Apomatus Philippi, 1844

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 27-29

1. Apomatus Philippi, 1844

( Fig. 8)

Type-species: Apomatus ampulliferus Philippi, 1844

Number of species: 7

Tube white, opaque, circular in cross-section, keels and collar-like rings absent. Granular overlay may be present. Operculum a soft membranous vesicle without endplate borne on unmodified pinnulated radiole. Opercular constriction may be present. Pseudoperculum may be present on unmodified radiole. Arrangement of radioles in semi-circles (may be up to ¾ of a circle), maximum number up to 40 per lobe in larger species. Inter-radiolar membrane present. Branchial eyes present in the form of ocellar clusters. Stylodes absent. Mouth palps present. 7 thoracic chaetigerous segments. Collar trilobed with smooth edge. Thoracic membrane long, forming ventral apron across anterior abdominal segments. Tonguelets between ventral and lateral collar lobes absent. Collar chaetae limbate, of two sizes (thus, in the classical terminology capillary and limbate). Apomatus chaetae present ( Fig. 8C, D). Thoracic uncini saw-to-rasp-shaped with approximately 30 teeth in profile, up to 3 (exceptionally 4) teeth in a row above and continuing onto peg; anterior peg very long, blunt, almost rectangular ( Fig. 8A, B). Ventral thoracic triangular depression absent. Abdominal chaetae sickleshaped with finely denticulate blades ( Fig 8E, F); uncini rasp-shaped with approximately 30 teeth in profile. Short achaetous anterior abdominal zone present. Posterior capillary chaetae present. Posterior glandular pad present.

Remarks. A controversy exists whether Protula and Apomatus should be regarded as separate genera (ten Hove & Pantus 1985) or synonymized under Protula ( Kupriyanova & Jirkov 1997) . The genera are separated mainly by the presence ( Apomatus ) or absence ( Protula ) of a soft vesicular operculum on an unmodified radiole. Hanson’s (1948a) study on the pattern of blood vessels showed that P. tubularia , A. ampulliferus , and A. similis are similar to each other, but dissimilar to P. intestinum . She proposed that these genera should be fused. However, ten Hove & Pantus (1985) studied over a 100 fresh specimens and found consistent differences in blood-vessel patterns between operculate and non-operculate specimens. They suggested that Protula and Apomatus are valid genera and that Hanson (1948a) mistook an Apomatus specimen that incidentally lost its operculum for P. tubularia . This controversy is yet to be resolved, probably with the aid of molecular genetics.

1. Apomatus ampulliferus Philippi, 1844 Mediterranean, Atlantic

2. Apomatus elisabethae McIntosh, 1885 New Zealand

3. Apomatus enosimae Marenzeller, 1885 South Japan, South China Sea

4. Apomatus geniculata ( Moore & Bush, 1904) , incl. A. timsii , North Pacific, Japan to California 5. Apomatus globifer Théel, 1878 , Arctic, Norway; probably see A. similis

6. Apomatus lilliei Benham, 1927 , North Cape, New Zealand

7. Apomatus similis Marion & Bobretzky, 1875 , Mediterranean Atlantic; probably includes A. globifer