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Report of molluscivory in Atractus carrioni Parker, 1930

Article

Report of molluscivory in Atractus carrioni Parker, 1930

Abstract

Information on the diet of Atractus carrioni and the first report of molluscivory for the genus are provided.
Report of molluscivory
in Atractus carrioni PARKER, 1930
Atractus carrioni PARKER, 1930 is a
neotropical snake endemic to the Loja
Valley, southern Andes of Ecuador (SAVAGE
1960). The genus Atractus comprises fos-
sorial and semifossorial snakes which pri-
marily prey upon earthworms, although
arthropod larvae, adult insects, acari, plant
matter and snake scales have also been
found in their digestive tracts (DUELLMAN
1978; HOOGMOED 1980; CUNHA & NASCI-
MENTO 1983; PEREZ-SANTOS & MORENO
1990; MARTINS & OLIVEIRA 1999; CISNEROS-
HEREDIA unpublished). Since our knowl-
edge on the ecology of most species of the
genus is very poor information on the diet of
A. carrioni and the first report of mollus-
civory for the genus are provided here.
Two adult male A. carrioni (deposited
at the Fundación Herpetógica G. Orcés,
FHGO) were collected 5 km east of the city
of Loja, Loja Province (ca. 79°09’W, 03°
59’S, 2300 m a.s.l.) on 01 May 1993 by J.-
M. TOUZET. Analysis of their digestive tracts
revealed the presence of terrestrial slugs
(Mollusca, Pulmonata). Specimen FHGO
652 (snout-vent length [SVL] = 315 mm,
tail length [TaL] = 45 mm) contained four
slugs in the stomach and one partially-
digested in the intestine, and specimen
FHGO 650 (SVL = 325 mm, TaL = 50 mm)
had two slugs in the stomach. The mean
length of all seven slugs was 7.8 mm (range
6.5-9.5 mm), mean width was 3.3 mm (2.5-
4.5 mm).
The genus Atractus is part of a clade
of small semifossorial xenodontine snakes
that feed on soft-bodied invertebrates (“goo-
eaters”). This clade is divided into a lum-
bricophagous subclade that includes
Atractus along with Adelphicos, Chapin-
ophis, Chersodromus, Geophis, Ninia, and
Omoadiphas; and a molluscivorous sub-
clade of Dipsas, Sibon, and Sibynomorphus
(CADLE & GREENE 1993; CAMPBELL &
SMITH 1998; FERNANDES 1995; KÖHLER et
al. 2001). Species of the molluscivorous
subclade have particular morphological
adaptations for eating snails and slugs
(PETERS 1960). Atractus carrioni does not
seem to have any adaptation for slug preda-
tion, and predation upon unshelled mollusks
is interpreted as opportunistic, and probably
occurs in other lumbricophagous species
especially when slugs are an abundant re-
source like in the habitat of A. carrioni. This
opportunistic pattern is also seen in mollus-
civorous species, e.g. a specimen of Dipsas
elegans BOULENGER, 1896 (oreas complex)
collected at the Cumbaya Valley (next to the
city of Quito, 2350 m a.s.l.) in 28 April 2004
regurgitated an earthworm 60 mm long.
ACKNOWLEDGMENTS: I am grateful to
Jean-Marc TOUZET (Fundación Herpetológica G.
Orcés) for the opportunity to study his specimens of
Atractus and to Carlos MONTUFAR (Universidad San
Francisco de Quito) for donating the specimen of
Dipsas elegans; to Daniel PROAÑO, Ma. Olga BORJA
and Pablo RIERA (Universidad San Francisco de Quito)
for laboratory assistance; to Jonathan CAMPBELL,
Walter SCHARGEL (The University of Texas at Arling-
ton), and Gunther KÖHLER (Forschungsinstitut und
Naturmuseum Senckenberg, Frankfurt a. M.) for shar-
ing literature. My gratitude to Maria Elena HEREDIA
and Laura HEREDIA for financial and moral support.
Universidad San Francisco de Quito provided institu-
tional support.
REFERENCES: CADLE, J. E. & GREENE, H. W.
