Prionospio (Minuspio) anatolica Dagli & Çinar, 2011, sp. nov.

Prionospio (Minuspio) anatolica sp. nov.

(Figs 2–5, 13 B)

Material examined: Holotype. ESFM –POL/2005–398, 10 September 2005, Iskenderun Bay, G5, 36º43ʹ44ʹ N– 35º43ʹ39ʹ E, 25 m, sandy mud [salinity: 39.2 psu, temperature: 27.7°C, dissolved oxygen concentration: 5.1 mg/l]. Paratypes. ESFM –POL/ 2005–62, 2 specimens, 9 September 2005, Iskenderun Bay, D9, 36º45ʹ59ʹ N–35º48ʹ18ʹ E, 25 m, muddy sand; ESFM –POL/2005–121, 4 specimens, 10 September 2005, Iskenderun Bay, G4, 36º44ʹ8ʹ N– 35º44ʹ32ʹ E, 50 m, mud; ESFM –POL/2005–237, 6 specimens, 9 September 2005, Iskenderun Bay, G3, 36º51ʹ8ʹ N– 35º55ʹ42ʹ E, 25 m, mud; ESFM –POL/2005–242, 2 specimens, 10 September 2005, Iskenderun Bay, G4, 36º44ʹ8ʹ N–35º44ʹ32ʹ E, 50 m, mud; ESFM –POL/2005–398, 5 specimens, 10 September 2005, Iskenderun Bay, G5, 36 °43'44"N– 35°43'39"E, 25 m, sandy mud; ESFM –POL/2005–504, 131 specimens, 17 September 2005, Mersin Bay, G7, 36º46ʹ41ʹ N–34º39ʹ39ʹ E, 10 m, mud; ESFM –POL/2005–757, 1 specimen, 22 September 2005, Anamur, DT5, 36º45ʹ54ʹ N– 35º51ʹ38ʹ E, 5 m, mud; ESFM –POL/2005–1549, 7 specimens, 6 October 2005, Fethiye Bay, G28, 36º37ʹ48ʹ N–29º06ʹ30ʹ E, 10 m, mud; ESFM –POL/ 2005–2691, 2 specimens, 27 September 2005, Antalya Bay, D37, 36º49ʹ53ʹ N–30º37ʹ0 8ʹ E, 25 m, muddy sand; ESFM –POL/2005–3248, 5 specimens, 10 September 2005, Iskenderun Bay, G5, 36º43ʹ44ʹ N–35°43ʹ39ʹ E, 25 m, sandy mud.

Description. Holotype complete, 0.27 mm wide, 9.51 mm long, with 73 chaetigers. Body slender, enlarged anteriorly, gradually tapering to posterior end. Color in alcohol opaque white. Prostomium anteriorly rounded, slightly inflated at middle of prostomium, tapering posteriorly, forming short caruncle, extending to base of chaetiger 2 (Figs 2 A–B, 4A, 5A–C); with three anterior, two latero–marginal and one anterio–dorsal peaks (Figs 4A, 5B– C). Eyes absent (Figs 2 A–B, 4A). Peristomium partly fused to chaetiger 1, forming moderate lateral wings; palps thickened, as long as 7–9 chaetigers (Fig. 2 A).

Branchiae long, smooth, apinnate, cylindrical, seven pairs on chaetigers 2–8. Pairs one to three longest, extending over nine chaetigers; pairs four to five extending over six chaetigers, and pairs six to seven extending over five chaetigers (Figs 2 A–B, 5A, 13B); all with short ciliae on lateral edges (Fig. 3 A–B), except for last pairs (Fig. 3 C).

Parapodia of chaetiger 1 reduced, neuropodial lamellae small, bluntly rounded, notopodial lamellae absent; both neurochaetae and notochaetae present (Figs 2 A–B, 4A). Notopodial lamellae of chaetiger 2 leaf–like, smaller than those of chaetigers 3–7; neuropodial lamellae smaller, rounded (Fig. 2 A). Notopodial postchaetal lamellae on chaetiger 3 ear–shaped, larger than those on chaetiger 2; neuropodial lamellae largest on chaetiger 3, subrectangular, well developed, ventrally pointed (Figs 2 A–B, 3A). Notopodial lamellae largest on chaetiger 4, subrectangular, dorsally pointed; neuropodial lamellae on chaetiger 4 triangular with somewhat pointed tip, smaller than those on chaetiger 3 (Figs 2 A–B, 3B). Neuropodial lamellae on following chaetigers progressively decreasing in size (Figs 2 B, 3C); middle parapodia with rounded lamellae (Fig. 3 D–E), posterior parapodia with finger–shaped lamellae (Fig. 4B). Notopodial lamellae on chaetigers 5 to 8 triangular with pointed tip, smaller than those on chaetiger 4 (Figs 2 A–B, 3C). Notopodial lamellae on following chaetigers progressively decreasing in size; lamellae on middle parapodia subrectangular or rounded (Fig. 3 D–E), lamellae on posterior parapodia finger–like (Fig. 4B). Dorsal crests and inter–parapodial pouches absent (Figs 2 A, 3E).

