Bellactis Dube, 1983

Delgado, Alonso, Larson, Paul, Sheridan, Nancy & Daly, Marymegan, 2023, Bellactis lux n. sp. (Cnidaria: Anthozoa: Actiniaria: Aiptasiidae), a new sea anemone from the Gulf of Mexico, Zootaxa 5353 (4), pp. 379-392 : 381-382

Genus Bellactis Dube, 1983

Diagnosis: (after Dube, 1983 with changes in bold) Aiptasiidae with broad base. Column smooth, thin, with 2–4 rows of cinclides in mid-column; distinction between scapus and capitulum generally distinguishable in living specimens. Mesogleal marginal sphincter weak, alveolar, may be absent in small individuals. Oral disc lobed. Tentacles very numerous, stout. More mesenteries proximally than distally. Mesenteries irregularly arranged; six or seven pairs of perfect mesenteries; first and second cycles fertile. Retractor muscles broad but restricted. Acontia numerous. Asexual reproduction via longitudinal fission and pedal laceration occurs in at least some members. Hosts Symbiodinaceae spp. in gastrodermis.

Cnidom: spirocysts (tentacles), basitrichs (pedal disc, column, tentacles, actinopharynx, filaments, acontia), and microbasic b-mastigophores (column) and microbasic p-amastigophores (pedal disc, tentacles, actinopharynx, filaments, acontia).

Explanation of changes: The diagnosis above incorporates information from previous descriptions and revisions ( Grajales and Rodríguez 2014; Ocaña et al. 2015) and information from the species described here. Per these additional records, we note that the base of many specimens is regular and oval, rather than irregular as described by Dube (1983), although this feature varies among specimens and depends on the state of contraction. Likewise, the column is variable in height, from squat to elongate, depending on contraction. Whether the column is divided into a capitulum and scapus is not known for B. caeruleus , but in B. ilkalyseae and B. lux , this distinction is visible in living specimens (see Discussion). Tentacles are stout and may appear short relative to the column when the animal is extended. Retractor muscles restricted to diffuse: Grajales and Rodriguez (2014: Fig. 18A) show sections through the type species B. ilkalyseae that are wide but restricted, and we see the same morphology in the new species described here and in B. caeruleus . Asexual reproduction via longitudinal fission has been documented in B. ilkalyseae (see OLIVEIRA and Gomes 2005) and pedal laceration is reported for B. caeruleus (see Ocaña et al. 2015), so Dube’s (1983) statement that they are not capable of asexual reproduction is incorrect and has been corrected in the genus diagnosis. Previous accounts of B. ilkalyseae and B. caeruleus describing irregularly-placed tentacles may be attributable to asexual reproduction, as might the variation in the shape of the pedal disc. We have amended the identity of the photosymbionts to reflect contemporary taxonomy of that lineage.