Mountain Kleintenrek
| Mountain Kleintenrek | ||||||||||||
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| Scientific name | ||||||||||||
| Microgale monticola | ||||||||||||
| Goodman & Jenkins , 1998 |
The mountain-Kleintenrek ( Microgale monticola ), even mountain-Kleintanrek is a mammalian species of the genus microgale within the family of tenrecs . It lives in the heights of two mountain ranges in the northeast of the island of Madagascar , where it occurs in a total of four locations. The animals represent medium-sized representatives of the Kleintenreks. Like other Kleintenreks, it is characterized by a strong, spindle-shaped body and an elongated head with a narrow snout. They have a relatively long swan that is longer than the rest of the body. Moist mountain forests in valleys and on slopes serve as habitat. The way of life of the mountain small tenrec has hardly been researched. The species was first described in 1998, its population is threatened.
features
Habitus
The Gebirgs-Kleintenrek is a medium-sized representative of the Kleintenreks. Its head-torso length is 7.2 to 9.2 cm, its tail length 9.8 to 11.7 cm. The tail becomes a little longer than the rest of the body. The weight varies from 12 to 17.5 g. In terms of physique, the mountain Kleintenrek is similar to other members of the genus. It is moderately robust, the body has a spindle shape, the limbs are short and strong, the head is long and pointed at the front, the ears reach lengths of 12 to 16 mm. The fur on the back appears dark gray to slightly gray. The individual hairs have silver-gray bases and initially banded with dark brown, then red-brown shafts, while the tips are again tinted with dark brown. Guide hairs are characterized by gray-brown bases, the shaft is dark brown throughout. Dark brown tones also dominate on the belly, the individual hairs as well as the guide hairs here are similar to those on the back, but their shafts and tips are more yellow-brown, with the individual hairs sometimes brown tones also appear. The tail is dark brown on top, slightly lighter on the underside and is covered by a thin coat of short hair, so that the tail scales remain clearly visible. The front and rear feet each have five rays with slightly elongated fingers and toes. They become moderately long, the forefoot is a little wider. The rear foot measures between 19 and 21 mm in length. The front and rear feet are similar in structure. The rays II to IV are the longest, the first (inner) ray only extends to the base of the second ray, the fifth to the beginning of the last limb of the fourth ray. The upper sides of the feet are covered with dark brown fur, the soles are bare, but there is thin hair on the sides at the edges. Females have three pairs of mammary glands , two in the groin area and one variable in the chest or stomach area.
Skull and dentition features
The skull is average in length, its greatest length is 24.5 to 25.8 mm, its greatest width measured at the cranium 10.1 to 11.1 mm. The rostrum is slightly elongated, the nasal bone extends back to the cheekbone . The rear section of the skull is rounded and high, the frontal bone widens significantly here. The constriction behind the eyes narrows the skull only slightly. The lower jaw has a slightly robust construction, the horizontal body runs slightly sinusoidally in the longitudinal axis . Overall, the lower jaw becomes 17.3 to 17.5 mm long and the crown process 5.3 to 5.6 mm high.
The dentition consists of 40 teeth with the following dental formula together: . The front teeth up to the first or second premolar (P2 or P3) are not closed, but are separated from each other by short diastemas . The two inner incisors in both the upper and lower jaw are comparatively large, while the outer one is rather small. Just like the canine, they have additional cusps on the tooth crowns. The molars are characterized by a zalambdodontic occlusal surface pattern with three distinctly pronounced cusps. The anterior premolar (P2) is relatively large, in the lower jaw it is almost as large as the following premolar (P3). The molars show hardly any differences to those of the other generic representatives. The last upper molar, in particular, is greatly reduced in size. The length of the upper row of teeth varies from 12.1 to 12.8 mm.
distribution
The mountain Kleintenrek is endemic in northern Madagascar . Its occurrence is currently limited to four locations in two mountain ranges in the Antsiranana province . The two mountains, the Marojejy massif in the northeast and the Anjanaharibe massif in the southwest, both rise to heights of over 2000 m. They are separated from the Andapa Basin, which is used intensively for agriculture , and are only 40 km away from each other. The species lives there in a relatively narrow strip of elevation that extends from 1550 to 1950 m above sea level. The landscape is determined by misty mountain forests and plant communities consisting of hard- leaved plants . The animals prefer moist valley floors, slopes made of bamboo and rock ridges. They share their habitat with several other small tenreks. so the Cowan-Kleintenrek ( Microgale cowani ), the little long-tailed Kleintenrek ( Microgale longicaudata ) and the Zwergkleintenrek ( Microgale parvula ), as a single type but of the mountain-Kleintenrek limited to the height range. So far, around two dozen individuals are known, around a quarter of them come from the Anjanaharibe massif, where the species was discovered in the 1990s. On the basis of the specimens caught so far during the on-site investigations, it is assumed that the mountain small tenrek occurs relatively frequently.
Way of life
The way of life of the mountain small tenrec is largely unexplored. In terms of teeth and body structure, the animals show hardly any specializations. One individual was trapped in the root system of a smaller tree at the entrance to a cavity. Several pregnant females had between one and two embryos in the uterus . Depending on the stage of development, these measured between 3 and 30 mm, with the latter being about to give birth.
