Urotrichus Research Articles

Bone microstructure as an indicator of digging ability in moles (Talpidae, Eulipotyphla).

Talpid moles (Talpidae, Eulipotyphla) are mammals highly specialised in burrowing using their forelimbs. Fossoriality has allowed moles to expand their ecological niche by enabling access to subterranean resources and spaces. This specialisation in burrowing has led to adaptations in the forelimb bones of moles for humeral rotation digging, a distinctive strategy unparalleled among other diggers. While bone robustness has been examined in moles through external morphology, the adaptation of bone microstructure to digging strategy remains unclear. Based on two assumptions, (1) the humerus of moles is subjected to a torsional load due to humeral rotation digging, and (2) the magnitude of torsional load correlates with the compactness of the substrate in which the individuals can dig, we hypothesised that humeral rotation digging influences bone microstructure. Comparative analyses of transverse sections from the humeri and femora of three mole species (Mogera imaizumii, Mogera wogura and Urotrichus talpoides; Talpidae) and an outgroup eulipotyphlan (Suncus murinus; Soricidae) revealed that (1) vascular canals distributed in the humeri of moles align more predominantly circumferential along the bone walls, indicating an adaptation to the torsion generated by humeral rotation digging, and (2) the laminarity of vascular canals, particularly in Mogera species compared with Urotrichus, potentially reflects differences in the magnitude of load due to substrate compactness during digging. The aligned vascular canals are distinctive traits not observed in mammals employing other digging strategies. This suggests that vascular canal laminarity can be an indicator of not only humeral rotation digging in fossorial animals, but also the variation of eco-spaces in talpid species.

Reconsideration of the actual type locality of the lesser Japanese shrew-mole, Dymecodon pilirostris

Reconsideration of the actual type locality of the lesser Japanese shrew-mole, Dymecodon pilirostris

Chromosomal Evolution of the Talpinae.

In recent years, the number of mole species with species status confirmed by genetic methods has been continuously increasing. Unfortunately, cytogenetic data are not yet available for all species. Here, for the first time, a GTG-banded karyotype of the small-toothed mole from Vietnam, Euroscaptor parvidens, a representative of the Eastern clade of the genus Euroscaptor, has been described. Through comparative analysis of available Euroscaptor (Euroscaptor parvidens, Euroscaptor klossi, and Euroscaptor malayana) and Oreoscaptor (Oreoscaptor mizura) karyotypes, we found cytogenetic signatures for each of the studied species. Zoo-FISH with sorted chromosomes of the Siberian mole (Talpa altaica) on chromosome sets of the small-toothed mole (E. parvidens), the small Japanese mole (Mogera imaizumii) from the closely related genus, and the Japanese shrew mole (Urotrichus talpoides) from the tribe Urotrichini made it possible to identify syntenic regions between these species. We propose a possible ancestral karyotype of the tribe and, based on it, traced the features of chromosomal rearrangements accompanying the divergence of moles. The low rates of chromosomal evolution within the species of the genus Talpa-T. altaica and T. europaea-and the high rates of karyotypic reshuffling within the Asian genera of the tribe were confirmed. The karyotype of the Japanese mountain mole O. mizura seems to be the most conserved among the Asian moles. The most frequently occurring types of chromosomal rearrangements in moles are the pericentric inversions and amplification of heterochromatin. The pericentric inversions on four pairs of autosomes are shared between the closely related genera Euroscaptor, Oreoscaptor, and Mogera, while many more apomorphic rearrangements have occurred in each lineage additionally. The highest rate of chromosomal changes, with five rearrangements occurring over approximately 7 million years, was recorded in the lineage of the small-toothed mole.

The complete mitochondrial genome of the long-tailed mole: Scaptonyx fusicaudus (Eulipotyphla, Talpidae)

The long-tailed mole (Scaptonyx fusicaudus) belongs to a monotypic genus within the family Talpidae. It is a small semi-fossorial mammal mostly distributed in south-western China. In this study, we obtained the complete mitochondrial genome of S. fusicaudus. The genome is a total of 16,602 bp in length, containing 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA) and 2 non-coding regions, with a base composition of 33.51% A, 28.73% T, 23.68% C and 14.08% G. The nucleotide sequence data of 13 protein-coding genes of S. fusicaudus and other 14 insectivora species were used to reconstruct a Bayesian phylogenetic tree. The tree shows that S. fusicaudus belongs to the subfamily Talpinae and is closely related to Urotrichus talpoides.

