Research Article |
Corresponding author: Zhongzheng Chen ( zhongzheng112@126.com ) Corresponding author: Xuelong Jiang ( jiangxl@mail.kiz.ac.cn ) Academic editor: Nedko Nedyalkov
© 2024 Xiaoxin Pei, Zhongzheng Chen, Quan Li, Xueyou Li, Changzhe Pu, Kang Luo, Jing Luo, Mingjin Pu, Hongjiao Wang, Laxman Khanal, Xuelong Jiang.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Pei X, Chen Z, Li Q, Li X, Pu C, Luo K, Luo J, Pu M, Wang H, Khanal L, Jiang X (2024) A new species of the genus Soriculus (Soricidae, Eulipotyphla, Mammalia) from Medog in the eastern Himalaya. ZooKeys 1195: 139-155. https://doi.org/10.3897/zookeys.1195.115699
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Himalayan shrews of the genus Soriculus (Soricidae, Eulipotyphla), currently represented by four nominal species, are endemic to the Himalayas and the Gaoligong Mountains. In April 2022 and April 2023, a total of 10 specimens of Soriculus were collected from Beibeng and Damu, Medog County, Tibet, China. The morphology of the specimens was compared with the four recognised species of the genus Soriculus. Additionally, two mitochondrial (Cyt b and 12S) and three nuclear (APOB, BRCAI and RAG2) genes were sequenced to test the phylogenetic relationships of these specimens with the other species. Our results indicate that these specimens represent a distinct species, Soriculus beibengensis sp. nov., which is formally described here. The new species is distinguished from the other Soriculus species by the combination of darker pelages, smaller size, the relatively stubby nasal and the widened posterior processes of incisors. Phylogenetic analyses revealed the new species is sister to S. minor. The p–distance of Cyt b gene between S. beibengensis sp. nov. and other nominal Soriculus species ranges from 9.1–16.3%. This new species has a known distribution at an elevation of 1,500–2,125 m in Medog County, Tibet, China. The discovery of this new species from Medog County has important implications for interpreting small mammal biogeographic patterns in the eastern Himalaya and the mountain chains of south-west China.
Phylogeny, small mammals, taxonomy
The genus Soriculus Blyth, 1854 (Mammalia, Eulipotyphla, Soricidae) is an endemic genus in the Himalayas and Gaoligong Mountains and which is mainly distributed in countries and regions across the eastern Himalayas (Bhutan, Sikkim of India, Nepal, and Yunnan and Tibet of PR China) (
For a long time, Episoriculus Ellerman and Morrison-Scott, 1966 and Chodsigoa Kastchenko, 1907 were considered subgenera or junior synonyms of the genus Soriculus (
Medog is located in the eastern Himalayas with complex climate and geographic structure, making a biodiversity rich region. Due to the remoteness of Medog and the limited field surveys in the area, the biodiversity has remained poorly known and underestimated. Multiple new taxa have been recently described from the area, including mammals, for example, one new genus and species of mole (
A total of 10 Soriculus specimens of S. beibengensis sp. nov. were collected from Medog, Tibet, China in April 2022 (
Five external measurements: weight (W), ear length (EL), head and body length (HBL), hind foot length (HL) and tail length (TL) were measured in the field and were reported to the nearest 0.1 g (for weight) or 0.5 mm (for different length categories). Eighteen craniodental metrics were measured using a digital caliper graduated to 0.01 mm following
Summary statistics (mean, standard deviation, ranges and number of samples) of external and skull measurements (in millimetres) of Soriculus specimens used in the study; character abbreviations are detailed in the “Material and methods”.
