Designed by Paul Smith 2006. This website is copyrighted by law.
Material contained herewith may not be used without the prior written permission of FAUNA Paraguay.
Photographs on this web-site were taken by
Paul Smith, Hemme Batjes, Regis Nossent,
Alberto Esquivel, Arne Lesterhuis, Josť Luis Cartes, Rebecca Zarza and Hugo del Castillo and are used with their permission.
Containing the vast majority of Paraguayan snakes, the Microorder Macrostomata is made up of two Gigafamilies Booidea (including only the Boidae) and Caenophidia (for the other three families). Macrostomatans have an elongated mandible and quadrate and a supratemporal bone with a free posterior end. The ventral scales are wide, distinctly larger than the dorsals and a brille (spectacle) is usually present.

The Gigafamily Booidea is represented in Paraguay by one family, the Boidae. Members of this gigafamily have a vertical pupil and possess a brille. The hypapophyses are well-developed anteriorly and usually reduced posteriorly - though they are prominent on the entire spinal column in some. Vestiges of the pelvic girdle are usually present, some species having spurs in males which are formed by vestiges of the hind limbs. The maxilla and premaxilla do not meet, but the nasals and pre-frontals are in contact. Both the maxilla and pterygoid are toothed in all species, whilst the premaxilla is toothed only in some. Coronoid usually present. There are usually no tubercles on the scales.

The remaining three families of snakes in Paraguay - the Colubridae, Elapidae and Viperidae - all belong to this Gigafamily, and all are also members of the Superfamily Colubroidea. They possess a single carotid artery on the left side, the right being absent. The intercostal arteries arise at intervals of several body segments. The parasphenoid usually forms part of the border of the optic foramen. There are no teeth on the premaxilla and no coronoid bone in the lower jaw. There is no vestige of either the pelvic girdle or limbs.

Colubroideans have ventral scales about as wide as the body scales. The head scales are usually a few large, regular shields, though they are small in numerous in some species. Other characteristics vary with the individual taxa.

Fouquette MJ (unpublished) - Synopsis of Recent Reptiles to Genus - Arizona University
Whitfield P Ed.
1984  - Longman Illustrated Animal Encyclopedia - Guild Publishing, London.