Pipistrellus babu Thomas, 1915

Saikia, Uttam, Chakravarty, Rohit, Csorba, Gabor, Laskar, Mostaque Ahmed & Ruedi, Manuel, 2025, Taxonomic reassessment of bats from the Western Himalayas, India and description of a new species of the Myotis frater complex (Mammalia, Chiroptera, Vespertilionidae), Zootaxa 5644 (1), pp. 1-78 : 50-52

25. Pipistrellus babu Thomas, 1915

(Babu’s Pipistrelle)

New material: 2 M, 08.06.2017, Narkanda, Shimla district , Himachal Pradesh, V /M/ERS/434, 486; 1 F , 13.06.2017, Salogra, Solan District , Himachal Pradesh, V /M/ERS/452; 1 F , 10.06.2017, Derghat, Solan District , Himachal Pradesh, V /M/ERS/483; 2 M , 4.06.2017, Sangla, Kinnaur District , Himachal Pradesh, V /M/ERS/484, 485; 1 M , 09.06.2017, Narkanda, Shimla District , Himachal Pradesh, V /M/ERS/486; 1 F , 11.06.2017, Kandaghat, Solan District , Himachal Pradesh, V /M/ERS/487; 1 M , 08.03.2019, Mandal, Chamoli district , Uttarakhand, V /M/ERS/639; 1 M , 10.04.2021, Mandal, Chamoli District , Uttarakhand, V /M/ERS/652 .

Morphological description of specimens: All individuals had dark brown dorsal pelage speckled with russet brown hairs, especially on the flanks. The ventrum was lighter brown. Individual hairs on both sides were dark brown except for the tips which were slightly lighter ( Fig. 22 ). The muzzle and ear were dark brown. The ears had four distinct ridges and were broadly triangular in shape. The tragus was of medium length and width, the anterior margin was almost straight while the posterior border was curved inward. The wings were attached to the base of the toes. Well–developed keels on calcars were present. All the examined males had a comparatively long (8–8.4 mm) pendulous penis, hirsute at the distal end ( Fig. 22 ).

The skull had a relatively broad rostrum with a linear depression in the midline. The nasal notch was V shaped. In lateral view, the skull profile was straight except for the frontal region which gently elevated and then descended ( Fig. 23A ). The basisphenoid pits were deep and oval in shape. The posterior border of the palate had a small, pointed projection. The coronoid processes of mandibles were gently elevated from the condyle, however in one of our specimens ( V /M/ERS/484), the coronoid process was raised at a higher angle although it did not exceed the lower canine in height.

The first upper incisors did not have an obvious secondary cusp. The second incisor was slightly shorter than the first. A strong secondary cusp in the canine was visible on all specimens. The first premolar was small and intruded in the tooth row, although visible from outside. The canine and second upper premolar were not in contact. All these characteristics conformed well to the descriptions and type of Pi. babu Thomas, 1915 .

The bacula of three specimens ( V /M/ERS/639, 484 and 486) from three different localities in Himachal Pradesh were thin and long (5.5–5.8 mm). The distal end bifurcated into a fork with prongs of variable length and the proximal ends gradually enlarged and divided into two halves by a deep grove. In lateral view, they appeared almost straight with forward curving ends ( Fig. 24 ). The width at the base was 0.8–0.9 mm .

DNA: We sequenced the COI and CYTB of six individuals of Pi. babu from Himachal Pradesh (M 2222/ V /M/ERS/485, M 2223/ V /M/ERS/484, M 2225/ V /M/ERS/486, M 2264/ V /M/ERS/483, M 2265/ V /M/ERS/487and M 2266/ V /M/ERS/452). These sequences were all very similar (<1% K2P), and clearly represented a single species ( Tables S2 and S 3). COI sequences from an unidentified pipistrelle from Uttarakhand and reported by Chakravorty et al. (2020) as “ Pi. cf. ceylonicus ” was in fact identical to these Himachal specimens and thus also assigned here to Pi. babu . Furthermore, multiple sequences of both genes and labelled as “ javanicus ” in the GenBank were clustered in very distinct (>12% K2P distance) and non–monophyletic clades; ( Figs 4 and 6). The Western Himalayan Pi. babu is thus genetically very distinctive from any other sequenced pipistrelle.

Echolocation call: We recorded the calls of 36 released individuals in KWLS. Echolocation calls were typical of Pipistrellus species with distinct FM and QCF components. On average the release calls were 5.7 ms long, with average bandwidth of 47 kHz, end frequency of 35 kHz and peak frequency of 40 kHz. These call characteristics overlapped with those of the much larger My. sicarius and may also be confusable with Mirostrellus joffrei calls emitted in clutter ( Chakravarty et al. 2020).

