Macroderma handae, Armstrong & Aplin & Motokawa, 2020

Armstrong, Kyle N., Aplin, Ken & Motokawa, Masaharu, 2020, A New Species of Extinct False Vampire Bat (Megadermatidae: Macroderma) from the Kimberley Region of Western Australia, Records of the Australian Museum (Rec. Aust. Mus.) 72 (5), pp. 161-174 : 163-172

publication ID	https://doi.org/ 10.3853/j.2201-4349.72.2020.1732
publication LSID	lsid:zoobank.org:pub:D252FDFE-7C93-4E13-8DC7-FFB585ACC16F
persistent identifier	https://treatment.plazi.org/id/018A744D-3AE6-44C0-988E-018C963EEE8E
taxon LSID	lsid:zoobank.org:act:018A744D-3AE6-44C0-988E-018C963EEE8E
treatment provided by	Felipe
scientific name	Macroderma handae
status	sp. nov.

Treatment

Macroderma handae sp. nov. Aplin and Armstrong urn:lsid:zoobank.org:act:018A744D-3AE6-44C0-988E-018C963EEE8E

Figs 3–8 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 View Figure 8

Holotype. Fragment of left dentary containing a mostly intact M 2, broken P 4, M 1 and M 3, and alveoli of single-rooted P 2 and C 1 ( WAM 2020.4.1; Figs 3A,B View Figure 3 and 4A,C,E,G View Figure 4 ) . Paratypes.A second fragment of left dentary with alveoli of incisors, C 1, P 2 and P 4, and first two molars ( WAM 2020.4.2; Fig. 3D,E View Figure 3 ); a third fragment of left dentary containing a worn M 1 and one alveolus of M 2 ( WAM 2020.4.3; Fig. 3C View Figure 3 ); palatal fragment of left maxilla with lingual alveoli of P 4 and M 1 ( WAM 2020.4.4; Fig. 5B,C View Figure 5 ); fragment of right maxilla with alveoli of C 1 and P 4 ( WAM 2020.4.5; Fig. 5A View Figure 5 ); right M 1 ( WAM 2020.4.6; Fig. 6A,C View Figure 6 ); right M 2 fragment ( WAM 2020.4.10; Fig. 6E View Figure 6 ); anterior portion of right C 1 ( WAM 2020.4.7; Fig. 7A View Figure 7 ); right C 1 with broken paracone (principal cusp, sensu Hand, 1985; WAM 2020.4.9; Fig. 7C,D View Figure 7 ); left P 2 ( WAM 2020.4.8; Fig. 8A,B,D View Figure 8 ); left M 3 in poor condition ( WAM 2020.4.11; Fig. 4I View Figure 4 ); left P 4 with damaged paracone (principal cusp; WAM 2020.4.12; Fig. 8E–H View Figure 8 ). All type material is lodged in the Western Australian Museum .

Type locality, lithology, and age. Material was collected from a cemented accumulation of bone material that formed on the floor of a cave in a carbonate-rich stratigraphic sequence at Dingo Gap, Oscar Range , Kimberley region , Western Australia (17°40'S 125°13'E, Fig. 1 View Figure 1 ). The location is part of the marginal reef slope and basinal facies of the northern face of the Oscar Range (Stephens & Sumner, 2003). This range forms the northern edge of the Canning Basin, and is the remnant of an Upper Devonian marine reef complex GoogleMaps .

The bone accumulation was in a hard limestone matrix and consisted of teeth and small bone fragments of mammals, particularly rodents ( Muridae : Hydromyini (sensu Smissen & Rowe, 2018); Rattus was absent). Further details of the fauna in this collection are not yet available. It is more likely to be an accumulation from a cave floor beneath a megadermatid bat roost site rather than a pellet accumulation from an owl given that larger jaw fragments were absent. Dental material from other bats was also present, including an unknown species of bat ( Fig. 9A–D View Figure 9 ), canines from an emballonurid (probably Taphozous sp. ; Fig. 9E–L View Figure 9 ), and a lower row of molars from an unidentified vespertilionid ( Fig. 9M,N View Figure 9 ). Given the absence of Rattus , which is thought to have reached Australia by at least the mid-Pleistocene (Rowe et al., 2019), the material is aged tentatively as Pliocene or early Pleistocene.

