Василиса▶ Я жду вашего обращения. Что Вы хотите узнать?
Логотип
Epipubic bones in eutherian mammals from the late Cretaceous of Mongolia. - PubMed - NCBI
Format

Choose Destination
1997 Oct 2;389(6650):483-6.

Epipubic bones in eutherian mammals from the late Cretaceous of Mongolia.

1
Department of Vertebrate Paleontology, American Museum of Natural History, New York, New York 10024, USA. novacek@amnh.org

Abstract

An important transformation in the evolution of mammals was the loss of the epipubic bones. These are elements projecting anteriorly from the pelvic girdle into the abdominal region in a variety of Mesozoic mammals, related tritylodonts, marsupials and monotremes but not in living eutherian (placental) mammals. Here we describe a new eutherian from the Late Cretaceous period of Mongolia, and report the first record of epipubic bones in two distinct eutherian lineages. The presence of epipubic bones and other primitive features suggests that these groups occupy a basal position in the Eutheria. It has been argued that the epipubic bones support the pouch in living mammals, but epipubic bones have since been related to locomotion and suspension of the litter mass of several attached, lactating offspring. The loss of the epipubic bones in eutherians can be related to the evolution of prolonged gestation, which would not require prolonged external attachment of altricial young. Thus the occurrence of epipubic bones in two Cretaceous eutherians suggests that the dramatic modifications connected with typical placental reproduction may have been later events in the evolution of the Eutheria.

PMID:
9333234
DOI:
10.1038/39020
[Indexed for MEDLINE]

Publication types

MeSH terms

Supplemental Content

Full text links

Icon for Nature Publishing Group
Support Center
© 2014-2020 ЯВИКС - все права защищены.
Наши контакты/Карта ссылок