocynus derivatus from the Pliocene of Argentina, the Affinities of “Sparassocynids”, and the Diversification of Opossums (Marsupialia; Didelphimorphia; Didelphidae)
It is agreed that the appearance of carnivorously-adapted didelphids in South America during the late Miocene, including sparassocynins, is likely related to a decline in diversity of the sparassodonts at this time, and that the disappearance of these carnivorous- adaptations at the end of the Pliocene may have been due to the arrival of placental carnivorans from North America.
Eomakhaira molossus, A New Saber-Toothed Sparassodont (Metatheria: Thylacosmilinae) from the Early Oligocene (?Tinguirirican) Cachapoal Locality, Andean Main Range, Chile
The occurrence of Eomakhaira in strata of early Oligocene age from the Chilean Andes demonstrates that the stratigraphic range of thylacosmilines spanned almost 30 million years, far surpassing those of saber-toothed placental lineages.
Dental topographic and three‐dimensional geometric morphometric analysis of carnassialization in different clades of carnivorous mammals (Dasyuromorphia, Carnivora, Hyaenodonta)
An ancestral state reconstruction shows that this longitudinal elongation of the carnassial blade may be a plesiomorphic ancestral state for the Carnivora, which is different from the Dasyuromorphia and the Hyaenodonta.
The first North American Propterodon (Hyaenodonta: Hyaenodontidae), a new species from the late Uintan of Utah
  • S. Zack
  • Environmental Science, Biology
  • 2019
Identification of a North American species of Propterodon and an Asian Apataelurus increases the similarity of North American Uintan and Asian Irdinmanhan faunas and suggests that there was substantial exchange of carnivorous fauna during the late middle Eocene.


Evolution of the Tribosphenic Molar Pattern in Early Mammals, with Comments on the “Dual-Origin” Hypothesis
  • Brian M Davis
  • Environmental Science
    Journal of Mammalian Evolution
  • 2011
A series of morphotypes are presented that represent stepwise acquisition of characters of the molar crown, in an effort to clarify homologies and functional analogies among molars of tribosphenic and tribospenic-like mammals, as well as their putative sister groups.
Carnivorous dental adaptations in tribosphenic mammals and phylogenetic reconstruction
The molar morphology and structure of seven groups of flesh-eating mammals are compared and character states should be used with extreme care in reconstructing phylogeny and, when possible, associated to cranial features are discussed.
Jaw geometry and molar morphology in marsupial carnivores: analysis of a constraint and its macroevolutionary consequences
The resulting pattern from a macroevolutionary point of view is that, even in the absence of direct competition, Carnivora have had greater evolutionary “success” than Dasyurida.
Iterative evolution of hypercarnivory in canids (Mammalia: Carnivora): evolutionary interactions among sympatric predators
It is suggested that the iterative pattern of specialization of the lower molars for meat-slicing that is seen in all families of carnivores, past and present, is probably a result of intraspecific competition for food, perhaps among littermates.
Déjà vu: the evolution of feeding morphologies in the Carnivora
A survey of the fossil record indicates that large hypercarnivores evolve frequently, often in response to ecological opportunity afforded by the decline or extinction of previously dominant hyperc Carnivorous taxa.
Biting through constraints: cranial morphology, disparity and convergence across living and fossil carnivorous mammals
Contrary to previous studies, metatherian carnivores consistently exhibited disparity which exceeded that of the much more speciose eutherian carnivore radiations, refuting the hypothesis that developmental constraints have limited the morphological evolution of the marsupial cranium.
Ontogeny of postcanine tooth form in the ferret, Mustela putorius (Carnivora: Mammalia), and the evolution of dental diversity within the mustelidae
Dental development within the ferret is described through study of the form of the carnassial teeth and the upper first molar at progressive growth stages and suggests that carnivoran species may share a common path of early development that specifies the ontogeny of homologous tooth features and that in later stages developmental differences result in species‐specific tooth forms.
Roles of dental development and adaptation in rodent evolution.
This study finds that overexpression of Eda or Edar is sufficient to produce the longitudinal crests defining stephanodonty in transgenic laboratory mice, and demonstrates how combining development and function can help to evaluate adaptive scenarios in the evolution of new morphologies.
Nonindependence of mammalian dental characters
It is reported that, at least developmentally, most dental characters may be nonindependent, and most aspects of tooth shape have the developmental potential for correlated changes during evolution which may, if not taken into account, obscure phylogenetic history.
An Early Cretaceous Tribosphenic Mammal and Metatherian Evolution
New data from this fossil support the view that Asia was likely the center for the diversification of the earliest metatherians and eutherians during the Early Cretaceous.