Filograna Berkeley, 1835

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 42-43

10. Filograna Berkeley, 1835

( Fig. 17)

Type species: Filograna implexa Berkeley, 1835

Number of species: 1

Worms form open aggregates consisting of large numbers of small whitish tubes, circular in cross-section. Granular overlay and keels absent. A pair of membranous spoon-shaped opercula on first unmodified pinnulate radioles. Radioles arranged into semi-circles, up to 4 radioles per lobe. Branchial eyes absent. Interradiolar membrane and stylodes absent. Prominent prostomium with ocellar clusters. Mouth palps present. 6–12 thoracic chaetigerous segments. Collar trilobed, tonguelets between ventral and lateral collar lobes absent. Thoracic membranes long, forming apron. Collar chaetae fin-and-blade ( Fig. 17A) and limbate. Apomatus chaetae present. All uncini rasp-shaped with up to 10 teeth in profile, 2–4 teeth in a transverse row; anterior fang pointed ( Fig. 17B). Triangular depression absent. Achaetous anterior abdominal zone present, short. Abdominal chaetae flat narrow geniculate with rounded teeth along edge ( Fig. 17C). Long posterior capillary chaetae and glandular pad absent.

Remarks. The genus Filograna has been attributed by e.g., Mörch (1863; as Filigrana ) and Hartman (1959) to Oken (1815). However, Oken used filograna as species name in the combination “ Clymene filograna , Serpula filograna ”; the species name was elevated to generic rank by Berkeley (1835). The nominal genera Filograna and Salmacina are distinguished mainly by the presence of two (rarely one) membranous opercula in the former and absence of an operculum in the latter. Some authors consider them distinct genera ( Iroso 1921, Fauvel 1927, Pillai 1960, Straughan 1967b), whereas others treat them as a single species ( McIntosh 1923, Faulkner 1929, Day 1955, 1967). More recent authors ( Nelson-Smith 1967, Gee 1963, Zibrowius 1968a, 1973b, Uchida 1978, Kupriyanova & Jirkov 1997) regard operculate and nonoperculate forms to be separate species within the genus Filograna . Nogueira & ten Hove (2000) gave an extensive discussion and synonymy and adapted the heuristic view that the operculate cold-temperate Atlantic Filograna better be kept separate from the non-operculate ubiquitous Salmacina .

Filograna implexa M. Berkeley, 1835 . Weymouth, English Channel, UK; cold temperate-subtropical Atlantic, Mediterranean; other locations doubtful.