Aricidea (Strelzovia) mirunekoa Aguirrezabalaga & Gil 2009
- Dataset
- 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
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Annelida
- class
- Polychaeta
- order
- Spionida
- family
- Paraonidae
- genus
- Aricidea
- species
- Aricidea mirunekoa
description
(Figures 47 – 49)
description
Description. Largest specimen incomplete, 4.95 mm long, 0.50 mm wide, with 33 chaetigers. Color in alcohol white. Body stout and wide in anterior part of body; gradually becoming slender towards posterior segments (Fig. 47 A). Prostomium subtriangular, without annulations, much wider than long (ratio length / width: 0.82), anterior margin rounded, without eyes (Figs 47 A – B; 48 C). Crown like ciliary band (clcb) present, ciliary slits (cs) absent (Fig. 48 A – C). Antenna short and bottle-shaped, with a rounded tip (ratio antenna length / prostomium length: 0.30) and central insertion, reaching end of prostomium (Figs 47 B; 48 A, C). A pair of nuchal organs as wide and deep short slits placed on dorso-lateral sides of posterior prostomium, more or less convex in shape; dense internal ciliation present, cilia not reaching outer margin of slits; without pigmentation; a pair of ridges located inner side of nuchal slits (Figs 47 B; 48 A, C). Mouth with four lips; two placed anteriorly and two placed posteriorly and extending to anterior margin of chaetiger 1 (Figs 47 C – D; 48 D). 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 (Fig. 48 B). Ciliary bands absent on ventral side of body (Fig. 48 D). A short swelling (ss) present on mid-dorsal side of chaetigers in prebranchial (except for chaetiger 1) and branchial regions; a pair of weakly developed skin folds (sf) located on dorso-lateral sides of each chaetiger in pre- and branchial regions (Figs 47 A, E; 48 B). Branchiae 19 pairs, starting in chaetiger 4. Branchiae flattened and tapering; becoming longer with elongated pointed tips in posterior branchial region (Figs 47 A, E; 48 B); approximately 344 μm long in anterior region, 538 μm long in middle region and 570 μm long in posterior region. Notopodial postchaetal lobes present, short and cirriform in first chaetiger; becoming long and digitiform with an asymmetrical swelling on base from chaetiger 2 to middle part of branchial chaetigers; long and digitiform, without any swelling basally, from middle part to posterior part of branchial chaetigers; thin and filiform in posterior chaetigers (Figs 47 B, E – G; 48 A – B; 49 A, C – D). Neuropodial lobes small, only present in first 11 chaetigers. Ventral lobe present on chaetigers 3 – 18, rounded (Figs 48 D; 49 B). Notopodial papillae absent. Three types of chaetae present on chaetigers: limbate, capillary and modified neurochaetae. Limbate chaeta of two types; first type present in notopodia of chaetigers 1 – 15, numbering 18 – 20, arranged in three rows, ca. 286 µm long, thin and straight with fibrils along edge (hirsute), directed posterio-dorsal side, light rose colored; second type present in neuropodia of chaetigers 1 – 15, numbering 25 – 30, arranged in five rows, ca. 237 µm long, much wider and sigmoid with fibrils along edge (hirsute), directed posterio-ventral side, light rose-colored (Fig. 49 A – D). Capillary chaetae starting in noto- and neuropodia of chaetiger 16 and present on all subsequent chaetigers; in middle notopodia numbering 13 – 20, arranged in 2 – 3 rows, ca. 360 μm long; in posterior notopodia numbering 5 – 6, arranged in one row, 223 μm long; in middle neuropodia numbering 15 – 20, arranged in two rows, 231 μm long; in posterior neuropodia numbering 6 – 10, arranged in one row, 218 μm long. Two types of modified neuropodial chaetae present, from chaetigers 23 – 31 to posterior end; each neuropodium bearing 2 – 3 modified chaetae; gradation in lenght from short inferior to long superior (Fig. 47 G); first type Strelzoviatype, very long (average length: 115 µm), becoming gradually thinner with numerous fibrils on convex side; second type like Strelzovia - type relatively short (average length: 88 µm), becoming abruptly thinner, with numerous fibrils on convex side (Figs 47 G – H; 48 E). Pygidium missing.
discussion
Remarks. The morphology of the specimens of Aricidea mirunekoa from the Sea of Marmara resembles the original description of the species by Aguirrezabalaga & Gil (2009). Aricidea mirunekoa is most similar to A. mariannae, which is also a deep-water Mediterranean species (Katzmann & Laubier 1975). The only difference between these two species is the length of the notopodial lobe on chaetigers 2 and 3; with longer lobes in chaetiger 2 in A. mirunekoa and longer ones in chaetiger 3 in A. mariannae. Habitat and Distribution. Aricidea mirunekoa is a deep-sea species, found on muddy bottoms at 500 – 1100 m depths in the Sea of Marmara. It is a new species for the Mediterranean fauna. According to Aguirrezabalaga & Gil (2009), this species was collected from similar habitats and between 480 and 968 m depth in northeast Atlantic Ocean.
materials_examined
Material examined. ESFM-POL / 2013 - 1002, 10 June 2013, station Y 13, 40 ° 46 ’ 23 ’’ N, 27 ° 23 ’ 43 ’’ E, 500 m, mud, 1 specimen; ESFM-POL / 2013 - 637, 11 June 2013, station Y 18, 40 ° 59 ’ 52 ’’ N, 27 ° 41 ’ 59 ’’ E, 1000 m, mud with shell fragmetns, 15 specimens; ESFM-POL / 2013 - 1005, 15 June 2013, station Y 21, 40 ° 45 ’ 24 ’’ N, 27 ° 58 ’ 12 ’’ E, 1100 m, mud, 12 specimens; ESFM-POL / 2013 - 1004, 23 June 2013, station Y 32, 40 ° 53 ’ 32 ’’ N, 28 ° 34 ’ 16 ’’ E, 500 m, mud, 4 specimens.