The Puerto Rican Giant anole is, as the name suggests, native to Puerto Rico. These anoles typically have an SVL of 132 mm, and both sexes have large tail crests. While these bright green anoles can turn darken and turn brown, this species also has a rare brown morph! Juvenile cuvieri are grey-brown with striping and shift to their signature green when they mature.
Photo by Graham Reynolds
They eat insects, mainly beetles, moths and butterflies, and also occasionally fruit, snails, birds and of course, other anoles.
When I first encountered Anolis baleatus, this Hispaniolan crown-giant was mostly an inconvenience. At the time I was gathering data for my doctoral thesis by cycling preserved anoles through a µCT-scanner. Most of the adult specimens of A. baleatus were just too large to easily fit into the scan chamber, so it took a lot of patience and creativity to acquire any decent images of the appendicular girdles, which are the body parts I was interested in.
During that process I also acquired radiographic images of the head skeleton, and found unusual patterns of crenulation in this species. The cranium of Anolis baleatus displays a great degree of seemingly asymmetrical (or at least somewhat irregular) ornamentation across its dorsal surface. This is especially pronounced on the prefrontal and frontal bones, and completely obscures all superficial distinction between them in adult lizards. In adults, cranial ornamentation is also borne by the paired nasals, maxillae, and postorbitals, and the parietal (see figure).
Both Steven Poe (1998) and Susan
Evans (2008) mentioned this ossified garnish, but a thorough account of their
variation among anoles remains absent from the primary literature. Richard
Etheridge and Kevin de Queiroz (1988) were probably the first to report on skull
ornaments in anoles (as part of a discussion of several iguanian lizards with
similar cranial adornments), and remarked that the distribution patterns of
dermal rugae may reflect those of the topographically associated epidermal
scales.
Overall, this ornamentation appears
to be relatively uncommon among anoles, especially to the degree expressed in Anolis baleatus (and several other
crown-giant ecomorph anoles). Considering the osteologically robust appearance
of crown-giants, even at early stages of ontogenetic development, this gives
rise to questions regarding the development of these ornamental patterns.
Thanks to the collection efforts of Luke Mahler (University of Toronto), and a
postdoctoral position in his lab, I was able to acquire CT-image data
representing an ontogenetic series of this species, ranging from very young
juveniles to skeletally mature adults.
While parts of the paired frontals
of juveniles are covered in modest eminences, prominent cranial ornamentation
is absent from small specimens (see figure). Likely, growth of these ornaments
begins very late during ontogenetic development. Ornaments on the prefrontals
and parietal are only evident in specimens that, to the best of our judgement, are
approaching sexual maturity. We looked at fifteen specimens per sex,
representing a range of juvenile and subadult sizes, and this general pattern is
consistent throughout the image data. Schwartz (1974) inferred that anoles in
the ricordii group reach sexual
maturity between 100 and 110 mm snout-vent length (SVL), and we observed the
first prominent ornaments at sizes between 90 and 95 mm SVL. Assuming that
differences in size directly represent ontogenetic growth, these findings imply
that Anolisbaleatus starts to grow elaborate ornamentation as it approaches
sexual maturity, and that expansion and growth of these ornaments then
continues into skeletal maturity. Interestingly, both males and females appear
to develop them at roughly the same body size.
The function and evolutionary cause of these structures remain unknown, and these are questions we are currently investigating. Body size is an important correlate for the occurrence of cranial ornaments, but these structures may also conceivably play roles in defense, feeding, or intraspecific agonistic interactions. Stay tuned!
Videos
A. baleatus, female, 55 mm SVL
A. baleatus, female, 65 mm SVL
A. baleatus, female, 96 mm SVL
A. baleatus, female, 126 mm SVL
References
Etheridge, R. & de Queiroz, K. (1988): A phylogeny of Iguanidae.─ [In:] Estes, R.D. & Pregill, G.K. (eds.): Phylogenetic Relationships of the
Lizard Families: Essays Commemorating Charles L Camp, 283-367; Stanford:
Stanford University Press.
Evans, S. (2008): The skull of lizards and tuatara.─ [In:] Gans, C., Gaunt, A.S. &
Adler, K. (eds.), Biology of the Reptilia, vol. 20:1-347;
Society for the Study of Amphibians and Reptiles, Ithaca, New York.
Poe, S. (1998): Skull characters and the cladistic relationships of
the Hispaniolan dwarf twig Anolis.─ Herpetological Monographs, 12:192-236; The Herpetologists’ League.
Schwartz, A. (1974): An analysis of variation in the Hispaniolan
giant anole, Anolisricordi Dumeril and Bibron.─ Bull. Mus. Comp. Zool., 146:89-146.
Spring is the season for spotting crown-giant anoles in Miami!
I was hosting (recently graduated Lacertid-ophile, although closet anologist) Dr. Robert Heathcote for a few days this week, and after his failed attempt at catching a Cuban knight anole (A. equestris) a fortnight previous, I had promised to deliver him another! Now, I imagine many AA readers may chuckle at someone foolish enough to promise a crown-giant observation (myself included). Much to my relief luck was on our side and we managed to spot not one, but TWO species practically on top of each other!
A Cuban knight anole (A. equestris) and Jamaican giant anole (A. garmani) perched within 1-2m of each other in Miami FL – April 2nd 2014, JStroud
Cuban knight anoles (A. equestris) and Jamaican giant anoles (A. garmani) are both non-native introduced species to south Florida.
A. equestris (left) and A. garmani (right) – habitat overlap in Miami FL, JStroud
