In plain sight : Bacular and noseleaf morphology supports distinct specific status of Roundleaf Bats Hipposideros pomona Andersen , 1918 and Hipposideros gentilis Andersen , 1918 ( Chiroptera : Hipposideridae )

The taxonomic status of Andersen’s Roundleaf Bat Hipposideros pomona (Chiroptera: Hipposideridae) and its relationship with the taxa assigned to it has been confusing. Knud Andersen described H. pomona (based on specimens from southern India) and H. gentilis (based on specimens from Myanmar) in 1918. Subsequently, the latter taxon was included under the former as a subspecies. Owing to disjunct distribution, it was speculated that these two taxa are distinct. Discovery of the type material and additional vouchers of both taxa in the National Collection of Zoological Survey of India, Kolkata allowed detailed comparison. Based on the morphological, craniodental and bacular characters, we establish the distinctness of these taxa. A redescription of H. pomona Andersen, 1918 is provided.


INTRODUCTION
The taxonomic status of Hipposideros pomona Andersen, 1918 sensu stricto has been confusing since its establishment.Knud Andersen's study on species allied to Hipposideros bicolor resulted in the description of two new species: H. pomona from southern India, and H. gentilis from northeastern India, Burma to west coast of Sumatra (Andersen 1918;Hill 1963;Hill et al. 1986;Douangboubpha et al. 2010) (Fig. 1).Andersen (1918) based his diagnosis of H. pomona in possessing broader than usual noseleaf, horseshoe and 'sella' (probably referring to posterior leaf) measuring 5.8mm and 5.2mm respectively, and forearm measuring 40.5 mm based on a single specimen from Coorg, southern India; while that of H. gentilis in possessing not broader than usual noseleaf, horseshoe and 'sella' measuring 4.5-5.5 mm and 3.7-4.8mm, and forearm measuring 38.5-41.5 mm based on specimens from Masuri, Pegu (=Bago), Burma (=Myanmar).In addition to the nominate gentilis, Anderson (1918) described three other subspecies of H. gentilis-sinensis, atrox, and major.Hill (1963) included pomona, gentilis, sinensis, atrox and major as subspecies of H. bicolor.Later, Hill et al. (1986) while revising H. bicolor considered H. pomona as distinct species including nominate form, gentilis, and sinensis, and assigned atrox and major to H. bicolor.A trend followed by subsequent authors (Yenbutra & Felten 1986;Zubaid & Davison 1987;Corbet & Hill 1992;Simmons 2005).The current known distribution of H. pomona sensu lato extends from India, Bangladesh, Nepal, Myanmar, Thailand, Laos, Cambodia, Viet Nam, south China and west Malaysia (Simmons 2005;Bates et al. 2008).Douangboubpha et al. (2010) opined that H. pomona (sensu Corbet & Hill 1992) might comprise two distinct species, pending further studies, with H. pomona being restricted in distribution to peninsular India and H. gentilis including the taxa gentilis and sinensis extending in distribution from northeastern India into Southeast Asia (Fig. 1).
Until now, there existed no information about the taxon H. pomona sensu stricto from southern India, as the type specimen (skin) was not traceable and the damaged skull (BMNH No. 18.8.3.4) in the British Museum of Natural History was the only material (Hill et al. 1986).During a museum study conducted by the authors, the type specimen in the type collection of the Zoological Survey of India, Kolkata was studied.Three more specimens from southern India (bearing ZSI No. 21535, and 7193 and 7196 collected from Travancore and Shevaroy Hills respectively) were found in the collection of ZSI, Kolkata by the first author.These specimens were originally labelled H. fulvus fulvus and have been catalogued as H. fulvus (Ghosh 2008).This species has been collected from southern India in the recent past, and the specimens are in personal collections of bat researchers in Tamil Nadu which have not been taxonomically studied.This recent discovery of additional specimens in National Zoological Collection of Zoological Survey of India provided us with an opportunity to conduct detailed study and compare this taxon with gentilis from northeastern India, Andaman Islands, and Myanmar.
Through this communication, we present evidence based on morphometric, bacular, and acoustic characters that prompt distinct specific status of the populations assigned from southern India as H. pomona, and northeastern India and Southeast Asia as H. gentilis.We also provide a detailed description of H. pomona as the original description of the taxon lacks detail.

