Unveiling a hitherto monotypic crustacean coral endoparasite: diversity and morphology of the genus Zibrowia Grygier, 1995 (Thecostraca: Ascothoracida) through integrative taxonomy

Abstract Zibrowia is a little-known genus of ascothoracidan endoparasites that live in the gastral cavity of solitary dendrophylliid corals. Before this study, all known specimens of Zibrowia were assigned to a single species, Z. auriculata , based on traditional morphological characters, although they were found in different locations and different hosts . The present study is based on an integrative approach and examines the morphological and molecular divergence of Zibrowia collected in Tubastraea corals in Taiwan and reveals three new species, Zibrowia mucronata sp. nov., Zibrowia caudata sp. nov., and Zibrowia trifurcata sp. nov. These three species are diagnosed based on the morphology of the carapace, the number of paired thoracopods and the abdomen structures. Based on sequence divergence in COI and the results obtained from Automatic Barcode Gap Discovery (ABGD), automatic partitioning analysis (ASAP), Poisson tree processes (PTP) model and Generalized Mixed Yule Coalescent (GMYC) methods, the samples of Zibrowia collected in Taiwan were assigned to four groups, corresponding to the three newly identified Zibrowia species and one that is undescribed, Zibrowia sp. This suggests that Zibrowia is a complex of cryptic species and that its hidden diversity in the Indo-Pacific should be further explored using an integrative taxonomy approach.