Mesechinus orientalis, Shi & Yao & He & Bai & Zhou & Fan & Su & Nie & Yang & Onditi & Jiang & Chen, 2023

Shi, Zifan, Yao, Hongfeng, He, Kai, Bai, Weipeng, Zhou, Jiajun, Fan, Jingyi, Su, Weiting, Nie, Wenhui, Yang, Shuzhen, Onditi, Kenneth O., Jiang, Xuelong & Chen, Zhongzheng, 2023, A new species of forest hedgehog (Mesechinus, Erinaceidae, Eulipotyphla, Mammalia) from eastern China, ZooKeys 1185, pp. 143-161 : 143

Mesechinus orientalis sp. nov.

Suggested common name.

Eastern Forest Hedgehog, 华东林猬 (Huadong Linwei).

Type materials.

Holotype: XC 23001, an adult male collected from Xikou Town (30°34'42"N, 118°41'47"E), Xuancheng City, southern Anhui, China, Zifan Shi leg., May 2023. The dried skin, cleaned skull, and tissue samples are deposited in AHNU. Paratypes: XC 18001, XC 2205001, XC 2205003, XC 2205005, XC 2205006, HZ 22001, six adult specimens collected from southeast Anhui and northwest Zhejiang, China, between 2018 and 2023. The specimens are deposited in AHNU.

Etymology.

The specific name orientalis is derived from the Latin oriens, "the east", and suffix - alis, "pertaining to", in reference to the new species’ eastern distribution in Anhui and Zhejiang provinces in eastern China.

Diagnosis.

This is a small-bodied hedgehog (GLS = 49.95 ± 1.69 mm), similar to M. hughi , but smaller than other Mesechinus species. It has the shortest spines in the genus (18-20 mm); the spines have four-colour rings, similar to the spines of M. dauuricus and M. hughi , but different from those of M. miodon and M. wangi (Fig. 8 ). The parietal is higher than the frontals, which differs from that of M. hughi and M. wangi (Fig. 9 ). The P2 is two-rooted and not completely fused (Fig. 4 ). The protocone of P3 is vestigial, which differs from that of M. hughi , and smaller than P2, which distinguishes it from M. dauuricus. The dental formula of M. orientalis sp. nov. [I 3/2, C1/1, P 3/2, M 3/3 ( × 2) = 36], which distinguishes it from M. wangi .

Description.

This is a small-bodied Mesechinus species (HB = 188.83 mm; GLS = 49.95 mm) (Table 2 ). The ears are small and nearly the same length as the surrounding spines (Fig. 8 ). The nose is brown, with black whiskers on the snout; these whiskers shorten towards the nose. The spines are the shortest (18-20 mm) among Mesechinus species. There are four colour rings on the spine from the base to the tip: two-thirds of the length is white at the base, followed by a 3-4 mm black ring, a narrow light ring, and a black tip (Fig. 8 ). This species appears to be sexually dimorphic; among the specimens we collected, the pelage of males was generally grey, while that of most of the females (2 of 3 specimens) was reddish brown. However, this is a relatively small sample size, and further investigation is required to establish sexual dimorphism with more certainty.

The skull is heavy and with a shortened rostrum, and the lambdoidal crest is evident. The parietal is relatively higher than the frontal (Fig. 9 ). On the ventral side of the skull, a posterior palatal shelf and vestigial posterior palatal spine (<1 mm) extend slightly posteriorly. The suprameatal fossa is moderately developed and has the anterior and posterior rim nearly parallel, giving the fossa a more angular or U-shaped appearance. The zygomatic arches are significantly expanded, and the temporal fossa is large and subrounded. The middle palatine foramen is relatively larger than in other Mesechinus species. The coronoid process of the mandible is tall, rising upward from the posterior of the toothrow; the tips are slightly curved to the posterior, and the posterior surface is concave (Fig. 9 ). The mandibular condyle sits posteriorly below the coronoid process at a nearly 45° angle. The angular process is enlarged, thick, long, and triangulate.

