Morphological and molecular tracing of two ornamental vampire crabs (Decapoda: Sesarmidae) from Central Java

Geosesarma dennerle and G. hagen are the two most popular species of vampire crabs in the ornamental crab trading.These sympatric species typically occupy similar habitats, but variations in carapace coloration often lead to their trade under different trade names, suggesting the same or newly identified species.Therefore, this study aimed to investigate the genetic differences between G. dennerle and G. hagen using DNA analysis based on COI and 16S rRNA markers from specimens collected in Central Java Province, compared to species obtained from the natural habitat (holotype's locality, Cilacap Regency, Central Java).The results of the phylogenetic analysis showed a monophyletic relationship with well-supported ML and BPP values in some infra clades, while the basal clades were lowsupported.The low genetic divergence between closely related species G. dennerle and G. hagen showed recent separation.However, haplotype network analysis showed a closer connection in the population of G. hagen and a larger divergence between trade and wild population in G. dennerle.This study suggested the presence of a potential new species in the wild, with promising exploration and description in their natural habitats.