HMW 5 – Species accounts: Gray-bellied Shrew-opossum (Caenolestes caniventer)

Text de família: 

Genus CAENOLESTES

O. Thomas, 1895

 

1. Gray-bellied Shrew-opossum Caenolestes caniventer

French: Cénoleste à ventre gris / German: Graubäuchige Opossummaus / Spanish: Ratón marsupial de vientre gris

Other common names: Gray-bellied Caenolestid, Pale-bellied Shrew-opossum

Taxonomy. Cænolestes caniventer Anthony, 1921, “El Chiral, Western Andes; altitude, 5350 ft.; Prov. Del Oro, Ecuador.”

This species is monotypic.

Distribution. W slope of the Andes in C & S Ecuador and NW Peru (N and S of the Huancabamba Depression), extending onto E slope in NW Peru.

Descriptive notes. Head–body 9·1–12·8 cm, tail 11·8–15 cm, hindfoot 2·4–2·7 cm; weight 29–47 g. The Gray-bellied Shrew-opossum is sexually dimorphic in size, with males generally being larger than females. Northern shrew-opossums (all five species of Caenolestes) include forms with conical, single-rooted canine teeth in both sexes; the last upper incisor mostly fills the space between the third incisor, and the canine, first, and second premolars of comparable size; and they have a forward-facing orientation of the infraorbital foramen (opening below the eye socket). The Gray-bellied Shrew-opossum possesses a conspicuous dark pectoral spot on the grayish ventral pelage that contrasts strongly with dorsal pelage. Antorbital vacuity is open, and post-palatine torus is curved. A species of myobiid mite (Caenolestomyobia faini) was described from the Gray-bellied Shrew-opossum.

Habitat. Primary and secondary subtropical and temperate montane forests, with canopies 15–20 m in height and a thick herbaceous understory of ferns and saplings. Gray-bellied Shrew-opossums also inhabit secondary shrubby forest dominated by Ocotea (Lauraceae), with sparser canopies and ground cover. They occur over an elevational range of 1630–3340 m.

Food and Feeding. Gray-bellied Shrew-opossums are opportunistic feeders, concentrating mostly on invertebrates. Caterpillars, centipedes, arachnids, a variety of other invertebrates, fruits, and occasionally small vertebrates are eaten.

Breeding. In southern Ecuador, pregnancy in Gray-bellied Shrew-opossums occurs in September; the sole gravid female examined contained two embryos, one in each uterine horn.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. The Gray-bellied Shrew-opossum uses trails, tunnels, and cavities under tree roots along streams and on steep mountainous slopes.

Status and Conservation. Classified as Near Threatened on The IUCN Red List. The Gray-bellied Shrew-opossum is probably experiencing population declines inferred from habitat conversion to agriculture and from logging; it is restricted to forest within a relatively narrow elevational band.

Bibliography. Albuja & Patterson (1996), Anthony (1923), Barkley & Whitaker (1984), Barnett (1991), Bochkov & OConnor (2009), Lunde & Pacheco (2003), Ojala-Barbour et al. (2013), Tirira (2007).

 

2. Condor Shrew-opossum Caenolestes condorensis

French: Cénoleste du Condor / German: Anden-Opossummaus / Spanish: Ratón marsupial del Cóndor

Other common names: Andean Caenolestid

Taxonomy. Caenolestes condorensis Albuja & Patterson, 1996, “ Achupallas, … camp on the upper plateau of the Cordillera del Cóndor, in the Provincia de Morona-Santiago, Ecuador, coordinates 3° 27’ 03” S, 78° 29’ 9” W, elevation 2,080 m.”

This species is monotypic.

Distribution. Known only from the Cordillera del Cóndor, E slope of the Andes, on the border of Ecuador and Peru.

