Syllidae

Syllidae, commonly known as the necklace worms, is a family of small to medium-sized polychaete worms. Syllids are distinguished from other polychaetes by the presence of a muscular region of the anterior digestive tract known as the proventricle.

Syllid worms range in size from 2-3 mm to 14 cm. Most syllids are benthic organisms that transition to a pelagic epitoke for reproduction. They are found in all regions of the ocean, from the intertidal zone to the deep sea, and are especially abundant in shallow water.

They are found in a range of habitats, moving actively on rock and sandy substrates, hiding in crevices and among seaweeds, and climbing on sponges, corals, hydrozoans, seagrasses and mangroves. They are generalist feeders. A young Syllid was one of the first worms to be found with pollen from seagrass in its stomach, making it a possible pollinator.

The proventricle, Syllid worm's most distinctive anatomical feature, allows the worm to feed by sucking due to its pumping action. It also plays a role in hormone production, and thus the worm's sexual development. The proventricle is composed of strirated muscle cells with the longest known sacromeres among animals. The proventricle is usually visible through the body wall.

Syllis ramosa was the first polychaete discovered to have a branching body plan. Later, two species of Ramisyllis were discovered to have a branching body plan.

Subfamilies

 * Anoplosyllinae
 * Autolytinae
 * Eusyllinae
 * Exogoninae
 * Syllinae
 * Syllis
 * Syllis aciculigrossa (San Martín, 1990)
 * Syllis adamantea (Treadwell, 1914)
 * Syllis albae Álvarez-Campos & Verdes, 2017
 * Syllis albanyensis (Hartmann-Schröder, 1984)
 * Syllis alosae San Martín, 1992
 * Syllis alternata Moore, 1908
 * Syllis amica Quatrefages, 1866
 * Syllis amicarmillaris Simon, San Martín & Robinson, 2014
 * Syllis anoculata (Hartmann-Schröder, 1962)
 * Syllis antoniae Salcedo Oropeza, San Martín & Solís-Weiss, 2012
 * Syllis armillaris (O.F. Müller, 1776)
 * Syllis augeneri Haswell, 1920
 * Syllis barbata San Martín, 1992
 * Syllis bella Chamberlin, 1919
 * Syllis beneliahuae (Campoy & Alquézar, 1982)
 * Syllis benguellana Day, 1963
 * Syllis boggemanni San Martín, Álvarez-Campos & Hutchings, 2017
 * Syllis botosaneanui (Hartmann-Schröder, 1973)
 * Syllis brasiliensis McIntosh, 1885
 * Syllis breviarticulata Grube, 1857
 * Syllis brevicirrata McIntosh, 1908
 * Syllis brevicirris Hansen, 1882
 * Syllis broomensis (Hartmann-Schröder, 1979)
 * Syllis caeca Monro, 1933
 * Syllis castroviejoi Capa, San Martín & López, 2001
 * Syllis cerina Grube, 1878
 * Syllis cirrita Lee & Rho, 1994
 * Syllis columbretensis (Campoy, 1982)
 * Syllis compacta Gravier, 1900
 * Syllis corallicola Verrill, 1900
 * Syllis cornuta Rathke, 1843
 * Syllis crassicirrata (Treadwell, 1925)
 * Syllis cruzi Núñez & San Martín, 1991
 * Syllis curticirris Monro, 1937
 * Syllis danieli San Martín, 1992
 * Syllis deleoni Salcedo Oropeza, San Martín & Solís-Weiss, 2012
 * Syllis edensis (Hartmann-Schröder, 1989)
 * Syllis elongata (Johnson, 1901)
 * Syllis ergeni Çinar, 2005
 * Syllis erikae (Hartmann-Schröder, 1981)
 * Syllis fasciata Malmgren, 1867
 * Syllis ferrani Alós & San Martín, 1987
 * Syllis filidentata (Hartmann-Schröder, 1962)
 * Syllis garciai (Campoy, 1982)
 * Syllis gerlachi (Hartmann-Schröder, 1960)
 * Syllis gerundensis (Alós & Campoy, 1981)
 * Syllis glandulata Nogueira & San Martín, 2002
 * Syllis glarearia (Westheide, 1974)
 * Syllis golfonovensis (Hartmann-Schröder, 1962)
 * Syllis gracilis Grube, 1840
 * Syllis guidae Nogueira & Yunda-Guarin, 2008
