Gymnonereis Horst, 1919

Darbyshire, Teresa, 2014, Intertidal and nearshore Nereididae (Annelida) of the Falkland Islands, southwestern Atlantic, including a new species of Gymnonereis, ZooKeys 427, pp. 75-108 : 77

Taxon classification Animalia Phyllodocida Nereididae

Genus Gymnonereis Horst, 1919

Gymnorhynchus Horst, 1918: 247. - Pre-occupied by Gymnorhynchus Rudolphi, 1819; Cestoda (paper cited from Pettibone 1970).

Gymnonereis Horst, 1919: 64. - Pettibone 1970: 234. - Banse 1977: 621-622 (in part).

Type species.

Gymnonereis sibogae (Horst, 1918) by monotypy

Diagnosis

(after Hutchings and Reid 1990). Body elongate, depressed, attenuated posteriorly. Prostomium with frontal margin deeply incised between bases of frontal antennae.

Eversible pharynx with jaws having cutting edge smooth or serrated, with papillae on the oral ring. Notopodia with accessory dorsal cirri attached to dorsal cirrophores in anterior region only, with prechaetal lobes and short, rounded postchaetal lobes. Median segments with dorsal cirrophores greatly elongated and highly vascularized (except in Gymnonereis crosslandi ) and lacking accessory cirri. Dorsal transverse ridges present or absent. Chaetae homogomph or sesquigomph spinigers and homogomph or sesquigomph falcigers may be present. Chaetae very numerous in anterior chaetigers.

Remarks.

Hutchings and Reid (1990) used the term 'sesquigomph', in a review of Australian Gymnonereidinae , to describe those chaetae that have a 3:2 ratio between the boss and opposing prong of the shaft. Such chaetae were referred to as 'slightly hemigomph' by Fauchald (1977) or 'slightly heterogomph' by Hylleberg and Nateewathana (1988) in their descriptions of Gymnonereis . Terminology referring to the additional dorsal (=accessory dorsal) cirrus and ventral (=double ventral) cirri follow that of both Hutchings and Reid (1990) and Santos et al. (2005) in the first instance but only Santos et al. (2005) in the second. Finally, the parapodial projections referred to as 'prechaetal ligules’ in both Hylleberg and Nateewathana (1988) and Hutchings and Reid (1990) are here termed prechaetal lobes, after Santos et al. (2005), who defined notopodial projections supported by aciculae as lobes and those without aciculae as ligules and found notopodial ligulae to be absent in Gymnonereis . This definition has also been applied here to the previously-termed 'neuropodial prechaetal ligules’, referred to here as neuropodial prechaetal lobes (Fig. 1).