Leitoscoloplos mediterranea, Çinar & Dağli & Erdoğan-Dereli, 2022

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 : 1400-1407

Leitoscoloplos mediterranea sp. nov.

( Figures 7–10 )

Type material

Levantine Sea, Turkey, holotype. ESFM –POL/2018–156, 09 August 2018, Levantine Sea, DALSW2 , 36.702222°N, 28.732247°E, 45 m, fine sandy mud .

Paratypes. ESFM –POL/2018–156, 09 August 2018, Levantine Sea, DALSW2 , 36.702222°N, 28.732247°E, 45 m, fine sandy mud, 12 specimens; ESFM –POL/2016–248, 14 July 2016, Iskenderun Bay , near Bakü-Tbilisi-Ceyhan Oil Terminal , 36.840833°N, 35.908889°E, 13 m, sandy mud, 1 specimen; ESFM –POL/2015–657, 02 July 2015, Iskenderun Bay , near BaküTbilisi-Ceyhan Oil Terminal , 36.869444°N, 35.919722°E, 5 m, sandy mud, 2 specimens; ESFM –POL/2015–656, 02 July 2015, Iskenderun Bay, near Bakü-Tbilisi-Ceyhan Oil Terminal, 36.864444°N, 35.924444°E, 8.6 m, sandy mud, 6 specimens .

Non-type material

Aegean Sea, Turkey. ESFM –POL/2014–148, 21 Apr’l 2014, off Akköy , 37.440556°N, 27.123333°E, 65 m, mud, 12 specimens; ESFM –POL/2014–285, 24 July 2014, off Akköy, 37.461667°N, 27.122500°E, 66 m, sandy mud, 58 specimens; ESFM –POL/2014–449, 26 Ocober 2014, off Akköy, 37.461667°N, 27.122500°E, 66 m, sandy mud, 2 specimens; ESFM –POL/2014–488, 27 October 2014, off Güllük, 37.167500°N, 27.466667°E, 46 m, sandy mud, 4 specimens; ESFM –POL/2015–303, 30 August 2015, Marmaris Bay , 36.843889°N, 28.271667°E, 15 m, sandy mud with shell fragments, 19 specimens; ESFMPOL/2015–304, 18 August 2015, Güllük, 37.125000°N, 27.508056°E, 48 m, sandy mud, 8 specimens; ESFM –POL/2014–654, 24 July 2014, off Akköy, 37.466667°N, 27.122778°E, 66 m, mud, 69 specimens; ESFM –POL/2015–306, 17 August 2015, off Küçük Menderes River mouth, 37.949444°N, 27.259722°E, 35 m, mud, 2 specimens; ESFM –POL/2017–204, 01 May 2017, Gökova Bay, 36.791800°N, 27.750970°E, 49 m, sandy mud with shell fragments, 23 specimens .

Description

Holotype complete, 11.6 mm long, 0.5 mm wide across thoracic segments and 1.45 mm across middle segments for about 63 chaetigers; paratypes complete, up to 15 mm long and 0.95 mm wide across thoracic segments for approximately 75 chaetigers. Anterior part flattened dorsoventrally, gradually tapering to posterior end. Colour in alcohol opaque white.

Prostomium conical, sharply pointed ( Figures 7 (a–c), 9(a–c)); nuchal organs short oval slits on posterior lateral margin ( Figures 7 (a,c), 9(a,b)), eyespots absent. Peristomium with one achaetous ring ( Figures 7 (a,b), 9(a,b)). Proboscis everted in some paratypes, rounded ( Figure 7 (c)); mouth with 6 lobes ( Figure 9 (c)).

Thoracic region with 10–11 chaetigers. Notopodial postsetal lobe triangular on chaetiger 1; digitiform on following chaetigers, increasing in size along thorax ( Figures 7 (b,c), 8 (c)). Neuropodial postsetal lobe on chaetiger 1 small and digitiform; mammiliform on following chaetigers; subpodal flange distinct. Ventral cirri noticable after chaetiger 10 ( Figures 7 (b), 10(d)); subpodial lobe/papilla rounded, from chaetigers 9 to 15 ( Figures 7 (b), 10(d)). Without subpodal notch. Interramal cirrus absent. Abdominal neuropodia distally bilobed, cylindrical; both lobes short and blunt, but outer lobe broader and slightly longer than inner lobe; more posteriorly both lobes of similar length; without subpodal papilla ( Figures 8 (a,b), 10(a,b)); subpodial flange distinct, truncated ( Figures 8 (b), 10(d)).

All thoracic and abdominal noto- and neurochaetae crenulated capillaries; with crenulations consisting of numerous transverse rows of barbs ( Figures 8 (d), 10(b,c)). Thoracic capillaries (noto- and neurosetae) numbering up to 25–29, placed in two rows; abdominal noto- and neurosetae numbering 3–7 capillaries. Furcate and flail chaetae absent.