S. beibengensis sp. nov. | S. minor | S. nigrescens | S. medogensis | S. nivatus | |
---|---|---|---|---|---|
W | 11.7 ± 1.4 | 8.9 ± 1.2 | 17.6 ± 2.5 | 13.3 ± 0.7 | 11.7 ± 1.7 |
8.8–13.2; 10 | 7.7–12.1; 21 | 12.9–20.7; 11 | 12–14.1; 7 | 9.6–15.3; 23 | |
HBL | 77.2 ± 4.1 | 71 ± 3.9 | 88.6 ± 3.4 | 84.7 ± 0.8 | 82.6 ± 4.1 |
70–81; 10 | 62–77; 20 | 83–93; 11 | 83–85; 7 | 70–90; 23 | |
TL | 40.6 ± 1.8 | 36.7 ± 4.1 | 45.8 ± 3.2 | 50.7 ± 3.6 | 51.6 ± 2.7 |
38–44; 10 | 31.5–43; 21 | 42–52; 11 | 43–54; 7 | 46–58; 23 | |
HF | 12.6 ± 1.1 | 12.3 ± 0.6 | 15.4 ± 0.9 | 14.9 ± 0.7 | 15.3 ± 1 |
11–14; 10 | 11–13.5; 21 | 14–17; 11 | 14–16; 7 | 13–17; 23 | |
EL | 8.1 ± 1.4 | 7.9 ± 1.1 | 8.7 ± 0.9 | 10.3 ± 1 | 9.3 ± 1.2 |
6–10; 10 | 6–10; 6 | 8–11; 11 | 9–12; 7 | 7–12; 23 | |
CIL | 20.8 ± 0.3 | 19.6 ± 0.4 | 23.4 ± 0.5 | 23.7 ± 0.7 | 23.4 ± 0.3 |
20.4–21.3; 10 | 19.2–20.2; 7 | 22.5–24.2; 9 | 22.7–24.5; 4 | 22.8–24.1; 22 | |
PIL | 9.3 ± 0.2 | 8.9 ± 0.2 | 10.7 ± 0.2 | 11.1 ± 0.2 | 10.7 ± 0.2 |
9–9.5; 10 | 8.6–9.3; 6 | 10.4–11.1; 10 | 10.8–11.5; 5 | 10.4–11.1; 22 | |
BL | 18.4 ± 0.3 | 17.4 ± 0.3 | 20.8 ± 0.5 | 21 ± 0.7 | 20.7 ± 0.3 |
17.9–19; 10 | 17–17.9; 7 | 19.9–21.4; 9 | 20.1–21.7; 4 | 20.1–21.3; 22 | |
UTL | 9 ± 0.2 | 8.5 ± 0.2 | 10.2 ± 0.2 | 10.8 ± 0.2 | 10.3 ± 0.2 |
8.8–9.2; 10 | 8.3–8.9; 7 | 9.9–10.6; 9 | 10.6–11; 5 | 10–10.7; 22 | |
P4M3 | 5.5 ± 0.1 | 5.3 ± 0.1 | 6.3 ± 0.1 | 6.4 ± 0.1 | 6.1 ± 0.1 |
5.3–5.6; 10 | 5.2–5.4; 7 | 6.2–6.5; 10 | 6.3–6.5; 5 | 6–6.3; 22 | |
IOB | 4.8 ± 0.1 | 4.8 ± 0.1 | 5.6 ± 0.5 | 5.4 ± 0.1 | 5.4 ± 0.1 |
4.6–5; 10 | 4.7–5; 7 | 5.3–6.9; 11 | 5.3–5.5; 5 | 5.2–5.6; 22 | |
DIF | 3.9 ± 0.1 | 3.7 ± 0.1 | 4.3 ± 0.1 | 3.9 ± 0.1 | 3.7 ± 0.1 |
3.7–4; 10 | 3.6–3.9; 7 | 4.2–4.5; 11 | 3.8–4; 5 | 3.6–3.9; 22 | |
CB | 10.7 ± 0.2 | 10.4 ± 0.3 | 11.7 ± 0.2 | 11.8 ± 0.3 | 11.4 ± 0.2 |
10.2–11; 10 | 9.8–10.7; 7 | 11.5–11.9; 10 | 11.3–12.1; 4 | 11.2–11.7; 22 | |
CH | 6.3 ± 0.2 | 6.2 ± 0.2 | 6.8 ± 0.1 | 7 ± 0.2 | 7 ± 0.1 |
6–6.5; 10 | 5.9–6.6; 7 | 6.7–7; 10 | 6.8–7.2; 4 | 6.8–7.5; 22 | |
MB | 6.2 ± 0.2 | 6 ± 0.1 | 7.1 ± 0.2 | 6.9 ± 0.1 | 6.6 ± 0.1 |
5.7–6.5; 10 | 5.8–6.1; 7 | 6.9–7.4; 11 | 6.8–7; 5 | 6.3–6.8; 22 | |
M2M2 | 5.9 ± 0.2 | 5.7 ± 0.1 | 7 ± 0.1 | 6.8 ± 0.2 | 6.3 ± 0.1 |
5.6–6.1; 10 | 5.6–5.8; 7 | 6.9–7.1; 11 | 6.7–7.2; 5 | 6–6.6; 22 | |
