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Species Name:    Spirorbis spp.
Common Name:                  None



Kingdom Phylum/Division: Class: Order: Family: Genus:
Animalia Annelida Polychaeta Canalipalpata Serpulidae Spirorbis

Calcareous tubes of the serpulid polychaete Spirorbis sp. Photo courtesy Paul Adams.

Species Name: 
SpirorbisVerrill spp.

Common Name:

Despite the fact that organisms of the genus Spirorbis are abundant within Florida's marine and estuarine waters, information at the species level of resolution is greatly lacking.

A number of Spirorbis species have been reported in the literature, including Spirorbis borealis, S. corrugata, and S.spirillum (Gibson et al. 2005). Current understanding of the systematics of the genus is poor. Most authors continue to identify specimens widely reported from Florida simply as Spirorbis or Spirorbis sp. Spirorbis spirillum, , is now placed within an entirely different genus, Dexiospira.

Species Description:
Spirorbis is a diverse genus of small, tube-building serpulid polychaetes. All members build and inhabit coiled tubes that attach to submerged vegatation, rocks, dock pilings, or other substrata. The tubes may be either dextrally or sinestrally coiled, depending on the species (Fauchald 1978). Anatomical details of the animals themselves differ by species, but all are soft-bodied worms occupying coiled shell tubes. A short abdominal segment connects to a somewhat broadened thorax topped with (typically ten) stiff tentacles modified as feeding appendages. One of the tentacles is modified into a saucer-shaped operculum used to seal off the tube and protect the animal from predators and desiccation.

Tube formation in Spirorbis is accomplished through calcium secreting glands in the peristomium of the animal (Hedley 1956).

Potentially Misidentified Species:
Identification of any Spirorbis specimens to species level is difficult, even for trained taxonomists. The literature abounds with questionable or errant species designations.


Regional Occurrence:
The genus Spirorbis as a whole occurs across a very broad distributional range of latitudes. For example, specimens identified as S. borealis have been collected from Iceland south to Florida. Species-specific distributional information is currently lacking.

IRL Distribution:
Spirorbis occurs on suitable macrophyte habitats and some other hard substrata throughout the IRL.


Age, Size, Lifespan:
Most species of Spirorbis have body lengths of around 3 mm.

NOAA NBI collection records from Florida Bay and adjacent coastal waters reveal field densities of Spirorbis to vary between 25 and 1,600 individuals/m2, with most records reporting densities of 100/m2 or less.

A survey of the literature indicates that reproductive strategies differ somewhat among the members of genus Spirorbis. Much of the genus appears to exhibit hermaphroditism with some species self-fertilizing and others cross-fertilizing, and most protectively brood their eggs and larvae (Bergan 1953, Gee and Williams 1965, Potswald 1968, Ghiselin 1969). Some species appear to rely on external fertilization while others appear to utilize internal fertilization (Potswald 1968).

Reproductive seasonality appears variable among species and geographical locations as well. Surveys by Rothlisberg (1974) indicate La Jolla, CA, populations of S. marioni produce and brood eggs year-round, and those by Mook (1983) suggest Indian River Lagoon Spororbis spp. reproduce throughout the year as well. Seasonal reproductive peaks appear correlated with water temperature, and periodic peaks in spawning and larval release may correlate with tidal extremes (Rothlisberg 1974). utilize internal fertilization (Potswald 1968).

In Spirorbis spirorbis (Daly and Golding 1977, Rice 1978) and possibly other Spirornis species, sperm storage and delayed fertilization at the time of egg release obviate the need for synchronized spawning in functional males and females within the population.

Spirorbis spirillum broods its eggs and larvae until the larvae are released to the water column for a brief (minutes) period before settling (Dirnberger 1990, Bell et al. 2001). Potswald (1968) notes that brood protection within genus Spirorbis occurs either within the parental tube or within a modified opercular structure. Larvae accumulate environmental calcium and secrete it at settlement during tube formation (Nott and Parkes 1975).

Mook (1983) reports the year-round settlement of large numbers of Spirorbis spp. in the Indian River Lagoon. Mook (1981) noted a higher incidence of settlement onto experimental tiles that had been recently scraped clean and suggested these tiles suitably mimicked naturally-occurring freshly opened primary space that the species is adapted to rapidly colonize.


