Protula Risso, 1826

Kupriyanova, Elena K., Sun, Yanan, Ten Hove, Harry A., Wong, Eunice & Rouse, Greg W., 2015, Serpulidae (Annelida) of Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 275-353 : 304

Genus Protula Risso, 1826

Type-species. Protula rudolphi Risso, 1826 , junior synonym of Serpula tubularia Montagu, 1803 .

Diagnosis. (from ten Hove & Kupriyanova 2009). Tube white, opaque, may be up to 2 cm across and 40 cm long, (semi-)circular in cross-section, longitudinal keels and flaring peristomes absent. Operculum and pseudoperculum absent. Radioles arranged in two semicircles to a spire of up to 6 whorls, up to 320 per lobe ( P. superba Moore, 1909 ). Inter-radiolar membrane present. Branchial eyes may be present. Stylodes absent. Mouth palps present. Seven thoracic chaetigerous segments. Collar trilobed, tonguelets absent. Thoracic membranes long and wide, with undulating edge, forming ventral apron across anterior abdominal segments. Collar chaetae limbate. Apomatus chaetae present. Thoracic and abdominal uncini rasp-shaped with approximately 30 teeth in profile, up to 6 rows of teeth above and continuing onto elongated rounded peg. Thoracic triangular depression absent. Abdominal chaetae sickle-shaped, with finely denticulate blades, may be retro-geniculate in some taxa. Achaetous anterior abdominal zone absent. Long posterior capillary chaetae present. Posterior glandular pad present.

Remarks. In their recent review of the taxonomy of serpulid genera, ten Hove & Kupriyanova (2009: 81) called Protula the most problematic serpulid taxon. Often authors do not even try to identify specimens to species level as evidenced by over 60 literature records of Protula spec . in ten Hove’s literature database. The phylogenetic basis for this genus is ill-defined and based on negative characters, such as lack of an operculum, lack of special collar chaetae and mostly lack of any characteristic ornamentation of the tube (although Protula diomedeae Benedict, 1887 has a fairly recognizable tube, and some others too may be determined by tubes only). In Australia, two species are currently commonly reported: the large forms with distinct spiralled radioles (white or white and yellow in colour) as P. bispiralis ( Savigny, 1822) and all smaller forms as P. palliata ( Willey, 1905) . For an extensive discussion see Ben-Eliahu & ten Hove (2011: 44–62). The real number of species is unknown and it is most likely impossible to determine without a dedicated morphological and molecular revisionary study.