Simplex, Topsent, 1892

Manconi, Renata, Cadeddu, Barbara, Ledda, Fabio & Pronzato, Roberto, 2013, An overview of the Mediterranean cave-dwelling horny sponges (Porifera, Demospongiae), ZooKeys 281, pp. 1-68 : 10-11

Darwinella simplex Topsent, 1892 Fig. 5

Darwinella simplex Topsent, 1892: 27.

Description.

Growth form encrusting. Surface conulose bearing a reticulate dermal membrane with fibre tips supporting conules. Colour in vivo "rouge carmin" as reported by the author, bright red. Dendritic skeleton arising from a basal spongin plate with the main fibres (up to 4 mm in height, 60-160 µm in diameter) evidently laminated and free of foreign material, with variably dense granular axial pith. Fibres. Horny spicules triactines free or connected to the main skeleton (rarely each to one another), with actins ca. 1.1-1.25 mm in length and 45-50 µm in diameter, gradually tapering towards the sharp tips. Rays linear, usually 3, rarely 2 or 4. Spicules sometimes with pith.

Habitat.

Cave, rocky bottom, coralligenous community. Bathymetric range 3-100 m.

Mediterranean caves.

Lerici Cave (Ligurian Sea); Secca delle Formiche-Vivara Cave (Central Tyrrhenian Sea); Taccio Vecchio 1 Cave-Lampedusa* (Sicily Channel) ( Pulitzer-Finali and Pronzato 1976, 1980; Pronzato and Manconi 2011). Recorded as Darwinella australiensis .

Remarks.

Pronzato (1975) considered the Mediterranean species Darwinella simplex Topsent, 1892 as junior synonym of the Pacific species Darwinella australiensis Carter, 1885 (senior synonym) sharing diagnostic morphological traits as also focused by Topsent (1892). A re-evaluation of original descriptions vs. old and new materials allow us to consider Darwinella simplex Topsent, 1892 a valid species. The validity of Darwinella simplex solves the extremely disjunct Australian-Mediterranean geographic pattern and matches the hypothesis of a species complex.