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 .