Onuphis rullieriana ( Amoureux, 1977 )

Arias, Andrés & Paxton, Hannelore, 2015, Onuphis and Aponuphis (Annelida: Onuphidae) from southwestern Europe, with the description of a new species, Zootaxa 3949 (3), pp. 345-369 : 356-357

Onuphis rullieriana ( Amoureux, 1977)

Figure 6

Nothria rullieriana Amoureux, 1977: 399 –402, fig. 1.

Onuphis rullieriana . — Fauchald, 1982: 51 –53, fig. f–g, table 17; Aguirrezabalaga et al. 2002: 27 (Capbreton Canyon, Bay of Biscay).

Type locality. Entrance of the English Channel, 860–1400 m depth, East Atlantic.

Material examined. Non-type material. One specimen (AM W27379) Capbreton Canyon, Bay of Biscay, 979–990 m depth, 7 Jul 1988; 4 specimens ( MNCN 16.01/15245) N. Prieto Cape, Asturias (43º 49.10’ N, 4º 52.74’ W –43º 49.33 N, 4º 53.47’ W), Cantabrian Sea, Bay of Biscay, 925–1025 m depth, 25 Jun 1991; 2 specimens (AM W.47514) N. Prieto Cape, Asturias (43º 49.10’ N, 4º 52.74’ W –43º 49.33 N, 4º 53.47’ W), Cantabrian Sea, Bay of Biscay, 925–1025 m depth, 25 Jun 1991; 3 specimens coated with gold ( MNCN 16.01/15246) N. Prieto Cape, Asturias (43º 49.10’ N, 4º 52.74’ W –43º 49.33 N, 4º 53.47’ W), Cantabrian Sea, Bay of Biscay, 925–1025 m depth, 25 Jun 1991; 2 specimens ( MNCN 16.01/16161) COCACE station: I2 (43.99º N, 5.83º W), N. Spain, Cantabrian Sea, Bay of Biscay, 1025 m, 58.44 % sand, 17.56 % silt, 24.00 % clay, 2 Jul 1987.

Diagnosis. Prostomium anteriorly extended. Eye spots absent. Palps reaching chaetiger 1–2, lateral antennae reaching chaetiger 5–16 and median antenna chaetiger 3–14. Ceratophores with nine to 10 rings in palps, 10–13 in lateral antennae and eight to ten rings in median antenna. Subulate ventral cirri in first five to six chaetigers; subulate postchaetal lobes distinct in first 12 chaetigers. Tridentate pseudocompound hooks with triangular pointed hoods present in first four chaetigers. All hooks of equal thickness, slender long-appendaged ones absent. Pectinate chaeta from chaetiger 5 with 13–15 teeth. Subacicular hooks present from chaetiger 14. Simple strap-like branchiae present from chaetiger 1 and continuing throughout.

Remarks. Examined specimens ranged in width between 1.4 to 2.5 mm. Almost complete specimens over 61 mm in length with 78 chaetigers. Some preserved specimens presented a colour pattern consisting of a brown bar on the prostomium, brown spots at the base of ceratophores and styles of antennae and palps and brown spots at the base of dorsal cirri, postchaetal lobes and parapodial bases of anterior chaetigers; other specimens were cream coloured without pigmentation. The pseudocompound hooks of the anterior modified chaetigers of O. rulleriana have relatively long and triangular hoods with pointed tips ( Figs 6 A–D). These long hoods are uncharacteristic for the genus Onuphis , which usually has short falcate-hooded hooks. The hooks have three stout and blunted teeth, with the intermediate tooth bigger than the others ( Figs 6 C, D). The appendages of all hooks are almost equally long; however the hooks from the middle of fascicle are slightly thicker than the others and weakly tridentate ( Fig. 6 D). Pectinate chaetae occur from chaetiger 5, with 13–15 teeth and are slightly curved on the margins, usually two per parapodium ( Fig. 6 E).

Fauchald (1982), in his revision based upon type material, pointed out that within five paratypes of O. rulleriana examined by him, four had branchiae first present from chaetiger 1 but in the remaining one the appearance of a single branchial filament occurred at chaetiger 3. Thus, he concluded that the appearance of branchiae ranges from chaetiger 1 to 3 in this species. We have examined 15 specimens and all have branchiae starting from chaetiger 1 so we consider that the specimen with branchiae starting from chaetiger 3 most likely represents an abnormal individual. Therefore, we maintain within the species diagnosis the presence of branchiae from chaetiger 1, according to the original description and following Aguirrezabalaga et al. (2002).

Distribution. East Atlantic off Britain and the Bay of Biscay (925–1025 m deep). The species was reported from Wasaka Bay ( Japan) on the basis of two specimens collected from 150–257 m depth ( Maekawa & Hayashi 1989). However after a decade, the same authors in a subsequent paper reconsidered their initial identification and transferred the identity of this species to Onuphis sp. ( Maekawa & Hayashi 1999).

Figures

FIGURE 6. Onuphis rullieriana. Scanning electron micrographs. A, tridentate pseudocompound hook from the lower fascicle of chaetiger 1; B, tridentate pseudocompound hook from the middle of fascicle of chaetiger 1; C, detailed view of tip of pseudocompound hook from the lower fascicle of chaetiger 2; D, detailed view of tip of weakly tridentate pseudocompound hook from the middle fascicle of chaetiger 2; E, pectinate chaetae from chaetiger 6.