Geminofilum halldori (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 : 34-35

Geminofilum halldori (Moreira & Parapar, 2012) comb. n. Figs 4O, P, 5G, 13 A–F

Sphaerodoropsis halldori Moreira & Parapar, 2012: 588-591, figs 1B, 4-5, 6 D–F.

Type locality.

West Iceland, 64°26'N, 28°15'W, 1162 m.

Material examined.

Iceland (13 specs): IINH 38791 (3 specs), 65°15.61'N, 28°50.15'W, 1300 m, 28 Aug 1996; IINH 38792 (8 specs), 65°11.01'N, 29°04.18'W, 1456 m, 25 Aug 1996; IINH 38793 (2 spec. on SEM stub), 62°23.15'N, 28°16.91'W, 1558 m, 7 Sep 2003.

Diagnosis.

Body short and cylindrical, up to 3.5 mm long. Prostomial appendages smooth, lacking spurs or basal papillae. Dorsal macrotubercles sessile, almost spherical, arranged in two transverse rows per segment, with six and seven macrotubercles each, from segment 3. Dorsum with seven additional rounded papillae per segment in mid body, arranged in seven longitudinal rows. Ventrum with up to eight papillae per seg ment in mid body, arranged in six longitudinal rows and forming a V on each segment. Females with a pair of larger tubercles in chaetigers 7-9. Parapodia with one papilla on anterior surface from chaetiger 3. Acicular lobe from chaetiger 1-2. Compound chaetae, 4-8, with short blades (up to five times as long as wide), showing some intra-fascicle variation in size.

Reproductive features.

Some males filled with sperm and females with oocytes. Sexual structures of males as ventral cirri basally inflated, and with pores on ventral surface on chaetiger 6. Females with pair of oval, distally opened tubercle located ventro-laterally to parapodia on chaetigers 6-7 (Fig. 4P); in addition, ventral cirri of chaetigers 4-7 basally inflated and with ventral pores.

Variation.

Size range (type series): 2.5-3.1 mm long, 0.4 mm wide, with 17-20 chaetigers. Pigmentation absent in fixed specimens.

Remarks.

Geminofilum halldori comb. n. resembles G. bisphaeroserialis ( Hartmann-Schröder, 1974), comb. n., G. arctowskyensis ( Hartmann-Schröder & Rosenfeldt, 1988), comb. n., and G. garciaalvarezi ( Moreira et al. 2004), comb. n. in the general appearance, number and arrangement of dorsal macrotubercles (Fig. 13A, B), and the presence of one papilla on the anterior surface of parapodia (Fig. 5G). However, they can be distinguished by the number and arrangement of dorsal and ventral papillae. Geminofilum halldori comb. n. is characterised by presenting seven small and hemispherical papillae per segment from chaetiger 3 arranged in a transverse row between segments (Fig. 4O), and three in a row between parapodia (these features are not visible in Fig. 13, probably due to the contraction of animal and wrinkled epithelium). Chaetae show slight variation in size of blades within parapodia, but anterior chaetigers bear longer blades (Fig. 13E, F).

Distribution.

West Iceland ( Moreira and Parapar 2012, present study).

Habitat.

Sandy sediments, at depths of 1162-1558 m ( Moreira and Parapar 2012, this study).