Aricidea (Acmira) cerrutii Laubier, 1966

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 : 19-23

Aricidea (Acmira) cerrutii Laubier, 1966

( Figures 10–12 )

Aricidea cerrutii Laubier 1967: 102–106 , fig. 1A– E.

Aricidea (Acesta) cerrutii: Strelzov 1979: 124–125 , fig. 45D–I.

Aricidea (Acmira) cerrutii: Aguirrezabalaga 2012: 171–175 , fig. 61A–D.

Material examined. ESFM-POL/2012-294 , 06 October 2012, station K3, 40°08’00’’N, 26°21’25’’E, 0–5m, Zostera marina Linnaeus , 2 specimens ; ESFM-POL/2013-1259 , 06 June 2013, station Y1, 40°01’08’’N, 26°13’00’’E, 50 m, mud, 1 specimen ; ESFM-POL/2013-1260 , 06 June 2013, station Y2, 40°06’59’’N, 26°22’04’’E, 50 m, muddy sand, 1 specimen ; ESFM-POL/2013-69 , 06 June 2013, station Y3, 40°12’03’’N, 26°26’21’’E, 10 m, mud with shell fragments, 12 specimens ; ESFM-POL/2013-84 , 07 June 2013, station Y4, 40°17’49’’N, 26°35’44’’E, 25 m, maerl bed, 1 specimen ; ESFM-POL/2013-89 , 07 June 2013, station Y5, 40°20’56’’N, 26°40’51’’E, 10 m, mud, 1 specimen ; ESFM-POL/2013-97 , 07 June 2013, station Y6, 40°26’10’’N, 26°41’51’’E, 10 m, mud, 1 specimen ; ESFM-POL/2013-1022 , 07 June 2013, station Y7, 40°26’10’’N, 26°41’51’’E, 10 m, sand, 27 specimens ; ESFM-POL/2013-1025, 07 June 2013, station Y7, 40°24’28’’N, 26°51’24’’E, 25 m, maerl bed, 2 specimens; ESFM-POL/2013-1027, 08 June 2013, station Y 9, 10 m, 40°26’20’’N, 27°11’32’’E, mud with gravel and shell fragments, 22 specimens; ESFM-POL/2013-1029 , June 2013, station Y10, 40°31’28’’N, 26°54’12’’E, 10 m, sand, 53 specimens ; ESFM-POL/2013-1307 , 10 June 2013, station Y13, 40°45’15’’N, 27°20’49’’E, 50 m, maerl bed, 1 specimen ; ESFM-POL/2013-1032 , 09 June 2013, station Y16, 40°18’35’’N, 27°45’46’’E, 10 m, fine sand, 10 specimens ; ESFM-POL/2013-1034 , 14 June 2013, station Y31, 40°01’44’’N, 28°26’31’’E, 10 m, sand, 6 specimens .

Description. Largest specimen complete, 16.80 mm, 0.54 mm wide, with 135 chaetigers. Color in alcohol usually light yellow; gamete bearing specimens with red speckles between notopodium and neuropodium along the body. Body thick and long; antero-dorsal side slightly swollen; anterior and middle region of similar width; posterior part of body thick and tapering to pygidium ( Fig. 10A ).

Prostomium subtriangular, wider than long (ratio length / width: 0.89); anterior margin rounded, with ciliated eversible palpode; eyes absent ( Figs 10B ; 11 A–D). Antenna thick, finger-like (antenna length / prostomium length: 0.30), in a central insertion; reaching up to chaetiger 1; with dense ciliation. Crown-like ciliary band (clcb) present, emerging from lateral sides of nuchal organs and surrounding prostomium ventrally ( Figs 10E ; 11B ). A long, dense transversal ciliary band (cb) present on dorsal side of prostomium, anterior to antenna; more or less M-shaped ( Figs 10F ; 11 B–E). A pair of nuchal organs present as deep, wide, long 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. 11C ). Mouth with three buccal lips; two placed anteriorly, one posteriorly and extending to anterior margin of chaetiger 1 with eight longitudinal folds.