Geographic variation and biogeography of the greater Japanese shrew mole Urotrichus talpoides (Eulipotyphla: Talpidae)

The island rule has been generally studied as a morphological evolution between continents and islands. Recently, an evolution between islands of the larger main islands and smaller peripheral islands in Japan has been implied. This study revealed island–island biogeography and examined the island rule between islands. We studied the skull morphology of the greater Japanese shrew mole Urotrichus talpoides Temminck, 1841 (Eulipotyphla: Talpidae). Univariate and multivariate analyses were conducted on the basis of 20 measurements obtained from 296 specimens. Our results revealed morphological differences among islands, in the overall skull size, distance of the fourth premolar to the third molar in the upper and lower jaws (P4M3 and P4M3), and the slender–robust proportion of the rostrum and braincase. P4M3 and P4M3 were commonly larger in the peripheral island populations than in the main island populations. By contrast, the overall skull size and proportion of the rostrum and braincase diverged among the peripheral islands. Therefore, gigantism of P4M3 and P4M3 was suggested in the peripheral island populations, and the island rule was partially supported; however, the island–island morphological evolution should be considered to have a different direction from the island rule due to divergent morphology in small–large skull size and slender–robust proportion among peripheral island populations.

New Dental Anomalies in the Greater Japanese Shrew Mole Urotrichus talpoides (Eulipotyphla: Talpidae)

Dental anomalies in the greater Japanese shrew mole Urotrichus talpoides Temminck, 1841 (Eulipotyphla: Talpidae) were examined, based on 1001 specimens. We followed the dental formula of U. talpoides I 2/1, C 1/1, P 4/3, M 3/3 = 36, which is adopted by the most recent Japanese researchers, and found dental anomalies in 17 specimens involving 12 instances of absent tooth, four of extra tooth, and one of connate tooth. Of these, the following dental anomalies are reported in U. talpoides for the first time: extra tooth posterior to the upper canine (C1), extra tooth posterior to the upper second premolar (P2), extra teeth on the inner sides of the upper fourth premolars (P4), and connate tooth on the lower canine (C1). The most frequently observed dental anomaly was the absent tooth on C1 (52.9%), whereas the others were not common (< 11.8%). Our results indicate that dental anomalies in U. talpoides in Urotrichini possess the different pattern from those in species in Scalopini and Talpini. On the other hand, alternative hypothesis of dental formula I 3/2, C 1/1, P 3/2, M 3/3 = 36 explains the observed anomaly pattern in line with the general trend of dental anomalies in Talpini and Scalopini.

The variable heartbeat of Japanese moles (Mogera spp.).

This report demonstrates the variable cardiac rhythm in two species of subterranean mole, the large Japanese mole (Mogera wogura) and the lesser Japanese mole (Mogera imaizumii). The phenomenon was revealed using X-ray videos of M. wogura and investigated in detail using electrocardiogram (ECG) traces recorded with implanted electrodes in this species and M. imaizumii. Cessation of heartbeat and extended R-R intervals were observed in the ECGs from both species during short bouts of rest in wakeful specimens of both species under normoxic conditions at room temperature. The mean durations of R-R intervals were 288.8 ± 3.3ms for M. wogura and 191.9 ± 2.4ms for M. imaizumii. The cardiac rhythm in both species became more unstable and R-R interval was prolonged by 153.5% ± 17.7 after injection of a sympathetic blocker (propranolol), whereas the application of a parasympathetic blocker (atropine) resulted in increasing stability and a reduced interval between R wave peaks (R-R) 64.2% ± 4.8. ECGs of two related soricomorphs, the fossorial Japanese shrew-mole (Urotrichus talpoides) and surface-dwelling Japanese white-toothed shrew (Crocidura dsinezumi) were also recorded and compared for comparison. The heartbeats of these species were relatively stable compared with those of the subterranean moles. Our results indicated clear differences in the physiological cardiac features between the examined members of the Soricomorpha.

Concentration of radioactive materials in small mammals collected from a restricted area in Fukushima, Japan since 2012