Descriptive notes. Head–body 13–14 cm, tail 12·3–13 cm, hindfoot 2·7–3 cm; weight 43–48 g. The Condor Shrew-opossum is sexually dimorphic in size, with males generally being larger than females. It possesses an inconspicuous pectoral spot on the dark grayish ventral pelage, large upper canines (reaching 3·5 mm in length), and a squared post-palatine torus. The Condor Shrew-opossum is the largest known species of shrew-opossum, with a skull length of more than 36 mm.

Habitat. Primarily ecotone between forested slopes with canopies 5–6 m in height and a cold, humid plateau dominated by a bromeliad-filled heath less than 1·5 m tall. The Condor Shrew-opossum occurs at elevations of c.2000 m, and unlike other species of shrew-opossums, it does not seem to be associated with steep montane forests.

Food and Feeding. There is no specific information for this species, but all three reported captures of the Condor Shrew-opossum were made using peanut butter and oatmeal baits in traps placed on the ground.

Breeding. There is no information available for this species.

Activity patterns. There is no information available for this species.

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

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Condor Shrew-opossum is known only from a single location (Achupallas), in a very specific habitat that is restricted to the Cordillera del Cóndor, a mountain range isolated from the main chain in the eastern Andes. There are no currently identified threats to the habitat. Further research is necessary to determine the ecology and complete extent of the distribution of the Condor Shrew-opossum.

Bibliography. Albuja & Patterson (1996), Ojala-Barbour et al. (2013), Tirira (2007, 2011).

 

3. Blackish Shrew-opossum Caenolestes convelatus

French: Cénoleste noirâtre / German: Schwarzbraune Opossummaus / Spanish: Ratón marsupial negruzco

Other common names: Northern Caenolestid, Northern Shrew-opossum

Taxonomy. Caenolestes convelatus Anthony, 1924, “Las Maquinas, Western Andes 7000 feet [2134 m] altitude, on trail from Aloag to Santo Domingo de los Colorados,” Pichincha, Ecuador.

The distributions of the subspecies are not well established. The distribution of Colombian shrew-opossums (this species and C. fuliginosus) is in need of focused sampling and systematic revision. Two subspecies recognized.

Subspecies and Distribution.

C. c. convelatus Anthony, 1924 – W slope of the Andes in N Ecuador at elevations of 1100–2300 m.

C. c. barbarensis Bublitz, 1987 – W range of the Andes in Colombia at elevations of 1800–3800 m.

Descriptive notes. Head–body 12·1–14·6 cm, tail 7·2–14·1 cm, hindfoot 2·5–2·9 cm; weight 40–45 g. The Blackish Shrew-opossum is sexually dimorphic in size, with males generally being larger than females. It is large and blackish brown on dorsum, contrasting with a pale olive-gray venter. Antorbital vacuity in skulls of Blackish Shrew-opossums is narrowed, sometimes becoming altogether roofed by bone.

Habitat. Subtropical and cloud forests, perhaps as high as 4100 m above sea level.

Food and Feeding. Diet of the Blackish Shrew-opossum from the wild has never been reported, but a captive male flourished during five days on a diet of earthworms and pieces of beef.

Breeding. Little is known about the reproductive biology of the Blackish Shrew-opossum, but a male captured in mid-September had enlarged testes (9 × 7 mm).

Activity patterns. There is no information available for this species.

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

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Blackish Shrew-opossum occurs in an area less than 20,000 km2, with severe fragmentation and a continuing decline in habitat because of livestock, agriculture, and road building, especially in its southern distributional segment occupied by the nominate subspecies.

Bibliography. Alberico et al. (2000), Goff & Timm (1985), Ojala-Barbour et al. (2013), Timm & Price (1985), Tirira (2007), Tirira & Burneo (2011).

 

4. Dusky Shrew-opossum Caenolestes fuliginosus

French: Cénoleste gris / German: Ecuador-Opossummaus / Spanish: Ratón marsupial sedoso

Other common names: Common Gray Shrew-opossum, Dusky Caenolestid, Silky Shrew-opossum

Taxonomy. Hyracodon fuliginosus Tomes, 1863, “Ecuador.”

