Citizen science and integrative taxonomy allowed us to reveal great diversity within Caribbean annelids. We combine molecular (i.e. COI and 18S phylogeny, distances and species discrimination), morphological and biogeographical data to describe one species, and report on two other species that remain unnamed as these belong to complexes that cannot be resolved in light of current data. Our results stress the relevance of always considering morphology and biogeographical distribution together with gene analyses when trying to resolve the taxonomy of cryptic species complexes.

Myanmar has become one of the most important amber deposits of Cretaceous Insecta material over the past two decades. However, the fossil Cantharidae from the Burmese amber is still a poorly investigated group, with many taxa remaining unknown. In this study, we integrate comparative morphology and geometric morphometrics methods to unveil a new genus and three new species, and reconstruct a morphology-based phylogeny. These results will help us to better understand the morphological and specific diversity of Burmite cantharids.

Syllid marine worms are well known for spectacular bioluminescent rituals, using green light for mate attraction. This courtship behaviour has been considerably investigated, but the origin and evolution of light production are poorly known. Here, we used phylogenetics and ancestral state reconstructions to investigate the evolutionary relationships of luminous syllids and trace the origins of bioluminescence. Our analyses recover two main lineages and suggest that bioluminescence evolved independently twice within the group, shedding light on the evolutionary history of luminous syllids.

Theromyzon (Hirudinea) has a history of taxonomic confusion caused by repeated mischaracterisation of morphological features. We bring partial order to this confusion by inferring a phylogeny and robustly investigating the morphology of newly collected specimens, representing most of the known North American diversity. We demonstrate that there are at least five species present in North America, including a taxon that does not conform to any previously published description. We describe this species under the name Theromyzon tigris sp. nov.

Blind Metagonia spiders in Galápagos lava tubes have been thought to be relicts whose epigean ancestors had disappeared from the archipelago. Two epigean species were found on Galápagos during a collecting trip in 2019 but whether these were closely related to the cave-dwelling species or distantly related species recently introduced from the mainland remained unclear. Our analyses consistently resolve all Galápagos Metagonia together as a monophyletic group, divided into an epigean clade and a hypogean clade. Each species is restricted to an individual island (Isabela or Santa Cruz; with one possible exception), suggesting that the epigean Metagonia species are native rather than introduced.