Diagnosis. Referred to the genus Macroderma Miller, 1906 on the basis of the large size of the M 1–2 (within the lower part of the size range of M. gigas and M. koppa ; Table 1; cf. Hand, 1995: 52), the M 1 with elongated heel, and markedly lingually displaced mesostyle (cf. Megaderma richardsi ; Hand, 1995: 66); M 1–3 paracristid (sensu Hand, 1995, 1996; = protocristid sensu Hand, 1985, who used both terms) longer than metacristid; M 1–3 reduced metaconid contribution to the cristid obliqua; M 1–3 robust and continuous anterior, labial (= buccal) and posterior cingula (see Hand, 1996: 373).

Compared with Macroderma gigas —Maxilla fenestrated ( Fig. 5B,C View Figure 5 ), but not to the degree seen in M. gigas (cf. Hand, 1985: 31); anterior part of dentary thickened, though relatively gracile compared with that of M. gigas (dentary depth below M 2 protoconid less in M. handae ; Table 1; Fig. 3A,F View Figure 3 ); most molar measurements smaller than the average for M. gigas , or within the lower part of the size range ( Table 1); the shape of the M 1 protofossa (whose edges are defined by the preprotocrista and postprotocrista) is rounded rather than triangular ( Fig. 6A–D View Figure 6 ); M 2 paraconid lower, and protruding less anteriorly past the protoconid (trigonid less expanded anteriorly than in M. gigas ); M 2 protoconid relatively high and of proportionally greater area within the trigonid (more than half in occlusal view ( Fig. 4A,B View Figure 4 ); and M 2 talonid proportionally larger with respect to the trigonid ( Fig. 4A,B View Figure 4 ). No protostyle cusp on P 4, which is obvious in M. gigas ( Fig. 8E,F View Figure 8 ).

Compared with M. koppa (see Hand et al., 1988: 344–346)—Anterior upper tooth row relatively shorter in M. handae , alveoli of C 1 and P 4 indicating overlap of crowns ( Fig. 5A View Figure 5 ; cf. Hand et al., 1988: 345, fig. 2b,c); the shape of the M 1 protofossa (with edges defined by the preprotocrista and postprotocrista) is rounded rather than triangular; molar measurements smaller than the values for M. koppa ( Table 1; cf. Hand et al., 1988: 349); anterior part of dentary relatively gracile compared with that of M. koppa (dentary depth below M 2 protoconid less in M. handae ; Table 1); M 2 paraconid relatively low, and protruding less anteriorly past the protoconid due to anterior compression of the trigonid ( Fig. 4C,E View Figure 4 ; cf. Hand et al., 1988: 345, fig. 2a); M 2 protoconid relatively high and of proportionally greater area within the trigonid (more than half in occlusal view; Fig. 4A View Figure 4 ); entoconid smaller than hypoconulid ( Fig. 4E,G View Figure 4 ; cf. Hand et al., 1988: 345, fig. 2a); the P 2 is of a similar shape in both species ( Fig. 8A,B,D View Figure 8 ; cf. Hand et al., 1988: 345, fig. 2a).

Compared with M. malugara Hand, 1996 —P 2 absent in M. handae ; slightly smaller size of M 1 and M 2 ( Table 1; cf. Hand, 1996: 368); the shape of the M 1 protofossa (whose edges are defined by the preprotocrista and postprotocrista) is rounded rather than triangular; M 2 paraconid relatively low, and protruding less anteriorly past the protoconid due to anterior compression of the trigonid ( Fig. 4A,C,E View Figure 4 ; cf. Hand, 1996: 366–367, pl. 48k–m); M 2 protoconid relatively high and of proportionally greater area of the trigonid (more than half in occlusal view; Fig. 4A View Figure 4 ; cf. Hand, 1996: 366–367, pl. 48m); greater development of M 2 hypoconulid ( Fig. 4A View Figure 4 ; cf. Hand, 1996: 366–367, pl. 48m).