Caenolestes fuliginosus was originally described under the generic name Hyracodon, but that name was already used for an extinct rhinoceros, and thus it was renamed. Limits of distribution for each subspecies in Colombia remain poorly known. Three subspecies recognized.

Subspecies and Distribution.

C. f. fuliginosus Tomes, 1863 – higher forested and páramo elevations of the Andes in N & C Ecuador.

C. f. centralis Bublitz, 1987 – forests and páramos of the W, C & E ranges of the Andes in Colombia and extreme SW Venezuela (Táchira).

C. f. obscurus O. Thomas, 1895 – apparently restricted to the vicinity of Bogotá.

Descriptive notes. Head–body 9·6–13·4 cm, tail 10·3–13·9 cm, hindfoot 2–2·8 cm; weight 25–32 g. The Dusky Shrew-opossum is sexually dimorphic in size, with males generally being larger than females. Of the five species of Caenolestes, the Dusky Shrew-opossum has weakest countershading of dorsal and ventral pelage; its tail is uniform brown. Antorbital vacuity forms a comma-shaped opening, and upper canines rarely exceed 1·9 mm in length. A flea (Cleopsylla monticola), chigger (Crotiscus danae), myobiid mite (Caenolestomyobia lukoschusi), and chewing louse (Cummingsia albujai) are all known from the Dusky Shrew-opossum.

Habitat. From tall wet forests with closed canopies and little undergrowth to densely vegetated scrubland and pastures. The Dusky Shrew-opossum occurs in an elevational range from 2134 m in Boyacá (Colombia) to 4300 m on Pichincha Volcano (Ecuador); it occurs at elevations of 2200–2400 m on the Páramo de Tamá (eastern Colombia and western Venezuela).

Food and Feeding. The Dusky Shrew-opossum is strongly insectivorous, and stomach contents show its use of larval and adult Diptera, Lepidoptera, Coleoptera, Orthoptera, Araeneae, and Scorpiones. It also feeds on earthworms, fruits, and small vertebrates. Offered a variety of baits, the Dusky Shrew-opossum showed a strong preference for “meat” baits (small birds and bacon rind versus rolled oats).

Breeding. Little is known about the reproductive biology of the Dusky Shrew-opossum, but four lactating females were captured in late August in Cauca Department, Colombia; none were carrying young.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. Dusky Shrew-opossums appear restless, constantly moving through leaf litter and ground cover in search of food. They appear to use small trails in moss and forest litter.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Dusky Shrew-opossum has a broad geographical and habitat distribution and thus, presumably, a large global population. No major threats occur with its distribution, but on the eastern periphery of its distribution, it was listed as vulnerable on the Venezuelan Red List in August 2013.

Bibliography. Albuja & Patterson (1996), Bochkov & O’Connor (2009), Bochkov et al. (2013), Herrick (1921), Linares (1998), O’Connell (2006), Ojala-Barbour et al. (2013), Osgood (1921), Timm & Patterson (2008), Timm & Price (1985), Tirira (2007).

 

5. Sangay Shrew-opossum Caenolestes sangay

French: Cénoleste du Sangay / German: Sangay-Opossummaus / Spanish: Ratón marsupial de Sangay

Taxonomy. Caenolestes sangay Ojala-Barbour et al., 2013, “2,795 m on the eastern slopes of the Andes at Tinguichaca (2° 13’ 48·72” S, 78° 26’ 42·14” W) in Sangay National Park, Morona Santiago, Ecuador, along the Macas–Riobamba highway.”

This species is monotypic.

Distribution. Known only from the E slope of the Andes in S Ecuador, along the Macas–Riobamba highway, at elevations of 2050–2962 m.

