Paradiopatra bihanica, (INTES & LE LOEUFF, 1975)

Budaeva, Nataliya & Fauchald, Kristian, 2011, Phylogeny of the Diopatra generic complex with a revision of Paradiopatra Ehlres, 1887 (Polychaeta: Onuphidae), Zoological Journal of the Linnean Society 163 (2), pp. 319-436 : 350-353

PARADIOPATRA BIHANICA ( INTES & LE LOEUFF, 1975) ( FIGS 19 AND 20; TABLE 5)

Onuphis bihanica Intes & Le Loeuff, 1975: 314 , fig. 11a–h.

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

Paradiopatra bihanica Paxton, 1986a: 38 .

Paradiopatra calliopae Arvanitidis & Koukouras,

1997: 53–58, figures 1 and 2, table 1.

Type material: Paradioatra bihanica: MNHN POLY TYPE 1246 , ORSTOM Expedition , off Côte d’Ivoire, 5.055°N, 4.083°W, 200 m, 23 November 1966, dredge, coll. Intes, A. & Le Loeuff, P. (holotype).

P. calliopae: MNHN POLY-TYPE 0354, Mediterranean Sea , off Mount Athos coast, 40.34°N, 24.168°E, 70–80 m, 10 June 1990, Agassiz trawl (one paratype); MNHN POLY-TYPE 1241 , the same locality (one paratype) .

Non-type material examined: ZMUB, Fridtjof Nansen St. N 2D (one); St. N4D (16); St. N7D (eight); St. N10D (one).

Type locality: Atlantic Ocean , West Africa, off Côte d’Ivoire, 5.055°N, 4.083°W, 200 m.

Diagnosis: First three pairs of parapodia with pseudocompound bidentate falcigers with moderately long pointed hoods; ventral cirri subulate on first three chaetigers; subacicular hooks starting from chaetiger 9; branchiae pectinate, with up to three filaments, starting from chaetigers 9–13; peristomial cirri present.

Description: Holotype, an incomplete specimen, about 4.5 mm long and 0.42 mm wide, with 31 chaetigers. Width of non-type specimens varying from 0.3 to 0.6 mm. All specimens light brownish, lacking colour pattern.

Prostomium rounded with paired ovoid frontal lips ( Fig. 19B ). Palps reaching chaetiger 1; lateral antennae reaching chaetiger 7 (chaetigers 3–7); median antenna almost as long as lateral ones, reaching chaetiger 7 (chaetiger 3–7) ( Fig. 19A, B ). Ceratophores of lateral antennae consisting of three or four rings, without lateral projections ( Fig. 19A ). Eyes present, located near bases of lateral antennae. Nuchal grooves almost straight, covered by the anterior fold of peristomium. Peristomium as long as first chaetiger. Peristomial cirri present, slightly shorter than peristomium ( Fig. 19A ).

Anterior three pairs of parapodia modified, projecting lateroventrally, directing slightly anteriorly. Prechaetal lobes short and rounded; postchaetal lobes well developed on first 5–8 chaetigers (usually indistinct because of the poor condition of the material examined). Dorsal cirri subulate on all chaetigers. Ventral cirri subulate on first three chaetigers ( Fig. 19B, E, F ), later replaced by elongated transverse oval glandular pads ( Fig. 19B, G–I ).

First three pairs of parapodia with one dorsal simple capillary chaeta and ventral fascicle of three or four pseudocompound falcigers ( Fig. 19E, F ). All falcigers bidentate with moderately long pointed hoods ( Fig. 19C ). Two fascicles of limbate chaetae starting from chaetiger 4 ( Fig. 19G ). Ventral fascicle of limbate chaetae replaced by paired simple bidentate subacicular hooks from chaetiger 9 ( Fig. 19D, H ). Pectinate chaetae thin and delicate, with 12–15 small teeth and slightly oblique distal margin. Neuroaciculae with pointed tips, one or two per parapodium.

Branchiae single or pectinate, starting from chaetiger 9 (chaetigers 10–13), and continuing to chaetigers 39–40 ( Fig. 19H, I ). Holotype with two branchial filaments on the best-developed branchiae. Non-type specimens with between one and three filaments. Maxillary formula of one paratype according to Intes & Le Loeuff (1975): Mx I = 1 + 1; Mx II = 8 + 8; Mx III = 6 + 0; Mx IV = 3 + 3; Mx V = 1 + 1.

