Paradiopatra florencioi, Arias, Andrés & Paxton, Hannelore, 2015

Arias, Andrés & Paxton, Hannelore, 2015, Paradiopatra Ehlers, 1887 (Annelida: Onuphidae) from southwestern Europe with the description of a new species and new ultramorphological data for the genus, Zootaxa 4040 (2), pp. 149-168 : 156-162

Paradiopatra florencioi sp. nov.

Figures 5–8 , 11 E, F

Onuphis quadricuspis .– Amoureux, 1974a: 136 ( Portugal); Amoureux, 1973: 114 (Bay of Biscay); Campoy 1982: 560 –561. Not M. Sars, 1872.

Paradiopatra quadricuspis .— Aguirrezabalaga et al. 2002: 23, fig. 3A–H (Bay of Biscay). Not M. Sars, 1872.

Material examined. Type material: Holotype ( MNCN 16.01/16619), COCACE station G3 (43.88º N – 06.11º W), 571 m depth, 41 % sand, 30% silt, 29 % clay, Cantabrian Sea, Bay of Biscay, 0 3 Jul 1987. Three paratypes ( MNCN 16.01/16620, MNCN 16.01/16621, MNCN 16.01/16622), same station data as holotype; 4 paratypes: 2 ethanol preserved (AM W.47764), 2 coated with gold (AM W.47765/stub MI1184; AM W.47766/stubs MI1185/ 86), same station data as holotype; 3 paratypes ( MNCN 16.01/16623, MNCN 16.01/16624, MNCN 16.01/16625) COCACE station I6 (43.92°N – 06.11°W), 1186 m depth, 38% sand, 30% silt, 32% clay, Cantabrian Sea, Bay of Biscay, 0 4 Jul 1987; 2 paratypes ( ANEA 2015.900-901), COCACE station I6 (43.92°N – 06.11°W), 1186 m depth, 38% sand, 30% silt, 32% clay, Cantabrian Sea, Bay of Biscay, 0 4 Jul 1987; 1 paratype ( MNHN TYPE 1569), COCACE station I6 (43.92°N – 06.11°W), 1186 m depth, 38% sand, 30% silt, 32% clay, Cantabrian Sea, Bay of Biscay, 0 4 Jul 1987.

Non-type material. One specimen (AM W.47767), COCACE station I6 (43. 92º N– 06.11º W), 1186 m depth, 38 % sand, 30% silt, 32 % clay, Cantabrian Sea, Bay of Biscay, 0 4 Jul 1987; 1 specimen (AM W.27377), Capbreton Canyon (43º38.45’N – 02º18.02’W), 1063 m depth, Cantabrian Sea, Bay of Biscay, 0 6 Jul 1988; 2 specimens (AM W.27378), Capbreton Canyon (43º43.87’N – 02º19.16’W), 936 m depth, Cantabrian Sea, Bay of Biscay, 0 8 Jul 1988.

Comparative material. Paradiopatra quadricuspis: Five paralectotypes ( ZMO C3172) Drøbak, Oslofjord, Norway; 8 specimens (AM W.198970) southwest Norway; 2 specimens ( BMNH ZK 1921.5.1.1827) Bergen, Norway.

Type locality. NW Atlantic, Bay of Biscay, Cantabrian Shelf, 43.88º N – 06.11 ºW, 571 m depth.

Diagnosis. Eyes absent; palps reaching chaetiger 1, lateral antennae reaching chaetiger 3–7, median antenna reaching chaetiger 1–2; ceratophores with 5–7 rings, lateral projections absent. Peristomial cirri present. Anterior three pairs of parapodia modified; ventral cirri subulate on first two chaetigers, third transitional, ventral glandular pads with irregular cuticular pore pattern; triangular to subulate postchaetal lobes on first eight chaetigers. Modified parapodia with bi- and tridentate pseudocompound hooks with long pointed hoods; subacicular hooks starting from chaetiger 9, pectinate chaetae of two types: i) flat with slightly oblique comb with 19–26 teeth, two per parapodium; ii) slightly scoop-shaped with rolled lateral margins, long appendaged, with 19–21 teeth, present only in median chaetigers, always single. Branchiae pectinate, starting as single filaments from chaetiger 6–7, reaching maximum of three to four filaments.