MATERIALS AND METHODS
The present study is based on museum specimens in the National Zoological Collection, Zoological Survey of India, Kolkata and the Natural History Museum, Department of Zoology, Osmania University, Hyderabad, Telangana State.We examined a total of 10 specimens of H. pomona sensu lato (four vouchers including the type specimen (skin only) of H. pomona sensu stricto, and six vouchers including one voucher specimen of H. gentilis sensu stricto from Sagaing, Myanmar about 560km north of the type locality of gentilis).External and craniodental measurements were taken (to the nearest 0.1mm) using a digital vernier caliper (Mitutoyo make) following Bates & Harrison (1997) and Srinivasulu et al. (2010).Measurements of the museum specimens were compared with published data (from Douangboubpha et al. 2010;Bates & Harrison 1997).External measurements included FAforearm length, E -ear length, Tl -tail length, Tib -tibia length, Hf -hindfoot length, 3mt -third metacarpal, 4mt -fourth metacarpal, 5mt -fifth metacarpal, 1ph3mt -first phalanx of third metacarpal, 2ph3mt -second phalanx of third metacarpal, 1ph4mt -first phalanx of fourth metacarpal, 2ph4mt -second phalanx of fourth metacarpal.Craniodental measurements included GTL -greatest length of the skull, CBL -condylobasal length, CCL -condylocanine length, CM 3 -maxillary toothrow, C 1 -C 1 -anterior palatal width, M 3 -M 3 -posterior palatal width, ZB -zygomatic breadth, BB -braincase breadth, CM 3 -mandibular toothrow, M -mandible length.Statistical analyses were conducted in R (R Development Core Team 2013).One-way ANOVAs were used to select significant (p<0.05)variables for classification analysis.Of the 19 variables measured, 11 (GTL, CCL, CM 3 , C 1 -C 1 , M 3 -M 3 , ZB, FA, E, CM 3 , M, and HF) were selected for a principal component analysis (PCA).
The bacula of two male specimens (one each of pomona [ZSI No. 21535] from Kerala, India and gentilis [ZSI 131zz] from Myanmar) were extracted and prepared following the protocol outlined in Topal (1958), and later stored in glycerol.The information on the echolocation calls were sourced from published literature and our studies in Andaman Islands, India.
H. pomona pomona ZSI No. 7193, female, collected from Shevaroy Hills, Tamil Nadu by W. Daly, collection year not known, specimen only, skull in situ.
H. pomona pomona ZSI No. 7196, sex unknown, collected from Shevaroy Hills, Tamil Nadu by W. Daly, collection year not known, specimen damaged and tied up.

