Life underground in the North American Miocene
- 出版日期：2004.
- 页数：1 v. :
- 第一责任说明：Katrina Elizabeth Gobetz.
- 分类号：a565
- ISBN：049613678X(ebk.) :
MARC全文
02h0029505 20120619145227.0 cr un||||||||| 120619s2004 xx ||||f|||d||||||||eng | 3153183 049613678X(ebk.) : CNY371.35 NGL NGL NGL a565 Gobetz, Katrina Elizabeth. Life underground in the North American Miocene [electronic resource] : interpretive analysis of mammalian burrows / Katrina Elizabeth Gobetz. 2004. 1 v. : digital, PDF file. Adviser: Martin, Larry D. Thesis (Ph.D.)--The University of Kansas, 2004. This study aims to broaden the scope of ichnology by incorporating the analysis of mammalian burrows. I use information on modern subterranean habitats, the vertebrates inhabiting them, their digging strategies, and their burrows to interpret burrow morphology and vertebrate ethology in the fossil record. Casts of the tunnels of modern North American moles (Scalopus aquaticus ) demonstrate how the burrow of an organism reflects body size, body shape, and digging movements. Forelimb morphology and digging motions of moles compare with traces on the tunnel casts, providing an interpretive model for burrows of extinct mammals. Vertebrate burrows occur abundantly in paleosols in the Harrison Formation of the Nebraska Miocene, a unit of aeolian sandstone rich in volcanic glass. Daemonelix burrows of the smallest palaeocastorin beaver, Pseudopalaeocastor barbouri, are described, in relation to previously described burrows of larger species. Small (c. 6 cm diameter), sinuous burrows showing rodent incisor marks and claw marks occur within the same beds and are attributed to Gregorymys sp., a gopher-like rodent. The abrasive texture of the glass-rich sand may have necessitated incisor-digging. Extensive, anastomosing back-filled traces (8 cm diameter) occur in the root horizon among abundant insect burrows, and may indicate foraging of an insectivorous vertebrate. The late Miocene Pawnee Creek Formation of northeastern Colorado contains burrows of c. 11 cm diameter, which are similar to modern subterranean rodent burrows and are covered with claw marks. Morphology of claw marks matches foreclaws of the mylaglaulid rodent P. laevis. Mylagaulids originally were reconstructed with medially facing mani and "terrier-style" digging motions. Re-examination of P. laevis shows that mylagaulids had semi-sprawling stance, and could rotate the forelimb for postero-laterally directed power strokes. The burrows in the Pawnee Creek Formation may thus be the first record of mylagaulid digging ethology. Mylagaulids also may have been head-lift diggers, as implied by paired bosses on the nasals as a possible adaptation to resist force against the rostrum, and may be the primitive condition for later-evolving paired horns. Mammalian ichnofossils such as these enable better understanding of subterranean biodiversity on the Miocene plains, and provide a reference for future studies in vertebrate ichnology. Mammals, Fossil. Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=Vdw%2fEmfFMOA%3d NGL Bs1561 rCNY371.35 ; h1 bs1204