Antholoba fabiani sp. nov. (Actiniaria, Metridioidea, Antholobidae fam. nov.), a new species and family of sea anemone of the southwestern Atlantic, Brazil

DURÁN-FUENTES, JEFERSON A.; GONZÁLEZ-MUÑOZ, RICARDO; DALY, MARYMEGAN; STAMPAR, SÉRGIO N.

Marine Biodiversity

Springer Nature

Lugar: Berlin; Año: 2024 vol. 54 p. 1 - 17

1867-1616

The genus Antholoba Hertwig, 1882 (Actiniaria, Enthemonae) is characterized by the presence of short and numeroustentacles, a folded oral disc in lobes or cup-shaped with an expanded distal part, transversely wrinkled body wall surface, avery long mesogloeal sphincter, parietobasilar muscles poorly developed, and the absence of acontia. Currently, the genusAntholoba is classified within the family Actinostolidae Carlgren, 1893 (superfamily Actinostoloidea Carlgren, 1932) andcomprises two valid species: A. achates (Drayton in Dana, 1846) which have been recorded in Antarctica, the southwesternAtlantic, and the southeastern-western Pacific; and A. perdix (Drayton in Dana, 1846) which is distributed in the northwesternAtlantic, including the Gulf of Mexico. In recent collections along Ubatuba Bay in northern São Paulo, Brazil, we foundspecimens of a third, unknown species, which exhibits morphological and genetic differences from the only other speciesrecorded from that place, A. achates (Drayton in Dana, 1846). Additionally, we examined five specimens of A. achatescollected in Penha, Santa Catarina State, for morphological comparison. Our phylogenetic analyses, using molecular data,affirm the difference between the two species. Furthermore, the resultant phylogenetic trees recover the species of the genusAntholoba as a sister group to the acuticulate clade, within the superfamily Metridioidea, instead of within Actinostoloidea.We describe the material from Ubatuba as a new species, A. fabiani sp. nov., providing information and photographs of itsexternal and internal anatomy, as well as cnidom, along with sequences of mitochondrial (12S, 16S, and COIII) and nuclear(18S and 28S) markers. Additionally, we propose placing the genus Antholoba within Metridioidea, and introduce the newfamily Antholobidae fam. nov.