Phorbas neptuni

(Schmidt, 1875)

Species Overview

Phorbas neptuni (Schmidt, 1875) is a thickly encrusting deep water sponge of uncertain status. Its surface is papillate but further details remain obscure. Its main distinguishing feature is the large size of the chelae which may reach 80-110 µm and the unguiferate nature of their alae. More information is needed.

Taxonomic Description

Colour: Yellowish-white in alcohol.
Shape, size, surface and consistency: Thickly encrusting to globular. Surface irregularly mamillated-papillate.
Spicules: (Hymeniacidon perarmatus spics)Megascleres : Tornotes oxea-like with elongated pointed ends: 500 x 11 µm. Acanthostyles in two not very clearly separated size categories; larger ones up to 1 mm x 20 µm or more, spined most desnsely on the head; smaller ones entirely spined, ca. 160 µm.
Microscleres : Chelae in two size categories, the larger technically probably arcuate but with long unguiferate teeth: 80-110 µm; smaller chelae normal-arcuate, ca. 40-50 µm.
Skeleton: Plumose tracts of tornotes end at the surface in brushes of tornotes; some are echinated by short acanthostyles. Long and short acanthostyles erect on the substrate.
Ecology: Deep water: 85-1300 m.
Distribution: Boreal-arctic: Norway, Faroes, Shetland, SW Ireland.
Etymology: Neptune was the Roman god of the sea.
Type specimen information: No type material in BMNH.

Remarks

This species and its assumed synonyms remain uncertain, as we have only a few old and incomplete descriptions. Apparently the size and form of the large chelae is characteristic and unique among the Western European Anchinoids, and for that reason the synonymy with Hymeniacidon perarmatus Bowerbank and Plumohalichondria microcionides Carter seems likely.
Source: Thiele, 1903