McCord's snake necked turtle

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McCord's snake necked turtle
McCord's neck turtle at the Lisbon Zoo

McCord's neck turtle at the Lisbon Zoo

Systematics
Order : Turtles (Testudinata)
Subordination : Turn-Neck Turtles (Pleurodira)
Family : Snake neck turtles (Chelidae)
Subfamily : Chelodininae
Genre : Australian snake neck turtles ( Chelodina )
Type : McCord's snake necked turtle
Scientific name
Chelodina mccordi
Rhodin , 1994

McCord's snake neck turtle ( Chelodina mccordi ) is an extremely endangered species of turtle that occurs in two subspecies on the island of Roti ( Pulau Roti in Indonesian ) and with one subspecies on neighboring Timor . It belongs to the genus of the Australian snake neck turtle ( Chelodina ) in the family of the snake neck turtle(Chelidae). The two subspecies on Roti are acutely threatened with extinction due to hunting for the international illegal animal trade and the shrinking habitat. McCord's snake neck turtles on Timor live mostly in East Timor's only national park .

habitat

On the left is a map of the original distribution of McCord's snake necked tortoise on Roti. The type locality of C. m. mccordi is located in Busalangga, in the center of the island (orange). The type locality of C. m. Roteensis is located in the northeast on Danau Oendui, on the Tapuafu Peninsula. [2] On the right a map of the waters and places in the municipality of Lautém (East Timor) with the presumed distribution of McCord's snake-necked tortoise (orange). The type locality of C. m. timorensis is located on the west bank of Lake Ira Lalaro. She also lives in the tributaries of the lake and on the Irebere in the administrative office of Iliomar in the southwest. [3] On the left is a map of the original distribution of McCord's snake necked tortoise on Roti. The type locality of C. m. mccordi is located in Busalangga, in the center of the island (orange). The type locality of C. m. Roteensis is located in the northeast on Danau Oendui, on the Tapuafu Peninsula. [2] On the right a map of the waters and places in the municipality of Lautém (East Timor) with the presumed distribution of McCord's snake-necked tortoise (orange). The type locality of C. m. timorensis is located on the west bank of Lake Ira Lalaro. She also lives in the tributaries of the lake and on the Irebere in the administrative office of Iliomar in the southwest. [3]
On the left is a map of the original distribution of McCord's snake necked tortoise on Roti. The type locality of C. m. mccordi is located in Busalangga, in the center of the island (orange). The type locality of C. m. Roteensis is located in the northeast on Danau Oendui , on the Tapuafu Peninsula. On the right a map of the waters and places in the municipality of Lautém (East Timor) with the presumed distribution of McCord's snake necked tortoise (orange). The type locality of C. m. timorensis is located on the west bank of Lake Ira Lalaro . She also lives in the tributaries of the lake and on the Irebere in the Iliomar administrative office in the southwest.

The originally known habitat of McCord's snake necked turtle extended to three separate regions with a total of 200 km² on Roti, previously possibly even over all lakes and swamps of the island, so that eastern and western populations also met one another. The largest area in terms of area was in the southwest and central highland plateau of the island. The humidity is moderate here. The turtle was sparsely found a little further to the southwest, also in the lower plains. Another occurrence was in the northeast of Roti, in the interior of the Tapuafu peninsula , around the Danau Oendui ( Lake Enduy ) and near the peninsula on the southern shore of the Bay of Korobafo . At times it was speculated that they were each dealing with separate populations. It is now assumed that the animals in the two north-eastern areas belong to the same population. In the brackish water of the coasts and in the mangrove forests of the island, the species has not yet been detected. None of the areas on Roti are under special protection. In the meantime the turtle has been exterminated in many places, elsewhere it only occurs marginally and only wanders through certain areas. The total area of ​​the areas on Roti inhabited by intact populations should be less than 20 km².

Flooded lagoons at Ira Lalaro . The habitat of
McCord's snake necked turtle

In 2008, viable populations of McCord's snake necked turtles were found only in four locations on Roti. In the southwest they live near the Danau Peto , around the Danau Toea and Danau Anak lakes and in some of the small lakes around Busalangga . In the northeast the turtles can only be found around the Danau Oendui, but here too they are on the verge of extinction. There is another stock at Danau Undun , near the large Usipoka salt lake . In other places on the island, at best, there are no longer viable residual populations and individual animals.

