Paucibranchia cinari Molina-Acevedo 2018, n. comb.
Creators: name: Molina-Acevedo, Isabel C.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Eunicida
Eunicidae
Paucibranchia
Paucibranchia cinari

description: Paucibranchia cinari (Kurt-Sahin, 2014) n. comb.
Figures 19–22, Tables 1, 3
Marphysa disjuncta Kurt-Sahin & Çinar 2009:145 –150, Figs. 2, 3 non Hartman, 1961
Marphysa cinari Kurt-Sahin, 2014:3 –9, Figs. 2–5.
Material examined. Topotype material: ESFM-POL /2013–1023 (1), sta. Y5, Sea of Marmara, 40°21'21''N 26°39'59''E, 0 7 Jun 2013, in mud with Amphiura, box corer, 50 m, coll. TUBITAK 111Y268 Project. ESFM-POL / 2013–1024 (1), sta. Y6, Sea of Marmara, 40°25'23''N 26°44'03''E, 0 7.06.2013, in mud with Amphiura, box corer, 50 m, coll. TUBITAK 111Y268 Project.
Description. Topotype ESFM-POL/2013–1023 incomplete, broken into three parts (first with 88, second with 25, last part with 41) with 154 chaetigers, L10= 3.9 mm, W10= 1.5 mm, the fragment with TL= 42 mm. Anterior region of body with convex dorsum, and flat ventrum, without groove; body depressed from chaetiger 6, widest at chaetiger 7, tapering after chaetiger 92.
Prostomium entire, 1 mm long, 1 mm wide, frontally rounded, without median sulcus (Fig. 19A–D), ventral sulcus deep (Fig. 19B, D). Prostomial appendages in a semicircle, equidistant. Palps reaching first chaetiger; lateral antennae reaching third chaetiger; median antennae reaching fifth chaetiger. Palpophores and ceratophores ringshaped, short, slender; palpostyles and ceratostyles tapering, slender, without articulation. Eyes absent.
Peristomium wider than prostomium (1 mm long, 1.8 mm wide), first ring two times longer than second ring, separation between rings distinct on all sides (Fig. 19A–D). Inferior lip without central depression (Fig. 19B, D).
Maxillary apparatus with MF= 1+1, 7+7, 9+0, 3+7, 1+1 (Fig. 20A). Maxillary carriers 1.8 times shorter than length of MI. MI forceps-like; closing system 7 times shorter than length of MI; ligament between MI and MII not sclerotized (Fig. 20A). MII wide; with teeth curved, sharped; cavity opening oval, 2.8 times shorter than length of MII; ligament between MII and MIII, and right MIV, not sclerotized (Fig. 20A). MIII short; with triangular teeth; with attachment lamella not sclerotized (Fig. 20A). Left MIV with teeth the similar size; attachment lamella rectangular, situated in short central portion of the maxilla edge. Right MIV with three distal bigger teeth; attachment lamella rectangular, situated in a short central portion of the maxilla edge (Fig. 20A). MV square, with a short rounded tooth (Fig. 20A). Mandibles dark; with whitish cutting plates, with around 12 growth rings (Fig. 20B).
Branchiae pectinate with up to 14 filaments, in chaetigers 14–27 (Figs. 19C; 21C). Number of branchial filaments per chaetiger in order anterior-posterior: 9, 10, 12, 14, 14, 14, 14, 13, 13, 12, 12, 12, 12, 4. Branchial filaments as long as dorsal cirri.
First two parapodia smallest; most developed in chaetigers 4–36, following ones becoming gradually smaller. Notopodial cirri conical, increasing in size from chaetiger 5 (Ldc3: 0.40 mm; Ldc10: 0.48 mm), from chaetiger 40, gradually decreasing in width and increasing in length; in posterior region filiform, 1.7 times longer than prebranchial region ones (Ldc92: 0.67 mm); Hayashi & Yamane’s organ present (Fig. 21A–E). Prechaetal lobes as a transverse fold in all chaetigers (Fig. 21A–E). Chaetal lobes in chaetigers 1–20, rounded, shorter than postchaetal lobes, with aciculae emerging dorsal to midline; from chaetiger 21, triangular, longer than other lobes, with aciculae emerging in midline (Fig. 21A–E). Postchaetal lobes well developed in chaetigers 1–39, bluntly conical, thicker and longer in branchial region; decreasing in size in chaetigers 26–39, following ones inconspicuous (Fig. 21A–E). Ventral cirri digitiform in chaetigers 1–6; in chaetigers 4–40 with oval swollen base and digitiform tip; from chaetiger 41, digitiform, gradually reducing in size posteriorly (Fig. 21A–E).
