Prionospio (Prionospio) ergeni, Dagli, Ertan & Çinar, Melih Ertan, 2009

Dagli, Ertan & Çinar, Melih Ertan, 2009, Species of the subgenera Aquilaspio and Prionospio (Polychaeta: Spionidae: Prionospio) from the southern coast of Turkey (Levantine Sea, eastern Mediterranean), with description of a new species and two new reports for the Mediterranean fauna, Zootaxa 2275, pp. 1-20 : 7-11

publication ID	https://doi.org/ 10.5281/zenodo.191050
DOI	https://doi.org/10.5281/zenodo.6215056
persistent identifier	https://treatment.plazi.org/id/9F7A3A46-E047-145C-FF0D-FC88FE5D6940
treatment provided by	Plazi
scientific name	Prionospio (Prionospio) ergeni
status	sp. nov.

Treatment

Prionospio (Prionospio) ergeni View in CoL n. sp.

Figures 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5

Material examined. Holotype: ESFM –POL/05–3212, 15 September 2005, Iskenderun Bay, K10, 36°42΄15"N, 34°28΄00"E, 5 m, sand [salinity: 39.1 psu, temperature: 29.1°C, dissolved oxygen concentration: 6.55 mg/l]. Paratypes: ESFM –POL/05–219, 2 specimens, 14 September 2005, Iskenderun Bay, K8, 36º45΄40΄΄N, 36º11΄58΄΄E, 5 m, sand; ESFM –POL/05–308, 3 specimens, 14 September 2005, Iskenderun Bay, K9, 36º54΄22΄΄N, 35º58΄0 5΄΄E, 5 m, sand; ESFM –POL/05–348, 21 specimens, 15 September 2005, Iskenderun Bay, K10, 36º45΄59΄΄N, 35º47΄18΄΄E, 5 m, sand; ESFM –POL/05–3213, 3 specimens, 20 September 2005, Akkuyu, K22, 36º08΄17΄΄N, 33º32΄53΄΄E, 3 m, sand; ESFM –POL/05–3215, 1 specimen, 21 September 2005, Aydincik, K24, 36º09΄11΄΄N, 33º20΄33΄΄E, 5 m, sand; ESFM –POL/05–1351, 1 specimen, 22 September 2005, Anamur, K27, 36º01΄17΄΄N, 32º48΄14΄΄E, 5 m, sand; ESFM –POL/05–3214, 1 specimen, 23 September 2005, Mersin Bay, D28, 36º03΄37΄΄N, 32º53΄11΄΄E, 25 m, muddy sand; ESFM –POL/05–1454, 10 specimens, 24 September 2005, Antalya Bay, K30, 36º19΄16΄΄N, 32º14΄0 7΄΄E, 5 m, sand.

Description. All specimens incomplete, holotype 6.6 mm long, 0.24 mm wide, with 38 chaetigers. Body slender, enlarged anteriorly, gradually tapering to posterior end. Color in alcohol opaque white. Prostomium truncate on anterior margin, slightly inflated at level of eyes, tapering posteriorly to form narrow caruncle extending to chaetiger 2; without anterior or lateral marginal peaks. Four eyes present, anterior pair small and rounded; posterior pair large and crescent-shaped ( Fig. 3 View FIGURE 3 A–B). Peristomium fused to chaetiger 1, not forming lateral wings; palps thickened, extending posteriorly for 7–8 chaetigers, with small ripples on the edge of the palps ( Fig. 3 View FIGURE 3 B).

Branchiae present from chaetiger 2 to 5; 4 pairs; first 3 pairs pinnate, last pair apinnate; each pinnate branchia with digitiform pinnules ( Figs. 3 View FIGURE 3 ; 4A, C; 5 A–C). First pair largest, extending to chaetiger 5, with dense digitiform pinnules except on distal and subdistal parts ( Fig. 5 View FIGURE 5 A); second and third pairs equal in length with few pinnules not extending to tip; shorter than first pair ( Fig. 5 View FIGURE 5 B); last pair of branchiae apinnate narrow, shorter than others, heavily ciliated ( Fig. 5 View FIGURE 5 C).