Descriptive notes. Head–body 9·9–13·7 cm, tail 9·5–13 cm, hindfoot 2·2–2·8 cm; weight 30–53 g. The Sangay Shrew-opossum is sexually dimorphic in size, with males generally being larger than females. It is medium-sized and has grizzled brownish-gray dorsum and distinctly contrasting cream to pale-gray venter without pectoral spot. Tail is noticeably bicolored, with a very dark dorsum and warmer, drab-brown venter. Major palatine foramen of the Sangay Shrew-opossum is especially long and broad, and posterior margin of the post-palatine torus is curved and delicate.

Habitat. Primary and secondary upper montane cloud forest, with abundant ferns, mosses, bromeliads, and orchids. The Sangay Shrew-opossum lives on steep slopes and in riparian forests.

Food and Feeding. The Sangay Shrew-opossum appears to share insectivorous habits of other species of shrew-opossums. Stomach contents of three individuals contained a variety of insect and plant remains, including a click-beetle larva (Elateridae), an arachnid (Lycosidae), a dipteran, a wasp (Pteromalidae), an unidentified larva, bryophytes, rhizomes, an unidentified fruit, small dark hairs, and an intact, unidentified flatworm that may have been an endoparasite.

Breeding. There is no information available for this species.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no specific information available for this species, but five individuals marked and released at the site of capture were not recaptured in four subsequent trapping periods. Like other shrew-opossums, Sangay Shrew-opossums may become trap-shy.

Status and Conservation. As a newly described species, the conservation status of the Sangay Shrew-opossum has not been assessed on The IUCN Red List. Nevertheless, despite its use of primary and secondary forests, it may qualify as Vulnerable because of its restricted geographical distribution (many co-occurring species are endemic to this section of the Andes) and declining population inferred from progressive deforestation.

Bibliography. Ojala-Barbour et al. (2013).

 

Genus LESTOROS

Oehser, 1934

 

 

6. Incan Shrew-opossum Lestoros inca

French: Cénoleste du Pérou / German: Peruanische Opossummaus / Spanish: Ratón marsupial andino

Other common names: Incan Caenolestid, Peruvian Shrew-opossum

Taxonomy. Orolestes inca O. Thomas, 1917, “Torontoy, 14,000 feet” Cuzco, Peru.

Lestoros inca was originally described under the generic name Orolestes, which was already used for a dragonfly; G. H. H. Tate in 1934 proposed Cryptolestes, which was also preoccupied by a beetle. P. H. Oehser in 1934 proposed the valid name Lestoros. The specific epithet gracilis was proposed for shrew-opossums from various localities to the south and east of the type locality, but recent analyses indicate there is little appreciable clinal or intraspecific variation. As a result, gracilis is regarded as a synonym of inca. Monotypic.

Distribution. Over headwaters of four drainage systems along the E slope of the Andes from Ocobamba, Cusco Region (SE Peru) to Llamachaqui, La Paz Department (W Bolivia).

Descriptive notes. Head–body 9–12 cm, tail 10·5–13·5 cm, hindfoot 2·2–2·4 cm; weight 20–35 g. Male Incan Shrew-opossums are slightly larger than females. The Incan Shrew-opossum differs from other genera of shrew-opossums in having an inflated nasofrontal region, a thickened anterior root to the zygomata, a diastema between upper incisors and canine, a minute or missing first premolar, a large lower third incisor, and double-rooted canines in both sexes. It is gentle in the hand. It is host to a number of ectoparasitic mites, at least one chewing louse (Cummingsia maculata), and a roundworm (Pterygodermatites hymanae). Its parasitic associations are especially interesting: six of the 29 species of the mite genus Prolistrophorus are associated with the Incan Shrew-opossum, while the other 23 species parasitize various Neotropical rodents.

Habitat. Upper cloud forest and wet elfin forest to highly disturbed Baccharis (Asteraceae) scrub. Incan Shrew-opossums are abundant at the ecotone of elfin forest and “pajonal,” a grassy and shrubby formation present at tree line in the central Andes. In Manu National Park and Biosphere Reserve, they occur at elevations of 2190–3350 m; nearby (26 km by road north-west of Ollantaytambo and in Cuzco), they occur at elevations up to 3700 m.

