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Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals.
Nature. 2007 Nov 01; 450(7166):93-7.Nat

Abstract

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. The extinct pseudo-tribosphenic mammals have a reversed tribosphenic molar in which a pseudo-talonid is anterior to the trigonid, to receive the pseudo-protocone of the upper molar. The pseudo-protocone is analogous to the protocone, but the anteriorly placed pseudo-talonid is opposite to the posterior talonid basin of true tribosphenic mammals. Here we describe a mammal of the Middle Jurassic period with highly derived pseudo-tribosphenic molars but predominantly primitive mandibular and skeletal features, and place it in a basal position in mammal phylogeny. 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 extant descendants, and strengthens the hypothesis of homoplasy of 'tribosphenic-like' molars among mammals.

Authors+Show Affiliations

Carnegie Museum of Natural History, Pittsburgh, Pennsylvania 15213, USA. luoz@carnegiemnh.orgNo affiliation info availableNo affiliation info available

Pub Type(s)

Historical Article
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

17972884

Citation

Luo, Zhe-Xi, et al. "Convergent Dental Adaptations in Pseudo-tribosphenic and Tribosphenic Mammals." Nature, vol. 450, no. 7166, 2007, pp. 93-7.
Luo ZX, Ji Q, Yuan CX. Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals. Nature. 2007;450(7166):93-7.
Luo, Z. X., Ji, Q., & Yuan, C. X. (2007). Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals. Nature, 450(7166), 93-7.
Luo ZX, Ji Q, Yuan CX. Convergent Dental Adaptations in Pseudo-tribosphenic and Tribosphenic Mammals. Nature. 2007 Nov 1;450(7166):93-7. PubMed PMID: 17972884.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals. AU - Luo,Zhe-Xi, AU - Ji,Qiang, AU - Yuan,Chong-Xi, PY - 2007/04/03/received PY - 2007/09/03/accepted PY - 2007/11/2/pubmed PY - 2007/12/6/medline PY - 2007/11/2/entrez SP - 93 EP - 7 JF - Nature JO - Nature VL - 450 IS - 7166 N2 - 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. The extinct pseudo-tribosphenic mammals have a reversed tribosphenic molar in which a pseudo-talonid is anterior to the trigonid, to receive the pseudo-protocone of the upper molar. The pseudo-protocone is analogous to the protocone, but the anteriorly placed pseudo-talonid is opposite to the posterior talonid basin of true tribosphenic mammals. Here we describe a mammal of the Middle Jurassic period with highly derived pseudo-tribosphenic molars but predominantly primitive mandibular and skeletal features, and place it in a basal position in mammal phylogeny. 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 extant descendants, and strengthens the hypothesis of homoplasy of 'tribosphenic-like' molars among mammals. SN - 1476-4687 UR - https://www.unboundmedicine.com/medline/citation/17972884/Convergent_dental_adaptations_in_pseudo_tribosphenic_and_tribosphenic_mammals_ L2 - https://doi.org/10.1038/nature06221 DB - PRIME DP - Unbound Medicine ER -