Description. Description based on holotype, with variation of paratypes included. All type specimens lacking posterior ends. Length of holotype 31 mm for 76 chaetigers, width 0.5 mm (at chaetiger 10, excluding parapodia); paratypes ranging from 7–21 mm long (19–47 chaetigers), 0.7–1.0 mm wide. Alcohol stored specimens overall cream-coloured, lacking colour pattern. Prostomium short, half as long as wide, with paired, closely spaced ovoid frontal lips, directed anteroventrally ( Fig. 5 A, C).

Ceratostyles slender and tapering; palps reaching chaetiger 1; lateral antennae reaching chaetiger 3–5 (to 7 in paratypes); median antenna reaching chaetiger 1–2. Ceratophores with well ( Fig. 5 C) to weakly developed annulation ( Fig. 5 E), lacking lateral projections ( Fig. 5 C); ceratophores of lateral antennae with four to six rings, median antenna with four to five rings; distal ring as long as all basals together. Nuchal grooves with wide middorsal separation, laterally curved towards lateral antennae. Eyes absent. Peristomium as long as first chaetiger. Peristomial cirri short and tapering, about half as long as peristomium, inserted subdistally ( Fig. 5 A, C).

First three pairs of parapodia modified, projecting anterolaterally, directed slightly ventrally ( Fig. 5 A, B, E). Prechaetal lobes rounded on all parapodia; postchaetal lobes triangular to subulate in first eight chaetigers ( Fig. 5 A, B), decreasing rapidly in size thereafter. Dorsal cirri well developed and subulate in anterior parapodia, becoming smaller and cirriform in median region. Ventral cirri subulate on first two chaetigers, on third one shorter with blunt end and replaced by ovoid ventral glandular pads from chaetiger 4 ( Fig. 5 B), cuticular pore pattern irregular ( Fig. 11 E, F).

Parapodia usually supported by four aciculae (3–5) with pointed tips, projecting less than half as far as pseudocompound hooks and limbate chaetae from prechaetal lobes ( Figs 6 A). First three pairs of parapodia with dorsal fascicle of 1–2 simple limbate chaetae and ventral fascicle of 4–5 bi- and tridentate pseudocompound hooks with long pointed hoods ( Figs 6 A–D, 7A); shafts of pseudocompound hooks and appendages with scattered spines ( Fig.7 C). Two fascicles of simple limbate chaetae starting from chaetiger 4. Ventral fascicle of limbate chaetae replaced by paired bidentate subacicular hooks from chaetiger 9, hooks unequal, upper one thicker and longer than lower one ( Fig. 7 E, F). Pectinate chaetae of two types: i) flat with wide shafts, combs slightly oblique with 19–21 teeth in anterior chaetigers, from chaetiger 9–10 ( Fig. 7 D) and with 22–26 teeth in median and posterior ones ( Fig. 7 H), two per parapodium; ii) slightly scoop-shaped with rolled lateral margins, long appendaged, with 19–21 teeth, present only in median chaetigers, always single ( Fig. 7 G).

Branchiae present from chaetiger 6–7 as simple filament ( Fig. 5 E), attaining maximum of three to four filaments in median body region and continuing to chaetiger 45–51 ( Fig. 7 B). Posterior end unknown. Tube cylindrical with inner thin parchment-like layer and outer thicker layer of mud particles ( Fig.5 D). Mandibles ( Fig. 6 F) thin and delicate, protomandibles prominently visible. Maxillae delicate, lightly sclerotised ( Fig. 6 E); maxillary formula: Mx I = 1 + 1; Mx II = 8 + 9; Mx III = 7 + 0; Mx IV = 5 + 9; Mx V = 1 + 1.

Variation. Paradiopatra florencioi sp. nov. does not display a high degree of variability with respect to its prostomial appendages, parapodial structures and chaetae. Most variation is size-related, as the maximal number of branchial filaments ( Fig. 8 A). The number of anterior chaetigers with subulate ventral cirri was two in most of the examined specimens, however in the largest specimens (width of 10th chaetiger of 1.1 mm) the intermediate-shaped ventral cirrus from chaetiger 3 becomes subulate. As discussed above, the first appearance of subacicular hooks is usually not size-dependent in species of Paradiopatra . In all examined specimens of P. florencioi larger than 0.3 mm (width of 10th chaetiger) the appearance of subacicular hooks occurred invariably on chaetiger 9 ( Fig. 8 B).

