Levinsenia kosswigi 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 : 156-159

Levinsenia kosswigi Çinar, Dagli & Açik, 2011

( Figures 5–6 )

Levinsenia kosswigi Çinar, Dagli & Açik, 2011:2129–2132 , Figs 7–8 .

Material examined. ESFM-POL/2013-38 , 06 June 2013, Y1, 40°00’27’’N, 26°13’24’’E, 10 m, mud, 2 specimens ; ESFM-POL/2013-79 , 07 June 2013, Y4, 40°17’49’’N, 26°35’44’’E, 25 m, maerl bed, 4 specimens ; ESFM-POL/2013-104, 07 June 2013, Y5, 40°20’55’’N, 26°40’38’’E, 25 m, mud, 1 specimen; ESFM-POL/2013-1138 , 07 June 2013, Y8, 40°25’15’’N- 27°03’49’’E, 10 m, mud, 22 specimens ; ESFM-POL/2013-1085 , 09 June 2013, Y17, 40°39’16’’N, 27°41’14’’E, 25 m, fine sand, 1 specimen ; ESFM-POL/2013-1140 , 09 June 2013, Y17, 40°39’58’’N- 27°41’08’’E, 50 m, mud, 1 specimen ; ESFM-POL/2013-592 , 20 June 2013, Y42, 40°45’43’’N, 29°29’39’’E, 50 m, mud, 1 specimen .

Additional material examined. Holotype, ESFM-POL/2010-16 , 15 April 2010, Sea of Marmara , 40°27’18’’N, 27°4’6’’E, 66 m, mud .

Description. All specimens incomplete, 6.6– 25 mm long, 0.13–0.20 mm wide, with 56–92 chaetigers. Color in alcohol usually pale yellowish. Body long, anterio-dorsal side strongly swollen, widths of prebranchial and branchial regions nearly same; getting gradually thinner from post branchial region to posterior end; with a black tube ( Fig. 5A ).

Prostomium conical, longer than wide (ratio length / width: 1.20); anterior part truncated with an eversible palpode; without eyes; with two annulations ( Fig. 5 A–B). A pair of nuchal organs placed as vertical lines on dorsolateral sides of posterior part of prostomium; without internal cilia; with two large brown spots on lateral sides of nuchal organs ( Fig. 5 A–B). Cilia patches and lateral organ absent. Cheek organ present on lateral sides of prostomium ( Fig. 6A ).

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; proboscis with lobes ( Figs 5B ; 6A ).

Branchiae 15–19 pairs, beginning on chaetiger 8 or 9, first and last pairs relatively short ( Figs 5A ; 6B ); cylindro-conical shaped, distal part with a round tip; dense ciliary bands present on both sides of outer margin of branchiae until middle region of branchiae; 320 µm long in anterior part, 408 µm long in middle part, 353 µm long in posterior part of branchial region. All branchiae fused to notopodia, merging degree decreasing from anterior to posterior part of branchial region ( Fig. 6 B–C)

Interramal lobes and notopodial papilla absent. Notopodial postchaetal lobes present, short and cirriform on first eight chaetigers (prebranchial region); thick and digitiform in branchial region, emerging on base of branchiae, with a rounded joint on tip; short, thick and with a rounded joint on tip in posterior chaetigers ( Fig. 6C, E ). Neuropodial postchaetal lobes and ventral lobes absent.

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 on chaetigers from middle to posterior part of branchial region, straight line-shaped with regularly clustered pores in posterior part of body ( Fig. 6 D–E); with 30–35 pores (length of lateral sense organ: 11–12 μm) in middle region, with 40–45 pores (length of lateral sense organ: 10–11 μm) in posterior region; with flexible cilia distinctly protruding from opening or embedded into pore.

Three types of chaetae present on chaetigers: limbate, capillary and modified neurochaetae.

Limbate chaetae present in notopodia from chaetiger 1 to chaetiger 8–15 and in neuropodia from chaetiger 1 to chaetiger 27–32, long, thin and straight with fibrils along edge (hirsute), positioning straight, colorless; in notopodia, numbering 7–15, arranged in two rows, ca. 192 µm; in neuropodia, numbering 10–20, arranged in two rows, ca. 211 µm.

Capillary chaetae starting in notopodia of chaetiger 9–16 and in neuropodia of chaetiger 28–33 to end of body, arranged as bundle, colorless ( Figs 6 B–C, E); in anterior notopodia, numbering 6–10 in each ramus and ca. 190 μm long; in posterior notopodia numbering 5–8 in each ramus and ca. 177 μm long in middle region and numbering 3–5 in each ramus and ca. 170 μm long; in middle neuropodia, numbering 8–10 in each ramus and ca. 232 μm long and in posterior neuropodia numbering 4–6 in each ramus and ca. 218 μm long.

