Dymecodon pilirostris, True, 1886

Russell A. Mittermeier & Don E. Wilson, 2018, Talpidae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 52-619 : 602-603

17.

True’s Shrew Mole

Dymecodon pilirostris

French: Taupe de True / German: True-Spitzmull / Spanish: Topo musarana de True

Other common names: Lesser Japanese Shrew Mole

Taxonomy. Dymecodon pilirostris True, 1886 ,

“Yenosima [= Enoshima], at the mouth of the Bay Yeddo [= Tokyo Bay],”

Honshu, Japan. Dymecodon pilirostris is the only extant species of Dymecodon . Molecular and morphological data retrieved a monophyletic clade formed by D. pilirostris and Urotrichus talpoides , but the two species clearly belong to distinct genera. Monotypic.

Distribution. Japan (Honshu, Shikoku, and Kyushu); distribution in C Honshu is rather continuous, while N & W distribution is patchy and isolated due to mountainous topography.

Descriptive notes. Head-body 70-84 mm, tail 32-44 mm, hindfoot 12:8-15-2 mm; weight 8-14-5 g. Tail of True’s Shrew Mole is 43-60% of head-body length. Snout is very long, slender, and hairy. Auricles are lacking. Forefeet are only slightly broadened, with somewhat flattened and nearly straight claws. Tail is covered with short hairs. Dorsum is grayish black to blackish brown; venteris paler. Dental formula is 13/2, C 1/1, P 3/3, M 3/3 (x2) = 38, but alternative formula of 1 2/1,C1/1,P4/4,M 3/3 (x2) = 38 was proposed based on position of maxilloincisive suture and fifth monophyodont teeth. Chromosomal complement has 2n = 34 and FNa = 62.

Habitat. Forests and grasslands in high mountains, generally subalpine and alpine zones usually at elevations above 1000 m. True’s Shrew Mole is parapatric and sympatric with the Japanese Shrew Mole ( Urotrichus talpoides ), but it generally occurs at higher elevations.

Food and Feeding. True’s Shrew Mole eats insects, earthworms (Oligochaeta), small centipedes, spiders, and other small invertebrates.

Breeding. Annual breeding season of True’s Shrew Mole seems to occur once in spring. Breeding males caught in April-June had testis lengths of ¢.8 mm, and in May-July, pregnant females had 3-6 embryos. There are six mammae: one pectoral, 0-1 abdominal, and 1-2 inguinal pairs. Based on determination of three age classes with tooth wear, longevity is estimated at c.2 years.

Activity patterns. True’s Shrew Mole is semi-fossorial but active aboveground.

Movements, Home range and Social organization. Density of True’s Shrew Mole is 5-14 ind/ha in subalpine coniferous forest. Home ranges are 25-26 m long in coniferous forest in central Honshu.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Abe (1967 1968), Kawada & Obara (1999), Motokawa (2004), Ohdachi et al. (2015), Shinohara et al. (2003).

Figures

1. Equivalent-teeth Shrew Mole (Uropsilus aequodonenia), 2. Anderson’s Shrew Mole (Uropsilus andersont), 3. Gracile Shrew Mole (Uropsilus gracilis), 4. Inquisitive Shrew Mole (Uropsilus investigator), 5. Chinese Shrew Mole (Uropsilus soricipes), 6. Snow Mountain Shrew Mole (Uropsilus nivatus), 7. Black-backed Shrew Mole (Uropsilus atronates), 8. Gansu Mole (Scapanulus oweni), 9. Hairy-tailed Mole (Parascalops breweri), 10. Coast Mole (Scapanus orarius), 11. Townsend’s Mole (Scapanus townsend), 12. Broad-footed Mole (Scapanus latimanus), 13. Mexican Mole (Scapanus anthonyi), 14. Eastern Mole (Scalopus aquaticus), 15. Long-tailed Mole (Scaptonyx fusicauda), 16. Japanese Shrew Mole (Urotrichus talpoides), 17. True’s Shrew Mole (Dymecodon pilirostris), 18. American Shrew Mole (Neurotrichus gibbsi), 19. Star-nosed Mole (Condylura cristata), 20. Russian Desman (Desmana moschata), 21. Pyrenean Desman (Galemys pyrenaicus)

Distribution. Japan (Honshu, Shikoku, and Kyushu); distribution in C Honshu is rather continuous, while N & W distribution is patchy and isolated due to mountainous topography.