PPD | 3.9 ± 0.1 | 3.9 ± 0.1 | 4.5 ± 0.1 | 4.6 ± 0.1 | 4.3 ± 0.1 |
3.8–4; 10 | 3.8–4; 6 | 4.3–4.7; 11 | 4.5–4.7; 5 | 4.2–4.5; 22 | |
BMF | 3.6 ± 0.1 | 3.4 ± 0.2 | 3.7 ± 0.1 | 3.5 ± 0.2 | 3.5 ± 0.1 |
3.5–3.8; 10 | 3.1–3.6; 7 | 3.5–3.9; 10 | 3.2–3.8; 4 | 3.2–3.7; 22 | |
ML | 11.6 ± 0.2 | 10.8 ± 0.2 | 12.8 ± 0.4 | 13.6 ± 0.3 | 13.2 ± 0.3 |
11.3–11.9; 9 | 10.5–11; 7 | 12.3–13.4; 11 | 13.3–14.1; 5 | 12.5–13.7; 22 | |
LTR | 8.3 ± 0.2 | 7.8 ± 0.2 | 9.1 ± 0.3 | 9.8 ± 0.1 | 9.5 ± 0.2 |
8–8.5; 9 | 7.7–8.1; 7 | 8.7–9.6; 11 | 9.7–10; 5 | 8.9–9.7; 22 | |
HCP | 4.9 ± 0.2 | 4.7 ± 0.2 | 5.9 ± 0.2 | 6.7 ± 0.1 | 5.6 ± 0.3 |
4.5–5.1; 10 | 4.5–4.9; 7 | 5.7–6.1; 11 | 6.6–6.9; 5 | 4.6–6; 22 | |
HCV | 3.1 ± 0.1 | 2.9 ± 0.1 | 3.7 ± 0.1 | 3.8 ± 0.1 | 3.2 ± 0.1 |
3–3.2; 10 | 2.7–3.1; 7 | 3.5–3.8; 11 | 3.7–3.9; 5 | 3.1–3.5; 22 | |
HAC | 3.8 ± 0.2 | 3.6 ± 0.1 | 4.5 ± 0.2 | 4.6 ± 0.1 | 4.3 ± 0.1 |
3.7–4.1; 10 | 3.4–3.8; 7 | 4.2–4.8; 11 | 4.5–4.8; 5 | 4–4.5; 22 |
Comparative morphological data of another 62 Soriculus specimens including S. nigrescens (11), S. nivatus (23), S. medogensis (7) and S. minor (21) were obtained from
The total genomic DNA of five S. beibengensis sp. nov. specimens was extracted from muscle or liver using a DNA extraction kit (Qiagen DNeasy Blood and Tissue Kit, Germany). Two mitochondrial genes (complete cytochrome b, Cyt b and segment of 12S rRNA, 12S) and segments of three nuclear genes (apolipoprotein B, APOB; breast cancer 1, BRCA1; and recombination activating protein 2, RAG2) were amplified using primers and PCR conditions similar to
Three concatenated datasets were used for the phylogenetic analyses: (1) mitochondrial genes (mtDNA, Cyt b + 12S, 1963 bp), (2) nuclear genes (nDNA, APOB + RAG2 + BRCA1, 1974 bp) and (3) the mitochondrial and nuclear genes (mtDNA + nDNA, Cyt b + 12S + APOB + RAG2 + BRCA1, 3937 bp). Maximum-Likelihood (ML) and Bayesian Inference (BI) methods were used to reconstruct phylogenetic relationships. The ML phylogenies were inferred using IQ-TREE (
We estimated divergence time using BEAST v.2.6.7 (
A summary of the external and cranial measurements of the five species under the genus Soriculus is given in Table
Craniodental variation in Soriculus, based on principal component analysis (PCA). Character abbreviations are detailed in the “Material and methods”.
