Here at Anole Annals we like to obsess over our favorite lizards, anoles of course, but there are a vast array of other reptilian marvels out there, formidable Cyclurid iguanas, regally patterned Chilabothrus boas and of course the ever wary ground lizards of the Antilles (and elsewhere), the ameivas. Given the ample opportunity for exploration of these seemingly under appreciated animals I have taken my best shot at writing a post concerning ameivas, their morphology, ecology an various other bits and pieces of info I’ve picked up over the years; Enjoy!
The large neotropical genus Ameiva contains roughly thirty-two species largely distributed throughout eastern South America and the Caribbean with a few species extending into southern Central America. Within this genus are some of the most ubiquitous lizards of the neotropics, though due to their incredible swiftness and skittish demeanor it is rare that one ever sees one of these charismatic lizards out in the open for any extended period of time and even rarer that the casual observer may encounter enough of them within a single area to appreciate just how numerous they can be. This rather ambitious post focuses mainly on the biogeography of Ameiva, which in many ways mirrors that of Anolis. Most of the information presented herein comes from a 2012 paper which , among other things, revises the genus Ameiva, recognizing several monophyletic clades and excluding certain species once thought to belong to the genus. More info on ameivas, as well as some amazing pictures, can be found at Father Alejandro Sanchez’s website.
Four geographically coherent clades or species groups have been identified within Ameiva, two of which, the ameiva and bifrontata groups, occur in South and Central America as well as in Trinidad and Grenada, while the remaining two, the dorsalis and erythrocephala groups, are distributed parapatrically throughout the Caribbean. Two additional species, A. parecis and A. concolor remain unassigned to any of these four groups.
The bifrontata group is the smallest of the four clades, consisting of one polytypic species, A. bifrontata, as well as the closely related A. provitaae.
This group is almost entirely South American in distribution, occurring in Colombia and Venezuela as well as on the island of Aruba. The clade is thought to share common ancestry with the West Indian Ameiva species and both groups share several defining morphological characteristics the most obvious of which is the presence of mild to intense red coloration on the tip of the snout of most species, a feature shared by no other teiids.
The Caribbean Ameiva form a monophyletic clade thought to be of South American origin
with the South American A. bifrontata species group thought to be sister this one. The West Indian species can be further subdivided into the dorsalis and erythrocephala groups which have parapatric distributions across the Greater and Lesser Antilles respectively. Within the Greater Antillean islands, all species belong to the dorsalis group which extends from Cuba and the Bahamas to the Puerto Rican island bank. Within the the Greater Antilles, certain trends in body size and habitat use can be noticed across the islands. On Hispaniola and Puerto Rico, the ameivas can be divided into ecomorphs with each island being home to a “giant” species which is typically found preferentially in one type of habitat-be it xeric or mesic-but can be found in various other environments throughout its range , and a small, blue tailed, cryptically colored species which is typically restricted to hotter, more xeric conditions and is found in open, sunlit areas. In addition, on Hispaniola there exists one mid-sized species, A. taeniura, which is generalistic in habitat use while on small islands off Puerto Rico there exist three more species of varying size, which are all closely related to the Puerto Rican giant species A. exsul. So far phylogenetic studies of Ameiva have yielded conflicting results as to the relationships between like species on both islands with the small species A. lineolata of Hispaniola and A. wetmorei of Puerto Rico being inferred as sister species in the most recent phylogeny and A. wetmorei being inferred as the sister species of A. exsul in previous ones. The Hispaniolan giant form A. chrysolaema is closely related to A. exsul, though its large size is still likely to have been derived independently. It would be neat if the two forms really did exhibit convergent evolution like that found in Anolis.
Only one species of ameiva is present on each of the remaining Greater Antillean islands, Jamaica and Cuba. These are the Jamaican A. dorsalis and the Cuban A. auberi. These are both medium-sized species that prefer open areas but may be found across a more extensive range of habitats than the specialists found on Puerto Rico and Hispaniola.
In contrast to the convergence exhibited by the dwarf and giant forms of Puerto Rico and Hispaniola, the mid-sized forms of Jamaica, Cuba and Hispaniola are all closely related. On the Bahamas, two species of the dorsalis group occur; these are the aforementioned A. auberi and the small A. maynardi which greatly resembles its sister species A. lineolata of Hispaniola and lives in similar xeric, sunlit habitats on the Inagua islands.
