Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals

  title={Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals},
  author={Zhe‐Xi Luo and Qiang Ji and Chong-xi Yuan},
Tribosphenic molars of basal marsupials and placentals are a major adaptation, with the protocone (pestle) of the upper molar crushing and grinding in the talonid basin (mortar) on the lower molar. [] Key Result Its shoulder girdle and limbs show fossorial features similar to those of mammaliaforms and monotremes, but different compared with those of the earliest-known Laurasian tribosphenic (boreosphenid) mammals. The find reveals a much greater range of dental evolution in Mesozoic mammals than in their…

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.

On the phylogenetic position of monotremes (Mammalia, Monotremata)

The Jurassic shuotheriid Pseudotribos shows a great plesiomorphic similarity to monotremes in the structure of the pectoral girdle, with a large interclavicle immovably connected to the clavicle.

Reappraisal of the Tribosphenidan Mammals from the Trinity Group (Aptian—Albian) of Texas and Oklahoma

The taxonomy of the tribosphenidan taxa known from the Trinity Group is updated and the premolar/molar count in each is established with more confidence, identifying strong morphological diversity within this assemblage of stem taxa.

The upper dentition and relationships of the enigmatic Australian Cretaceous mammal Kollikodon ritchiei

Pian, R., Archer, M., Hand, S.J., Beck, R.M.D. and Cody, A. 2016. The upper dentition and relationships of the enigmatic Australian Cretaceous mammal Kollikodon ritchiei. Memoirs of Museum Victoria

Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation

This functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica shows that pretribosphenic and tribosphenIC molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribospenic mammals.

The stem placental mammal Prokennalestes from the Early Cretaceous of Mongolia

Two Prokennalestes species are regarded as different species rather than sexual morphs of the same species based on rigorous phylogenetic analysis including a large set of known stem therian and stem placental taxa.

Evolution and function of the upper molar talon and its dietary implications in microbats

Results suggest that RFI of both the whole tooth and the trigon varies according to dietary groups, with frugivores having greater crushing function when compared with the other groups, and that the talon is primarily functioning in crushing during food breakdown.

A new mammal skull from the Lower Cretaceous of China with implications for the evolution of obtuse-angled molars and ‘amphilestid’ eutriconodonts

The phylogenetic analyses suggest that Juchilestes is most closely related to the Early Cretaceous Hakusanodon from Japan, in the same Eastern Asiatic geographic region; ‘amphilestids’ are not monophyletic; and eutriconodonts might not be a monophyletsic group, although this hypothesis must be further tested.

Postcranial Skeleton of the Cretaceous Mammal Akidolestes cifellii and Its Locomotor Adaptations

The postcranial skeleton of Akidolestes cifellii, a spalacotheroid species from the Lower Cretaceous Yixian Formation of northeastern China is described and suggests that a greater ecomorphological differentiation occurred in these stem therian mammals than previously thought and that ecological differentiation is a major pattern in early therian mammal evolution.

Tribosphenic Mammals from the Lower Cretaceous Cloverly Formation of Montana and Wyoming

ABSTRACT We report a diverse assemblage of tribosphenidan mammals from several localities in the Cloverly Formation (Lower Cretaceous, Albian) of Montana and Wyoming. This unit is of historical



Dual origin of tribosphenic mammals

Phylogenetic and morphometric analyses including these newly discovered taxa suggest a different interpretation: that mammals with tribosphenic molars are not monophyletic.

A probable pseudo-tribosphenic upper molar from the late Jurassic of China and the early radiation of the Holotheria

A three-cusped, mammalian upper molar recovered from the type locality of Shuotherium dongi Chow and Rich, 1982 in the Late Jurassic, Upper Shaximiao Formation Sichuan, China indicates a greater antiquity and diversity of the Tribosphenida than previously thought.

A new eutriconodont mammal and evolutionary development in early mammals

A Mesozoic eutriconodont nested within crown mammals that clearly illustrates this transition: the middle ear bones are connected to the mandible via an ossified Meckel’s cartilage, adding to the evidence of homoplasy of vertebral characters in the thoraco-lumbar transition and unfused lumbar ribs among early mammals.


A PAUP 4.0 analysis based on 277 cranial and postcranial characters has corroborated the position of Asfaltomylos as the most basal member of the Australosphenida, and suggests that australosphenidans are independent from boreospenidans.

A Cretaceous symmetrodont therian with some monotreme-like postcranial features

Analysis including this new taxon suggests that spalacotheroids evolved earlier in Eurasia and then dispersed to North America, in concordance with prevailing geodispersal patterns of several common mammalian groups during the Early Cretaceous period.

A Chinese triconodont mammal and mosaic evolution of the mammalian skeleton.

The derived pectoral girdle of this new triconodont indicates that homoplasies are as common in the postcranial skeleton as they are in the skull and dentition in the evolution of Mesozoic mammals.

An Aegialodontid Upper Molar and the Evolution of Mammal Dentition

A known upper molar of an aegialodontid mammal, Kielantherium, from the Early Cretaceous of Mongolia is reported, indicating the earliest stage in the development of boreosphenidan tribospheny has remained poorly understood.

Postcranial anatomy of Haldanodon exspectatus (Mammalia, Docodonta) from the Late Jurassic (Kimmeridgian) of Portugal and its bearing for mammalian evolution

A PAUP analysis based on 280 cranio-dental and postcranial characters corroborated the position of Haldanodon above morganucodontids and below Hadrocodium.

In quest for a phylogeny of Mesozoic mammals

A phylogeny of all major groups of Mesozoic mammals based on phylogenetic analyses of 46 taxa and 275 osteological and dental characters, using parsimony methods is proposed, suggesting that the “obtuse−angle symmetrodonts” are paraphyletic, and that they lack reliable and unambiguous synapomorphies.

The postcranial skeletons of the Triassic mammals Eozostrodon, Megazostrodon and Erythrotherium.

The purposes of this monograph are to describe the postcranial skeletons of the earliest known mammals, and to probe, in so far as possible by osteological study, biological questions concerning the