Though anoles are way more nicely studied and understood within the Caribbean and United States, there’s a first rate quantity of variety of those lizards all through South America as nicely. In session with Jonathan Losos, I’ve agreed to write down a sequence of posts outlining the South American variety (elements 1 and a pair of), invasives (half 3), and conservation (half 4) of those animals. This publish (variety half 1) will describe the species that happen within the areas of South America north and west of the Andes alongside the Caribbean and Pacific Coasts, respectively, whereas variety half 2 will concentrate on the Amazon and the whole lot south and east of the Amazon.
In case you don’t know me, I had expertise as a graduate scholar learning lizard purposeful morphology of toes and tails in North, Central, and South America. Extra lately, I’ve grow to be means too concerned in figuring out lizards on iNaturalist.org, with a concentrate on lizards of the New World. To fulfill my very own explicit obsessiveness, I’ve tried to establish each lizard noticed within the Amazon (all 300+ species of them!) and have expanded these lizard-identifying efforts into different areas as nicely. It was these efforts that gave me the concept that maybe the AnoleAnnals is likely to be fascinated with what I’ve seen from this comparatively understudied a part of the world. As such, I’ll draw liberally from knowledge obtainable on iNaturalist for instance my factors.
Anole variety alongside Caribbean and Pacific Coasts
As of this writing, there are at the moment practically 12,000 observations on iNaturalist of 102 species Anolis in South America (“analysis grade” observations filtered by “wild” and “has photographs”). Evaluate this to the 238,000 observations of 270 species from North America (on iNat this area consists of all of Central America, Mexico, america, and the Caribbean). Solely eight of the species of South American anoles are launched non-native species (extra on this partially 3). This means that there are practically 100 species of Anolis endemic to South America. Clearly, the anoles from South America are usually not as numerous and never as nicely noticed as these from different areas.
Anoles alongside the Pacific Coast vary from southern Ecuador (and maybe northern Peru, however not nicely documented) north to the junction with Central America and proceed alongside the Caribbean Coast east to the mouth of the Orinoco River in Venezuela (be aware: in keeping with iNaturalist, Guyana, Suriname, and French Guiana are a part of the Amazon area despite the fact that they is probably not a part of the Amazon watershed). This area is separated from the Amazon by the Andes Mountains and Orinoco River and only a few species cross these explicit limitations. Therefore, lots of the anoles of northern South America nonetheless have some extent of endemism and it’s this endemism (and the ensuing beta variety) that I spotlight beneath. Remember the fact that new species are being described regularly, so the checklist beneath is nearly actually incomplete, however nonetheless illustrates my common level.
The species of Anolis that happen in north and west of the Andes embrace (organized by their geographic distribution):
Western (non-Amazonian) Ecuador (n=9)
A. bionotatus, A. bitectus, A. fasciatus, A. festae, A. lyra, A. neomonteae, A. parilis, A. peraccae, A. proboscis
Western (non-Amazonian) Colombia (n=18)
A. anchicayae, A. antioquiae, A. antonii, A. calimae, A. danieli, A. eulaemus, A. gorgonae, A. heterodermus, A. maculigula, A. macrolepis, A. mariarum, A. medemi, A. quimbaya, A. solitarius, A. sulcifrons, A. tolimensis, A. urraoi, A. ventrimaculatus
Western Ecuador/Colombia (n=13)
A. aequatorialis, A. anchicayae, A. chloris, A. dracula, A. fraseri, A. gemmosus, A. gracilipes, A. granuliceps, A. limon, A. lynchi, A. maculiventris, A. parvauritus, A. princeps
Northern Colombia/Venezuela (n=3)
A. jacare, A. onca, A. tetarii
Northern Venezuela (n=4)
A. anatoloros, A. annectans, A. squamulatus, A. tigrinus
Aruba, Bonaire, and/or Curaçao (A-B-C islands) (n=2)
A. bonairensis, A. lineatus
Present in western Colombia in addition to crossing the Darién Hole into Central America (n=8)
A. biporcatus, A. gaigei, A. latifrons, A. poecilopus, A. purpurescens, A. triumphalis, A. tropidogaster, A. vittigerus
Alongside Caribbean Coast in addition to crossing into the Amazon (n=2)
A. auratus, A. planiceps
Non-native anoles (n=8)
A. aeneus, A. cristatellus, A. marmoratus, A. porcatus, A. richardii, A. sagrei, A. trinitatis, A. wattsii
A number of issues grow to be obvious when contemplating the above variety.
