Levinsenia demiri 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 : 152-155

Levinsenia demiri Çinar, Dagli & Açik, 2011

( Figures 2–4 )

Levinsenia demiri Çinar, Dagli & Açik, 2011:2124–2128 , Figs 5–6 .

Material examined. ESFM-POL/2013-1271 , 06 June 2013, Y1, 40°01’27’’N, 26°13’24’’E, 10 m, mud, 1 specimen ; ESFM-POL/2013-1272 , 06 June 2013, Y1, 40°00’32’’N, 26°13’04’’E, 25 m, mud, 4 specimens ; ESFM-POL/2013- 40 , 07 June 2013, Y4, 40°18’09’’N, 26°35’15’’E, 50 m, sand, 8 specimens ; ESFM-POL/2013-49 , 07 June 2013, Y5, 40°20’55’’N, 26°40’38’’E, 25 m, mud, 11 specimens ; ESFM-POL/2013-37 , 07 June 2013, Y6, 40°26’03’’N, 26°41’59’’E, 25 m, mud, 74 specimens ; ESFM-POL/2013-55 , 07 June 2013, Y7, 40°24’28’’N, 26°51’24’’E, 25 m, maerl bed, 13 specimens ; ESFM-POL/2013-71 , 07 June 2013, Y7, 40°25’09’’N, 26°51’18’’E, 50 m, mud, 6 specimens ; ESFM-POL/2013-74 , 08 June 2013, Y 9, 10 m, 40°26’20’’N, 27°11’32’’E, mud with gravel and shell fragments, 1 specimen ; ESFM-POL/2013-78 , 08 June 2013, Y9, 40°26’25’’N, 27°11’29’’E, 25 m, mud, 1 specimen ; ESFM-POL/2013-85 , 07 June 2013, Y10, 40°28’24’’N, 26°57’30’’E, 50 m, mud with Lithothamnion sp., 11 specimens ; ESFM-POL/2013-86 , 08 June 2013, Y11, 40°35’55’’N, 27°05’25’’E, 25 m, mud with Turitella communis , 30 specimens ; ESFM-POL/2013-64 , 08 June 2013, Y12, 40°40’23’’N, 27°16’31’’E, 25 m, mud, 8 specimens ; ESFM-POL/2013-545 , 08 June 2013, Y12, 40°39’44’’N, 27°17’00’’E, 50 m, mud with Amphiura filiformis , 2 specimens ; ESFM-POL/2013-604 , 08 June 2013, Y 15, 50 m, 40°25’41’’N, 27°27’57’’E, mud, 2 specimens ; ESFM-POL/2013-1083, 09 June 2013, Y16, 40°24’13’’N, 27°39’47’’E, 41 m, mud, 3 specimens; ESFM-POL/2013- 1086 , 09 June 2013, Y17, 40°39’58’’N- 27°41’08’’E, 50 m, mud, 24 specimens ; ESFM-POL/2013-1089 , 09 June 2013, Y17, 40°41’03’’N, 27°39’52’’E, 100 m, mud, 3 specimens ; ESFM-POL/2013-1090 , 10 June 2013, Y18, 40°54’28’’N, 27°33’24’’E, 100 m, mud with shell fragments, 10 specimens ; ESFM-POL/2013-1092 , 12 June 2013, Y19, 40°59’52’’N, 27°41’59’’E, 10 m, muddy sand with Lithothamnion sp., 1 specimen ; ESFM-POL/2013-1093 , 12 June 2013, Y19, 40°57’28’’N, 27°42’16’’E, 50 m, mud witn shell fragmnets, 1 specimen ; ESFM-POL/2013- 1094 , 12 June 2013, Y19, 40°56’10’’N, 27°44’16’’E, 100 m, muddy sand, 22 specimens ; ESFM-POL/2013-1096 , 12 June 2012, Y20, 40°56’23’’N, 27°55’23’’E, 100 m, mud, 8 specimens ; ESFM-POL/2013-1097 , 15 Jun 2013, Y24, 40°57’20’’N, 28°07’21’’E, 100 m, sand with muddy shell fragments, 3 specimens ; ESFM-POL/2013-1099 , 16 June 2013, Y25, 40°24’48’’N, 28°20’41’’E, 25 m, sandy mud with Amphiura filiformis . 21 specimens ; ESFM-POL/2013-1102, 16 June 2013, Y26, 40°22’36’’N, 28°39’41’’E, 25 m, muddy sand with shell fragments, 30 specimens; ESFM-POL/2013-1105 , 17 June 2013, Y29, 40°32’39’’N, 28°46’42’’E, 50 m, muddy sand, 1 specimen ; ESFM-POL/2013-1106 , 24 June 2013, 40°54’50’’N, 28°52’12’’E, Y 34, 100 m, sandy mud with shell fragments, 1 specimen ; ESFM-POL/2013-1024 , 19 June 2013, Y40, 40°43’12’’N, 29°17’33’’E, 500 m, mud, 1 specimen ; ESFM-POL/2013-1107, 20 June 2013, Y42, 40°45’43’’N, 29°29’39’’E, 50 m, mud, 2 specimens; ESFM-POL/2013-1108 , 26 June 2013, Y50, 41°12’16’’N, 29°07’25’’E, 10 m, sand, 1 specimen .