Modified neuropodial chaetae present from chaetiger 26–32 to end of body; each neuropodium carrying 4–6 modified neurochaetae, arranged in one row, superior chaetae relatively straight and long, inferior chaetae much shorter and curved, about 40 μm long, thick, slightly curved, more or less sail-shaped hook, with a rudimentary, fibrillar hood on convex side ( Figs 5C ; 6E ).

Pygidium missing.

Reproduction. Eggs were found in some specimens of Levinsenia kosswigi collected from the Sea of Marmara. They usually first occurred at chaetiger 34 and continued to the posterior end and numbered six in each chaetiger. The egg diameter varied between 54 and 130 μm.

Remarks. The specimens of Levinsenia kosswigi from the present study are morphologically similar to the type specimens of the species collected from the Sea of Marmara, but some of our specimens have a larger body size (max. 15–16 mm in the type specimens vs. max. 25 mm in our specimens). Besides, the following characters were described for the first time in this study for Levinsenia kosswigi : cheek organ, notopodial postchaetal lobes with a rounded joint on tip, notopodium fused with the branchiae, lateral sense organs and limbate chaetae.

The fusion of the notopodium with the branchiae is herein described for the first time. It seems that this character is unique for this genus within Paraonidae and has not been observed in the other genera studied in the Sea of Marmara ( Erdoğan-Dereli et al. 2017; Erdoğan-Dereli & Çinar 2019; 2020a).

The cheek organ on the prostomium of Levinsenia species was first described as tubercles with cilia by Strelzov (1979). Later, this organ was proved not to be unique to Levinsenia and also described on the specimens of Paraonis fulgens from the Levantine Sea by Erdoğan-Dereli & Çinar (2020b) However, contrary to the Strelzov’s observation, this organ lacks cilia in all Levinsenia species found in the study area, except for L. materi ( Figs 6A ; 16B ; 17A ; 21 A–D).

Habitat Distribution. This species was found on soft substrata between 10 and 50 m in the Sea of Marmara. Çinar et al. (2011) previously reported this species in the same habitat at 66–70 m depth in the same region. This species also occurred in the Levantine Sea ( Çinar et al. 2014).

Figures

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.

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 16. Levinsenia longobranchiata n. sp. A, General view of body, holotype (ESFM-POL/2013-1030); B, Dorsal view of anterior part of body, with retractile cheek organ and palpode, stained with Shirlastain-A, paratype (ESFM-POL/2013-1043); C, Notopodial postchaetal lobe from chaetiger 8, paratype (ESFM-POL/2013-1043); D, Branchiae from middle part of branchial region, arrow pointing to unidentified parasites, stained with Shirlastain-A, paratype (ESFM-POL/2013-1043); E, Parapodium from a posterior chaetiger with notopodial postchaetal lobe and modified neurochaetae, paratype, (ESFM-POL/2013-1043); F, Modified neurochaeta from chaetiger 52, paratype (ESFM-POL/2013-1043); G, Modified neurochaetae from chaetiger 61, paratype (ESFM-POL/2013-1043). Scale bar: A, 500 µm; B, 90 µm; C, 25 µm; D, 60 µm; E, 30 µm; F, 12 µm; G, 18 µm. Ab- breviations: cho, cheek organ; ep, eversible palpode; ntpcl, notopodial postchaetal lobe.

FIGURE 17. Levinsenia longobranchiata n. sp. (paratype, ESFM-POL/2013-1043). A, Lateral view of prostomium and first chaetigers; B, First three chaetigers without notopodial postchaetal lobes; C, Middle branchial chaetiger, with notopodial post- chaetal lobe emerging on branchia; D, Branchia from middle branchial region, with notopodial postchaetal lobe. Scale bar: A, 42 µm; B, 80 µm; C, 38 µm; D, 35 µm. Abbreviations: bran, branchiae; cho, cheek organ; lso, lateral sense organ; no, nuchal organ; ntpcl, notopodial postchaetal lobe; sdcb, short dorsal ciliary band.

FIGURE 21. Levinsenia vulgaris n. sp. (ESFM-POL/2013-1181, paratype). A, Dorso-lateral side of prostomuim with a cheek organ; B, Cheek organ in retracted position; C, D, Lateral view of prostomuim with a cheek organ and nuchal organ. Scale bar: A, 79 µm; B, 7 µm; C, 70 µm; D, 23 µm. Abbreviations: cho, cheek organ; ep, eversible palpode; no, nuchal organ.