Tanimbar python
| Tanimbar python | ||||||||||||
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Tanimbar python, xanthic |
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| Scientific name | ||||||||||||
| Simalia nauta | ||||||||||||
| ( Harvey , Barker , Ammerman & Chippindale , 2000) |
The Tanimbar python ( Simalia nauta , Syn .: Morelia nauta ) belongs to the family of the pythons (Pythonidae). The species was only separated from the amethyst python in 2000 . Practically nothing is known about the biology of these snakes, which apparently only live on the Tanimbar Islands .
description
Physique and length
The Tanimbar python is a delicate, very slim built python. The long tail can make up over 19% of the total length. The head is clearly set off from the neck and, in adult females, is clearly broadened. The eyes are on the sides of the head and are directed slightly forward. When viewed from above, the snout, which is typical of the species, is longer in males than in females. The round nostrils sit at an angle between the top of the head and the side of the head. In terms of mass and length, Morelia nauta is the smallest of all amethyst pythons. Although the species has so far only been able to be examined using relatively few individuals, females with a total length of 1.8 meters are already considered to be very large. The largest animal examined so far had a head-trunk length of 1.99 meters and a total length of around 2.4 meters and weighed 1.9 kilograms.
Scaling
The rostral (snout shield), which is only moderately visible from above, has, as with most pythons, two deep labial pits . The nostrils are each positioned in the middle of the large nasal (nasal shield). A clearly recognizable seam runs from the nostril to the rear edge of the shield. Towards the middle of the head, the nasals are separated by a pair of triangular internasalia (intermediate nasal shields ). From the tip of the snout along the midline of the top of the head, the internalsals are followed by a large, long front pair of prefrontalia (forehead shields), which are in contact with the large simple frontals (forehead shield) behind them . A smaller rear pair of prefrontalia is completely separated by the anterior prefrontalia, but as individual shields they also touch the frontal. Behind the frontal two to three pairs of large parietals ( parietal shields ) adjoin , of which the front is usually the largest. These four shields can also fuse in some individuals, or there can be a small to large interparietal in their common center . The occipital (occipital shield), which lies further towards the neck, is unpaired in most animals and significantly larger than the adjacent nuchealia (neck shield). Over the eyes is ever a large triangular Supraoculare (via eye shield). Preocularia (forehead shields) exist two, the upper one being usually twice as large as the lower one. There are three to four postocularia (back shields). Subocularia (under-eye shields) are absent in this species. On the side of the head between the eye and nostril there are Lorealia (rein shields) arranged in two rows . Of the 12 to 13 supralabials (shields of the upper lip), the foremost five have deep labial pits at their rear edge, the size of the labial pits decreasing towards the angle of the mouth. Supralabials 6 and 7 also touch the lower edge of the eye. Infralabials (lower lip shields ) there are 17 to 20, of which the foremost 2 are weakly recognizable and 6 to 8 posterior labial pits beginning between infralabials 8 to 10. In most animals, the chin pit consists of shield-less skin.
The number of ventralia (abdominal shields) varies between 298 and 309, the number of dorsal rows of scales in the middle of the body between 41 and 45. From the cloaca to the tip of the tail there are 96 to 103 subcaudalia (underside shields of the tail), of which the first is simple and the one behind the following are paired. The anal (anal shield) is undivided.
coloring
The Tanimbar Python comes in four different color morphs :
- Xanthic unpatterned, with a red-brown to dark red-brown body color.
- Xanthic pattern, also with a reddish brown to dark brown basic color and additional yellow to golden spots.
- Axanthic unpatterned, with a clay-colored to dark brown-gray body color.
- Axanthic pattern, also with a clay-colored to brown-gray dark basic color and additional white to gray-white spots.
Patterned animals are about as common as unpatterned, xanthic individuals, however, are much rarer than axanthic ones. There does not seem to be any intermediate stages between the individual forms.
On the back of patterned animals, a series of small, bright, round spots on the back with a diameter of up to four shields run on both sides of the spine. Some of these spots combine over the spine, forming thin transverse ligaments. A second series of bright, round spots runs along the upper edge of the flank. These spots, too, have a diameter of up to four shields and can merge into a multi-interrupted strip on the front half of the body. A third series of bright spots up to two shields long and four shields high runs along the lower edge of the flank. Usually there is a back, an upper flank and a lower flank spot on a fictitious line stretching from the back to the abdomen. The individual rows of spots are located along the body at about 3 shields apart. From the rearmost third of the body to the tip of the tail, the back, upper flank and lower flank patches merge increasingly transversely with one another and thus form bright rings over the entire upper side of the body. Unpatterned animals lack any trace of back patterning, only black speckles can appear. The underside of both patterned and unpatterned animals is monochrome white-gray. From the rear half of the body, the darker back color borders on the side edges of the abdominal shields. On the underside of the tail, black and white-gray shields alternate offset towards the middle.
