Chaetozone elakata Blake and Lavesque, 2017

Çinar, Melih Ertan, Dağli, Ertan & Erdoğan-Dereli, Deniz, 2022, The diversity of polychaetes (Annelida: Polychaeta) in a longterm pollution monitoring study from the Levantine coast of Turkey (Eastern Mediterranean), with the descriptions of four species new to science and two species new to the Mediterranean fauna, Journal of Natural History 56 (33 - 36), pp. 1383-1426 : 1419-1420

Chaetozone elakata Blake and Lavesque, 2017

( Figure 19 )

Chaetozone elakata Blake and Lavesque, 2017 , 567–572; figs 1–3.

Material examined

Levantine Sea. ESFM-POL/2018-073 , 09 August 2018, DALSW2 , 36.701333°N, 28.726°E, 45 m, fine sand with mud, 4 specimens .

Aegean Sea. ESFM-POL/2015-658 , 17 August 2015, off Küçük Menderes River, 37.949444°N, 27.259722°E, 36 m, mud, 3 specimens; ESFM-POL/2018-080 , 03 September 2018, off Büyük Menderes River , 37.533217°N, 27.152833°E, 15 m, mud, 1 specimen .

Sea of Marmara. ESFM-POL/2013-1430 , 10 July 2013, 40.7575°N, 27.356667°E, 100 m, mud, 90 specimens; ESFM-POL/2013-1427 , 06 July 2013, 40.355833°’N-26.666389°’E, 50 m, mud with Amphiura filiformis , 1 specimen; ESFM-POL/2013-1428 , 08 July 2013, 40.580556° N, 27.099722°E, 50 m, mud with Amphiura filiformis , 3 specimens; ESFM-POL/2013- 1429 , 09 July 2013, 40.310833°N, 27.761944°’E, 25 m, mud with Amphiura filiformis , 1 specimen .

Description

Levantine specimens incomplete, largest 20.86 mm long, 0.97 mm wide (middle of expanded region), with 114 chaetigers. Body elongated anteriorly and posteriorly, with a conspicuous expanded region (with or without a dorsal groove) in middle body ( Figure 19 (a–c)). Expanded region generally between chaetigers 11–22; chaetigers 16–17 broadest. Posterior segments tapering, parapodia modified, with spines and capillaries in between forming an almost complete cincture, characteristic of this genus ( Figure 19 (d)). Prostomium somewhat triangular,eyespots absent ( Figure 19 (a–c)).Peristomium narrow,with two annular rings,surmounted by an elongate dorsal crest reaching to anterior margin of chaetiger 1; one pair of dorsal tentacles emerging on second peristomial ring. First segment achaetous. Branchiae first emerging on posterior margin of segment 1 and present on subsequent chaetigers, emerging on posterior margin of anterior segments, more medially on median and posterior segments.

Anterior parapodia with capillaries only. Neuropodial spines first beginning on chaetiger 88, notopodial spines on chaetiger 100; numbering 2–3 with 5–6 capillaries in first appearance, then forming cinctures on last 23–35 chaetigers (in the Sea of Marmara specimens), with 12–13 spines on each side, alternating with a thin capillary chaeta ( Figure 19 (d)). Pygidium as a subtriangular lobe.

Briefly submerging a specimen from the Sea of Marmara in a methyl green solution gave a distinctive colour pattern along the body; a broad green ring is more appearent on the expanded region between chaetigers 14 and 18 ( Figure 19 (c)).

Remarks

The morphology of the specimens of Chaetozone elakata from the eastern Mediterranean closely resembles the original description of the species by Blake and Lavesque (2017).

Distribution

Chaetozone elakata was recently described from the Gulf of Biscay (Northeast Atlantic, France) by Blake and Lavesque (2017), based on individuals found in soft substrata at 62 m depth. This species was commonly found along the coasts of Turkey (Levantine Sea, Aegean Sea and Sea of Marmara) and identified as Chaetozone sp. (with brownish chaetae) in many projects. Individuals of the species from the eastern Mediterranean are morphologically very similar to those from the eastern Atlantic. On the Levantine coast of Turkey, they were found between depths of 14 and 66 m on sandy muddy bottoms.

Figures

Figure 19. Chaetozone elakata ESFM-POL/2018-073 and ESFM-POL/2013-1430: (a) anterior end, dorsolateral view; (b) anterior end, dorsal view; (c) anterior end, dorsal view, stained with methyl green; (d) posterior parapodium, cross section. Scale bar: a = 0.96 mm; b = 0.72 mm; c = 0.98 mm; d = 0.14 mm.