Galidictis grandidieri, Wozencraft, 1986

Don E. Wilson & Russell A. Mittermeier, 2009, Eupleridae, Handbook of the Mammals of the World – Volume 1 Carnivores, Barcelona: Lynx Edicions, pp. 330-351 : 349

6.

Grandidier’s Vontsira

Galidictis grandidieri

French: Galidie de Grandidier / German: Grof 3er Breitstreifenmungo / Spanish: Galidia de Wozencraft

Other common names: Grandidier's Mongoose, Votsotsoke

Taxonomy. Galidictis grandidiensis Wozencraft, 1986 ,

Madagascar.

Galidictis grandidiensis was subsequently emended to G. grandidieri . After the recent description of this species based on two modern specimens, one of which had precise collection information, subfossil remains were identified from a cave about 50 km south ofthis site. If the subfossil remains had been studied before the recent description of this taxon, it would have been named as an extinct taxon. Monotypic.

Distribution. Extreme SW Madagascar.

Descriptive notes. Head-body 45-48 cm, tail 30-32. 6 cm, ear 9.9-5 cm, hindfoot 3.9-4. 5 cm; weight 1.1-5 kg. Recent fieldwork of|. Jeglinski and colleagues has provided additional body mass data: one adult male weighed 1723 g and four adult females had a mean weight of 1494 g. Other than body mass, there is no evidence of sexual dimorphism in this species. The body is typically mongoose-like, with a relatively long pointed snout. The bushy tail lacks rings and is a little less than one-half of the head and body length. The dorsal and ventral pelage is dark grayish-beige, the tail white, and the rostrum and feet grizzled reddish-brown. The distal portions of the ears are covered with a fine layer of short fur. Eight dark brown longitudinal stripes on the dorsum, all roughly parallel and about 5-7 mm wide, run from behind the ears and converge at the base of the tail. The 8-12 mm spaces between thestripes are white and slightly wider than the stripes but with considerable variation between individuals. The feet are notably elongated and there is webbing between the toes. The hindfeet are longer than the forefeet. The claws are long and non-retractable.

Habitat. This species occurs in the rugged limestone zone to the south of the Onilahy River known as the Mahafaly Plateau, which is aligned along a north-south axis. It is known from an elevational range of 35 to 145 m. This portion ofthe island receives on average less than 400 m of rainfall per year and daily temperatures can exceed 40°C. Soon after its original description in 1986, Grandidier’s Vontsira was “rediscovered” in the portion of the Mahafaly Plateau just to the east of the coastal plain comprising the large alkaline Lac Tsimanampetsotsa; one of the type specimens was collected at this site. Grandidier’s Vontsira can be found in two distinct local xerophytic vegetational communities: at the base of the plateau, which is dominated by Didierea madagascariensis ( Didiereaceae ) and a variety of Euphorbiaceae and Burseraceae ; and in the spiny bush formation on the exposed limestone escarpment on the western portion of the Mahafaly Plateau. At numerous sites on the lower western side of the plateau, there is the resurgence of an underground aquifer along a north-south geological fault. Considerable portions of the upland and eastern portions of the plateau are without water sources for tens of kilometers. Most of the recent sightings ofthis species are at sites along this fault line, where there are natural water sources. While it is unknown if Galidictis is obliged to drink water on a regular basis, the prey base near these water sourcesis higher in density and diversity than surrounding areas without water.

Food and Feeding. Little is known about the food habits of this Vontsira. During an ornithological expedition to Lac Tsimanampetsotsa in 1929, this carnivore was found soon after dark digging up the carcasses of skinned birds. On the basis of some unpublished scat analyses of material collected at Lac Tsimanampetsotsa, it feeds predominantly on invertebrates. By far the most common was hissing cockroaches ( Gromphadorhina ). Other prey types include locusts, scorpions, and rarely, vertebrates. There is some evidence that it might feed on radiated tortoise (Geochelone radiata) and perhaps carrion.

Activity patterns. Grandidier’s Vontsira is strictly nocturnal, becoming active shortly after sunset and returning to its den well before dawn. It was thought to be exclusively terrestrial, but recent observations ofJ. Jeglinski indicate that it climbs in trees.

