FAMILY CHELIDAE TURTLES FAUNA PARAGUAY

FAMILY CHELIDAE - TURTLES
Seven Paraguayan species in this family classified into four genera. Chelids are characterised by the presence of a cervical scute (present in all but one genus). The number of neurals is reduced with 7 or less present (completely absent in some). There are 9 plastral bones and the mesoplastra is absent. On the skull the temporal arch and quadratojugal are lacking and the prefrontals are not in contact. The palatals are separated by a vomer. The mandible is slender and weak and the neck incompletely retractile - frequently it is curved to the side and tucked under the lip of the carapace for protection. The fifth and sixth cervicals are amphicoelous and none are saddle-shaped. They are aquatic or semi-aquatic turtles typical of marshy and riverine habitats.

Key to Adults of Paraguayan Turtles

1a Extended neck greater than half the length of carapace. No chin barbels. Black bordered light stripe runs from upper jaw along neck. ..................................................................................................... Hydromedusa tectifera
1b Extended neck less than half length of carapace. Chin barbels present (though may be small) .................... 2

2a Carapace flattened or mildly domed. Lateral marginals of carapace obviously narrowed. ........................... 3
2b Carapace flattened. Snout blunt, not pointed. Lateral marginals of carapace not obviously narrowed .............................................................................................................................................................. Phrynops 5

3a Carapace mildly domed with low medial groove. Broad head and neck considerably shorter than carapace. Nose pointed. Eye with lateral bar. Often aggressive. Small barbels. ............................ Mesoclemmys vanderhaegei
3b Carapace flattened with shallow medial groove. Broad head and long neck. Eye without lateral bar. Barbels present and dorsal surface of head bears tubercles. ..................................................................... .Acanthochelys 4

4a Carapace length <18cm. Wide yellowish medial stripe on head bordered by two paler greyish stripes, clearly defined. Legs yellow. ................................................................................................... Acanthochelys pallidipectoris
4b Carapace length up to 24cm. Head uniformly dark greyish-brown above and yellowish below, with zone of demarcation ill-defined. Limbs grey on the outside, yellow underneath. ..........................Acanthochelys macrocephala

5a Dorsal surface of head mostly pale with dark lateral and dorsal stripes. Plastron pale with dark vermiculations on each plate.................................................................................................    Phrynops geoffroanus
5b Dorsal surface of head dark. Plastron uniformly pale or with large dark blotches. Not vermiculated. ......... 6

6a Head dorsally dark, ventrally pale, with dark longitudinal line running from the snout, through the eye to the rear of the head and large dark blotches on underside of neck. Carapace uniformly dark with yellow edges. Plastron yellow with large dark blotches on each plate...............................................................   Phrynops hilarii
6b Head dorsally and ventrally dark with thin yellowish lateral lines on sides of head. Carapace dark brownish, ornamented with black radial lines. Plastron uniformly yellowish or yellowish-brown, lacking conspicuous darker markings. ......................................................................................................................   Phrynops williamsi

REFERENCES
Fouquette MJ (unpublished) - Synopsis of Recent Reptiles to Genus - Arizona University
McCord WP, Joseph-Ounmi M, Lamar WW 2001 - A Taxonomic Reevaluation of Phrynops (Testudines: Chelidae) with the Description of Two New Genera and a New Species of Batrachemys - Revista Biologia Tropical 49: p715-764.
Whitfield P Ed.1984 - Longman Illustrated Animal Encyclopedia - Guild Publishing, London.