The erythrocephala group inhabits the Lesser Antilles from Anguilla south to Dominica, though a now extinct species once existed on Martinique. This group consists of 10 mid-sized to large species, each endemic to a particular island or island bank where it is almost always the only native ameiva. This group is thought to be descended from the aforementioned dorsalis group, possibly from a Puerto Rican or Hispaniolan species. On small islands, melanistic species such as A. atrata and A. corax are found. Nearly all members of this clade, even melanistic forms, possess the characteristic pink snout mentioned earlier; in fact, only one of the three entirely black species, A. corvina, does not posses it. Though morphologically this group is not as variable as the dorsalis group, there is still considerable variation in size, with the largest species, A. fuscata, attaining a mean SVL of 200 mm, larger than some Greater Antillean giants, and the smallest species, A. griswoldi peaking at 124 mm. All species within the erythrocephala group are habitat generalists, though some species are either restricted to small xeric islands such as A. atrata of Redonda, or else are restricted to certain areas within their own island, such as A. pluvianotata of Montserrat.
Finally: The Ameiva Ameiva group consists of six large species inhabiting South and Central America as well as Isla de Providencia, Trinidad and Grenada in the Caribbean, where the only three insular species of this clade, A. fuliginosa, A. atrigularis and A. tobagana, are found. Both A. fuliginosa and A. tobagana are usually considered subspecies of the South American A. ameiva (top of page), though morphologically they are both quite distinct and appear to deserve full species status. Ameiva atrigularis, formerly considered a subspecies of A. ameiva, is found on Trinidad and Tobago as well as on mainland South America. This group possesses some variation in size, ranging from the moderately-sized A. a tobagana to A. praesignis, which is the largest ameiva species. Most species are quite similar ecologically.
The distribution of the genus Ameiva across the neotropics mirrors that of Anolis in that the species of the southern Lesser Antilles are immediately descended from South American forms (the roquet group of the Dactyloa clade of Anolis has a similar distribution to the A. ameiva group and also has its closest relatives in South America), while those from Dominica northwards to the Puerto Rican Island bank have their closest relatives on Puerto Rico and Hispaniola- much like the Lesser Antillean members of the Ctenonotus clade of Anolis. Interestingly the Dominican A. fuscata, which is the southernmost occurring member of the erythrocephala group and the closest geographically to the A. ameiva group, also shares certain characteristics of that group including large body size and pattern as well as several morphological attributes. The northernmost member of the Ameiva ameiva group is A. tobagana of Grenada, the Grenadines and St. Vincent. A. praesignis and A. ameiva of the A. ameiva group have also established populations in Florida
In addition to defining the relationships within Ameiva, the authors of the 2012 paper also revise the contents of the genus itself, excluding several South and Central American species formerly assigned to the undulata group of Ameiva and re-erecting the old generic name Holcosus to hold these species.
While not generally under threat, some species of Ameiva, such A. polops of St.Croix and A. griswoldi of Antigua, are in immediate danger of extinction in part or all of their ranges due to predation by exotic species-cats, dogs and most notably the mongoose, as well as by natural habitat destruction, such as in the case of A. pluvianotata of Montserrat which has decreased dramatically in population size due to the effects of volcanic activity on that island.
It would be a real shame to see any of these species go extinct like the ameivas of Martinique and Guadeloupe have; though anoles would almost certainly say otherwise as Ameivas are big predators of small lizards, including anoles which they can often be seen snatching from the trunks of trees with one quick motion.
That’s not to say that anoles are the only thing on their menu, they are active and opportunistic foragers and will gladly eat anything that can be made to fit in their mouths. During the daylight hours they are constantly on the hunt for food, they are in fact quite bold in this manner and will enter human settlements and even approach humans to beg for/steal whatever scraps can be found though they will quickly flee at the first hint of trouble- and good luck trying to catch them unless you have a lot of time on your hands and a don’t mind running around in circles all day, I sure haven’t had much success .
As an end note, ameivas, like some anoles, are shrouded in myth and superstition; for instance, even though I don’t know of ameivas as being vocal lizards, on Jamaica it is said that if you whack one with a stick or otherwise cross it, it will emit a loud squeak, summoning all its ameiva brethren who will then chase you relentlessly, though it has never been specified what happens if they manage to catch you. I have heard this same story from several people over the years, but I have seen many people try to kill these ameivas (Jamaicans have a peculiar hatred for reptiles) and so far any actual observation of this spectacle eludes me.
*Two new species of ameiva have recently been described. I am not sure which, if any, of the four species groups those species belong in.