Alligator lizards, galliwasps, glass lizards, and relatives

(Anguidae)

Class Reptilia

Order Squamata

Suborder Sauria

Family Anguidae

Thumbnail description
Small to large lizards with elongated bodies; dorsal and ventral scales reinforced by underlying bone (osteoderms); and, in many species, reduced or absent limbs

Size
2.8–55.1 in (70–1,400 mm)

Number of genera, species
14 genera; 112 species

Habitat
Coastal dunes, desert, grasslands, chaparral, pine flatwoods, cloud forest, pine-oak forest, tropical wet forest, and paramo (high-altitude habitat that is cold, wet, and dominated by grasses and shrubs)

Conservation status
Extinct: 1 species; Critically Endangered: 3 species; Endangered: 1 species; Vulnerable: 1 species

Distribution
North, Central, and South America; the Greater and Lesser Antilles; Europe; North Africa; southwestern Asia; and Southeast Asia, including the islands of the Sunda Shelf

Evolution and systematics

The Anguidae is a monophyletic group within the Anguimorpha and is related most closely to either the Varanoidea (Varanidae, Lanthanotidae, and Helodermatidae) or the Xenosauridae and Shinisauridae. The 14 anguid genera are classified among four subfamilies as follows: Anguinae (glass lizards and slowworm—Ophisaurus and Anguis), Anniellinae (legless lizards—Anniella), Diploglossinae (galliwasps and allies—Celestus, Diploglossus, Ophiodes, Sauresia, and Wetmorena), and Gerrhonotinae (alligator lizards—Abronia, Barisia, Coloptychon, Elgaria, Gerrhonotus, and Mesaspis).

Phylogenetic analyses of DNA sequence data strongly support the monophyly of the Anguidae and three of its subfamilies, but monophyly of the Diploglossinae requires further evaluation. These analyses also suggest that the Gerrhonotinae and Anguinae are sister taxa and that the Anniellinae is the most basal subfamily. Within the Anguinae, Ophisaurus is paraphyletic with respect to Anguis; the geographically proximate A. fragilis and O. apodus are sister taxa. Within the Diploglossinae, Sauresia and Wetmorena appear to be sister taxa, and Ophiodes is related closely to the West Indian Diploglossus. Studies with a denser sampling of diploglossine taxa are needed to evaluate these findings further. Within the Gerrhonotinae, available data support a sister relationship between Elgaria and the other genera.

Fossils from the late Cretaceous (ca. 75–95 million years ago) of Europe have been assigned to a distinct subfamily (Glyptosaurinae) within the Anguidae. European fossils that may represent anguines or their close relatives are known from the Middle Eocene and later, and, according to J. A. Gauthier, fossils assigned to the Anguis-Ophisaurus apodus clade date back to the late Oligocene or early Miocene. On the other hand, Ophisaurus fossils are not known from North America before the late Miocene. The fossil record indicates that each anguid subfamily originated at least by the early Eocene (50–55 million years ago).

Physical characteristics

Anguids may be relatively small (e.g., Celestus macrotus and Elgaria parva) or extremely long (Anguis fragilis). Small bony elements called osteoderms are present beneath dorsal and ventral scales. A ventrolateral fold lined with tiny scales allows expansion of the armored skin when food, eggs, or developing young distend the body cavity. This fold is absent in the Anniellinae and most diploglossines. Limb reduction is common in this family, and some species lack limbs altogether. External ear openings are present in most species, but several species lack them. In diploglossines and gerrhonotines, the tail is usually shorter than the body, but in anguines the tail is much longer than the body. Anniellines

have a very short tail, typically less than two-thirds of the body length.

Caudal autotomy (self-amputation) is widespread among anguids, and fracture planes are present in some caudal vertebrae. Species of Abronia are specialized for an arboreal existence and have prehensile tails. Many anguids are some shade of bronze or brown (e.g., Ophisaurus attenuatus and Elgaria kingii), but some species exhibit more strking coloration (e.g., various shades of green in some Abronia and bright bands in some Diploglossus). Some species, such as Diploglossus fasciatus, may be boldly patterned. L. Vitt has suggested that D. lessonae juveniles mimic a toxic species of millipede with their bold markings.

