Rhinolophus gorongosae, GORONGOSAE, 2018

Taylor, Peter J., Macdonald, Angus, Goodman, Steven M., Kearney, Teresa, Cotterill, Fenton P. D., Stoffberg, Sam, Monadjem, Ara, Schoeman, M. Corrie, Guyton, Jennifer, Naskrecki, Pitor & Richards, Leigh R., 2018, Integrative taxonomy resolves three new cryptic species of small southern African horseshoe bats (Rhinolophus), Zoological Journal of the Linnean Society 184, pp. 1249-1276 : 1262-1265

RHINOLOPHUS GORONGOSAE SP. NOV.

LEAST HORSESHOE BAT

Holotype: Durban Natural Science Museum (DM) No. 14820 (field number JAG196 ), is an adult male, preserved in 70% ethyl alcohol, originally part of series of specimens collected by J. A. Guyton on 25 April 2015. The cranium and baculum has been extracted and examined for this study. The specimen has been included in both morphometric analyses.

Type locality: Bunga Inselberg, Gorongosa National Park, Sofala Province, Mozambique − 18.599° S, 34.343° E, 212 m.

Paratypes: Eight specimens collected 24–25 April 2015 ( DM 14815–14819 ), 2 May 2015 ( DM 14828 ), 5 November 2015 ( DM 14843 ) and 22 July 2015 ( DM 14865 ).

Referred specimens having molecular identification: DM 14815 ( JAG 188 ) a female specimen collected by J. A. Guyton from Mozambique, Sofala Province, Gorongosa National Park, Bunga Inselberg , - 18.599° S, 34.343° E, 212 m; DM 14843 ( JAG 228 ) a female specimen collected by J. A. Guyton from Mozambique, Sofala Province, Gorongosa National Park, - 18.694° S, 34.208° E, 308 m.

Referred specimens having only morphological identification: TMSA 49116 ( JAG 31 ), adult male, collected on 21 April 2013 by J. A. Guyton from Mozambique, Sofala Province, Gorongosa National Park, Cheringoma Plateau , Gorge Rim , Site 1, - 18.635° S, 34.808° E, 213 m. Incertae sedis: DM 14864 adult female collected by J. A. Guyton on 21 July 2015 from Mozambique, Sofala Province, Gorongosa National Park, - 18.465° S, 34.052° E, 1150 m ; DM 11482 , adult female collected on 1 May 2009 by J. Bayliss from Mozambique, Nampula Province, Mount Inago Forest Camp , - 15.045° S, 37.396° E 1478 m.

Etymology: The species derives its name from the Gorongosa district of Mozambique, in particular Gorongosa National Park, a biologically diverse region of southern Africa.

Diagnosis: The species can be clearly distinguished from both R. swinnyi s.s. and R. rhodesiae on molecular grounds ( Figs 2 , 3 ) as well as by its smaller size ( Fig. 4 ; Table 2 ), distinct cranial shape ( Figs 5 , 6 ), echolocation call peakfrequency ( Table 2 ), baculum ( Figs 7 , 8 ) and noseleaf ( Figs 9 , 12 ) characteristics. Although some measurements overlap, there is minimal overlap in condylocanine skull length and zygomatic skull width between this species (14.8–15.2 mm; 8.13–8.56 mm) and R. swinnyi (14.3–16.0 mm; 8.7–9.2 mm) and R. rhodesiae (15.1–15.7; 8.46–8.96 mm). The small size of this form makes it even smaller than denti (regarded by Csorba et al., 2003 as the smallest species in the Ethiopian region), therefore making this new species Africa’s smallest horseshoe bat. Comparing means for R. gorongosae sp. nov. ( Table 2 ) and denti ( Monadjem et al., 2010) : forearm 41.3 mm cf. 43.1 mm; mass 5.6 g cf. 7.0 g.

Description: The genetically-distinct R. gorongosae sp. nov. is similar in pelage colour but distinctly smaller in external (mean total length 68 mm, mean forearm length = 41 mm) and cranial (mean condylocanine length 15.1 mm) measurements ( Table 2 ) than both rhodesiae (mean totallength 75 mm, forearmlength 44 mm, condyolocanine length 15.4 mm) and swinnyi s.s. from South Africa (mean totallength 73 mm, forearm length 44 mm, condyolocanine length 15.4 mm). Based on geometric morphometric results, the diminutive R. gorongosae sp. nov. has a reduced foramen magnum, a noticeable depression along the parietal region, low set bullae, a narrow braincase and a narrow and high set nasal inflation with a sharp slope from the nasal inflation to the maxillae ( Fig. 6 ). Lancet is subtriangular with straight to slightly concave sides, and a high, rounded connecting process; the sella has a diminutive, pointed tip ( Fig. 12 ). Baculum short with reduced base, with a characteristic notch on one side of the shaft tip (position variable). The slightly narrower baculum shaft with narrower tip distinguishes R. gorongosae sp. nov. from R. swinnyi ( Table 5 ; Figs 7 , 8 ). Maxillary toothrow with minute and laterally displaced PM 1 with a distinct gap between the alveolar borders of canine and PM 2 ( Fig. 10 ). Mean peak echolocation CF frequency is 106 kHz (104–108 kHz; Table 2 ).

Distribution and biology: So far, it appears that this tiny species is restricted in its distribution to Gorongosa National Park in Mozambique ( Fig. 11 ), although we provisionally refer a very small adult individual from Mount Inago in Mozambique to this taxon. Molecular sequences are required from a wider range of localities to determine the range of this taxon. Given that the two individuals sequenced from Gorongosa National Park were distinct from each other, the possibility exists that more than one cryptic species may be present.

Figures

Figure 2. Bayesian tree of partial Cytb sequences, with nodal support values based on Bayesian probabilities and bootstrap values for Maximum Likelihood and Maximum Parsimony. Samples included in all analyses (molecular, morphometric and bacular) are underlined.

Figure 3. Haplotype network using minimum-spanning inference method based on 667 base pairs of Cytb.

Figure 4. PCA variation for five log-transformed cranial variables for six proposed small southern Africa Rhinolophus spp. defined on molecular and morphological grounds.

Figure 5. Biplot showing the first and second principal components from a PCA of 2D landmark data for small southern Africa Rhinolophus spp., including data from type specimens of R. saeinnyi and R. s. rhodesiae. Deformation grids illustrate cranial shape changes associated with each PC.

Figure 6. Overall lateral cranial morphology of small southern African Rhinolophus taxa as illustrated by deformation grids (exaggerated 3×).

Figure 7. Biplot showing the first and second principal components from a PCA of eight bacular measurements for small southern Africa Rhinolophus taxa. Numbers indicate the position of taxa referred to in Table 5.

Figure 8. Dorsal, lateral and ventral views (from left to right) of bacula of nine of the ten taxa as identified by PCA of bacular measurements. Scale bars = 1 mm.

Figure 9. Noseleaf structure of representatives of various Rhinolophus taxa (not drawn to scale).

Figure 10. Occlusional views of the maxillary toothrows of the various Rhinolophus taxa detailed in this study. Arrows indicate the position of the small anterior premolar.

Figure 11. Final distribution of small Rhinolophus species classified according to the present study.

Figure 12. Portraits of: A, the lateral facial profile showing the connecting process (marked by arrow); B, general noseleaf morphology; and, C, in flight behaviour of Rhinolophus gorongosae sp. nov. (Photographs by P. Naskrecki.)