Ophryotrocha is a genus of marine polychaete worms in the family Dorvilleidae.
Ophryotrocha comprises a multitude of extant species of polychaete worms with more thought to exist in both shallow and deep waters. Polychaetes of this genus thrive in nutrient-rich environments and can often be found in polluted marine areas that are often sites of human activity.Ophryotrocha'''s durability allows them to exist in a myriad of stressful environments. Found in the oceans surrounding Europe, Asia, the Mediterranean, and beyond, they can survive in low-oxygen environments and are known to be sulfide tolerant, allowing this genus to live in areas most species cannot. Most worms are between 1 and 5 mm in length, but some deep sea species have been documented to be much larger, ranging from 10 and 25mm. Ophryotrocha is often used as a scientific test species due to their high fecundity, stress tolerance, and myriad of sexual systems found within the genus.
All polychaetes of this genus are laid in batches of roughly 100 eggs and the majority of species start out in a free-moving larval stage as protandrous hermaphrodites. During the protandrist stage of adolescence, small males will start producing sperm when the body length is still small but will continue to stay male if females are present in an effort to avoid the energetic costs of producing oocytes. As this genus continues to grow they develop into tube-building sessile adults. Although no study has documented their entire life process, all Ophryotrocha are documented to breed and die after the dispersal of offspring with parental care given to eggs by one or both sexes resting on the egg cocoon. Parental care is thought to act as a mode for cleaning the cocoon and is documented in all studied species within the genus.
Species The World Register of Marine Species lists the following species in the genus:Ophryotrocha adherens Paavo, Bailey-Brock & Akesson, 2000Ophryotrocha akessoni Blake, 1985Ophryotrocha alborana Paxton & Åkesson, 2011Ophryotrocha antarctica Szaniawski & Wrona, 1987Ophryotrocha atlantica Hilbig & Blake, 1991Ophryotrocha baccii Parenti, 1961Ophryotrocha batillus Wiklund et al., 2012Ophryotrocha bifida Hilbig & Blake, 1991Ophryotrocha birgittae Paxton & Åkesson, 2011Ophryotrocha cantabrica Núñez, Riera & Maggio, 2014Ophryotrocha claparedei Studer, 1878Ophryotrocha clava Taboada, Wiklund, Glover, Dahlgren, Cristobo & Avila, 2013Ophryotrocha cosmetandra Oug, 1990Ophryotrocha costlowi Paxton & Åkesson, 2010Ophryotrocha craigsmithi Wiklund, Glover & Dahlgren, 2009Ophryotrocha cyclops Salvo, Wiklund, Dufour, Hamoutene, Pohle & Worsaae, 2014Ophryotrocha diadema Åkesson, 1976Ophryotrocha dimorphica Zavarzina & Tsetlin, 1986Ophryotrocha dubia Hartmann-Schröder, 1974Ophryotrocha eutrophila Wiklund, Glover & Dahlgren, 2009Ophryotrocha fabriae Paxton & Morineaux, 2009Ophryotrocha flabella Wiklund et al., 2012Ophryotrocha gerlachi Hartmann-Schröder, 1974Ophryotrocha geryonicola (Esmark, 1878)Ophryotrocha globopalpata Blake & Hilbig, 1990Ophryotrocha gracilis Huth, 1933Ophryotrocha hadalis Jumars, 1974Ophryotrocha hartmanni Huth, 1933Ophryotrocha irinae Tsetlin, 1980Ophryotrocha japonica Paxton & Åkesson, 2010Ophryotrocha jiaolongi Zhang, Zhou, Wang & Rouse, 2017Ophryotrocha kagoshimaensis Miura, 1997Ophryotrocha labidion Hilbig & Blake, 1991Ophryotrocha labronica Bacci & La Greca, 1961Ophryotrocha langstrumpae Wiklund et al., 2012Ophryotrocha lipovskyae (Paxton, 2009)Ophryotrocha lipscombae Lu & Fauchald, 2000Ophryotrocha littoralis (Levinsen, 1879)Ophryotrocha lobifera Oug, 1978Ophryotrocha longicollaris Wiklund et al., 2012Ophryotrocha longidentata Josefson, 1975Ophryotrocha lukowensis Szaniawski, 1974Ophryotrocha lusa Ravara, Marçal, Wiklund & Hilário, 2015Ophryotrocha maciolekae Hilbig & Blake, 1991Ophryotrocha macrovifera Paxton & Åkesson, 2010Ophryotrocha maculata Åkesson, 1973Ophryotrocha magnadentata Wiklund et al., 2012Ophryotrocha mammillata Ravara, Marçal, Wiklund & Hilário, 2015Ophryotrocha mandibulata Hilbig & Blake, 1991Ophryotrocha mediterranea Martin, Abello & Cartes, 1991Ophryotrocha minuta Levi, 1954Ophryotrocha natans Pfannenstiel, 1975Ophryotrocha nauarchus Wiklund et al., 2012Ophryotrocha notialis (Ehlers, 1908)Ophryotrocha notoglandulata Pfannenstiel, 1972Ophryotrocha obtusa Hilbig & Blake, 1991Ophryotrocha orensanzi Taboada, Wiklund, Glover, Dahlgren, Cristobo & Avila, 2013Ophryotrocha pachysoma Hilbig & Blake, 1991Ophryotrocha paragerlachi Brito & Nunez, 2003Ophryotrocha paralabidion Hilbig & Blake, 1991Ophryotrocha permanae Paxton & Åkesson, 2010Ophryotrocha platykephale Blake, 1985Ophryotrocha puerilis Claparède & Mecznikow, 1869Ophryotrocha robusta Paxton & Åkesson, 2010Ophryotrocha rubra Paxton & Åkesson, 2010Ophryotrocha sadina Ravara, Marçal, Wiklund & Hilário, 2015Ophryotrocha scarlatoi Averincev, 1989Ophryotrocha schubravyi Tsetlin, 1980Ophryotrocha scutellus Wiklund, Glover & Dahlgren, 2009Ophryotrocha shieldsi Paxton & Davey, 2010Ophryotrocha socialis Ockelmann & Akesson, 1990Ophryotrocha spatula Fournier & Conlan, 1994Ophryotrocha splendida Brito & Nunez, 2003Ophryotrocha vellae Paxton & Åkesson, 2010Ophryotrocha vivipara Banse, 1963Ophryotrocha wubaolingi Miura, 1997
Sexual systems The many species of polychaete worms within the genus Ophryotrocha exhibit a variety of sexual systems. Distinct species demonstrate different systems, with simultaneous hermaphroditism, gonochorism, and sequential hermaphroditism all documented. The ancestral state of this genus of worms is known to be simultaneous hermaphroditism. Generally, the simultaneous hermaphroditic species are protandrous as adolescents and mate in pairs. The formation of pairs is decided by a long courtship process where partners are linked together in a pseudocopulation. In simultaneous hermaphrodites, each adult has a pair of gonads that produce gametes which are emitted into the water column where external fertilization occurs. After courtship, both simultaneous hermaphroditic individuals repeat the process of egg-laying and fertilizing (known as egg trading to avoid sexual conflict between the two simultaneous hermaphrodites. As with many hermaphroditic species, Ophryotrocha'' polychaetes are thought to have evolved simultaneous hermaphroditism as an ancestral state because of lack of mate access to allow sexually viable individuals to produce offspring without sex barriers blocking reproduction opportunities as this genus cannot self-fertilize.
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