In Timor, the snake-necked turtle occurs in the East Timorese lake Ira Lalaro in the extreme east of the island, in the surrounding rivers and wetlands, around the town of Lospalos and in the plains of the Irebere River in the Iliomar administrative office .

In the rainy season, the turtle lives in shallow, permanent and semi-permanent, eutrophic lakes, swamps and adjacent rice fields. On Timor it could also be seen in rivers and streams. No individuals have so far been found in the short-lived flowing waters of the rainy season on Roti. The turtle can also be seen regularly on the streets and in open terrain, provided it has rained heavily the day before. It does not survive the dry season in the mud, but retreats into tall grass or under leaves and rocks when its water dries up. Otherwise it rests in the shrinking lakes.

description

Parts of the carapace in an individual of the nominate form C. m. mccordi

The carapace (armor on the back) is oval, wide and slightly fluted. It is usually 150 to 214 mm long and the neck is about the same length. McCord's snake-necked tortoise has no axillary and inguinal shield plates. The first marginal disk is always smaller than the second. The females are usually larger than the males, around 11% in the subspecies C. m. mccordi , up to 15% in C. m. redensis . The largest female measured so far, which was caught in Zentralroti, reached a shell length of 241 mm. In return, the heads of the males are relatively a little wider, the tail base is broadened and their tails are a little longer. There are no other particular external differences between males and females of the same size. A female caught on Timor in 2014 weighed 2340 g, specimens kept there as domestic animals weighed 498 to 1660 g.

The color of the carapace is light gray-brown to olive-green. But some specimens also have rust-colored spots. The plastron (belly shell) is pale yellow-white. In the Timor subspecies, there are yellowish-white and brown-red / white-spotted color variants of the plastron. The soft tissues are light to dark gray on the upper side, the underside is yellowish white. The top of the head of the eastern subspecies on roti is brown, occasionally black. The side of the head, lower jaw and underside of the head are creamy yellow, the neck and other soft tissues are gray-black above and yellowish-white below as usual. The carapace is significantly darker, from chocolate brown to black, with a reddish discoloration on the sixth to eighth marginal plates. The plastron of the subspecies is yellowish with black discolorations along the grooves of varying degrees. The neck is littered with round tubercles . The irises of the western subspecies on roti are black and surrounded by a white ring. Those of the subspecies on Timor are light to dark brown with a yellow ring and the irises of the eastern subspecies on Roti are yellow with a gray ring. Front and rear legs each have four claws.

Taxonomy and systematics

Initial description

The first specimens were caught on roti by the Dutchman Herman Frederik Carel ten Kate in 1891 and viewed in 1895 by the zoologist Theodoor Gerard van Lidth de Jeude as an isolated population of the New Guinea snake necked turtle ( Chelodina novaeguineae ). Some of ten Kate's original catches and other specimens that entered the international pet trade in the 1970s and 1980s were examined in 1994 by Anders GJ Rhodin , director of the Chelonian Research Foundation in Lunenburg, Massachusetts , and newly described as a distinct species. McCord's snake necked turtle was named after William Patrick McCord , a veterinarian and turtle expert from Hopewell Junction , New York . In 2007 the description of two subspecies of Roti and East Timor followed.

External system

McCord's snake-necked turtle belongs to the subgenus Chelodina of the Australian snake-necked turtle, along with Pritchard's snake-necked turtle ( C. pritchardi ), which resembles it, the smooth-backed snake-necked turtle ( C. longicollis ) and the slightly more differentiated New Guinea-necked turtle and Reimann's long-necked turtle ( C. reanni ) . However, electrophoretic studies indicate that the New Guinea snake necked turtle and Reimann's snake necked turtle are closest relatives of McCord's snake necked turtle. Because of its osteology , C. canni is also included in this group. The subgenus Chelodina is distinguished from the subgenus Macrochelodina by relatively narrow heads, shorter necks and wider breast plates.

