Tamiops minshanica, Liu & Tang & Murphy & Liu & Wang & Wan & Liao & Tang & Qing & Chen & Li, 2022

Liu, Shaoying, Tang, Mingkun, Murphy, Robert W., Liu, Yinxun, Wang, Xuming, Wan, Tao, Liao, Rui, Tang, Keyi, Qing, Jiao, Chen, Shunde & Li, Song, 2022, A new species of Tamiops (Rodentia, Sciuridae) from Sichuan, China, Zootaxa 5116 (3), pp. 301-333 : 318-320

Tamiops minshanica sp. nov. Liu SY, Tang MK, Murphy RW, Chen SD et Li S.

Min Mountain striped squirrel

Holotype. Adult male, SAF 181596 , collected by Rui Liao on 29 October 2018 (field number WL 18668, winter pelage). It was caught with a snap trap (Jiangxi Mouse Devices Factory) on the ground near a stream. The specimen is prepared as a skin with cleaned skull, baculum, and muscle tissue, and is deposited at the Sichuan Academy of Forestry.

Measurements of Holotype. Weight 95 g; HBL 140 mm; TL 105 mm; HFL 32 mm; EL 16 mm; GLS 37.15 mm; CBL 33.45 mm; BL 30.99 mm; ZOB 22.24 mm; IOB 13.12 mm; NL 11.19 mm; PL 15.59 mm; ABL 8.54 mm; ABB 6.23 mm; UTR 16.97 mm; LTR 15.64 mm; LMXTR 6.71 mm; LMDTR 6.41 mm; ML 25.34 mm; MH 11.91 mm.

Type locality. Wanglang National Natural Reserve , Pingwu County, Mianyang, Sichuan, China. 32.99600°N, 104.01924°E, 2880 m.

Paratypes. Three adult specimens, SAF 181270 (WL 18342), male, collected by Rui Liao and Xuming Wang on 26 August 2018 (summer pelage), 32.94745N, 104.13294E, 2528m; SAF 181491 (WL 18563), female, collected by Rui Liao and Xuming Wang on 28 October 2018 (winter pelage), 32.95971N, 103.99911E, 3000m; and SAF 181730 (WL 18802), male, collected by Rui Liao and Xuming Wang on 3 November 2018 (winter pelage), 32.97660N, 104.08069E, 2600m. Male specimens have undamaged skins, skulls, and glans penes. All paratypes were collected in Wanglang National Natural Reserve .

Measurements of paratypes. Weight 73–85 g; HBL 122–136 mm; TL 95–105 mm; HFL 32–33 mm; EL 16–18 mm; GLS 36.34–37.28 mm; CBL 32.69–33.38 mm; BL 30.20–30.79 mm; ZOB 20.53–21.59 mm; IOB 12.69–12.98 mm; NL 10.68–11.56 mm; PL 14.64–15.52 mm; ABL 8.49–8.78 mm; ABB 6.35–6.36 mm; UTR 16.66–16.81 mm; LTR 15.32–15.60 mm; LMXTR 6.63–6.99 mm; LMDTR 6.63–6.79 mm; ML 25.18–25.25 mm; MH 11.29–12.02 mm.

Distribution. To date, the species is known only from the Wanglang National Natural Reserve, Pingwu County, Sichuan, China.

Etymology. The name is derived from Minshan (Min Mountain) where the Wanglang National Natural Reserve is located. This mountain range is a part of the Hengduan Mountains, known for a very high diversity of elevations and habitats.

Nomenclatural statement. A LSID number was obtained for the new species ( Tamiops minshanica sp. nov.): 5BE17563-1731-4805-A90F-C85CCCF7E96B.

Diagnosis. The body size of T. minshanica sp. nov. falls intermediate between T. swinhoei and T. maritimus . The new species is distinguishable from other members of the genus by its back with obvious brown tinge, forehead and top of head bright brown, belly rusty, back of ear with a pure white tuft, summer pelage ( Figure 9 ) with 5 black stripes, 3 middle stripes obviously black, outmost pair of stripes vague, only slightly darker than back fur, winter pelage with 1 middorsal black stripe, 4 light stripes identically bright brown in all seasons, and auditory bulla very large, exceeding 8.5 mm in length.