The genus as a whole occurs across a very broad range of temperatures. Information regarding the temperature tolerance of individual species of Spirorbis is scarce.

Examination of NOAA NBI collection records for Spirorbis in Florida Bay and adjacent coastal waters reveals most animals were collected from oceanic salinities. Populations occurring elsewhere in Florida (e.g., in the IRL) persist at estuarine salinities somewhat lower than these, but there is little published information indicating the ability of these animals to withstand extreme salinity fluctuations.


Trophic Mode:
Like most serpulid polychaetes, Spirorbis are filter-feeding animals. They use a crown of stiff tentacles to capture particles from the surrounding water.

Spirorbis and other seagrass and macrtoalgal epibiota is opportunistically preyed upon by various grazers of marine macrophytes (Wressing and Booth 2007). The calcareous tube dwellings offers a limited degree of protection from smaller or less robust predators.

Associated Animals:
Active preference by settling Spirorbis for surfaces coated by microbial films has been reported (Walters et al. 1997). DeSilva (1962) reports preferential settlement of S. tridentatus onto stones with bio-organic films. Several other authors have reported preferences of settlement-stage Spirorbis for specific macroalgae (e.g., Stebbing 1972, MacKay and Doyle 1978, Al-Ogily 1985). Fenical (1993) notes that these associations may be associated exclusively with the macroalgae, with the presence of bacteria on algal surfaces, or both. The presence of adult conspecifics has also been shown to increase settlement rates in S. borealis and S. pagastecheri (Knight-Jones 1951, Walters et al. 1997).

Mook (1983) reports that Spirorbis sp. settled onto the tests (body surface) of the sea squirt Styela plicata during the course of field experiments conducted in the Indian River Lagoon.

Spirorbis spp. has also been reported as an epibiont on sick and injured sea turtles in southwest Florida (Thompson 1997).

Bell et al. (2001) describe Spirorbis spirillum as a tube-building epibiont typically found attached to seagrass blades. Turtle grass (Thalassia testudinum) and manatee grass (Syringodium filiforme) are the most heavily colonized of Florida's seagrass species. Other species of Spirorbis typically attach to fucoid brown algae, e.g., as reported for S. borealis in the vicinity of Woods Hole, MA (Schively 1897). Spirorbis also occurs on pelagic Sargassum macroalgae in the Guld Stream (Weis 1968).

Less commonly, Spirorbis settles onto red mangrove (Rhizophora mangle) prop roots (Bingham 1992).

Dirnberger (1990) reports that Spirorbis spirillum larvae disproportionately settle on the bases of growing Thalassia blades and actively avoid epiphytic algae associated with the distal portion of the blades. Bell et al. (2001) report that S. spirillum densities on Thalassia seagrass blades was reduced at grassbed edges compared to the seagrass bed interior, and suggested hydrodynamic alteration of food supply or larval recruitment as explanations.


Special Status:

Economic/Ecological Importance:
Although the overall ecological importance of Spirorbis is not known, it is a broadly distributed and diverse polychaete genus. The Integrated Taxonomic Information System (ITIS) recognizes some two dozen valid species within the genus.


Al-Ogily SM. 1985. Further experiments on larval behavior of the tubicolous polychaete Spirorbis inornatus L'Hardy & Quivreux. Journal Experimental Marine Biology and Ecology. 86:285-298.

Bell SS, Brooks RA, Robbins BD, Fonseca MS, and MO Hall. 2001. Faunal response to fragmentation in seagrass habitats: Implications for seagrass conservation. Biological Conservation 100:115-123.

Bergen P. 1953. On the anatomy and reproduction biology in Spirorbis Daudin. Nytt Mag. Zool., 1:1-26.

Bingham BL. 1992. Life histories in an epifaunal community: Coupling of adult and larval processes. Ecology Vol 73(6): 2244-2259.

Daly JM and DW Golding. 1977. A description of the spermatheca of Spirorbis (L.) (Polychaeta:Serpulidae) and evidence for a novel mode of sperm transmission. Journal Marine Biological Association 57: 219-227.

DeSilva PHDH 1962. Experiments on the choice of sub- strate by Spirorbis larvae (Serpulidae). Journal Experimental Biology 39: 483-490.

Dirnberger JM. 1990. Benthic determinants of settlement for planktonic larvae: Availability of settlement sites for the tube-buildng polychaete Spirorbis spirilum (Linneaus) settling onto seagrass blades. Journal of Experimental Marine Biology and Ecology 140:89-105.

Fauchald K 1977. The Polychaete Worms. Definitions and Keys to the Orders, Families and Genera. Natural History Museum of Los Angeles County, in conjunction with the Allan Hancock Foundation, University of Southern California Science Series 28. 199 p.

Fenical W. 1993. Chemical studies of marine bacteria: developing a new resource. Chem. Rev. 93: 1673-1683.

Gee JM and GB Williams. 1965. Self and cross-fertilization in Spirorbis borealis and S. pagenstecheri. Journal Marine Biological Association United Kingdom, 45: 275-285.

Ghiselin MT. 1969. The evolution of hermaphroditism among animals. Quarterly Review of Biology, Vol. 44(2), pp. 189-208.

Gibson RN, Atkinson RJA, and JDM Gordon. 2005. Oceanography and Marine Biology: An Annual Review. CRC Press. 600 p.

Hedley RH. 1956. Studies of serpulid tube formation. II. The calcium secreting glands in the peristomium of Spirorbis, Hydroides, and Serpula. Quarterly Journal Microscopic. Science. 97: 421-427.

Ivany LC, Portell RW, and DS Jones. 1990. Animal-plant relationships and paleobiogeography of an Eocene seagrass community from Florida. PALAIOS, Vol. 5,(3), pp. 244-258.

Knight-Jones EW 1951. Gregariousness and some other aspects of the settling behavior of Spirorbis. Journal Marine Biological Association, United Kingdom. 30: 201-222.

MacKay TFC and Doyle RW. 1978. An ecological genetic analysis of the settling behavior of a marine polychaete: Causes of settlement patterns in a serpulid polychaete I. Probability of settlement and gregarious behavior. Heredity 40: 1-12.

Mook DH. 1981. Effects of disturbance and initial settlement on fouling community structure. Ecology, Vol. 62(3): 522-526.

Mook D. 1983. Responses of common fouling organisms in the Indian River, Florida, to various predation and disturbance intensities. Estuaries 6:372-379.

Nott JA and KR Parkes. 1975. Calcium accumulation and secretion in the serpulid polychaete Spirorbis spirorbis at settlement. Journal Marine Biological Association, United Kingdom 55: 911-923.

Potswald HE. 1968. The biology of fertilization and brood protection in Spirorbis (Laeospira) morchi. Biological Bulletin, Vol. 135(1) pp. 208-222.

Rice SA. 1978. Spermatophores and sperm transfer in spionid polychaetes: Transactions of the American Microscopical Society, Vol. 97(2 ) pp. 160-170.

Rothlisberg PC. 1974. Reproduction in Spirorbis (Spirorbella) marioni Caullery & Mesnil (polychaeta: Serpulidae). Journal of Experimental Marine Biology and Ecology 15:285-297.

Schively, MA. 1897. The anatomy and development of Spirorbis borealis Proceedings of the Academy of Natural Sciences of Philadelphia, Vol. 49 pp. 153-160.

Shulman JSW. 1968. Fauna associated with pelagic sargassum in the Gulf Stream. American Midland Naturalist, Vol. 80 (2) pp. 554-558.

Stebbing ARD 1972. Preferential settlement of a bryozoan and serpulid larvae on the younger parts of Laminaria fronds. Journal Marine Biological Association, United Kingdom. 52: 765-772.

Thompson M. 1997. Epibionts on the carapaces of sick and injured sea turtles in southwest Florida during a time of frequent red tide. Unpublished undergraduate thesis, New College, FL.

Walters MG, Hadfield, KA. del Carme. 1997. In the importance of larval choice and hydrodynamics in creating aggregations of Hydroides elegans (Polychaeta: Serpulidae) vertebrate Biology Vol. 116 (2) pp. 102-114.

Wressnig A and DJ Booth. 2007. Feeding preferences of two seagrass grazing monacanthid fishes. Journal of Fish Biology 71:272-278.

Report by:  J. Masterson, Smithsonian Marine Station
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Page last updated: October 1, 2008