4. Prionospio (Minuspio) anatolica sp. nov.: A. Prostomium and first three chaetigers, dorsal view, paratype (ESFM–POL/2005–1214). B. Posterior end, dorsal view, holotype. C. Neuropodial hooded hook on chaetiger 20. D. Ventral sabre chaeta on chaetiger 15. E. Notopodial capillary chaetae on chaetiger 10. Scale bar: A 0.1 mm, B 0.12 mm, C 11.7 Μm, D 16.7 Μm, E 45 Μm.

Capillary chaetae in anterior region distinctly granulated, with thin sheath (Fig. 4E); chaetae arranged in two rows; chaetae of anterior row shorter than those of posterior row (Fig. 4E). Neuropodial hooded hooks present from chaetiger 13 (14–15 in paratypes), up to 8 (range: 5–8) per fascicle. Notopodial hooded hooks present from chaetiger 37 (27–39 in paratypes), up to 4–6 per fascicle (Fig. 3 D). Hooks with four pairs of small teeth above main fang (Figs 4C, 5F), secondary hood conspicuous (Fig, 4C); hooks accompanied by capillaries throughout. Ventral sabre chaetae first present in neuropodia of chaetiger 11; lightly granulated; without distal flament, one (two in paratypes) per fascicle (Figs 4D, 5E).

Pygidium with a long mid–dorsal cirrus and two shorter ventro–lateral cirri (Figs 4B, 5D).

Remarks. Prionospio (Minuspio) anatolica sp. nov., is mainly characterized by having extremely long and thin apinnate branchiae on chaetigers 2–8. The same branchial morphology was reported in the following species; P. (M.) delta Hartman, 1965 from the Atlantic and Pacific Oceans; P. (M.) lighti Maciolek, 1985 from the coast of California; P. (M.) patagonica Augener, 1923 from west Patagonia; P. (M.) perkinsi Maciolek, 1985 from the Gulf of Mexico to New England; P. (M.) pulchra Imajima, 1990 from the coast of Japan; and P. (M.) yuriel Wilson, 1990 from southern Australian coast.

Prionospio (M.) anatolica sp. nov., is similar to P. (M.) pulchra, which was originally described from the coast of Japan (Pacific Ocean) by Imajima (1990) and subsequently from the coast of Galicia, north west Spain (Atlantic Ocean) by Moreira et al. (2000), in the shape of the anterior margin of the prostomium, and the morphology of branchiae, sabre and hooded hooks. However, Prionospio (M.) anatolica sp. nov., differs from it with respect to some important characters; 1– eyes [absent in P. (M.) anatolica sp. nov., vs. present in P. (M.) pulchra], 2– the number of branchiae [7 pairs in P. (M.) anatolica sp. nov., vs. 9–10 pairs in P. (M.) pulchra]; 3– the morphology of branchiae [all branchiae long in P. (M.) anatolica sp. nov., vs. last three pairs shorter than first seven pairs (last pair shortest) in P. (M.) pulchra]; 4– dorsal crests [absent in P. (M.) anatolica sp. nov., vs. present in P. (M.) pulchra]; 5– first occurrence of hooks on parapodia [neuropodial hooded hooks first appeared on chaetigers 13–15 in P. (M.) anatolica sp. nov., vs. on chaetigers 16–17 in P. (M.) pulchra]; 6– morphology of sabre chaeta [without filament in P. (M.) anatolica sp. nov., vs. with filament in P. (M.) pulchra].

