Eurypon Gray, 1867

Cavalcanti, Thaynã, Santos, George Garcia & Pinheiro, Ulisses, 2018, Description of three species of Eurypon Gray, 1867 (Raspailiidae: Demospongiae: Porifera) from the Western Atlantic and a name to replace the the secondary homonym Eurypon topsenti, Zootaxa 4388 (1), pp. 89-101 : 91

Genus Eurypon Gray, 1867

Synonymy. For synonymy list see Hooper (2002).

Type species: Hymeraphia clavata Bowerbank, 1866 (by monotypy).

Definition. Typically encrusting Raspailiidae with microcionid skeletal structure in which fiber nodes ascend from the basal layer of spongin ( Hooper 2002).

Diagnosis. Encrusting, massive or digitate growth forms. Surface hispid, even, granular or conulose. Encrusting species have a microcionid choanosomal skeletal structure with a basally compressed layer of spongin fibres lying on the substrate producing small spongin-fibre nodes echinated by acanthostyles, and radially disposed extra-axial skeleton composed of subectosomal styles standing perpendicular to and embedded in basal fibres. Massive species have slightly axially compressed plumose tracts of extra-axial styles, often forming fanlike bundles, and tracts lightly echinated by acanthostyles. Extra-axial styles may be partially or entirely spined (Acantheurypon). Ectosomal specialization present (s.s.) or absent; if present ectosomal skeleton consists of fine monactinal (or diactinal) spicule brushes surrounding single protruding extra-axial styles. Structural megascleres consist of 1–2 categories of styles or (sub-)tylostyles (rarely modified to oxeas); echinating acanthostyles microcionid-like, typically long and with subtylote bases, or verticillate. Several species have raphides in trichodragmata. Oxychaetes are found in some species (emended from Hooper 2002, changes are in bold).

Remarks. Hooper (2002) indicates the presence of styles and (sub-)tylostyles, echinating acanthostyles and raphides as the spicule complement. However, different spicules have been recorded for the genus in the present study. Oxychaetes are exclusive of E. oxychaetum sp. nov. Additionally, the presence of verticillate acanthostyles (found only in E. verticillatum sp. nov.) is also a new character for diagnosing the genus.