Character | PC1 | PC2 |
---|---|---|
UTL | 0.973 | 0.168 |
PIL | 0.972 | 0.166 |
CIL | 0.960 | 0.178 |
ML | 0.955 | 0.056 |
LTR | 0.952 | 0.002 |
BL | 0.950 | 0.202 |
CH | 0.935 | -0.022 |
P4M3 | 0.916 | 0.356 |
PPD | 0.869 | 0.409 |
HAC | 0.839 | 0.452 |
CB | 0.839 | 0.458 |
HCP | 0.826 | 0.398 |
IOB | 0.743 | 0.371 |
M2M2 | 0.695 | 0.681 |
MB | 0.674 | 0.670 |
DIF | 0.100 | 0.932 |
BMF | -0.096 | 0.717 |
HCV | 0.625 | 0.668 |
Eigenvalue | 13.727 | 6.862 |
Variance explained | 66.620 | 21.550 |
In total, we obtained 3937 bp long sequences for five specimens of S. beibengensis, including 1140 bp Cyt b, 823 bp 12S, 507 bp APOB, 693bp RAG2 and 774 bp BRCA1. All new sequences have been deposited in the GenBank (Accession Numbers: PP213259–PP213263 and PP226949–PP226968, Suppl. material
The phylogenetic tree inferred using Bayesian Inference (BI). The figure shows phylogenetic trees derived from A the mitochondrial genes B the nuclear genes, and C the mitochondrial and nuclear genes. The branch numbers indicate ultrafast bootstrap values (left) and BI posterior probabilities (right).
The divergence time of Soriculus species inferred from a time-calibrated phylogeny, based on the nuclear genes in BEAST v.2.6.7. The node numbers represent the median ages of the divergence times (upper) and posterior probabilities (below). The branch lengths represent divergence time, node bars indicate the 95% CI for each clade age and red bars indicate the calibration points.
Beibeng large-clawed shrew, 背崩大爪鼩鼱.
Holotype. KIZ042755, adult female, collected on 08 April 2023 by Mingjin Pu, at Beibeng Town, Medog County, southeast Tibet, China (29.219°N, 95.189°E, 1610 m a.s.l.). Dried skin, cleaned skull and muscle tissue are deposited in KIZ.
Paratypes. Five specimens KIZ042756 (adult female), KIZ042757 (adult female), KIZ042758 (adult female), KIZ042759 (adult female), KIZ042760 (adult female). Collected from the type locality at Medog in April 2023 at elevations from 1500 m to 2125 m. All specimens are deposited in KIZ.
Four specimens KIZ042761 (adult female), KIZ042762 (adult male), KIZ042763 (adult female), KIZ042764 (adult female).
The specific Latin name beibengensis named for Beibeng, the type locality, with the Latin adjectival suffix –ensis means “belonging to”.
The new species is assigned to the genus Soriculus, based on the typically enlarged forefeet and claws (Fig.
