Little is known about the communication of Chilean shrew opossums or how they perceive their environment. They likely have poor eyesight due to nocturnal activity and small eyes. Vibrissae are used to sense insects and objects in the environment. Examination of their brains shows large olfactory bulbs, indicating an acute sense of smell (Patterson and Gallardo, 1987).
Communication Channels: tactile ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Chilean shrew opossums were listed in 1994 by the IUCN (International Union for Conservation of Nature and Natural Resources) as vulnerable due to habitat loss and degradation.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: near threatened
Due to few studies, economic importance of Chilean shrew opossums is not known.
Due to few studies, economic importance of Chilean shrew opossums is not known.
Other than their consumption of insects, earthworms and plant material and fungi, little is known about the ecosystem roles of R. raphanurus.
Chilean shrew opossums are semi-fossorial, foraging in the litter layer for soil invertebrates (54% of diet) and earthworms (7%). Another principle component of their diet is plant material and fungi (39%), and they are commonly baited into traps with rolled oats (Meserve et al, 1988).
Animal Foods: insects; terrestrial non-insect arthropods; mollusks; terrestrial worms
Plant Foods: seeds, grains, and nuts
Other Foods: fungus
Primary Diet: carnivore (Insectivore ); mycophage
Chilean shrew opossums have only been found in a small geographic range that covers southern Chile, Chiloe Island, and a small part of southern Argentina (approximately 40 degrees south latitude and 70 degrees west longitude). Captures of Rhyncholestes raphanurus occurred at elevations from sea level to 1135 m (Patterson and Gallardo, 1987). Only two specimens have been captured in Argentina. Once thought to be rare, it is possible that they are abundant in limited habitat types (Meserve et al, 1982).
Biogeographic Regions: neotropical (Native )
Chilean shrew opossums reside in temperate forest habitat. Favorable microclimates include wet areas of southern beech (Nothofagus species) forest with plenty of coarse woody debris and thick understory shrub cover. These marsupials are more frequently caught at elevations lower than 600 meters (Kelt and Martinez, 1989).
Range elevation: 0 to 1135 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest ; rainforest
No data has been gathered on the life span of Chilean shrew opossums. Few trapped individuals have been recaptured, making it difficult to judge life span (Meserve et al, 1982). Because of their small body size, it is likely that they do not live more than a few years.
Chilean shrew opossums are small mammals. Their body size can range from 10 to 13 cm. Their ventral and dorsal portions are dark brown or gray. The tail is solid in color, with short, sparse hairs, and shorter than the head and body.Their shape is shrew-like and the ears are small and rounded (Redford et al, 1992). Determination of gender is through dental formula- males have a conical, single rooted upper canine and females have a double-rooted canine resembling a premolar (Patterson and Gallardo, 1987).
Range length: 10 to 13 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
Little data has been gathered on predation on Chilean shrew opossums. Like most small mammals, they are likely a food base for nocturnal carnivores. Possible vertebrate predators include Buteo polyosoma, Elanus leucurus, Falco sparverius, Geranoaetus melanoleucus, Parabuteo unicinctus; Athene cunicularia, Bubo virginianus, Tyto alba, Dusicyon culpaeus (Lycalopex culpaeus), Philodryas chamissonis, and Tachymenis peruviana (Jaksie et al, 1980).
Chilean shrew opossums are small, cryptic, nocturnal animals and likely avoid most predation by being difficult to find.
Anti-predator Adaptations: cryptic
Little is known about caenolestid mating systems. The seemingly solitary behavior of Chilean shrew opossums (Kelt and Martinez, 1989), as well as random distribution of resources in their environment, suggests a polygynandrous (promiscuous) mating system. Other hypotheses include that they live in family groups which would suggest monogamous mating systems. Neither hypotheses have been tested.
Few studies have been done on the reproductive cycle of Chilean shrew opossums. Females do not have a pouch and possess five to seven teats. Patterns of teat development suggest litters of 5 to 7 or greater (Patterson and Gallardo, 1987). There is evidence that females are capable of reproducing any time of the year, as lactating females have been captured in February, March, May, October, November and December (Nowak, 1999). Males are thought to be reproductively active all year. They possess a cleft penis and paired sperm (Patterson and Gallardo, 1987).
Breeding interval: Breeding intervals are unknown in Chilean shrew opossums.
Breeding season: Chilean shrew opossums may breed throughout the year.
Range number of offspring: 5 to 7.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Little is known about parental care in R. raphanurus. A mother with young has never been captured, suggesting they may use a nest to raise young. The trapping of an adult male, adult female and two juveniles in one trap in a short time period led to the hypothesis that R. raphanurus live in family groups, indicating that both male and female participate in care of young. This hypothesis has not yet been tested (Patterson and Gallardo, 1987).