Branchiae present from chaetiger 12, on first abdominal chaetiger; first five pairs small, papilliform, gradually increasing in size towards posterior part; becoming broad, with lateral lobes on middle abdominal chaetigers; rectangular and up to twice width of notopodial lamellae on posterior chaetigers ( Figures 8 (a,b), 10(a,b)). Lateral margins densely ciliated ( Figures 8 (b), 10(a)).

Pygidium bluntly rounded, with terminal anus, bearing two thin elongate anal cirri ( Figures 7 (d), 9(d)).

Remarks

According to the classification of the Leitoscoloplos species by Blake (2017), based on the presence and absence, and the first appearance, of branchiae along the body, Leitoscoloplos mediterranea sp. nov. falls into group D (the L. kerguelensis group), which includes 15 valid species, namely L. bilobatus Mackie, 1987 ; L. eltaninae Blake, 2017 ; L. geminus Mackie, 1987 ; L. kerguelensis (McIntosh, 1885) ; L. latibranchus Day, 1977 ; L. mawsoni (Benham, 1921) ; L. nasus Blake, 2017 ; L. pachybranchiatus Blake and Hilbig, 1990 ; L. phyllobranchus Blake, 2017 ; L. rankini Blake, 2017 ; L. plataensis Blake, 2017 ; L. cliffordi Blake, 2020 ; L. gordaensis Blake, 2020 ; L. lunulus Blake, 2020 ; and L. williamsae Blake, 2020 . The L. kerguelensis group is characterised by having branchiae first appearing from the anterior abdominal chaetigers; no eyespots; crenulated capillary chaetae on thoracic noto- and neuropodia; nuchal organs (except for L. phyllobranchus ); no interramal cirrus, stomach papillae and subpodal notch. Seven of these species, namely L. eltaninae , L. pachybranchiatus , L. rankini , L. cliffordi , L. gordaensis , L. lunulus and L. williamsae , have been found only in the deep sea (deeper than 1000 metres), and seven species, namely L. bilobatus , L. geminus , L. mawsoni , L. nasus , L. phyllobranchus , L. plataensis and L. latibranchus , have been found only in shallow waters, and one species ( L. kerguelensis ) has been found in both deep and shallow waters.

Leitoscoloplos mediterranea sp. nov. is mainly characterised by having a sharply pointed prostomium; mammiliform thoracic neuropodial postsetal lobes; 10–11 thoracic chaetigers; branchiae first emerging on chaetiger 12; subpodal papillae on chaetigers 9 to 15; bilobed abdominal neuropodia; no furcate chaeta; well developed subpodal flanges; and bluntly rounded pygidium with two thin elongate cirri. Among the L. kerguelensis group, the species that, like L. mediterranea sp. nov., do not have furcate chaetae are L. gordaensis , L. latibranchus , L. lunulus , L. pachybranchiatus and L. williamsae . However, L. mediterranea sp. nov. differs from these species in terms of the following characters: (1) the shape of the prostomium (conical, sharply pointed in L. mediterranea sp. nov. vs short, bluntly conical in L. latibranchus ; conical, smoothly rounded on anterior margin in L. pachybranchiatus ; triangular, short in L. gordaensis ; semi-circular, narrowing to broadly rounded apex in L. lunulus ; and conical, tapering to narrow apex in L. williamsae ); (2) the number of thoracic chaetigers (10–11 chaetigers in L. mediterranea sp. nov. vs 15–16 chaetigers in L. latibranchus ; nine chaetigers in L. pachybranchiatus and L. williamsae ; 10–12 chaetigers in L. gordaensis ; and 14–15 chaetigers in L. lunulus ); (3) the first appearance of the branchiae (on chaetiger 12 in L. mediterranea sp. nov. vs on chaetigers 19–22 in L. latibranchus ; on chaetigers 13–15 in L. pachybranchiatus ; on chaetigers 14–16 in L. gordaensis ; on chaetigers 14–15 in L. lunulus ; and on 17–18 chaetigers in L. williamsae ); (4) the presence of the subpodal papillae (present on chaetigers 9–15 in L. mediterranea sp. nov. vs absent in L. latibranchus , L. pachybranchiatus , L. gordaensis , L. lunulus and L. williamsae ); and (5) the morphology of the subpodial flange (truncated in L. mediterranea sp. nov. vs somewhat rounded in L. lunulus ; bulbous in L. williamsae ; absent in L. gordaensis , L. pachybranchiatus and L. latibranchus ).

