The Cochin forest cane turtle (''Vijayachelys silvatica''), also known as Kavalai forest turtle, forest cane turtle or simply cane turtle, is a rare

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

from the Western Ghats of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

. Described in 1912, its type locality is given as "Near Kavalai in the

Cochin Kochi ( , ), formerly known as Cochin ( ), is a major port city along the Malabar Coast of India bordering the Laccadive Sea. It is part of the district of Ernakulam in the state of Kerala. The city is also commonly referred to as Ernaku ...

State Forests, inhabiting dense forest, at an elevation of about 1500 feet above sea level".Henderson (1912) Only two specimens were found at that time, and no scientist saw this turtle for the next 70 years. It was rediscovered in 1982, and since then a number of specimens have been found and some studies have been conducted about its phylogeny and ecology.Praschag et al. (2006)

Taxonomy

The Cochin forest cane turtle belongs to the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Geoemydinae of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Geoemydidae The Geoemydidae (formerly known as Bataguridae) are one of the largest and most diverse families in the order Testudines (turtles), with about 70 species A species () is often defined as the largest group of organisms in which any two in ...

, formerly known as Bataguridae. It was once placed in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

'' Geoemyda'' and subsequently moved to '' Heosemys''. But it was found to be distinctive as a genus and related to '' Melanochelys'' and placed in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus, ''Vijayachelys'' in honor of the famous Indian

herpetologist Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (in ...

Jagannathan Vijaya Jagannathan Vijaya (1959–1987) was India's first woman herpetologist. She documented the movement of turtles all over the country and worked as an assistant to Edward Moll, the chairman of the World Conservation Union's Freshwater Chelonia ...

(1959–1987) who rediscovered this species in 1982 and until her death extensively studied it. A diagnosis of the

osteology Osteology () is the scientific study of bones, practiced by osteologists . A subdiscipline of anatomy, anthropology, archaeology and paleontology, osteology is the detailed study of the structure of bones, skeletal elements, teeth, microbone mo ...

of ''Vijayachelys'' was published in 2006.

Description

The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

is considerably depressed, with a prominent mid-line keel, as well as one less pronounced

lateral Lateral is a geometric term of location which may also refer to: Biology and healthcare * Lateral (anatomy), a term of location meaning "towards the side" * Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx * Lateral release ( ...

keel on each side. Its posterior margin is feebly reverted and not or only indistinctly serrated. The nuchal

scute A scute () or scutum (Latin: ''scutum''; plural: ''scuta'' "Scutum (shield), shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of Bird anatomy#Scales, birds. The ter ...

is small. The first vertebral scute is broader in front than behind and larger than the second, third and fourth vertebral shields. These are considerably broader than long, as broad as the costal scutes. The

plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...

is sizeable, being nearly as large as the shell opening; it is connected to the carapace by

ligament A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...

s and particularly in females there is little

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

between the shields of the shell. The plastron is angled at the sides and openly emarginate at the forward and aft opening. The width of the plastron bridge is less than the length of the hind lobe; the longest

median The median of a set of numbers is the value separating the higher half from the lower half of a Sample (statistics), data sample, a statistical population, population, or a probability distribution. For a data set, it may be thought of as the “ ...

suture is between the abdominal scute, the shortest between the gular scute. The axillary and inguinal scutes are very small; one of the latter is even absent. CaneTurtle DSC 4117

Its head is rather large, with a truncated snout as long as the sizeable

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

; the upper jaw is hooked, with small

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

e. The mandibular

symphysis A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together o ...

is very long, exceeding the maximum diameter of the orbit in width. On the hind part of the head, the skin is divided into moderately large shields. The

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

lacks a temporal arch and has the

frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...

extended to form a considerable part of the orbit. Seen from above, the prootic extends towards the front. The jugal does not contact the small laterally emarginated and medially constricted pterygoid process, the bones being separated by the maxilla and a gap. The triturating (chewing) surface of the upper jaw is long and narrow, more than four times as long as it is wide. The lower

temporal fossa The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines above, and the zygomatic arch below. Its floor is formed by the outer surfaces of four bones of the skull. The fossa is filled by the te ...

is large and strongly

concave Concave or concavity may refer to: Science and technology * Concave lens * Concave mirror Mathematics * Concave function, the negative of a convex function * Concave polygon A simple polygon that is not convex is called concave, non-convex or ...

, providing an attachment for the massive chewing muscle. The forelegs are covered in enlarged squarish or pointed horny scales, particularly on the front. The hindlimbs are rather club-shaped, the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

margins and anterior region of their heels bearing enlarged horny scales. The fingers are webbed one-third of their length, while the toes bear rudimentary webbing only. The tail is rather short and becomes very narrow behind the

cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...

in males; it is a mere stub in females. The carapace of the

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

was dark bronze; the plastron yellowish with two dark blotches on either side of the bridge. The jaws and upper front part of the head are bright yellow in the living animal, with a red spot on the top of the snout. The hind part of the head and the neck are brown. Limbs and tail are black. The length of the type specimen's shell is 120 mm, its breadth 83 mm and its depth 45 mm. Females are slightly larger than males, but this smallish turtle does not seem to exceed about 13 cm in carapace length even when fully grown.

Ecology

This turtle inhabits dense evergreen forest, presumably at lower elevations. According to the natives from whom Henderson obtained the type, the species inhabits short burrows underground and is indifferent about having water nearby (unlike some of its relatives, which are decidedly aquatic). The type as well as another younger specimen were kept in captivity for six months, and Henderson remarks that they did not show any special partiality for water and when handled did not emit the offensive odour known from the related Indian black turtle (''Melanochelys trijuga'').Smith (1941) The first captive specimens lived entirely upon vegetable food, but subsequently it has turned out that this turtle is

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

, eating any suitably sized plant and animal food.

Conservation

The Cochin forest cane turtle is listed as endangered (EN B1+2c v2.3) by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

and is listed in

CITES Appendix II CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...

. It is rarely found in the pet trade. The Kadar tribe people occasionally hunt the turtles for bush meat. Additional threats are posed by deforestation and planned hydroelectric projects. The turtles have a patchy distribution range but where they occur they can be found in relatively high densities. Still, this turtle is considered to be a rare species.Vijayachelys silvatica (Henderson 1912) – Cochin Forest Cane Turtle. In: Rhodin, A.G.J., Pritchard, P.C.H., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., and Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Deepak, V., Praschag, P., and Vasudevan, K. No. 5, pp. 078.1–7 Chelonian Research Monographs.

References

Sources cited