Ameiva quadrilineata

Submitted by SpencerMurray 09 Feb
Scientific name:  Ameiva quadrilineata
Common names
Common names:  Four-lined Ameiva [en]
Overview: 

Ameiva quadrilineata, the Four-lined Ameiva, is a medium-sized ground-dwelling lizard native to Central America. Adults can reach snout-vent lengths of 88 mm (males) and 82 mm (females), and their long tails commonly exceed 160 mm, making up as much as 69% of the lizard’s total length. This species gets its name from the two pairs of yellow stripes running longitudinally along its brown back and dark flanks. Its belly is white, bluish, or copper-colored, its tail is blue, and its throat may be yellow or orange. Like other members of its genus, A. quadrilineata is a very active lizard, foraging for prey (mainly small arthropods) on and in the soil and leaf litter during the morning and early afternoon. This species reproduces year-round, although breeding activity may be concentrated around the beginning of the rainy season between April and June.

Associations
Associations: 

Ameiva quadrilineata preys on a variety of small arthropods, with a preference for spiders, grasshoppers, crickets, beetles, and larval ants (Hirth 1963, Savage 2002). A population of A. quadrilineata from the Caribbean beach of Tortuguero in the Limón Province of Costa Rica was also documented to prey heavily on the amphipods Talorchestia fritzi and T. marcuzzi (Hirth 1963). Hirth (1963) also observed one episode of cannibalism in this species, in which a large female ate a juvenile 45 mm in snout-vent length. Another individual was found to have eaten an egg of the sympatric lizard Basiliscus vittatus. Both of these unusual prey items, however, were consumed following several days of rain that likely limited foraging opportunities severely. The primary predators of the Tortuguero population of this species are the snakes Clelia clelia and Dryadophis melanolomus, although the ghost crab Ocypode quadratus may also prey on this species. Approximately 75% of this population was parasitized by the red mite Trombicula alfreddugesi (Hirth 1963).

Behaviour
Behaviour: 

Ameiva quadrilineata is a diurnal species that begins foraging for food in the early morning, and may continue into the afternoon on sunny days (Hirth 1963). This lizard is an active forager, and is commonly found digging or rummaging through sand, soil, or leaf litter in search of prey (Savage 2002). This species is heliophilic, regularly basking in sunlight and seeking shade to moderate its body temperature. When active, A. quadrilineata maintains its body temperature between 34.6 and 40.0 ˚C (Hirth 1963, Savage 2002), and while it can tolerate lower temperatures while inactive, prolonged exposure to temperatures above 40.0 ˚C appears to cause irreversible physiological damage (Hirth 1963). Home range size in A. quadrilineata is believed to be approximately 450 square meters for males and 190 square meters for females, with females showing tendencies to select a specific home site, such as a particular log, within their home range. This species appears not to be territorial, as there is little intraspecific aggression despite a high degree of overlap between multiple individuals’ home ranges (Hirth 1963).

Conservation status
Conservation Status: 

Although the effects on Ameiva quadrilineata of processes such as pollution or habitat destruction are not yet well understood, the IUCN Red List (2009) categorizes this species as Least Concern “because of its large distribution and tolerance of a variety of habitats, including altered environments” (Mayer and McCranie 2009).

Diagnostic description
Diagnostic Description: 

Ameiva quadrilineata is smaller than any other macroteiid lizard in Costa Rica (Savage 2002) and likely in its entire geographic range. It has two thin, light, and well-defined lateral and ventrolateral stripes on either side of its body, separated by dark lateral fields. Although this species has a light brown middorsal area with even margins, it never has a light vertebral stripe. The posterior gular scales of A. quadrilineata are substantially smaller than its anterior gular scales, and the border between the two is rather abrupt (Savage 2002).

Distribution
Distribution: 

Ameiva quadrilineata inhabits humid Central American lowlands, from southeastern Nicaragua through Costa Rica and into northwestern Panama. The mountains in central Costa Rica may constitute somewhat of a dispersal obstacle to this species (Hirth 1963, Savage 2002, Mayer and McCranie 2009).

