Jenkins-Kleintenrek
| Jenkins-Kleintenrek | ||||||||||||
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| Microgale jenkinsae | ||||||||||||
| Goodman & Soarimalala , 2004 |
The Jenkins-Kleintenrek ( Microgale jenkinsae ) or Jenkins-Kleintanrek is a species of mammal from the genus of Kleintenreks within the Tenreks family . It is a smaller representative of the Kleintenreks and is characterized by a spindle-shaped body with agouti-like fur and an elongated head with a narrow snout. The tail exceeds the length of the rest of the body, which means that the species is related to other long-tailed lesser tenreks. So far only two individuals have been recorded that come from dry forests in southwestern Madagascar . Little is known about the way of life of the animals. It was first described in 2004. The species is classified as critically endangered.
features
Habitus
The Jenkins-Kleintenrek is one of the smaller representatives of its genus. So far, however, it has only been recorded for two non-fully grown individuals who are not yet fully grown. Although they have already largely reached the size of the old animals and their coat texture, their teeth are still in the change of teeth, which limits the informative value somewhat. The animals have a head-trunk length of 5.9 and 6.2 cm and a tail length of 7.9 and 8.1 cm, making the tail slightly longer than the rest of the body. The body weight is between 4.9 and 5.3 g. In appearance, the Jenkins Kleintenrek is similar to other Kleintenreks. The body is spindle-shaped, the legs are short and sturdy and the head is characteristically narrow and pointed at the front. The fur on the back has an agouti- like pattern from the ears to the tail and on the sides , which is caused by a mixture of completely black or yellowish-brown hair. Other hairs are yellowish brown along the shaft and have a black tip. Overall, the fur is dense and soft, the individual hairs are 4 to 5 mm long. Guide hairs are predominantly grayish in color. The agouti-like drawing extends to the front of the eyes, while the head is dominated by lighter shades of color that vary between light yellowish-brown and silver-white. The fur on the underside is light, the hair is predominantly gray at the base and white at the tip. The transition from the back to the peritoneum stands out prominently on the sides, but does not form a clear line, but rather runs gradually. The vibrissae are either black or beige-white, partly black at the base and beige-white at the tip. They measure 20 mm around the mouth and 5 mm around the nose. The ears are comparatively long at 18 mm. The shell is colored brown and covered inside and outside with a fine, silver fur. The skin of the tail is black-brown on the top and pale brown on the underside, the transition is highlighted on the sides by a clear dividing line. The skin is covered by a very fine, silvery fur that becomes thicker towards the end of the tail. One of the two individuals is characterized by a black and white pattern. The front and rear feet each have five rays. The top of the limbs is also covered with white fur, on the hind feet tufts of hair protrude over the claws. The length of the hind feet is 14 to 15 mm, which is quite large. The first ray is only a third of the length of the second, while the fifth is two thirds of the fourth. The second and fourth rays are almost the same length.
Skull and dentition features
The skull is relatively short and laterally flattened. The greatest length is 18.7 and 18.8 mm, respectively, and on the expansive cranium it reaches a width of 8.2 and 8.4 mm. There is a slight constriction behind the eyes. The rostrum is also short and tapers towards the front. The nasal bones are, however, long with almost 9 mm length. In the back area, on the parietal bones and on the occiput , the skull is clearly rounded, the occipital bulge appears to be very weakly developed. The glenoid pit for engaging the mandibular joint forms only a slight indentation. The lower jaw itself has a slender structure, the crown process is narrow and points backwards, the angled process is short and also narrow.
With the exception of the molars , only the deciduous teeth from Jenkins-Kleintenrek have survived. Overall, the dentition does not appear very robust, the rows of teeth in the front section of the dentition converge to one another, in the rear section they run almost parallel. There is a noticeable diastema between the two front incisors in the upper and the middle two premolars in the lower dentition . The first two incisors of the upper and lower rows of teeth are relatively large, the last incisor is rather small. All incisors have several cusps, with the first and third cusps in the upper dentition being bicuspid , while the middle one has a tricuspid crown. The canine tooth in both the upper and lower row of teeth in turn reaches the size of the two front incisors. The molars are typically zalambdodont , so they have three conspicuous cusps on the chewing surface. The last molar in the upper jaw is greatly reduced in size, in the lower jaw all three molars are roughly the same size. The length of the upper row of teeth is 8.2 mm, that of the lower 8.0 mm.
distribution
The Jenkins-Kleintenrek is only known from a single site in southwest Madagascar . This is located in the Forêt des Mikea in the province of Toliara , about 17 km inland on the Mozambique Strait and 9.5 km west of Ankiloaka, between Morombe in the north and Manombo in the south. It rises about 80 m above sea level. The area is characterized by transitional vegetation from dry, deciduous forests to thorny bush landscapes. Accordingly, the climate is rather dry with around 400 to 500 mm of precipitation per year. The two previously known individuals of the species were caught in the forests, which are composed of Dalbergia and trees of the genera Commiphora and Hildegardia with heights of growth of 10 to 15 m. The undergrowth is dense and consists of bushes interspersed with plants of the genus Xerophyta from the group of the Velloziaceae and milkweed plants . Further investigations in the Forêt des Mikea with similar habitat conditions have so far not produced any evidence of representatives of the species. It is therefore classified as extremely rare. The extent of the previously known distribution area is only 1.64 km².