Parapodia of chaetiger 1 reduced; notopodial and neuropodial postsetal lamellae smaller than those of succeeding chaetigers, with capillary chaetae only ( Fig. 3 View FIGURE 3 A). Notopodial lamella foliaceous, largest in branchial region; subsequent parapodia with heart-shaped lamellae, posterior parapodia with rounded lamellae ( Figs. 3 View FIGURE 3 A, 5A–C). Dorsal crests first present on chaetiger 7, continuing through chaetiger 19 (chaetigers 24–25 in paratypes) ( Fig. 5 View FIGURE 5 D–F). Neuropodial postchaetal lamellae small, somewhat leaf-shaped on chaetiger 2; largest, subrectagular on chaetiger 3 ( Fig. 3 View FIGURE 3 A); gradually becoming rounded, smallest in last posterior chaetigers ( Fig. 5 View FIGURE 5 G–H). Interparapodial pouches absent.

Anterior noto- and neuropodial capillaries moderately granulated, with thin sheath ( Fig. 5 View FIGURE 5 I); chaetae arranged in two rows; chaetae of anterior row shorter than those of posterior row. Neuropodial hooded hooks present from chaetiger 16 (18 in paratypes), numbering up to 7 per fascicle; notopodial hooded hooks from chaetiger 30, numbering up to 4–5 per fascicle; hooks with 4–5 pairs of small teeth above main fang ( Figs. 4 View FIGURE 4 B, 5J), secondary hood conspicuous; hooks accompanied by capillaries throughout. Ventral sabre chaeta first present on neuropodia of chaetiger 10; lightly granulated; numbering one or two per fascicle ( Fig. 5 View FIGURE 5 K).

Pygidium missing on all specimens.

Remarks. Prionospio (Prionospio) ergeni n. sp. is easily distinguished from other species of the genus in having three pairs of pinnate branchia on chaetigers 2–4 and one pair of apinnate branchiae on chaetiger 5, and a weakly developed dorsal crest on chaetiger 6. Other species of Prionospio have other combinations of pinnate and apinnate branchiae, but none have digitiform pinnules on the first three pairs of branchiae. Prionospio (P.) plumosa Sars, 1872 and P. (P.) tripinnata Maciolek, 1985 also have three pairs of pinnate branchiae and one pair of apinnate branchiae, but these two species can be easily distinguished from P. (P.) ergeni n. sp. by the arrangement and morphological features of the branchiae. Prionospio (P.) tripinnata , which was originally described from the Mediterranean Sea at 500 and 509 m by Maciolek (1985), has pinnate branchiae on chaetigers 2, 3, and 5, and apinnate branchiae on chaetiger 4. Other differences between P. (P.) ergeni n. sp. and P. (P.) tripinnata are: (1) eyes are absent in P. (P.) tripinnata vs. present in P. (P.) ergeni n. sp., (2) the pinnate branchiae on chaetiger 3 of P. (P.) tripinnata , which has sparse pinnules, are shorter than those on chaetigers 2 and 4 vs. equal in length in P. (P.) ergeni n. sp., and (3) neuropodial hooded hooks are present from chaetiger 12 in P. (P.) tripinnata vs. chaetiger 16 in P. (P.) ergeni n. sp. Prionospio (P.) plumosa , which was originally described from Norway by Sars (1872), has a branchial arrangement similar to that of P. (P.) tripinnata but differs from it mainly in having long pinnate branchiae on chaetiger 3 (vs. short branchiae in P. (P.) tripinnata ).

Ecology. The highest population density (525 individuals.m -2) of this species was found on sandy substratum at 5 m depth at station K10 (near Yumurtalik Harbour).

Distribution. Eastern Mediterranean Sea.

Etymology. This species is named for Prof. Dr. Zeki Ergen, emeritus scientist from Ege University, who made excellent contributions to the understanding of polychaete diversity inhabiting the Turkish as well as eastern Mediterranean coasts.