Prionospio (M.) anatolica sp. nov., is also similar to P. (M.) delta in that the branchiae are apinnate, extremely long and thin. These two species differ considerably, however, in the shape of the prostomium. The prostomium of P. (M.) delta is broadly triangular, flared on anterior margin and often has a small median peak, whereas that of P. (M.) anatolica sp. nov., is anteriorly rounded, slightly inflated at middle part, and has three anterior and two lateral marginal peaks. Prionospio (M.) delta has six pairs of branchiae, whereas P. (M.) anatolica has seven pairs of branchiae. Dorsal crests absent in P. (M.) anatolica, whereas present dorsal crests on several post–branchial chaetiger in P. (M.) delta. The sabre chaetae first occur on chaetiger 12 in P. (M.) delta vs. on chaetiger 11 in P. (M.) anatolica. The hooded hooks of P. (M.) delta have three pairs of teeth above the main fang, whereas those of P. (M.) anatolica sp. nov., have four pairs of teeth above the main fang. Finally, the pygidium of P. (M.) delta has a short mid–dorsal cirrus (as long as ventro–lateral lobes) and two short and broad ventro–lateral lobes, whereas that of P. (M.) anatolica sp. nov., has a long mid–dorsal cirrus (ca. 2.5 times longer than ventro–lateral cirri) and two short ventro–lateral cirri. Prionospio (M.) anatolica sp. nov., also ecologically differs from P. (M.) delta. The former species was found at depths ranging from 5 to 50 m on the coast of Turkey, whereas the latter was previously reported at depths ranging from 520–2200 m off South, West (Oregon) and East (Delaware) America, West Africa, Gulf of California (Hartman 1965; Maciolek 1985).

Prionospio (M.) anatolica sp. nov., is closely related to P. (M.) lighti, which was first described from the coast of California (Pacific Ocean) by Maciolek (1985), in the morphology of the prostomium, branchiae and chaetae, and the absence of dorsal crests. However they differ from each other in a number of characters. Prionospio (M.) anatolica sp. nov., has no eyes [four small eyes in P. (M.) lighti], 7 pairs of branchiae [6–12 pairs (usually 10) of branchiae in P. (M.) lighti], notochaetae on chaetiger 1 [absent in P. (M.) lighti] and ventral sabre chaetae that are lightly granulated and present from chaetiger 11 [moderately granulated and present from chaetigers 12–14 in P. (M.) lighti].

Prionospio (M.) anatolica sp. nov., is also similar to P. (M.) perkinsi. However, Prionospio (M.) anatolica sp. nov., differs in having five prostomial peaks [seven in P. (M.) perkinsi], no eyes [two distinct eyes in P. (M.) perkinsi], 7 pairs of branchiae [10 pairs of branchiae in P. (M.) perkinsi] and inferior sabre chaetae [absent in P. (M.) perkinsi].

Prionospio (M.) patagonica was originally described from the west Patagonia by Augener (1923), and subsequently from Chile and the western Patagonia by Blake (1983) and Radashevsky et al. (2006). Augener (1923) noted that P. patagonica had two pairs of black eyespots and up to 12 pairs of cirriform branchiae. Hartmann– Schröder (1962) determined that this species had two pairs of reddish eyes and up to ten pairs of branchiae. Blake (1983) noted that P. patagonica had no eyes and hooks with external and distinct internal hoods. Radashevsky et al. (2006) noted that this species had two pairs of dark red eyespots, sabre chaetae beginning from segment 7, and up to 14 pairs of branchiae. Prionospio (M.) anatolica is easily distinguished from P. (M.) patagonica in having no eyes, seven pairs of branchiae, peaks on the prostomium, and sabre chaetae beginning from chaetiger 11.

The other species that shows a close morphological affinity with P. (M.) anatolica is P. (M.) yuriel, which was originally described from the southern Australia (Wilson, 1990). However, these two species are easily separated from each other with respect to the following characters; 1– the shape of the prostomium [anteriorly rounded, slightly inflated at middle part, with five peaks in P. (M.) anatolica sp. nov., vs. narrow and elongate anteriorly, without peaks in P. (M.) yuriel]; 2– eyes [no eyes in P. (M.) anatolica sp. nov., vs. one pair of red eye in P. (M.) yuriel]; 3– nuchal organs [no nuchal organ in P. (M.) anatolica vs. a pair of nuchal organs surrounding the caruncle in P. (M.) yuriel]; 4) number of branchiae [seven pairs in P. (M.) anatolica sp. nov., vs. six to nine pairs in P. (M.) yuriel].

Reproduction. Specimens of Prionospio (Minuspio) anatolica sp. nov., collected in September had eggs in the coelomic cavities between chaetigers 18 and 39; egg diameters were 25–40 Μm (mean: 31.5±5.08 SD, N=20).

Habitat. The highest population density (1310 individuals.m–2) of this species was found in 10 m depth on muddy substratum at station G7 (Mersin Bay).

Distribution. Eastern Mediterranean (Levantine Sea, southern coast of Turkey).

Etymology. The species name refers to type locality, Anatolia (Anadolu in Turkish).