Sessile vestimentiferan tubeworms inhabit chemosynthetic environments, such as hydrothermal vents or methane seeps. The new species described here, Lamellibrachia judigobini sp. nov. and Escarpia tritentaculata sp. nov., both from seep-dwelling genera, were discovered at a unique ‘hydrothermal seep’ of the Mid-Cayman Spreading Centre. We show an incredible habitat flexibility of a single Lamellibrachia species and the genus Escarpia, and historic biogeographic connections to the eastern Pacific for L. judigobini and the eastern Atlantic for E. tritentaculata.

The remarkable similarity among three species of sponges from the Amazon reefs, seemingly classified in two distinct orders, necessitated an integrative assessment of the phylogenetic affinities. These species were all found to belong in a highly supported clade together with the type species of the poecilosclerid Coelocarteria (Demospongiae, Porifera). Since this clade did not nest more closely to any poecilosclerid family in particular, we propose to erect the monogeneric Coelocarteriidae fam. nov.

Snorkel snails of the genus Rhiostoma have considerable variation in shell morphology. We used two mtDNA fragments, morphological characters and shell geometric morphometrics to infer phylogenetic relationships. Results revealed four distinct clades and four separate species under the name R. housei.