_Dorso granuloso, scabriusculo. Pedibus posticis subpalmatis. Corpore
membrisque nigris, abdomine maculâ magnâ transversâ ad partem
posteriorem et maculâ rotunda utrinque medium versus, palmis atque
plantis, omnibus coccineis._
_Phryniscus nigricans._ Weigm. Nov. Act. Leop. XVII. p. 264. Bibr. Hist.
Rept. VIII. p. 723.
_Chaunus formosus._ Tschudi Classif. Batrach.
Habitat, Maldonado and Bahia Blanca.
This curious little species has been described by Weigman under the
present name,—by Tschudi under the generic name of _Chaunus_, and fully
by Bibron, who retained the name originally given to it by Weigman. It
now remains only to correct, from Mr. Darwin’s notes, some points
respecting the colours, which had been mis-stated in consequence of the
action of the spirit in which the specimen had been preserved. The
colour of this curious miniature representation of a Toad, is “ink
black,” excepting the palms and soles of the feet, a large transverse
spot across the posterior part of the abdomen, two smaller ones near the
middle, and in some specimens a few scattered little spots, all of the
most intense vermilion red. There is one specimen from Bahia Blanca
which has also some small “buff-orange” spots on the upper part.[4] Mr.
Darwin observes that “the appearance of the vermilion colour is as if
the animal had crawled over a newly painted board;” and he adds—“This
Toad inhabits the most dry and sandy plains of Bahia Blanca, where there
is no appearance of water ever lodging.” The other specimens were taken
at Maldonado, where it inhabits the sand-dunes near the coast. Mr.
Darwin threw one into a pool of fresh-water, but he found it could
hardly swim, and he thinks, if unassisted, it would have been soon
drowned.
Footnote 4:
This specimen from Bahia Blanca has a much smoother skin than the
others; but from its similarity in all other characters there can be
no doubt of its specific identity with them.
This species is diurnal in its habits, and may be daily seen under a
scorching sun, crawling over the parched and loose sand. M. D’Orbigny
brought specimens from Monte Video.
DIMENSIONS.
Inches. Lines.
Length of the head and body 1 0
of the anterior extremities 0 5
of the posterior extremities 0 8
GENUS—UPERODON. _Bibr._
UPERODON ONATUM. _Mihi._