Dryad-Kleintenrek
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| Jenkins , 1992 |
The Dryad-Kleintenrek ( Microgale dryas ), sometimes also Dryad-Kleintanrek , is a species of mammal from the genus of Kleintenreks within the Tenreks family . It lives in the rainforests of north-eastern Madagascar , but has only been found at a few sites and is very rare. Like all Kleintenreks, the animals are characterized by a spindle-shaped body, strong legs and a long and narrow head tapering to a point. The tail is relatively short, characteristic of the Dryad-Kleintenrek are the flattened shafts of the leading hairs. Little is known about the way of life. The first scientific description of the species comes from 1992, its existence is threatened.
features
Habitus
The Dryad-Kleintenrek represents a medium-sized representative of the Kleintenreks. The head-torso length of four examined individuals from the Ambatovaky reserve was 10.6 to 11.1 cm, the bulwark was 6.8 to 7.1 cm long and is thus significantly shorter (60 to 67%) than the rest Body. The weight varied from 38 to 40 g. In appearance, the Dryad-Kleintenrek resembles, like the other Kleintenreks, a shrew , characteristic is the spindle-shaped body with the short, strong limbs and the narrow, pointed head. The back fur is dark reddish or grayish brown with a gray tinge. The individual hairs have gray bases, the shaft is light brown or reddish brown in the upper area. Some hair has black tips. In contrast, the shafts of the guide hairs appear colored black. In contrast to other small tenreks, these are flattened roughly in the middle of the shaft and broadened in cross-section, only becoming round again towards the tip. On the ventral side, the hair is colored gray at its bases and light gray at the top. The overall darker back color merges on the sides with the lighter fur color on the underside. The tail is colored uniformly gray. The tops of the forefeet and hind feet are gray-brown, the undersides are lighter on the front feet than on the hind feet. Both the hands and the feet each have five rays, each with claws. The central claw on the forefoot is significantly enlarged and elongated. The length of the rear foot is 18.1 to 18.7 cm. Its middle claw reaches about 65 to 79% of the length of the middle claw of the forefoot.
Skull and dentition features
The skull is long and graceful, the greatest length is 30.4 to 31.0 mm, the greatest width on the brain skull is 11.2 to 11.6 mm. The rostrum has a long, narrow and slightly robust construction, in the area of the anterior premolar (P2) it is only about 3.5 mm wide. The skull narrows somewhat in the area of the eyes, the side edges are somewhat dented when viewed from above. The posterior section of the skull is elongated and relatively high. On the elongated lower jaw, the horizontal bone body is slightly curved, the crown process protrudes relatively far upwards. In addition, the extension is quite wide. The mental foramen lies below the leading edge of the second premolar. The dentition consists of 40 teeth along the dental formula is: . Overall, the bit appears to be relatively robust. In the upper row of teeth, there are clear diastemas from the front incisor to the second premolar (P3) , which can be very wide, especially in the rear area. In the lower jaw there are generally shorter tooth gaps from the second incisor to the second premolar. The front teeth all have additional cusps on the crown of the tooth, with usually only small side cusps behind the main cusp. There is also a small anterior cusp on the lower canine. The first premolar in each case in the upper and lower dentition is large and robust. The molars are similar to those of the other Kleintenreks. They have a zalambdodonte chewing surface structure with three main cusps. The length of the upper row of teeth is 15.2 to 15.6 mm.
distribution
The Dryad Kleintenrek is endemic to a smaller area in northeast Madagascar . However, he is known there from a total of less than 10 localities, which are spread over three find regions. The main find area is in the reserve Ambatovaky in the province Toamasina , where the species was observed for the first time in 1990. Another find from the Anjanaharibe-Sud reserve on the Anjanaharibe massif in the Antsiranana province could also belong to this species. This was to some skull fragments of a young animal, which in a 1994 Gewölle the Red Owl was found due to the nature of the finds the assignment is not entirely clear. The third discovery area is in the Forêt de Makira , a 3860 km² forest area south of the Anjanaharibe massif and west of the Masoala National Park . The first sightings of the Dryad Kleintenreks took place here in 2003. The total distribution area is estimated at around 10,000 km². The animals predominantly inhabit the tropical rainforests of the low and middle altitudes of around 500 to 940 m above sea level. Very few individuals are known to date. The species is considered rare.
Way of life
Almost nothing is known about the way of life of the dryad lesser tiger. It is forest dwelling and possibly lives partly underground.
Systematics
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Internal systematics of the Kleintenreks according to Everson et al. 2016
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The Dryad 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). In addition, the Kleintenreks form the most diverse member of the Tenreks with more than 20 species. Due to some morphological features, they are also considered to be more originally within the family. According to molecular genetic analyzes, the genus originated in the Lower Miocene around 16.8 million years ago, and it diversified very strongly in the period that followed. 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 large part of the Kleintenreks live in the damp forests of eastern Madagascar, a few species are also found 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 Dryad-Kleintenrek is externally very similar to the Cowan-Kleintenrek ( Microgale cowani ) and the Grazilen Kleintenrek ( Microgale gracilis ), from a genetic point of view, the Naked-nosed Kleintenrek ( Microgale gymnorhyncha ) is the closest relative.
The Dryad-Kleintenrek was first described scientifically in 1992 by Paulina D. Jenkins . She used four individuals from the Ambatovaky forest in north-eastern Madagascar . The animals had been collected two years earlier, in February 1990, during a scientific expedition in the primary rainforest of the region at an altitude of 600 to 750 m above sea level. The Ambatovaky forest area represents the type region of the species. The holotype is represented by a fully grown female. The specific epithet dryas refers to the Greek word δρυας for the dryads , forest or tree nymphs of Greek mythology .
Threat and protection
The existence of the Dryad Kleintenreks is endangered by tree felling in connection with forestry use and the creation of arable or building land, which leads to a decline in the quality of the habitat. In addition, the species is only known from a few localities in a relatively small distribution area. The IUCN therefore lists them as "endangered" ( vulnerable ). Currently, the Dryad Kleintenrek occurs in two protected areas, the Ambatovaky reserve and the Anjanaharibe-Sud reserve . A third is to be set up in the Forêt de Makira . For the further protection of the animals, studies on taxonomy, distribution, ecology and almost all aspects of their way of life are necessary.
literature
- Paulina D. Jenkins: Description of a new species of Microgale (Insectivora: Tenrecidae) from eastern Madagascar. Bulletin of the British Museum (Natural History) 58 (1), 1992, pp. 53–59 ( [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 Paulina D. Jenkins: Description of a new species of Microgale (Insectivora: Tenrecidae) from eastern Madagascar. Bulletin of the British Museum (Natural History) 58 (1), 1992, pp. 53-59
- ↑ 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
- ↑ Steven M. Goodman and Paulina D. Jenkins: The Insectivores of the Réserve Spéciale d'Anjanaharibe-Sud, Madagascar. Fieldiana Zoology 90, 1998, pp. 139-161
- ↑ Zafimahery Rakotomalala, Vonjy Andrianjakarivelo, Volatiana Rasataharilala and Steven M. Goodman: Les petits mammifères non volant de la forêt de Makira, Madagascar. Bulletin de la Société zoologique de France 132, 2007, pp. 205-221
- ↑ a b c P. J. Stephenson, Voahangy Soarimalala and Steven M. Goodman: Microgale dryas. The IUCN Red List of Threatened Species 2016. e.T13356A97191108 ( [1] ); last accessed on August 13, 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 dryas in the endangered Red List species the IUCN 2016 Posted by: PJ Stephenson, Voahangy Soarimalala and Steven M. Goodman, 2015. Accessed August 13, 2016th