Chaetocauda sichuanensis Wang Youzhi 1985
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Gliridae
Chaetocauda
Chaetocauda sichuanensis

description: 23.
Sichuan Dormouse
Chaetocauda sichuanensis
French: Lérotin du Sichuan / German: Sichuan-Bilch / Spanish: Liron de Sichuan
Other common names: Chinese Dormouse
Taxonomy. Chaetocauda sichuanensis Wang Youzhi, 1985,
Wang-lang Nature Reserve, [2480 m,] Pingwu county, northern Sichuan Province, China.
Most authors agree with placement of C. sichuanensis in the subfamily Leithiinae, including Wang Youzhi in 1985, M. E. Holden in 1993, R. Daams and H. de Bruijn in 1994, O. LL. Rossolimo and colleagues in 2001, and Holden in 2005. Its position within the subfamily is uncertain and is regularly debated. Few researchers have had access to specimens, and thus hypotheses regarding evolutionary relationships and taxonomy have been based solely on photographs and illustrations in the original description. In 1993, Holden included this species in the genus Dryomys because in certain respects it resembled specimens of forest dormice from Balochistan, Pakistan, that Holden later described in 1996 as a new species, Dryomys niethammeni. C. sichuanensis and D. niethammer: have inflated bullae, long incisive foramina, and certain features of the baculum in common. Holden in 2005 later recognized Chaetocauda at the generic level and stated reevaluation of cranial and dental traits suggested a close relationship with Mouse-tailed Dormice as Wang Youzhy first hypothesized in 1985, a position first substantiated by G. Storch in 1994 based on a suite of cranial and dental characters, and later amplified by Rossolimo and colleagues in 2001. Recently, A. T. Smith in 2008 and 2013 provided the first illustration of C. sichuanensis pelage, and depicted the tail as being thinly haired, similar to that of Myomimus, except for the prominent tufted tip; this lends further credence to affinity ofthis dormouse with mouse-tailed dormice. Distribution of extant and extinct species of Myomimus as summarized by Daams and de Bruijn in 1994 likewise adds plausibility to the idea that C. sichuanensis may be a relictual descendent population of Myomimus or Myomimuslike ancestors, isolated by chance, environmental factors, or vicariance events in the seismically active mountains of northern Sichuan where it occurs. In 1994, Storch also hypothesized that C. sichuanensis and Selevinia betpakdalaensis are each others’ closest relatives, based upon the shared characteristics of grooved incisors, reduced complexity of occlusal surface of cheekteeth, and greatly inflated auditory bullae, but based on studies of middle ear morphology, E. G. Potapova hypothesized in 2001 that S. betpakdalaensis and mouse-tailed dormice are sister taxa. Due to inaccessibility of specimens, molecular phylogenetic analyses of Gliridae were not able to include Chaetocauda to aid in clarifying its taxonomic position.
Distribution. SC China, known only from the type locality in Wanglang Nature Reserve, Pingwu County, N Sichuan Province. Distributional limits are not known.
Descriptive notes. Head-body 90-91 mm, tail 92-102 mm, ear 17-18-5 mm, hindfoot 18-5-19 mm; weight 24-5-36 g. No sexual dimorphism reported. The Sichuan Dormouse is readily distinguishable by its tufted tail and combination of grooved incisors, wide interorbit, long incisive foramina, and greatly inflated bullae. Dorsal pelage is reddish brown; ventral pelage is white. Dorsal and ventral pelage colors are clearly delineated. Sides of body and cheeks appear paler; head color matches that of dorsal pelage. Eyes are large and outlined by dark chestnut eye-rings; inconspicuous chestnut eye mask extends from eyes to muzzle. Ears are brown, large, and rounded. Cheeks are white, forming part of pale lateral stripe that extends from cheeks to shoulders. Pale gray postauricular patches are present. Hindfeet are white, ¢.20% of head-body length. Tail is long, ¢.110% of head-body length; dorsaltail color is similar to that of dorsal pelage, and ventral surface is paler. Tail tip has conspicuous tuft of dense hairs; hairs on tip of tail are 6-9 mm long. Greatest length of skull is 26-3-27-2 mm, zygomatic breadth is 15-1-15-3 mm, incisive foramina length is 5-5-2 mm, auditory bullae length is 8-:8-8-9 mm, and upper tooth row length is 3-5 mm. External and cranial measurements listed are those of type and paratype specimens collected in Wanglang Nature Reserve, China. Chromosome number is not known. Females have four pairs of nipples (lI pectoral + 1 abdominal + 2 inguinal = 8).
