Diopatra neapolitana

Fauchald, Kristian, Berke, Sarah Kosting & Woodin, Sarah Ann, 2012, Diopatra (Onuphidae: Polychaeta) from intertidal sediments in southwestern Europe, Zootaxa 3395, pp. 47-58 : 54-57

Diopatra neapolitana delle Chiaje 1841

Plate 3

Diopatra gallica Quatrefages 1866 (<XREF> Quatrefages, 1866a): 338–340, pl. 6 bis, figs. 1–3. (<XREF> Quatrefages, 1866b). Diopatra neapolitana . Saint-Joseph 1898 (<XREF> Saint-Joseph, 1898): 243–254, pl. 13, figs. 31–33, pl. 14, figs. 34– 39(<XREF> Saint-Joseph, 1898).

Material examined: USNM 1128511, Socoa, France., 27 June 2006, (10); USNM 1128509, Socoa, France, 27 June 2007 (1); USNM 1128510, Aveiro, Portugal, 16 May, 2006 (1); USNM 1128519, Aveiro, Portugal, 16 May, 2006 (9); USNM 1128520, Aveiro, Portugal, 18 May, 2006 (9); Aveiro, Portugal, (1); USNM 1128515, Castropol, Spain, 27 May 2006 (1);. USNM 1128513, Huelva Spain, 1 July 2006, coll. SAW et al. (2, marked specimens 1 and 2); USNM 1128516, Huelva, Spain, 1 July 2006 (8); USNM 1128508, Laredo, Spain, 28 June 2006 (2); USNM 1128512, Laredo, Spain, 28 June 2006 (9).

PLATE 3. Diopatra neapolitana . Delle Chiaje 1841, Aveiro, Portugal, USNM 1128510.

a. dorsal view of anterior showing prostomium with palpophores and antennophores with proximal rings and triangular support for the frontal lips plus the peristomium with peristomial cirri.

b. ventral view of anterior showing upper and upper lips and lower external lips with semicircular lateral ends. Note the rounded papilla at the junction of the four buccal lips

c. distal end of pseudocompound chaeta from first modified chaetiger.

d. subacicular hook from median chaetiger,

e. distal end of median acicula from median chaetiger, showing distal strongly bent end.

f. pectinate chaeta from median chaetiger.

g. anterior view of parapodium 25 showing vertical row of distally bent acicula (see also fig. 3e) and showing positions and emergence of two thick bidentate subacicular hooks, one just below the ventral edge of the limbate chaetae and parallel to those chaetae and one at an angle to the other chaetae and emerging below the lower edge of the limbate chaetae.

h. anterior view of parapodium in first modified chaetiger showing dorsal and ventral cirri, a transverse prechaetal fold, a distally rounded prechaetal lobe covering upper chaetae, the rounded postchaetal lobe and the posteriorly directed elongated postchaetal lobe.

Additional material examined: USNM 5105, Gulf of Naples, Italy, (transferred from Statione Zoologici). Arcachon Beach, France, types of Diopatra gallica collected and identified by Armand de Quatrefages. Arcachon Beach collected and identified by Antoine de Saint-Joseph; these previously reported lots from Arcachon Beach are kept in the Museé National d’Histoire Naturelle, Paris.

Diagnosis: Upper lip with anterior median papilla between halves, ridge absent.. Anterior dorsum without ornamentation. First four to five chaetigers with bidentate pseudocompound hooks; hoods moderately long and pointed. Subacicular hooks present from chaetigers 14-18. Pectinate chaetae with 5-6 teeth throughout body.

Description: Specimen described from Aveiro (USNM 1128510); a complete specimen with approximately 130 segments, 55mm long and about 10mm wide at chaetiger 10. Anterior end dorsally strongly convex and ventrally flattened, median part wider than anterior end with both dorsal and ventral sides weakly convex. Body tapering from about chaetiger 100 to posterior end. Living specimens whitish dorsally and light rose-colored laterally and ventrally with scattered small brown spots, similar spots also present on antennae and palps. A brown band present across chaetiger 5 (retained in most preserved specimens). A few specimens stored in ethanol have brown pigmentation dorsally in the branchial region.

Prostomium rounded posteriorly in dorsal view (Plate 3a) with palps and antennae attached along hemispherical posterior edge. Both palps and antennae very large filling in nearly totally dorsal surface of prostomium (Plate 3a). Palps reaching chaetiger 2 in specimen described; in other specimens reaching chaetigers 1–3. All antennae similar in length, reaching chaetiger 7 in specimen described; in other specimens reaching chaetigers 4–13. Palpophores with five rings in specimen described; other specimens with up to six rings. Antennophores in specimen described with eight rings, other specimens with 4–8 rings. Antennophores and palpophores lack lateral papillae. Nuchal grooves are curved, forming nearly a circle in adults. One pair of small brown eyespots present near bases of lateral antennae. Peristomium as long as first chaetiger. Peristomial cirri about as long as peristomium. Frontal lips attached to sides of a triangular, pointed median prostomial tip. Lips short and blunt possibly contracted. Upper lips (Plate 3b) well separated transversely elongated cushions with a distinct papilla attached near midline. A thin flap of tissue linking frontal and upper lips near base. Tripartite lower lip fused to underlying structure except in far lateral edge, median portion quadratic lateral portions distally rounded with the outer edges forming semi-circular free edges. This lip with a semicircular cross-section, rather than being flattened.

