Paradiopatra bihanica Intes & LeLoeuff 1975

Paradiopatra bihanica (Intès & LeLoeuff, 1975)

Figures 1 – 3, 11 C, D

Onuphis bihanica Intès & LeLoeuff, 1975: 314, fig. 11a–h.

Sarsonuphis bihanica.— Fauchald 1982: 68 –69, fig. 15c.

Paradiopatra bihanica. — Paxton 1986: 38; Budaeva & Fauchald 2011: 350 –353, figs 19, 20, table 5.

Paradiopatra calliopae Arvanitidis & Koukouras 1997: 53 -58, figs 1, 2, table 1 (fide Budaeva & Fauchald 2011: 350 –353); Martínez & Adarraga 2001: 143 –145, fig. 5, (Basque Country, Spain).

Onuphis lepta. — Amoureux 1970 (Tarento, Italy). Not Chamberlin, 1919.

Nothria lepta. — Amoureux 1972: 13 –14 (Galicia, Spain, Atlantic); Desbruyères et al. 1972 (Cataluña, Spain, Mediterranean); Campoy 1982: 555. Not Chamberlin, 1919.

Material examined. Three specimens (AM W.47762), COCACE station C1 (43.74°N – 05.69°W), 150 m depth, 80.04% sand, 8.28% silt, 11.68% clay, Cantabrian Sea, Bay of Biscay, 0 1 Mar 1987; 13 specimens (AM W.47763), COCACE station D2 (43.81°N – 05.75°W), 161 m depth, 90.88% sand, 3.46% silt, 5.66% clay, Cantabrian Sea, Bay of Biscay, 29 Jun 1987; 6 specimens (MNCN 16.01/16628), COCACE station D2 (43.81°N – 05.75°W), 161 m depth, 90.88% sand, 3.46% silt, 5.66% clay, Cantabrian Sea, Bay of Biscay, 29 Jun 1987; Several from the same locality for SEM studies; 4 specimens (MNCN 16.01/16629), N of San Sebastián (Basque Country), 43º 22.59’ N – 02º 03.70’ W –43º 22.16 N – 02º 05.76’ W, 104–107 m depth, Cantabrian Sea, Bay of Biscay, 24 Jun 1991, coll. Fauna Ibérica II.

Most specimens incomplete, lacking posterior ends; smallest complete specimen measuring 5 mm for 42 chaetigers, width 0.15 mm; largest specimen incomplete, measuring 10.2 mm in length for 68 chaetigers, width 0.6 mm (all larger specimens incomplete). Stored specimens cream-coloured without colour pattern.

Diagnosis. Based on specimens wider than 0.3 mm at chaetiger 10 excluding parapodia. Eyes present; palps reaching chaetiger 1, lateral antennae reaching chaetigers 4–7, median antenna equally long or slightly shorter; ceratophores with 3–5 rings, without lateral projections (Fig. 1 A). Peristomial cirri present (Fig. 1 A). Anterior three pairs of parapodia modified; ventral cirri digitiform on first three chaetigers (Fig. 1 C), ventral glandular pads with irregular cuticular pore pattern (Fig. 11 C, D); triangular postchaetal lobes on first 5–8 chaetigers (Fig. 1 B). Modified parapodia with bidentate pseudocompound hooks with moderately long pointed hoods (Fig. 1 E); from chaetiger 4 hooks replaced by limbate chaetae, upper bundle long, lower one shorter and cultriform to spine-like; lower limbate chaetae replaced from chaetiger 9 by subacicular hooks (Fig. 1 G) and pectinate chaetae with slightly oblique combs with 15–20 teeth (Fig. 1 F), rarely as few as 10–14 (Fig. 3 D). Branchiae pectinate, starting as single filaments from chaetigers 10–14, with up to three filaments (Fig. 1 D); absent from chaetiger 35–40. Tubes cylindrical with inner parchment-like layer and outer layer of mud particles, sometimes with some shell fragments incorporated.

