Río San Román.--A river flowing northward in south-central El Petén to the Río Salinas (Usumacinta). We collected along the river at a place about 16 kilometers north-northwest of Chinajá, approximately at Lat. 16° 10´, long. 90° 17´, elev. 110 m. In the dry season the river was clear; it is surrounded by rainforest.
Sayaxché.--Lat. 16° 31´, long. 90° 09´, elev. 80 m. A town on the southern bank of the Río de la Pasión. Specimens were obtained in the rainforest and in cleared areas in the immediate vicinity of the town.
Toocog (formerly Sojío).--Lat. 16° 41´, long. 90° 02´, elev. 140 m. A camp of the Ohio Oil Company of Guatemala located at the rainforest-savanna edge, 15 kilometers southeast of La Libertad. Although we collected on the savannas as well as in the forest, especially to the east of the camp, only species obtained in the forest are considered in this report.
In presenting an account of the herpetofauna of southern El Petén three items need to be considered: (1) The composition of the fauna; (2) the ecology of the fauna; (3) the relationships of the fauna. Each of these topics is discussed briefly below. Logically a discussion of the origin of the fauna should follow, but this is being withheld for inclusion in a report on the herpetofauna of the entire El Petén by L. C. Stuart and the author; at that time the above topics will be expanded to cover the herpetofauna of the whole region.
TABLE 1.--COMPOSITION OF THE HERPETOFAUNA IN SOUTHERN EL PETÉN, GUATEMALA.
=============+============+============+============ Group | Families | Genera | Species -------------+------------+------------+------------ Gymnophiona | (1)[A] | (1) | (1) Caudata | 1 | 1 | 2 Salientia | 6 | 10 (1) | 19 (1) Crocodilia | 1 | 1 | 1 Testudines | 4 | 7 | 8 Sauria | 6 | 13 (1) | 19 (1) Serpentes | 4 | 21 (7) | 29 (10) +------------+------------+------------ Total | 22 (1) | 53 (10) | 78 (13) -------------+------------+------------+------------
[Footnote A: Numbers in parenthesis indicate the number of additional taxa that probably occur.]
A total of 78 species of amphibians and reptiles has been found in the rainforests in southern El Petén; a break down into families and genera is given in table 1. Another 13 species probably occur in southern El Petén (see Hypothetical List of Species). The fauna primarily is composed of typical humid lowland forest inhabitants, such as: