ANIMAS RIDGE-NOSED RATTLESNAKE Crotalus willardi – Meek 1905 Crotalus willardi obscurus – Harris 1974

IDENTIFICATION:

DISTRIBUTION: In Mexico, this rattlesnake is found only in the Sierra San Luis of Sonora and Chihuahua; it also occurs in the United States in the Animas and Peloncillo Mountains.

HABITAT: Madrean [...]]]>
Adult, 6,000′, Hidalgo County, New Mexico

Adult, 6,000′, Hidalgo County, New Mexico

Close-Up of Head

Close-Up of Head

ANIMAS RIDGE-NOSED RATTLESNAKE
Crotalus willardi – Meek 1905
Crotalus willardi obscurus – Harris 1974

IDENTIFICATION:

DISTRIBUTION:
In Mexico, this rattlesnake is found only in the Sierra San Luis of Sonora and Chihuahua; it also occurs in the United States in the Animas and Peloncillo Mountains.

HABITAT:

Madrean Woodland Habitat, 6,000′, Hidalgo County, New Mexico

NATURAL HISTORY:

TAXONOMY:

TYPE:

PERSONAL NOTES:
I am extremely fortunate to have seen this snake once, in the Peloncillo Mountains of Hidalgo County, New Mexico. In August, 2005 two friends and I made a spur of the moment trip to this range on the slight chance we would see an obscurus, and obviously it worked out well for us! It took us a mere 45 minutes of poking around to locate this beautiful adult snake. Other species found the same day in this area were Sceloporus virgatus, Urosaurus ornatus, Trimorphodon biscutatus lambda, and Crotalus molossus molossus.

CONSERVATION STATUS:
In the United States, this snake is strictly protected on a federal level. Populations in both the United States and Mexico are stable, and it appears that there is no immediate concern as to the existance of this snake in the wild. It’s limited geographic distribution and supposed threat of rampant collection are the reasons for obscurus to be protected in the U.S.

REFERENCES:
Campbell, J. A. and W. W. Lamar. 2004. The Venomous Reptiles of the Western Hemisphere. Cornell Univ. Press, Ithaca, New York, 870 pp.

CORAL EARTH SNAKE Geophis semidoliatus – Dumeril, Bibron & Dumeril 1854

IDENTIFICATION:

DISTRIBUTION:

HABITAT: Banana Grove Habitat, 200′, Veracruz, Mexico

NATURAL HISTORY:

TAXONOMY:

TYPE:

PERSONAL NOTES:

REFERENCES:

MORELET’S LEAF FROG Agalychnis moreletii – Dumeril 1853

IDENTIFICATION: DISTRIBUTION: Historically, Agalychnis moreletii is found in several widely-disjunct regions of southern Mexico; In Puebla it is known from the Sierra Norte, in Veracruz from Cuautlapan and the Los Tuxtlas region, in Oaxaca from the Sierra Juarez [...]]]>
Adult Male, 4,500′, Oaxaca, Mexico

Adult Male, 4,500′, Oaxaca, Mexico

Inactive Adult Male, 4,500′, Oaxaca, Mexico

MORELET’S LEAF FROG
Agalychnis moreletii – Dumeril 1853

IDENTIFICATION:
DISTRIBUTION:
Historically, Agalychnis moreletii is found in several widely-disjunct regions of southern Mexico; In Puebla it is known from the Sierra Norte, in Veracruz from Cuautlapan and the Los Tuxtlas region, in Oaxaca from the Sierra Juarez and Sierra Miahuatlan, from Chiapas in the Sierra Madre de Chiapas and Tapilula/Pueblo Nuevo Solistahuacan, and in the Sierra Madre del Sur of Guerrero. Elevational distribution from 300-1500 m.

HABITAT:

Tropical Montane Habitat, 4,500′, Oaxaca, Mexico

Man-Made Oviposition Site, 4,500′, Oaxaca, Mexico

NATURAL HISTORY:
TAXONOMY:
TYPE:
Described as Hyla moreletii by Dumeril (1853). Syntypes: MNHNP 428. Type locality: “Vera-Paz”, Guatemala; corrected to “Coban in [Departamento Alta] Vera Paz, Guatemala” by Kellogg (1932).
PERSONAL NOTES:
On the night of July 8, 2005 I had the good fortune to discover this species calling from around an old well near Vista Hermosa, Sierra Juarez, Oaxaca. Three males were giving half-hearted vocalizations while perched on cattails about 3-4′ above the water. One Smilisca cyanosticta was also calling from a floating position in the well. On a forested slope nearby, what I believe to be Anotheca spinosa called sporadically. There was no rain on this evening.
Also of note was the fact that the well was full of nearly transformed, as well as 50% grown Agalychnis tadpoles. This indicates that A. moreleti has a lengthy breeding season.
In July, 2006 I returned to Vista Hermosa with Jesse Delia to survey for montane stream-breeders. We camped at the Agalychnis moreleti breeding site and found many adult animals around the well. Also seen were several egg masses attached to cattails above the waters edge as well as tadpoles of all stages of development.
CONSERVATION STATUS:
IUCN Red List status for this species is “Critically Endangered” due to a projected population decline of 80% over the next ten years due to habitat loss and infection with the Chytrid fungus; surveyors in the states of Guerrero, Oaxaca and Chiapas, Mexico reported this species extirpated from all sites they visited. (In July, 2005 I found an extant breeding population in the Sierra Juarez of Oaxaca – photographed above).
REFERENCES:
Faivovich, J., C. F. B. Haddad, P. C. A. Garcia, D. R. Frost, J. A. Campbell, and W. C. Wheeler. 2005. Systematic review of the frog family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision. Bulletin of the American Museum of Natural History 294:1-240.
Lips, K. R., J. R. Mendelson 3rd, A. Munoz-Alonso, L. Canseco-Marquez and D. G. Mulcahy. 2004. Amphibian population declines in montane southern Mexico: resurveys of historical localities. Biological Conservation 119(2004):555-564.