Locality records and ecological notes: The type specimen of Pi. babu was collected from Murree (C. 3.9070°N, 73.3943°E, 2400 m) in Punjab province, Pakistan, in the Pir Panjal Range of Western Himalayas (Thomas 1915) and certainly represents its westernmost occurence. In India, this bat was reported in “Northern India and lower Himalayas. Other specimens were recorded from Gharial, Masuri, Simla, Kumaon, Nepal, Darjeeling, Sylhet, central Provinces” (Thomas 1915). Bhat (1974) recorded this species from Sukhidhang (1380 m) in Almora district, Srinagar (550 m) in Pauri, and Ghonti (920 m) in Tehri districts of Uttarakhand. We caught many individuals of this pipistrelle at several localities in Solan, Shimla and Kinnaur districts of Himachal Pradesh and in Chamoli district of Uttarakhand during the present surveys. The species is apparently common and widespread in the region. Csorba et al. (1999) reported specimens of Pi. “ javanicus” babu from Sudame and Banthanti in Central Nepal with a note that they should be considered specifically distinct from Pi. javanicus . Hill & Harrison (1987) reported specimens of Pi. babu from Nepal and from Pashok in Darjeeling in Eastern Himalaya of India. Das (2003) reported the dimensions of a few specimens of Pi. babu from Darjeeling. The external characters and cranial measurements of Darjeeling specimens conform well to our present specimens from Himachal Pradesh. The Field Museum of Natural History, Chicago and the Natural History Museum, London hold specimens of this species from Sikkim, Eastern and Western Assam (as Pi. javanicus babu in Bates & Harrison 1997). Our Western Himalayan specimens were recorded between elevations of 1500–3000 m whereas in Nepal, the species was recorded within elevations of 1500–2200 m ( Csorba et al. 1999).

Taxonomic notes: The diagnosis of Pi. babu by Thomas (1915) was based on a suite of characters including the presence of a distinct post–calcarial lobe, moderately long penis and well developed baculum (about 6 mm in length), flatter muzzle, deep basial pits, faint secondary cusp to the first upper incisor and small, intruded first premolars; all these characters perfectly matched the examined specimens from Himachal Pradesh. However, Corbet & Hill (1992) were in the opinion that babu “cranially and dentally agrees with javanicus ” and relegated the former as a subspecies of the latter. Most subsequent authors accepted this taxonomic arrangement and considered the two taxa as conspecific (i.e., Bates & Harrison 1997; Simmons 2005). Our direct comparison of the type specimen of Pi. babu and topotypic Pi. javanicus ( BMNH 1907.11.21.2 and 1909.1.5.296, respectively) revealed the following distinctive cranial features between both taxa: rostrum flatter, cranial profile more evenly ascending in Pi. babu (vs. rostrum deeper, profile more sharply ascending forming a bulbous anterior neurocranium in Pi. javanicus ; compare Figs 23A and 23B ); first upper incisor without evident secondary cusp (vs. present); anteorbital bridge wider (vs. narrow); basisphenoid pits well outlined and deep (vs. shallow, less demarcated). These traits were already noted by Csorba et al. (1999) in specimens of Pi. javanicus from Vietnam versus Pi. cf. javanicus [= Pi. babu ] from Central Nepal. We show here that the Himalayan specimens not only match the morphological description of Pi. babu , but also that they are genetically very distinct from any other sequenced pipistrelle ( Figs 4 and 6) and thus represent an independent species. Although the specific distinctness of Himalayan Pi. babu is clear, the taxonomic status of the pipistrelles called “ javanicus ” in northeastern India and elsewhere in the Oriental Region is far from resolved and reflects the difficulties to assign an appropriate species name to these Asian pipistrelles (e.g., Francis et al. 2010; Kruskop 2013). For instance, a series of sequences labelled “ Pipistrellus javanicus ” from Pakistan (e.g., GB MT081426 ) were in fact 99% identical to multiple European samples of Pi. kuhlii , indicating identification errors. Other haplotypes for various genes labelleld " Pipistrellus javanicus ” in GenBank also form multiple independent clusters which probably represent a taxonomic morass rather than a real polyphyly of a single species ( Francis et al. 2010). To solve which of those clusters corresponds to genuine Pi. javanicus , topotypic material from Indonesia should be investigated.

Figures

FIGURE 4: Neighbor-joining tree reconstruction of examined vespertilionids, miniopterids and molossids COI sequences and based on the K2P matrix in Table S2. Branches are proportional to the number of mutational steps. Sequence names are composed of the first two letters of the genus, followed by the species name, the GenBank number (or field number for newly sequenced samples), and the region of origin. Samples from India are highlighted in bold face.

FIGURE 22. Pictures showing dorso–ventral pelage colouration and side profile of Pi. babu specimens from localities in different physiographic zones of Himachal Pradesh. A) Greater Himalaya: Sangla (ZSI–NERC V/M/ERS/485), B) Lesser Himalaya: Narkanda (ZSI–NERC V/M/ERS/435), C) Siwalik Himalaya: Kandaghat (ZSI–NERC V/M/ERS/487), D) Close–up view of dorsal, ventral pelage and the penis of ZSI–NERC 487 and calcar lobe of ZSI–NERC V/M/ERS/485 specimens.

FIGURE 23. Dorsal, ventral, and lateral view of cranium and lateral and ventral view of mandible of A) Pi. babu from Himachal Pradesh (ZSI–NERC 486), and B) Pi. javanicus s.str. from Java (BMNH 1909.1.5.296).

FIGURE 24. Dorsal, ventral, and lateral view of the bacula of Pi. babu specimens from the Western Himalayas A) ZSI–NERC V/M/ERS/638, B) ZSI–NERC V/M/ERS/484, and C) ZSI–NERC V/M/ERS/486.