Molecular Evidence for Cryptic Speciation in the <i>Cyclophorus fulguratus</i> (Pfeiffer, 1854) Species Complex (Caenogastropoda: Cyclophoridae) with Description of New Species

<div><p>A high degree of intraspecific variation, both genetic and in shell morphology, of the operculate land snail <i>Cyclophorus fulguratus</i> (Pfeiffer, 1854) suggests that its classification as a single species warrants reconsideration. We sequenced two nuclear (18S and 28S) and two mitochondrial (16S and COI) genes of 46 <i>C. fulguratus</i> specimens and used them to estimate the phylogeny and to determine the validity of species boundaries. Molecular phylogenetic analyses revealed the presence of three lineages corresponding to three geographically disjunctive populations of <i>C. fulguratus</i> in Thailand. Likelihood tests of topologies significantly supported the non-monophyly of the <i>C. fulguratus</i>–complex and Bayesian species delimitation analysis significantly supported the potential representation as distinct species of these three lineages. Discriminant function analysis based on geometric-morphometrics of shell shape allowed for significant distinction of these three candidate species, although they revealed a considerable degree of overlap of shell shape reflecting their crypsis morphologically. The diagnostic characters are provided by color pattern, pattern of protoconch and pattern of jaw. In conclusion, the results support that the <i>C. fulguratus</i> s.l., as currently recognized, consists of three distinct species in Thailand: <i>C. fulguratus</i> s.s., <i>C. rangunensis</i> and <i>C. abditus</i> sp.nov., which are described herein.</p>