Integrative taxonomic study reveals three new species of Lebbeus White, 1847 (Decapoda: Caridea: Thoridae) from deep water in the Philippine Sea and provides insights into the phylogeny of this genus

Lebbeus White, 1847 is the most diverse and widespread genus in the caridean family Thoridae Kingsley, 1879. Species of the genus have adapted to various habitats, inhabiting from shallow to deep water (>3000 m), low latitudinal to polar regions, and with free-living to symbiotic lifestyles. In spite of recent studies, the phylogenetic position of Lebbeus within Thoridae and its internal phylogenetic relationships remain to be explored. In this study, three new species of Lebbeus recently collected from deep water in the Philippine Sea are described using an integrative taxonomic approach. The new species are formally named Lebbeus chunshengisp. nov., Lebbeus lizheisp. nov., and Lebbeus xinzhengisp. nov. herein. The molecular phylogenetic analyses led the authors to revise the internal grouping of Lebbeus, which has long been relied on the development of the pereopodal epipods. It has been clarified that characters derived from the rostrum and carapace better reflect the phylogeny, and this finding prompted us to propose four informal species groups within Lebbeus. Additionally, we tentatively uncovered the phylogenetic position of Lebbeus by reconstructing a backbone phylogeny of Thoridae based on genome-skimming sequencing data. Our phylogeny supports the recent divergence of Lebbeus and its sister-group relationship with Spirontocaris Spence Bate, 1888. However, more extensive taxon sampling is needed to elucidate the monophyly of each thorid genus. This work provides critical baseline data for the conservation and restoration of habitats in the region, and advances our understanding of the diversity of sponge-associated shrimps in deep-sea ecosystems of the Western Pacific. ZooBank: urn:lsid:zoobank.org:pub:F6B8185D-CCD5-45AE-850E-24A40B0B20AD.