Müller, 1935
Savannah side-necked turtle
Recognition
This is one of the smaller species of Podocnemis, with a recorded carapace length of 36 cm. The adult carapace is oval, very flattened, not broadened posteriorly, and has a smooth marginal rim with a slight cervical indentation. Adults usually lack a medial keel although a low one is found in juveniles. Vertebrals are broader than long and the 5th is posteriorly expanded. In adults, the carapace is olive to brown, but that of juveniles is brown with dark seams and a narrow yellow border. The plastron is large but does not completely cover the carapacial opening. Its anterior lobe is rounded in front and broader than the posterior lobe, which tapers toward the rear and has a posterior notch. The broad bridge is wider than the posterior lobe. The plastral formula normally is: abd > fem > pect > intergul >< an > gul > hum. The intergular is long and completely separates the gular scutes. Plastron and bridge are yellowish with some faded dark blotches. The broad head has a protruding snout and medially notched upper jaw. Three denticulate ridges occur on the triturating surface of the maxilla. Premaxillae are short, do not extend to the choanal rim, but join with the vomer to separate the maxillae. Foramina incisiva are located entirely within the premaxillae, but are almost hidden by extensions of the triturating ridges. The tympanum is as broad as the orbit. The interparietal scale is elongated, but the parietals still meet behind it. Large subocular scales and two chin barbels are present. The head is gray to brown; large yellow spots on the interorbital groove and tympanum are pronounced in juveniles. The jaws are yellow, and the neck and limbs gray. Three large scales occur on the posterior margin of the hind foot.
There are 28 chromosomes; 6 large to medium-sized metacentric and submetacentric chromosomes, 4 large to medium-sized subtelocentrics, 14 small to very small metacentrics and submetacentrics, and 4 small acrocentrics and subtelocentric (Rhodin et al., 1978).
Males have longer, thicker tails than do females and retain more of the juvenile head pattern.
Distribution
Podocnemis vogli lives in the Orinoco drainage in the llanos of Venezuela and adjacent Colombia. It is rumored also to exist in the upper Rio Yari, Caquetá, Colombia, a fact which, if true, places P. vogli in the Amazon drainage as well (William W. Lamar, pers. comm.).
Habitat
Podocnemis vogli inhabits small streams, rivers, swamps, and isolated ponds, often in heavily settled regions.
Natural History
The nesting season lasts from October to March and the nests may be dug considerable distances from water, in clayey savannah soils. One clutch comprises 5-20 (13-15) eggs, and three clutches are produced each season (Vanzolini, 1977; Pritchard, 1979; Ramo, 1982). The eggs have brittle calcareous shells and are elliptical (37-48 x 21-29 mm) (Pritchard and Trebbau, 1984). Hatchlings emerge from the nest in late April and May, and one we measured had a carapace length of 43 mm.
Podocnemis vogli is omnivorous, feeding on aquatic plants as well as small aquatic invertebrates, insects, amphibians and fish. Juveniles were observed feeding on capybara (Hydrochoerus hydrochaeris) faeces (Trepte, 1993). Rhodin et al. (1981) reported that P. vogli practices neustophagia. P. vogli is predominantly diurnal and basks on sunny days.
IUCN Red List Status (1996)
Not listed.