Habitat. Subalpine old growth of mixed broadleaf and conifer forest. Wanglang Nature Reserve is situated in the Min (= Minshan) Mountains at elevations of 2320-4891 m; elevational distribution of the Sichuan Dormouse is not known. In addition to a variety of bamboo (including Fargesia sp. and Bambusa sp.) growing throughout much of the Reserve, predominantly virgin forest is dominated by conifers such as fir (Abies sp.), pine (Pinus sp.), larch (Larix sp.), and spruce (Picea sp.), and trees of the Fagaceae family such as oak (Quercus sp.) and beech (Fagus sp.). Other common tree species include red birch (Betula albosinensis, Betulaceae); deodar cedar (Cedrus deodara) and dragon spruce (Picea asperata), both Pinaceae; gingko (Ginkgo biloba, Ginkgoaceae); dove tree (Davidia involucrata, Cornaceae); katsura (Cercidiphyllum japonicum, Cercidiphyllaceae); and Chinese tulip (Liriodendron chinense, Magnoliaceae).
Food and Feeding. Little is known about the diet and foraging habits of the Sichuan Dormouse, but contents of the type specimens contained mixture of green plant material and starch.
Breeding. Estimated litter size is four young. Pregnant females were captured in May. One adult female was carrying four fetuses, two in each uterine horn, measuring 11 mm in diameter.
Activity patterns. The Sichuan Dormouse is probably predominantly nocturnal, although it has been occasionally observed during the day foraging for leaves and moving about in trees.
Movements, Home range and Social organization. The Sichuan Dormouse is probably solitary. Only five individuals have been captured in the 30 years since it was first described. Sichuan Dormice construct nests 3-3-5 m off the ground on small branches. In 1985, Wang Youzhi described one nest in detail. Outer supporting skeleton of the nest was made of small branches bent to form a frame, and it was attached with moss. Entire nest was ¢.12 cm in diameter, and it was thickest toward the center. Central area was wrapped in layers of red birch bark, and its inner chamber was lined with fine needles. Lined bottom of the nest was c.3 cm in depth. Diameter of circular nest entrance was ¢.3 cm. Sichuan Dormice might also nest in tree cavities.
Status and Conservation. Classified as Data Deficient on The IUCN Red List. There are only five known specimens of the Sichuan Dormouse, and information regarding habitat parameters, population trends, and potential threats is lacking. It was previously listed in 1996 as Endangered. Wanglang Nature Reserve, in which the Sichuan Dormouse occurs, has been protected for more than 50 years and provides critical habitat for the Giant Panda (Ailuropoda melanoleuca) and many other species;it is connected with other suitable Giant Panda habitat by bamboo “corridors,” consisting of planted strips of forest and bamboo that link reserves and pockets of forestUntil more information is available regarding population size, density, and biology,it is difficult to assess the Sichuan Dormouse’s conservation risk and what efforts should be recommended. Deforestation is the most pressing threat; despite status of Wanglang as a nature reserve, logging activities within nature reserves and adjacent areas have been documented. Illegal loggers often clear cut the easier to reach riparian forest, resulting in devastating habitat destruction and landslides. Other threats include expanding human development and construction of roads throughout the bamboo-forest corridor.
Bibliography. Daams & de Bruijn (1994), Holden (1993, 1996a, 2005), Rossolimo et al. (2001), Potapova (2001), Smith (2008a, 2013), Smith & Johnston (2008p), Storch (1994), Wang Youzhi (1985), WWF (2015).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Gliridae, pp. 838-889 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 857-858, DOI: 10.5281/zenodo.6604339