Diopatra marocensis Paxton, Fadlaoui and Lechapt, 1995

Fauchald, Kristian, Berke, Sarah Kosting & Woodin, Sarah Ann, 2012, Diopatra (Onuphidae: Polychaeta) from intertidal sediments in southwestern Europe, Zootaxa 3395, pp. 47-58 : 51

Diopatra marocensis Paxton, Fadlaoui and Lechapt, 1995

Plate 2a–b

Diopatra marocensis Paxton, Fadlaoui and Lechapt 1995: 950 –954, figs. 1 and 2.

Material examined. USNM 170584, Sidi Boulbra, Moroccan Atlantic coast (4 paratypes); USNM 170585, Sidi Boulbra, Moroccan Atlantic coast, St. F, November 1990 (5 paratypes), (location given as 31°58’ to 31°52N, 9°26’ to 9°36’W for all material treated in Paxton et al. 1995, including the paratypes listed above).

Diagnosis. . Upper lip with anterior median papilla and narrow ridge between halves. Anterior dorsum without ornamentation. First five chaetigers with bidentate pseudocompound hooks; hoods moderately long and pointed. Subacicular hooks present from chaetiger 15. Pectinate chaetae with 11–12 teeth in anterior chaetigers; in median chaetigers pectinate chaetae have 15–18 teeth.

Description. All specimens incomplete; largest (in USNM 17585) consisting of 77 chaetigers, 25mm long and 4 mm wide at chaetiger 10, forming base for description.

Prostomium rounded (Plate 1a); frontal lips nearly as long as length of prostomium, distinctly separated medially and subulate or digitiform. Bases of palps and antennae large, filling out whole margin of prostomium. Palpophores with 8 rings of which distalmost one about one-third longer than others. Antennophores with 8 or 9 short rings plus a distal ring about twice as long as other rings. Lateral projections absent on palpophores and antennophores. Palps reaching posterior margin of peristomium; lateral antennae reaching chaetiger 3 and median antenna reaching chaetiger 4 or margin between chaetigers 4 and 5. Antennal styles only slightly longer than antennophores; slender and digitiform.

Upper lips (Plate 2b) deeply separated medially with a distinct, rounded papilla between lips, roughly midway along length of gap between lips. Shape of each lip roughly triangular, with an indistinctly marked, truncate distal papilla at far lateral ends. Paired lateral lips cushion-shaped. Lower lips tripartite, with a rectangular median section and paired high wings laterally; lateral end of each wing attached directly to outer edge of lateral lips.

Five first parapodia modified; relatively long and tapering. Preacicular lobe rounded and supplemented by a transverse fold near parapodial bases. Postacicular lobe a low fold covering posterior chaetal bases, apart from a long, tapering median lobe. Both dorsal and ventral cirri long, tapering and cirriform in first four parapodia; ventral cirrus rounded and truncate by chaetiger 5. Unmodified parapodia triangular and directed obliquely dorsally; preacicular and postacicular lobes low, transverse folds; postacicular lobe retaining elongated median lobe in all chaetigers present, median lobe becoming increasingly shorter, and conical in outline in more posterior chaetigers.

Modified anterior parapodia with 4–5 bidentate pseudocompound chaetae with moderately long, pointed hoods. Unmodified parapodia with slender, limbate chaetae with lower part of limbation distinctly serrated. Lowermost limbate chaetae replaced from about chaetiger 15 by single, rarely double, bidentate subacicular hook. Pectinate chaetae present from about chaetiger 6; anterior pectinate chaetae with about 12 teeth; median pectinate chaetae with about 15–20 teeth. Shafts of limbate chaetae and subacicular hooks increasingly copper-colored posteriorly.

Branchiae present from chaetiger 4 through chaetiger 35, each with a relatively short, thick stem and 5 to 6 whirls of short, digitiform filaments.

Jaws distinctly sclerotinized along cutting edges; supporting structures barely sclerotinized except along distal margin. Mandibles distinctly calcified distally in a rounded structure; distal end with a distinct notch near median edge. Maxillary formula is 1+1, 8+8, 6+0, 7+10, 1+1.

Remarks. A very noticeable feature of D. marocensis is the anterior dorsal color pattern. Each of the immediate post-modified segments have paired dorsolateral eyespots with a central white (or light-colored) area bordered by a distinct dark (or black) ring. This pattern was illustrated by Paxton et al. (1995) and is still visible in the nine specimens examined here.

Geographical distribution. Diopatra marocensis is known from the Atlantic Ocean off Morocco and along the west coast of the Iberian Peninsula.