Description. All specimens incomplete, 5.49– 19 mm long, 0.15–0.20 mm wide for 33–120 chaetigers. Color in alcohol whitish. Body long, thin, fragile, width of prebranchial and branchial regions nearly same, most anterodorsal side slightly swollen, getting gradually thinner from post branchial region to posterior end; having a black tube ( Fig. 2A ).

Prostomium conical, longer than wide (ratio length / width: 1.20); anterior part rounded with an eversible palpode ( Figs 2B ; 3 A–B; 4A), without eyes. A pair of nuchal organs as narrow deep, short slits, as vertical lines on dorso-lateral sides of posterior part of prostomium; without cilia and pigmentation. Cilia patches, cheek organs and lateral organs absent on prostomium ( Fig. 4A ).

Peristomium indistinct on dorsal and lateral sides, only discernable under SEM, partly fused with anterior margin of chaetiger 1 on dorsal side ( Fig. 4A ). Mouth with three buccal lips; two placed anteriorly, one placed posteriorly, with seven longitudinal folds, extending to anterior margin of chaetiger 1. A pair of ciliary slits (csal) present on anterior margin of anterior lips ( Figs 3 A–C).

Branchiae 4–6 pairs, beginning on chaetiger 6, not fused with notopodia; dorso-ventrally flattened, cylindroconical shaped, with a rounded tip; dense ciliary bands present on both sides of outer margin of branchiae, tip naked ( Figs 3 E–F); 100 µm long in anterior part, 106 µm long in middle part, 92 µm long in posterior part of branchial region.

A dense dorsal ciliary band (dcb) existing on mid-dorsal transversal line of each branchial chaetiger; a short dorsal ciliary band (sdcb) arranged in a transversal line, present on ventral side of each branchial base. Ciliary bands absent on ventral side of body. Dorso-lateral irregular pores (dlip) present and irregularly distributed on ventral side of branchiae ( Fig. 3F ).

Interramal lobes and notopodial papilla absent. Notopodial postchaetal lobes short, thick and cirriform on first six chaetigers (prebranchial region); long and digitiform between chaetigers 7–10 (branchial region); short and cirriform on posterior chaetigers. Neuropodial postchaetal lobes and ventral lobes absent ( Figs 3 E–F; 4A–C).

Lateral sense organs present on all chaetigers, located between notopodia and neuropodia, just posterior to notopodial postchaetal lobes; more or less rounded in shape with irregularly clustered pores from prebranchial region to middle part of branchial region; more or less elliptical in shape with irregularly clustered pores from middle part to posterior part of branchial region; straight lined in shape with regularly clustered pores from posterior part of branchial region to end of body ( Figs 3 D–E; 4B–C); with 10–12 pores in prebranchial region (long axis of organ: 3–4 μm), with 14–15 pores (long axis: 6–7 μm) in branchial region; with 25–30 pores (long axis: 8–9 μm) in posterior region; with flexible cilia distinctly protruding from opening or embedded into pore.

Three main types of chaetae present on chaetigers: capillary, limbate and modified neurochaeta ( Fig 4 A–C).

Limbate chaetae present on both notopodia and neuropodia of chaetigers, starting from chaetiger 1 to chaetiger 6–13, arranged in two rows, long, thin and straight with fibrils along edge (hirsute), colorless; in notopodia numbering 7–10, ca. 125 µm long, positioning ventral to dorsal in fascicle; in neuropodia numbering 8–12, ca. 112 µm, slightly sigmoid, positioning dorsal to ventral in fascicle ( Fig 4 A–B).