A dense dorsal ciliary band (dcb) present on mid-dorsal transverse line of each prebranchial and branchial chaetiger. A pair of short dorsal ciliary bands (sdcb) present posterior to base of each branchia. An intersegmental ciliary band (iscb) present on dorsal side of chaetigers, originating from base of each notopodium ( Figs 11C ; 12A ). Ciliary bands absent on ventral side of body ( Fig. 11A ).

Branchiae 18 pairs, starting on chaetiger 4; thin, long, and cylindro-conical and slightly flattened in anterior region; becoming shorter in posterior region ( Figs 10A ; 11A ); 273 μm long in anterior region, 213 μm in middle region and 191 μm in posterior region.

Interramal lobes present as rudimentary ridges in branchial region ( Figs 10D ; 12A ). Notopodial papilla absent ( Figs 11A ; 12A ). Notopodial postchaetal lobes short and cirriform on first two chaetigers; long, thick and finger-like between chaetigers 3–20; thin, long and filiform on posterior chaetigers. Neuropodial postchaetal lobes absent ( Figs 11A ; 12A ). Ventral lobes absent.

Lateral sense organs present, elliptical with irregularly clustered pores in anterior and middle parts of branchial region; with 40–45 pores (long axis of lateral organ: 12–13 μm).

Three main types of chaetae present on chaetigers: limbate, capillary and modified neurochaetae. Limbate chaetae in both notopodia and neuropodia of chaetigers 1–13, long (but relatively shorter in neuropodium), thin and straight with fibrils along edge (hirsute) and colorless; in notopodia numbering 18–21, arranged in two rows, 295–360 µm long, ventral to dorsal in fascicle; in neuropodia numbering 16–18, arranged in three rows, 191–205 µm long, dorsal to ventral in fascicle ( Figs 11A ; Fig 12A ).

Capillary chaetae starting in noto- and neuropodia of chaetiger 14 and present on all subsequent chaetigers; in middle notopodia numbering 10–12, arranged in two rows, ca. 360 μm long; in posterior notopodia numbering 4–6, arranged in one row, ca. 204 μm long; in middle neuropodia numbering 14–16, arranged in two rows, ca. 286 μm long; in posterior neuropodia numbering 2–5, arranged in one row, ca. 250 μm long.

Modified neurochaetae present from chaetigers 26–35 to pygidium, numbering 5–8 in each neuropodium; length of modified chaeta (about 82 μm) almost identical in body regions; hook-shaped, subterminal region strongly curved; with a distinct “hood”, pubescence present in subterminal region ( Figs 10C ; 12 B–D).

Pygidium flattened, almost rounded, with 3 anal cirri; two asymmetrical digitiform cirri placed ventro-laterally (short one, digitiform, 50 μm long, long one, 151 μm long); and one thick cirrus placed mid-ventrally (43 μm long) ( Fig. 10G ).

Reproduction. Some specimens of A. cerrutii from the Sea of Marmara had eggs in their coelomic cavities. They were generally present from chaetigers 30–36 to posterior end, numbering two in each chaetiger, and had a diameter of 150–170 μm ( Fig. 12E ). The gamete bearing specimens had red speckles between notopodia and neuropodia.

Remarks. The specimens of A. cerrutii from the Sea of Marmara are similar to the previous descriptions of the species ( Laubier 1967; Strelzov 1979; Hartmann-Schröder 1996; Aguirrezabalaga 2012) in terms of body size, branchiae number, modified neurochaeta and antenna.

The crown-like ciliary band (clcb) and ciliary band (cb) on the prostomium are herein described for the first time. The ciliary band (cb) is more or less M-shaped and very thick in A. cerrutii . Among the Aricidea species found in the present study, only A. simonae has such a band but it is relatively thin. However, unlike the rest of species, these two do not have ciliary slit (cs) on the prostomium. It would be an interesting subject to investigate if these two ciliary organs are homologous. The M-shaped ciliary band (cb) was also present in Paradoneis kamaehu Magalhães, Bailey-Brock & Barroso, 2019 and Paradoneis yucatanensis Quintanar-Retama, Hernández-Alcántara & Solís-Weiss, 2019 ( Magalhães et al. 2019; Quintanar-Retama et al. 2019).