The only species of the genus that had so far been reported from the Mediterranean Sea is L. kerguelensis . Leitoscoloplos mediterranea sp. nov. mainly differs from this species in lacking the furcate chaetae (present in L. kerguelensis ). The other morphological differences are (1) the number of thoracic chaetigers (10– 11 in L. mediterranea sp. nov. vs 9 in L. kerguelensis ); (2) the number of branchiae (12 pairs in L. mediterranea sp. nov. vs 13–14 pairs branchiae in L. kerguelensis ); (3) the presence of the subpodal papillae (present in L. mediterranea sp. nov. vs absent in L. kerguelensis ); (4) the morphology of subpodal flange (distinct, long in L. mediterranea sp. nov. vs short, narrow in L. kerguelensis ); (5) the presence of forked chaeta (not present in L. mediterranea sp. nov. vs present in L. kerguelensis ); and (6) the shape of the pygidium (with two thin anal cirri in L. mediterranea sp. nov. vs without anal cirri in L. kerguelensis .

Reproduction

The specimens of L. mediterranea sp. nov. collected in August have four eggs in each coelomic cavity between chaetigers 14 and 19; egg diameters are between 174 and 191 μm.

Etymology

The species name refers to the geographical area of its distribution.

Distribution

The new species is only known from the Levantine and Aegean coasts of Turkey (eastern Mediterranean). However, the previous records of L. kerguelensis from the Mediterranean Sea ( Desbruyères et al. 1973; Ramos 1976; Faulwetter et al. 2017) should be examined to determine whether the specimens in fact belong to L. mediterranea sp. nov. Leitoscoloplos kerguelensis was originally described from Antarctica and has been recorded from different locations worldwide. The present article and other newly published papers (e.g. Blake 2017) indicate that the accuracy of these records may be doubtful and needs confirmation. The presence of L. kerguelensis was previously questioned in the Mediterranean Sea by Mackie (1987) and Blake (2017).

Figures

Figure 7. Leitoscoloplos mediterranea sp. nov. paratype (ESFM-POL/2014-285): (a) anterior end, dorsal view; (b) anterior end, lateral view; (c) anterior end, lateral view with proboscis everted; (d) posterior end, dorso-lateral view. Scale bar: a = 0.5 mm; b = 0.63 mm; c = 0.42 mm; d = 0.27 mm. Abbreviations. aC: anal cirrus; an: anus; Crcap: crenulated capillaries; mo: mouth; neP: neuropodium; nePsl: neuropodial postchaetal lobe; noPsl: notopodial postchaetal lobe; nuO: nuchal organ; per: peristomium; pr: prostomium; prob: proboscis; sp: subpodial papillae; sPod flange: subpodial flange.

Figure 8. Leitoscoloplos mediterranea sp. nov. paratypes: (a) anterior abdominal segment, cross section, anterior view (ESFM–POL/2015–304); (b) posterior abdominal parapodium, anterior view (ESFM–POL/2017–204); (c) thoracic parapodium, anterior view (ESFM–POL/2017–204); (d) crenulated capillary chaetae (a: in thoracic region; b: in anterior abdominal region; c: in posterior abdominal region). Scale bar: a = 0.5 mm; b = 0.36 mm; c = 0.45 mm; d(a) = 18 µm; d(b) = 14 µm; d(c) = 20 µm. Abbreviations. br: branchia; brc: branchial ciliae; br w/Lat lobe: branchia with a lateral lobe; Crcap: crenulated capillaries; neP: neuropodium; nePsL: neuropodial postchaetal lobe; neS: neuropodial chaeta; noPsL: notopodial postchaetal lobe; noS: notopodial chaeta; sPod flange: subpodial flange.

Figure 9. Leitoscoloplos mediterranea sp. nov. paratype (ESFM–POL/2018–156): (a) anterior end, dorso–lateral view; (b) anterior end, dorsal view; (c) anterior end, ventral view; (d) posterior end, pygidium, terminal view. Scale bar: a = 50 µm; b = 61 µm; c = 75 µm; d = 93 µm. Abbreviations. aC: anal cirrus; an: anus; mo: mouth; mOL: mouth lobes; nuO: nuchal organ; per: peristomium; pr: prostomium.

Figure 10. Leitoscoloplos mediterranea sp. nov. paratype (ESFM–POL/2014–488): (a) abdominal parapodium, dorso-lateral view; (b) abdominal parapodium, lateral view; (c) thoracic chaetigers, lateral view; (d) middle abdominal chaetigers, lateral view. Scale bar: a = 200 µm; b = 75 µm; c = 101 µm; d = 217 µm. Abbreviations. br: branchia; brc: branchial ciliae; Crcap: crenulated capillaries; neP: neuropodium; nePsL: neuropodial postchaetal lobe; noPsL: notopodial postchaetal lobe; sp: subpodial papillae; sPod flange: subpodial flange; vC: ventral cirrus.