Distribution

The Anniellinae, Diploglossinae, and Gerrhonotinae are restricted to the New World, but the Anguinae has representatives in North America, Europe, Asia, and North Africa. Phylogenetic analyses conducted by J. R. Macey and his colleagues suggest that anguids originated in the Northern Hemisphere (probably in North America) and only later colonized Africa and South America. Anguids are absent from sub-Saharan Africa, Madagascar, and Australia. Anguids occur from sea level to at least 12,470 ft (3,800 m).

Habitat

Anguids occur in a variety of habitats, from coastal dunes and desert scrub to grasslands above the tree line on tropical mountains. They inhabit a variety of forest types, from pineoak forest to lowland wet forest to cloud forest. While many anguid species are terrestrial, others are fossorial or arboreal.

Behavior

Most anguids easily autotomize (self-amputate) their tails when grasped, and the fragility of this appendage makes the name glass lizards (for Ophisaurus) particularly appropriate. Some anguids are active by day (e.g., Anguis fragilis), but others are nocturnal (e.g., some Diploglossus). Their slow movements and tendency to utilize leaf litter and other surface cover often render these lizards fairly inconspicuous.

Feeding ecology and diet

Anguids are carnivores that rely heavily on arthropod prey. These lizards typically move slowly and deliberately when foraging. In addition to arthropods, they take snails, slugs, nestling rodents, and other small vertebrates.

Reproductive biology

Both live birth and egg laying are widespread in this family. Anniellines give live birth to one to two young. Within the Anguinae, Anguis gives live birth, but all species of Ophisaurus lay eggs that are attended by the female. Both egg laying and live birth are found in the Diploglossinae and Gerrhonotinae.

Conservation status

The current IUCN listings underestimate the number of imperiled anguid species. The genus Abronia is in serious jeopardy from habitat destruction, as discussed thoughtfully by J. Campbell and D. Frost. Habitat destruction is also a grave problem for anguids in the West Indies.

Significance to humans

Anguids are in no way dangerous to humans and do not have commercial value outside the pet trade. As with all lizard groups, some anguids are erroneously believed to be venomous. Some people mistakenly think that the regenerated tail tip in Ophisaurus is a stinger.

Species accounts

List of Species

Moroccan glass lizard

Ophisaurus koellikeri

subfamily

Anguinae

taxonomy

Ophisaurus koellikeri Günther, 1873, North Africa, later restricted to Mogador, Morocco.

other common names

English: Koelliker's glass lizard; French: Ophisaure de Koelliker, l'orvet du Maroc; German: Marokko-schleiche, Türkispanzerschleiche; Spanish: Lagarto de cristal marroquí.

physical characteristics

This slender lizard with a long tail grows to 19.7 in (500 mm) in length. Forelimbs are absent; the greatly reduced hind limbs consist of small flaps near the cloaca. A ventrolateral fold is present, and the tail is extremely fragile. The dorsal coloration is brownish. Over the anterior two-thirds of the body, there are small dark spots (sometimes arranged in transverse rows). Most of the dark spots contain light, iridescent specks.

distribution

This is the only anguid species known from Africa; it is endemic to Morocco at elevations from 160 to 6,560+ ft (50–2,000+ m). Bons and Geniez suggested that it also may occur in Algeria.

habitat

The Moroccan glass lizard is known from regions with moderate to high amounts of rainfall; it inhabits open grassy areas near pine and oak forests and also agricultural areas.

behavior

This species spends much time hidden beneath stones or logs but frequently basks in the morning. Those that live at high elevations hibernate during the cold months. The Moroccan glass lizard rapidly flees from perceived predators and readily autotomizes the tail if it is captured.

feeding ecology and diet

This species actively forages for arthropods.

reproductive biology

Little is known of the reproductive biology of this species. Ovulation may occur in June, and it is possible that the female guards the eggs.

conservation status

Although this species has a limited distribution within Morocco, it is not known to be threatened.

significance to humans

None known.

