Clyomys laticeps
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
Echimyidae
Clyomys
Clyomys laticeps

description: 12.
Broad-headed Spiny-rat
Clyomys laticeps
French: Rat-épineux a téte large / German: Breitkopf-Stachelratte / Spanish: Rata espinosa de cabeza ancha
Taxonomy. Echimys laticeps Thomas, 1909,
“Lagoa Santa, on the Rio Sao Francisco, Minas Gerais,” Brazil.
Clyomys laticeps was placed originally in Echimys, but O. Thomas in 1916 designated laticeps as the type species of the new genus Clyomys. In the most recent review in 2015, A. M. R. Bezerra and C. R. Bonvicino regarded whartoni (named by J. Moojen in 1952 as a subspecies of laticeps) and bishopt (named by F. D. de Avila-Pires and M. R. C. Wutke in 1981 as a full species), as synonyms of Thomas's laticeps. Monotypic.
Distribution. C Brazilian states of Bahia, Distrito Federal, Goias, and Minas Gerais, extending S into Sao Paulo State and W to Mato Grosso and Mato Grosso do Sul states, and into E Paraguay.
Descriptive notes. Head-body 150-295 mm, tail 48-89 mm; weight 100-350 g. The Broad-headed Spiny-rat is medium-sized and semi-fossorial, with short ears, short limbs, long and powerful fore claws, short tail (¢.33% of head-body length) sparsely covered with hair only partially covering underlying scales, and coarse and spinose fur. General color varies from grizzled rufous and black to grizzled yellow and black dorsally, and whitish to buffy ventrally, with or without grayish or pale rufous patches in gular region. Skull of the Broad-headed Spiny-rat is broad, and rostrum is short and wide. Anterior projection of premaxillary bone and inferior projection of premaxillary are short, and well-developed canal for nerve passage is present on floor of infraorbital foramen. Auditory bullae are hypertrophied, extending posteriorly beyond paraoccipital processes when viewed from behind. Incisive foramina are narrow and elongate, and mesopterygoid fossa extends to middle of M* Sphenopalatine foramen and sphenopalatine vacuities are well developed. Incisors are robust, upper cheekteeth have three roots and three transverse lophs, and mandibular teeth also have three lophs. Male phallus is subcylindrical, elongated, and straight, with longitudinal grooves on sides, small spines covering epidermis and extending into the intromittent (external) sac, and lappet extending only slight beyond the crater. Baculum is simple, long, narrow, and slightly concave at proximal end. Karyotype is variable: specimens from Sao Paulo State are 2n = 34 and FN = 58 or 60; those from Distrito Federal are 2n = 34 and FN = 62; those from Mato Grosso do Sul State are 2n = 34 and FN = 58; and those from Goias State are 2n = 32 and FN = 54.
Habitat. Savanna with considerable structural complexity including unflooded grassland and shrubby vegetation with ground cover of grasses and areas of the Paraguayan Chaco, a drier western extension of the cerrado. In the dry season, Broad-headed Spiny-rats occupy areas with partially continuous canopy of 2-3 m tall, with discontinuous herbaceous cover; in the wet season, they occur in areas with partially continuous herbaceous cover, 0-2-1 m tall, but with 10-30% arboreal cover. Density may be positively influenced by abundance of understory palms.
Food and Feeding. Broad-headed Spiny-rats are herbivorous, consuming mostly monocots, and they store plant parts in burrow systems. They can be important consumers and dispersers of palm seeds, particularly those of Attalea geraensis, A. phalerata, and Syagrus petraea (all Arecaceae). In one comparative study, the Broad-headed Spiny-rat had the most specialized diet and microhabitat requirements of the assemblage of coexisting rodent species.
Breeding. Pregnant Broad-headed Spiny-rats have been captured, with single embryos, in June-December, primarily during the dry season but extending into the wet season. Juveniles have been recorded in the wet season (December—April).
Activity patterns. The Broad-headed Spiny-rat is stated by some to be diurnal, but nocturnal foraging excursions on the ground have been documented. Like many fossorial-to-subterranean species, activity pattern is likely to be without an explicit diel pattern. The Broad-headed Spiny-rat exhibits a low resting O, metabolism and tolerance to hypoxia, both characteristics of other fossorial mammals.
Movements, Home range and Social organization. The Broad-headed Spiny-rat is semi-fossorial and colonial, digging complex burrow systems to maximum depths of 1-5 m and with lateral extensions up to 37 m. There is a strong relationship between presence of Clyomys and burrows of armadillos (Cingulata) in some parts of its distribution.
Status and Conservation. Classified as Least Concern on The IUCN Red List. “Bishop’s Fossorial Spiny-rat” (C. bishopi) is treated here as a synonym of the Broadheaded Spiny-rat but is classified as Data Deficient on The IUCN Red List because of the absence of recent information, with the caution that its taxonomic status needed clarification. The Broad-headed Spiny-rat is patchily distributed but locally abundant. There are no documented conservation threats, but habitat conversion to agriculture, especially in the southern part of its distribution, may be detrimental.
Bibliography. de Almeida & Galetti (2007), de Avila-Pires & Wutke (1981), Barros et al. (2004), Bezerra & Bonvicino (2015b), Bezerra & de Oliveira (2010), Bueno et al. (2004), Camilo-Alves & Mourao (2010), de Carvalho & Bueno (1975), Lacher & Alho (1989), Moojen (1952b), Thomas (1909a, 1916b), Vieira (1997 2003).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Echimyidae, pp. 552-604 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 560, DOI: 10.5281/zenodo.6623649