Halichondria panicea var. hemispherica Dendy, 1905

Van Soest, Rob W. M., 2024, Correcting sponge names: nomenclatural update of lower taxa level Porifera, Zootaxa 5398 (1), pp. 1-122 : 81

Halichondria panicea var. hemispherica Dendy, 1905

Halichondria panicea var. hemispherica Dendy, 1905: 146 (no illustration).

The variety was described by Dendy along with H. panicea var. megalorhaphis ( Carter, 1881, originally as Amorphina ) from Gulf of Mannar, Sri Lanka, approximate coordinates 9°N 79°E (wet holotype BMNH 1907.2.1.43). Both varieties were remarked as having oxeas at the surface arranged vertically, not tangentially as is the case in the ‘typical variety’ of H.(H.) panicea ( Pallas, 1766: 388, as Spongia , wet neotype from Burnham-on-Crouch, Essex, UK, approximate coordinates 51.64°N 0.967°E, shallow depth, BMNH 1964.6.8.6, cf. Erpenbeck & Van Soest 2002: 802). Thus, it is clear that the var. hemispherica cannot be a Halichondria , but likely a member of the genus Topsentia Berg, 1899 , to which also Amorphina megalorhaphis is currently assigned. Dendy stated that the var. hemispherica shared spiculation, confused skeletal arrangement, and “full-grown spicules measuring up to 1 mm ” with var. megalorhaphis , but the two varieties differed in shape, hemispherica being smooth and convex with oscules grouped, and megalorhaphis being encrusting with lobose and digitiform processes and scattered oscules. I propose for the time being that the var. hemispherica is retained as a distinct species to be named Topsentia hemispherica ( Dendy, 1905) , until the possible conspecificity with Topsentia megalorhaphis ( Carter, 1881) , originally from Bass Strait, Southeast Australia, has been investigated.

I do not follow Burton (1959: 257–258) in his sweeping synonymization of a large number of records of different name combinations, including the present H. p. var. hemispherica under a single ‘super’ species Amorphinopsis megalorhaphis ( Carter, 1881) . Detailed justifications for these synonymy assignments are entirely lacking and the overall argument provided by Burton for the long list of synonyms (all allegedly being members of an Indo-West Pacific Halichondria panicea -like widespread species) is outright insufficient. Moreover, his choice of genus for this species is erroneous as the type species of Amorphinopsis , A. excavans Carter, 1887 , has small ectosomal styles in addition to the oxeas (cf. Erpenbeck & Van Soest 2002). If such a ‘super’ species would have existed, the proper genus for it would have to be Topsentia , not Amorphinopsis .