Evolution
Evolution: 

In a phylogenetic study based on partial 12S and 16S mitochondrial rRNA sequences, Hower and Hedges (2003) found that three mainland South American species of Ameiva (A. ameiva, A. festiva, and A. undulata) were relatively basal members of their genus, and that the mainland lineage likely gave rise to new species as it colonized the West Indies from Central and South America. This trend would suggest that A. quadrilineata, another mainland species, may be relatively basal as well, but that hypothesis has not been tested, as A. quadrilineata was not included in this study (Hower and Hedges 2003). This species was originally described in by Hallowell in 1861 as Cnemidophorus quadrilineatus (Mayer and McCranie 2009).

Habitat
Habitat: 

Ameiva quadrilineata primarily inhabits humid Central American lowlands at altitudes from sea level to 1050 m asl, where it is found most commonly at forest edges and in disturbed habitats such as agricultural landscapes (Savage 2002, Mayer and McCranie 2009). This species is rarely if ever found in thick vegetation, but prefers more open, sunny areas such as the sunlit patches under trees, or beaches where available. It can frequently be found near houses (Hirth 1963).

Look alikes
Look alikes: 

Ecologically, Ameiva quadrilineata can be distinguished from its closest relatives because it “prefers much more open areas than Ameiva festiva or Ameiva leptophrys, is less shy and secretive than Ameiva undulata, and has longer diel activity periods than A. undulata” (Savage 2002). In terms of morphology, Ameiva quadrilineata can be distinguished from A. undulata by the absence of bars on its flanks, the presence of light longitudinal stripes, and a sudden, stark difference in the sizes of the anterior and posterior gular scales. It can be distinguished from A. leptophrys by the margins of the middorsal field, which are even rather than scalloped, and by the presence of fewer, larger parietal scales. The absence of a light vertebral stripe and the continuity of the lateral and ventrolateral stripes are sufficient to distinguish A. quadrilineata from A. festiva, and the enlarged collar scales and absence of light lateral spots separate A. quadrilineata from A. ameiva. Size may also be useful in distinguishing some of these species: A. quadrilineata reaches a maximum of 88 mm in snout-vent length (SVL), whereas A. undulata and A. ameiva may reach SVLs of 129 mm and 197 mm, respectively (Savage 2002).

Morphology
Morphology: 

Ameiva quadrilineata is a medium-sized lizard with a pointed snout and a long tail. The head is not distinct from the neck, except in large males which may have a jowl-like feature due to hypertrophied jaw muscles. The nostril is in the nasal suture and the head shields are smooth. The postnasals touch one prefrontal scale. There is just one frontal plate, usually three supraoculars, and an enlarged interparietal scale. The two large parietals are “in broad contact” (Savage 2002) with the interparietal and frontoparietal scales. The scales in the supraorbital semicircles do not reach the posterior margin of the frontal. As for gular scalation, the anterior gular scales are much larger than the posterior gular scales, from which they are suddenly differentiated. The enlarged collar scales occur in just one row on the posterior gular fold, and they are larger than the largest scales in the midgular patch. The scales near the center of the posterior surface of the forearm are somewhat enlarged and may be irregular or in a single row. The ventral scales occupy eight longitudinal rows. There are 18-42 femoral pores, and 25-34 lamellae under the fourth toe (Savage 2002).

The most striking aspect of the coloration of A. quadrilineata is a pair of bright, thin, and continuous longitudinal yellow stripes, running laterally and ventrolaterally on either side of the midline. In juveniles, the lateral fields are black, the middorsal field is light brown, and its margins are even. The venter may be copper to white in color, and the tail is blue. Females are similar to juveniles in coloration except that the middorsal field may have darker fleck marks and the throat is usually at least partially yellow. In adult males, the lateral fields are rust-colored rather than black, and the flanks are brown. The ventrolateral stripe may lose its continuity, and there is a dark ventrolateral field, the lower half of which is marked by a gray net-like pattern. The venter may be similar to that of females and juveniles or it may be blue. Reproductive males also have yellow to bright orange throats, although all stages may have dark spots on their throats. Adult males’ tails are brown, and all members of this species lack light spots on the upper surface of the thighs (Savage 2002).