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
The long-nosed caenolestid (Rhyncholestes raphanurus), also known as the Chilean shrew opossum or long-nosed shrew opossum, is a shrew opossum that occurs in temperate forests of Argentina and southern Chile. It was first described by American zoologist Wilfred Hudson Osgood in 1924. The long-nosed caenolestid resembles Caenolestes species in morphology. It is characterized by a long, pointed snout, small eyes and ears, and one claw on a digit of each of the thin limbs. Little is known of its behavior; it appears to be terrestrial (lives on land), nocturnal (active mainly at night) and omnivorous. It prefers cool, moist areas, and has a small distribution. It is classified as near threatened by the IUCN.
The long-nosed caenolestid is the sole member of its genus, and is classified in the family Caenolestidae. It was first described by American zoologist Wilfred Hudson Osgood in 1924. Two subspecies are recognised:[2][3]
A 2013 morphological and mitochondrial DNA-based phylogenetic study showed that the Incan caenolestid (Lestoros inca) and the long-nosed caenolestid form a clade sister to Caenolestes. The cladogram below is based on this study.[4]
Gray short-tailed opossum (Monodelphis domestica)
Brown four-eyed opossum (Metachirus nudicaudatus)
Incan caenolestid (Lestoros inca)
Long-nosed caenolestid (Rhyncholestes raphanurus)
CaenolestesNorthern caenolestid (C. convelatus)
Dusky caenolestid (C. fuliginosus)
Andean caenolestid (C. condorensis)
Gray-bellied caenolestid (C. caniventer)
Eastern caenolestid (C. sangay)
Caenolestid fossils date to as early as the early Eocene (nearly 55 mya). The generic name derives from the Greek words rhynchos ("snout") and lestes ("robber", "pirate"). The specific name comes from the Greek raphanos ("cabbage"), referring to the thick tail of this caenolestid. The Spanish name for this caenolestid, comadrejita trompuda, is the combination of comadreja ("weasel") and trompa ("snout").[5] Other names for this shrew opossum are Chilean shrew opossum or Chilean caenolestid.[1]
The long-nosed caenolestid resembles Caenolestes species in morphology. In his 1924 account, Osgood recorded external measurements of three specimens. The head-and-body length ranged from 17.5 to 21.5 centimetres (6.9 to 8.5 in), skull length was between 3 and 3.5 centimetres (1.2 and 1.4 in) and hind feet measured 19.5 to 23.5 centimetres (7.7 to 9.3 in). The smooth coat is dark greyish brown, without countershading (greater pigmentation on the upper side).[5] It is characterized by a long, pointed snout, small eyes and ears, and one claw on a digit of each of the thin limbs.[6] This shrew opossum lacks a marsupium[7] (young are attached to the nipples) and has seven nipples, unlike the four typical of other caenolestids.[3] The tail helps in balancing the body during locomotion; the relatively shorter tail could imply lesser agility in the long-nosed caenolestid in comparison to other caenolestids. Moreover, the tail can be used to store fat,[5] and is reportedly thickest during early winter.[3]
A 2007 study recorded dental anomalies such as missing teeth and supernumerary teeth.[8] The rodent-like incisors help in killing vertebrate prey and searching for insects in crevices.[5] The pattern of tooth eruption appears to be largely consistent in all caenolestids – the eruption of procumbent (trailing along the surface without spreading out roots) incisors, followed by the development of closely spaced incisors that distance from one another as the mandible grows, and then the eruption of molars and premolars.[9]
Little is known of the behavior of the long-nosed caenolestid. It appears to be terrestrial (lives on land) and nocturnal (active mainly at night). An omnivore, it feeds on insects and small invertebrates as well as plant material such as fungi. The caenolestid appears to live in burrows and fallen logs;[5] nests may be used temporarily. Lactating females have been reported in May as well as from October to March.[3]
The long-nosed caenolestid occurs in temperate forests of Argentina and southern Chile, and up to altitudes of 1,135 metres (3,724 ft) above the sea level (in Osorno Province, Chile). It prefers cool, moist areas.[3] Known from less than 25 locations, it has a very small distribution.[10] This shrew opossum also marks the southern limit of the distribution of caenolestids.[11] Though locally abundant, the survival of the caenolestid is threatened by deforestation. Its population has declined by nearly 20% since the 1990s due to deforestation and human settlement. The IUCN classifies the long-nosed caenolestid as near threatened.[1]
The long-nosed caenolestid (Rhyncholestes raphanurus), also known as the Chilean shrew opossum or long-nosed shrew opossum, is a shrew opossum that occurs in temperate forests of Argentina and southern Chile. It was first described by American zoologist Wilfred Hudson Osgood in 1924. The long-nosed caenolestid resembles Caenolestes species in morphology. It is characterized by a long, pointed snout, small eyes and ears, and one claw on a digit of each of the thin limbs. Little is known of its behavior; it appears to be terrestrial (lives on land), nocturnal (active mainly at night) and omnivorous. It prefers cool, moist areas, and has a small distribution. It is classified as near threatened by the IUCN.