Compared with M. godthelpi Hand, 1985 —C 1 and M 1 and M 2 slightly larger in size in M. handae , and M 2 with greater protoconid height ( Table 1; cf. measurements in Hand, 1985: 8–9; see also Sigé et al., 1982 for measurement key); taller and more robust C 1 ( Table 1 E; Fig. 7A,C,D View Figure 7 ; cf. Hand, 1985: 9,12, fig. 5a,b); loss of P 2; proportionally greater contribution of the cingulum to the height of the P 2 (cf. Hand, 1985: 13, fig. 6c); M 2 paraconid relatively low, and protruding less anteriorly past the protoconid due to anterior compression of the trigonid ( Fig. 4A,C,E View Figure 4 ; cf. Hand, 1985: 11, fig. 4a,b,c); M 2 protoconid relatively high and of proportionally greater area of the trigonid (more than half in occlusal view; Fig. 4A View Figure 4 ; cf. Hand, 1985: 11, fig. 4c).

Description. The anterior part of the dentary is thickened, though relatively gracile and shallower in depth compared to M. koppa and M. gigas , with likely two lower incisors per side (paratype WAM 2020.4.2; anterior detail not shown in Fig. 3A,B,D,E View Figure 3 ). Two premolars are present—P 2 and P 4, in addition to the M 1–2 ( Fig. 3A,B View Figure 3 ), and the M 3 ( Fig. 4I View Figure 4 ).

There is marked extension posterolingually of the C 1, similar to M. gigas ( Fig. 7A–D View Figure 7 ). The P 2 has a proportionally large cingulum, as can be seen in occlusal view, which gives the tooth the appearance of a “witches hat” when viewed from either the labial or lingual side ( Fig. 8A,B,D View Figure 8 ).

The M 1 is shorter than, or equal in length to, the tall-crowned M 2 ( Fig. 3A View Figure 3 ). The paracristid of the M 2 is longer than the metacristid ( Fig. 4A View Figure 4 ). There is relatively little contribution of the M 2 metaconid to the cristid obliqua ( Fig. 4A View Figure 4 ). The M 2 hypoconulid is situated posteriorly ( Fig. 4A View Figure 4 ). The anterior, labial, and posterior cingula are robust and continuous ( Fig. 4A,E,G View Figure 4 ). There is no development of the entostylid ( Fig. 4A View Figure 4 ).

The maxilla is rugose and fenestrated, with grooves of blood vessels along the surface ( Fig. 5B,C View Figure 5 ). The condition of the infraorbital foramen (a key feature separating M. koppa [two foramina] and M. gigas [one foramen]; Fig. 5A View Figure 5 ) cannot be observed.

The P 2 is absent, as indicated by the absence of an alveolus between those of the canine and P 4 (paratype WAM 2020.4.5; Fig. 5A View Figure 5 ). The alveolus of C 1 and anterobuccal/ anterolabial alveolus of P 4 indicate that the crowns of these teeth overlapped in the tooth row ( Fig. 5A View Figure 5 ). The heel of the P 4 is broad, and the posterior edge is at right angles to the paracone (it is angled close to 45° lingually in M. gigas ; Fig. 8E–H View Figure 8 ). There is no protostyle cusp, which is obvious in M. gigas ( Fig. 8E,F View Figure 8 ).

The M 1 has a broad labial (buccal, sensu Hand, 1996) shelf, though narrower than that of M. gigas ( Fig. 6A,B View Figure 6 ), and a markedly lingually displaced mesostyle (cf. Megaderma richardsi ; Hand, 1995). The preprotocrista and postprotocrista are curved, giving the protofossa a rounded shape, which contrasts with the more triangular form of other Macroderma species ( Hand et al., 1988: 345, fig. 2c; Hand, 1985: 10, fig. 3c, 1996: 366–367, pl. 48d), and also Megaderma richardsi ( Hand, 1995: pl. 1b,c). Both the M 1 and M 2 have tall crowns, and appear to be slightly compressed anteroposteriorly relative to Macroderma gigas ( Fig. 6A–F View Figure 6 ).

Unidirectional wear striations are observable on the left M 3, which resemble those found on the teeth of the predatory M. gigas that crush the bones of prey ( Fig. 5D,E View Figure 5 ).

Etymology. Named in honour of Professor Suzanne (“Sue”) J. Hand of the University of New South Wales, in recognition of her previous extensive work on fossils of this family, and her extraordinary, sustained, and ongoing work on fossils that has helped piece together the rich history of the Australasian mammal fauna.