Aciculae blunt; with reddish basal end, distally translucent; in anterior region one aciculae darker than the others; in posterior chaetigers color intensity decreases (Figs. 21A–E; 22F). First three chaetigers with 2 aciculae; in chaetigers 4–12 with 3 aciculae; in chaetigers 13–30 with 2 aciculae; from chaetiger 31, with only one acicula.
Limbate chaetae of two sizes in same chaetiger, larger in anterior region, reduced in number around chaetiger 16. Two types of pectinate chaetae; in anterior chaetigers, isodonts narrow with long and slender teeth, with 4–8 pectinate, with up to 6–9 teeth, with oblique distal edge (Fig. 22D); in median-posterior chaetigers isodonts narrow with short and slender teeth, with 3–4 pectinate, with up to 7–10 teeth, with transverse distal edge (Fig. 22E). Compound spinigers in all chaetigers, two-sized, reduced in number in median-posterior region (Fig. 22A–B). Compound falcigers present only in posterior region, from chaetiger 120, one per chaetiger, with short blade, with triangular teeth, of similar size, distal tooth directed upward, proximal tooth directed laterally. Subacicular hooks unidentate, with reddish basal end, distally translucent, starting in chaetigers 34L–33R; with one hook per chaetiger (Fig. 22C).
Variation. Material examined varied in the following features: L10= 3.9–6.5 mm, W10= 0.9–2.5 mm. Palps reaching second peristomial ring or first chaetiger. Lateral antennae reaching middle of first or third chaetiger. Median antenna reaching middle of second or five chaetiger. The maxillary formula varies as follows: MII 6–7+6– 7, MIII 6–9, MIV 3–4+7. The proportion of maxillary apparatus varies as follows: maxillary carriers with respect to the MI varies 1.8–2.3 times; closing system with respect to the MI varies 7–10 times; cavity opening with respect to MII varies 2.8–3.7 times. Branchiae from chaetigers 12–14 to chaetigers 22–29. Maximum number of branchial filaments varied from 12 to 14. Well developed postchaetal lobe in first 35–65 chaetigers. End of ventral cirri with swollen base in chaetigers 36–53. Start of subacicular hooks in chaetigers 28–38.
Distribution. Sea of Marmara, Eastern Mediterranean.
Remarks. The specimens from the eastern Mediterranean were previously identified as M. disjuncta (California, USA) (Kurt-Sahin & Çinar 2009); however, after due comparison with topotype specimens of M. disjuncta, Kurt-Sahin (2014) concluded that the Mediterranean specimens belonged to a different species, M. cinari (currently P. cinari n. comb.).
Kurt-Sahin (2014) stated that P. cinari n. comb. differs from P. disjuncta n. comb. and P. kinbergi n. comb. by the presence of a hood at the distal end of the subacicular hook. However, my observations on the material here referred to P. disjuncta n. comb. suggest that the valves that form the hood are present (Fig. 29G). These valves are likely to come off easily since they were not present in some subacicular hooks in specimens of P. cinari n. comb. and P. disjuncta n. comb. Thus, considering the presence/absence of the hood can be a problematic diagnostic character to separate the species.
Paucibranchia cinari n. comb. is similar to P. disjuncta n. comb., P. gilberti n. sp. and P. kinbergi n. comb. based on the presence of unidentate subacicular hooks and spinigers in all chaetigers. However, P. cinari n. comb. differs from P. disjuncta n. comb. and P. kinbergi n. comb. by having dorsal cirri in the posterior chaetigers 1.7 times longer than in pre-branchial chaetigers, rounded chaetal lobe in the anterior region, and postchaetal lobe bluntly conical in pre- and branchial region; whereas in P. disjuncta n. comb. and P. kinbergi n. comb. dorsal cirri in the posterior chaetigers are 2.7 times longer than pre-branchial region, rectangular chaetal lobe in anterior region, and postchaetal lobe conical in P. disjuncta n. comb. and tongue-shaped in P. kinbergi n. comb.. In addition, P. cinari n. comb. lacks eyes; whereas in P. disjuncta n. comb. they are present. The comparison with P. gilberti n. sp. is provided in Table 4.
description: Published as part of Molina-Acevedo, Isabel C., 2018, Morphological revision of the Subgroup 1 Fauchald, 1970 of Marphysa de Quatrefages, 1865 (Eunicidae: Polychaeta), pp. 1-125 in Zootaxa 4480 (1) on pages 31-35, DOI: 10.11646/zootaxa.4480.1.1, http://zenodo.org/record/1453031