Aricidea (Aricidea) bansei Laubier & Ramos, 1974

Erdoğan-Dereli, Deniz & Çinar, Melih Ertan, 2020, The diversity of the genus Aricidea (Polychaeta: Paraonidae) from the Sea of Marmara, with descriptions of two new species and two new records for the Mediterranean fauna, Zootaxa 4844 (1), pp. 1-73 : 48-52

Aricidea (Aricidea) bansei Laubier & Ramos, 1974 new status

( Figures 33–35 )

Aricidea capensis bansei Laubier & Ramos 1974: 1109–1112 , fig. 5; Aguirrezabalaga 2012: 222–223, figs. 93, 94

Material examined. ESFM-POL/1997-496 , 22 October 1997, Sea of Marmara, Çanakkale, Kepez , 40°6’20”N, 26°22’39”E, 25 m, sandy mud, 1 specimen .

Additional material examined. ESFM-POL/2017-152 , 5 August 2017, Levantine Sea, off Üçağız Kaleköy , 36° 9’ 26” N, 29° 46’ 49” E, 22 m, Posidonia oceanica , 3 specimens ; ESFM-POL/2017-153 , 10 October 2017, Aegean Sea, Izmir Bay, off Karaburun , 38°36’34” N, 26°34’59” E, 61.5 m, sandy mud, 1 specimen .

Description. Largest specimen complete, 12.92 mm long, 0.44 mm wide at chaetiger 10, with 52 chaetigers. Color in alcohol yellowish, anterior chaetigers reddish ( Fig. 33A ). Body cylindrical and thin; widths of prebranchial and branchial regions nearly same, becoming thinner on posterior region ( Fig. 33A ).

Prostomium subtriangular; much longer than wide (ratio length/width: 1.08), anterior margin rounded, with two intradermal eyes. Crown like ciliary band (clcb) and a pair of ciliary slits (cs) present ( Fig. 34 B–C). Antenna inserted on mid-region of prostomium, long, with 4 annulations, extending to anterior margin of chaetiger 3 ( Figs 33B ; 34B ). A pair of nuchal organs each wide, deep, short, slanted slits placed on dorso-lateral sides of posterior prostomium, more or less convex in shape; dense internal ciliation present, cilia reaching outer margin of slits; without pigmentation ( Fig. 34 C–D). Mouth with three buccal lips; two placed anteriorly, one placed posteriorly and extending to anterior margin of chaetiger 1, with eight longitudinal folds; a Y-shaped gap present between anterior lips.

A dense dorsal ciliary band (dcb) present on mid-dorsal transversal line of each prebranchial and branchial chaetigers. A pair of short dorsal ciliary bands (sdcb) present just posterior to each branchial base ( Figs 34B ; 35A ). Ciliary bands absent on ventral side of body.

Branchiae numbering nine pairs, starting in chaetiger 4, narrow, cylindro-conical; first and last pair short; branchiae always shorter than segment width, becoming longer posteriorly, not elongated ( Figs 33 A–B; 34A; 35B); 101 μm long in anterior region, 105 μm long in middle region, 128 μm long in posterior region; ciliary bands present on both sides of branchiae, lined up to form ellipse shapes, arranged in one row, only covering a line from base to middle region of branchiae ( Fig. 35A, B ).

Interramal lobes and notopodial papilla absent ( Fig. 35 A–B, D). Notopodial postchaetal lobes starting on chaetiger 1; short, cirriform on first two chaetigers; extremely long (three times longer than those in chaetiger 2; 1.2 times longer than those in chaetiger 4) and bottle-shaped in chaetiger 3; stout, long, digitiform in branchial region; long, filiform and weakly jointed in postbranchial region ( Figs 34 A–B; 35A–C). Neuropodial postchaetal lobes absent ( Fig. 35D ). Ventral lobes present in chaetigers 3–9.

Lateral sense organs present on all chaetigers, located between notopodia and neuropodia, posterior to notopodial postchaetal lobes, except for branchial region where lateral sense organ are located at base of notopodial postchaetal lobes; with flexible cilia distinctly protruding from opening or embedded into pore ( Fig. 35 A–D); oval-shaped with irregularly clustered pores in prebranchial and branchial regions; straight line-shaped with regularly clustered pores in postbranchial region; with 9–12 pores in prebranchial region (long axis of organ: ca. 5–6 μm), with 20–22 pores (long axis: 5–6 μm) in branchial region, with 20–28 pores (long axis: 8–11 μm) in posterior region.

Three types of chaetae present on chaetigers: limbate, capillary and modified neurochaetae. Limbate chaetae of two types; first type present only in notopodia of chaetigers 1–10, numbering 6–10, arranged in two rows, ca. 204 μm long, thin, long and straight with fibrils along edge (hirsute), ventral to dorsal in fascicle, colorless; second type only present in neuropodia of chaetigers 1–10, numbering 9–16, arranged in two rows, ca. 184 μm long, much wider and relatively short, in sigmoid shape with fibrils along edge (hirsute), dorsal to ventral in fascicle, colorless ( Figs 34 A–B; 35B, D).

Capillary chaetae starting in noto- and neuropodia of chaetiger 11 and present in all subsequent chaetigers; in middle notopodia arranged in one row, numbering 7–10, ca. 177 μm long; in posterior notopodia numbering 5–8, ca. 170 μm long; in middle neuropodia numbering 6–8, ca. 245 μm long; in posterior neuropodia numbering 8–10, ca. 241 μm long.

