Commensodorum Fauchald, 1974

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 : 21

Commensodorum Fauchald, 1974

Commensodorum Fauchald, 1974: 265-266; Capa et al. 2014: 16.

Type species.

Sphaerodoridium commensalis Lützen, 1961.

Diagnosis.

Body ellipsoid. Head with a median and a pair of lateral antennae; antenniform papillae absent; all appendages short. Tubercles sessile, conical, or pear-shaped, in four longitudinal rows, one transverse row per segment, except for first chaetiger with only two. Minute epithelial papillae on dorsal and ventral surfaces, in ca. 5-6 transverse rows per segment. Parapodia with rounded and small ventral cirri, not surpassing tip of acicular lobe. Stout hooks in anterior chaetigers absent. All chaetae simple, unidentate chaetae, enlarged subdistally, with serrated edge.

Remarks.

Referring to the main dorsal tubercles in Commensodorum as macrotubercles (e.g., Fauchald 1974) is herein avoided due to their smaller size compared to other members of the family. Members of this group have not been included in molecular analyses due to absence of material properly fixed for DNA extraction and sequencing and therefore relationships with other sphaerodorids remains unknown. The number of longitudinal rows of dorsal tubercles resembles the arrangement of macrotubercles in members of Sphaerephesia (as redefined in this study). However, tubercles in Commensodorum are smaller than in any other sphaerodorid. Shape of simple chaetae somehow resembles those of Euritmia , but they are thinner in the only species described in the genus, Commensodorum commensalis ( Lützen, 1961).

The genus is monotypic.

Commensodorum commensalis ( Lützen, 1961).

Type locality: Gullmarfjord, Sweden, 35 m.