The skull of McCord's snake necked turtle is relatively broad and robust compared to its closely related species, similar to that of Pritchard's snake necked turtle. Only the New Guinea snake-necked tortoise and Reimann's snake-necked tortoise have, on average, even stronger skulls and the heads of the species of the subgenus Macrochelodina are wider. These differ significantly from McCord's snake-necked tortoise in the shape of the skull. Overall, this is larger than the New Guinea snake-necked turtle, slightly smaller than Pritchard's snake-necked turtle and significantly smaller than C. canni . What is striking about McCord's snake-necked turtle is the difference in length of the inner edge between the first and second marginal shield. The first shield is proportionally much smaller than the second. In C. canni the first marginal shield has a size of 71% of the second shield, in the Western Australian snake -necked tortoise ( Chelodina steindachneri ) it is 77%, in the New Guinea snake-necked tortoise 80%, in Reimann's snake-necked tortoise 90%, in the smooth-backed snake-necked tortoise 103% and in Pritchard's neck turtle 109%. In McCord's snake necked turtle, it is only between 47 and 62.5%, depending on the subspecies. Sorting the breast plates of the plastron according to their length results in McCord's snake-necked turtle: Intergular> Abdominal> Anal> Femoral> Pectoral> Gular. For Pritchard's snake necked turtle, Pectoral ≥ Femoral, New Guinea snake necked tortoises have both Pectoral> Femoral and Femoral> Pectoral and for C. canni Anal> Abdominal.

Internal system

The "Timor Turtle": In the picture below you can see how it retracts its neck in case of danger.
Differences between C. m. mccordi and C. m. timorensis
differences C. m. mccordi C. m. redensis C. m. timorensis
Width of the carapace in% of the length 79% 78.2% 72.6%
Average width of the first marginal shield
in% of the average width of the second marginal shield		 47% 76.9% 62.5%
Furrows on vertebral shields 2–4 No Yes Yes
Neck plate protruding from the armor (nuchal) No No Yes
Shallow furrow in the middle of the carapace on large specimens only in females - Males and females
The pectoral plate usually ends at the marginal shield ... ... No. 5, rarely on the border between 5 and 6 ... No. 5 ... No. 6, rarely on the border between 5 and 6

After the nominate form Chelodina mccordi mccordi , which was first discovered on Roti, a subspecies was described for the first time in 2007 with C. mccordi timorensis (partly in older literature also as Chelodina mccordi timorlstensis ) from eastern Timor, which shows some characteristics of the New Guinea snake-necked tortoise. The carapace of the "Timor Turtle" is oval with slight extensions on the sixth to eighth marginal shield. The fourth to seventh marginal shield is slightly curved in specimens larger than 164 mm. The supracaudal shield is slightly serrated and has a slight adjacent cavity on the eleventh marginal shield. On the second to fourth vertebral shields there are longitudinally light ridges, as well as on the fifth vertebral shield, which occurs in some specimens. The neck shield ( nuchal ) is long and broad towards the back. In contrast to C. m. mccordi, something about. The dividing line between the pectoral plate and the abdominal plate ends in the Timor tortoise mostly at the sixth marginal shield, sometimes at the border between the fifth and sixth marginal shield and only rarely at the fifth marginal shield. At C. m. mccordi , the dividing line almost always runs towards the fifth marginal shield, rarely towards the boundary between the fifth and sixth marginal shield. The soft tissues of the Timor Turtle are similar to those of the nominate form.

Scientists first discovered the Timor Turtle in February 2003 in the village of Malahara . Based on photos of this animal, the discovery was identified as a McCord's snake necked turtle. Further research trips confirmed the assessment that it was an endemic subspecies living on Timor . The turtles with a white plastron are called Fataluku Veu ("turtle"), Pai Veu ("pig turtle" ) or Veu Ratenunu (queen turtle) by the locals , those with a red Sepe Veu . They are considered to be two separate species among the population, whereby the different colors should arise from the different habitat. The Veu therefore lives in shallower waters. The generic, local name is Veu Mani Lohai (long-necked turtle ). According to reports from local people, there is also a variant with a short neck called Veu Akanara (“servant tortoise ”) or Veu Manikava (“short-necked tortoise ”). If you hold both turtle shapes together, the "servants" should be bitten to death by the "queens". However, scientists have not yet found a specimen with a short neck. It may be the Chinese three-keeled tortoise ( Mauremys reevesii ) introduced by humans .