Way of life
The way of life of the Jenkins-Kleintenrek can be regarded as almost unexplored. The structure of the feet suggests an animal moving on the ground. Both individuals were found in the rainy season and were not fully grown. In general, the wetter season is considered to be the breeding season in the dry regions of Madagascar due to the richer food supply.
Systematics
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Internal systematics of the Kleintenreks according to Everson et al. 2016
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The Jenkins Kleintenrek is a kind from the genus of microgale ( Microgale ) within the family of tenrecs (Tenrecidae). The Kleintenreks belong to the subfamily of the Reistenreks (Oryzorictinae), in which in turn the rice burrowers ( Oryzorictes ) and the representatives of the genus Nesogale are to be placed. With more than 20 species, the Kleintenreks form the most diverse member of the family, and due to some morphological features they are considered to be more originally within the Tenreks. According to molecular genetic analyzes, the genus was formed in the Lower Miocene around 16.8 million years ago and diversified considerably in the period that followed. Today's representatives are adapted to different ways of life, so there are forms that sometimes dig underground, live above ground, or tree-climbing and water-dwelling forms. The greater part of the Kleintenreks is native to the moist forests of eastern Madagascar, a few species also inhabit the drier landscapes of the western part of the island. Within the genus, different kinship groups can be identified both morphologically and genetically. The Jenkins-Kleintenrek is close to a group of long-tailed Kleintenreks; from a molecular genetic point of view, the Little Long-tailed Kleintenrek ( Microgale longicaudata ) is the closest relative of the Jenkins-Kleintenrek.
The Jenkins-Kleintenrek was first described scientifically in 2004 by Steven M. Goodman and Voahangy Soarimalala . The two individuals who were available for this were caught in the Forêt des Mikea in mid-February 2003 . The field research at that time comprised a total of six investigation sites in the forest area, but the species was only detected at one point. A non-adult male animal represents the holotype ; the individual is 14.3 cm long and weighs 4.9 g. The specific epithet jenkinsae honors the biologist Paulina D. Jenkins from the Natural History Museum in London, who made a major contribution to the systematics of the Tenreks and who herself described several species.
Threat and protection
The location of the two previously known individuals corresponded to a forest that was slightly influenced by anthropogenic influences, but has since been cleared. Similar habitats, in which potential representatives of the Jenkins lesser tenrec could occur, are located a few kilometers further south of the type locality. Possible threat factors for the animals can be found in the overprinting of landscapes by agriculture and in natural bushfires. The Forêt des Mikea is now part of a state reserve. The IUCN classifies the species as "critically endangered" ( endangered ) a. In principle, field studies on the distribution, biology and possible adaptability of the Jenkins lesser tiger are necessary.
literature
- Steven M. Goodman and Voahangy Soarimalala: A new species of Microgale (Lipotyphla: Tenrecidae: Oryzorictinae) from the Forêt des Mikea of southwestern Madagascar. Proceedings of the Biological Society of Washington 117 (3), 2004, pp. 251-265 ( [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. 172) ISBN 978-84-16728-08-4
Individual evidence
- ↑ a b c d e f Steven M. Goodman and Voahangy Soarimalala: A new species of Microgale (Lipotyphla: Tenrecidae: Oryzorictinae) from the Forêt des Mikea of southwestern Madagascar. Proceedings of the Biological Society of Washington 117 (3), 2004, pp. 251-265
- ↑ a b 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. 172) ISBN 978-84-16728-08-4
- ↑ Voahangy Soarimalala: Les Afrosoricides de la forêt sèche malgache. Afrotherian Conservation 8, 2011, pp. 4-9
- ^ A b P. J. Stephenson, Voahangy Soarimalala and Steven M. Goodman: Microgale jenkinsae. The IUCN Red List of Threatened Species 2015. e.T62015A97192062 ( [1] ); last accessed on July 2, 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
- ↑ Martin Nicoll and Nanie Ratsifandrihamanana: The growth of Madagascar's protected areas system and its implications for tenrecs (Afrosoricida, Tenrecidae). Afrotherian Conservation 10, 2014, pp. 4-8
Web links
- Microgale jenkinsae in the Red List of Threatened Species of IUCN 2016 Posted by: PJ Stephenson, Voahangy Soarimalala and Steven M. Goodman, 2014. Accessed on 07/02/2016.