CERATOPHRYIDAE HORNED TOADS FAUNA PARAGUAY

CERATOPHRYIDAE - HORNED TOADS

Ceratophryids are stout frogs with huge heads, large gapes armed with vomerine teeth and short legs. They have protruding eyes and fat, rounded bodies when viewed dorsally, showing little differentiation of the head from the body. Though toad-like the Ceratophryids are actually frogs and the family was, until recently, treated as a subfamily of a larger Leptodactylidae. Ceratophryids are large, terrestrial and semi-aquatic frogs. Ceratophryids are aggressive and larger species are capable of giving a nasty bite. Adults are frequently cannibalistic.
They exhibit 8 free procoelous, holochordal presacral vertebrae. Ribs are absent. The urostyle is free with two condyles and the pectoral girdle arciferal. Sternum cartilaginous with a cartilaginous omosternum present. The clavicle does not overlie the scapular. Palatines are present. Teeth present on the maxilla and premaxilla, those on the former being long, pointed and non-pedicellate - Astralagus and calcaneum are fused only at the ends. No intercalary phalanges. The sartorius is a separate and distinct muscle. Eggs and larvae aquatic. 2n=26, some species are polyploid. Sperm with two unequal tail filaments.

Five species recorded in Paraguay classified into three different genera.

Ceratophrys and Chacophrys Horned Toads - Colourful and distinctive Ceratophryids with broadly-blotched patternation. High heads and large mouths earn them the nickname "Pacman Frogs". They lack an external vocal sac.

Lepidobatrachus Budgett´s Frogs - A group of three instantly-recognisable, but superficially similar large frogs with large heads, enormous gapes armed with fang-like teeth, and tiny eyes situated close together on the top of the head. They are rarely observed, spending much of the year underground and emerging only to breed. Specific identification is best achieved by studying the glandular ridges, pupil shape and the size and shape of the dorsal plate (if present). Members of this genus have been nicknamed "Freddy Krueger Frogs" because of their "ugly" appearance, aggressive defensive display and willingness to bite.

REFERENCES
Cei JM 1980 - Amphibians of Argentina - Monitore Zoologico Italiano Monografia 2.
Fouquette MJ (undated) - Synopsis of Recent Amphibians to Genus - Arizona University.

Key to Adults of Paraguayan Ceratophryidae

1a Over-sized head and enormous mouth. Tiny eyes situated close together on top of the head. Body bloated and depressed. Relatively uniform dorsal colouration with slight or no patternation ................. Lepidobatrachus 2
1b High head, with large, protruding eyes. Bold patternation on dorsal surface ................................................ 4

2a V-shaped paravertebral ridge conspicuous. Pupil round. Dorsal shield absent. ............... Lepidobatrachus laevis
2b V-shaped paravertebral ridge inconspicuous or fading out. Pupil rhomboid or vertical. Dorsal shield present. ............................................................................................................................................................................. 3

3a Pupil rhomboid when dilated, broadly vertical when contracted. No V-shaped glandular ridge. Dorsal shield small, much longer than it is wide. Dorsum grey or brown. ................................................ Lepidobatrachus asper
3b Pupil vertical when contracted, round with horizontal dorsal and ventral extension when dilated. V-shaped ridge poorly-developed. Dorsal shield large and rounded. Dorsum brown or red, with bright orange inguinal and axillary spots. ..................................................................................................................... Lepidobatrachus llanensis

4a Large (up to 125mm). Pupil with eye-bar and horns above eyes. Dorsolateral blotches present, so that when viewed dorsally a line of four large blotches is visible across back, arranged in two pairs either side of the midline. Pupil horizontal. Prominent "horns" over eyes. Elongated face and large mouth giving "Pacman" appearance ............................................................................................................................ Ceratophrys cranwelli.
4b Small (up to 55mm). Pupil without eye-bar and no horns above eyes. Dorsolateral blotches absent, so that when viewed dorsally only a single pair of medium-sized blotches is visible on the back, arranged in a pair either side of the midline. Pupil round. Eyes only slightly horned. Face not particularly elongated, appearing more "normal". . ................................................................................................................................ Chacophrys pierotti