537.

Darwin’s Hocicudo

Oxymycterus nasutus

French: Hocicudo a nez long / German: Darwin-Grabmaus / Spanish: Ratén hocicudo de Darwin

Other common names: Long-nosed Hocicudo

Taxonomy. Mus nasutus Waterhouse, 1837, Maldonado, Maldonado, Uruguay.

Oxymycterus nasutus is the type species of the genus. Monotypic.

Distribution. S Brazil (Parana, Santa Catarina, and Rio Grande do Sul states) and Uruguay.

Descriptive notes. Head-body 123-131 mm, tail 87-97 mm, ear 17-18 mm, hindfoot 27-28 mm; weight 50-90 g. See general characters of the genus under the Anazonian Hocicudo ( O. amazonicus) account. Darwin’s Hocicudo is a small species of Oxymycterus . Dorsum can be vivid dark orange, with head and mid-dorsum lined with black, or much darker and duller, without black lining, or intermediate between two chromatic extremes. Sides and venter are paler in both extremes. Forefeet and hindfeet are well-haired, light to more strongly brown above. Tailis slightly bicolored to unicolored.

Habitat. Wet grasslands and steppes, coastal sandbanks, pasture lands, and edges of streams.

Food and Feeding. Darwin's Hocicudo mainly eats insects. Frequencies of occurrence in contents of twelve stomachs were: Coleoptera ( Tenebrionidae, Scarabaeidae, Lampyridae, Chrysomelidae, Carabidae, Pselaphidae, Dytiscidae) 100%; Hymenoptera (Formicidae) 83-3%; Diptera ( Sciaridae, Bibionidae, Chironomidae, Tipalidae) 83-3%; Hemiptera (Timgidae, Pentatomidae) 41-6%; Oligochaeta (earthworms) 33-3%; Lepidoptera ( Noctuidae, unidentified families) 25-5%; Orthoptera ( Gryllidae, Acrididae, Gryllacrididae) 25%; Chilopoda (centipedes) 25%; Homoptera ( Cicadellidae, Fulgoridae) 16-6%; Gastropoda (slugs) 16-6%; Aranea 16-6%; and plants (unidentified fragments) 16-6%.

Breeding. Reproduction of Darwin’s Hocicudo occurs year-round, mostly in September—April. Pregnant females had 1-4 embryos, usually two.

Activity patterns. Darwin’s Hocicudo is diurnal and crepuscular, varying according to photoperiod and temperature.

Movements, Home range and Social organization. Darwin’s Hocicudo commonly use trails of species of Cavia (guinea pigs) and Hydrochoerus (capybaras) as pathways through tall grass.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Barlow (1969), D'Elia & Teta (2016), Goncalves & Oliveira (2004), Gonzalez (2001), Gonzalez & Martinez (2010), Hershkovitz (1994), Hoffmann et al. (2002), Massoia & Fornes (1969), Oliveira (1998), Oliveira & Goncalves (2015), Paise & Vieira (2006), Pecanha (2015).