Soriculus nigrescens ( Gray, 1842 )

Chen, Zhongzheng, Pei, Xiaoxin, Hu, Jiangxiao, Song, Wenyu, Khanal, Laxman, Li, Quan & Jiang, Xuelong, 2024, Multilocus phylogeny and morphological analyses illuminate overlooked diversity of Soriculus (Mammalia: Eulipotyphla: Soricidae), with descriptions of two new endemic species from the eastern Himalayas, Zoological Journal of the Linnean Society 201 (2), pp. 534-548 : 541-543

Soriculus nigrescens ( Gray, 1842) ( Table 1 )

Corsira nigrescens Gray, 1842: 261 . Type locality: Darjeeling , India .

Soriculus nigrescens pahari Hinton, 1922: 1053 . Type locality: Gnatong , Sikkim.

Soriculus nigrescens caurinus Hinton, 1922: 1054 . Type locality: Kumaon , India.

Soriculus nigrescens centralis Hinton, 1922: 1054 . Type locality: Bouzini , Nepal.

Suggested common name: Himalayan shrew; kmŧDzẽē.

Type locality: Darjeeling, India

Remarks: Sizeisthelargestinthegenus Soriculus (W = 17.6 ± 2.5 g, HB = 89 ± 3 mm; Table 1 ). Dorsal pelage colour varies from brown to black, ventral paler (Supporting Information, Fig. S2 ). Tail is not sharply bicolored. Most individuals have a tail length ≤ 50 mm, averaging 52% of head and body length. Foreclaws are enlarged. The skull is broad, with the widest maxillary region in the genus ( Fig. 6 ). Braincase is flattened, and the posterior of the skull is angular rather than rounded. The basioccipitalbasisphenoid of S. nigrescens is well developed. The first upper incisor is small and the apex is straight downwards. There are four upper unicuspids; U 2 is the largest, whereas U 4 is minute. M 3 is reduced. The tips of teeth are slightly pigmented with orange or light red.

Comments: Soriculus nigrescens caurinus , S. n. centralis, and S. n. pahari were described as subspecies of S. nigrescens ( Hinton 1922) , but all of them were then considered as synonyms of S. n. nigrescens ( Mitchell 1977, Hoffmann 1985). We examined the photos of type specimens (Supporting Information, Fig. S3 ) of the three forms, which show similar cranial features to S. nigrescens but distinct from the two new species (i.e. Soriculus sp. 1 and Soriculus sp. 2 ) we described below. First, the broader maxillary region and more robust teeth of S. n. caurinus, S. n. centralis, and S. n. pahari are corresponding to those in S. nigrescens , but distinguished from Soriculus sp. 1 (e.g. M 2 M 2 = 6.9 mm in caurinus; M 2 M 2 = 6.8 mm in centralis; M 2 M 2 = 6.9 mm in pahari; M 2 M 2 = 6.3 ± 0.1 mm, range 6.0– 6.6 mm in Soriculus sp. 1 ; Table 1 ). The coronoid process of the three forms is similar to that of S. nigrescens , but much shorter than that of Soriculus sp. 2 (e.g. HCP = 5.6 mm in caurinus; HCP = 5.9 mm in centralis; HCP = 5.9 mm in pahari; HCP = 6.7 ± 0.1 mm, range 6.6–6.9 in Soriculus sp. 2 ; Table 1 ). Second, according to the measurements provided by Hinton (1922), the tail length of three subspecies (TL ≤ 48 mm) is similar to S. nigrescens (normally <50 mm) but shorter than the two new species (normally> 50 mm). Third, the two new species are restricted to the eastern Himalayas and are geographically distinct from the three subspecies (within the range of S. nigrescens ). We therefore place them as synonyms of S. nigrescens . The pelage of the three forms is lighter and browner than the black coloured specimens collected in China, indicating a variation in colour of this species ( Mitchell 1977).

Distribution: The species has a wide distribution in the southern Himalayas, from Nepal through northern India (Uttarakhand, West Bengal, and Sikkim), Bhutan, northern Myanmar to southern Tibet (Medog, Chayu, Milin, Yadong, Nielamu, and Dingri), China. According to the distribution range, records from Nepal and northern India (see Jenkins 2013) are likely to be of this species. It occupies a wide elevation range from 700 m to 4500 m a.s.l. In Medog county, most of the individuals occur at elevations below 1450 m a.s.l.

Figures

Figure 2. Results of the principal components (A) and discriminant function analysis (B) analysis of Soriculus based on the 18 log10- transformed craniomandibular variables.

Figure 3. Phylogenetic trees of the genus Soriculus based on (A) the concatenated mtDNA and (B) the concatenated nDNA using the ML and BI methods.Node numbers indicate Bayesian posterior probabilities (PP) and ultrafast bootstrap supports (UFBoot).

Figure 6. Dorsal, ventral, and lateral views of the skull and lateral view of the mandible of (A) S. nigrescens (MT201904155), (B) S. nivatus (holotype, MT1904951), (C) S. medogensis (holotype, MT201811181), and (D) S. minor (TC-H-KIZ 2345).