Variation. Some variation was noted in the specimens examined (Fig. 2). Most of it is size-related, as is the maximal number of ceratophoral rings of antennae (Fig. 2 A), the number of teeth of pectinate chaetae (Fig. 2 B) and the presence of pseudocompound cultriform limbate chaetae in the ventral fascicle of anterior chaetigers. The smallest specimens (0.15–0.2 mm width at chaetiger 10, Fig. 3 A) had pectinate chaetae with 8–14 teeth (Fig. 3 D), from there the number of teeth increased with animal size, reaching 15–20 teeth in specimens of the largest sizes (0.5–0.6 mm width). In both cases, pectinate chaetae of anteriormost chaetigers have less number of teeth than posterior ones. The lowermost chaetae of the ventral fascicle from chaetiger 4–8 were spine-like and pseudocompound cultriform limbates (Fig. 3 B, C) in the smallest specimens (0.15–0.3 mm in width) and were progressively replaced by simple cultriform limbates in specimens larger than 0.3 mm in width. This together with the possession of pectinate chaetae with fewer teeth represents a juvenile phase in the attainment of the adult chaetal complement. In view of these observed juvenile characteristics we have restricted the diagnosis of P. bihanica to specimens with a width of more than 0.3 mm at chaetiger 10. In all examined specimens larger than 0.15 mm (width of 10th chaetiger) the subacicular hooks appeared invariably on chaetiger 9 (Fig. 2 C). Similarly, the chaetiger of branchial appearance ranged from 10 to 14 and does not seem to be size-related (Fig. 2 D).

Remarks. The holotype of P. bihanica and newly collected material from the type locality was examined by Budaeva & Fauchald (2011). They evaluated the main diagnostic characters and demonstrated that all ranges of variability of P. bihanica and P. calliopae (Arvanitidis & Koukouras, 1997) overlapped, and considered the latter as a junior synonym of the former.

The original description of P. bihanica stated that the median antenna reached to chaetigers 15–20 with the lateral antennae being slightly shorter, as was also illustrated (Intès & LeLoeuff 1975: fig. 11a). Budaeva & Fauchald (2011) examined the holotype and found that all antennae were equally long, reaching to chaetiger 7. They also examined newly collected material from the type locality and concluded that the median antenna was equal in length or shorter than the lateral antennae with the median reaching to chaetigers 3–6 and the laterals to chaetigers 4–7, which agrees with our material examined.

Overall, our material agrees closely with the description given by Budaeva & Fauchald (2011). However, the range of variation of some characters in Iberian specimens, i.e. the number of ceratophoral rings on antennae and the number of teeth of pectinate chaetae was wider than that indicated for the species by Budaeva & Fauchald (2011). The new variation ranges found are consistent with those given by Martínez & Adarraga (2001) for the Basque Country population (northern Spain).

Nothria lepta (Chamberlin, 1919) or its original designation Onuphis lepta have been repeatedly reported from the Iberian Peninsula (Amoureux 1972, Desbruyères et al. 1972, Campoy 1982). However, these records were questioned (Fauchald 1982, Glémarec 1991, Arvanitidis & Koukouras 1997, Martínez & Adarraga 2001). The last two authors have considered these records as misidentifications of P. calliopae (now accepted as P. bihanica) and N. lepta (now accepted as Paradiopatra lepta) is considered a species restricted to the East Pacific Ocean (Budaeva & Fauchald 2011). We agree with these statements and are adding the records of N. lepta by Amoureux (1972), Desbruyères et al. (1972) and Campoy (1982) into the list of subjective synonyms of the species. Nevertheless, we recommend caution since not all Iberian or European records of N. lepta may correspond to P. bihanica. Some records, e.g. Amoureux (1974) are most likely to correspond to Nothria maremontana André & Pleijel, 1989 (see Paxton & Arias 2014) or Alós (1984) that actually were referred to an Aponuphis sp. (see Arvanitidis & Koukouras 1997).

Distribution. East Atlantic, from the Bay of Biscay to the Gulf of Guinea, including the western and central Mediterranean Sea.