 * Syllis heterochaeta Moore, 1909
 * Syllis hyalina Grube, 1863
 * Syllis hyllebergi (Licher, 1999)
 * Syllis joaoi San Martín, Álvarez-Campos & Hutchings, 2017
 * Syllis jorgei San Martín & López, 2000
 * Syllis kabilica Ben-Eliahu, 1977
 * Syllis karlae San Martín, Álvarez-Campos & Hutchings, 2017
 * Syllis kas Lucas, Sikorski & San Martín, 2018
 * Syllis komodoensis Aguado, San Martín & ten Hove, 2008
 * Syllis krohnii Ehlers, 1864
 * Syllis lagunae Tovar-Hernández, Hernández-Alcántara & Solís-Weiss, 2008
 * Syllis latifrons Grube, 1857
 * Syllis licheri Ravara, San Martín & Moreira, 2004
 * Syllis limbata Grube, 1880
 * Syllis longesegmentata Grube, 1857
 * Syllis lunaris (Imajima, 1966)
 * Syllis lutea (Hartmann-Schröder, 1960)
 * Syllis luteoides (Hartmann-Schröder, 1962)
 * Syllis macroceras Grube, 1857
 * Syllis macrodentata (Hartmann-Schröder, 1982)
 * Syllis magdalena Wesenberg-Lund, 1962
 * Syllis magnapalpa (Hartmann-Schröder, 1965)
 * Syllis marceloi San Martín, Álvarez-Campos & Hutchings, 2017
 * Syllis marugani Aguado, San Martín & Nishi, 2006
 * Syllis maryae San Martín, 1992
 * Syllis mauretanica (Licher, 1999)
 * Syllis mayeri Musco & Giangrande, 2005
 * Syllis mercedesae Lucas, San Martín & Parapar, 2012
 * Syllis mexicana (Rioja, 1960)
 * Syllis microoculata (Hartmann-Schröder, 1965)
 * Syllis monilaris Savigny in Lamarck, 1818
 * Syllis mytilorum Studer, 1889
 * Syllis nigra Augener, 1925
 * Syllis nigrescens Grube, 1878
 * Syllis nigricirris Grube, 1863
 * Syllis nigriscens Grube, 1878
 * Syllis nigropunctata Haswell, 1886
 * Syllis notocera Ehlers, 1905
 * Syllis nuchalis (Hartmann-Schröder, 1960)
 * Syllis obscura Grube, 1857
 * Syllis onkylochaeta Hartmann-Schröder, 1991
 * Syllis ortizi San Martín, 1992
 * Syllis parapari San Martín & López, 2000
 * Syllis parturiens Haswell, 1920
 * Syllis pectinans Haswell, 1920
 * Syllis picta (Kinberg, 1866)
 * Syllis pigmentata (Chamberlin, 1919)
 * Syllis pilosa Aguado, San Martín & Nishi, 2008
 * Syllis pontxioi San Martín & López, 2000
 * Syllis profunda Cognetti, 1955
 * Syllis prolifera Krohn, 1852
 * Syllis prolixa Ehlers, 1901
 * Syllis pseudoarmillaris Nogueira & San Martín, 2002
 * Syllis pulvinata (Langerhans, 1881)
 * Syllis quadrifasciata Fischli, 1900
 * Syllis quaternaria Moore, 1906
 * Syllis ramosa McIntosh, 1879
 * Syllis riojai (San Martín, 1990)
 * Syllis robertianae McIntosh, 1885
 * Syllis rosea (Langerhans, 1879)
 * Syllis rubicunda Aguado, San Martín & Nishi, 2008
 * Syllis rudolphi Delle Chiaje, 1841
 * Syllis schulzi (Hartmann-Schröder, 1960)
 * Syllis sclerolaema Ehlers, 1901
 * Syllis setoensis (Imajima, 1966)
 * Syllis sol San Martín, 2004
 * Syllis stenura Blanchard in Gay, 1849
 * Syllis tamarae Álvarez-Campos & Verdes, 2017
 * Syllis tiedemanni Delle Chiaje, 1841
 * Syllis torquata Marion & Bobretzky, 1875
 * Syllis tripantu Álvarez-Campos & Verdes, 2017
 * Syllis truncata Haswell, 1920
 * Syllis tyrrhena (Licher & Kuper, 1998)
 * Syllis umbricolor Grube, 1878
 * Syllis unzima Simon, San Martín & Robinson, 2014
 * Syllis valida Grube, 1857
 * Syllis variegata Grube, 1860
 * Syllis villenai Aguado, San Martín & ten Hove, 2008
 * Syllis violacea Grube, 1870
 * Syllis vittata Grube, 1840
 * Syllis vivipara Krohn, 1869
 * Syllis warrnamboolensis (Hartmann-Schröder, 1987)
 * Syllis westheidei San Martín, 1984
 * Syllis yallingupensis (Hartmann-Schröder, 1982)
 * Syllis ypsiloides Aguado, San Martín & ten Hove, 2008
 * Ramisyllis
 * Ramisyllis multicaudata Glasby, Schroeder & Aguado, 2012
 * Ramisyllis kingghidorahi M. Teresa Aguado, et al. 2022