Physical description
Size: 

Ameiva quadrilineata may reach up to 283 mm in total length, but the tail accounts for 67-69% of this length. In snout-vent length, males (66-88 mm) are slightly larger than females (62-82 mm) (Savage 2002).

Physiology
Physiology: 

Like many other lizards both inside and outside of the family Teiidae, Ameiva quadrilineata has a nasal salt gland from which it excretes excess sodium, potassium, and chloride. This may be especially important for osmotic regulation in beach populations that eat salty marine amphipods and have high exposures to salt water and salt spray (Hillman and Pough 1976).

Population structure
Population biology: 

Ameiva quadrilineata occurs at population densities between 32-64 individuals per hectare (Savage 2002). Population demographics in this species have not been studied in detail, but Hirth (1963) noted that predation made survival beyond the first year of life relatively rare, with few individuals reaching two years old.

Reproduction and life history
Life expectancy: 

The maximum life expectancy of Ameiva quadrilineata is approximately 2 years, but lifespans in the wild are much shorter, with only 10% of individuals reaching one year old (Hirth 1963). Savage (2002) notes that “individuals of this species rarely survive more than two breeding seasons” (Savage 2002).

Reproduction: 

Ameiva quadrilineata is oviparous, laying small clutches of one to three eggs (Smith 1968). Reproduction occurs year-round in this species, but it may peak at the beginning of the rainy season between April and June, resulting in maximum numbers of offspring in August and September (Hirth 1963, Savage 2002). Males reach sexual maturity at a smaller size than females, despite ultimately reaching larger body lengths. The sub-populations of this species most active in reproduction consist primarily of males above 66 mm in snout-vent length (SVL), and females above 62 mm in SVL; however, sexually mature males and females have been reported with SVLs as low as 58 mm and 48 mm, respectively (Hirth 1963, Smith 1968). While he did not definitively find any nests belonging to A quadrilineata, Hirth (1963) reports that the lizards in his Tortuguero population probably dig their nests in sandy soils in vegetated areas. Hirth (1963) also provides a detailed account of mating rituals in this species. Hatchling A. quadrilineata are approximately 30 mm in SVL and are believed to reach sexual maturity by the age of six months (Savage 2002). Smith (1968) provides a detailed account of reproductive physiology in this species.

Trends and threats
Threats: 

Some evidence suggests that Ameiva quadrilineata may be somewhat disturbance-tolerant, but the effects on this species of pollution and habitat destruction are not yet well understood (Mayer and McCranie 2009).

Trends: 

Population trends for Ameiva quadrilineata are unknown (Mayer and McCranie 2009).

Uses
Uses: 

Like many lizards, Ameiva quadrilineata may be sought after and raised in captivity by hobbyists and collectors.

References
References: 
Hillman, P.E. and Pough, F.H. 1976. Salt excretion in a beach lizard (Ameiva quadrilineata, Teiidae). Journal of Comparative Physiology B 109: 169-175.
Hirth, H.F. 1963. The ecology of two lizards on a tropical beach. Ecological Monographs 33(2): 83-112.
Hower, L.M. and Hedges, S.B. 2003. Molecular phylogeny and biogeography of West Indian teiid lizards of the genus Ameiva. Caribbean Journal of Science 39(3): 298-306.
Mayer, G.C. and McCranie, J.R. 2009. Ameiva quadrilineata. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. <www.iucnredlist.org). Downloaded on 18 January 2011.
Savage, J.M. 2002. The Amphibians and Reptiles of Costa Rica: A Herpetofauna between Two Continents, between Two Seas. Chicago, IL: University of Chicago Press. pp. 512-513.
Smith, R.E. 1968. Studies on reproduction in Costa Rican Ameiva festiva and Ameiva quadrilineata (Sauria: Teiidae). Copeia 1968(2): 236-239.
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Attribution
Rights holder:  Spencer Murray
Author(s):  Spencer Murray
Author(s):  Lee Dietterich
Editor(s):  Luke Mahler

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