Cliona carpenteri var. gracilis Hentschel, 1909

Van Soest, Rob W. M., 2024, Correcting sponge names: nomenclatural update of lower taxa level Porifera, Zootaxa 5398 (1), pp. 1-122 : 74-75

Cliona carpenteri var. gracilis Hentschel, 1909

Cliona carpenteri var. gracilis Hentschel, 1909: 387 (no illustration).

The variety was erected by Hentschel from Shark Bay, West Australia, approximate coordinates 25.92°S 113.48°E, depth 3 m (type material ZMH, (ZMB fragment, but number cited by Hooper & Wiedenmayer 1994: 132 is incorrect), slide ZMB 4496). The variety differs from the typical variety described by Hancock (1867: 241, pl. VIII fig. 4, from Mazatlan, Pacific coast of Mexico, holotype 2 slides in the Hancock Museum reg. nrs 4.15.11 and 12, cf. redescription in Ŗtzler & Stone 1986: 661, figs. 4a–b) in having only a single category of microspined acanthoxeas measuring 72–90 x 3 µm versus two categories, 130 x 10 and 63 x 4 µm in the typical variety. Carballo et al. (2004) described C. carpenteri from the type locality citing microspined acanthoxeas ‘on average 84 x 4 µm’, but in their SEM plate of the spicules they clearly show two size categories (their Fig. 19B). Hentschel (1909) emphasized the slimness of the microspined acanthoxeas in the present variety, but the difference is only evident in the larger category (130 x 10 µm vs 72–90 x 3 µm).

The name combination of the present variety is a junior primary homonym of Cliona gracilis Hancock, 1867 . Junior primary homonyms are permanently invalid (ICZN art. 57.2). Both are also currently assigned to genus Pione Gray, 1867 and thus Hentschel’s name must be replaced (ICZN art. 59.1), despite the fact that C. gracilis is currently considered a junior synonym of Cliona vastifica ( Hancock, 1849) . Hooper & Wiedenmayer (1994: 132) reassigned the variety to the synonymy of the species C. carpenteri . The status of Pione carpenteri populations cited around the world (Pacific coast of North and South America, Central West Atlantic, Indian Ocean) makes it arbitrary to distinguish subspecific taxa. Nevertheless, the admittedly small differences between the type specimens of the two varieties supports recognizing a separate taxon in West Australia, contra to Hooper & Wiedenmayer’s (1994) unargued synonymy assignment. A forthcoming revision may reach the outcome that regional populations are better given the status of subspecies. I propose Pione carpenteri subsp. hentscheli nom.nov. for the present variety.