Modified neurochaetae starting in chaetigers 24–31, two types; first type numbering 4–6 in each neuropodium, long (average length: 30 μm, without arista), as curved hooks with a strong hood, subdistal part minutely dentated, pubescence on terminal region, with a long and stout arista arising from concave side of tip; second type numbering 1 in each neuropodium, relatively long, becoming thinner towards distal end, with a pointed tip slightly bending towards concave side, with a very long and strong arista arising from concave side of tip ( Figs 33 C–E; 35E–G).

Pygidium small and rounded, with three cirri ( Fig. 33F ); two cirri placed on dorsal side (long, digitiform, 37 μm long); one cirrus placed on ventral side (short, digitiform, 13 μm long).

Remarks. The subspecies Aricidea capensis bansei is raised to the species level, A. bansei n. stat., because of the following reasons: (1) the notopodial postchaetal lobes on chaetiger 3 are extremely enlarged and bottle shaped in A. bansei n. stat., whereas they are small and cirriform in A. capensis ; (2) two types of modified neurochaetae are present in A. bansei n. stat., whereas only one type of modified neurochaeta is present in A. capensis ; (3) branchiae are usually 8–10 pairs in A. bansei n. stat., whereas there are 14 pairs of branchiae in A. capensis .

In the original description of A. bansei by Laubier & Ramos (1974), the second type of modified neurochaeta was not mentioned. Although photographed by Aguirrezabalaga (2012: Fig. 94C), this type of chaeta has been overlooked on the species so far. The notopodial postchaetal lobes in chaetiger 3 have an exceptionally unique shape and relatively stout in A. bansei . Among paraonids, only Paradoneis heterochaeta Erdoğan-Dereli & Çinar, 2019 also has relatively stout notopodial postchaetal lobes on chaetiger 3 ( Erdoğan-Dereli & Çinar 2019).

The other distinctive character of A. bansei is the presence of elliptical clusters of cilia forming a straight line from the base to the middle region of the branchiae ( Fig. 35 A–B), whereas other species examined here have cilia arranged in a row (like band) from the base to the subdistal part (the point where the branchia is abrubtly tapered) of the branchiae ( Figs 3B ; 6 A–B; 8A; 21A–C; 26B; 31A; 37B; 41A–B; 44A; 46C).

Habitat and Distribution. This species was found in soft substrata at 25 m depths in the Sea of Marmara and in soft substrata and Posidonia oceanica biotope at depths 22–62 m in the Aegean Sea. According to the previous studies, this species was reported from similar habitats between 5 and 40 m depths in the Atlantic Ocean ( Gil & Sarda 1999; Aguirrezabalaga 2012), and the western ( Laubier & Ramos 1974; Castelli 1988) and eastern ( Çinar et al. 2014) Mediterranean Seas.

Figures

FIGURE 3. Aricidea (Acmira) annae (ESFM-POL/2017-151).A, Antero-dorsal view of body; B, Branchiae; C, Posterio-dorsal view of prostomium; D, Nuchal organ. Abbreviations: a, annulation; cs, ciliary slits; clcb, crown-like ciliary band; dcb, dorsal ciliary band; no, nuchal organ; pro, prostomium; sdcb, short dorsal ciliary band. Scale bar: A, 218 µm; B, 140 µm; C, 37 µm; D, 11 µm.

FIGURE 6. Aricidea (Acmira) assimilis (ESFM-POL/2013-1221). A, Antero-dorsal view of body; B, Anterio-dorsal view of anterior end; C, Dorsal view of branchial region, short dorsal ciliary bands; D, Dorsal view of half of prostomium.Abbreviations: cs, ciliary slit; clcb, crown-like ciliary band; dcb, dorsal ciliary band; no, nuchal organ; sdcb, short dorsal ciliary band. Scale bar: A, 579 µm; B, 193 µm; C, 300 µm; D, 101 µm.

FIGURE 33. Aricidea (Aricidea) bansei n. stat. (ESFM-POL/1997-496). A, General view of body; B, Dorso-lateral view of anterior end; C, Modified neurochaetae on posterior chaetiger; D, Capillary and modified neurochaetae of posteiror chaetiger; E, Modified neurochaetae on posterior chaetiger; F, Lateral view of pygidium. Scale bar: A, 368 µm; B, 155 µm; C, 30 µm; D, 36 µm; E, 27 µm; F, 42 µm.

FIGURE 34. Aricidea (Aricidea) bansei n. stat. (ESFM-POL/2017-152). A, Dorsal view of anterior end; B, Dorsal view of anterior end; C, Dorsal view of right half of prostomium; D, Nuchal organ. Abbreviations: bran, branchia; clcb, crown-like ciliary band; cs, ciliary slits; dcb, dorsal ciliary band; ntpcl, notopodial postchaetal lobe; no, nuchal organ. Scale bar:A, 246 µm; B, 127 µm; C, 35 µm; D, 12 µm.

FIGURE 35. Aricidea (Aricidea) bansei n. stat. (ESFM-POL/2017-153). A, Lateral view of posterior branchial chaetiger, arrows pointing elliptical clusters of cilia forming in straight line; B, Lateral view of posterior branchial chaetigers, arrows pointing elliptical clusters of cilia forming in straight line; C, Notopodium of posterior chaetiger; D, Parapodia of anterior chaetigers, limbate chaetae; E, Modified neurochaetae of posterior chaetiger with type I and type II; F, Modified neurochaetae of posterior chaetiger; G, Modified neurochaeta of posterior chaetiger.Abbreviations: bran, branchia; neu, neurpodium; neupcl, neuropodial postchaetal lobe; not, notopdium; ntpcl, notopodial postchaetal lobe; lso, lateral sense organ; sdcb, seconder dorsal ciliary band. Scale bar: A, 23 µm; B, 28 µm; C, 5 µm; D, 25 µm; E, 14 µm; F, 15 µm; G, 5 µm.