(1993): Phylogenetic patterns, biogeography and the
ecological structure of Neotropical snake assemblages;
pp. 281-293. In: RICKLEFS, R. E. & SCHLUTER, D.:
Species diversity in ecological communities: historial
and geographical perspectives. Univ. Chicago Press,
Chicago. CAMPBELL, J. A. & SMITH, E. N. (1998): A
new genus and species of Colubrid snake from the
Sierra de las Minas of Guatemala.- Herpetologica,
Johnson City; 54(2): 207-220. CUNHA, O. R. DA &
NASCIMENTO, F. P. DO. (1983): Ofidios da Amazônia
XX.- As espécies de Atractus WAGLER, 1828, na Ama-
zônia Oriental e Maranhão. (Ophidia, Colubridae).-
Boletim do Museo Paraense Emílio Goeldi, Belem;
(123): 1-38. DUELLMAN, W. E. (1978): The biology of
an Equatorial herpetofauna in Amazonian Ecuador.-
Miscellaneous Publication, University of Kansas,
Museum of Natural History, Lawrence; (65): 1-352.
FERNANDES, R. (1995): Phylogeny of the dipsadine
snakes. Unpulb. PhD Diss, University of Texas at Ar-
lington; pp. 115. HOOGMOED, M. S. (1980): Revision
of the genus Atractus in Surinam, with the resurrection
of two species (Colubridae: Reptilia). Notes on the
Herpetofauna of Surinam VII.- Zoologische Verhande-
lingen, Leiden; (175): 1-47. KÖHLER, G. & WILSON, L.
D. & MCCRANIE, J. R. (2001): Anew genus and species
of colubrid snake from the Sierra de Omoa of north-
SHORT NOTE HERPETOZOA 18 (3/4) Wien, 30. Dezember 2005 SHORT NOTE 185
western Honduras.- Senckenbergiana biologica,
Frankfurt am Main; 81(1/2): 269-276. MARTINS, M. &
OLIVEIRA, E. (1999): Natural history of snakes in forests
of the Manaus Region, Central Amazonia, Brazil.-
Herpetological Natural History, Phoenix; 6 (2):78-150.
PEREZ-SANTOS, C. & MORENO, A. (1990): Anotaciones
biométricas y alimenticias de la serpiente neotropical
Atractus badius (BOIE, 1827) (Serpentes, Colubridae) de
la Colección del Museo Nacional de Ciencias Naturales
de Madrid.- Revista Española de Herpetología, Madrid;
4: 9-15. PETERS, J. A. (1960): The snakes of the sub-
family Dipsadinae.- Miscellaneous Publications,
Museum of Zoology, Univ. of Michigan, Ann Arbor;
(114): 1-224. SAVAGE, J. (1960): A revision of the
Ecuadorian snakes of the colubrid genus Atractus.-
Miscellaneous Publications, Museum of Zoology, Univ
of Michigan, Ann Arbor; (112): 1-86.
KEY WORDS: Reptilia, Squamata, Serpentes,
Colubridae, Atractus carrioni, diet, molluscivory,
Ecuador
SUBMITTED: February 02, 2005
AUTHOR: Diego F. CISNEROS-HEREDIA, Col-
lege of Biological and Environmental Sciences, Uni-
versidad San Francisco de Quito, Ave. Interoceánica
y calle Diego de Robles, Campus Cumbayá, Edif.
Maxwell. Casilla postal 17-12-841 Quito, Ecuador
< diegofrancisco_cisneros@yahoo. com >.
186 SHORT NOTE HERPETOZOA 18 (3/4) Wien, 30. Dezember 2005 SHORT NOTE
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Zoologisches Forschungsmuseum Alexander Koenig, sektion Herpetologie, Konrad Adenauer Alee 53 Bonn, germany. 3 División de Herpetología, cOrBiDi (centro de Ornitología y Biodiversidad) santa rita 105, of. 202, Huertos de san Antonio, surco, Lima, Peru. 4 current Address, Laboratório de Herpetologia, instituto Butantan, Avenida Vital Brazil, 1.500, Butantã, 05503‑900, são Paulo, sP, Brasil. 5 corresponding author: atractus@gmail.com. abstract. Atractus gigas was described based on a single specimen from western andes of ecuador. although recently, a second specimen of A. gigas was reported close to the type locality just on the basis of photographic vouchers. during the examination of ecuadorian and peruvian collections, we found additional specimens of this poorly known snake. We also collected new individuals of Atractus gigas during fieldwork carried out on northeastern portion of the peruvian andes. in this paper, we report new specimens, localities, and data on meristic, morphometric and color pattern variation for the species. We associate the variation displayed by these character systems with sexual, geographic, and ontogenetic phenomena respectively. We provide detailed comparisons and diagnosed Atractus gigas from all others members of this highly diverse and complex genus, and comment on their natural history and ontogeny.
