Pseudochitinopoma capensis

Description. TUBE: white, about 2.2 mm wide, with lumen of about 0.8 mm (Fig. 6 C – D). Triangular in crosssection, without wide flaring collar-like rings, attached throughout its length. Smooth medial keel present, lateral surfaces either rugose or corroded. Outer hyaline granular layer present. BRANCHIAE: each lobe with six radioles, arranged in semicircles to pectinately, not connected by interradiolar membrane. Pinnules increasing in length distally, about 18 pairs; terminal filament projecting beyond pinnules for 0.1 mm only. Section of radiole subtriangular. Mouth structures, prostomial and branchial eyes not observed. PEDUNCLE: smooth, almost circular in cross-section, inserted near medial line. Gradual transition between peduncle and operculum, with only a hint of a constriction. OPERCULUM: globular ampulla with a distal elongated convex endplate (Fig. 6 E – F). This distal cup chitinous, with faint longitudinal grooves, without internal partitions. Length of the operculum (ampulla + cap) about 1.5 mm, chitinous cap 1 mm, width 0.7 mm. COLLAR AND THORACIC MEMBRANES: collar low, with laciniate edge, probably artifact of preservation in tube; continuous with thoracic membranes, ending at chaetiger 3. THORAX: with collar chaetiger, and six uncinigerous chaetigers. Collar chaetae of two types: fin-and-blade (basal fin with 3 – 5 stout teeth at base of serrated blade, Fig. 6 G) and limbate. Subsequent chaetae limbate, of two sizes. Capillaries exceptionally small, 1 / 5 th – 1 / 10 th the size of the limbate ones. Apomatus - chaetae absent. Uncini along entire thorax saw-shaped, with 10 curved teeth above gouged, apparently bifurcated (likely gouged) peg (dental formula P: 1: 1: 1: 1: 1: 1: 1: 1: 1: 1, Fig. 6 H). Thoracic tori of similar size along thorax, triangular depression absent. ABDOMEN: abdominal chaetigers 70. Uncini not very well known, examination by SEM (Fig. 6 A) was only partially successful. Mid-abdominal uncini rasp-shaped, dental formulae P: 3: 2: 1: 2: 2:?:? :::, P: 3: 1: 2: 2: 2:?:? ::::, P: 3: 2: 2: 1:?:? :::: to saw-shaped apically (all apices obscured by epidermal fold and represented by:?:? :::: in the formulae), with flat peg, gouged underneath, and about 10 teeth. Chaetae trumpet-shaped, hollow, bordered with two rows of teeth, narrow and smoothly bent (Fig. 6 B). Capillary chaetae absent posteriorly. Pygidium bilobed. SIZE: length up to 14 mm. Width of thorax 0.6 mm. Branchiae and operculum 4 mm long. COLOUR: no records.

Remarks. According to ten Hove & Weerdenburg (1978: 101), this taxon does not belong in Ficopomatus, but rather in Chitinopoma, Chitinopomoides, or Pseudochitinopoma. Ten Hove & Kupriyanova (2009: 32) tentatively placed it in Chitinopoma. The actual material could not be located at the time, it only was re-found very recently (February 2011) in the collections of the Iziko South African Museum, Cape Town. Being common practice, Day removed a number of chaetigers from one side of the animal to enable his description: collar chaetae, about thoracic segments 3 – 5, and some abdominal chaetigers. Unfortunately, most of the other thoracic chaetae were broken too, but a total mount in glycerin of the animal did not reveal Apomatus chaetae in the posterior thoracic chaetigers. We may safely assume that they are absent. The above re-description, especially characteristic collar chaetae, hollow narrowly geniculate (true trumpet-shaped) abdominal chaetae and saw-shaped thoracic uncini with broad gouged peg, places this taxon clearly in the genus Pseudochitinopoma. The description agrees with those given by Day (1961: 552 – 553; 1967: 810 – 812) except for minor meristic differences: six pairs of radioles (Day mentioned seven), 70 abdominal chaetigers (Day: 64), 10 uncinal teeth (Day: 8).

Distribution. South Africa. Reproduction. Unknown.

Material studied. South Africa, Agulhas Bank, 34 ° 24 ' S, 21 ° 46 ' E, 18 m, dredge, UCT Ecological Survey, South Coast Dredging SCD 18, 14 February 1960, det. J. H. Day [manuscript name Ovopomatus capensis, see Marska (2004)] (IMCT 20901, Holotype). Scale: A, B — 10 µm, C, D — 1 mm, E, F — 0.5 mm, G, H — 10 µm.