AbstractFukushima Daiichi Nuclear Power Plant was struck by a huge earthquake and tsunami, which ultimately released a large amount of radioactive material owing to steam explosion in March 2011. This accident affected extensive area and resulted in soil contamination, which would prevail over a long period. The contaminants included various types of nuclear materials, among which cesium (134,137Cs) has a particularly long half‐life. Organisms living in the contaminated area are presumably exposed to radiation caused by the presence of these radioactive contaminants in their environment, in addition to internal exposure owing to the intake of these contaminants through the food web. The purpose of our data collection is to monitor accumulation of radioactive materials in small mammals for a long period and to predict its effects. Reasons for focusing on small mammals include: (a) mammals are the most sensitive to radiation, (b) small mammals have a smaller home range compared to large mammals; therefore, accumulation of radioactive materials in small mammals is considered to reflect the condition of the surrounding environment, and (c) among the small mammals, rodents are used as laboratory animals and provide a lot of information, from which we can expect to acquire much knowledge based on investigations. The dataset contains measurements of 134,137Cs and potassium (40K) concentrations in small terrestrial mammals collected in areas contaminated with radioactive contaminants from the Fukushima Daiichi Nuclear Power Plant accident. We established two fixed study sites and three temporary sites inside the zone from which humans were evacuated owing to high levels of radiation. Annual monitoring of Cs contamination in small mammals was started in 2012 at the fixed study sites. Until 2016, we collected 547 individuals of four species (Apodemus speciosus, Apodemus argenteus, Microtus montebelli and Urotrichus talpoides). Cs concentrations in each individual were measured using high‐purity germanium detectors against a ground body after removing the internal organs and the head. Our data provide valuable information about temporal changes in 134Cs and 137Cs concentrations in small mammals following the Fukushima Daiichi Nuclear Power Plant accident. The study is continuing and the present dataset will be updated in the future.

A histological study of tail width variation in the greater Japanese shrew-mole,Urotrichus talpoides

The greater Japanese shrew-mole, Urotrichus talpoides, has a wide and thick tail like a baseball bat with bristles like bottle brushes. It is known that not only length variations but also the width variations are observed in the tails of U. talpoides. To understand such width variations of the tail, we examined morphological and histological characteristics. The width variation was not related to the season when captured or aging, as indicated by the skull sizes. In addition, tail vertebra width was not correlated with tail width. On the other hand, according to histological observation of tail skin, the ratio of subcutaneous tissue/corium indicating the thickness of the subcutaneous tissue layer was positively correlated with the tail width (p < 0.05). The thickness of the subcutaneous tissue layer means that the rich adipose tissue and cells observed were unilocular, then identified as white adipose cells. It is well known that one of the functions of white adipose cells is to store excess energy as neutral fat. Thus, it is suggested that U. talpoides stores an energy source as adipose cells in the skin of the tail, demonstrating that tail width variations are caused by the thickness of the subcutaneous tissue layer.

Comparative Morphology of the Penis and Clitoris in Four Species of Moles (Talpidae).

The penile and clitoral anatomy of four species of Talpid moles (broad-footed, star-nosed, hairy-tailed, and Japanese shrew moles) were investigated to define penile and clitoral anatomy and to examine the relationship of the clitoral anatomy with the presence or absence of ovotestes. The ovotestis contains ovarian tissue and glandular tissue resembling fetal testicular tissue and can produce androgens. The ovotestis is present in star-nosed and hairy-tailed moles, but not in broad-footed and Japanese shrew moles. Using histology, three-dimensional reconstruction, and morphometric analysis, sexual dimorphism was examined with regard to a nine feature masculine trait score that included perineal appendage length (prepuce), anogenital distance, and presence/absence of bone. The presence/absence of ovotestes was discordant in all four mole species for sex differentiation features. For many sex differentiation features, discordance with ovotestes was observed in at least one mole species. The degree of concordance with ovotestes was highest for hairy-tailed moles and lowest for broad-footed moles. In relationship to phylogenetic clade, sex differentiation features also did not correlate with the similarity/divergence of the features and presence/absence of ovotestes. Hairy-tailed and Japanese shrew moles reside in separated clades, but they exhibit a high degree of congruence. Broad-footed and hairy-tailed moles reside within the same clade but had one of the lowest correlations in features and presence/absence of ovotestes. Thus, phylogenetic affinity and the presence/absence of ovotestes are poor predictors for most sex differentiation features within mole external genitalia.

Evolution of Oligo-Miocene talpids (Mammalia, Talpidae) in Europe: focus on the genera Myxomygale and Percymygale n. gen.

