Graphiurus ocularis (Smith, 1829)
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https://doi.org/ 10.5281/zenodo.6604339 |
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https://doi.org/10.5281/zenodo.6604266 |
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persistent identifier |
https://treatment.plazi.org/id/9B215C43-FFCD-DD09-C9BD-F3B6FB19F7C6 |
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Carolina |
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Graphiurus ocularis |
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12. View On
Spectacled African Dormouse
Graphiurus ocularis View in CoL
French: Loir du Cap / German: Brillenbilch / Spanish: Liron de anteojos
Other common names: Gemsbokmuis, Namtap, Spectacled Dormouse
Taxonomy. Sciurus ocularis A. Smith, 1829 ,
near Plettenberg Bay, western Cape Province, South Africa.
Placed in the subgenus Graphiurus . Originally described in the genus Sciurus due to their general resemblance to tree squirrels. J. Smuts in 1832 proposed Graphiurus as the oldest valid genus name for African dormice for the form capensis, a synonym of the type species of the genus, G. ocularis . O. Thomas and M. A. C. Hinton in 1925 argued that differences between G. ocularis , two species of rock-dwelling African dormice ( G. platyops and G. rupicola ), and all other “ordinary” arboreal dormice were such that the three groups of African dormice should be recognized as separate genera. Because G. ocularis is the type species for the genus, they retained this species as the sole member of the genus Graphiurus , distinguished by its “minute” premolar and simple occlusal surface. Some authors such as G. M. Allen in 1939 and A. Roberts in 1951 followed Thomas and Hinton’s recommendations to recognize separate genera of African dormice. Others, such as J. R. Ellerman in 1940, voiced skepticism. Ellerman initially retained the three groups as subgenera, but in 1953, Ellerman and colleagues only recognized two subgenera, Graphiurus , containing G. ocularis , and Claviglis, containing all other African dormice; X. Misonne in 1974, H. Genest-Villard in 1978, and M. E. Holden in 1993 followed this arrangement. E. G. Potapova in 2001 and I. Y. Pavlinov and Potapova in 2003 placed all species of African dormice except G. nagiglasii and G. crassicaudatus in subgenus Graphiurus , an arrangement followed by Holden in 2005. Monotypic.
Distribution. Endemic to South Africa (Eastern Cape, Northern Cape, and Western Cape Provinces). View Figure
Descriptive notes. Head-body 117-145 mm, tail 103-150 mm, ear 15-25 mm, hindfoot 20-26 mm; weight 72-85 g. No sexual dimorphism reported. The Spectacled African Dormouse is the second largest species within the genus. Striking black, white, and gray color pattern on head and shoulders allows easy identification; facial pattern vaguely resembles that of a Gemsbok (Oryx gazella), hence the common name variation of “Gemsbokmuis.” Dorsal pelage is medium silver-gray to silver-charcoalgray; texture is woolly and thick, and fur is moderately long (rump hairs 11-12 mm, guard hairs up to 16 mm). Ventral pelage is dark gray washed with white. Chin and chest of some individuals are dark chestnut; some researchers have suggested that color is a result ofstaining offur by certain ingested food items such as earwigs, but reddish color may be inherent because it appears on young Spectacled African Dormice prior to weaning. Head is silver gray, paler gray to white on top ofsnout. Cheeks are white and form part of white sharply demarcated lateral stripe that extends from cheeks to shoulders; dorsal and ventral pelage colors are clearly delineated. Eyes are large. Eye mask is conspicuous and broad, formed by wide black stripe extending from base ofear to muzzle underneath vibrissae. Fars are brown, moderately large, and rounded. Conspicuous white supra-auricular patches and post-auricular patches are present. Hindfeet are white or white with dark metatarsal streak, somewhat wide and short, ¢.18% of head-body length. Tail is moderately long, c.85%of head-body length; tail hairs are shorter at base, 10-15 mm, and longer at tip, up to 35 mm. Tail hairs are slate gray at base and white for most oftheir distal length so that tail appears frosted. Ventral tail surface is darker and is solid brownish black medially, fringed with white laterally; tail tip is white. Skull is long, moderately flattened, and broad. Greatest length ofskull is 34-2-37-5 mm, zygomatic breadth is 18:3-20-9 mm, and upper tooth row length is 3-3-5 mm. External and cranial measurements listed are based on specimens from Northern Cape and Western Cape Provinces. Chromosome number is 2n = 46. Females have four pairs of nipples (1 pectoral + 1 abdominal + 2 inguinal = 8).
Habitat. South-West Arid (Karoo) and South-West Cape Biotic Zones from sea level to elevations of 1585 m. Spectacled African Dormice have been captured in rock piles, stone kraals, and rocky outcrops formed predominantly by sandstones and they are most commonly found in outcrops more than 3 m high that offer elevated horizontal and vertical crevices for nesting and shelter. Namaqua Micaelamys ( Micaelamys namaguensis) and Cape Elephant Shrews (Elephantulus edwardii) have been observed to inhabit the same rocky outcrops as Spectacled African Dormice and used lower, less steep rock surfaces and horizontal fissures closer to the ground, whereas Spectacled African Dormice scaled vertical or near-vertical rock faces to use fissures higher up on outcrops. The type specimen was “found in a hollow tree;” no other specimens have been observed or captured in trees.
