We have been remiss here at AA in not reporting on a recent monograph in Novitates Caribaea (the journal of the Museo Nacional de Historia Natural of the Dominican Republic) by Köhler and Hedges dividing the Hispaniolan green anoles into sixteen species, up from the previously recognized four. Specifically, Anolis chlorocyanus is split into four species, A. coelestinus into five species, and A. aliniger is subdivided into six species. Poor A. singularis remains as it is.
The analysis is based on mitochondrial DNA and morphological characters. The monograph is available online and should be consulted for the fine details. Appended below are the abstract and the heart of the methods.
Say what you may about the proliferation of new species (and word on the street is that this will not be the last word on green anole species diversity), some of the new species are spectacular in appearance and certainly there is more variation in this group than many may have realized.
We revise the species of green anoles (i.e., the species related to Anolis aliniger, A. chlorocyanus, and A. coelestinus) occuring on Hispaniola. Based on our analyses of morphological and molecular genetic data we recognize 16 species of green anoles, eight of which we describe as new species (A. apletolepis sp. nov., A. chlorodius sp. nov., A. divius sp. nov., A. eladioi sp. nov., A. gonavensis sp. nov., A. leucodera sp. nov., A. prasinorius sp. nov. and A. viridius sp. nov.) and three of which are raised from subspecific to species level (A. cyanostictus, A. demissus and A. pecuarius) and one is resurrected from synonymy with A. chlorocyanus (A. peynadoi). Because the six syntypes of A. chlorocyanus (MNHN 785, 787, 2007.2066–09) are conspecific with the only available syntype of A. coelestinus (i.e., MCZ 3347), we have petitioned the International Commission of Zoological Nomenclature (ICZN) to use its plenary power to set aside the type status of the syntypes of Anolis chlorocyanus and to allow the designation of a neotype in order to stabilize the current and long established usage of the names A. chlorocyanus and A. coelestinus. For each species we provide a standardized description of external morphology, color descriptions in life, color photographs in life, description and illustration of hemipenis morphology (if available), distribution maps based on the specimens examined, comments on the conservation status, and natural history notes. Finally, we provide a dichotomous key for the identification of the 16 species of green anoles occuring on Hispaniola.
And here’s how they did it:
For this study, we have examined a total of 787 specimens of green anoles from Hispaniola. Head length was measured from the tip of the snout to the anterior margin of the ear opening. Snout length was measured from the tip of the snout to the anterior border of the orbit. Head width was determined with the broad tips of the calipers aligned with the levels of posterior margin of eye and supralabial scales, respectively, with the calipers held in a vertical position relative to the head. Dorsal and ventral scales were counted at midbody along the midline. Tail height and width were measured at the point reached by the heel of the extended hind leg. Subdigital lamellae were counted on Phalanges II to IV of Toe IV of the hind limbs, and separately on distal phalanx. We considered the scale directly anterior to the circumnasal to be a prenasal. Abbreviations used are AGD (axilla–groin distance), dorsAG (number of medial dorsal scales between levels of axilla and groin), dorsHL (number of medial dorsal scales in one head length), HDT (horizontal diameter of tail), HL (head length), HW (head width), IFL (infralabials), IP (interparietal plate), SAM (scales around midbody), ShL (shank length), SL (snout length), SO (subocular scales), SPL (supralabial scales), SS (supraorbital semicircles), SVL (snout–vent length), TL (tail length),VDT (vertical diameter of tail), ventrAG (number of medial ventral scales between levels of axilla and groin), and ventrHL (number of medial ventral scales in one head length). In reporting the frequencies of character states, we used the following terminology (Köhler submitted): if a character state was present in more than 65% of the examined specimens, we coded it as “usually”; <65% but >20% “commonly”; <20% but >5% “occasionally”; and <5% “exceptionally”. The use of size categories also follows Köhler (2014): (1) small: <50 mm SVL; (2) moderate-sized: 50–60 mm SVL; (3) moderately large: 60–80 mm SVL; (4) large: 80–110 mm SVL; (5) giant: >110 mm SVL.
As lines of evidence for species delimitation, we apply a phenotypic criterion (external morphology: coloration, morphometrics, and pholidosis) and a criterion for reproductive isolation (genetic distinctness of the cytochrome B and ND2 genes). Sequences from 77 ingroup and two outgroup taxa were analyzed (a total of 2217 aligned sites). Alignments (MUSCLE) and best-fit model selection were performed in MEGA 6.06 (Tamura et al., 2013). A maximum likelihood (ML) analysis was performed using MEGA 6.06), unpartitioned, using the evolutionary model GTR + I + Γ. Gaps were treated as missing data. All parameters for the ML analyses were estimated by the program during the run. Branch support in the trees was provided by standard bootstrap analysis (2,000 replicates). A Bayesian phylogenetic analysis using MrBayes 3.2.2 (Ronquist et al., 2012) also was performed, also using the GTR + I + Γ model. The Bayesian analysis was set to two parallel runs for five million generations, sampled every 100 generations, each run employed three heated and one cold chain, with a temperature parameter of 0.10. The first 10% of samples were discarded as burn-in. Convergence was assessed by the standard deviation of split frequencies (< 0.01 in all cases).