Mandibles weakly sclerotinized with calcareous distal cutting plates. Distal indentations along edge of cutting plates present, but not very distinct. Maxillae white, thick and calcareous. Maxillary formula (based on five specimens): Mx I = 1 + 1; Mx II = 8–9 + 9–10; Mx III = 7–8 + 0; Mx IV = 6–7 + 7–9; Mx V = 1 + 1.

First five parapodia not enlarged, located laterally, projecting laterally, ventrally and slightly anteriorly. Prechaetal lobes (Plate 3h) rounded covering dorsalmost chaetal fascicle. Postchaetal lobes low oblique folds covering chaetal bases distinct; median lobe subulate. Parapodia of chaetiger 6 to about chaetiger 20 increasingly conical and directed dorsally.

Postbranchial parapodia (Plate 3g) bluntly conical, and directed laterally. Prechaetal lobes low folds; postchaetal lobes a similar fold, with a distinct projecting lobe attached medially; medial lobe decreasing in size posteriorly but still recognizable at posterior end of body. First five chaetigers with small ventral protrusions at base of postchaetal lobes. Ventral cirri cirriform on first four chaetigers; rounded in chaetiger 5 and represented by rounded glandular pads in remaining chaetigers. Other specimens examined with cirriform ventral cirri in either four or five chaetigers, apparently independently of size of specimen.

Modified parapodia with 1–2 upper simple chaetae and 4–5 bidentate pseudocompound hooks. Hooks with moderately long pointed hoods (Plate 3c) and two rows of blunt small spines along the shafts. Remaining parapodia mainly with strongly serrated limbate chaetae. Pectinate chaetae flat with straight distal margins; each with 5-7 coarse teeth (Plate 3f). Pectinate setae present from chaetiger 6. First present from chaetigers 14-18 in specimens examined, lower limbate chaetae replaced by two thick bidentate subacicular hooks (Plate 3d) with thin translucent guards. Upper subacicular hook emerging just below ventral edge of limbate chaetae; running parallel to these chaetae; lower subacicular hooks distinctly at an angle to other chaetae emerging well below lower edge of limbate chaetae. Modified parapodia with one or two acicula, each acicula distally tapering to straight blunt tips; in unmodified segments about five acicula in a single row; each acicula distally sharply bent dorsally (Plate 3g).

Branchiae with up to five spiraled whorls of relatively short filaments first present at chaetiger 5 and continuing to chaetiger 34 in specimen examined; posterior extent of branchiae varying from chaetigers 14–37 in other specimens. Position of the last branchia strongly correlated with width of specimens. Best developed branchiae present on chaetigers 6–7; branchiae becoming gradually reduced posteriorly but almost all branchiae with several filaments; only last 1-2 pairs single.

Mandibles weakly sclerotinized with calcareous distal cutting plates. Distal indentations along edge of cutting plates present, but not very distinct. Maxillae white, thick and calcareous. Maxillary formula (based on five specimens): Mx I = 1 + 1; Mx II = 8–9 + 9–10; Mx III = 7–8 + 0; Mx IV = 6–7 + 7–9; Mx V = 1 + 1.

Modified parapodia with 1–2 upper simple chaetae and 4–5 bidentate pseudocompound hooks. Hooks with moderately long pointed hoods (Plate 3c) and two rows of blunt small spines along the shafts. Remaining parapodia mainly with strongly serrated limbate chaetae. Pectinate chaetae flat with straight distal margins; each with 5–7 coarse teeth (Plate 3f). Pectinate chaetae present from chaetiger 6. First present from chaetigers 14–18 in specimens examined lower limbate chaetae replaced by two thick bidentate subacicular hooks (Plate 3d) with thin translucent guards. Upper subacicular hook emerging just below ventral edge of limbate chaetae; running parallel to these chaetae; lower subacicular hooks distinctly at an angle to other chaetae emerging well below lower edge of limbate chaetae. Modified parapodia with one or two acicula, each acicula distally tapering to straight blunt tips; in unmodified segments about five acicula in a single row; each acicula distally sharply bent dorsally (Plate 3g).

Pygidium with four pygidial cirri of which two ventral cirri are longer than two dorsal ones.

Tube cylindrical; covered with debris, mostly sea grass fragments and pieces of shells attached on all sides of tube; permanently buried part of tube thin-walled and covered by fine sand.

Discussion. The specimen from the Gulf of Naples (USNM 4105) is rather poorly preserved; it is larger than the specimens from Aveiro, but resembles them in most features. The structure of the prostomium is essentially identical, including the triangular support for the frontal lips. The upper lips are inflated so the free distal semicircular end is indistinct in this specimen. An unusual feature in both specimens is the triangular support for the frontal lips, and, at least in well preserved material, the semicircular lateral ends to the lower lips.

Geographical distribution. Diopatra neapolitana has been widely reported from the Indian Ocean and the Atlantic Ocean. In addition to the type locality in the Gulf of Naples, we can confirm that the species is present along the Atlantic coasts of Spain, Portugal and France. The other localities must be verified by comparisons of specimens taking into the consideration that even the relatively limited area studied here contains four species with which it may be confused.