As with other Mesechinus species, except M. wangi which has an additional M4, the dental formula of the new species is I 3/2, C1/1, P 3/2, M 3/3 ( × 2) = 36. The I1 is enlarged, I2 is much smaller than I1 and I3, and I3 has two roots. P2 also has two roots which are not completely fused. P3 is small (smaller than P2) and has a vestigial protocone. M1 is slightly larger than M2, and M3 is reduced.

Comparison.

The hedgehogs from China’s Anhui and Zhejiang provinces can be easily classified as Mesechinus based on the following morphological characteristics: the absence of pure white spines; relatively small ears, almost similar in length to the surrounding spines; no bare part on the forehead nor at the top of the forehead which divides the spines on the head into two halves; and a U-shaped suprameatal fossa.

Among the Mesechinus species, M. orientalis sp. nov. is morphologically most similar to M. hughi. However, the new species can be distinguished by many characters. Mesechinus orientalis sp. nov. has the shortest spines in the genus (18-20 mm), shorter than those in M. hughi (22-24 mm). The parietal is relatively higher than the frontals in the new species, whereas the frontals are relatively higher than parietals in M. hughi . P2 has two roots which are not completely fused in M. orientalis sp. nov., while in M. hughi P2 the two roots are well fused. The P3 protocone is vestigial in the new species but well developed in M. hughi . The posterior palatal spine is vestigial, and the suprameatal fossa is moderately developed in the new species, which differs from the well-developed posterior palatal spine and shallow suprameatal fossa in M. hughi. In addition, the MTW and BM1 of the new species are significantly greater than those of M. hughi (P <0.01).

Mesechinus orientalis sp. nov. (HB = 188.83 mm ± 8.13; GLS = 49.95 mm ± 1.69) is distinguishable from M. dauuricus (HB = 373.91 mm ± 21.35; GLS = 55.18 mm ± 3.07), M. miodon (HB = 205 mm ± 23.53; GLS = 54.10 mm ± 2.10), and M. wangi (HB = 208.75 mm ± 21.90; GLS = 54.75 mm ± 0.70) by its smaller size. The spines of the new species are much shorter (18-20 mm) than those of M. dauuricus (21-24 mm), M. miodon (~26 mm), and M. wangi (21-24 mm). The spines of M. orientalis sp. nov. have four-colour rings similar to those of M. dauuricus and M. hughi , but they differ from M. miodon and M. wangi . P3 of the new species is much smaller than P2, which differs from M. dauuricus , in which P3 is of equal size to P2. The parietal is relatively higher than the frontals in M. orientalis sp. nov., which differs from M. wangi . Additionally, the presence of M 4 in M. wangi is unique in the genus, which easily distinguishes it from other species.

Distribution and habitat.

Mesechinus orientalis sp. nov. is currently known from southern Anhui (Xuancheng and Huangshan) and northwestern Zhejiang (Anji, Changxing, Deqing, Yuhang, Linan, Chunan), both in eastern China. Most specimens were collected in scrubland and subtropical broad-leaf evergreen forests at elevations from 30 to 700 m a.s.l.

Figures

Figure 4. Ventral and lateral views of left upper toothrow of M. orientalis sp. nov. A, C, B, D M. hughi. The arrows point at the root of P 2 (A, B), and the protocone of P 3 (C, D).

Figure 8. External morphs and spines of Mesechinus orientalis sp. nov. A male specimen (XC 2205001) B female specimen (XC 2205005).

Figure 9. Dorsal ventral and lateral views of skull and mandible of Mesechinus species A M. orientalis sp. nov. (holotype XC 23001) B M. hughi (KIZ 027029) C M. dauuricus (KIZ 027005) D M. miodon (holotype BM 9.1.1.9) E M. wangi (holotype KIZ 022028).