The exact assignment of the Timor tortoise was not initially certain and led to fierce controversy between various research groups. Some authors regard it as a separate species and refer to it as Chelodina timorensis . Others see them only as "divergent island forms of the same kind".

A few months after describing the Timor Turtle, McCord et al. 2007 with Chelodina mccordi redensis another subspecies. Since it lives in the two distribution areas in the northeast, C. m. roteensis in English literature "Eastern Iceland Roti Snake-Necked Turtle", known as C. m. mccordi , with the larger population in central Rotis, is known as the "Western Roti Island Snake-Necked Turtle". The holotype is preserved in alcohol in the American Museum of Natural History. It is an adult female that was caught by locals in Danau Oendui. There is also a paratype , an adult male from the same lake, in alcohol. The skull of C. m. Roteensis is stronger than that of the other subspecies, even more robust than that of most of the other species of the subgenus. Is exceeded C. m. rotensis only from the females of Reimann's snake necked tortoise and of C. canni from the population from eastern Queensland . On masseter masseter there are a few small, elevated, irregular scales. The parietal shield is relatively narrow in the subspecies in relation to the head. The gradually larger tubercles on the head form a row, the muzzle is blunt and beveled. The neck is 60 to 70% of the length of the back armor ( C. m. Mccordi : 58 to 65%) and has occasional tubercles that appear rounder and more prominent than in the nominate form. The color deviations from the other subspecies are particularly noticeable. The eastern subspecies is darker, partly black, with a reddish sheen on the sixth, seventh and eighth marginal plates. With a maximum length of 220 mm, the egg-shaped, slightly wrinkled carapace from C. m. rotensis smaller than the rounder of C. m. mccordi . The carapace of the eastern subspecies has its widest point at the seventh marginal shield. In addition to the slight groove in the middle of the carapace that adult animals often have, almost every adult C. m. Roteensis has a slight keel instead of or in addition to the groove. In the nominate form, this keel only occurs occasionally. Growth rings are missing. The neck plate reaches a length of 8% compared to the entire carapace. The marginal plates at positions 4 to 7 are bent upwards at the edge, the twelfth plate is raised in the middle, above the tail. The sixth marginal plate is narrower than in the nominate form. The fifth vertebral shield is not found in all specimens of McCord's snake neck turtles. Unlike the other vertebral shields, it is longer than it is wide. The length of the plastron in relation to the width is the shortest of the entire subgenus (about 2: 1).

Reproduction and way of life

McCord's snake neck turtle in Karlsruhe Zoo

The information about when McCord's snake necked turtle lays its eggs in the wild has only come from observations by local people.

In Timor, turtles lay their eggs in the dry season (July to October). Occasionally it is reported that there is a second oviposition, either shortly before the rainy season or in February, when the water is already receding. The nests are in the bank mud and in swamps. You can recognize them from the outside as small holes in the mud, the imprint of the breastplate of the female and a small mound.

Up to three clutches per year are given for the subspecies on roti. As a rule, 7 to 16 eggs are laid here in the dry season between February and September. The size of the oval eggs is 27.5 to 35.0 mm × 18.5 to 20.5 mm and the weight is 8 to 10 g. They resemble the eggs of the smooth-backed snake-necked turtle and those of Pritchard's snake-necked turtle, but are slightly larger. The eggs of Reimann's snake-necked tortoise are even larger, but their shape is much more rounded. During the day the clutch has a temperature of 29 to 32 ° C, at night it is 24 to 36 ° C. The young hatch after 66 to 122 days at the end of November at the beginning of the rainy season. When hatching, they are usually 23 to 29 mm in size. However, once a young animal was discovered in the wild, whose growth rings suggested a hatch size of 32 mm. After the first season it reached 51mm and at the end of the second it reached 73.5mm. No growth rings can be seen in adult animals. Freshly hatched animals have yellow spots on the plastron, which become darker over time, until the plastron is almost completely black after a few weeks. As they grow up, the color becomes paler again until they finally reach the yellow-white color of adults.

