Research Article |
Corresponding author: Peter Praschag ( ppraschag@turtle-island.at ) Academic editor: Silke Schweiger
© 2022 Peter Praschag, Richard Gemel.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Praschag P, Gemel R (2022) A new subspecies of the Asiatic softshell turtle Amyda ornata (Gray, 1861) from its northern distribution range. Herpetozoa 35: 81-93. https://doi.org/10.3897/herpetozoa.35.e86055
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We describe a new subspecies of Amyda ornata (Gray, 1861) from the southeastern parts of Bangladesh (Chittagong hill tracts), adjacent regions of north-eastern India (Mizoram, Assam and Tripura) and Myanmar, based on morphological characteristics. The holotype comprises some skeletal elements held by the Natural History Museum of Vienna; the five paratypes consist of living specimens in the private collection of PP “Turtle Island” (a turtle conservation zoo in Graz, Austria). After the genetic identity had been determined in a previous investigation, the morphological description was carried out by examining living specimens and photo documents; and additionally, by evaluating the computed tomography of further living animals with exact location data.
Amyda ornata jongli ssp. nov. differs from the other Amyda ornata subspecies mainly by its relatively compact and stout head in subadults and adults, its paler, greyish and less contrasting colouration missing distinct bright yellow pigments, ochre-coloured irises, and the existence of more distinct tubercles in the neck region and in the posterior section of the carapace than both other subspecies of Amyda ornata. The tubercles along the front of the carapace protrude clearly in subadult and adult specimens. This softshell turtle is heavily exploited within its limited distribution. Therefore, special comments on conservation aspects are given together with a final discussion on distribution and systematics.
Amyda ornata jongli ssp. nov., Bangladesh, conservation, distribution, India, morphology, Myanmar, Reptilia, Testudines, Trionychidae, systematics
The base of a good conservation strategy requires an in-depth knowledge of the ecology and distribution of the considered taxa, as well as a thorough understanding of its taxonomy. In the case of endangered species which are extensively harvested across their range, this is especially relevant. To make plans for sustainable commercial use in the future, data on systematics, distribution, habitat preferences, population biology and reproduction must first be studied and assessed (
Initially, Amyda Schweigger in Geoffroy Saint-Hilaire, 1809 was recognised as a monotypic genus, consisting only of one species Amyda cartilaginea (Boddaert, 1770). It has become evident however, that it represents in fact a species complex (
Specimens: One skeleton and five living turtles from Sangu River near Dohazari. (CITES ex- and imports: 26/2013, 10/2015, AT 13-E 0057 and AT 15-E 0024).
The five living specimens were photographed, measured and weighed, and additionally scanned by computed tomography (CT). For reasons of comparison, computed tomography was also conducted on alcohol-preserved voucher specimens from the Natural History Museum Vienna, and additional living specimens from Schönbrunn Zoo, Vienna with known origin. CTs were conducted at the Department of Reproduction Management, Leibnitz Institute for Zoo and Wildlife Research, Berlin and was done along the coronal axis for a total of 505 slices. Each 1024×1024 pixel slice is 0.06822 mm thick, with an interslice spacing of 0.06822 mm and a field of reconstruction of 32 mm. Micro-CT scanning was performed with a phoenix|x nanotom m (GE Measurement & Control, Wunstorf, Germany) using a tungsten target at a voltage of 130 kV and a current of 80 μA for 29 minutes (1800 projections). 3D datasets were processed with VG Studio Max 2.2 software (Visual Graphics GmbH, Heidelberg, Germany); the data were visualized using the Phong volume renderer to show the surface of the skull and reflect a variety of different levels of x-ray absorption.
Known distribution records (Points 1–11) of Amyda ornata jongli ssp. nov., details see Table
Additionally, photo documents of turtles with reliable local data were studied and compared alongside our dataset.
Measurements of the paratypes, measurements (in cm), CL = Carapace length (straight length), CW = Carapace width (straight width at the broadest point = above hind legs), DL = Discus length (along median line), W = Weight (in kg).
