Myotis

Gunnell, Gregg F., Butler, Percy M., Greenwood, Marjorie & Simmons, Nancy B., 2015, Bats (Chiroptera) from Olduvai Gorge, Early Pleistocene, Bed I (Tanzania), American Museum Novitates 2015 (3846), pp. 1-35 : 15

Cf. Myotis sp.

Myotis sp., Butler, 1978: 65; Gunnell, 2010: 588.

REFERRED SPECIMEN: NMT.012/Bat, left damaged distal humerus, FLK NI, layer 3 (see table 1 for measurements).

DESCRIPTION AND DISCUSSION: NMT.012/Bat is the only specimen in the Olduvai sample that may represent Myotis . The distal end of the humerus of NMT.012/Bat has typical Myotis features including having a relatively narrow capitulum that is not offset from shaft, a lateral capitular tail that is less broad than trochlear surface and proximolaterally extended into a distinct lip, a trochlear groove that is essentially absent, and a trochlear surface that is relatively broad with a trochlear lip that is not sharply defined. Additionally, the medial epicondyle has a small process that does not extend distally beyond the trochlear ridge and the groove on the posterolateral surface of the epicondyle is deep, narrow, and distinct.

Of the 12 Myotis species living in Africa today ( Simmons, 2005), only M. dieteri ( Democratic Republic of Congo), M. morrisi ( Ethiopia, Nigeria), M. scotti ( Ethiopia) , M. tricolor (subSaharan Africa), M. bocagii (western and southern Africa), and M. welwitschii (sub-Saharan Africa) are found south of the Sahara, and of these only M. welwitschii lives in Tanzania today. NMT.012/Bat represents a relatively large species of Myotis , such as M. welwitschii , and may well be related to, or even represent, that species.

Myotis is poorly represented in the fossil record of Africa in the Plio-Pleistocene and is restricted to southern Africa ( Broom, 1948; Pocock, 1987) outside of the record from Tanzania and an occurrence in Morocco ( Gunnell et al., 2011). Myotis is a common element of other Plio-Pleistocene faunal communities and is widespread across the northern continents during this time period (Simmons and Gunnell, in prep.).