III-B and I, but not C-F, L-M, Q, W, and CC) figure two Cetorhinus teeth from California (most likely from the middle Miocene Barstovian
, Round Mountain Silt) under the genus Gyrace Jordan, 1923, a junior synonym of Galeocerdo Muller and Henle, 1837.
The fossil assemblages specifically indicate a Barstovian age, which ranges from 16.
Discussion--The two faunal assemblages at Feyereisen Gap were compared to the other Barstovian assemblages using similarity equations.
Calamagras weigeli was widespread temporally and geographically, previously being reported from the Chadronian NALMA (Late Eocene) of Canada, Arikareean NALMA (Early Miocene) of Wyoming, Hemingfordian NALMA (Early Miocene) of South Dakota, and Barstovian NALMA (Middle Miocene) of Texas (3).
Geringophis depressus was known previously from the Early Arikareean NALMA (Late Oligocene) of Nebraska and Wyoming, and the Late Arikareean to Late Barstovian NALMA (Early to Middle Miocene, respectively) of Nebraska (Holman, 3).
The first Emydoidea remains are known from two Miocene Late Barstovian
NALMA (about 12 Ma) fossil quarries in Cherry County, Nebraska.
The holotype, a nuchal bone UNSM 76200 from UNSM Locality Cr 114, Cherry County, Nebraska (Miocene:Late Barstovian
, see Holman 1995, Figure 1, 549) should remain the same.
It occurs from the Miocene to the Recent in North America and ranged into Saskatchewan, Canada in late Barstovian
times (Holman 1970), well northwest of its present range.
or from numerous other (unpublished) plesiomorphic xantusiids ranging in age from Barstovian
(middle Miocene) to early Irvingtonian (early Pleistocene; CJB, pers.
All sites are Barstovian
and the three most abundant categories of small mammals are the geomyoid, cricetid and heteromyid rodents.
herefore the oldest known Emydoidea (Miocene: Barstovian
) was kinetic as in modern Emydoidea blandingii, but to a lesser degree than occurs in Barstovian
box turtles, genus Terrapene (Holman and Corner 1985).
mutica, and the extinct Barstovian
species Trionyx (?