Urotrichini are Japanese and American shrew-moles belonging to the Old World Moles and Relatives

Talpinae

The subfamily Talpinae, sometimes called "Old World moles" or "Old World moles and relatives", is one of three subfamilies of the mole family Talpidae, the others being the Scalopinae, or New World moles, and the Uropsilinae, or shrew-like moles....

 branch of the mole family

Talpidae

The family Talpidae includes the moles, shrew moles, desmans, and other intermediate forms of small insectivorous mammals of the order Soricomorpha...

. There are only three species, each of which represents its own genus. The name "Shrew-moles" refers to their morphological resemblance to shrews, while generally being thought of as True Moles. The species are the Japanese Shrew Mole

Japanese Shrew Mole

The Japanese Shrew Mole or Himizu is a species of mammal in the Talpidae family. It is endemic to Japan. It is one of three Urotrichini and it is the only species in the genus Urotrichus.-References:...

, True's Shrew Mole

True's Shrew Mole

True's Shrew Mole is a species of mammal in the Talpidae family. It is endemic to Japan.It is the only species in the genus Dymecodon . It was recently removed from the genus Urotrichus.-References:...

 and American Shrew Mole.

In Japan, the word "Himizu" (ヒミズ) may to refer to both to the Japanese Shrew Mole

Japanese Shrew Mole

The Japanese Shrew Mole or Himizu is a species of mammal in the Talpidae family. It is endemic to Japan. It is one of three Urotrichini and it is the only species in the genus Urotrichus.-References:...

 in particular or Urotrichini in general; when True's Shrew Mole

True's Shrew Mole

True's Shrew Mole is a species of mammal in the Talpidae family. It is endemic to Japan.It is the only species in the genus Dymecodon . It was recently removed from the genus Urotrichus.-References:...

 is distinguished from the general Himizu forms, the feminine diminutive word "Hime" is added to refer to the smaller size of that species. Although they are common in Japan, their alpine habitats, small size, and secretive lifestyle makes them generally unknown except among some mountain people and researchers.

Morphology/Ecological Niche

Urotrichini paws are smaller and more downward- and backward-facing than the out-and-to-the-side orientation of the paws of classic moles, although not so much as in shrews. The limbs protrude slightly down and away from the body, as opposed to being invisibly retracted into the body with paws springing from just behind the head, as with moles. As such, Urotrichini are less well adapted than moles to forward burrowing, but better adapted to digging through the softer surface debris, leaf litter, and topsoils of alpine forest surfaces.

Nocturnality

Unlike true moles, Urotrichini are not equally active day and night. Himizu spend a large part of their days sleeping in specially excavated deep subsoil burrows.

Position within the Talpidae family

Urotrichini are relatively more closely related to The American Shrew Mole than they are either Taiwanese and mainland Asian "shrew moles"

Uropsilinae

The Uropsilinae are shrew-like members of the mole family endemic to the forested, high-alpine region bordering China, Myanmar, and Vietnam. They possess a long snout, a long slender tail, external ears, and small forefeet unspecialized for burrowing...

 or New World Moles

Scalopinae

The Scalopinae, or New World moles, are one of three subfamilies of the Talpidae family, which consists of moles and mole-like animals; the other two subfamilies being the Old World Talpids and the Chinese Shrew-like Moles...

. They and the American Shrew Mole are both members wholly within the main sub-family of Old World Moles

Talpinae

The subfamily Talpinae, sometimes called "Old World moles" or "Old World moles and relatives", is one of three subfamilies of the mole family Talpidae, the others being the Scalopinae, or New World moles, and the Uropsilinae, or shrew-like moles....

, which includes both moles

Mole (animal)

Moles are small cylindrical mammals adapted to a subterranean lifestyle. They have velvety fur; tiny or invisible ears and eyes; and short, powerful limbs with large paws oriented for digging. The term is especially and most properly used for the true moles, those of the Talpidae family in the...

 and desman

Desman

The desmans or tribe Desmanini are one of several tribes of the mole family Talpidae.This tribe consists of two species of semiaquatic insectivores found in Europe; one in Russia and the other in the Pyrenees. Both species are considered to be vulnerable...

s. The chiefly Chinese Uropsilinae

Uropsilinae

The Uropsilinae are shrew-like members of the mole family endemic to the forested, high-alpine region bordering China, Myanmar, and Vietnam. They possess a long snout, a long slender tail, external ears, and small forefeet unspecialized for burrowing...

shrew moles, despite having been called "Shrew-moles", are morphologically and genetically quite different, and so form a sub-family of their own, and, indeed, are now referred to in English as "shrew-like moles".

The taxonomy of this group has changed. Both species had been thought of as one genus, the Urotricus. More recently, it was decided that a new genus, Dymecodon, be created within the Urotrichini to reflect significant morphological differences.

Distribution

The fluctuating borders between Urotrichini species in Japan have been the subject of study. Dymecon pillarists is found only at higher altitudes, possibly due to soil conditions. The larger Urotricus talpoides dominates richer lowland areas, displacing D. pillarists to the poorer soils on the steeper slopes of higher altitudes. Maps of these fluctuating boundaries show a sea of Japanese Shrew Mole territory dotted with islands of True's Shew mole on the steeper areas. This results in isolation of breeding populations of D. pillarists and notable sub-speciation among the Himizu Hime which is not found among the standard Japanese Shrew Moles.