California legless lizard

Anniella pulchra

subfamily

Anniellinae

taxonomy

Anniella pulchra Gray, 1852, 0.5 mi (0.8 km) southeast of Pinnacles National Monument, San Benito County, California, United States (as designated by Murphy and Smith, 1991). Two subspecies have been recognized.

other common names

Spanish: Culebra, Lagartija-sin patas californiana.

physical characteristics

The adult California legless lizard has a snout-vent length of 5.9–7.1 in (150–180 mm). This small, serpentiform lizard lacks external ear openings and limbs. The dorsal coloration is silvery gray, dark brown, or black. Three dark longitudinal stripes (one on the center of the back and one on each side of the body) are most distinct on gray individuals. The belly and sides of the body below the lateral stripes are yellow. The ventrolateral fold is absent, and the tail is short.

distribution

This species ranges from the San Francisco Bay Area of California south into northwestern Baja California; it also occurs on several offshore islands. It is known from sea level to 5,085 ft (1,550 m).

habitat

The species is found in areas with loose, moist soil (sand or loam) in chaparral, oak woodlands, and, in particular, coastal dunes with sparse vegetation.

behavior

The species is primarily fossorial by day but emerges to forage at night.

feeding ecology and diet

This species actively forages in leaf litter for small arthropods.

reproductive biology

From September to November, females typically give birth to one to two young.

conservation status

The species is not threatened at present, but agriculture has eliminated many California populations.

significance to humans

None known.

No common name

Celestus hylaius

subfamily

Diploglossinae

taxonomy

Celestus hylaius Savage and Lips, 1993, La Selva Biological Station, Canton de Sarapiqui, Heredia, Costa Rica, 130 ft (40 m) above sea level.

other common names

None known.

physical characteristics

This is a small lizard, with a total length up to 7.8 in (198 mm). It has short legs and a tail that contributes to slightly more than half of the total length. The dorsal ground color is bronze, with numerous black flecks. Ventrolaterally the black flecks form an irregular stripe. The belly is yellowish green.

distribution

This species is endemic to the lowlands of eastern Costa Rica.

habitat

The species has been collected from leaf litter in wet and moist forests.

behavior

Although little is known about this infrequently encountered species, it may be diurnal and terrestrial.

feeding ecology and diet

It probably actively forages for small arthropods, but the feeding ecology of this species has not been studied.

reproductive biology

The species probably bears live young.

conservation status

Not listed by the IUCN.

significance to humans

None known.

Coban alligator lizard

Abronia aurita

subfamily

Gerrhonotinae

taxonomy

Abronia aurita Cope, 1869, Vera Paz, Guatemala, near Peten and Cobán.

other common names

English: Golden arboreal alligator lizard; Spanish: Escorpión.

physical characteristics

This lizard is of moderate size, with snout-vent lengths of adults approximately 3.9–4.9 in (100–125 mm) and total lengths of adults approximately 9.8–12.2 in (250–310 mm). It has well-developed limbs and a prehensile tail. The head is broad posteriorly, narrowing toward the snout. Distinctive spinelike scales are present above the ear opening. The dorsal coloration is pale green or yellowish green with orange or yellow markings or both. The area around the eye is yellow.

distribution

The golden arboreal alligator lizard is endemic to the highlands of Guatemala. It is known from 6,560 to 8,730 ft (2,000–2,660 m) but may have occurred at lower elevations in the past.

habitat

The species inhabits pine-oak forest.

behavior

This species is diurnal and arboreal, often associated with large bromeliads or Spanish moss growing on oak trees. Males may behave aggressively toward each other.

feeding ecology and diet

This species readily takes arthropods in captivity, but little information is available about its feeding habits in the wild.

reproductive biology

A captive female gave birth to 12 young on January 26–28, 1992.

conservation status

The range of this species has been reduced drastically by habitat destruction.

significance to humans

Owing to its spectacular appearance and docile nature, this species is favored by herpetoculturists.

Texas alligator lizard

Gerrhonotus liocephalus

subfamily

Gerrhonotinae

taxonomy

Gerrhonotus liocephalus Wiegmann, 1828, Mexico, later restricted to Tlapancingo, Oaxaca. Up to six subspecies have been recognized.

other common names

Spanish: Culebra con patas, lagartija escorpión de Tejas.

physical characteristics

This large lizard grows to 19.7 in (500 mm) in length, though typically it is 9.8–15.7 in (250–400 mm) long. The Texas alligator lizard has strong jaws; four well-developed limbs; and a long, moderately prehensile tail. The dorsal ground color is reddish brown to dull yellow, with irregular transverse bands consisting of dark and light flecks.

distribution

This species occurs in central and southwestern Texas south to San Luis Potosí, Mexico.

habitat

It inhabits rocky hillsides with low vegetation.

behavior

The Texas alligator lizard is diurnal and primarily terrestrial. A slow-moving species, it may inflate itself with air when disturbed.

feeding ecology and diet

This species actively forages for arthropods and small rodents, snakes, and other lizards.

reproductive biology

Females attend their clutches of five to 31 eggs, which are laid once per year or more often.

conservation status

Not threatened.

significance to humans

None known.

