Chilga (Oligocene of Ethiopia)

Where: Ethiopia (12.6° N, 37.1° E: paleocoordinates 10.1° N, 34.2° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Chattian (28.1 - 23.0 Ma)

• "Sedimentary rocks total at least 130 m [with vertebrate localities spanning about 55 m in the composite section] and are exposed in a series of stream and gully cuts" that "comformably overlie the uppermost Ethiopian plateau flood basalts. A basalt sample from the base of the section... provides a whole-rock K-Ar date of 32.4 +/- 1.5 Myr... Duplicate 40Ar-39Ar analyses of K-feldspar from a tuff within the fossiliferous portion of the sedimentary section yield ages with a weighted average of 27.36 +/- 0.11 Myr... These data, along with the results from palaeomagnetic studies, support a correlation of the Chilga section with Chron C9n [i.e., Chattian]"

• member-level stratigraphic resolution

Environment/lithology: fluvial; lignite and siltstone

• "channel and floodplain deposits"
• "reworked volcaniclastics, common but usually thin lignites, and claystones and siltstones that often represent palaeosols with varying degrees of maturity": illustrated section includes only tuff, lignite, and siltstone and indicates that tuffs are rare and vertebrates mostly or entirely derive from siltstones

Size class: macrofossils

Primary reference: J. Kappelman, D. T. Rasmussen, W. J. Sanders, M. Feseha, T. Bown, P. Copeland, J. Crabaugh, J. Fleagle, M. Glantz, A. Gordon, B. Jacobs, M. Maga, K. Muldoon, A. Pan, L. Pyne, B. Richmond, T. Ryan, E. R. Seiffert, S. Sen, L. Todd, M. C. Wiemann and A. Winkler. 2003. Oligocene mammals from Ethiopia and faunal exchange between Afro-Arabia and Eurasia. Nature 426:549-552 [J. Alroy/J. Alroy]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 71941: authorized by John Alroy, entered by John Alroy on 17.05.2007, edited by Pauline Coster and Mark Uhen

Creative Commons license: CC BY (attribution)

Taxonomic list

• "vertebrates, invertebrates, plant macrofossils and trace fossils" were collected, but only mammals are listed
 Proboscidea - Palaeomastodontidae
Phiomia major n. sp.2 Sanders et al. 2004 proboscidean
said to be new
aff. Palaeomastodon "sp. nov. B" Andrews 1901 proboscidean
aff. Palaeomastodon "sp. nov. A" Andrews 1901 proboscidean
 Proboscidea - Gomphotheriidae
cf. Gomphotherium sp. Burmeister 1837 gomphothere
said to be new
 Proboscidea - Deinotheriidae
Chilgatherium harrisi n. gen. n. sp.2
Chilgatherium harrisi n. gen. n. sp.2 Sanders et al. 2004 deinothere
said to be new
 Embrithopoda -
Arsinoitherium giganteum n. sp.2 Sanders et al. 2004 placental
said to be new
 Hyracoidea - Pliohyracidae
Bunohyrax sp. Schlosser 1910 hyrax
Megalohyrax sp. Andrews 1903 hyrax
said to be new
Pachyhyrax sp. Schlosser 1910 hyrax
said to be new
aff. Pachyhyrax sp. Schlosser 1910 hyrax
said to be new
 Hyaenodonta - Hyainailouridae
Hyainailouros sp.1 Stehlin 1907 eutherian