RESULTS
External measurements show that pomona is smaller than gentilis (FA 39.46-39.70mm vs. 39.70-44.1 mm) with shorter ears (16.76-17.03mm vs. 17.5-24.0mm).In both the taxa the third metacarpal was the shortest, being shorter than both the fourth and the fifth metacarpals, with fourth being the longest of the three.Similarly, the first phalanx of the third metacarpal was longer than the second and was almost equal to the combined lengths of the first and the second phalanges of the fourth metacarpal (Table 1).
The cranial measurements show that the condylocanine length of pomona being smaller than that of gentilis (14.66mm vs. 14.6-16.3mm).The zygoma are more widely placed in gentilis than in pomona.The anterior palatal width and the posterior palatal width are also greater in gentilis than in pomona (5.7-6.6 mm vs. 5.43-5.8mm) signifying that the rostrum of gentilis is broad and long.The mandible measures shorter in pomona in comparison with gentilis (10.05-10.1 mm vs. 10.4-11.8mm) (Table 2).The sagittal crest in gentilis is well developed, and extends up to the parietal region of the skull, whereas in pomona it is weakly developed.The lambdoid crests are also well developed in gentilis.The first lower premolar (pm 2 ) is half to two third the height of the second lower premolar (pm 4 ).The pm 4 is one third the height of the tall canine.The lower molars are equal to or shorter than the pm 4 .The coronoid process  Principal component analysis on 10 individuals of H. pomona and H. gentilis from India, Southeast Asia, and the Andaman Islands generated three separate groups: H. pomona from India, H. gentilis from Southeast Asia, and H. gentilis sensu lato from the Andaman Islands (Fig. 2).These groups are clearly separated from each other (PC1 explained 73.41% of the variance), which shows that H. CCL (0.567), ZB (0.395), M 3 -M 3 (0.267), CM 3 (0.249), CM 3 (0.232), and C 1 -C 1 (0.105).Only HF had negative factor loading (-0.043).This analysis supports that all the three taxa can be separated morphologically based on ear length and forearm length, and cranially based on greatest length of the skull, mandible length and condyle-canine length.
The penis is thin and long with a pointed tip in both the taxa.The baculum structure of pomona is distinct from that of gentilis.In pomona, the baculum is larger (1.367mm), bearing a long shaft ending with a bifid tip (present study) (Image 3A), while in gentilis it is simple, very small (0.4-0.8 mm) (present study; Douangboubpha et al. 2010), bearing a straight shaft narrowing to a bluntly rounded tip and a slightly expanded base (Douangboubpha et al. 2010) (Image 3B&C).Amongst the gentilis in some specimens both ends are same (present study based on specimens from northeastern India, Andaman Islands, and northern Myanmar) (Image 3C).
Basing on the distinctness of the structure of the baculum of the southern Indian specimen from that of Assam and Southeast Asia (present study; Douangboubpha et al. 2010), and on differences in morphometrics of the southern Indian specimens from that of gentilis, the peninsular Indian population is considered distinct here.The rest of the specimens from Nepal, northeastern India, Andaman Islands to Myanmar, southern China, Lao PDR, Thailand, Viet Nam, Cambodia, and Western Malaysia (Corbet & Hill 1992;Bates & Harrison 1997;Simmons 2005;Francis 2008;Douangboubpha et al. 2010) are here considered as H. gentilis Andersen, 1918.Owing to the disjunct distribution of the two taxa (Fig. 1), and considerable variations in bacular, morphological, and acoustic characteristics the resurrection of H. gentilis as a distinct species is well-supported.
Molecular phylogenetic studies to support the distinctness of Hipposideros pomona sensu stricto and H. gentilis sensu lato are in progress.

Diagnostic characters
A small to medium sized bat, with an average forearm length of 39.6mm (38.1-40.84mm).The noseleaf is longer than broad, and covers the muzzle.There are no supplementary leaflets.The internarial septum is thick, parallel sided, becomes broader as it is nearing the proximal end and slightly narrows to a broadly rounded tip.The skull is slender and has an average condylocanine length of 14.4mm (14.2-14.66mm).The first lower premolar (pm 2 ) is small, triangular in outline, and is one half of the height of the second lower premolar (pm 4 ).The pm 4 is about one half to two third the height of the tall canine.The baculum is long with a straight shaft, the proximal end of which is broad   4±0.3 (5.9-6.8) 11.1±0.4 (10.5-11.6)and bifid.