Specimen | Date | Sex Juvenile (juv) Male (m) Female (f) | CL | CW | DL | W |
---|---|---|---|---|---|---|
NHMW 41463:1 | 09.02.2016 | M | 33.5 | 27.1 | 20.1 | |
NHMW 41463:1 | 26.04.2022 | M | 41.4 | 33.4 | 26.4 | 9.78 |
NHMW 41463:2 | 09.02.2016 | F | 37.5 | 30.5 | 22.3 | |
NHMW 41463:2 | 26.04.2022 | F | 42.0 | 34.8 | 27.4 | 10.21 |
NHMW 41463:3 | 09.02.2016 | F | 28.7 | 23.6 | 18.5 | |
NHMW 41463:3 | 26.04.2022 | F | 34.7 | 28.0 | 21.2 | 5.57 |
NHMW 41463:4 | 09.02.2016 | Juv | 22.1 | 18.7 | 15.0 | |
NHMW 41463:4 | 26.04.2022 | F | 33.6 | 27.2 | 21.6 | 5.07 |
NHMW 41463:5 | 09.02.2016 | Juv | 21.9 | 18.7 | 15.1 | |
NHMW 41463:5 | 26.04.2022 | F | 28.3 | 23.5 | 23.9 | 3.58 |
Order: Testudines Batsch, 1788
Family: Trionychidae Gray, 1825
Subfamily: Trionychinae Gray, 1825
Genus: Amyda Schweigger in Geoffroy Saint-Hilaire, 1809
Species: Amyda ornata (Gray, 1861)
Subspecies: Amyda ornata magnapapulae Hoser, 2021 nomen rejectum according to Turtle Taxonomy Working Group (TTWG, 2021).
NHMW 40278 (Natural History Museum Vienna, herpetological collection): subadult specimen; skull and lower jaw; incomplete postcranial skeleton: parts of discus, shoulder girdle, pelvic girdle and extremities (Figs
Sangu River near Dohazari, Chittagong hill tracts, south-eastern Bangladesh, don. P. Praschag 3/2016.
The paratypes consist of five living voucher specimens, one male and four females in the facility of “Turtle Island”, NHMW 41463: 1–5 (Fig.
The subspecies name jongli (noun in apposition) refers to the special term of local fishermen in Bangladesh who call this softshell turtle “jongli” in Bengali, deriving from “jangala” in Sanskrit. It means wild and ferocious, as the animals are powerful and struggle when captured. Simultaneously it means also “…coming from rivers of jungle woodlands”.
The Maximum Likelihood Tree for Amyda and related softshell turtles shows five distinct clades, divided into three species. Clades 4 (“Pale coloured, large nuchal and back tubercles” now herein described as A. o. jongli ssp. nov.), 5 (“Trionyx phayrei” / “Trionyx ephippium”) and 6 (“Trionyx ornatus”) show similar levels of genetic differentiation from each other, and constitute the three identified subspecies from Mainland Southeast Asia (
The heads in subadults and adults are stout (see Figs
The genus Amyda is distinguished from all other trionychids by the following suite of characteristics:
Carapace with black markings, sometimes black and yellow or bright dots, but no ocelli; skull: snout longer than the diameter of the orbit (more in juveniles than in adults); alveolar surface of the mandible with a longitudinal ridge at the symphysis; surface of jaws light; first and second neural fused; epiplastra in contact or narrowly separated, front part of epiplastra are elongated (see Fig.
A. ornata differs from A. cartilaginea (sensu stricto) and Amyda sp. (= candidate species A, sensu
Amyda o. ornata differs from the other two subspecies by its distinct yellow pigments on carapace, head and neck; the presence of a “crown”: two or three converging black lines forming an arrow on the upper side of the head; tubercles predominantly in the nuchal and front region of the carapace; saddle-shaped dark colouration on carapace uncommon. Distribution: Vietnam, Laos, Cambodia (Chaco Phraya, Irrawaddy and Salween River systems).