Food and Feeding. Incan Shrew-opossums eat insects and other small invertebrates.

Breeding. Female Incan Shrew-opossums in Manu were lactating in November and March. Females typically have four inguinal mammae, but they sometimes possess a median fifth on the abdomen.

Activity patterns. Incan Shrew-opossums are active, both in the wet season and dry season.

Movements, Home range and Social organization. Incan Shrew-opossums are readily captured in traps set among tree roots or in runways and baited with peanut butter and oatmeal, sardines, or meat.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Incan Shrew-opossum has a relatively large distribution; it occurs in a variety of habitats, river drainages, and protected areas, and it is presumed to have a large total population. It is unlikely to be declining in numbers.

Bibliography. Bochkov (2011), Bublitz (1987), Fain & Lukoschus (1977), Goff (1982, 1987), Jiménez & Patterson (2012), Kirsch & Waller (1979), Martin (2013), Myers & Patton (2008), Oehser (1934), Solari et al. (2006), Tate (1934), Thomas (1917).

 

Genus RHYNCHOLESTES

Osgood, 1924

 

 

7. Long-nosed Shrew-opossum Rhyncholestes raphanurus

Other common names: Chilean Shrew-opossum

French: Cénoleste du Chili / German: Langnasen-Opossummaus / Spanish: Ratón marsupial trompudo

Other common names: Chilean Caenolestid, Chilean Shrew-opossum, Fat-tailed Caenolestid, Long-nosed Caenolestid

Taxonomy. Rhyncholestes raphanurus Osgood, 1924, “mouth of Rio Inio, south end of Chiloé Island,” Biobio, Chile.

The subspecies continentalis was originally described as a distinct species on the basis of height of the secondary cusp on canine teeth of females. Two subspecies recognized.

Subspecies and Distribution.

R. r. raphanurus Osgood, 1924 – Chiloé I, S Chile.

R. r. continentalis Bublitz, 1987 – SC Chile (Los Lagos Region) and adjacent Argentina (Nahuel Huapi National Park).

Descriptive notes. Head–body 9·7–12·8 cm, tail 6·5–8·8 cm, hindfoot 1·9–2·4 cm; weight 23–30 g, but up to 36–40 g. Male Long-nosed Shrew-opossums tend to be somewhat larger than females. Long-nosed Shrew-opossums are characterized by having a very long rostrum, open palate, double infraorbital foramen, subequally bifid lateral upper incisors, and sexually dimorphic upper canines, which are single rooted and caniniform in males and double-rooted and premolariform in females. Unlike other shrew-opossums, but like some other marsupials living in highly seasonal environments such as the fat-tailed mouse opossums (Thylamys spp.), the Patagonian Opossum (Lestodelphys halli), and the Monito del Monte (Dromiciops gliroides), tail of the Long-nosed Shrew-opossum swells seasonally with fat stores, from 4–5 mm in proximal diameter during summer to 9–11 mm in early winter. The specific epithet raphanurus (“radish tail”) refers to this seasonal accumulation of fat in the tail. Females were thought to have four inguinal and one abdominal mammae, but three abdominal mammae are present in some, the odd one invariably on ventral midline. Long-nosed Shrew-opossums are host to a large commensal rove beetle, Chilamblyopinus piceus, and the fleas Barreropsylla excelsa, Cleopsylla vidua, Plocopsylla athena, and Plocopsylla diana.

Habitat. Appears restricted to temperate rainforest habitats, with Nothofagus (Nothofagaceae) as the overstory dominant and a dense understory of Chusquea (Poaceae), Podocarpus and Saxegothaea (both Podocarpaceae). Predictive models of the distribution of the Long-nosed Shrew-opossum have strong contributions from precipitation and precipitation-related variables. It is captured mainly on moist ground, at the bases of trees, alongside moss-covered logs, and in dense cover. It has also been recorded in or near disturbed areas and has been captured in isolated forest remnants in regions dominated by agriculture and grazing. The Long-nosed Shrew-opossum occurs from sea level on Chiloé Island to an elevation of 1135 m along the slopes of Osorno Volcano (La Picada, Los Lagos Region, Chile).