Descriptive characters
A small to medium sized bat with the forearm length ranging between 38.1-40.84mm.Ears are large (16.76-19.0mm) with ridges and rounded off tips.Feet are large (6.28-6.97mm).The wing membrane and the interfemoral membrane are attached on either side of the ankles.In preserved specimens, the ventral fur is pale in colour; the fur along the flanks and toward the distal part of the body is pale at the base and light brown on the mid-portion, with pale tips; face has pale brown to darkish brown fur; while the dorsal surface is fawn to dark brown with pale hair bases.On the wing the third metacarpal is shorter than the fourth and the fifth metacarpal, with the fourth being the longest.The first phalanx of the third metacarpal is almost equal to the combined lengths of the first and second phalanges of the fourth metacarpal.The second phalanx of the third metacarpal is shorter than the first.The noseleaf is longer than broad and covers the muzzle (Image 2A&B).There are no supplementary leaflets.The internarial septum is thick, parallel sided and becomes broader as it is nearing the proximal end, and slightly narrows to a broadly rounded tip (Image 2A&B).The oval shaped nares are situated on either side of the tip of the internarial septum.The narial lappets are fleshy and are located on the sides of the nares attached to the internal walls of the anterior leaf.There is not much of a gap between the internarial septum, the narial lappets and the internal walls of the noseleaf.The intermediate leaf is short and small, shorter than the posterior and the anterior leaves (Image 2A&B).Due to its small size the gap between the internarial septum and the intermediate leaf is more.The posterior leaf is slightly wider than the anterior leaf and is divided into four cells by means of three septa (Image 2A&B).Penis is thin, long with a pointed tip.The baculum is long (1.367mm) with a long straight shaft, the proximal end of which is broad and bifid (Image 3A).The distal end is four pronged, and shows an inner curvature on the ventral surface (Image 3A).
The skull is slender (Image 1A) and has an average condylo-canine length of 14.4 mm (14.2-14.66mm).The rostrum is short with the CM 3 measuring 5.4-5.7mm.The palate is narrow as is seen by the posterior palatal width being 5.3-5.6 mm and the anterior palatal width being 3.15-3.4mm.The zygoma are slender toward the anterior portion, with a low jugal process on the posterior portion (Image 1A).The sagittal crest is weakly developed, and is visible on the anterior part of the braincase and not present on the posterior part.that it was found in an old well in Venginiserry, Thrissur District, Kerala (A.Madhavan pers.comm.October 2016), and it is found in a mixed landscape of plantations interspersed with tropical rainforest fragments, streams and riverine vegetation (Wordley et al. 2014;Juliet Vanitharani pers. comm. September 2017).

Distribution
H. pomona is known from Haleri, Coorg District, Karnataka; Venginiserry, Thrissur District, Kerala and Madhovaram in Tamil Nadu.It was recorded recently (Wordley et al. 2014) from Valparai Plateau in Tamil Nadu.It also occurs in Kalakkad-Mundhunthurai Tiger Reserve in Tamil Nadu (Juliet Vanitharani pers.comm.September 2017).Our recent surveys conducted in the 2017 in Haleri, Coorg District, Karnataka and many locations in Kerala was not successful in detecting the presence of this species.The habitat has changed over the years in the areas where this species was historically found.

Conservation status
H. pomona sensu lato, according to Bates et al. (2008) included both the taxa pomona and gentilis, was assessed as Least Concern.In the light of new information and upgradation of these taxa as distinct species, with H. pomona being known south of Coorg in Western Ghats and H. gentilis being present from Nepal, northeastern India through Myanmar to Southeast Asia, there is a need to reassess these two species.

Remarks on misidentified specimens
A specimen (ZSI No. 19450) from Macherla, Andhra Pradesh labelled as H. pomona pomona, collected by B. Nath in 1962 (Bates & Harrison 1997;Ghosh 2008) is hereby identified as H. fulvus basing on the structure of internarial septum and morphometrics.Three specimens collected by Indraneil Das from Andaman & Nicobar Islands and labelled as H. larvatus leptophyllus (ZSI Reg.No. 24773-75) are hereby identified as H. gentilis based on noseleaf structure and morphometrics.

Figure
Figure 2. Principal component analysis of Hipposideros pomona sensu stricto and Hipposideros gentilis