STEREOCYCLOPS INCRASSATUS (Brazilian Dumpy Frog).
DEFENSIVE BEHAVIOR. Stereocyclops incrassatus is a Brazilian microhylid, found in humid coastal forests in eastern Brazil
from Espírito Santo to Bahia (Frost 2009. Amphibian Species of
the World: an Online Reference. Version 5.3; http://research.amnh.
org/herpetology/amphibia/. American Museum of Natural History,
New York). Ecological or behavioral information for this genus is
scarce, but includes a description of feeding habits in S. incrassatus
(Teixeira et al. 2006. Bol. Mus. Biol. Mello Leitão 19:53–58) and
a description of defensive behavior in S. parkeri (Sazima 1978.
Biotropica 10:158). Herein, we describe an unreported defensive
behavior for S. incrassatus.
At ca. 1700 h on 12 March 2009, we observed the defensive
behavior of an adult male S. incrassatus (44 mm SVL) against
a predation attempt by an adult colubrid snake, Liophis milliaris
merremi (559 mm SVL. 127 mm TL). The animals were found
in the vicinity of the municipality of Itacaré, Bahia state, Brazil
(WGS84, 14.2888128°S, 38.984219°W; elev. ca. 10 m). The snake
was trying to swallow the frog headfirst. With the head already
inside of snake’s mouth, the frog was displaying the following
defensive position: the head was pressed against the ground, the
back was raised, the body inflated, and the fore and hind limbs
were strongly retracted against the body, giving the frog a solid
and round shape. When we approached, the snake regurgitated the
frog and we noticed that its mouth and a small part of the frog’s
body was covered by a glue-like secretion produced by the frog.
The secretion was visibly sticky, as it adhered sand grains to both
animals. It was not apparently whitish, but the adhered sand might
influence our perception of the color of the secretion. The secretion
made it difficult for the snake to open its mouth for approximately
a minute. After several unsuccessful attempts, the snake was finally
able to open its mouth by itself. During that time, the frog remained
in the position described above until, in the hands of one of us, it
flattened its body and stretched out its four limbs. When placed on
the ground it raised its head and remained in this flattened position
for more than a minute (Fig. 1).
This is the first description of defensive behavior for S. incrassatus. This is the first time that a defensive posture with all the
limbs pressed against the body and the head pressed against the
FIG. 1. Posture maintained by a Stereocyclops incrassatus after being
handled by one of the observers.
210
ground has been reported for a Brazilian microhylid. Flattening
the body and stretching all the limbs at the same time has also not
been previously described for any Brazilian microhylid. We did
not see any color in the S. incrassatus secretion. Secretion of sticky
substances is a useful defensive tactic, as it causes almost immediate liberation of the prey (Evans and Brodie. 1994. J. Herpetol.
28:499–502). All these data support the idea that many anurans
may combine secretions with different body positions to increase
defense success.
The specimens are deposited in the herpetological collection of
the Museu de Zoologia da Universidade de São Paulo (MZUSP),
São Paulo, Brazil (Liophis miliaris merremi, MZUSP 17732, and
S. incrassatus, MZUSP 141343). We thank IBAMA for collection
permits (14555-1).
Submitted by AGUSTÍN CAMACHO GUERRERO (e-mail:
[email protected]), RENATA CECÍLIA AMARO
(e-mail: [email protected]), and MIGUEL TREFAUT RODRIGUES (e-mail: [email protected]), Departamento de Zoologia,
Instituto de Biociências, Universidade de São Paulo, Caixa Postal
11.461, CEP 05422–970, São Paulo, SP, Brazil.
CROCODYLIA — CROCODILIANS
CROCODYLUS ACUTUS (American Crocodile). NESTING
ECOLOGY. Crocodylus acutus is widely distributed in the Atlantic and Pacific coasts of Mexico, Central America, and northern
South America, many Caribbean islands, and southern Florida
(Ernst et al. 1999. Cat. Amer. Amph. Rept. 700:1–17). Information on nesting ecology has been documented in Caribbean atolls
and coast habitat (Ogden 1978. J. Herpetol. 12:183–196; Platt
and Thorbjarnarson 2000. Copeia 2000:869–873; Casas-Andreu
2003. Acta Zool. Mex. [n.s.] 89:111–128; Mazzotti et al. 2007.
Herpetol. Rev. 38:285–289; Charruau et al. 2010. J. Nat. Hist.,
in press). However, there is a paucity of information on nesting
ecology of C. acutus in mainland and man-made habitat. Hence,
here we present observations on its nesting ecology in El Cajon
Reservoir in central Honduras.
We searched for nests around the main rivers and secondary
tributaries of El Cajon Reservoir (15.01078ºN, 87.71149ºW, datum:
WGS84, elev. 285 m) in February–April 2005. We found 30 nests
of C. acutus: two on the Yure River, 16 on the Humuya River, and
12 on the Sulaco River. Nest holes were constructed by C. acutus
that were found in the shoreline vegetation and elevated areas away
from shoreline and creeks. The nest areas were characterized by
very steep slopes and the presence of sandy and rocky soil.
We observed hatchlings at each nest site during May and June.
The number of hatchlings varied from 10 to 21 per nest on the
Yure River, 10 to 27 on the Humuya River, and 10 to 33 on the
Sulaco River. Successful nests were determined by the presence
of eggshell membranes indicating the nests were excavated by the
nesting female. Platt and Thorbjarnarson (2000, op. cit.) observed
that females defend nests from predators but parental care was
minimal or non-active. In El Cajon Reservoir, we observed active
parental care during our surveys.
We thank Programa Multifase de Manejo de Recursos Naturales en Cuencas Prioritarias-MARENA who provided financial
and equipment support. We wish to acknowledge Roney Buezo,
manager of Grupo Facilitador Humuya Medio, and José Francisco
Herpetological Review 41(2), 2010