Protula Risso, 1826

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 81-83

34. Protula Risso, 1826

( Fig. 39)

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

Number of species:?23

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 ). Inter-radiolar membrane present. Branchial eyes may be present. Stylodes absent. Mouth palps present. 7 thoracic chaetigerous segments (however, see remarks). 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 ( Fig. 39A, C). Thoracic triangular depression absent. Abdominal chaetae sickle-shaped, with finely denticulate blades ( Fig. 39B), may be retro-geniculate in some taxa. Achaetous anterior abdominal zone absent. Long posterior capillary chaetae present. Posterior glandular pad present.

Remarks. The genus Protula is the most problematic serpulid taxon and it has been pointed out that the phylogenetic basis for this genus is ill-defined (ten Hove 1984). The generic characters are based mainly on the negative characters, such as lack of operculum, lack of special collar chaetae and any characteristic ornamentation of the tubes. Because reliable species-level morphological characters are missing, species in the genus Protula have been described based on small differences in the shape of collar, number and arrangement of radioles, and even body and tube size. These differences may have been caused by varying state of preservation, variation in age, a different way of figuring and interpretation by the authors. Moreover, some species distinctions have been based on presumed differences in chaetation. For instance, Uchida (1978) relies heavily on literature data on absence or presence of Apomatus chaetae, a character used for generic distinction in his “subfamily Protulinae ”. However, ten Hove & Pantus (1985) showed that Apomatus chaetae are extremely difficult to discern in the thick bundles of limbate chaetae, and if present occur at best in the chaetigers 5–7 in the Mediterranean Protula tubularia sensu auct. Within one population, specimens with and without Apomatus chaetae may occur, as well as specimens with or without thoracic uncini. Thus, the scanty literature data should be viewed with more caution than was done by Uchida (1978). For instance, his genus Paraprotula was based on the absence of the character “capillary” chaetae in thoracic segments in literature descriptions of Protula . However, “capillary” chaetae do occur in all serpulid genera we observed, including Protula . A further difference according to Uchida would be the abdominal chaetae, sickle shaped in Protula , retro-geniculate (“with a notch at the base of the free margin”) in Paraprotula apomatoides ; however, this retro-geniculate chaetal type is known from Protula balboensis as well. Therefore we included his taxon Paraprotula apomatoides in the genus Protula . The number of 9 thoracic chaetigers, in our opinion, is insufficient to maintain a separate genus, Salmacinopsis , for the nominal taxon setosa , it would fit in the genus Protula .

A very necessary revision of the genus should be based upon a comparison of all available types and as well as a statistical study of variability and should be confirmed with molecular data. Some of the names given below as “valid” had been synonymised in the past, on the misconception that widespread distributions of polychaetes were very common.

1. Protula alba Benedict, 1887 , West Indies; perhaps see P. longiseta

2. Protula alberti Fauvel, 1909 , off Azores; bathyal

3. Protula americana McIntosh, 1885 , Nova Scotia, Eastern Canada

4. Protula antennata Ehlers, 1887 , off South Florida; bathyal; compare P. longiseta

5. Protula apomatoides ( Uchida, 1978) , Sabiura, South Japan

6. Protula appendiculata Schmarda, 1861 , Jamaica; questionable

7. Protula atypha Bush, 1905 , California, Hawaii; compare P. superba

8. Protula balboensis Monro, 1933 , Gulf of Panama, Pacific Colombia,? Brazil

9. Protula bispiralis ( Savigny, 1820) , widely distributed in the Indo-West Pacific, New Zealand; probably complex of species

10. Protula diomedeae Benedict, 1887 , Eastern USA; shelf depths to bathyal; compare P. submedia

11. Protula intestinum ( Lamarck, 1818) , Mediterranean-Atlantic, southern U.K.

12. Protula longiseta Schmarda, 1861 , West Indies; compare P. alba and P. antennata

13. Protula lusitanica McIntosh, 1885 , off Portugal; bathyal; indeterminable, specimen lost

14. Protula media Stimpson, 1854 , Eastern Canada, Arctic

15. Protula pacifica Pixell, 1912 , West Canada, North Japan Sea

16. Protula palliata ( Willey, 1905) , Sri Lanka, Indo-West Pacific

17.? Protula setosa ( Bush, 1910) , Bermuda Islands; the generic and specific status of Salmacinopsis setosa is uncertain, but most probably Protula

18.? Protula soofita Ben-Eliahu, 1976 , Gulf of Elat (= Gulf of Aqaba); generic attribution uncertain, shows affinities with Vermiliopsis as well

19. Protula submedia Augener, 1906 , West Indies; bathyal; compare P. diomedeae

20. Protula superba Moore, 1909 , Gulf of California, California; compare P. atypha

21. Protula tubularia ( Montagu, 1803) , England, Atlantic, questionably worldwide

22. Protula tubularia anomala Day, 1955 , South Africa; probably a full species

23. Protula tubularia caeca Imajima, 1977 , Ogasawara Islands, Japan; probably a full species.