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We present natural history information on 66 species of snakes found in the forests of the Manaus region, Central Amazonia, Brazil. For each species, we provide information on size, color pattern, habitat and microhabitat, feeding habits, reproduction, and defense. We also include a partial summary of the information available in the literature for Amazonian localities. Our results are based on nearly 800 captures or sightings of snakes made from 1990-95 at localities around Manaus, mostly at a primary forest reserve 25 km north of Manaus. Field data at this reserve were obtained during over 2600 person-h of visually searching for snakes, ca. 1600 of which occurred during time-constrained search. Temperature and relative humidity in Manaus are high and the amount of annual rainfall (2075 mm/yr) is relatively small, with a long dry season (4-7 mo). Of the 65 species for which information is available, 28 (42%) are primarily terrestrial, 20 (30%) fossorial and/or cryptozoic, 13 (20%) arboreal, and four (6%) aquatic, although many species use more than one microhabitat when active. Nearly all inactive snakes were found on vegetation. In relation to time of activity, 26 (41 %) of the 62 species for which information is available seem to be strictly diurnal, 13 (21%) strictly nocturnal, and 23 (38%) both diurnal and nocturnal. The five prey types most commonly consumed by snakes in the Manaus region are vertebrates: lizards (consumed by 58% of the species), frogs (39%), mammals (23%), birds (18%), and snakes (16%). A cluster analysis combining data on microhabitat use, diel activity, and diet resulted in several groups of species with similar habits. All these "guilds" included closely related species, as well as distantly related ones that converge in habits. These combined results indicate that in addition to current ecological factors (e.g., predation pressure, differential prey availability in different microhabitats), historical factors (phylogeny and biogeography) may have played an important role in determining the current natural history patterns of this snake assemblage. A high diversity of defensive tactics was found in this assemblage, and phylogeny may be a strong determinant factor for the occurrence of defensive tactics in each species. Contradicting generalizations on the timing and length of reproductive season in Amazonian snakes, juvenile recruitment seems to occur mainly during the rainy season in most species from the Manaus region, although some species seem to breed throughout the year. This may be a consequence of the prolonged dry season that occurs in the region, during which time some resources occur in limited supplies.
Casilla postal 17-12-841 Quito, Ecuador < diegofrancisco_cisneros@yahoo
  • Maxwell
Maxwell. Casilla postal 17-12-841 Quito, Ecuador < diegofrancisco_cisneros@yahoo. com >.
The snakes of the subfamily Dipsadinae
  • C Perez-Santos
  • A Moreno
  • J A Peters
  • J Savage
PEREZ-SANTOS, C. & MORENO, A. (1990): Anotaciones biométricas y alimenticias de la serpiente neotropical Atractus badius (BOIE, 1827) (Serpentes, Colubridae) de la Colección del Museo Nacional de Ciencias Naturales de Madrid.-Revista Española de Herpetología, Madrid; 4: 9-15. PETERS, J. A. (1960): The snakes of the subfamily Dipsadinae.-Miscellaneous Publications, Museum of Zoology, Univ. of Michigan, Ann Arbor; (114): 1-224. SAVAGE, J. (1960): A revision of the Ecuadorian snakes of the colubrid genus Atractus.-Miscellaneous Publications, Museum of Zoology, Univ of Michigan, Ann Arbor; (112): 1-86. KEY WORDS: Reptilia, Squamata, Serpentes, Colubridae, Atractus carrioni, diet, molluscivory, Ecuador SUBMITTED: February 02, 2005 AUTHOR: Diego F. CISNEROS-HEREDIA, College of Biological and Environmental Sciences, Universidad San Francisco de Quito, Ave. Interoceánica y calle Diego de Robles, Campus Cumbayá, Edif. Maxwell. Casilla postal 17-12-841 Quito, Ecuador < diegofrancisco_cisneros@yahoo. com >.