Judging by the skull, McCord's snake-necked turtles are carnivores and fish-eaters . The food spectrum includes small fish, tadpoles (but not frogs), insects and other small animals. Despite their large local presence, snails do not seem to be one of them in the wild, even if they are not spurned as food in captivity, along with fish (live and dead), worms and meat.

Danger

A swimming specimen of McCord's neck turtle at Columbus Zoo, Ohio . The webbed feet are clearly visible between the claws.

McCord's neck turtle ranks eleventh on the IUCN list of the 25 most critically endangered freshwater turtles in the world as of 2007.

The turtle's habitat is shrinking to roti. Swamps and other wetlands have increasingly been converted into rice fields, so much of the original habitat has disappeared. In addition, deforestation, erosion and decreasing rainfalls caused wetlands to disappear as a result of climate change. Although the turtle also populated the rice fields, it was easier for animal traders to catch them there. The use of fertilizers and pesticides could also have had a negative impact on the population. Since the early 1970s, Roti turtles have been exported to Jakarta via Kupang for the international trade of exotic animals . The turtle is no longer eaten on Roti, as it was around 1900. It's not supposed to taste good and reminds locals too much of snakes. Sometimes the turtle is killed out of dislike precisely because of this resemblance. The population in Central Roti appeared to be stable until the 1990s, although the effects of trapping were noted. But after McCord's snake necked turtle was identified as a separate species, the numbers in all known populations decreased sharply. Although legal trade from Indonesia was restricted in 1997 and completely banned since 2001, and this species has been protected under Appendix II of the CITES Agreement since 2004 , it appears that it is still caught for international trade. A local who catches these turtles makes $ 100 per animal. This is more than an annual income on Roti. The species is almost extinct on the island. Where it was once common, it is now rarely, if at all, to be found.

The region around the Timorese Ira Lalaro belongs to the Nino Konis Santana National Park , but the turtles are also caught here, be it as pets for children or as food. They cost between two and four US dollars in local markets, although foreign dealers have not yet appeared. Unlike the hunt for crocodiles, hunting for turtles is not taboo. However, targeted hunting is ritualized and limited to particularly dry years when the water level of the Ira Lalaro falls sharply. Such years are increasing due to climate change. Wet years, like 2012 and 2013, in which the hunting parties do not take place and the population can recover, are becoming rarer. After all, the owner of the lake has issued a hunting ban in recent years because he expects the turtles to benefit economically. The crocodiles, who are considered to be the ancestors of humans , would have ordered Vicente Araújo to ban them. However, it is not followed by all residents of the region, although violations can lead to belief in disease. The traditional hunts take place once or twice within a dry year. 20 to 30 animals can be caught in each village. They are either simply picked up on land or the hunters poke at the animals in the water with a bamboo stick. Outside of the rainy season, turtles are often caught from canoes with fishing lines.

Water buffalo trample the tall grass where the turtles hide. In addition, the grass for pastures is burned down.

The introduction of the Chinese three-keeled turtle, kept as pets, and the increasing distribution of the black- scarred toad ( Bufo melanostictus ) threaten the population. Water buffalo and cattle also change the turtle's habitat; Pigs and dogs rob nests. In 2014, Suco Muapitine reported a general decline in the number of turtles. This is due to the growing populations of humans and saltwater crocodiles as well as the hunting and fire in the region. The fires are usually kindled to get fresh grass for grazing animals. If the turtles do not die in the fire, they are easily spotted by predators on the burned-down surfaces. In Suco Mehara , locals observed an increase in turtles in some cases, since hunting for them has decreased since the creation of the national park and more eggs and young animals are growing up. Most of the Timorese surveyed assume a reduction in the turtle population.

As a measure to counter the decline in populations, Australian biologists, in collaboration with East Timorese authorities in Tetum, have published a children's book for schools, which aims to bring children closer to the rare turtle and its protection. 250 copies and 100 teacher's copies were distributed in Mehara and in the parish capital of Lospalos. There is also the idea of ​​breeding McCord's snake neck turtles in captivity. In addition, one would like to redesign traditional hunts in such a way that the population only marks the animals and then releases them again so that further data can be collected for the protection of the turtles.