New material recovered in the Oligocene locality St-Martin-de-Castillon (Vaucluse, France; MP24) provides a better knowledge of the characteristics of the species vauclusensis in its type-locality, hitherto assigned to the genus Myxomygale (Talpinae, tribe Urotrichini). In Europe, the species assigned to Myxomygale range from Late Eocene/Early Oligocene to the end of the Middle Miocene (MN 7/8). However noticeable differences can be observed in mandibles of these taxa, sometimes even coexisting in the same localities. We propose for the plesiomorphic branch (including M. vauclusensis and M. minor) a new genus, Percymygale, closely related to Myxomygale. Percymygale is consequently also assigned to the tribe Urotrichini. Today, the tribe Urotrichini (American and Japanese shrew-moles) is composed of terrestrial, semi-fossorial species, not well adapted to digging but able to climb small bushes, and foraging in grasslands, forests and covered landscapes. As a result, their limbs protrude laterally from the body (unlike in moles) and their humeri are usually longer with very limited adaptations to digging. Humeri are poorly known for Myxomygale and only fragmentary humeri are known for Percymygale n. gen. making comparisons difficult. However the muzzle development in Percymygale and Myxomygale suggests that Myxomygale was perhaps a better burrower than Percymygale.http://www.zoobank.org/urn:lsid:zoobank.org:pub:E0BDC0FC-ABA2-4A84-AE76-06B3433B432Ehttp://www.zoobank.org/urn:lsid:zoobank.org:act:17E4DD37-24A4-4C7A-A7FEB421CF90F89C

Partial albinism in the Japanese shrew mole, Urotrichus talpoides, from Aichi, Japan

We describe partial albinism (a white-belted coloration) in the Japanese shrew mole (Urotrichus talpoides) from Aichi Prefecture, Japan. This shrew-mole did not present symptoms of generalized types of vitiligo vulgaris. The white-belted coloration may have occurred because of a lack of melanocyte formation due to a deficit of or to abnormalities in neural crest cells during ontogeny.

Food Habits of the Ural Owl (Strix uralensis) During the Breeding Season in Central Japan

Abstract We studied the diet of Ural Owls (Strix uralensis) living in the forests of Mt. Yatsugatake, central Japan, in the context of historic logging activities that have greatly extended the amount of open pasture and consequently modified small mammal availability in the region. We used owl pellets from artificial nest boxes to quantitatively analyze diet composition during the breeding season. We identified 1026 small mammals from 17 owl nests. Mandibles were identified and categorized as wood mice (Apodemus spp.), voles (Microtus sp.), and shrew-moles (Urotrichus talpoides). The small-mammal component of the diet was dominated by wood mice (71%), followed by voles (24%) and shrew-moles (5%). This contrasts sharply with the vole-dominated diets associated with most European Ural Owl populations. We also detected significantly fewer voles among mammalian remains for nests at greater distances from open-pasture habitat. We confirmed previous results from studies of Ural Owls in Japan that suggest elast...

Humerus development in moles (Talpidae, Mammalia)

AbstractThe humerus of fossorial moles has a highly derived anatomy, reflecting the ecological specialization of these animals for digging. It is short and broad, with enlarged muscle attachment sites and pronounced articulations compared to non‐fossorial sister taxa and other mammals. Both condyles are rotated in opposite directions, resulting in a torsion which is unique among eutherian mammals. The development of this exceptional bone was studied in embryonic stages of the fossorial Iberian mole (Talpa occidentalis) from mesenchymal condensation to incipient ossification based on histological serial sections using 3D reconstruction methods. For comparison, embryonic stages of the semi‐fossorial Japanese shrew mole (Urotrichus talpoides) as well as a sister taxon of moles, the terrestrial North American least shrew (Cryptotis parva), were studied. Results show that the humerus of Talpa already shows its derived anatomy with broadened muscle attachment sites and distinct articulations at early cartilaginous stages, when ossification has just started in the mid‐diaphyseal region. The torsion takes place simultaneously with the medial rotation of the forelimbs. The supracondylar foramen is closed in all studied Talpa embryos, but patent in Cryptotis and Urotrichus. This is an example of developmental penetrance, suggesting that variation of adult elements can be found at early stages as well.

Geographic variation in the greater Japanese shrew-mole, Urotrichus talpoides: Combining morphological and chromosomal patterns

Although much information on the species dynamics of small mammals may be gleaned from the integration of morphological and molecular data sets, the two are not routinely combined when species boundaries and definitions are investigated. The greater Japanese shrew-mole (Urotrichus talpoides) presents a rare example of intraspecific and geographical euchromatic chromosomal variation. In this study a combination of 2D landmark-based and outline-based geometric morphometric methods were used to provide the first quantitative examination of variation in skull morphology occurring between populations of U. talpoides. Geographic variation was found to be most conspicuous in ventral and dorsal cranial morphology, and less evident for outline-based analyses of the dentary, thereby indicating differing magnitudes of skeletal plasticity associated with geographic variation in each system. Both ventral and dorsal cranial morphology differed significantly between shrew-moles from western and eastern Honshu, in agreement with previously identified chromosomal variation boundaries. Inclusion of other island populations revealed shape differences between shrew-moles in Kyushu, Tsushima and North Honshu. These results lend general support for the unification of morphological and chromosomal data when assessing species boundaries.