Amyda o. phayrei differs from the other two subspecies by its dull brown carapace, yellow pigments present forming distinct yellow dots on the head and neck; carapace with or without distinct saddle-shaped dark colouration; with eyes open, the eyelids have distinct yellow spots alternating with grey “zebra striped” colouration; tubercles in the nuchal and back region of the carapace but not as distinct as in A. o. jongli ssp. nov.; head in upper side view more slender and narrowed to the proboscis. Distribution: Thailand, Myanmar (delta region of the Irrawaddy (Ayeyarwady) and possibly neighbouring Salween (Thanlwin) river, NE India (Mizoram) and Yunnan (
(Fig.
Point (pt) | Locality | Coordinates (WGS 84) (Latitude, Longitude) |
---|---|---|
1 | Dohazari (Terra typica), Bangladesh | 22.163958, 92.065016 |
2 | Sangu River – CHT, Sangu-Matamuhuri Reserve Forest, Bangladesh ( |
21.3455827, 92.6069887 |
3 | Thanchi upazila, Bandarban, Bangladesh ( |
21.8217887, 92.4377149 |
4 | Matamuhri river, Bangladesh (village Nr. 1 in Fig. |
21.8830881, 92.2497277 |
5 | Ngengpui River, Ngengpui wildlife sanctuary, Lawngtlai, Mizoram, India (central point selected for map) | 22.43134, 92.7867 |
6 | Sangu River at Remarki, Fatik Chhari, border to Myanmar, Bangladesh | 21.3030315, 92.6511433 |
7 | Durung Khal River, mouth of the Halda river, Bangladesh | 22.7612597, 91.755951 |
8 | Tuirial River drainage, Aizawl District, India ( |
23.555, 92.779 |
9 | Narichera Stream, tributary of Khowai River, North District, Tripura, India ( |
23.7804, 91.8430 |
10 | Dhalchera, Phaisen Hills, Cachar district, India ( |
24.264611, 92.415256 |
11 | Guwahati, Assam - Fish market, India ( |
26.16945, 91.76448 |
India: Mizoram: Ngengpui River, Ngenpui Wildlife Sanctuary, Lawngtlai (Pawar and Choudhuri 2000): bony disc deposited in the holdings of the Museum of Bombay Natural History Society under BNHM 1446 as confirmed by Rahul Khot, Curator of National History Collection department of the Bombay Natural History Society (pers. comm. 7th, April 2016) (Fig.
Tripura: Narichera Stream, North District (
Assam: Dhalchera river, Phaisen Hills, Cachar District (
The area registered in the distribution records comprises two main river systems separated by a watershed running through the centre part of Mizoram: the southern region in southern Mizoram and Chittagong hill tracts containing Sangu River as a part of the “Kolodyne Basin” and draining in the Bay of Bengal. The northern part is situated in northern Mizoram Assam and Tripura and is dominated by the Barak River system (“Barak Basin”) draining into the Brahmaputra; in the recent past a specimen was even reported from the fish market in Guwahati, Assam (Fig.
