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Monadjem, Ara, Shapiro, Julie T., Richards, Leigh R., Karabulut, Hatice, Crawley, Wing, Nielsen, Ida Broman, Hansen, Anders, Bohmann, Kristine, Mourier, Tobias (2019): Systematics of West African Miniopterus with the description of a new species. Acta Chiropterologica 21 (2): 237-256, DOI: 10.3161/15081109ACC2019.21.2.001

Miniopterus nimbae sp. nov. Nimba long-fingered bat Holotype DM 12621 (field no. AM2010_12_18_1), an adult male, was collected by Ara Monadjem. The specimen was fixed in formalin and then transferred to 70% alcohol. The skull has been extracted and cleaned. Photograph of the skull and drawing of the tragus of the holotype are illustrated in Figs. 6 and 7. Type locality Liberia, Nimba Province, Mount Gangra, 10 km to the west of Mount Nimba (Fig. 1). The bat was netted on 18 December 2010 exiting from a mine adit mid-way up Mount Gangra (7.55434°N, 8.62902°W) at 720 m a.s.l, in secondary forest. Paratypes No other specimens of this species were captured or collected on the same day at the same site. However, the previous night an adult female (DM 12614) was collected at the Yiti River 9 km to the south-east of Mount Gangra. Photograph of the paratype is illustrated in Fig. 8. Etymology This species is named after Mount Nimba, one of just three localities from which it is known, further highlighting the critical importance of this mountain for bat conservation in Africa (Monadjem et al., 2016). Diagnosis This is a large-sized Miniopterus from Mount Nimba, Liberia, with a mean forearm length of 47.4 mm (n = 26 individuals). The large size of this bat (particularly its forearm length) readily distinguishes M. nimbae from all other African Miniopterus taxa except the M. inflatus / M. africanus group. In external and craniodental measurements, M. nimbae is similar in size to other members of the M. inflatus group (M. inflatus s.s., M. cf. inflatus and M. africanus) (Tables 3–5); however, in multi-dimensional morphospace based on craniodental measurements, it overlaps only with M. inflatus s.s. The taxon M. cf. inflatus from eastern and southern Africa tends to have a light pelage, being more reddish-brown in colour (compared with a deep chocolate brown in M. nimbae). It is not possible, at present to distinguish M. nimbae from M. inflatus s.s. on external characters. However, they can be readily distinguished by cranial features. In particular, the 1st upper premolar has an additional lingual cusp, posterior to the main cusp, that is present in M. nimbae but absent in M. inflatus s.s. (Fig. 9); this feature being clearly visible, even with a low magnification hand lens, and consistently present in all the specimens examined in this study. The lower tooth row (i 1 –m 3) and lower molar (LWMOLS) lengths are also slightly larger in M. nimbae than M. inflatus s.s. In terms of cranial geometry, M. nimbae differs from M. inflatus s.s. as it bears a slightly more gracile skull, less ‘inflated’ braincase, and the point of maximum curvature along the occiput is more elevated in the newly described taxon than in the nominate form. Furthermore, these two taxa, are also distinguishable on molecular grounds (K2P pairwise genetic distance = 1.6%). Additionally, the ranges of the two taxa do not appear to overlap. Miniopterus africanus appears to be restricted to north-eastern Africa and is genetically distinct (K2P pairwise distance = 16.7%) from M. nimbae. Description External characters.— Miniopterus nimbae is large-sized for the genus, but showing typical generic features including a rounded head, an elongated second phalanx of the third digit, rounded ears, and a relatively long and straight tragus. The tail is slightly less than half that of the total length. The pelage is dark chocolate brown above and slightly paler below. Individual hairs are unicoloured. The mass and standard external measurements of the holotype compared with a small sample of other individuals are shown in Table 3. Craniodental characters.