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A new mammaliaform from the early Jurassic and evolution of mammalian characteristics.
Science. 2001 May 25; 292(5521):1535-40.Sci

Abstract

A fossil from the Early Jurassic (Sinemurian, approximately 195 million years ago) represents a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts. It has an enlarged cranial cavity, but no postdentary trough on the mandible, indicating separation of the middle ear bones from the mandible. This extends the earliest record of these crucial mammalian features by some 45 million years and suggests that separation of the middle ear bones from the mandible and the expanded brain vault could be correlated. It shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups. With an estimated body weight of only 2 grams, its coexistence with other larger mammaliaforms with similar "triconodont-like" teeth for insectivory within the same fauna suggests a great trophic diversity within the mammaliaform insectivore feeding guild, as inferred from the range of body sizes.

Authors+Show Affiliations

Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, PA 15213, USA. luoz@carnegiemuseums.orgNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

11375489

Citation

Luo, Z X., et al. "A New Mammaliaform From the Early Jurassic and Evolution of Mammalian Characteristics." Science (New York, N.Y.), vol. 292, no. 5521, 2001, pp. 1535-40.
Luo ZX, Crompton AW, Sun AL. A new mammaliaform from the early Jurassic and evolution of mammalian characteristics. Science. 2001;292(5521):1535-40.
Luo, Z. X., Crompton, A. W., & Sun, A. L. (2001). A new mammaliaform from the early Jurassic and evolution of mammalian characteristics. Science (New York, N.Y.), 292(5521), 1535-40.
Luo ZX, Crompton AW, Sun AL. A New Mammaliaform From the Early Jurassic and Evolution of Mammalian Characteristics. Science. 2001 May 25;292(5521):1535-40. PubMed PMID: 11375489.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A new mammaliaform from the early Jurassic and evolution of mammalian characteristics. AU - Luo,Z X, AU - Crompton,A W, AU - Sun,A L, PY - 2001/5/26/pubmed PY - 2001/6/8/medline PY - 2001/5/26/entrez SP - 1535 EP - 40 JF - Science (New York, N.Y.) JO - Science VL - 292 IS - 5521 N2 - A fossil from the Early Jurassic (Sinemurian, approximately 195 million years ago) represents a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts. It has an enlarged cranial cavity, but no postdentary trough on the mandible, indicating separation of the middle ear bones from the mandible. This extends the earliest record of these crucial mammalian features by some 45 million years and suggests that separation of the middle ear bones from the mandible and the expanded brain vault could be correlated. It shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups. With an estimated body weight of only 2 grams, its coexistence with other larger mammaliaforms with similar "triconodont-like" teeth for insectivory within the same fauna suggests a great trophic diversity within the mammaliaform insectivore feeding guild, as inferred from the range of body sizes. SN - 0036-8075 UR - https://www.unboundmedicine.com/medline/citation/11375489/A_new_mammaliaform_from_the_early_Jurassic_and_evolution_of_mammalian_characteristics_ L2 - http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=11375489 DB - PRIME DP - Unbound Medicine ER -