Boa, Linnaeus, 1758

Gonzalez, Rodrigo Castellari, Lima, Lorena Corina Bezerra de, Passos, Paulo & Silva, Maria José J., 2024, The good, the bad and the boa: An unexpected new species of a true boa revealed by morphological and molecular evidence, PLoS ONE (e 0298159) 19 (4), pp. 1-29 : 23

Is there cryptic diversity in the genus Boa ?

Currently, cryptic species could represent a substantial fraction of biodiversity and, consequently, such phenomena are calling attention and being discovered at a speeding pace [ 92, 93]. Nevertheless, it is known that the diversity of cryptic species is still underestimated [ 94] or even misunderstood [ 95]. For instance, at first the case of Boa spp. seems to fit well to general processes associated with concentration of cryptic diversity, such as: recent divergence in combination with a certain level of morphological stasis. Notwithstanding, many of currently recognized species present apparently fixed diagnostic features mostly based on external morphology (e.g., colour tones and patterns). As a rule, such character systems have been disregarded if compared to other sources of phenotypic characters (e.g., male geniatlia and osteological features) in several groups of snakes (see [ 96]). However, for all other extant boid the colour patterns have proven to hold interesting phylogenetic signals [ 97 – 100]. By following definitions of cryptic species [ 95], we believe that most taxa currently recognized as full species along the Boa constrictor Clade (i.e., Boa atlantica sp. nov., Boa nebulosa , and Boa orophias ) are not cryptic at all, since, even if tenuous, they present unambiguous morphological diagnosis from each other congener, including the nominal form. In fact, our results suggest that a plethora of phenotypic data examined here are broadly congruent with the molecular evidence, not the contrary, in an integrative taxonomy approach, despite recent diversification revealed by short branches recovered within the group. Therefore, we highlight the importance of studying several sources of phenotypic evidence, even if there is a suggestion of high levels of polymorphism. However, as pointed out by Lee & Palci [ 101] if morphology is to be employed to its full potential, biologists need to start scrutinising phenotypes in a more objective fashion, models of phenotypic evolution need to be improved, and approaches for analysing phenotypic traits together with genomic data need to be refined.