MARINE TOAD Rhinella marina – Linnaeus 1758

IDENTIFICATION: DISTRIBUTION: HABITAT: Tropical Lowland Habitat, 300′, Tamaulipas, Mexico Rain Forest Habitat, 750′, Sierra de los Tuxtlas, Veracruz, Mexico Habitat, 500′, Oaxaca, Mexico Pacific Lowland Habitat, 100′, Guerrero, Mexico Temporary Pond Oviposition Site, 500′, Oaxaca, Mexico

NATURAL HISTORY: TAXONOMY: TYPE: PERSONAL NOTES: CONSERVATION STATUS: REFERENCES:

MEXICO BURROWING TOAD Rhinophrynus dorsalis – Dumeril & Bibron 1841

IDENTIFICATION: DISTRIBUTION: R. dorsalis is found from the United States to Costa Rica. [...]]]>
Adult Male, Atlantic Versant Color Variant, 500′, Oaxaca, Mexico

Adult Male, Pacific Versant Color Variant, 100′, Oaxaca, Mexico

Adult Male, Pacific Versant Aberrant, 100′, Oaxaca, Mexico

Adults in Amplexus, 200′, Oaxaca, Mexico

Close-Up of Hind Foot Spade, an Effective Burrowing Tool

MEXICO BURROWING TOAD
Rhinophrynus dorsalis – Dumeril & Bibron 1841

IDENTIFICATION:
DISTRIBUTION:
R. dorsalis is found from the United States to Costa Rica. In Mexico it occurs on both coasts: on the Pacific from the mouth of the Rio Balsas in Guerrero to the Guatemala border in Chiapas; on the Atlantic from the Rio Grande (Texas border) south along the gulf lowlands through the Yucatan Peninsula to Guatemala and Belize. Elevational distribution from sea level to 500 m.

HABITAT:

Temporary Pond Oviposition Site, 500′, Oaxaca, Mexico

Pacific Lowland Habitat, 100′, Guerrero, Mexico

NATURAL HISTORY:
TAXONOMY:
The sole member of the family Rhinophrynidae. Populations of this frog on the Atlantic and Pacific versants of Mexico display distinct differences in color – Pacific animals being yellow and black, while Atlantic animals are orange/red and black. Further investigation in geographic variation within R. dorsalis may reveal the presence of unnamed species.
TYPE:
Described as Rhinophrynus dorsalis by Dumeril and Bibron (1841). Holotype: MNHNP 693. Type locality: “Vera-Cruz”, Mexico.
PERSONAL NOTES:
In July, 2005 I had the good fortune in finding my first breeding choruses of R. dorsalis in the Atlantic foothills of Oaxaca, Mexico. The combined calls coming from a roadside pond was absolutely eerie, and unnerved my hunting partner a bit. The frogs called from floating positions along waters’ edge, usually from within mats of floating grass cuttings. Other species calling from this pond were Trachycephalus venulosus, Scinax staufferi, Smilisca baudinii, and Leptodactylus melanonotus.
A few nights later, on the coast of Oaxaca (Hwy 200) we were lucky enough to witness a mass breeding migration of Rhinophrynus. Intense thunderstorm activity had ocurred earlier in the evening, and the road was swarming with R. dorsalis, Triprion, Incilius, and several other species of amphibians. Every roadside ditch from Salina Cruz to Huatulco seemed to have R. dorsalis calling from it’s muddy water, and in some places the road was covered with so many individuals that it was impossible to miss them all. Many Rhinophrynus were crossing the road while in amplexus (see photo above). Thankfully traffic was light on this evening, reducing the number of amphibians killed on the highway.
CONSERVATION STATUS:
IUCN Red List status is currently that of “Least Concern” due to this species’ wide geographic distribution, tolerance of a wide variety of habitats (including those modified by humans) and a presumed large, stable worldwide population.
REFERENCES:

MEXICO BEADED LIZARD Heloderma horridum – Wiegmann 1829 Heloderma horridum horridum – Wiegmann 1829

IDENTIFICATION: DISTRIBUTION: HABITAT: Habitat, 250′, Sinaloa, Mexico Habitat, 500′, Oaxaca, Mexico

NATURAL HISTORY: TAXONOMY: TYPE: PERSONAL NOTES: CONSERVATION STATUS: REFERENCES:

ISLA SANTA CATALINA IGUANA Dipsosaurus catalinensis – Van Denburgh 1922

IDENTIFICATION: DISTRIBUTION: HABITAT: NATURAL HISTORY: TAXONOMY: TYPE: PERSONAL NOTES: CONSERVATION STATUS: REFERENCES:

IDENTIFICATION:

DISTRIBUTION:

HABITAT:

NATURAL HISTORY:

TAXONOMY:

TYPE:

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CONSERVATION STATUS:

REFERENCES:

AMERICAN CROCODILE Crocodylus acutus – Cuvier 1807

IDENTIFICATION: DISTRIBUTION: HABITAT: Habitat, 50′, Nayarit, Mexico

NATURAL HISTORY: TAXONOMY: TYPE: PERSONAL NOTES: CONSERVATION STATUS: REFERENCES: