Polychaetes, or bristle worms, are marine invertebrates of the Phylum Annelida. They are segmented worms and each body segment has a pair of fleshy protrusions called parapodia, which bear many bristles. They are a very common and diverse class of worms with over 10,000 species described so far. They are distributed throughout the world's oceans, being found from the intertidal to the deep sea. Some species are free-living within the epibenthos, while others are found in calcified tubes or burrowing in the sand and mud. Many of the polychaetes in NEMESIS have been introduced through ballast water aboard commercial ships, in the fouling community present on ships' hulls and recreational boats, or as hitchhikers with oyster imports. The impacts of exotic polychaetes are varied, with many having no reported impact, but some species can reach high densities and are known to increase erosion or foul aquaculture species and maritime equipment.

Polychaetes are one of the more difficult animal groups to categorize for invasion studies. Early taxonomists assumed that species were globally distributed, and varied greatly with environmental conditions. More detailed morphological and genetic studies have found many more species, including groups of morphologically similar, but genetically different species. Consequently, some previously reported invaders have turned out to be native or cryptogenic, while others have been discovered by genetic methods. Different invasion studies in the same region may have differing lists of polychaetes, and our NEMESIS list is likely to change with further collections and taxonomic studies.

We would like to thank Rolando Bastida-Zavala (Universidad del Mar, Mexico), Leslie Harris (Natural History Museum of Los Angeles County, USA), Erica Keppel (Smithsonian Environmental Research Center, USA), and Vasily Radashevsky (Russian Academy of Sciences) for their careful review and expert comments.

Species List

Alitta succinea
Amblyosyllis nigrolineata
Boccardiella ligerica
Branchiomma bairdi
Branchiomma coheni
Clymenella torquata
Diplocirrus SD1
Epigamia noroi
Ficopomatus enigmaticus
Ficopomatus uschakovi
Haplosyllis ohma
Hediste diadroma
Hediste diversicolor
Heteromastus filiformis species complex
Hobsonia florida
Hydroides elegans
Hydroides sanctaecrucis
Janua heterostropha
Laonome cf. calida
Marenzelleria neglecta
Marenzelleria viridis
Megasyllis nipponica
Myrianida convoluta
Myrianida pachycera
Myrianida pentadentata
Neodexiospira brasiliensis
Parasabella fullo
Polydora cornuta
Polydora hoplura
Polydora onagawaensis
Proceraea okadai
Protula balboensis
Pseudopolydora cf. kempi
Pseudopolydora paucibranchiata
Sabaco elongatus
Sabellastarte sp.
Spirobranchus kraussii
Spirobranchus minutus
Streblospio benedicti
Terebrasabella heterouncinata
Timarete punctata sp. A
Databases Overview| Chesapeake Bay | National Database |