Levinsenia marmarensis Çinar, Dagli & Açik, 2011

Erdoğan-Dereli, Deniz & Çinar, Melih Ertan, 2021, Levinsenia species (Annelida: Polychaeta: Paraonidae) from the Sea of Marmara with descriptions of two new species, Zootaxa 4908 (2), pp. 151-180 : 160-162

Levinsenia marmarensis Çinar, Dagli & Açik, 2011

( Figures 7–8 )

Levinsenia marmarensis Çinar, Dagli & Açik, 2011: 2132–2136 , Figs 9–10 .

Material examined. ESFM-POL/2013-61 , 06 June 2013, Y2, 40°06’59’’N, 26°22’04’’E, 50 m, muddy sand, 2 specimens ; ESFM-POL/2013-98 , 07 June 2013, Y6, 40°26’03’’N, 26°41’59’’E 25 m, mud, 1 specimen ; ESFM-POL/2013-1174, 08 June 2013, Y9, 40°28’09’’N, 27°11’14’’E, 50 m, mud, 1 specimen; ESFM-POL/2013-1175 , 12 June 2013, Y19, 40°56’10’’N, 27°44’16’’E, 100 m, sandy mud with shell fragments, 7 specimens ; ESFM-POL/2013-1176, 12 June 2012, Y20, 40°56’23’’N, 27°55’23’’E, 100 m, mud, 10 specimens; ESFM-POL/2013- 1177 , 15 June 2013, Y24, 40°57’20’’N, 28°07’21’’E, 100 m, muddy sand with shell fragment, 4 specimens ; ESFM-POL/2013-1180, 16 June 2013, Y25, 40°26’49’’N, 28°19’11’’E, 50 m, mud, 2 specimens.

Description. All specimens incomplete, 4.3–14.1 mm, 0.12–0.20 mm wide, with 29–73 chaetigers. Color in alcohol dull white. Body long, slender; anterio-dorsal side slightly swollen, prebranchial region wider than branchial region, body tapering to posterior part ( Figs 7A ; 8 A–B).

Prostomium more or less subtriangular, much longer than wide (ratio length / width: 1.03), anterior part of prostomium slightly rounded with an eversible palpode ( Figs 7A ; 8 B–D), without eyes. In some specimens, a pair of bulges on posterio-lateral side of prostomium ( Fig. 8 C–D). A pair of nuchal organs as narrow, deep, vertical slits, placed on dorso-lateral sides of posterior part of prostomium; cilia protruding out of each slit; without pigmentation ( Fig. 8C ). Cilia patches, lateral organ and cheek organ absent on lateral side of prostomium.

Peristomium indistinct on dorsal and lateral sides, only discernable under SEM, partly fused with anterior margin of chaetiger 1 on dorsal side. Mouth with three buccal lips; two placed anteriorly and one placed posteriorly with six longitudinal folds, extending to anterior margin of chaetiger 1. A pair of ciliary slits (csal) present on anterior margin of anterior lips ( Fig. 8D ).

Dorso-lateral irregular pores (dlip) present, located regularly just posterior to branchiae and irregularly on dorsal side of body ( Fig. 8H ).

Branchiae 6–8 pairs, beginning on chaetiger 7; short, slightly flattened, lanceolate, with a rounded tip, last pair always shorter ( Figs 7A ; 8A, E ); 136 μm long in anterior part, 164 μm long in middle part, 147 μm long in posterior part of branchial region.

Interramal lobes and notopodial papilla absent. Notopodia not fused with branchiae ( Fig 8E ). Notopodial postchaetal lobes short and rounded on first two chaetigers; relatively long and digitiform between chaetigers 3–12; short and rounded in posterior region ( Figs 8E , G–H). Neuropodial postchaetal lobes absent.

Lateral sense organs present on all chaetigers, located between notopodia and neuropodia, just posterior to notopodial postchaetal lobes; elliptical with irregularly clustered pores from prebranchial region to middle part of branchial region; more or less elliptical with irregularly clustered pores from middle part to posterior part of branchial region ( Fig. 8 G–H); with 16–18 pores in prebranchial region (long axis of organ: 11–12 μm), with 10–12 pores (long axis: 4–5 μm) in branchial region.