Description. The holotype collected in late October exhibits a winter pelage and the paratype (WL 18342) shows a summer pelage. Summer pelage ( Fig. 9 ) displays 5 black stripes on the back, outermost pair stripes vague, stripes originating on nape 20 mm after ear, middle stripe reaching base of tail, lateral pairs of black stripes not reaching base of tail, ending 13mm from it, middle part of black stripes the widest, about 6mm wide, anterior and proximal parts narrower, about 4mm. On the back, four light stripes identically bright brown, outer pair 6 mm wide, slightly more yellow-white and broader than inner pair light stripes (4 mm wide), forehead and top of the head bright brown, middle of snout with 6mm black longitudinal stripe, cheek stripe yellow brown line, indistinct boundary reaching from the rostrum over whisker patch, beneath eye and ear, becoming broader at side of neck and interrupted at shoulder, not connecting with outer light line, iris yellow-brown, pure white tuft behind ear, or the base with a small proportion of black-gray. Fur on back of ear black and inside ear yellow-brown, body side, upper surface of tail, shoulder, and hip grey-brown, ventral tail rusty, hair on forelimbs yellow-brown, hindlimb pelage gray-brown, 5 palmar pads and 6 plantar pads, claws strong, and middle toe claw about 4 mm. Based on one female paratype, T. minshanica sp. nov. has 6 mammae consisting of 1 pectoral and 2 inguinal pairs.

The winter pelage differs from the summer coat: fur denser and softer, middorsal line black, lateral pair black lines becoming gray-brown color, stripes starting 30mm behind ear, whole back lighter with remarkable yellowbrown, claws longer, with middle toe claw about 6 mm.

Skull and mandible of T. minshanica sp. nov. are comparatively sturdy ( Fig. 6 , A 1–A 4 ). The dorsal profile is arcuate, and the braincase rounded. Rostrum is relatively short, steeply narrowing. Nasals are broader anteriorly, narrower posteriorly, but sides of the posterior third are in parallel. The posterior margin of nasals is plane, becoming straight at suture with maxilla. Frontal is relatively long, nearly 40% of skull length. Suture between frontal and parietal is linear or slightly V-shaped. Interparietal and parietal suture is ankylotic in adults but the outline of the interparietal suture is unclear. Short supraorbital projection is extending backward. A ridge exists behind temporal and above auditory bulla. Squamosals, frontals, and parietals are smooth without ridges. Zygomatic arches are relatively robust. Auditory bullae are large, average 8.7 mm long, 6.3 mm wide. Only 1 transbullar septum exists in auditory bullae. Incisory foramen is comparatively short and narrow, 2 mm long, 0.5 mm wide. Posterior palate is plane, pterygoids lamellar.

Upper incisors are narrow, exhibiting orange enamel. Two upper premolars and 3 upper molars are cream-white ( Fig. 6 , A 5 ). The first upper premolar is very small and cylindrical, closing to lingual side whereas second upper premolar and three upper molars have 3 outer and 3 inner main cusps ( Fig.6 , A 5 , left), among which the middle one (protoconid) is relatively larger. Labial cusps (anteroconule, paracone, and metacone) are relatively small, worn off in the older individual.

Lower incisors are relatively long, about 17.35 mm, inset 12.90 mm, about 66% of the whole mandible length. Lower premolars are almost dimetric, 2 inner and outer prongs, worn in adults. Three lower molars with similar morphology, third largest. Three cusps on the lingual side, middle one (mesoconid) smallest, anterior one (metaconid) largest. Among three cusps on the labial side, anterior-most (anteroconulid) is vestigial compared to two posterior cusps (protoconid and hypoconid) of the same size ( Fig. 6 , A 5 , right).

