The Obligate Carnivorous Larvae of the Frog, Lepidobatrachus laevis (Leptodactylidae)

Abstract

The larval morphology and captive breeding of Lepidobatrachus laevis (Leptodactylidae, Ceratophryinae) from the Paraguayan Chaco is described. The larvae are obligate carnivores that swallow large, living prey whole. The larva has a large dorsoventrally flattened head with a beakless wide mouth. By means of buccal suction they can ingest tadpoles that are nearly equal to themselves in size. The chondrocranial cartilages are simple in comparison to microphagous larvae, and the chondrocranium is wider than long. Larval development is rapid, and some tadpoles reach metamorphosis in 20 d. The brachial chambers are like those of Type IV (Orton, 1953) larvae, but the paired branchial openings are lateral and different from the spiracles of other anuran larvae. The branchial chambers show asymmetrical development with the opercular fold closing the right branchial opening prior to the formation of the left branchial opening. The right branchial chamber reopens and the fully developed larva has two large symmetrical branchial openings. The digestive tract is adult-like and the stomach has a large fundic portion that distends to accept the large prey, a typical muscular pyloric region and sphincter, and a short intestine less than 2 x the SVL of the larva. In many of its characteristics the larva of Lepidobatrachus resembles the adult.