Tubes absent in type material studied. Non-type specimens with long cylindrical tubes consisting of inner parchment-like layer and very thick (two or three times thicker than internal tube diameter) outer layer of mud particles. Pygidium with terminal anus and two pairs of anal cirri ( Arvanitidis & Koukouras, 1997).

Remarks: Onuphis bihanica was originally described from the west coast of Africa ( Côte d’Ivoire), and is particularly characterized by the relatively late beginning of branchiae. The original figure of the anterior part of the body shows the relatively long median antenna, comparable in length with the lateral antennae ( Intes & Le Loeuff, 1975). Fauchald (1982) re-examined one of the paratypes and referred this species to Sarsonuphis based on the presence of long hoods on anterior falcigers. He reported that antennae of the paratype are equal in length and reach chaetiger 7. Paxton (1986a) referred O. bihanica to Paradiopatra , indicating that this species may be invalid, and represent juveniles of O. amoureuxi .

Arvanitidis & Koukouras (1997) described P. calliopae from the Mediterranean Sea as closely resembling P. bihanica . The major differences between these two species were the relative length of the median antenna, number of branchial filaments, number of chaetigers with digitiform postchaetal lobes, and number of teeth in maxillae ( Arvanitidis & Koukouras, 1997). These authors had examined the holotype of P. bihanica and found it to be dried out with broken distal tips of all antennae. Thus all measurements of the length of antennae in the holotype were considered to be unreliable, and comparison between P. calliopae and P. bihanica has been made based on the original description and illustrations.

We re-examined the holotype of P. bihanica and found it to be in relatively good condition. All antennae were of the same length (reaching chaetiger 7). Newly collected material from the type locality allowed an evaluation of the variability of the main diagnostic characters in P. bihanica . Here we re-describe P. bihanica as having the median antenna equal in length or shorter than the lateral antennae. Moreover, analysis of non-type specimens showed that all ranges of variability of diagnostic characters overlap in P. bihanica and P. calliopae ( Table 5). Consequently, we consider P. calliopae as a junior synonym of P. bihanica .

Paradiopatra bihanica resembles P. pyricirra sp. nov. in having three pairs of modified parapodia bearing bidentate pseudocompound hooks with moderately long hoods and subacicular hooks starting from chaetiger 9. Ranges of chaetiger number of the origin of branchiae also overlap in these two species. However, P. bihanica differs from P. pyricirra sp. nov. by the relative length of the median antenna, which is almost as long as the lateral antennae in P. bihanica , and is significantly shorter in P. pyricirra sp. nov. Paradiopatra bihanica can also be distinguished from P. pyricirra sp. nov. by having rather than lacking eyes, by having three or four, rather than between five and seven, rings on lateral ceratophores, by tubes with an extremely thick outer muddy layer, and by elongate transverse rather than almost rounded ventral glandular pads. Paradiopatra bihanica is one of the smallest members of Paradiopatra , reaching a maximum of 0.6 mm in width, whereas P. pyrricirra normally grows to a width of 1.3–2 mm. Paradiopatra bihanica differs from other small species of Paradiopatra , such as P. fragosa , P. hispanica , and P. okai , by having rather than lacking branchiae.

Distribution: Eastern Atlantic, West Africa, off Côte d’Ivoire, off Nigeria; Mediterranean Sea ( Fig. 20). Depth range 70– 300 m.

Figures

Figure 19. Paradiopatra bihanica (MNHN POLY TYPE 1246, A, B; ZMUB, Fridtjof Nansen St. N4D, C–I): A, anterior end, dorsal view; B, anterior end, ventral view; C, bidentate pseudocompound falciger from chaetiger 1; D, subacicular hook from chaetiger 9; E, parapodium of chaetiger 2, anterior view; F, parapodium of chaetiger 3, anterior view; G, parapodium of chaetiger 4, anterior view; H, parapodium of chaetiger 9, anterior view; I, parapodium of chaetiger 19, anterior view.