Aricidea cerrutii has interramal lobes on parapodia in the branchial region that were not described before for this species. Although not mentioned, it was apparent on figures of Aricidea (Acmira) simplex Day, 1963 ; A. (Acmira) horikoshii Imajima, 1973 ; A. (Acmira) mirifica Strelzov, 1973 ; A. (Acmira) neosuecica nipponica Imajima, 1973 ; A. (Acmira) philbinae Brown, 1976 ; A. (Acmira) punctata Hartmann-Schröder, 1962 ; A. (Acmira) rubra Blake, 1996 ; A. (Strelzovia) antennata Annenkova, 1934 ; A. (Strelzovia) belgicae ( Fauvel, 1936) ; A. (Strelzovia) bryani Gaston & McLelland, 1996 ; A. (Strelzovia) curviseta Day, 1963 ; A. (Strelzovia) hartleyi Blake, 1996 ; A. (Strelzovia) quadrilobata Webster & Benedict, 1887 and A. (Strelzovia) suecica Eliason, 1920 ( Hartmann-Schröder 1962; Day 1967; Imajima 1973; Strelzov 1979; Brown 1976; Blake 1996; Gaston & McLelland 1996; Hartmann-Schröder 1996).

Habitat and Distribution. The specimens of A. cerrutii were found in sandy-muddy bottoms and Zostera marina habitat at depths ranging from 1 to 50 m in the Sea of Marmara. It was previously reported on similar habitats and Posidonia oceanica biotope between 2 and 531 m depths in the eastern Atlantic Ocean ( Aguirrezabalaga 2012), and eastern ( Çinar et al. 2014) and western ( Laubier 1967; Katzmann & Laubier 1975) Mediterranean.

Figures

FIGURE 10. Aricidea (Acmira) cerrutii. A, General view of body (ESFM-POL/2013-1034); B, Lateral view of anterior end, stained with Shirlastain-A (ESFM-POL/2013-1034); C, Modified neurochaeta on chaetiger 104 (ESFM-POL/2013-1034); D, Cross section of chaetiger 8 (ESFM-POL/2013-1029); E, Dorsal view of half prostomium (ESFM-POL/2013-1029); F, Anterolateral view of prostomium (ESFM-POL/2013-1029); G, Lateral view of pygidium (ESFM-POL/2013-1034). Abbreviations: cb; ciliary band; clcb; crown-like ciliary band; irl, interramal lobe; ntpcl, notopodial postchaetal lobe. Scale bar:A, 1506 µm; B, 183 µm; C, 14 µm; D, 102 µm; E, 36 µm; F, 32 µm; G, 117 µm.

FIGURE 11. Aricidea (Acmira) cerrutii (ESFM-POL/2013-1029). A, Lateral view of anterior part of body; B, Lateral view of prostomuim; C, Dorsal view of prostomium and first chaetiger; D, Dorsal view of prostomium and first chaetiger; E, Anterior part of prostomium, arrows pointing the ridges. Abbreviations: ant, antenna; clcb, crown-like ciliary band; cb, ciliary band; dcb, dorsal ciliary band; ep, eversible palpode; no, nuchal organ. Scale bar: A, 136 µm; B, 31 µm; C, 36 µm; D, 58 µm; E, 28 µm.

FIGURE 12. Aricidea (Acmira) cerrutii (ESFM-POL/2013-1029). A, Lateral view of chaetigers 7, 8 and 9; B, Lateral view of modified neurochaeta with strong hood of posterior chaetiger; C, Modified neurochaetae with strong hood of posterior chaetiger; D, Modified neurochaeta on posterior chaetiger; E, Egg in posterior chaetiger. Abbreviations: bran, branchia; dcb, dorsal ciliary band; irl, interramal lobe; iscb, intersegmental ciliary band; lso, lateral sense organ; ntpcl, notopodial postchaetal lobe; sdcb, short dorsal ciliary band. Scale bar: A, 31 µm; B, 3 µm; C, 7 µm; D, 6 µm; E, 80 µm.