Remarks. The new species is very similar to P. quadricuspis . The two species differ mainly in that the former has bi- and tridentate pseudocompound hooks in the anterior modified parapodia while in the latter they are only bidentate. Budaeva & Fauchald (2011) examined a large amount of P. quadricuspis material from the type locality and the Norwegian and Greenland seas and found that they demonstrated a complete lack of variability in the dentition of pseudocompound hooks. Another difference between the two species is that P. quadricuspis presents only one type of pectinate chaeta, flat with slightly oblique distal margin (the regular flat one) while P. florencioi sp. nov. possesses two types, the usual flat chaeta, two per parapodium ( Fig. 7 D, H) and another slightly scoopshaped one with rolled lateral margins, always single ( Fig. 7 G). Furthermore, the peristomial cirri of the new species are only half as long as the peristomium whilst in P. quadricuspis they are almost equal in length with the peristomium.

Budaeva & Fauchald (2011) considered Paradiopatra quadriscupis as limited to northern Europe ( Norway to Iceland). Hence, previous records from Portugal ( Amoureux 1974a) and the Bay of Biscay ( Amoureux 1973; Aguirrezabalaga et al. 2002) are here referred to P. florencioi sp. nov. However, caution should be exercised as not all the Iberian or European records of P. quadricuspis (or its synonyms) may represent P. florencioi sp. nov. e.g. Amoureux (1972) ( O. quadricuspis from Galician shelf and slope, reported as having only tridentate hooks in anterior parapodia and subacicular hooks starting from chaetiger 14-16) or Amoureux 1974b ( O. quadricuspis of the bank Le Danois (= El Cachucho), northern Spain, reported as bearing the first five chaetigers with tridentate hooks and subacicular hooks from chaetiger 20).

Etymology. It is a pleasure to dedicate this new species to Florencio Aguirrezabalaga in recognition of his numerous studies on Cantabrian polychaetes.

Distribution. Atlantic Iberian Peninsula (Spanish and Portuguese coasts) and Cantabrian Sea, Bay of Biscay, East Atlantic.

Figures

FIGURE 5. Paradiopatra florencioi sp. nov. Scanning electron micrographs (A – C, E); photograph (D). A, anterior end, dorsal view; B, anterior end, ventral view; C, detailed view of prostomium and peristomium; D, specimens partly extending from tubes; E, anterior end, showing detail of median chaetigers, dorsolateral view.

FIGURE 6. Paradiopatra florencioi sp. nov. Line drawings. A, parapodium chaetiger 2, anterior view; B, parapodium chaetiger 3, anterior view; C, bidentate pseucompound hook of chaetiger 2; D, tridentate pseudocompound hook of chaetiger 2; E, maxillae; F, mandible.

FIGURE 7. Paradiopatra florencioi sp. nov. Scanning electron micrographs. A, parapodium chaetiger 1, posterior view; B, chaetigers of median body region showing pectinate branchiae; C shafts of pseudocompound hooks of chaetiger 2, inset showing detail of scattered spines; D, pectinate chaeta of chaetiger 14; E, chaetal compliment of chaetiger 15 showing subacicular hooks in foreground; F, chaetal compliment of chaetiger 30 showing the two types of pectinate chaetae; G, pectinate chaeta with rolled lateral margins from chaetiger 30; H, flat pectinate chaeta from chaetiger 30.

FIGURE 8. Graphs illustrating relationship between size and certain features in Paradiopatra florencioi sp. nov. A, relationship between body width of specimens and the maximal number of branchial filaments (N = 30); B, relationship between body width of specimens and origin of subacicular hooks (N = 30).

FIGURE 11. Paradiopatra spp. Scanning electron micrographs of cuticular pore patterns of ventral glandular pads. Left: overall view, right: detailed view. A and B, P. capbretonensis; C and D, P. bihanica; E and F, P. florencioi sp. nov.