Two types of chaetae present on chaetigers; capillary and modified neurochaetae ( Fig. 8 F–G).

Capillary chaetae starting in both noto- and neuropodia of chaetiger 1 and present on all subsequent chaetigers, arranged as bundles, colorless; in anterior notopodia, numbering 8–19 in each ramus and ca. 128 μm long; in middle notopodia numbering 4–5 in each ramus and ca. 95 μm long; in posterior notopodia, numbering 2–5 in each ramus and ca. 76 μm long; in anterior neuropodia, numbering 9–10 in each ramus and ca. 139 μm long; in middle neuropodia, numbering 8–10 in each ramus and ca. 136 μm long and in posterior neuropodia, numbering 1–3 in each ramus and ca. 68 μm long.

Modified neuropodial chaetae present from chaetigers 18–20 to posterior chaetigers, numbering 6–8 in each neuropodium, arranged in one row, superior chaetae relatively straight and long, inferior chaetae much shorter and curved, about 20 μm long, hook shaped, strongly curved, with rudimentary, fibrillar hood on convex side, with a naked tip ( Figs 7B ; 8F ).

Pygidium missing.

Remarks. The specimens of Levinsenia marmarensis found in this study matched well with its original description (Çinar et. al. 2011); furthermore, the following characters were described for the first time for Levinsenia marmarensis : ciliary slits, dorso-lateral irregular pores and lateral sense organs.

Habitat and Distribution. The specimens of Levinsenia marmarensis were found on soft substrata between 25 and 100 m depths in the Sea of Marmara. Çinar et al. (2011) previously reported this species in the similar habitat and depths (17–54 m) in same the region. This species was also reported from the Aegean Sea ( Çinar et al. 2014).

Figures

FIGURE 7. Levinsenia marmarensis (ESFM-POL/2013-1175).A, Dorsal view of anterior end of body, stained with Shirlastain- A; B, Modified neurochaeta from chaetiger 70. Scale bar: A, 363 µm; B, 22 µm.

FIGURE 8. Levinsenia marmarensis (ESFM-POL/2013-1177).A, Dorsal view of anterior end of body; B, Anterio-dorsal view of prostomium and first chaetigers; C, Anterio-dorsal view of lateral part of prostomium, arrow pointing the bulge on posteriolateral side of prostomium; D, Anterio-ventral view of lateral part of prostomium, left arrow pointing the bulge on posterio-lat- eral side of prostomium; E, First three branchial chaetigers; F, Modified neurochaetae from posterior chaetiger; G, Notopodium from first chaetiger with lateral sense organ; H, Notopodium from middle branchial chaetiger with notopodial postchaetal lobe, lateral sense organ and dorso-lateral irregular pores. Scale bar: A, 128 µm; B, 37 µm; C, 33 µm; D, µm 46; E, 40 µm; F, 12 µm; G, 11 µm; H, 20 µm. Abbreviations: ant, anterior region; bran, branchia; dlip, dorso-lateral irregular pores; lso, lateral sense organ; csal, ciliary slits of anterior lips; ntpcl, notopodial postchaetal lobe; post, posterior region.

FIGURE 9. Levinsenia materi (ESFM-POL/2013-1113). A, General view of body with a black tube; B, Later view of anterior end of body; C, Modified neurochaetae from posterior chaetiger. Scale bar: A, 500 µm; B, 261 µm; C, 14 µm. Abbreviation: sp, sperm packages within coelomic cavity.

FIGURE 10. Levinsenia materi (ESFM-POL/2013-1111). A, Lateral view of anterior end of body; B, Anterio-dorsal view of prostomium and first chaetigers; C, Lateral view of prostomium; D, Ciliated patch on lateral sides of prostomium. Scale bar: A, 293 µm; B, 152 µm; C, 72 µm; D, 11 µm. Abbreviations: a, annulation; cp, ciliated patch; no, nuchal organ.