Capillary chaetae starting from chaetiger 7–13 and present on all subsequent chaetigers, arranged in bundles; in middle notopodia numbering 7–9 in each ramus and 125 μm long, in posterior notopodia numbering 4–5 in each ramus and 45 μm long; in middle neuropodia numbering 8–10 in each ramus and 123 μm long, in posterior neuropodia numbering in 2–3 each ramus and 40 μm long.

Modified neuropodial chaetae present from chaetiger 14 to end of body; numbering 4–6 in each neuropodium, arranged in one row, superior chaetae relatively long, inferior chaetae shorter (average length: 28 μm) and much curved, hook shaped, terminal region strongly curved with fibrillar hood on convex side ( Figs 2C ; 4C ).

Pygidium missing.

Reproduction. Eggs were found in some specimens of Levinsenia demiri collected from the Sea of Marmara. They usually first occurred at chaetiger 26 and continued to the posterior end and numbered six in each chaetiger. The egg diameter varied between 13 and 21 μm.

Remarks. The specimens of Levinsenia demiri from the Sea of Marmara are closely identical to its original description ( Çinar et al. 2011). However, the present paper emended some characters to the description such as ciliary slits, dorsal ciliary band, dorso-lateral irregular pores, lateral sense organs and limbate chaetae

Habitat and Distribution. Levinsenia demiri was found on soft substrata at 10–100 m depths in the study area. Previous works reports the species from similar substrata between 10–1200 m depths in the eastern ( Çinar et al. 2011; 2014; Katsiaras & Simboura 2015) and western ( Langeneck et al. 2017) Mediterranean Sea.

Figures

FIGURE 2. Levinsenia demiri (ESFM-POL/2013-1086).A, General view of body with a delicate black tube; B, Lateral view of anterior end; C, Modified neurochaeta from chaetiger 30. Scale bar: A, 550 µm; B, 134 µm; C, 15 µm.

FIGURE 3. Levinsenia demiri (ESFM-POL/2013-1102). A, Ventral view of prostomium and peristomium; B, Ventro-lateral view of prostomium and peristomium; C, Ciliary slit on anterior lip; D, Lateral sense organ from branchial region; E, Lateral view of chaetigers 4–6; F, Dorsal view of branchial chaetigers. Scale bar: A, 44 µm; B, 45 µm; C, 11 µm; D, 2 µm; E, 59 µm; F, 57 µm. Abbrevations: csal, ciliary slit; dcb, dorsal ciliary band; dlip, dorso-lateral irregular pores; ep, eversible palpode; lso, lateral sense organ; ntpcl, notopodial postchaetal lobe; sdcb, second dorsal ciliary band.

FIGURE 4. Levinsenia demiri (ESFM-POL/2013-1102). A, Antero-lateral view of prostomium; B, Lateral view of chaetigers 2 and 3 with limbate chaetae; C, Parapodium from posterior chaetiger with notopodial postchaetal lobe, capilary chaetae and modified neurochaetae. Scale bar:A, 50 µm; B, 25 µm; C, 13 µm.Abbrevations: cc, capilar chaeta; lc, limbate chaeta; lso, lateral sense organ; mnc, modified neurochaetae; ntpcl, notopodial postchaetal lobe.

FIGURE 5. Levinsenia kosswigi (ESFM-POL/2013-1140). A, General view of anterior end with a black, delicate tube; B, An- terio-lateral view of prostomium and first two chaetigers with a lobate proboscis; C, Modified neurochaetae from a posterior chaetiger. Scale bar: A, 884 µm; B, 156 µm; C, 41 µm. Abbrevation: a, annulation.

FIGURE 6. Levinsenia kosswigi (ESFM-POL/2013-79). A, Lateral view of lobate proboscis; B, Dorsal view of middle bran- chial chaetigers; C, Notopodial postchaetal lobe emerging on branchia in middle branchial chaetiger; D, Lateral sense organ on posterior chaetiger; E, Parapodium from posterior region with modified neurochaetae, notopodial postchaetal lobe and lateral sense organ. Scale bar:A, 58 µm; B, 84 µm; C, 27 µm; D, 4 µm; E, 37 µm. Abbreviations: ant, anterior region; cho, cheek organ; bran, branchia; lso, lateral sense organ; ntpcl, notopodial postchaetal lobe; post, posterior region; prob, proboscis.