Comparative Morphology of the Papillae Linguales and their Connective Tissue Cores in the Tongue of the Greater Japanese Shrew‐mole, Urotrichus talpoides

The external morphology of the papillae linguales (papillae filiformes, papillae fungiformes and papillae vallatae) and their connective tissue cores (CTCs) of the greater Japanese shrew-mole (Urotrichus talpoides) were analysed by optical and scanning electron microscopy. Papillae filiformes were distributed over the dorsal surface of the apex linguae, and on the rostral and caudal regions of the corpus linguae but were less numerous in the mid-region. They were absent from the radix linguae. A pair of oval papillae vallatae was situated at the border between the corpus linguae and the radix linguae. Papillae foliatae were absent. The epithelial surface of each papilla filiformis consisted of a circular concavity, a ring-like wall and either a single thumb-like process or 2–3 slender pointed processes, depending on their location. The morphology of the CTCs of the papillae filiformes also varied regionally. The papillae linguales of the Japanese shrew-mole were morphologically similar to those of other Talpidae and Soricidae, including the common shrew, particularly with respect to the papillae filiformes in the mid- and caudal regions of the corpus linguae.

A Record of the Lesser Japanese Shrew-Mole Dymecodon pilirostris True, 1886 Captured in Western Part of Tanzawa Mountains for the First Time in Nearly 40 Years.

A Record of the Lesser Japanese Shrew-Mole <i>Dymecodon pilirostris</i> True, 1886 Captured in Western Part of Tanzawa Mountains for the First Time in Nearly 40 Years.

Studies of the Shrew Mole ( Urotrichus talpoides ) I. Age determination, population structure and behavior

Studies of the Shrew Mole ( Urotrichus talpoides ) I. Age determination, population structure and behavior

Evolutionary insights from a genetically divergent hantavirus harbored by the European common mole (Talpa europaea).

BackgroundThe discovery of genetically distinct hantaviruses in shrews (Order Soricomorpha, Family Soricidae) from widely separated geographic regions challenges the hypothesis that rodents (Order Rodentia, Family Muridae and Cricetidae) are the primordial reservoir hosts of hantaviruses and also predicts that other soricomorphs harbor hantaviruses. Recently, novel hantavirus genomes have been detected in moles of the Family Talpidae, including the Japanese shrew mole (Urotrichus talpoides) and American shrew mole (Neurotrichus gibbsii). We present new insights into the evolutionary history of hantaviruses gained from a highly divergent hantavirus, designated Nova virus (NVAV), identified in the European common mole (Talpa europaea) captured in Hungary.Methodology/Principal FindingsPair-wise alignment and comparison of the full-length S- and L-genomic segments indicated moderately low sequence similarity of 54–65% and 46–63% at the nucleotide and amino acid levels, respectively, between NVAV and representative rodent- and soricid-borne hantaviruses. Despite the high degree of sequence divergence, the predicted secondary structure of the NVAV nucleocapsid protein exhibited the characteristic coiled-coil domains at the amino-terminal end, and the L-segment motifs, typically found in hantaviruses, were well conserved. Phylogenetic analyses, using maximum-likelihood and Bayesian methods, showed that NVAV formed a distinct clade that was evolutionarily distant from all other hantaviruses.ConclusionsNewly identified hantaviruses harbored by shrews and moles support long-standing virus-host relationships and suggest that ancestral soricomorphs, rather than rodents, may have been the early or original mammalian hosts.

Host switch during evolution of a genetically distinct hantavirus in the American shrew mole ( Neurotrichus gibbsii)

A genetically distinct hantavirus, designated Oxbow virus (OXBV), was detected in tissues of an American shrew mole ( Neurotrichus gibbsii), captured in Gresham, Oregon, in September 2003. Pairwise analysis of full-length S- and M- and partial L-segment nucleotide and amino acid sequences of OXBV indicated low sequence similarity with rodent-borne hantaviruses. Phylogenetic analyses using maximum-likelihood and Bayesian methods, and host–parasite evolutionary comparisons, showed that OXBV and Asama virus, a hantavirus recently identified from the Japanese shrew mole ( Urotrichus talpoides), were related to soricine shrew-borne hantaviruses from North America and Eurasia, respectively, suggesting parallel evolution associated with cross-species transmission.