| Durrell's vontsira | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Eupleridae |
| Genus: | Salanoia |
| Species: | S. durrelli |
| Binomial name | |
| Salanoia durrelli Durbinet al., 2010 | |
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| Distribution ofSalanoia durrelli[2] | |
Durrell's vontsira (Salanoia durrelli)[3] is a small, reddish-brown, fox-likemammal native to the island ofMadagascar. Discovered in 2004, it lives only in the biodiverse wetlands ofLake Alaotra. Durrell's vontsira belongs to the familyEupleridae, a group of meat-eating, cat- or fox-like mammals (of the orderCarnivora) found only on Madagascar. The species is closely related to thebrown-tailed mongoose (Salanoia concolor), with which it forms the genusSalanoia. The two are genetically similar, butmorphologically distinct, andS. durrelli wasdescribed as a new species in 2010.
A small, reddish-brown carnivore,Salanoia durrelli is characterized by broad feet with prominentpads, reddish-buff underparts, and broad, robust teeth, among other differences from the brown-tailed mongoose. In the only two weighed specimens, body mass was 600 and 675 g (21.2 and 23.8 oz). It is a marsh-dwelling animal that may feed oncrustaceans andmollusks. The Lake Alaotra area is a threatened ecosystem, andS. durrelli may also be endangered by competition withintroduced species.
An individualSalanoia durrelli was observed swimming in 2004 by theDurrell Wildlife Conservation Trust (DWCT) during a survey ofbamboo lemurs (Hapalemur) in theLac Alaotra area, the largestwetlands of Madagascar. The animal was captured, photographed, and then released, but examination of the photograph showed that it could not be identified with any known species of Malagasy carnivoran (familyEupleridae). Therefore, two specimens were caught in 2005 by the DWCT. One was killed to facilitate additional morphological comparisons.[4] In 2010, it was formally described asSalanoia durrelli in a paper by conservationist Joanna Durbin and a team of scientists from theClimate, Community & Biodiversity Alliance,Nature Heritage, theNatural History Museum,Conservation International, and the DWCT.[5] Thespecific name,durrelli, honorsGerald Durrell, a noted conservationist and the founder of the DWCT.[6] Thecommon namevontsira is aMalagasy name for various species withinGalidiinae.[7]
Previously, local villagers had already reported the presence of a small carnivoran at Alaotra, and it was speculated that the animal was the closely relatedbrown-tailed mongoose (Salanoia concolor) of eastern Madagascar.[8]Salanoia durrelli was placed in the genusSalanoia, which previously included only the brown-tailed mongoose.S. durrelli shows substantialmorphological differences from the brown-tailed mongoose, but themitochondrial DNA of the two species is very similar.[9] The discoverers chose to recognize the Lac Alaotra population as a separate species in view of its significant morphological differentiation. The observed morphological distinctiveness might be the result ofadaptations to life in the Alaotra wetlands, similar to the Alaotra bamboo lemur species,Hapalemur alaotrensis, which is also recognized as a distinct species despite being genetically close to the more widespreadHapalemur griseus.[10]
Salanoia durrelli most closely resembles the brown-tailed mongoose,[4] which is a small,gracilemongoose-like carnivoran.[12] It is reddish-brown overall, paler than the brown-tailed mongoose.[13] The head andnape are speckled.[6] The underparts are reddish-buff, not brownish as in the brown-tailed mongoose.[13] Most of the tail is similar in color to the body, but the tip is yellowish-brown. The inner side of the well-furred external ear (pinna) is reddish-buff. The broad feet are naked below, with the naked skin buff on the forefeet and dark brown on the hindfeet, and show prominentpads. Each of the five digits on the fore- and hindfeet bears a long, dark brown claw. There are rows of stiff hairs along the outer margins of the feet.[6] In contrast, the brown-tailed mongoose has narrower feet with more poorly developed pads.[13] InS. durrelli, the fur is long and soft.[6]
In theholotype specimen, a female, the head and body length was 310 mm (12 in), the tail length was 210 mm (8.3 in), the hindfoot length was 66.8 mm (2.63 in), the ear length was 17.5 mm (0.69 in), and the body mass was 675 g (23.8 oz). In another specimen, a male which was captured and released, the head and body length was about 330 mm (13 in), the tail length was about 175 mm (6.9 in), and the body mass was 600 g (21 oz).[6] Based on these limited data,S. durrelli may be slightly smaller than the brown-tailed mongoose.[13]
The skull generally resembles that of the brown-tailed mongoose, but the rostrum (front part) is broad and deep, thenasal bones are broad and short, and the region of thepalate is broad. Themandible (lower jaw) is robust and shows a high, steeply risingcoronoid process (a projection at the back of the bone).[13] Statistical analysis of measurements of the skulls and teeth strongly separatesS. durrelli from specimens of the brown-tailed mongoose.[14]
Salanoia durrelli has a more robustdentition than the brown-tailed mongoose; the teeth have larger surface areas.[13] The first and second upperincisors are smaller than the third, which is separated by a pronounceddiastema (gap) from thecanine tooth.[15] The canine is more robust than in the brown-tailed mongoose. The first upperpremolar is small, but the second and third are larger; these two teeth are shorter and broader than in the brown-tailed mongoose.[16] The fourth premolar is large, as is the first molar.[15] The second upper molar is less than one-third the size of the first, and is more highly reduced than that of the brown-tailed mongoose, which is about two-thirds the size of the first molar.[16] The first lower incisor is smaller than the other two. The lower canine, premolars, and first molar are well-developed. The second molar is broad,[15] but smaller than in the brown-tailed mongoose.[16]
Salanoia durrelli has been recorded atAndreba, a marshy area at 750 m (2,460 ft) above sea level on the eastern coast ofLac Alaotra.[6] The nearest occurrence of the brown-tailed mongoose is about 55 km (34 mi) from Alaotra. The first observed specimen was swimming; it may have fled from human activity on the shore. The two others were caught on mats of floating vegetation. Thus,S. durrelli occurs in a marsh habitat—quite different from the forest-dwelling brown-tailed mongoose.S. durrelli may use its robust dentition to feed on prey with hard parts, such ascrustaceans andmolluscs, in addition to smallvertebrates, rather than insects, which the more gracile-toothed brown-tailed mongoose eats. Indeed, the two specimens ofS. durrelli were captured using traps baited with fish and meat.S. durrelli is similar in many respects to the larger mainland Africanmarsh mongoose (Atilax paludinosa), a carnivorous wetland-dweller that also uses mats of vegetation to eat and sleep on.[17]
The unique habitat of Lac Alaotra is threatened by pollution, destruction of marshes for the construction ofrice fields, overfishing, andintroduced species such as exotic fish, plants, theblack rat (Rattus rattus), and thesmall Indian civet (Viverricula indica), another small carnivoran.[18] A bird restricted to the area, theAlaotra grebe (Tachybaptus rufolavatus), was declared extinct in 2010[19] and the population of the bamboo lemur fell by about 30% from 1994 to 1999.[20] As a narrowly distributed species with a small population,S. durrelli is likely to be threatened by degradation of its habitat and perhaps competition with the small Indian civet and the black rat, but itsconservation status has not yet been formally assessed. The DWCT is working to conserve the Lac Alaotra area and the region has been designated as aprotected area.[18]
Media related toSalanoia durrelli at Wikimedia Commons