Serpula Linnaeus, 1758

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 93-95

41. Serpula Linnaeus, 1758

( Fig. 46)

Type-species: Serpula vermicularis Linnaeus, 1767 , designated by Heppell, 1963.

Number of species: 29

Tube white, pink, orange, or yellowish, opaque; (semi)circular to trapezoidal in cross-section, rarely polygonal; longitudinal keels, peristomes, a hyaline outer layer or granular overlay may be present. Operculum soft to cartilaginous, funnel shaped with crenulated edge (fused radii). Peduncle smooth, cylindrical, without wings; inserted just below and between first and second dorsal radiole on one side. In large specimens the insertion outside the normal radioles, seemingly the first radiole. Radioles arranged in semi-circles, up to 50 per lobe in larger species. Pseudoperculum and inter-radiolar membrane present. Branchial eyes may be present. Mouth palps present, though only to be observed with histological techniques ( Orrhage, 1980). Stylodes absent. 7 (rarely up to 12) thoracic segments. Collar trilobed. Tonguelets absent, though wart-like protuberances may be present at base of cleft between ventral and latero-dorsal collar lobes. Thoracic membranes long, forming ventral apron across anterior abdominal segments. Collar chaetae bayonet-shaped ( Fig. 46A) and limbate. Apomatus chaetae absent. Uncini saw-shaped, with approximately 5 teeth, anterior fang simple pointed ( Fig. 46B). Thoracic triangular depression present. Abdominal chaetae flat trumpet-shaped with denticulate edge ( Fig. 46D); uncini similar to thoracic ones, smaller, anteriorly sawshaped but becoming rasp-shaped towards the pygidium, with up to 12 teeth in profile, up to 8 teeth in a row ( Fig. 46C). Achaetous anterior abdominal zone absent. Posterior capillary chaetae present. Posterior glandular pad absent.

Remarks. This is another serpulid genus that poses serious taxonomic difficulties. Although attribution of any given specimen to the genus Serpula is easy due to a very characteristic funnel-shaped operculum with rounded radii (but see below), the number of useful taxonomic characters within the genus is limited and their variability is not documented enough to ensure the validity of many described species (see discussion in ten Hove & Jansen-Jacobs 1984). Many of the original descriptions are very limited and vague, and the characters typical for all species of the genus (such as the presence of bayonet-chaetae and a funnel-shaped operculum) have been used for specific diagnoses. As a consequence, the nominal species S. vermicularis has been reported from Arctic to tropical conditions, neither ecologically nor biogeographically a likely distribution. Some nominal species were based on incomplete or juvenile specimens; juvenile Hydroides species , also characterised by an operculum with a single scalloped operculum only, were often attributed to Serpula too (ten Hove & Ben-Eliahu 2005). The most commonly used meristic character, the number of opercular radii, appears to have limited taxonomic value for discriminating species because of its population and ontogenetic variability ( Kupriyanova 1999). A much-needed revision of the genus is currently under way (Pillai, pers. com.), and the list of “valid” species below is tentative only. Unpublished field notes by ten Hove state that some larger Serpula species (i.e. S. cf. jukesii ) have thoracic membrane pockets similar to those found in Floriprotis , see also remarks to Floriprotis . Finally, a recent study by Kupriyanova et al. (2008) demonstrates that the traditional genus Serpula most probably is paraphyletic.

1. Serpula cavernicola Fassari & Mollica, 1991 , Messina, Italy; compare S. vermicularis -complex

2. Serpula columbiana Johnson, 1901 , incl. S. nannoides Chamberlin, 1919 , Puget Sound, North-West coast of Americas

3. Serpula concharum Langerhans, 1880 , Madeira, Atlantic-Mediterranean; other records probably belong to different species

4. Serpula crenata ( Ehlers, 1908) , Zanzibar, Indo-West Pacific; bathyal; possibly incl. S. sinica

5. Serpula granulosa Marenzeller, 1885 , Kagoshima and Enoshima, Japan, Indo-West Pacific

6. Serpula hartmanae Reish, 1968 , Bikini, Indo-West Pacific

7. Serpula indica Parab & Gaikwad, 1989 , India

8. Serpula israelitica Amoureux, 1976 , Haifa, Levant Basin

9. Serpula japonica Imajima, 1979 , Honshu, Japan; questionably Seychelles

10. Serpula jukesii Baird, 1865 , Indo-West Pacific

11. Serpula lobiancoi Rioja, 1917 , Mediterranean-Atlantic

12. Serpula longituba Imajima, 1979 , Honshu, Japan

13. Serpula maorica ( Benham, 1927) , New Zealand; doubtful fide ten Hove & Jansen-Jacobs (1984: 151)

14. Serpula nanhaiensis ( Sun & Yang, 2001) , South China Sea

15. Serpula narconensis Baird, 1865 , Narcon Island, Antarctica, subantarctic

16. Serpula oshimae Imajima & ten Hove, 1984 , Indo-West Pacific

17. Serpula pacifica ( Uchida, 1978) , Sabiura, Japan; questionable fide ten Hove (1984: 103–104) and Pillai & ten Hove (1994: 40, 100)

18. Serpula philippensis McIntosh, 1885 , Philippine Islands; bathyal; questionable

19. Serpula planorbis ( Southward, 1963) , Irish Sea; bathyal

20. Serpula rubens Straughan, 1967b , Queensland, New South Wales, Australia

21. Serpula sinica Wu & Chen, 1979 (in Wu, Sun & Chen 1979), South China Sea; possibly synonym of S. crenata

22. Serpula tetratropia Imajima & ten Hove, 1984 , Palau and Caroline Island

23. Serpula uschakovi Kupriyanova, 1999 , Gilderbrandt Island, Sea of Japan; Moneron, Sakhalin

24. Serpula vasifera Haswell, 1885 , Port Jackson, New South Wales, Australia

25. Serpula vermicularis Linnaeus, 1767 , Western Europe; and probably restricted to this area, not worldwide as reported

26. Serpula vittata Augener, 1914 , Sharks Bay, Australia; Indo-West Pacific

27. Serpula watsoni Willey, 1905 , Trincomalee, Sri Lanka; Indo-West Pacific

28. Serpula willeyi Pillai, 1971 , Pearl Banks, Sri Lanka

29. Serpula zelandica Baird, 1865 , New Zealand.