Sphaerodoridium amoureuxi (Aguirrezabalaga & Ceberio, 2005) Aguirrezabalaga & Ceberio, 2005

Capa, Maria, Nygren, Arne, Parapar, Julio, Bakken, Torkild, Meissner, Karin & Moreira, Juan, 2019, Systematic re-structure and new species of Sphaerodoridae (Annelida) after morphological revision and molecular phylogenetic analyses of the North East Atlantic fauna, ZooKeys 845, pp. 1-97 : 62-64

Sphaerodoridium amoureuxi (Aguirrezabalaga & Ceberio, 2005) comb. n. Figs 5S, 23A, B

Sphaerodoropsis amoureuxi Aguirrezabalaga & Ceberio, 2005: 10-13, figs 1, 2; Moreira et al. 2011: 28-29, fig. 2; Moreira 2012, 36-39, fig. 11.

Type locality.

Capbreton Canyon, Bay of Biscay, 984-1029 m.

Material examined.

Holotype: MNCN 16.01/8925, Capbreton Canyon, Bay of Biscay, 984-1029 m. Paratype: not found in MNHN, seems to be missing.

Additional material.

(1 spec) NW Iberian Peninsula: MNCN 16.01/13269 (1 spec.), 43°36.22'N, 08°52.84'W, 200 m, 26 Sep 2004.

Diagnosis.

Body short and cylindrical, less than 3.5 mm long. Palps, lateral antennae, and tentacular cirri, with spurs or basal papillae (lateral antennae 6-8). Median antenna smooth, shorter than other head appendages. Antenniform papillae present. Dorsal macrotubercles sessile, almost spherical, arranged in eight longitudinal rows in a single transverse row per segment, from segment 3. Dorsum with additional large spherical papillae, arranged between macrotubercles in more or less clear transverse rows, 25-30 papilla per segment. Ventrum with ca. 20 small spherical papillae per segment in midbody, arranged in 3-4 transverse rows per segment. Parapodia with three papillae; two sub-equal spherical papillae on ventral and anterior surfaces, and one postchaetal terminal papilla. Acicular lobe from segment 3. Approximately 6-8 compound chaetae with medium blades (up to seven times as long as wide), showing slight intra-fascicle variation in size.

Remarks.

This species has been described in detail ( Aguirrezabalaga and Ceberio 2005) and some additional intraspecific variation has been reported ( Moreira et al. 2011) and incorporated in the diagnosis. The antenniform papillae can be contracted and not evident in some specimens; variation regarding the number of parapodial papillae with three instead of 2-4. The postchaetal lobes mentioned in the original description and by Moreira et al. (2011) are herein considered a distal postchaetal papilla. Some macrotubercles seem to have a short stalk (or at least they are almost spherical) in the types re-examined. Sphaerodoropsis amoureuxi comb. n. belongs to the clade of sphaerodorids with over six longitudinal rows of macrotubercles arranged in a single segmental transverse row. Females with visible eggs, sexual or sexual structures not observed.

Sphaerodoridium amoureuxi comb. n. differs from other congeners in the number of macrotubercles (up to eight, Fig. 23A), presence of spurs and basal papillae in paired head appendages, and shape, number of papillae per segment (spherical, 24-30, Fig. 5S) and chaetal morphology, with blades up to seven times as long as wide. The description of this species was justified based in the number of head appendages ( Aguirrezabalaga and Ceberio 2005), a feature that seems to show some variability ( Moreira et al. 2011), and the number of parapodial lobes ( Aguirrezabalaga and Ceberio 2005), but these could have a different misinterpretation and be considered as parapodial papillae ( Moreira et al. 2011 and herein).

Distribution.

Capbreton Canyon, Bay of Biscay ( Aguirrezabalaga and Ceberio 2005); NW Iberian Peninsula ( Moreira et al. 2011).

Habitat.

Soft bottoms between 100-1030 m ( Moreira 2012).