Welcome to the first of what will be a series of primers on identifying Mexican Anolis lizards. When I was first becoming familiar with Mexican anoles, there were a few traits that stood out as being valuable for identification purposes. The goal is to make some posts outlining the traits and how to use them to identify anoles if you ever have the need. Let’s get started!
To begin, I want to stress how difficult it can be to identify many anole species in Mexico. The majority of species in the country are variable in dorsal patterning and roughly the same size (~40-60 mm SVL). On one of my early trips, I was shocked to find that four sympatric species in Guerrero had essentially identical size and dorsal patterns. Identifying them to species can be tricky if the individual in question is a female or juvenile, making it difficult to use dewlap coloration as the primary diagnostic trait for identification. Interestingly enough, one of the best ways to rule out species was to look at size and keeling of dorsal and ventral scales.
The first trait I will discuss is the presence of smooth ventral scales. This trait is quite effective at ruling out species in Mexico. Below I present some pictures of species that have smooth ventral scales so you can get a sense for what they look like (and apologies for the poor quality of some of the photographs). If you find a species with scales like this–congratulations! A fairly small subset of anoles in Mexico have smooth ventrals, with most occurring in Guerrero and Oaxaca. Members of four different species groups in Mexico tend to have smooth ventrals, detailed below.
Almost the entire Anolis gadovii group has smooth ventral scales that are often cycloid and overlapping (picture on the left below). This group has a fairly restricted distribution, only found in Michoacan, Guerrero, and Oaxaca. A few are spectacular (A. gadovii is among the coolest anoles in Mexico, pictured at the top of the post), but the rest are rather indistinct in coloration and therefore not very easy to identify without observing a male dewlap. Only one species in this group is known to regularly have weakly (but distinctly) keeled ventrals, and that species (A. macrinii) is easily identifiable due to being the only large, green anole in the Sierra Madre del Sur of Oaxaca.
Another group that commonly exhibits smooth ventral scales is the Anolis schiedii group, which is rather closely associated with either cloud forests or rainforests. Unlike the A. gadovii group, the A. schiedii group species are often recognizable and very similar to each other. Below are a couple example of typical schiedii group members (as well as a shot of the atypical “cave anole” on the right, A. alvarezdeltoroi) and two ventral shots that are fairly standard for the group. Individuals in the A. schiedii group can have weakly keeled ventrals that are more concentrated on the thoracic region and closer to the flanks, especially in females (Nieto-Montes de Oca 1994). If you look closely at the ventral shot below on the right, you will see light keeling on some scales. Some of these species, such as A. hobartsmithi and A. matudai, regularly have distinct keels on ventral scales. I’ll discuss that a little more in a later post, but know that the majority of species in Mexico have very obvious keeling on their ventrals, which is quite different from what you see here.
The third group in Mexico that has smooth ventral scales are members of the Anolis pentaprion group. This group is widespread throughout Central America, but only represented by two species in Mexico–A. beckeri and A. cristifer. Anolis beckeri is widespread in the Caribbean versant of southern Mexico, from at least Veracruz into Belize and Guatemala. Anolis cristifer is only known in Mexico from a portion of the Soconusco region of southern Chiapas, near Guatemala (where the bulk of its distribution lies). These species can be rather easily identified by their short limbs, short prehensile tails, and stocky bodies. Additionally, A. cristifer has bright blue eyes, which makes it stand out from other species you might confuse it with in extreme southern Chiapas. Both of these species are capable of very rapid color change.
And finally, there is Anolis rodriguezii. While another form in this group is described (A. microlepis, type locality: El Ocote, Chiapas), species boundaries are unclear and individuals throughout much of southern Mexico are regularly reported as A. rodriguezii. A proper taxonomic treatment of the group would be very welcome! These lizards are small, slender, and have granular scales on the dorsum in addition to their smooth, tiny ventral scales.
That is all for now! I will discuss keeled ventral scales in the next episode. Originally posted on the Biology of Mexican Herps blog. Check us out!
Reference
Nieto-Montes de Oca A (1994) A taxonomic review of the Anolis schiedii group (Squamata: Polychrotidae). Doctoral dissertation, University of Kansas, Systematics and Ecology.
- Dewlap Size and Seasonality in Mexican Anoles - May 18, 2020
- Mexican Anole Primer, Part 1: Smooth Ventral Scales - October 9, 2018
- Vanzolini’s Anole Video - April 20, 2017
Laura
They are very beautiful and so many varieties.
Thank you for your work and sharing your findings.
Levi Gray
Thank you for reading!
Peter Uez
Thanks for sorting this out, Levi. We really need a detailed comparative morphological analysis of anoles, not just DNA-based phylogenies 🙂
Levi Gray
I agree that there is a lot to explore still in morphology and anole relationships.
But morphology gets messy in anoles, and fast! To avoid misleading readers, for instance, I will have to review “tweeners” with respect to the traits I discuss and I’m still unsure as to whether I can effectively do it without making it confusing. If you look at enough specimens, there always appears to be some interesting variation even in many traits that initially appeared to be diagnostic. The existence of that variation makes many traits very difficult to incorporate into phylogenetic analyses.