Montane alligator lizard

Mesaspis monticola

subfamily

Gerrhonotinae

taxonomy

Mesaspis monticola Cope, 1878, summit of Pico Blanco, Costa Rica

other common names

Spanish: Dragón, lagartija de altura.

physical characteristics

These moderately sized lizards (9.3 in [236 mm] in total length) have four rather short limbs and a long tail. A ventrolateral fold is present. Males are bright green or yellowish green with extensive black flecking. Females and juveniles are brownish with black flecking.

distribution

The species occurs in the highlands of Costa Rica and western Panama from 5,900 to 12,470 ft (1,800 to 3,800 m).

habitat

The montane alligator lizard inhabits open areas within or at the edges of wet montane forests; it also is found in paramo.

behavior

The species is terrestrial and diurnal. It thermoregulates by basking on sunny mornings and may be forced to remain dormant on days without sunshine.

feeding ecology and diet

It actively forages for arthropods and juvenile salamanders.

reproductive biology

Females give live birth to two to 10 young and may stay with their offspring for a period after birth. It has been suggested that females reproduce only every other year.

conservation status

Not threatened.

significance to humans

In parts of its range people incorrectly consider this harmless lizard to be capable of delivering potent venom by stinging with its tail.

Resources

Books

Bons, Jacques, and Philippe Geniez. Amphibiens et Reptiles du Maroc. Barcelona: Asociación Herpetológica Española, 1996.

Grismer, L. Lee. Amphibians and Reptiles of Baja California, Including Its Pacific Islands and the Islands in the Sea of Cortés. Berkeley: University of California Press, 2002.

Savage, Jay M. The Amphibians and Reptiles of Costa Rica. Chicago: University of Chicago Press, 2002.

Schleich, H. Hermann, Werner Kästle, and Klaus Kabisch. Amphibians and Reptiles of North Africa. Koenigstein, Germany: Koeltz Scientific Publishers, 1996.

Periodicals

Campbell, Jonathan A., and José L. Camarillo. "A New Lizard of the Genus Diploglossus (Anguidae: Diploglossinae) from Mexico, with a Review of the Mexican and Northern Central American Species." Herpetologica 50 (1994): 193–209.

Campbell, Jonathan A., and Darrel R. Frost. "Anguid Lizards of the Genus Abronia: Revisionary Notes, Descriptions of Four New Species, a Phylogenetic Analysis, and Key." Bulletin of the American Museum of Natural History 216 (1993): 1–121.

Gauthier, Jacques A. "Fossil Xenosaurid and Anguid Lizards from the Early Eocene Wasatch Formation, Southeast Wyoming, and a Revision of the Anguioidea." Contributions to Geology (University of Wyoming) 21 (1982): 7–54.

Good, David A. "Phylogenetic Relationships Among Gerrhonotine Lizards." University of California Publications in Zoology 121 (1988): 1–138.

Macey, J. Robert, James A. Schulte II, Allan Larson, Boris S. Tuniyev, Nikolai Orlov, and Theodore J. Papenfuss. "Molecular Phylogenetics, tRNA Evolution, and Historical Biogeography in Anguid Lizards and Related Taxonomic Families." Molecular Phylogenetics and Evolution 12 (1999): 250–272.

Savage, Jay M., and Karen R. Lips. "A Review of the Status and Biogeography of the Lizard Genera Celestus and Diploglossus (Squamata: Anguidae), with Description of Two New Species from Costa Rica." Revista de Biologia Tropical 41, no. 3 (1993): 817–842.

Vitt, Laurie J. "Mimicry of Millipedes and Centipedes by Elongate Terrestrial Vertebrates." Research and Exploration 8 (1992): 76–95.

Ronald L. Gutberlet, Jr., PhD