Movements, Home range and Social organization. Few details are currently available, but an ongoing radio-tracking study by researchers from the University of Hamburg should fill in numerous details. Preliminary results, based on a trapping study, indicate that minimum densities are about five animals per km®. Current data indicate that the home range of malesis relatively large and probably overlapping between individuals, resulting in lower density than the females. In one case, an animal moved during a single night 1-5 km direct-line distance. Solitary individuals and groups of two are frequently observed. More rarely, groups of up to five are seen. Observations of single animals are most likely predominantly of males; pairs are generally of females with their offspring; and sightings of three or more animals are disproportionately of males. In male groups, aggressive interactions can be observed and the females generally initiate these encounters towards the males. Easily visible at night, the white tail probably has an important signaling function. This species places its dens in the labyrinth of holes and caves in the karstic limestone making up the Mahafaly Plateau. These are generally located in areas of exposed rock without vegetation and generally associated with nearby latrine sites. In a few known cases, the crevices reach depths of several meters, where these animals can escape the intense day heat. One den was found in a hollow tree about 3 m off the ground. On the basis of a radiotracking study, during a period of 16 consecutive days, a female with juvenile utilized seven different dens aligned along the limestone cliff across a maximum distance of 1 km. Current evidence seems to indicate that the same burrow is not necessarily used on consecutive days. There is no evidence that this species excavates burrows, but given the rocky substrate it lives on, this is not unexpected. Latrine sites are notably conspicuous and found near prominent features of the landscape (e.g., hill crests, prominent rocks, and outcrops).

Breeding. Few details available. It has been proposed that there is not a fixed reproductive season in this species, and they breed throughout the year. During a rapid survey at Lac Tsimanampetsotsa in November 1989, a number of captured females were in different stages of reproduction, including lactating, pregnant, and in estrus; sub-adults of different ages were also trapped. Thus,it was concluded that this species breeds throughout the year. However, given the high degree of seasonality of meteorological patterns, particularly rainfall, it is assumed that the prey base of Grandidier’s Vontsira would show notable fluctuations. These patterns might be partially offset in places by the permanent water sources along the fault line. Recent data document some seasonality in the testicle volume of adult males, which suggests some seasonality in reproduction. However, females were observed during the same period with offspring of notably different sizes, which supports the hypothesis that reproductive activity is not seasonal. A specimen collected in March had two placental scars, which would indicate a litter size of up to two. Females have one pair of inguinal mammae.

Status and Conservation. Listed in The IUCN Red List as Endangered. However, the result of a Conservation Breeding Specialist Group workshop sponsored by the [UCN/ SSC held in 2001 and attended by specialists working on Madagascar Carnivores gave the status of this species as Threatened. The calculated surface area of the narrow band of habitat where Grandidier’s Vontsira has been observed is 442 km?, of which 118 km? falls within the Parc National de Tsimanampetsotsa. On the basis of preliminary trapping data from different areas along the Mahafaly Plateau, a rough estimate of 6-8 individuals per km* has been advanced. This translates to a population within its known distribution of approximately 2650-3540 animals. Recently, based on more extensive trapping data, an estimate of five individuals per km* has been suggested, which provides an estimate of about 2200. A significant portion ofits range is in a zone of relatively undisturbed spiny bush habitat at the western edge of the Mahafaly Plateau and in a region that has been proposed for an extension of the Parc National de Tsimanampetsotsa. This zone is relatively free of heavy anthropogenic pressure, other than browsing by cattle, which occurs mostly at the foot of the plateau, and some exploitation of forest resources for local utilization (construction wood and medicinal plants).

Bibliography. Conservation Breeding Specialist Group (SSC/IUCN) (2002), Goodman (1996b), Goodman, Ganzhorn & Rakotondravony (2003), Goodman, Raherilalao et al. (2002), IUCN (2007), Mahazotahy et al. (2006), Rand (1935), Wozencraft (1986, 1987, 1990).

Figures

On following pages: 2. Falanouc (Eupleres goudotii); 3. Spotted Fanaloka (Fossa fossana); 4. Ring-tailed Vontsira (Galidia elegans); 5. Broad-striped Vontsira (Galidictis fasciata); 6. Grandidier's Vontsira (Galidictis grandidier:; 7. Narrow-striped Boky (Mungotictis decemlineata); 8. Brown-tailed Vontsira (Salanoia concolor.

Distribution. Extreme SW Madagascar .