Agkistrodon taylori
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Agkistrodon taylori |
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| Scientific name | ||||||||||||
| Agkistrodon taylori | ||||||||||||
| Burger & Robertson , 1951 |
Agkistrodon taylori is a species of snake from the subfamily of pit vipers . A German name has not yet been established; in German-speaking countries it is sometimes referred to as "Taylor's Moccasin Otter" or " Tamaulipas Moccasin Otter". It is endemic to northeast Mexico .
description
Agkistrodon taylori is a medium-sized, powerful snake with a relatively long tail. The total length is usually between 64 and 90 cm, the previously known maximum length of 96 cm. The tail accounts for an average of 17.7% of the total length in males and 15.2% in females.
Scaling
Like all species of the genus, the species usually shows 9 large, symmetrical shields on the top of the head. The parietals , however, are often fragmented into several smaller scales, particularly towards the end of the tail (posterior). The number of supralabials is 7 to 9, the number of infralabials 9 to 12.
The back scales are arranged in 23, very rarely in 21 longitudinal rows in the middle of the body. The number of abdominal scales ( ventral shields ) varies in males between 127 and 137, in females between 130 and 138, the number of subcaudalia between 45 and 56 in males and 40 to 47 in females.
coloring
The basic color of the upper side is variable pale gray, brown or reddish brown, on the flanks this color usually changes to orange. On the upper side of this basic color there are 11–16, an average of 13 brown, gray or blackish transverse bands, which are irregularly bounded by diagonally running, white, yellowish or yellow-orange rows of spots. Old, large individuals, especially males, are often almost solid black.
The head is very striking. The head sides show two parallel, wide, light (mostly yellow) stripes. The upper lateral stripe of the head runs from the anterior tip of the rostral along the canthus to the rear over the edges of the internasalia , the prefrontalia and the supraocularia and then from the upper postocularia over the second horizontal row of the temporalia . It then bends downward and often merges with the rear end of the lower head side strip. This is significantly wider than the upper one and begins at the tip of the snout, one of the nasals or at the foremost supralabial scale and then runs over the supralabial to the rear to the front or penultimate supralabial. Then the lower side strip bends downwards and then continues backwards. In contrast to the very similar Mexican moccasin otter , this lower side stripe in A. taylori covers the entire lower outer edge of the supralabialia, so it is not darkly limited downwards in front of the edge of the jaw.
With regard to the coloration, adult animals show a clear sexual dimorphism . Males are more inconspicuously colored; if any, the bright colors are limited to the lower flanks. The top of the head, cheek strips and transverse ligaments are usually black, the latter becoming orange at best on the lower flanks. The light stripes on the head are pale yellow, with a pale orange tinge on the upper lip. Females show a contrasting back markings with alternating black and lighter cross bars, the latter often with lots of yellow, red-brown or orange. The skull and cheeks are usually dark gray or reddish brown.
distribution and habitat
The species is endemic to northeast Mexico . The small distribution area covers most of the southern half of the state of Tamaulipas , extends further in a corridor through the central east of Nuevo León to near Monterrey , to the north of San Luis Potosí , to the northeast of Hidalgo and the North of Veracruz .
A. taylori inhabits grasslands with mesquites , thorn bush forests and tropical deciduous forests. Most of the finds were far from water on or near rocky hill slopes with many exposed limestone cliffs.
Systematics
The species only received species status in 2000, before it was listed as a subspecies ( A. bilineatus taylori ) of the Mexican moccasin viper ( Agkistrodon bilineatus ). It is named after the American herpetologist Edward Harrison Taylor , the first description (as a subspecies) was in 1951 by Burger and Robertson.
Way of life
The species is mainly observed at dusk and at night, only during the day on cloudy or rainy days. The main seasonal activity falls in the months of October to March, i.e. in the relatively cool and humid winter of the region.
The diet has been apparently hardly been studied so far were locusts that the sting pocket mice belonging Liomys inornatus and the white-footed mouse found as prey.
Reproduction has also hardly been studied. Mating has so far only been observed in winter in the months of November to February; comment fights for the females take place between the males . A. taylori , like all species of the genus, is viviparous ( ovoviviparous ). Litters of 3, 5, 8, 9, 9 and 10 pups were found between May and September. 20 newborn animals had a total length of 21.9-27.0 cm, a mean 23.8 cm and weighed 11.0-14.7 g, mean 13.0 g.
Investigations on the maximum age of wild animals are not available; in captivity one animal reached an age of 15 years and 7 months.
Existence and endangerment
There are no reliable data on the size of the total population and the population trend. Habitat destruction, the use of the habitat for cattle breeding and the extraction of nature for keeping reptiles are considered possible hazard factors. The IUCN therefore does not rule out population declines, but considers the species as a whole to be safe ("least concern").
swell
Individual evidence
- ↑ Christopher L. Parkinson, Kelly R. Zamudio, Harry W. Greene: Phylogeography of the pitocket clade Agkistrodon: historical ecology, species status, and conservation of cantils. Molecular Evolution 9 (4), 2000; Pages 411-420. doi : 10.1046 / j.1365-294x.2000.00854.x .
- ^ WL Burger, WB Robertson: A new subspecies of the Mexican moccasin, Agkistrodon bilineatus. Univ. Kans. Sci. Bull. 34, 1951: pp. 213-218
literature
- Jonathan A. Campbell , William W. Lamar: The Venomous Reptiles of the Western Hemisphere . Comstock; Ithaca, London. 2004. ISBN 0-8014-4141-2
Web links
- Agkistrodon taylori in the endangered Red List species the IUCN 2008. Posted by: Cox, N., Chanson, JS & Stuart, SN (Global Reptile Assessment Coordinating Team), 2007. Retrieved on October 14 of 2008.
- Agkistrodon taylori in The Reptile Database