Orbiniella Day, 1954

Blake, James A., 2020, New species and records of deep-water Orbiniidae (Annelida, Polychaeta) from the Eastern Pacific continental slope, abyssal Pacific Ocean, and the South China Sea, Zootaxa 4730 (1), pp. 1-61 : 38

Genus Orbiniella Day, 1954

Type-species: Orbiniella minuta Day, 1954 , by monotypy.

Synonym: Falklandiella Hartman, 1967 . Fide Buzhinskaja 1992: 76. Type species: Falklandiella annulata Hartman, 1967 , by monotypy.

Diagnosis: (after Blake 2017) Body elongate, with separation between thorax and abdomen indistinct, anterior segments may be shorter than more posterior segments, but size changing gradually over several segments, or no change in appearance between anterior and posterior segments; prostomium broad or elongate with paired nuchal organs usually present, these sometimes pigmented, eyespots present or absent; peristomium with 1–2 asetigerous rings. Noto- and neuropodia poorly developed, consisting of low tori from which setae emerge; with only simple post-setal lamellae, or these entirely absent; posterior parapodia not elevated and shifted dorsally as in genera of the Orbiniinae . Capillary noto- and neurosetae always crenulated or weakly camerated with pointed bristles apparent at relatively low magnification (100x); prominent acicular spines present or absent in noto- and neuropodia, or entirely absent; furcate setae absent. Branchiae absent.

Remarks. According to Blake (2017), there are 13 valid species of Orbiniella . Of these, only four are reported from deep-water habitats exceeding 1500 m. Six new deep-water species of Orbiniella have been discovered in the present study: O. abyssalis n. sp. from the abyssal Pacific Ocean at the Clarion-Clipperton Fracture Zone, O. grasslei n. sp. from hydrothermal vents on the East Pacific Rise at 21°N, O. tumida n. sp. from the continental slope off California, and three species, O. eugeneruffi n. sp., O. longilobata n. sp., and O. rugosa n. sp. from the South China Sea off Brunei. These new taxa bring the total number of known species of Orbiniella to 19, ten of which occur in deep-water.