The three members of the lecanicephalidean tapeworm family Eniochobothriidae are unusual among tapeworms in that they lack a vagina and possess a series of expanded proglottids forming a trough at the anterior end of their body. They exclusively parasitise cownose rays of the genus Rhinoptera (Myliobatiformes: Rhinopteridae). New collections from six of the nine known species of cownose rays from the waters off Australia, Mexico, Mozambique, Senegal, Taiwan and the United States (off Mississippi, Louisiana and South Carolina) yielded eight new species and a new genus of eniochobothriids. Here we erect Amiculucestus, gen. nov. and describe six of the eight new species – four in the new genus and two in Eniochobothrium – expanding the number of genera in the family to two and the number of described species in the family to nine. Morphological work was based on light and scanning electron microscopy. The tree resulting from a maximum likelihood analysis of sequence data for the D1–D3 region of the 28S rDNA gene for 11 species of eniochobothriids supports the reciprocal monophyly of both genera. The mode of attachment to the mucosal surface of the spiral intestine of the host was investigated using histological sections of worms in situ. These cestodes appear to use the anterior trough-like portion of their body, which consists of an unusual series of barren proglottids, rather than their scolex, to attach to the mucosal surface. Based on our new collections, we estimate that the total number of eniochobothriids across the globe does not exceed 27 species.

Alpha taxonomy is fundamental for many biological fields. Delineation of the species boundary, however, can be challenging in a species complex, where different species share a similar morphology and diagnostic characters may not be available. In this context, integrative approaches that incorporate molecular and morphological data sets, and account for speciation history can be helpful to alpha taxonomy. Different approaches to species delimitation based on different assumptions are complementary and by integrating the results from multiple approaches we can generate a more reliable and objective taxonomic decision. In this study, we applied three molecular approaches to species delimitation and inferred the demographic history based on an isolation with migration model to test a morphologically based taxonomic hypothesis for the Cylindera pseudocylindriformis complex. We discuss the association between genetic divergence and microhabitat specialisation, and further corroborate that C. subtilis sp. nov. is a valid new species by integrating the results from model-based species delimitation and the genealogical divergence index. We argue that genetic endemism can occur at a small geographic scale, even in a winged insect like tiger beetles. Our results also indicated that there may still be undocumented species diversity of Taiwanese Cylindera remaining to be discovered.

Unravelling the evolutionary history of taxa requires solid delimitation of the traits characterising these. This can be challenging especially in groups with a highly complex taxonomy. The squat lobster family Munididae contains more than 450 species distributed among 21 genera, Munida being the most speciose (~300 species). Previous phylogenetic studies, based on a small part of the diversity of the group, have suggested polyphyletic origins for Munida and the paraphyly of Munididae. Here, we use an integrative approach based on multi-locus phylogenies (two mitochondrial and three nuclear markers) paired with 120 morphological characters, to resolve taxonomic and evolutionary relationships within Munididae. Our study covers ~60% of the family’s known diversity (over 800 specimens of 291 species belonging to 19 of the 21 genera collected from the Atlantic, Indian and Pacific oceans). Using this information, we confirm the validity of most genera, proposing new ones in cases where the genetic analyses are compatible with morphological characters. Four well-defined munidid clades were recovered, suggesting that new genera should be erected in the currently recognised Munididae (three for the genus Agononida and eleven in Munida), and the genus Grimothea is resurrected. A key to all genera of the family is presented. Molecular clock estimates and ancestral biogeographic area reconstructions complement the taxonomic profiles and suggest some explosive diversification within Munididae during the Cretaceous and the Palaeogene. Further anagenetic events and narrow sympatry accounting for changes in distribution indicate a more limited dispersal capacity than previously considered. Our study unravels how diversification may occur in deep waters and further highlights the importance of the integrative approach in accurately delineating species in understanding the history of a family and the factors driving the evolution.