Cardioderma leakeyi, 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 : 7-10

† Cardioderma leakeyi , new species

Figures 4 , 5

Megadermidae Butler and Greenwood, 1965: 14.

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

HOLOTYPE: NMT.003/Bat, left maxilla with P4–M3 (fig. 4), from the 1960 Olduvai Collection (see table 2 for measurements).

REFERRED SPECIMEN: NMT.002/Bat, right dentary with m1–3, FLK NI, Layer 3.

ETYMOLOGY: Named in honor of L.S.B. Leakey who was instrumental in initiating and leading the search for vertebrate fossils, especially fossil humans, in East Africa.

TYPE LOCALITY: Tanzania: Olduvai Gorge, Bed I, FLK NI, Layer 2.

DIAGNOSIS: Differs from extant Cardioderma cor in averaging 18%–20% larger in tooth dimensions; P4 with relatively larger parastyle and metastyle and better developed labial cingulum; M1–2 with relatively more robust mesostyle, deeper parafossa and metafossa, and deeper trigon basin; less reduced M3/m3; m1 and m2 with relatively broader talonid basin and more robust metaconid; m3 with broader trigonid and less reduced talonid.

DESCRIPTION AND COMPARISONS: The specimens referred to Cardioderma leakeyi can be recognized as megadermatids based on the robust nature of the cusps and crests on upper and lower cheek teeth, the large hypocone shelves and the narrow and labiolingually restricted protofossae on M1–2, the broadly open trigonid on m1 and the high and short lower molar talonids. The holotype maxilla (NMT.003/Bat, fig. 4) has a maxillary foramen that opens over the anterior root of P4 as in the extant species of Cardioderma , C. cor . There is a secondary and smaller foramen that opens more ventrally on the maxilla over the posterior root of P4 (this foramen is slightly more posteriorly placed in the extant species). In lateral view, the anterior labial root of M1 is exposed through the bony surface of the maxilla, as is often the case in C. cor . The root of the zygomatic arch is dorsal to M2 as in the living form, but it is much more robust in C. leakeyi , as is the anterior orbital process. The optical foramen is the same size and in the same position in both species of Cardioderma .

The P4 of Cardioderma leakeyi has a robust paracone, relatively large parastyle and metastyle, and a relatively heavy labial cingulum. The lingual cingulum is relatively broad anteroposteriorly and extends lingually farther than is seen in C. cor . M1–2 each have a prominent hypocone shelf, an anteroposteriorly narrow but labiolingually extended and deep protofossa, a robust mesostyle, and parastylar and metastylar foveae that are nearly equivalent in size (whereas in C. cor the metastylar fovea is typically larger). M3 has a relatively robust parastyle and a labiolingually short lingual shelf and is less anteroposteriorly compressed than seen in C. cor .

The horizontal ramus of the dentary (NMT.002/Bat) is relatively deep in Cardioderma leakeyi (3.0 mm beneath m1) compared to C. cor (2.0 mm below m1). The lower molars of C. leakeyi (fig. 5) are all quite similar to those of extant C. cor . The m1 is broken anteriorly, making it impossible to tell whether C. leakeyi had a small, low, and centered paraconid as seen in C. cor . All three lower molars of C. leakeyi have a prominent protoconid and a somewhat lower, but distinct, metaconid. Lower m2 and m3 have distinct paraconids that are placed somewhat lower than the metaconids. The hypoflexid is deep and the cristid obliqua is angled and joins the postvallid of the trigonid well lingual of center on all molar teeth. The hypoconid on m1–2 is distinct, but it is less so on m3; the entoconid is distinct only on m1. Molar talonids are broader than those seen in C. cor , but the talonid is not as broad as the trigonid on any tooth. All molars have moderate and complete labial cingulids.

The only other published record of a fossil Cardioderma species ( Louchart et al., 2009) is from the early Pliocene in Ethiopia. However, the material upon which that assignment is based has never been described or figured making comparisons impossible at this time.

Figures

FIGURE 4. Upper dentition of Cardioderma cor (A) compared with Cardioderma leakeyi, n. sp. (B–D). A, AMNH 184338, palate (photograph). NMT.003/Bat (holotype) left maxilla with P4–M3 in B, C lateral (drawing and photograph of cast, respectively) and D occlusal (drawing) views.

FIGURE 5. Lower dentition of Cardioderma cor (A–B) compared with Cardioderma leakeyi, n. sp. (C). A, AMNH 184338, photograph of right m1–3; B, NHMUK 36.11.4.4, drawing of right m1–3; C, NMT.002/Bat, right m1–3 (drawing on left, photograph of cast on right).