Buizer and Van Soest, 1977
Species Overview
Mycale (Carmia) micracanthoxea Buizer and Van Soest, 1977 is a brownish or yellowish grey, thinly encrusting soft sponge, showing in situ a clear venal pattern of superficial canals. It is unusual in the genus for possessing tiny micracanthoxeas. It is suspected to be a fouling species with a preference for occurrence in manmade environments.
Taxonomic Description
Colour: Brownish or yellowish grey alive taking the colour of the substratum in thinner specimens, with orange-yellow spots in time of reproduction. In alcohol it is greyish white.
Shape, size and consistency: Thinly encrusting, thickness about 2 mm. Only when attached to erect substrates such hydroid colonies it may become up to 2 cm thick. Horizontal substrate cover several cm2. Surface of the sponge smooth and punctate (Mycale micracanthoxea detail); microtuberculate when dried. No obvious oscules, but in live specimens clearly visible superficial canals lead to slightly elevated small contracted oscules.
Spicules: (Mycale micracanthoxea dra) (Mycale micracanthoxea sp) Megascleres of one type: subtylostyles of the "mycalostyle" form with faintly constricted necks: 256-270-285 by 7-7.5 µm.
Microscleres : Palmate anisochelas, sigmas, toxas and micracanthoxeas; no raphides. Anisochelas occur in two size categories: 20-23-32 and 13-16-20 µm. Sigmas occur in two size categories: 58-73-89 and 19-22-24 µm. Toxas occur in two size categories: 100-110-120 and 13-16-20 µm. Micracanthoxeas: 7-8 µm. The latter are only reliably identified using the Scanning Electron Microscope.
Skeleton: No special tangential skeleton, which conforms to the subgenus Carmia . Tracts of subtylostyles rise up from the substrate and pierce the organic ectosome. Many individual subtylostyles are found loosely strewn among the tracts. Microscleres are likewise scattered among the tracts and in the organic ectosome.
Reproduction: Viviparous; embryos are found between June and November, larvae have been observed in August and October. Larvae (Mycale micracanthoxea la) are yellow with a white posterior pole, approximately 360 µm in size, uniformly ciliated except for a completely bare posterior pole (Wapstra and Van Soest, 1987).
Ecology: Substrates are harbour piles, oyster and mussel shells, barnacles, ascidians and hydroids. Shallow water.
Distribution: First reported from the SW of The Netherlands; subsequently the species was found in Algecirras Bay, SW Spain (Carballo et al., 1994).
Etymology: The name refers to the spined microxeas.
Type specimen information: Holotype: Zoological Museum of Amsterdam, ZMA POR. 4282 (Mycale micracanthoxea holotype).
Remarks
Unpublished material with micracanthoxeas from the Canary Islands may also be allocated to this species (Cruz, pers. comm.). A sister species with largely similar characters has been reported from British Columbia (Mycale bamfieldensis ).
Source: Buizer and Van Soest, 1977