The top and side of the head are unpatterned and correspond to the basic body color. In contrast to all other amethyst pythons, the shields on the top of the head are not outlined in dark circles. Lip and chin shields are light yellow in xanthic animals and white to white-gray in axanthic animals. The front lip shields are also surrounded by a dark line. The throat is uniformly white-gray. In all of them, including the unpatterned forms, a dark brown band runs behind the eye above the upper edge of the upper lip shields to the corner of the mouth. Typically, there is also a small light spot in front of the eye and a larger light spot behind the eye. In some individuals, the light spot behind the eye is elongated and forms a light border above the dark band of the posterior eye. The neck bands typical of other amethyst python species are consistently absent in this species. The iris is brown to brown-gray in axanthic animals, yellow to golden in xanthic representatives and has a lightened edge around the pupil. Axanthic animals have a dark gray-blue tongue with light gray tips, xanthic representatives have a dark blue tongue with pink tips.
Color change
The ontogenetic color change is only slightly pronounced in this species. Hatchlings are slightly darker in color than adults and appear in a dark reddish brown or brown. Subadult animals are also darker in color than sexually mature animals and have a higher-contrast coloration. In certain individuals, the back spots and the lower flank spots become less contrasting and more indistinct with increasing age, the upper flank spots, on the other hand, remain well preserved throughout their life. Axanthic, patterned animals can dramatically lighten their body colors within hours due to environmental influences and even transform the dark components into a light beige. The xanthic forms are capable of only a slight lightening. During the gestation and breeding season, females of all four color forms become very dark, sometimes almost completely black.
Systematics
The amethyst python was first described by Schneider in 1801 under the scientific name Morelia amethistina . In 1933, Stull assigned subspecies status to the Australian population as Morelia amethistina kinghorni . In 2000, Harvey et al. taking into account morphological, biogeographical and molecular genetic aspects, five distinct species: Morelia amethistina , Morelia kinghorni , Morelia nauta , Morelia clastolepis and Morelia tracyae . All of the amethyst pythons described so far inhabit spatially separated habitats ( allopatry ). It is assumed, however, that further species can be differentiated among the species described so far, some of which even inhabit the same areas ( sympatry ). This is particularly suspected in New Guinea and New Ireland .
It is believed that an ancient form of the amethyst python once lived on the emerging New Guinea. Millions of years ago, in a first phase, the islands of Halmahera and New Ireland separated from New Guinea by deep straits, which completely isolated the amethyst python populations there. During later ice ages , land bridges formed between New Guinea and neighboring islands as well as the Australian mainland due to the low sea level. In a second phase, amethyst pythons colonized the D'Entrecasteaux Islands , the Louisiade archipelago and Aru . Seram , Ambon , Yapen , the coastal islands of the Torres Strait and Northern Australia. In a third phase, these pythons were able to use driftwood to get from Aru to the neighboring island of Kai , and those from Yapen to the neighboring island of Biak . The Tanimbar Islands also never had contact with other land masses, which means that precursors of this population must also have colonized the islands by water. Since New Guinea also changed significantly geotectonically, the original form of the amethyst python could still differentiate itself locally.
These pythons are most closely related to the Boelen python ( Morelia boeleni ). The characteristic commonality of amethyst and Boelen pythons is the presence of at least two pairs of large apex shields. In 1984, Wells & Wellington proposed separating amethyst pythons from diamond pythons ( Morelia ) as an independent genus called Australiasis .
The genus name Australiasis is invalid, however, because the genus was described in a journal that does not carry out a peer review process. At the beginning of 2014, the generic name Simalia (Gray, 1849) was therefore introduced for a new genus composed of the Boelen python and the amethyst pythons.
According to Harvey et al. (2000) and Reynolds et al. (2014) as follows:
| Simalia |
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The Latin word nauta means sailor. Since the Tanimbar Islands were always surrounded by deep sea and there were never any connections to the Australian mainland or New Guinea, the species must have reached these islands on driftwood. It is for this reason that Simalia nauta was given this scientific name. Although the species did not develop genetically away from other species until late, it differs morphologically the most from all other amethyst pythons. It is the smallest and most delicate representative, has the fewest number of signs and has different colors.
swell
Individual evidence
- ^ RW Wells, CR Wellington: A classification of the Amphibia and Reptilia of Australia . Australian Journal of Herpetology, Supplementary Series, Issue 1, 1984 pp. 1-61, full text
- ↑ Hinrich Kaiser, Brian I. Crother, Christopher MR Kelly, Luca Luiselli, Mark O´Shea, Hidetoshi Ota, Paulo Passos, Wulf D. Schleip, Wolfgang Wüster: Best Practices: In the 21st Century, Taxonomic Decisions in Herpetology are Acceptable Only When Supported by a Body of Evidence and Published via Peer Review. In: Herpetological Review, 2013, 44 (1), 8–23 .. 44, 2013, pp. 8–23.
- ^ R. Graham Reynolds, Matthew L. Niemiller, Liam J. Revell: Toward a Tree-of-Life for the boas and pythons: Multilocus species-level phylogeny with unprecedented taxon sampling. Molecular Phylogenetics and Evolution, Volume 71, February 2014, Pages 201-213, doi: 10.1016 / j.ympev.2013.11.011
literature
- MB Harvey, DG Barker, LK Ammerman, PT Chippindale: Systematics of Pythons of the Morelia amethistina Complex (Serpentes: Boidae) with the Description of three new Species. Herpetological Monographs 14, 2000, pp. 139-185.