Food and Feeding. The Spectacled African Dormouse is insectivorous and carnivorous. Diets primarily consist of arthropods, vertebrates, eggs, and honey. Insects consumed include grasshoppers, ants, beetles, and bees. They prey on vertebrates, including birds that roost in rock crevices such the Cape bunting (Emberiza capensis) and lizards such as the southern rock agama (Agama atra) and red-sided skinks (Trachylepis homalocephala). Fecal analyses reveal no seasonal variation in diet, no differences in diet between juveniles and adults, or between males and females. Captive Spectacled African Dormice are said to consume unnatural foods such as crackers, fruit, meat, honey, dog food, and rat pellets. Climbers and other visitors to the Cederberg Mountains huts report that Spectacled African Dormice devour any food items left unprotected and rummage in open backpacks in search of food. Nesting habits of captive individuals suggest that they carry food items to feeding areas in their nests before consuming them.
Breeding. Litter sizes of Spectacled African Dormice are 4-6 young; two litters may be produced each season, with a litter interval of 6-8 weeks. Young are born in spring and summer (August-mid-February), remain with the mother or breeding pair for 5-6 weeks, and then seek out their own territory, usually in less favorable habitat due to occupation ofhigher quality habitat by adults. Developing young are able to emit aggression calls by ¢.2 weeks old.
Activity patterns. The Spectacled African Dormouse is nocturnal. During warm seasons, they have been observed foraging within 30 minutes after sunset and until shortly before sunrise. Spectacled African Dormice remain active throughout the year, but they enter facultative daily torpor or multiday torpor bouts, or hibernate for up to one month, in response to lower ambient temperatures or scarcity of food. In captivity, they seem to be unable to tolerate ambient temperatures greater than 35°C.
Movements, Home range and Social organization. Spectacled African Dormice are predominantly rupicolous. Flattened cranium and well-developed foot pads allow them to scale vertical rock faces and move through narrow rock crevices. They prefer to travel along rocks aboveground, even if taking a ground-level path would considerably shorten the distance; fluorescent powder tracking suggests that individuals lay scent trails and that males and females follow common routes. Home range sizes were 1-1-2-3 ha for adult females and 2-1-3-8 ha for adult males in a 7-5ha study site. Densities, inclusive of all age groups, are reported to be 1-8-3-1 ind/ha; densities of adult population were 0-9-1-3 ind/ha in 7-8ha during a four-year study; mean population size during breeding season was calculated to be seven adults, and male-female ratio was 1:1. Density is in part determined by availability of suitable rocky habitat. There is little information available regarding specific nesting habits because Spectacled African Dormice nests are located deep within rock fissures. Captive individuals carried food to specific areas of their nests and defecated in or near the nest. The social structure of these dormice primarily consists of male-female pairs plus nestlings; pairs occupy the most favorable habitats, and pairs have been documented to persist up to eleven months until one individual disappears or is displaced. Lone individuals, including young dispersing from parental nests, travel farther and nest in less favorable habitats. It is not known whether males or females primarily maintain territories, but males appear to be forced to move more often due to displacement. Spectacled African Dormice behave aggressively toward conspecifics. At first, they vocalize softly by making a “woomph woomph” noise and then produce a “spit-urr” call with increasing volume and frequency that builds up to a sudden harsh cry to intimidate an intruder; they also fluff up and raise their tail, showing the black ventral surface, and open their mouths. It has been hypothesized that aggressive displays and vocalizations are important in maintaining control of territories. Average life span of the Spectacled African Dormouse is thought to be c.4 years in the wild; one captive individual lived six years.
Status and Conservation. Classified as Least Concern on The IUCN Red List. The Spectacled African Dormouse is relatively widespread, and although not common,it is wellknown, well-studied, and well-represented in protected areas. There are no obvious major threats and no reason to infer a decline, but continued population monitoring is necessary. A more appropriate classification might be Data Deficient, which would better reflect lack of information regarding population demographics across its discontinuous distribution and fewer than 50 museum specimens.
Bibliography. Allen, G.M. (1939), Avery & Avery (2011), Channing (1984, 1987 1997), Coetzee et al. (2008b), De Graaff & Rautenbach (1983), Ellerman (1940), Ellerman et al. (1953), Genest-Villard (1978), Happold & Lock (2013), Holden (1993, 2005, 2013), Misonne (1974), Pavlinov & Potapova (2003), Perrin & Ridgard (1999), Potapova (2001), Rautenbach (1982), Roberts (1951), Skinner & Smithers (1990), Smith (1829), Smithers (1986), Smuts (1832), Taylor et al. (1994), Thomas & Hinton (1925), Van Hensbergen & Channing (1989).
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