On Roti, researchers are urgently calling for a protected area, for example on the Tapuafu peninsula with the lakes Usipoka, Undun and Oendui and the surrounding, untouched wetlands of Tanjung Pukuwatu . Because of the high biodiversity of this area, animal species still unknown to science could be found here. One could also imagine a relocation of the turtle species to other areas of the island. In the USA and Europe, the first successes in breeding McCord's snake-necked tortoise have already been achieved.

Legends

In Timor, it is said that the turtle emerged from a snake that sought refuge from a dog under a coconut shell.

literature

Web links

Commons : McCord's snake-necked turtle ( Cheluodina mccordi )  - Collection of images, videos and audio files

supporting documents

literature

Individual evidence

  1. ↑ WWF: Background information on McCord's snake-necked tortoise , March 2007 , accessed January 7, 2015.
  2. ↑ a b c d e Rhodin et al. 2008, p. 008.3.
  3. ↑ a b Kuchling et al. 2007, p. 215.
  4. ↑ a b McCord et al. 2007, p. 58.
  5. ↑ a b c Rhodin et al. 2008, p. 008.4.
  6. ↑ a b c d e f g Eisemberg et al. 2014, p. 4.
  7. ↑ a b Rhodin et al. 2008, pp. 008.5-008.6.
  8. ↑ Eisemberg et al. 2016, pp. 70 and 73.
  9. ↑ a b Eisemberg et al. 2014, p. 18.
  10. ↑ a b Eisemberg et al. 2014, p. 21.
  11. ↑ a b c Rhodin et al. 2008, p. 008.5.
  12. ↑ a b Kuchling et al. 2007, p. 214.
  13. ↑ a b c d e f Kuchling et al. 2007, p. 216.
  14. ↑ a b c McCord et al. 2007, p. 59.
  15. ↑ McCord et al. 2007, p. 61.
  16. ↑ Eisemberg et al. 2016, p. 70.
  17. ↑ a b c d e Kuchling et al. 2007, p. 217.
  18. ↑ Eisemberg et al. 2016, p. 72.
  19. ↑ a b Eisemberg et al. 2014, p. 17.
  20. ↑ a b McCord et al. 2007, p. 60.
  21. ↑ a b Rhodin et al. 2008, p. 008.2.
  22. ^ Turtles of the World, 2012 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution, and Conservation Status , accessed January 3, 2015.
  23. ↑ According to data in the table and photos of the holotype in: McCord et al. 2007, p. 60 f.
  24. ↑ Kuchling et al. 2007, p. 213.
  25. ↑ a b c Eisemberg et al. 2016, p. 74.
  26. ↑ a b Eisemberg et al. 2014, p. 24.
  27. ↑ Hinrich Kaiser et al., PhD, Department of Biology, Victor Valley College: The herpetofauna of Timor-Leste: a first report. , accessed January 3, 2015.
  28. ↑ William P. McCord et al. 2007: A New Species of Chelodina (Testudines: Chelidae) from Eastern Timor Island (East Timor) . Reptilia 52, 58-61.
  29. ^ Government of Timor-Leste: Prime Minister officially launches the new stamp models for Timor-Leste , November 28, 2010 , accessed January 3, 2015.
  30. ^ A b Georges, Arthur, Thomson, Scott: Diversity of Australasian freshwater turtles, with an annotated synonymy and keys to species. Pp. 15-16, Zootaxa 2496: 1-37, 2010, accessed January 3, 2015.
  31. ↑ McCord et al. 2007, pp. 59 to 61.
  32. ↑ a b c d e Eisemberg et al. 2014, p. 22.
  33. ↑ a b Rhodin et al. 2008, p. 008.6.
  34. ↑ a b Eisemberg et al. 2014, p. 19.
  35. ↑ Eisemberg et al. 2014, p. 23.
  36. ↑ Eisemberg et al. 2016, pp. 69 and 74.
  37. ↑ Eisemberg et al. 2014, p. 8.
  38. ↑ Eisemberg et al. 2014, p. 20.
  39. ↑ Rhodin et al. 2008, p. 008.1.
  40. ↑ Rhodin et al. 2008, p. 008.7.
This version was added to the list of articles worth reading on January 8, 2015 .