Shin-ichiro Kawada

Karyosystematic Analysis of Japanese Talpine Moles in the Genera Euroscaptor and Mogera (Insectivora, Talpidae)

Abstract A detailed analysis was done on the karyotypes of four species of mole in the genera Euroscaptor and Mogera using a G-banding technique. All four species examined had a chromosome number of 2n = 36, as reported previously. Euroscaptor mizura and M. wogura from Aichi Prefecture had almost the same chromosome constitution and G-banding patterns. These common karyotypes were considered to be equivalent to the hypothetical ancestral karyotype of Mogera, since two distinct genera derived from an ancestor share G-banding homologies. According to this hypothesis, the karyotype of M. imaizumii might have been derived from the ancestral karyotype through pericentric inversion in one pair of acrocentrics, chromosome 11. Two geographically isolated populations of M. tokudae had different karyotypes: the Echigo population had the same karyotype as M. imaizumii, whereas the Sado population had a derivative karyotype that was able to be explained by pericentric inversions in three pairs of acrocentrics, remaining chromosome 11 as subtelocentric. Mogera wogura from South Korea differed considerably in terms of chromosome constitution from the Japanese population of M. wogura. However, we deduced that pericentric and paracentric inversions in four pairs of acrocentrics would explain the karyotype differences between the Japanese and Korean populations. Furthermore, from the morphology of chromosome 11, we can conclude that the Korean mole was derived from primitive M. wogura through four inversions, quite separately from the lineage of M. imaizumii and M. tokudae. Thus, inversion rearrangements appear to have played a major role in the chromosomal evolution of Japanese talpine moles.

Revision of the mole genus Mogera (Mammalia: Lipotyphla: Talpidae) from Taiwan

Abstract We surveyed the central mountains and southeastern region of Taiwan and collected 11 specimens of a new species of mole, genus Mogera. The specimens were characterized by a small body size, dark fur, a protruding snout, and a long tail; these characteristics are distinct from those of the Taiwanese lowland mole, M. insularis (Swinhoe, 1862). A phylogenetic study of morphological, karyological and molecular characters revealed that Taiwanese moles should be classified as two distinctive species: M. insularis from the northern and western lowlands and the new species from the central mountains and the east and south of Taiwan. The skull of the new species was slender and delicate compared to that of M. insularis. Although the karyotypes of two species were identical, the genetic distance between them was sufficient to justify considering each as a separate species. Here, we present a detailed specific description of the new species and discuss the relationship between this species and M. insularis based on ecological characteristics and geographic distributions.

Three-Dimensional CT Examination of the Mastication System in the Giant Anteater

Abstract The gross anatomy of the mastication system of the giant anteater (Myrmecophaga tridactyla) was examined by means of three-dimensional image analysis. The anteater rotates the mandibles medially and laterally to control its tongue when it is elongated and to house it when it is relaxed. Three-dimensional CT image analysis demonstrated that the shape and size of the oral cavity changes drastically when the mandibles are rotated. The oral cavity expands bilaterally when the dorsal part of the mandibles bend medially. Macroscopic observations and muscle-weight data supported the observation that the superficial temporal and medial pterygoid muscles act as the main medial and lateral rotators of the mandible, respectively. The low height of the mandibular ramus and the incomplete zygomatic arch in this species represent adaptations for the rotational movement of the mandibles, since they both contribute to the medially oriented transmission of force from the temporal muscles and to preventing collision between the mandibles and the cranium during the rotational movement.

Three-Dimensional Reconstruction of the Xenarthrous Process of the Thoracic and Lumber Vertebrae in the Giant Anteater

Abstract. The presacral vertebra of anteaters was examined by three-dimensional CT image analysis of the xenarthrous processes peculiar to the Order Xenarthra. The anteater is equipped with two following articulations in addition to the normal zygapophysial articulation. The dorsal xenarthrous process of the former vertebra articulates to the ventral area of the base of the mammillary process in the later vertebra. The pocket-like structure in the ventral area of the mammillary process receives the dorsal and ventral xenarthrous processes of the former vertebra. The complicated articulations do not obstruct the ability of the giant anteater to flex dorsally and laterally, however aids flexibility and strengthens the caudal thoracic and lumber regions of the animal. The xenarthrous processes and articulations may function as a supporter of the body weight during the bipedal standing posture when the anteater destroys the nests of ants and termites and protects itself from the enemies.

Molecular phylogeny of East and Southeast Asian fossorial moles (Lipotyphla, Talpidae)

Abstract The diversity of fossorial moles in East and Southeast Asia is contained in the 2 species-rich genera Mogera (8 species) and Euroscaptor (8 or more species), and the 3 monospecific genera Scapanulus, Scaptochirus, and Parascaptor. To better understand the evolution and biogeography of these fossorial moles, we conducted molecular phylogenetic analyses using mitochondrial cytochrome-b (Cytb; 1,140 base pairs [bp]) and 12S rRNA (approximately 830 bp) and nuclear recombination activating gene 1 (Rag1; 1,010 bp) gene sequences from 5 species of Euroscaptor, 6 of Mogera, and the single species of Scaptochirus. Phylogenetic estimates revealed 5 distinct lineages of East and Southeast Asian fossorial moles: Mogera, Scaptochirus, Euroscaptor mizura, E. parvidens, and E. malayana–E. klossi–E. longirostris. Our results support the monophyly of Mogera but not Euroscaptor, indicating a need for taxonomic revision of the latter genus. We hypothesize that Mogera originated in the central portion of its range and then dispersed to peripheral islands, such as Taiwan and the Japanese Islands. The fragmented distribution of Southeast Asian Euroscaptor presumably arose from habitat competition (invasion) from Mogera species, long-range dispersal, vicariance events, or a combination of these, explaining the high species richness of fossorial moles in this region.

