Sphaerodoridium gudmunduri (Moreira & Parapar, 2012) Moreira & Parapar, 2012

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 : 73-75

Sphaerodoridium gudmunduri (Moreira & Parapar, 2012) comb. n. Figs 5W, 23I, J, 29

Sphaerodoropsis gudmunduri Moreira & Parapar, 2012: 585-588, figs 1A, 2-3, 6 A–C.

Type locality.

Northwest Iceland, 66°33.95'N, 20°00.71'W, 97 m.

Material examined.

(11 specs) South Greenland: ZMBN 127350 (5 spec.), 63°07'N, 52°17'W, 162.5 m, 06 Nov 2002; NTNU-VM 74199 (2 specs on SEM stub), 63°07'N, 52°17'W, 162.5 m, 06 Nov 2002. Norwegian Sea: ZMBN 127349 (6 spec.) 64°26.1'N, 11°10.2'W, 400 m, 07 Jun 1983.

Diagnosis.

Body short and ellipsoid, less than 2 mm long. Prostomial appendages smooth, lacking spurs. Median antenna as long or slightly shorter than other prostomial appendages. Lateral antennae, palps, and tentacular cirri of similar shape and length. Antenniform papillae absent. 8-12 longitudinal rows of large spherical and sessile macrotubercles in one transverse row per mid-body segment. Dorsum without papillae; ventrum with seven (♂) or 9 (♀) spherical papillae per segment. Parapodia with 1-4 papillae. Acicular lobe from chaetigers 3-4, digitiform. Ventral cirri digiti form, projecting well beyond acicular lobe. Compound chaetae with short blades (less than five times its maximum width), showing little dorso-ventral gradation; unidentate and fine spinulation along its cutting margin.

Remarks.

This is the first report of this species from southern Greenland. Specimens show some minor variations to original description. The species was described with 20-25 chaetigers but specimens with less segments have been found (16-19, Fig. 29A), measuring 1.5-2 mm long, 0.5-0.8 mm wide, and with maximum number of macrotubercles in mid-dorsal segments of eight (Fig. 29A) instead of the 10-12 previously described ( Moreira and Parapar 2012). This variation could be size related, since the specimens examined for this study are smaller and have less segments than those from original description. Females with small oocytes visible through epidermis. Males observed with a pair of digitiform and distally opened sexual structures between parapodia or segments 7-8 (Fig. 23J), as in original description ( Moreira and Parapar 2012). Other diagnostic features are shared by the North East and South Greenland specimens.

Differences between this species and other congeners are the large, sessile, and spherical macrotubercles, arranged in one single transversal row of up to 12 per segment, and absence of any other dorsal papillae (Fig. 29A). Other members of Sphaerodoridium with sessile macrotubercles bear also additional papillae between transverse rows. In addition, S. gudmunduri comb. n. presents large papillae in ventrum, especially close to the lateral edges, nearby the parapodia (Fig. 29D). All other Sphaerodoridium bear smaller ventral papillae.

Distribution.

From East Iceland to South Greenland, Norwegian Sea ( Moreira and Parapar 2012, present study).

Habitat.

Silty sand, at depths of 88-400 m ( Moreira and Parapar 2012, this study).