Filogranula Langerhans, 1884

Genus Filogranula Langerhans, 1884 View in CoL

Type species. Filogranula gracilis Langerhans, 1884 View in CoL

Generic diagnosis (from ten Hove & Kupriyanova, 2009). Tube white, opaque, with elaborate peristomes; keel present. Granular overlay absent. Operculum with chitinous endplate, may have additional spines in the centre. Peduncle cylindrical, smooth, without wings; inserted as 2 nd dorsal radiole on one side. Pseudoperculum absent. Radioles arranged in semi-circles, up to 7 per lobe. Inter-radiolar membrane and stylodes absent. Radiolar eyes may be present. Mouth palps not observed. Seven thoracic chaetigerous segments. Collar generally non-lobed (may be trilobed) with entire edge, continuous with short thoracic membranes ending at 2 nd thoracic chaetiger. Tonguelets absent. Collar chaetae fin-and-blade and limbate. Apomatus View in CoL chaetae present. Thoracic uncini saw- or saw-to-rasp-shaped with 12–14 teeth in profile, up to 5 teeth in a row above anterior peg, blunt, gouged underneath. Triangular depression absent. Abdominal chaetae short, flat triangular with wide distal denticulate blade; abdominal uncini rasp-shaped. Achaetous anterior abdominal zone present. Long posterior capillary chaetae present. Posterior glandular pad absent.

Remarks. Zibrowius (1983) and Kupriyanova (1993b) 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 and Kupriyanova (2009) mentioned that additional studies are needed to determine whether these two genera should be synonymised. The most recent multigene molecular phylogeny of Kupriyanova et al. (2023) showed that F. stellata and C. serrula are sister groups, thus supporting the hypothesis.