The given characteristics and diagnostic features should enable the distinction of this subspecies from the two other currently recognised subspecies of A. ornata, as well as from A. cartilaginea sensu stricto, although it will not be possible to assign single specimens in every case due to the intraspecific variability of the species, the ontogenetic changes and the anthropogenic transport/translocation of numerous specimens in the past. Distinct colour patterns on the carapace with black marks as described above for A. o. jongli ssp. nov. and/or a vertebral stripe may appear in different populations of Amyda including A. ornata too, but not as consistently as in A. o. jongli ssp. nov. Trionyx ephippium, described by
As shown by
Softshell turtles are closely connected to freshwater systems. As shown by
Most of the rivers originate in the central part of Mizoram and flow either southwards or northwards, corresponding to the north-south directed mountain and hill chains. The main northerly flowing rivers of Mizoram are Tlawng, Tut, Tian, Tuichawng, Tuirial, Tuivawl, Teirei, Tuirini, and Serlui. The largest of these is the Tlawng (Dhaleshwari) with a length of about 185 km. The Tlwang, Tuirial and Tuivawl Rivers drain into the Barak River directly. All other rivers meet the Barak River through indirect and subsidiary channels either via Tripura-Bangladesh or via Manipur. Ultimately, the northerly flowing rivers of Mizoram, drain into the Barak River and constitute a part of the “Barak Basin”. The Barak River, in due course drains into “Brahmaputra” as its left bank tributary (
The Kolodyne Drainage System is formed of the south flowing rivers, with the Kolodyne River originating in the central state of Myanmar and draining into the Bay of Bengal southward to Sittwe (
The Sangu River flows through Myanmar and Bangladesh, its source is in the North Arakan Hills of Myanmar and forms the boundary between Arakan and the Chittagong Hill Tracts. It follows a northerly circuitous course in the hill tracts and then enters Bangladesh near Remarki, Thanchi Upazila, Bandarban District, from the east. It flows north through Thanchi, Rowangchari and Bandarban Sadar Upazilas of Bandarban District. It then flows west through Satkania and Banshkali Upazilas in Chittagong District and flows into the Bay of Bengal near Chittagong, about 16 kilometres south of the mouth of the Karnaphuli River. Sangu drains off the waters of Patiya, Satkania, and Banshkhali Upazilas and has a connection with the Karnaphuli River through the Chand Khali River. A. o. jongli ssp. nov. has not been recorded in the Karnaphuli River. The Sangu is a shallow river, but it becomes violent during rains and develops rapid currents. Thus, the Sangu River System, along with the Karnaphuli River, form a river system that is neither connected in the north to the Brahmaputra, nor in the south to the Irrawaddy River system.
Based on the out-dated taxonomic concept, the IUCN Red List categorises “Amyda cartilaginea” (species group as a whole including A. ornata as “synonym”) as vulnerable (
As the first reports of occurrence of Amyda in Bangladesh were only published in 2013 for the first time (
Softshell turtles in general, and Amyda especially, are heavily exploited for consumption over almost all parts of their distribution (
The distinct taxonomic position of A. o. jongli ssp. nov. correlates with distribution patterns of other trionychid and aquatic geoemydid turtles in that the Arakan mountains form the eastern border of the roofed turtle genus Pangshura, as well as for the semiaquatic Geoemydid genus Melanochelys. The Arakan mountains separate also the sister species Chitra indica (Gray, 1831) from Chitra vandijki McCord & Pritchard, 2003, as well as Lissemys punctata andersoni Webb, 1980 from Lissemys scutata (Peters, 1868).
Interestingly, however, in the case of Morenia petersi (Anderson, 1879) and Morenia ocellata (Duméril & Bibron, 1835), the Arakans do not form a natural barrier, as M. ocellata can be found both east and west of these mountains, with M. petersi just to the west.
Computed tomography was performed by Guido Fritsch, Department of Reproduction Management of the Leibnitz-Institute for Zoo and Wildlife Research, Berlin, under the leadership of Thomas Hildebrandt on 15. November 2016. Both authors are indebted to Thomas Hildebrandt and Guido Fritsch for producing and disposal of the turtle reconstruction by computer tomography; additionally, we thank Michaela Gumpenberger (Assistant Professor at the Clinical Unit of diagnostic Imaging, University of Veterinary Medicine Vienna) for computed tomographies of further Amyda specimens for comparison, Walter Joyce (Professor of Université de Fribourg, department of Geosciences) for making available a rich image material of Amyda skeletons for comparisons, Rupali Gosh for her support in the field, Madeleine Wheatley for her help in editing the article and creating the data map. Thanks to Silke Schweiger, Christoph Leeb and Georg Gassner for support at the Natural History Museum Vienna.