Myxilla mariana var. polysigma Topsent, 1904

Van Soest, Rob W. M., 2024, Correcting sponge names: nomenclatural update of lower taxa level Porifera, Zootaxa 5398 (1), pp. 1-122 : 71

Myxilla mariana var. polysigma Topsent, 1904

( Fig. 7I )

Myxilla mariana var. polysigma Topsent, 1904: 169 , pl. XIV figs. 10.

The variety was described by Topsent from the Azores, collected by the Prince Albert 1 er Monaco Cruises at Station 584, 38.5167°N 26.821°W, depth 845 m (type in MOM, holotype slide MNHN DT 919). It is a thin, soft encrustation on dead coral, yellowish in alcohol. It differs from the typical variety of Ridley & Dendy (1886: 472 from subantarctic Indian Ocean Marion Island, Prince Edward Islands, Challenger Exped., 46.83°S 37.8°E, depth 92–137 m, holotype BMNH 1887.5.2.108) in having a mucronate condition at one of the endings of the ectosomal spicules and a more hastate condition at the opposing end (where the typical variety has more properly tylotes), more strongly curved anchorate isochelae than the less curved ones of the typical variety, and in the longer sigmas, 70 vs 57 µm. Differences are small, but in view of the geographic separation (lower bathyal North Atlantic vs. more shallow occurrence in the southern Indian Ocean), I propose to elevate the present variety to a subspecies, to be named Myxilla (Ectyomyxilla) mariana subsp. polysigma Topsent, 1904 , distinct from the typical subspecies Myxilla (Ectyomyxilla) mariana subsp. mariana Ridley & Dendy, 1886 .

Figures

FIGURE 7. A. Polymastia isidis var. simplex Hentschel, 1914: pl. V fig. 3, B. Asbestopluma biserialis var. californiana De Laubenfels, 1935: fig. 5, C. Esperiopsis macrosigma var. novaezealandiae Dendy, 1924: pl. XIII figs. 14–20, D. Halichondria flabellifera Bowerbank, 1882: pl. VII figs. 4–10, E. Hymedesmia (Ectyodesmia) mutabilis var. costata Topsent, 1928: pl. VIII figs. 20, 22–23, F. Iophon flabellodigitatus var. gaussi Hentschel, 1914: pl. VI fig.10, G. Iophon pluricornis var. trullifera Hentschel, 1914: pl. VI fig. 9, H. Lissodendoryx isodictyalis var. paucispinosa Topsent, 1928: pl. VIII fig. 11, I. Myxilla mariana var. polysigma Topsent, 1904: pl. XIV figs. 10, J–K. Myxilla rosacea var. japonica Ridley & Dendy, 1887, J. habitus pl. XXVI fig. 3, K. spicules XXVII fig. 8, L. Pytheas rosea var. laevigata Descatoire, 1969b: fig. 4, M. Stylostichon dendyi var. robustum Topsent, 1928: pl. X fig.1.