Amongst five species of the genus Soriculus, S. beibengensis sp. nov. is the second smallest species. Its size is larger than S. minor, but smaller than S. nivatus, S. nigrescens and S. medogensis (Table
The skull is distinctly smaller than S. nivatus, S. nigrescens and S. medogensis, but larger than S. minor. Braincase is low and relatively flattened and the posterior of the skull is rounded. The sagittal and lambdoidal crest are well-developed and clear, the latter is especially prominent. The nasal and rostrum are not clearly transitioned and are stubby. The posterior process of incisor is widened, forming a narrowed funnel-shaped channel between the processes of adjacent teeth. The basioccipital and basisphenoid are fused and narrowed markedly in the middle region, forming a spade-like structure (Fig.
The coronoid process is high and straight, with a concave anterior surface and a spatulate tip. The condyloid process has a single slender point and is angled upward at roughly 45 degrees, with the tip sitting below the coronoid process (Fig.
Amongst species of the genus Soriculus, S. beibengensis sp. nov. is morphologically similar to its sister species, the S. minor. Both of them have a darker pelage and smaller size than other species. However, the new species can be distinguished from S. minor by multiple features. S. beibengensis sp. nov. is larger than S. minor for most of the external and craniomandibular measurements (Table
Soriculus beibengensis sp. nov. can be easily distinguished from S. nigrescens, S. nivatus and S. medogensis by its smaller size, the darker pelage colour and almost no pigmentation of the teeth (Fig.
Soriculus beibengensis sp. nov. is known only from the type locality in Beibeng and Damu Town, Medog, Tibet, China at elevations from 1501 to 2123 m a.s.l. They were mainly distributed in mixed forest dominated by oak and a few individuals were distributed in conifer-broadleaf mixed forest.
The genus Soriculus is one of the least-studied small mammals. Owing to the limited studies, several species were not described until recently and it was considered a monotypic genus for a long time (
As research has progressed, the evolutionary relationships amongst species of the genus Soriculus have become clearer. The genus is mainly split into two clades, representing two different evolutionary processes. The fossil evidence of Nectogalini shows that different taxa in this family migrated southwards from the late Miocene to the early Pleistocene (
1 | Small; CIL < 22.0 mm, ML < 12.0 mm | 2 |
– | Large; CIL > 22.0 mm, ML > 12.0 mm | 3 |
2 | CIL < 20.3 mm, ML < 11.2 mm | S. minor |
– | CIL > 20.3 mm, ML > 11.2 mm | S. beibengensis sp. nov. |
3 | Mandible well developed, the ramus region broader and coronoid process is high, HCP > 6.6 mm | S. medogensis |
– | Mandible less developed, the ramus region is narrow and coronoid process is short, HCP < 6.1 mm | 4 |
4 | Maxillary region narrower, teeth are slender, M2M2 < 6.6 mm | S. nivatus |
– | Maxillary region broader, teeth are robust, M2M2 > 6.8 mm | S. nigrescens |
The authors have declared that no competing interests exist.
No ethical statement was reported.
The study was supported by the Survey of Wildlife Resources in Key Areas of Tibet (ZL202203601), the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0501), the National Key R&D Program of China (2022YFC2602500), the National Natural Science Foundation of China (31900318) and the University Synergy Innovation Program of Anhui province (GXXT-2020-075).
Data curation: HW. Investigation: QL, XL, CP, JL, KL, MP. Writing – original draft: XP. Writing – review and editing: XJ, ZC, LK.
Xiaoxin Pei  https://orcid.org/0000-0001-7137-2600
Zhongzheng Chen  https://orcid.org/0000-0003-3821-0145
Quan Li  https://orcid.org/0000-0001-7536-5475
Laxman Khanal  https://orcid.org/0000-0003-2411-3627
Xuelong Jiang  https://orcid.org/0000-0003-2052-2490
All of the data that support the findings of this study are available in the main text or Supplementary Information.
The best-fit partitioning schemes and evolutionary models estimated using PartitionFinder
Data type: xlsx
Samples, sampling localities and DNA sequences used for molecular analyses
Data type: xlsx