Anobothrus amourouxi Bonifácio, Lavesque, Bachelet and Parapar, 2015

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 : 1420-1422

Anobothrus amourouxi Bonifácio, Lavesque, Bachelet and Parapar, 2015

( Figure 20 )

Anobothrus amourouxi ; Bonifácio et al. 2015, 962–967; figs 2–4.

Material examined

Levantine Sea. ESFM-POL/2017-010 , 17 August 2017, SAMSWR, 36.048889°N, 35.935833° E, 71 m, mud with pebbles, 3 specimens; ESFM-POL/2009-205 , 05 August 2009, Mersin Bay, 36.688056°N, 34.82°E, 30 m, mud, 1 specimen; ESFM-POL/2009-208 , 04 August 2009, Mersin Bay , 36.773333°N, 34.670278°E, 15 m, muddy sand, 3 specimens; ESFM-POL/2009 - 213, 03 August 2009, Mersin Bay , 36.621111°N, 34.692778°E, 70 m, mud with pebbles, 1 specimen .

Aegean Sea. ESFM-POL/2016-140 , 17 August 2016, Ildır Bay, 38.454167°N, 26.443889°E, 65 m, mud, 3 specimens; ESFM-POL/2017-32 , 20 August 2017, Edremit Bay, 39.5669°N, 26.91885°E, 23 m, mud with pebble, 1 specimen; ESFM-POL/2018-93 , 30 August 2018, off Meriç River , north Aegean Sea , 40.706833°N, 26.02415°E, 16 m, detritic mud, 1 specimen .

Sea of Marmara. ESFM-POL/2013-343 , 09 July 2013, 40.403611°N, 27.663056°E, 41 m, mud with Amphiura filiformis , 2 specimens .

Description

Largest specimen incomplete, 10.8 mm long, 1 mm long wide. Body slender, thorax cylindrical, tapering towards posterior end ( Figure 20 (a,c)). Colour in alcohol whitish, tube thin layer with silt. Prostomium trilobed, without eyes. Buccal tentacles smooth. Four pairs of branchiae, long tapering to tip, three pairs in a single row, the fourth pair behind the inner most one, no gap between pairs ( Figure 20 (b)). Inner pairs of branchiae with transversal ciliated ridges ( Figure 20 (b)). Paleae long with 16–18 each side. From TU1 (thoracic unciniger), notopodia well developed, rounded and elongated. Thorax with 15 TC (thoracic chaetiger), 12 TU (thoracic unciniger). TU3 with an anterior whitish band ( Figure 20 (a,b)). TU8 with elevated notopodia ( Figure 20 (a)). Notochaeta bilimbate, broad wings (as wide as shaft) on one margin, TU8 with serrated tips ( Figure 20 (d)). TU3 with four short and four long notochaetae; subsequent chaetigers with 4–5 long and 4–5 short notochaetae. TU3 with 46–48 uncini, pectinate, each one with two vertical rows in frontal view with six teeth in lateral view ( Figure 20 (f)). AU1 (abdominal unciniger) with 18–20 uncini, pectinate with 5–6 teeth in lateral view, three vertical rows in frontal view ( Figure 20 (e)). Pygidium unknown.

Reproduction

Some specimens of this species collected in August from the Levantine Sea had eggs in the coelomic cavities of the anterior part of the thoracic region. The egg diameter varied between 75 and 129 μm.

Remarks

Morphologically, the specimens of Anobothrus amourouxi from the eastern Mediterranean closely resemble the original description of the species by Bonifácio et al. (2015).

Distribution

Anobothrus amourouxi is new to the Mediterranean Sea, but this species might have been confused with A. gracilis (Malmgren, 1866) , which was encountered almost in every soft bottom study (muddy substrata, clean water, depth> 10 m) in the Mediterranean Sea. We compared our specimens with those previously identified as A. gracilis on the coasts of Turkey, and realised that they in fact belong to the recently described species A. amourouxi , found in the Bay of Biscay ( France) on soft substrata between depths of 108 and 735 m ( Bonifácio et al. 2015). This species is easily distinguished from A. gracilis in having notochaetae with hirsute tip only on the modified notopodia (vs notochaetae with hirsute tip present on all notopodia in A. gracilis ). Therefore, the previous records of A. gracilis from the Mediterranean should be checked to verify whether it truly occurs in the region.

Figures

Figure 20. Anobothrus amourouxi ESFM-POL/2017-10: (a) anterior part, dorsal view; (b) anterior end, dorsal view; (c) lateral view of body; (d) notochaetae with serrate tip on TU8; (e) abdominal uncini on AU1; (f) thoracic uncini on TU1. Scale bars: a = 1.7 mm; b = 1.1 mm; c = 2.2 mm; d = 36 µm; e = 22 µm; f = 23 µm. Abbreviation. TU: thoracic unciniger. The arrow in (a) indicates a white band on dorsum of uniciniger 3.