Filogranula Langerhans 1884

Filogranula Langerhans, 1884

Type-species: Filogranula gracilis Langerhans, 1884

Generic diagnosis (after ten Hove & Kupriyanova 2009). Tube white, opaque, with elaborate peristomes; keel present. Granular overlay absent. Operculum with chitinous endplate, central additional spines may present. Peduncle cylindrical, smooth, wings absent; inserted as 2nd dorsal radiole on either side. Opercular constriction present (but absent in F. stellata (Southward, 1963)). Pseudoperculum absent. Up to seven radioles per lobe arranged in semi-circles. Inter-radiolar membrane and stylodes absent. Branchial eyes may be present. Mouth palps not observed. Collar usually not divided into lobes (= unlobed), trilobed in a few taxa; with straight edge continuous with short thoracic membranes, reaching up to 2nd chaetiger. Tonguelets absent. Seven thoracic chaetigerous segments, 6 of which uncinigerous. Collar chaetae fin-and-blade and limbate capillaries. Apomatus chaetae present. Thoracic uncini saw- or saw-to-rasp-shaped with 12–14 teeth in profile view, up to five teeth in a transverse row above blunt, gouged underneath anterior peg (e.g., dental formula P:5:3:3:2:1:1:1:1:1:1:1:1:1). Triangular depression absent. Abdominal chaetae short, flat triangular with wide distal denticulate blade on anterior and midabdominal chaetigers, long capillaries on posterior chaetigers. Abdominal uncini rasp-shaped. Achaetous anterior abdominal zone present. Posterior glandular pad absent.

Remarks. Zibrowius (1983) and Kupriyanova (1993a) noticed that the genera Chitinopoma Levinsen, 1884 and Filogranula are very similar in general opercular and chaetal structure, as well as in the length of thoracic membranes. Ten Hove & Kupriyanova (2009) mention that additional studies are needed to determine whether these two genera should be synonymized.