Systematics
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Internal systematics of the Kleintenreks according to Everson et al. 2016
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The mountain-Kleintenrek is a kind from the genus of microgale ( Microgale ) within the family of tenrecs (Tenrecidae). The Kleintenreks form together with the rice burrowers ( Oryzorictes ) and the representatives of the genus Nesogale the subfamily of the Reistenreks (Oryzorictinae). With more than 20 species, the Kleintenreks are considered to be the most diverse member of the entire family. They are considered to be more native within the Tenreks due to some morphological features. According to molecular genetic analyzes, the genus originated in the Lower Miocene , around 16.8 million years ago, and has diversified considerably since then. Today's representatives show adaptations to different ways of life, so there are forms that dig underground, live above ground, or tree-climbing and water-dwelling forms. A larger part of the Kleintenreks inhabit the humid forests of eastern Madagascar, a few species also occur in the drier landscapes of the western part of the island. Within the genus, different kinship groups can be identified both morphologically and genetically. The mountain Kleintenrek is closely related to the Taiva-Kleintenrek ( Microgale taiva ).
The first scientific description of the mountain small tenrec was made by Steven M. Goodman and Paulina D. Jenkins in 1998. It was based on seven individuals from the Anjanaharibe massif in northeast Madagascar . The type locality is located 11 km west-southwest of Befingitra in the Anjanaharibe Sud nature reserve and rises 1550 m above sea level. The holotype from there includes a fully grown female animal that Goodman himself picked up in mid-November 1994 as part of a field study in the nature reserve. The specific epithet monticola is of Latin origin and refers to the mountainous habitat of the animals.
Threat and protection
The mountain range Kleintenrek occurs in the 321 km² nature reserve Anjanaharibe Sud and around 600 km² Marojejy National Park . A currently not yet protected population exists on the western slope of the Anjanaharibe massif. The greatest threat to the existence of the small mountain tenreks is illegal logging, mainly for the extraction of rosewood , but also for fuel, which happens right into the nature reserves. Furthermore, slash and burn and the mining of precious stones have a negative effect on the populations . Since the species is only restricted to a narrow range of altitude in the mountainous zones, this can lead to its extinction in the near future. The IUCN therefore lists the mountain small tenrek in the “threatened” ( vulnerable ) category . Particular importance lies in the future research of the exact limits of the distribution area and above all the biology and ecology of the species.
literature
- Steven M. Goodman and Paulina D. Jenkins: The Insectivores of the Réserve Spéciale d'Anjanaharibe-Sud, Madagascar. Fieldiana Zoology 90, 1998, pp. 139-161 ( [2] )
- Paulina D. Jenkins: Tenrecidae (Tenrecs and Shrew tenrecs). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 134-172 (p. 167) ISBN 978-84-16728-08-4
Individual evidence
- ↑ a b c d e f Steven M. Goodman and Paulina D. Jenkins: The Insectivores of the Réserve Spéciale d'Anjanaharibe-Sud, Madagascar. Fieldiana Zoology 90, 1998, pp. 139-161
- ↑ a b c d e Steven M. Goodman and Paulina D. Jenkins: Tenrecs (Lipotyphla; Tenrecidae) of the Parc National de Marojejy, Madagascar. Fieldiana Zoology 97, 2000, pp. 201-229
- ↑ a b c Paulina D. Jenkins: Tenrecidae (Tenrecs and Shrew tenrecs). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 134-172 (p. 167) ISBN 978-84-16728-08-4
- ↑ Voahangy Soarimalala and Steven M. Goodman: Diversité biologique the micromammifères non volants (Lipotyphla et Rodentia) dans le complexe Marojejy Anjanaharibe-sud. In: Steven M. Goodman and Lucienne Wilmé (eds.): Nouveaux résultats faisant référence à l'altitude dans la région des massifs montagneux de Marojejy et d'Anjanaharibe-sud. Recherche pour le développement, Série Sciences biologiques, Center d'Information et de Documentation Scientifique et Technique 19, 2003, pp. 231-276
- ^ A b P. J. Stephenson, Voahangy Soarimalala and Steven M. Goodman: Microgale monticola. The IUCN Red List of Threatened Species 2016. e.T29462A97200712 ( [1] ); last accessed on July 17, 2016
- ↑ a b c Kathryn M. Everson, Voahangy Soarimalala, Steven M. Goodman and Link E. Olson: Multiple loci and complete taxonomic sampling resolve the phylogeny and biogeographic history of tenrecs (Mammalia: Tenrecidae) and reveal higher speciation rates in Madagascar's humid forests . Systematic Biology 65 (5), 2016, pp. 890-909 doi: 10.1093 / sysbio / syw034
- ^ JF Eisenberg and Edwin Gould: The Tenrecs: A Study in Mammalian Behavior and Evolution. Smithsonian Institution Press, 1970, pp. 1-138
- ^ RDE MacPhee: The Shrew Tenrecs of Madagascar: Systematic Revision and Holocene Distribution of Microgale (Tenrecidae, Insectivora). American Museum Novitates 2889, 1987, pp. 1-45
Web links
- Microgale monticola in the endangered Red List species the IUCN 2016 Posted by: PJ Stephenson, Voahangy Soarimalala and Steven M. Goodman, 2014. Accessed on 17/07/2016.