Sylvilagus mansuetus, Nelson, 1907

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Leporidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 107-148 : 115

12.

San Jose Brush Rabbit

Sylvilagus mansuetus

French: Lapin de San José / German: San-José-Strauchkaninchen / Spanish: Conejo de San José

Taxonomy. Sylvilagus mansuetus Nelson, 1907 ,

“San José Island, Gulf of California [Baja California del Sur], Mexico.”

This species is an insular allospecies closely related to S. bachmani on the adjacent peninsula of Baja California. Formerly, S. mansuetus was placed as a subspecies of S. bachmani . Sylvilagus mansuetus and S. bachmani are the only species of Sylvilagus known to have retained the putative ancestral karyotype (2n = 48), shared by all known species of Lepus and Romerolagus . Monotypic.

Distribution. SW San José I, Baja California Sur, Mexico.

Descriptive notes. Head-body 340 mm, tail 44 mm, ear 60 mm, hindfoot 73 mm; weight ¢.800 g (all measurements from a single individual). The San Jose Brush Rabbit is one of the smaller species of Sylvilagus . Dorsal fur and head are pale buffy or yellowish gray. Sides are paler and grayer than back. Ears are gray, and nape is dull and pale ocherous buff. Forelegs are ocherous clay and shade into dingy white forefeet. Posterior surface of hindlegs is browner than back, and top of hindfeet are white. Throat is paler than sides, and ventral fur is white.

Habitat. Desert habitat restricted to the south-western coastal plains of the San José Island. Desert habitat consists of primarily seven plant species: jojoba ( Simmondsia chinensts, Simmondsiaceae ); blue palo verde ( Cercidium peninsulare, Fabaceae ); Maytenus phyllanthoides ( Fabaceae ); Adam’s trees ( Fouquieria diguetii, Fouquieriaceae ); Stenocerus thurbei and S. gummosus (both Cactaceae ); and ashy limberbush ( Jatropha cinerea, Euphorbiaceae ). Five San Jose Brush Rabbits were observed to rest in shade of blue palo verde trees.

Food and Feeding. There is no information available for this species.

Breeding. Two pregnant San Jose Brush Rabbits with two embryos each and two lactating females were recorded in November 2008. Two nests also were found. One nest was in the base of a cardon cactus near a desert thorn ( Lycium sp. , Solanaceae ). Its entrance was 11 cm x 12 cm wide, and den was 15 cm deep, with a total length of 8:5 cm. Nest was lined with fur, dry leaves of blue palo verde, and small branches of desert thorn. Two dead young were found in the nest. The other nest was at the base of a cholla ( Opuntia cholla, Cactaceae ). Entrance was 8-5 x 10-5 cm wide, and den was 12 cm deep. Nest was lined with fur, dry leaves of blue palo verde, small branches of ashy limberbush, and desert thorn. No young were found in the nest.

Activity patterns. San Jose Brush Rabbits are most active between sunset and 02:00 h and from ¢.06:00 h to 10:00 h.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Critically Endangered on The IUCN Red List. Maximum total population of the San Jose Brush Rabbit is estimated at 500-700 individuals, but it might be significantly lower. Informal surveys conducted in 1995 and 1996 were compared with quantitative surveys in 2008, and it was concluded that the population had declined but the magnitude of decline was not quantified. These surveys restricted distribution to the south-western coastal plain at 10 m above sea level, which reduced the extent of occurrence to only 20 km? in a single continuous population. This is the smallest distribution of any lagomorph species. Major conservation threats to the San Jose Brush Rabbit are feral cats and maybe domestic dogs; habitat loss and competition with feral goats; illegal hunting; development of a tourist area including a golf course, private airport, and small marina; and planned reactivation of a salt mine. Management recommendations include enforcement of protected status of the San Jose Brush Rabbit, with goals of stopping hunting and removal of feral cats and goats. All wildlife on San José Island, including the San Jose Brush Rabbit, is protected under Mexican law. Research is needed on its biology, ecology, population status, genetics, and potential for inbreeding depression due to its small population and distribution.

Bibliography. Cervantes, Lorenzo et al. (1996), Chapman & Ceballos (1990), Hall (1981), Hoffmann & Smith (2005), Lorenzo & Alvarez-Castarieda (2011), Lorenzo etal. (2011), Nelson (1907, 1909), Thomas & Best (1994a).

Figures

33. Indian Hare (Lepus nigricollis), 34. Burmese Hare (Lepus peguensis), 36. Scrub Hare (Lepus saxatilis), 37. African Savanna Hare (Lepus victoriae), 38. Yarkand Hare (Lepus yarkandensis), 39. Ethiopian Highland Hare (Lepus starcki), 40. Cape Hare (Lepus capensis), 41. Abyssinian Hare (Lepus habessinicus), 42. Tolai Hare (Lepus tolai), 43. Desert Hare (Lepus tibetanus), 44. Yunnan Hare (Lepus comus), 45. Woolly Hare (Lepus oiostolus), 46. Snowshoe Hare (Lepus americanus), 47. Black-tailed Jackrabbit (Lepus californicus), 48. Black Jackrabbit (Lepus insularis)

Distribution. SW San José I, Baja California Sur, Mexico.