Food and Feeding. At La Picada, the diet of the Long-nosed Shrew-opossum consisted of invertebrates (55%) and vegetation and fungi (40%); annelid worms accounted for 8% of all food ingested. One individual caged with a newly captured Abrothrix sp. (a mouse also native to Valdivian forests) made no attempt to prey on it, as would species of Caenolestes in similar circumstances.

Breeding. Female Long-nosed Shrew-opossums are reproductively active during austral summer; lactating or pregnant females have been recorded in December–March and in May, October, and November. No young have ever been found attached to nipples of lactating females, raising the prospect that they use a nest to rear offspring. Male Long-nosed Shrew-opossums appear to be sexually active throughout the year and have been noted with well-developed testes in February, March, and May.

Activity patterns. At La Picada, all but one capture of Long-nosed Shrew-opossums took place at night, suggesting that they are strongly nocturnal. Caudal fat storage has been associated with seasonal activity patterns and extended torpor in other marsupials, but Long-nosed Shrew-opossums have been captured during winter on snowpack. Year-round activity and an evident inability to arouse from hypothermia suggest that they do not rely on hibernation or torpor to any great extent. Long-nosed Shrew-opossums do not thrive in captivity and attempts to maintain them in cages on varied diets have failed after only a day or two.

Movements, Home range and Social organization. In four years of live trapping at La Picada, only two of 36 released Long-nosed Shrew-opossums were recaptured. Successive captures of adults and juveniles in the same trap did suggest that they might live in family groups. Casual observations of newly captured individuals suggest the Long-nosed Shrew-opossum may be slower, less agile, and more strictly terrestrial than other shrew-opossums.

Status and Conservation. Classified as Near Threatened on The IUCN Red List. The Long-nosed Shrew-opossum has a localized geographical distribution and is strongly association with intact Nothofagus forests, a habitat type that is being heavily exploited. Although the Long-nosed Shrew-opossum has been recorded from remnant forests in agricultural landscapes, it does not inhabit naturally disturbed areas (e.g. bamboo-choked landslides), even those alongside primary forests where it is relative abundant. An ongoing population decline is inferred from habitat loss due to logging activities and the paucity of new occurrence records (the last new distribution record, from 1997, was a shrew-opossum taken by a raptor). The Long-nosed Shrew-opossum can be considered a diagnostic element of the Valdivian biogeographic province. Like the cricetid rodents Pearson’s Long-clawed Akodont (Pearsonomys annectens) and Sanborn’s Akodont (Abrothrix sanborni), it is found only in the center of the larger Valdivian ecoregion. Further information is needed on distribution, area of occupancy, and effects of threats on populations of the Long-nosed Shrew-opossum, because it may be more threatened than currently suspected. The Long-nosed Shrew-opossum approaches classification for Threatened status under IUCN’s population decline criteria (criterion A).

Bibliography. Ashe & Timm (1988), Beaucournu & Gallardo (1991), Beaucournu & Kelt (1990), Birney et al. (1996), Bublitz (1987), Flores et al. (2007), Gallardo & Patterson (1987), Iriarte (2008), Kelt (2000), Kelt & Martínez (1989), Mann (1978), Martin (2007, 2011), Meserve, Kelt & Martínez (1991), Meserve, Lang & Patterson (1988), Meserve, Murúa et al. (1982), Monjeau, Bonino & Saba (1994), Monjeau, Sikes et al. (1997), Osgood (1924), Patterson (2008b), Patterson & Gallardo (1987), Patterson et al. (1989, 1990), Pine et al. (1979), Tamayo et al. (1987).