Outline of glans penis of T. minshanica sp. nov. ( Fig. 5 , G) is akin to the head of a sturgeon characterized by long snout, high head, ventral saw-like structure (“blade” sensu Pocock 1923) with 20 ridges. Two semilunar lappets appear around the urethral orifice on the left side. Baculum of the Min Mountain striped squirrel is also unique by having 2 shafts ( Fig. 5 , H). Its main shaft is arciform, as the front quarter is bulged while the corpus cavernosum wraps its posterior part. Ventral blade is hacksaw-like with about 20 ridges.

Reproduction. The 4 adult type specimens studied were all reproductively inactive. 1 male paratype (WL 18342) collected in August did not demonstrate orchidoptosis, whereas testes of 2 males (WL 18668 and WL 18802) collected in late October and beginning of November including the holotype were also abdominal. The only female collected in late October (WL 18563) was not pregnant.

Habitat. This new species is expected to occur only in original coniferous forest, broad-leaved forest, and mixed coniferous and broad-leaved forest. Elevation of the collected specimens ranges from 2530 m to 3004 m. The four specimens were collected in the moist, riparian habitat near a stream, possibly while going for drinking. The vegetation at the type locality consists of original fir and spruce forest at 70% of coverage, where height of trees reaches 30 meters on average. Understory consists of shrubs, average 2.0 meters high, at 40% of coverage along with grasses, 0.3 meters high, at 20% of coverage. The thickness of the humus layer is 20 cm.

Figures

FIGURE 1. Distribution map of nominated taxa of Tamiops. 1–4 specimens of Tamiops sp.; 5–36, nominated taxa of Tamiops. The numbers correspond to Table 1.

FIGURE 4. Skull comparison of Tamiops sp. (voucher number: WL18668), T. swinhoei swinhoei (voucher number: SAF- XBD19062), T. maritimus hainanus (voucher number: KIZ-12976), T. mcclellandii collinus (voucher number: KIZ-551), and T. rodolphii (voucher number: USNM-2337)*. Ventral view shows the proportion of the length of auditory bulla to the greatest length of skull (GLS); dorsal view shows the proportion of nasal bone to GLS, and the proportion of middle width of rostrum to zygomatic breadth (ZOB). *: Measurements of GLS, NL, and ABL for T. rodolphii from Kloss (1916).

FIGURE 6. Cranial and dental of Tamiops sp. and comparison of teeth among four existing species of Tamiops and Tamiops sp. A1: ventral view of Tamiops sp. (voucher number: SAF- JJSA422; A2-A5, the same specimen) skull; A2: lateral view of Tamiops sp. skull; A3: dorsal view of Tamiops sp. skull; A4: mandible of Tamiops sp. (lateral view); A5: cheek teethrow of Tamiops sp. (Left: upper toothrow, lingual side on left; right: lower cheek toothrow, lingual side on right); B: toothrow of T. swinhoei (voucher number: SAF- JJSA422); C: toothrow of T. maritimus (voucher number: KIZ-12976); D: toothrow of T. mcclellandii (voucher number: KIZ-551); E: toothrow of T. rodolphii (voucher number: USNM-2337).

FIGURE 9. Summer pelage of Tamiops minshanica sp. nov.

FIGURE5. Comparison of glans penis and baculum between Tamiops sp.,T.swinhoei swinhoei, T.maritimus, andT.mcclellandii. A–B: Tamiops s. swinhoei (voucher number: SFA-XBD19196); C–D: Tamiops maritimus (voucher number: SAF-2001); E-F: Tamiops mcclellandii (voucher number: KIZ-76296); G-H: Tamiops sp. (voucher number: SAF-WL18668). 1: Body of penis; 2: glans; 3: urethral orifice; 4: groove of glans (only occurring in Tamiops s. swinhoei); 5: prepuce; 6: corpora cavernosa penis; 7: cavernous body of urethra; 8: baculum main shaft; 9: baculum blade shaft; 10: semilunar urethral lappet (only occurring in new species).