BAJA CALIFORNIA LEGLESS LIZARD Anniella geronimensis – Shaw 1940

IDENTIFICATION: DISTRIBUTION: Anniella geronimensis occurs on the Pacific coast of the Baja California Peninsula from about 3.2 mi N of Colonia Guerrero south to the vicinity of Punta Baja, near El Rosario. It also occurs in the Pacific on Isla San Geronimo [...]]]>
Adult, 50′, Baja California, Mexico

Adults, 50′, Baja California, Mexico

BAJA CALIFORNIA LEGLESS LIZARD
Anniella geronimensis – Shaw 1940

IDENTIFICATION:
DISTRIBUTION:
Anniella geronimensis occurs on the Pacific coast of the Baja California Peninsula from about 3.2 mi N of Colonia Guerrero south to the vicinity of Punta Baja, near El Rosario. It also occurs in the Pacific on Isla San Geronimo and Isla San Martin.

HABITAT:
This species is found only in fine-grained dune sand within the immediate vicinity of the Pacific Ocean. It is found 4 km from the coast in a dune set within Arroyo Socorro, but is not known from any other inland locations. Within these dunes it is commonly found beneath the leaf-litter at the base of Brittlebush, Locoweed and Bursage; it may also be found beneath discarded trash such as cardboard.

Ocean Dune Habitat, Baja California, Mexico
NATURAL HISTORY:
Like A. pulchra, this lizard is viviparous and insectivorous. Unlike A. pulchra, it is found exclusively within fine-grained sandy swales and dunes within the immediate vicinity of the coast. Both species of Anniella occur together in the dunes near Colonia Guerrero, but geronimensis is far more abundant there. Gravid females have been found to contain only a single embryo; birthing is thought to occur in late summer and fall. Within the dune sets they inhabit, A. geronimensis appears to be more abundant on the windward side. Shaw (1953) reported on an individual he believed to be basking in the lower stems of a Brittlebush.
TAXONOMY:
Anniella belongs to the Family Anguidae.
TYPE:
Described as Anniella geronimensis by C. E. Shaw (1940). Holotype: SDSNH 7543. Type locality: Isla San Geronimo Island, Lower California [Baja California], Mexico.
PERSONAL NOTES:
I have found this species to be abundant and easy to unearth during the winter and spring; during summer it dives deeper in to the dune sand and is much harder to come across. In December, 2001 Chris Gruenwald, Gary Nafis and I unearthed 8 specimens in about 10 minutes at dusk at the above-pictured locality. We found several early the next morning to photograph. In June, 2002 Gary Nafis and I returned to this site and despite searching for an hour found no sign of Anniella.
CONSERVATION STATUS:
This species inhabits ecologically sensitive dune systems along a narrow coastal band that is quickly becoming populated by tourists and foriegn investors. Some residents have set up fences to keep ATV riders away from the dunes themselves, but this needs to become a more widespread practice before more habitat is destroyed. The dune sets inhabited by this species should be fully protected by Mexican law.
REFERENCES:
Shaw, C. E. 1940. A new species of legless lizard from San Geronimo Island, Lower California. Transactions of the San Diego Society of Natural History 9:225-228.
Shaw, C. E. 1953. Anniella pulchra and Anniella geronimensis, sympatric species. Herpetologica 8:167-170.

IDENTIFICATION: DISTRIBUTION: Anniella pulchra is found throughout northwestern Baja California from the US border south to at least Arroyo Pabellon, about 17 kms south of San Quintin (Hunt 1983). It occurs on both the desert (I. E. La Rumorosa) and pacific slopes of the Sierra Juarez, [...]]]> SILVERY LEGLESS LIZARD
Anniella pulchra – Gray 1852
Anniella pulchra pulchra – Gray 1852

IDENTIFICATION:
DISTRIBUTION:
Anniella pulchra is found throughout northwestern Baja California from the US border south to at least Arroyo Pabellon, about 17 kms south of San Quintin (Hunt 1983). It occurs on both the desert (I. E. La Rumorosa) and pacific slopes of the Sierra Juarez, but is not yet known from the desert slopes of the Sierra San Pedro Martir. It is found on the Pacific islands of Coronado (Norte and Sur), and Todos Santos (Sur). Elevational distribution from sea level to around 1,200 meters.

HABITAT:
Anniella pulchra is found in a wide variety of habitats, although sandy or loamy soil is always present. It may be found in beach dunes, coastal chaparral, inland chaparral, oak forest and high desert; it is likely that it is also found along arroyos much lower on the desert slope of the Sierra Juarez and Paso de San Matias than currently known. These lizards are usually found beneath surface objects such as trash, rocks and dead vegetation. They are also found crossing roads at night during periods of warm weather.

Coastal Dune habitat, Baja California, Mexico
NATURAL HISTORY:
Like A. geronimensis, this lizard is viviparous and insectivorous. Gravid females have been found to contain one or two embryos; birthing occurs in late summer and fall. Both species of Anniella occur together in the dunes near Colonia Guerrero, but geronimensis is far more abundant there.
TAXONOMY:
Anniella belongs to the Family Anguidae. The taxonomy of A. pulchra is under review; populations from Baja California and southern California are likely going to be described as a seperate species.
TYPE:
Described as Anniella pulchra by J. E. Gray (1852). Neotype: MVZ 64656. Type locality: 0.8 km southeast of Pinnacles National Monument, San Benito County, California.
PERSONAL NOTES:
I have seen this species in California, but never in Mexico. In California, I found the subspecies nigra to be common in the dunes of Monterrey Bay on rainy early spring days. I have never had luck finding Anniella in the dunes during warm weather; cold or rainy weather has always been my favorite “digging” weather. In 1996 I assisted in a pit-fall trap project near the Mexico border in San Diego County and we found two A. pulchra in the buckets one spring morning; this was quite unexpected as the soil on this chaparral hillside was quite hard-packed and seemed inhospitable to these lizards.
CONSERVATION STATUS:
The state of California considers this species to be one of Special Concern; in Baja California this species is quite common and widespread and is probably not in need of special protection.
REFERENCES:
Gray, J. E. 1852. Description of several new genera of reptiles, principally from the collection of the H. M. S. Herald. Ann. Mag. Nat. Hist. 10:437-440.
Hunt, L. E. 1983. A nomenclatural rearangement of the genus Anniella (Sauria: Anniellidae). Copeia 1983:79-89.
Shaw, C. E. 1953. Anniella pulchra and Anniella geronimensis, sympatric species. Herpetologica 8:167-170.