—First, there are roughly 67 species of anoles that happen north of the Amazon. On condition that there are solely about 102 anole species that happen in all of South America, maybe 2/3 happen within the space adjoining to the speciose Caribbean. That leaves only one/3 of the South American anole species occurring south and east of the Andes Mountains.
—Second, of the 67 anole species discovered north of the Amazon, 47 species (70%) are endemic to this area of mainland South America, two species (3%) are endemic to the A-B-C islands, eight species (12%) cross from mainland South America into Central America, and two species (3%) are discovered extensively within the Amazon as nicely. So, not as numerous as North America, however with excellent regional endemism. This regional endemism interprets into a formidable beta variety with geographic alternative in all probability the rule reasonably than the exception. In different phrases, when travelling from one valley to the subsequent, species alternative (beta variety) happens at a comparatively excessive charge so that just about a wholly completely different set of species could also be current in adjoining areas, relying on the character of the barrier between them. Making this much more of a problem, in some situations the barrier seems to be the low-lying valley as a substitute of a mountain ridge. For instance, in Colombia, Anolis heterodermus Duméril 1851 was lately cut up into eight distinct species (Morena-Arias et al. 2023). Each the varied mountain ranges (Cordillera) in addition to the Magdalena River valley seem to behave as limitations isolating the varied lineages into distinct species. Therefore, by way of making an attempt to establish the Anolis in a few of these areas, correct geographic location is a should.
—Third, there are solely eight species (12%) of non-native anoles in all of South America (together with the A-B-C islands and Trinidad and Tobago). All eight happen in northern South America and just one or two (A. porcatus and maybe A. sagrei) happen elsewhere in South America. Distinction this with the 16 or so species of launched anoles in North America, which have made in depth inroads in locations just like the southeastern United States, southern Mexico, and sure of the Caribbean Islands. These eight launched species would be the concentrate on half 3 of this sequence.
One of many attention-grabbing issues in regards to the excessive diploma of endemism of the anoles of northern South America is how rapidly it in all probability occurred. Andean orogeny started maybe 20 million years in the past (mya) and lasted till about 8 mya. Therefore, the variety variations between the occidental (western) and oriental (jap) areas of nations comparable to Ecuador, Colombia, and Venezuela are notable for his or her close to completeness. For comparability, the Laramide orogeny that created the Rocky Mountains occurred between 80-55 mya; the Alleghanian orogeny that created the Appalachian Mountains occurred between 325-260 mya. Therefore, the temporal arrival of the Andes created spatial limitations to gene circulate and geographic complexity that’s mirrored within the excessive beta variety of Anolis each inside and between areas of South America.
In conclusion, northern South America is the variety hotspot for anoles. The anole species north of the Amazon are dominated by native, extremely endemic species that usually have geographic ranges restricted to a single nation, a single valley, and even one slope of a single mountain ridge. Furthermore, there are comparatively few launched anoles in South America with most of these launched to the A-B-C islands and Trinidad and Tobago. Given that just about no species of anoles cross the Orinoco River or Andes Mountains and only a few species happen extensively within the Carribean or Central America, the anoles of northern South America characterize a reasonably separate and distinct fauna when in comparison with different geographic areas throughout the distribution of Anolis.
Literature cited:
Moreno-Arias, R. A., Méndez-Galeano, M. A., Beltrán, I., & Vargas-Ramírez, M. 2023. Revealing anole variety within the highlands of the Northern Andes: New and resurrected species of the Anolis heterodermus species group. Vertebrate Zoology, 73, 161-188
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