The Amphibians and Reptiles of Sinaloa, Mexico - Smithsonian ...

AMPHIBIANS AND REPTILES OF SINALOA, MEXICO 99
a rock in an arroyo northeast of Concordia. The call was about two
seconds in duration and was issued every three or four minutes.
The following night a male and female were taken from a pool in the
arroyo. Two other males were collected as they called from beneath
a small log at the edge of a pond on July 7. A female taken at the
same time was gravid. Another series of males in chorus was
secured in August at Teacapan.
The call is a soft, high-pitched baaaaa. After some time it was
possible to distinguish between the call of G usta and that of G.
olivacea, which is lower in pitch and slightly louder. The characteristic
peep preceding the mazatlanensis call was not perceived from
usta and may be lacking.
The ranges of the two species of Gastrophryne overlap near
Mazatlan. The two species have not been taken sympatrically and
probably are ecologic replacements of each other in southern Sinaloa.
Gastrophryne usta has been collected in the same pond with Smilisca
baudinii, Phyllomedusa dacnicolor, Fternohyla fodiens, Hyla smithi,
Diaglena spatulata, Bufo mazatlanensis, and Hypopachus oxyrrhintts.
Distribution in Sinaloa.—Recorded from the coastal lowlands
from near Mazatlan southward. See Fig. 30.
Specimens examined.—i km. NE Concordia (°KU 73918-19); 4.5 mi. NE
Concordia (LACM 6464-65); 34 km. SE Escuimpa ("KU 73920-21);
Teacapan (LACM 6468-74); Venodio [Venadillo] ('USNM 73267); 16.3 mi.
SE Villa Uni6n (LACM 6467); 18 mi. SE Villa Union (LACM 6466).
Literature records.—Presidio (Parker, 1934:149); Venodio [VenadiHo]
(Kellogg, 1932:188; Smith and Taylor, 1948:94).
Hypopachus oxyrrhinus oxyrrhinus Boulenger
Hypopachus oxyrrhinus Boulenger, Ann. Mag. Nat. Hist., ser. 5, 11:344,
May, 1883 (type locality, Presidio de Mazatl&n, Sinaloa).
Hypopachus osxyrrhinus oxyrrhinus: Shannon and Humphrey, Herpetologtca,
14:89, July 23, 1958.
Remarks.—Sixteen specimens examined have dark brown pigment
on the side of the head from above the nostril and outer edge of the
eyelid, ventrally and posteriorly to the groin. The dark pigment
forms a sharp but irregular border dorsally, then fades gradually
into the pale ventral coloration. The dark pigment contains color
flecks that increase in size ventrally, becoming large round white
spots on the belly. These frogs resemble H. oxyrrhinus oois in this
aspect of their coloration, but none has an irregular dark line from
between the eyes to the groin (Taylor, 1940c=521, plate 62, figs. C
and D). Also, the Sinaloan frogs, which have snout-vent lengths of
36-49 (41) and foot lengths of 21-28 (24), are larger than H. o. ovis
as defined by Smith and Taylor (1948:95).