Cryptic diversity and species delimitation in the Cryptanthus pickelii L.B.Sm. complex (Bromeliaceae) from morphometrics and molecular markers

The genus Cryptanthus Otto & A.Dietr. (Bromeliaceae—Bromelioideae) is endemic to Brazil and comprises 68 species, with a diversity centre in the Atlantic Forest. Cryptanthus pickelii, C. alagoanus, and C. pirambuensis do not present well-defined taxonomic delimitation and constitute the Cryptanthus pickelii complex. In this study, morphometric and molecular approaches were employed to delimit the complex and characterize the structure and genetic diversity of six populations studied. Multivariate morphometric analyses of 24 vegetative and reproductive characters were performed on 82 specimens. In addition, six nuclear microsatellite loci were genotyped in 120 individuals of the complex. The morphometric results showed four morphotypes. The Bayesian analysis revealed three most likely groups, indicating that C. alagoanus and C. pirambuensis are two names given to the same species. Following a reassessment of conservation status, we recognize C. pickelii as threatened and C. alagoanus as Critically Endangered, leading us to indicate priority areas for the establishment of conservation units. Distinct genetic structuring was detected in two populations of C. alagoanus. We present the first record of C. pickelii for the state of Paraíba. We also reinforce the hypothesis of hybrid speciation in a population of C. alagoanus with C. zonatus. In addition, we propose the synonymization of C. pirambuensis with C. alagoanus.