Phylogenetic relationships of the short-faced mole, Scaptochirus moschatus (Mammalia: Eulipotyphla), among Eurasian fossorial moles, as inferred from mitochondrial and nuclear gene sequences

MSJ ammal Study 1343-4152 the Mammalogical Society of Japan Short co munication Phylogenetic relationships of the short-faced mole, Scaptochirus moschatus (Mammalia: Eulipotyphla), among Eurasian fossorial moles, as inferred from mitochondrial and nuclear gene sequences Phylogenetic position of short-faced mole Akio Shinohara*, Shin-ichiro Kawada, Masashi Harada, Kazuhiro Koyasu, Sen-ichi Oda and Hitoshi Suzuki

A new species of mole of the genus Euroscaptor (Soricomorpha, Talpidae) from northern Vietnam

Abstract A new species of talpine mole from northern Vietnam is described and compared with other species of the genus Euroscaptor. This small mole was assigned to the genus Euroscaptor on the basis of its dental formula, but it also shows unique morphological and karyological characteristics. The new species is externally similar to E. parvidens from southern Vietnam, possessing warty protuberances on the muzzle not seen in other members of this genus. The tail of the new species is much shorter than in E. parvidens and E. malayana, both known to have short tails. The tail is not visible under the fur in the dorsal view, giving it an almost tailless appearance. The skull of the new species is similar to that of E. longirostris, but the palate is characteristically wider. The molars of the upper jaw are of a simple triangular shape, and there is no hypoconulid in the lower molars. The diploid number of the new species was determined to be 2n  =  38, which is a new karyotype for this genus. This mole inhabits the lower elevational areas of northern Vietnam and is partially peripatric with E. longirostris in the type locality. Because of the distribution of another taxon in northern Vietnam, Mogera latouchei, the ecological relationships among 4 species of Vietnamese moles also is discussed.

The historical notes and taxonomic problems of East Asian moles, Euroscaptor, Parascaptor and Scaptochirus, of continental Asia (Insectivora, Talpidae)

ABSTRACT The taxonomy of the East Asian moles of genera Euroscaptor, Parascaptor and Scaptochirus, distributing in the Himalayas to China were controversial both in the generic and specific levels. These genera were named as more than ten species since the beginning of the description by Brian Houghton Hodgson in 1841. Several explorers had the expedition to this area and brought the specimens of these moles to European and American Museums and named them. One of the purpose of this paper is to review the historical note on the discoveries of Asian mole species as the compass to situate the taxonomic problem of these moles. As a matter of taxonomic evaluation, the problem of the usage of dental formula as the generic diagnosis is discussed in the reference of the examples of recent taxonomic works. Distribution of these East Asian talpids are scattered in the mountain regions like plot according from the collecting records by museums. Current museum collections are not enough to examine their local and individual variations. Therefore, active collecting in the future works will enable the reevaluation of taxonomic and phylogenetic relationships through comprehensive studies of morphology, karyology and molecular phylogeny.

The Brachial Plexus Adapted to the Semi-Elongated Neck in the Okapi

Abstract. The brachial plexus of the okapi showed the evolutionarily intermediate status between the underived ruminants and the giraffe with elongated neck. Whereas the C6 was the thinnest among the roots of the brachial plexus, the C7, C8 and T1 were much thicker in the okapi. From the data we concluded that the okapi was equipped with the intermediate characteristics of the disappearing C6. Although the nerve of the C6 should be elongated in accordance with the long neck in the Giraffidae, the extraordinary elongation of the C6 may have no advantages in the function of the innervations. In the okapi, therefore, we suggest that the function of the C6 has been mainly replaced with that of C7.

KARYOTYPE EVOLUTION OF SHREW MOLES (SORICOMORPHA: TALPIDAE)

Abstract The Chinese long-tailed mole (Scaptonyx fusicaudus) closely resembles American (Neurotrichus gibbsii) and Japanese (Dymecodon pilirostris and Urotrichus talpoides) shrew moles in size, appearance, and ecological habits, yet it has traditionally been classified either together with (viz subfamily Urotrichinae) or separately (tribe Scaptonychini) from the latter genera (tribe Urotrichini sensu lato). We explored the merit of these competing hypotheses by comparing the differentially stained karyotypes of S. fusicaudus and N. gibbsii with those previously reported for both Japanese taxa. With few exceptions, diploid chromosome number (2n = 34), fundamental autosomal number (FNa = 64), relative size, and G-banding pattern of S. fusicaudus were indistinguishable from those of D. pilirostris and U. talpoides. In fact, only chromosome 15 differed significantly between these species, being acrocentric in D. pilirostris, subtelocentric in U. talpoides, and metacentric in S. fusicaudus. This striking similarity is difficult to envisage except in light of a shared common ancestry, and is indicative of an exceptionally low rate of chromosomal evolution among these genera. Conversely, the karyotype of N. gibbsii deviates markedly in diploid chromosome and fundamental autosomal number (2n = 38 and FNa = 72, respectively), morphology, and G-banding pattern from those of Scaptonyx and the Japanese shrew moles. These differences cannot be explained by simple chromosomal rearrangements, and suggest that rapid chromosomal reorganization occurred in the karyotype evolution of this species, possibly due to founder or bottleneck events.