—The skull is robust for a Miniopterus species. The rostrum is broad and the braincase is rounded and high, typical for the genus of Miniopterus. The dentition of M. nimbae is I 2/3, C 1/1, P 2/3, M 3/3, which is typical of the genus. In the upper tooth row, the inner incisor is larger than the outer one, and the anterior premolar is relatively well developed. The cranial and dental measurements of the holotype compared with a small sample of other individuals are shown in Tables 4 and 5. Distribution Analysis of genetic samples taken from five specimens with large forearm lengths (range 46.9– 48.2 mm) at Mount Gangra (Nimba, Liberia), group them all as M. nimbae (Figs. 2 and 3). Although not genetically analysed, it is likely that specimens previously collected from northern Liberia or southeastern Guinea and identified as M. inflatus are instead referable to this new species, M. nimbae. Based on this assumption, this taxon is known from just three localities: Mount Nimba (and surrounding uplands), Liberia; Wonegizi Mountains, Liberia; and Mount Béro, Guinea (Wolton et al., 1982; Koopman et al., 1995; Fahr et al., 2006; Monadjem et al., 2016). The closest locality for M. inflatus s.s. is at least 2,000 km away in eastern Nigeria (Happold, 2013 b), and no other large Miniopterus specimens have been collected in the intermediate area, despite extensive surveys in a number of localities e.g., Thaï and Comoé National Parks in Côte d’Ivoire (Fahr and Kalko, 2011), the Simandou Range in eastern Guinea (Decher et al., 2015), the Fouta Djallon mountains in central Guinea (Weber and Fahr, 2007) or anywhere in Ghana or Sierra Leone (Grubb et al., 1998; Happold, 2013 b, 2013 c). Therefore, M. nimbae is probably an endemic to the upland areas of northern Liberia and south-eastern Guinea, and may be shown to also occur in the upland area of western Côte d’Ivoire at and around Mount Nimba. Biology: Practically nothing is known about the biology of this Upper Guinea forest endemic. It has been recorded roosting in mine adits at 720– 970 m above sea level (a.s.l.) at Mount Gangra and Mount Yuelliton (both within 10 km of Mount Nimba). The size of one roosting colony at Mount Gangra was estimated at between 20–30 individuals; the site was shared with large numbers of Myonycteris angolensis and Hipposideros cf. ruber, and a few H. marisae. A second roosting colony was estimated to include> 200 individuals of this species at Mount Yuelliton (which was not inhabited by any other bat species — A. Monadjem, personal observation). It has been netted at various localities in the foothills of Mount Nimba and in the low-lying rainforest region between these three upland areas. This suggests that this species roosts in upland areas (700 m a.s.l.), and then descends to forage in lower lying forested areas (about 500 m a.s.l.). In a sample of 13 females captured at Nimba between late December and end-March, five were pregnant. During the same period, three out of 10 males had scrotal testes. The mean frequency of the knee of handreleased M. nimbae captured at Mount Nimba was 48.4 kHz (range: 47.2–48.9 kHz, n = 4). Other Taxonomic Considerations In addition to the description of the new species, M. nimbae, the phylogeny presented here (Figs. 2 and 3) also identifies two other distinct taxa. The first is the taxon M. villiersi, which does not appear to be closely related to M. schreibersii s.s. and should therefore not be considered a subspecies of the latter mentioned taxon. In fact, M. villiersi is sister to M. nimbae (Figs. 2 and 3), from which it is readily distinguishable based on genetics and size (see Tables 2–5); the pairwise genetic distance between the two species is 9.0%, and there is no overlap between these two species in forearm length or any of the craniodental measurements presented here. The echolocation calls also differ, with the frequency of the knee of M. villiersi calls (based on hand-released individuals that were captured at Mount Nimba — x = 51.6 kHz, range 51.1–52.4 kHz, n = 5) being distinctly higher than that of M. nimbae (x = 48.4 kHz, range 47.2–48.9 kHz, n = 4) with no overlap between the two species. The second taxon refers to the M. inflatus group, which appears to be paraphyletic. Miniopterus inflatus s.s. (based on sequenced specimens from Gabon, and close to the type locality in southern Cameroon) is sister to the taxon M. nimbae and these two are sister to M. villiersi (Figs. 2 and 3). By contrast, the M. cf. inflatus specimens (from Malawi and Mozambique) are sister to M. fraterculus and M. minor. This suggests that the taxon M. inflatus s.l. comprises, in addition to the newly recognised M. nimbae, two distinct and not closely related taxa which we refer to as M. inflatus s.s. (from Gabon), and M. cf. inflatus (from Malawi and Mozambique)., Published as part of Monadjem, Ara, Shapiro, Julie T., Richards, Leigh R., Karabulut, Hatice, Crawley, Wing, Nielsen, Ida Broman, Hansen, Anders, Bohmann, Kristine & Mourier, Tobias, 2019, Systematics of West African Miniopterus with the description of a new species, pp. 237-256 in Acta Chiropterologica 21 (2) on pages 245-248, DOI: 10.3161/15081109ACC2019.21.2.001, http://zenodo.org/record/3944920, {"references":["MONADJEM, A., L. RICHARDS, and C. DENYS. 2016. An African bat hotspot: the exceptional importance of Mount Nimba for bat diversity. Acta Chiropterologica, 18: 359 - 375.","WOLTON, R. J., P. A. ARAK, H. C. J. GODFRAY, and R. P. WILSON. 1982. Ecological and behavioural studies of the Megachiroptera at Mount Nimba, Liberia, with notes on Microchiroptera. Mammalia, 18: 359 - 375.","KOOPMAN, K. F., C. P. KOFRON, and A. CHAPMAN. 1995. The bats of Liberia: systematics, ecology, and distribution. American Museum Novitates, 3148: 1 - 24.","FAHR, J., B. A. DJOSSA, and H. VIERHAUS. 2006. Rapid assessment of bats (Chiroptera) in Dere, Diecke and Mt. Bero classified forests, southeastern Guinea; including a review of the distribution of bats in Guinee Forestiere. Pp. 168 - 180, 245 - 247, in A rapid biological assessment of three classified forests in Southeastern Guinea (H. E. WRIGHT, J. MCCULLOUGH, L. E. ALONSO, and M. S. DIALLO, eds.). RAP Bulletin of Biological Assessment, 40: 1 - 248.","HAPPOLD, M. 2013 b. Miniopterus inflatus Greater long-fingered bat. Pp. 714 - 716, in The mammals of Africa. Volume IV: Hedgehogs, shrews and bats (M. HAPPOLD and D. C. HAP- POLD, eds.). Bloomsbury Publishing, London, 800 pp.","FAHR, J., and E. K. V. KALKO. 2011. Biome transitions as centres of diversity: habitat heterogeneity and diversity patterns of West African bat assemblages across spatial scales. Ecography, 34: 177 - 195.","DECHER, J., A. HOFFMANN, J. SCHAER, R. W. NORRIS, B. KADJO, J. ASTRIN, A. MONADJEM, and R. HUTTERER. 2015. Bat diversity in the Simandou Mountain Range of Guinea, with the description of a new white-winged vespertilionid. Acta Chiropterologica, 17: 255 - 282.","WEBER, N., and J. FAHR. 2007. Survey of endemic and globally threatened bat species in the Fouta Djallon Plateau for","GRUBB, P., T. S. JONES, A. G. DAVIES, E. EDBERG, E. D. STARIN, and J. E. HILL. 1998. Mammals of Ghana, Sierra Leone and The Gambia. Trendine Press, Cornwall, UK, 265 pp.","HAPPOLD, M. 2013 c. Miniopterus schreibersii Schreibers's long-fingered bat. Pp. 721 - 722, in The mammals of Africa. Volume IV: Hedgehogs, shrews and bats (M. HAPPOLD and D. C. D. HAPPOLD, eds.). Bloomsbury Publishing, London, 800 pp."]}