Myzopoda africana, Gunnell & Butler & Greenwood & Simmons, 2015

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 : 3-7

† Myzopoda africana , new species

Figures 2 , 3

Myzopoda sp., Butler, 1978: 65; Gunnell, 2010: 586.

HOLOTYPE: NMT.010/Bat, complete left humerus (see table 1 for measurements).

ETYMOLOGY: The species name is given for the African continent, since the new species represents the only known occurrence of the genus Myzopoda on continental Africa; extant species are restricted to Madagascar.

TYPE LOCALITY: Tanzania: Arusha Province, Olduvai Gorge, Bed I, FLK NI, Layer 123.

DIAGNOSIS: Differs from living Myzopoda schliemanni and M. aurita in having a larger humerus (mean dimensions 21% larger) that is more robust and has a relatively longer deltopectoral crest, a more rounded humeral head, a more robust lesser tubercle, a more distinct and elongate lateral capitular tail, a more distinct and laterally compressed capitulum, and a relatively broader epitrochlea with a more distally extended epitrochlear process.

REFERRED SPECIMENS: NMT.008/Bat, left proximal humerus from Olduvai Bed I, FLK NI, layer 123; NMT.009/Bat, right distal humerus, Olduvai Bed 1, FLK NI, layer 4 (collected 1960).

DESCRIPTION: Three humeri from Olduvai can be assigned to Myzopoda based on the presence of the following combination of characters: round, bulbous capitulum, extended capitular tail with flaring lip, a broad epicondyle with two distinct processes, and a humeral head placed distal to the trochiter (greater tubercle). The proximal humerus (fig. 2) of M. africana has a semi-rounded, distolaterally slightly flattened head. The proximal extent of the head does not extend as far proximally as the trochiter and is even slightly below the proximal extent of the lesser tubercle. The deltopectoral crest is elevated anteriorly, is relatively long and curving, and has a sharply defined anterior margin with a slight overhanging lip developed medially. Distally (figs. 2, 3), the humerus of M. africana has a rounded and slightly laterally compressed capitulum that is robust and not offset from the long axis of the humeral shaft. The lateral capitular tail is as broad as the trochlear surface. The trochlear groove is distinct but not deeply invaginated and with a sharply defined trochlear lip. The medial epicondyle is robust with a relatively elongate process that extends distally beyond the trochlear ridge and is developed as two rounded surfaces aligned anteroposteriorly. There is a small but distinct groove on the lateral surface of the epicondyle.

Other fossil material of Myzopoda is unknown from both Africa and Madagascar, although more ancient myzopodids referred to another genus have been described from Egypt ( Gunnell et al., 2014).

Figures

FIGURE 2. A, C, Left humerus of Myzopoda africana, n. sp. (NMT.010/Bat, holotype) compared with B, D., Myzopoda schliemanni (FMNH 187668), in anterior (A–B) and posterior (C–D) views.

FIGURE 3. Left distal humerus of Myzopoda aurita (NHMUK.1849.11.3.5) compared with Myzopoda africana, n. sp. (NMT.010/Bat, holotype), in A, anterior, B, posterior, C, medial and D, lateral views.