Lanassicola, Boxshall & O’Reilly & Sikorski & Summerfield, 2019

Boxshall, Geoff A., O’Reilly, Myles, Sikorski, Andrey & Summerfield, Rebecca, 2019, Mesoparasitic copepods (Copepoda: Cyclopoida) associated with polychaete worms in European seas, Zootaxa 4579 (1), pp. 1-69 : 45

Genus Lanassicola gen. nov.

Diagnosis. Ectosoma of adult female comprising cephalothorax, unsegmented trunk and genitoabdomen; body typically elongate and dorsoventrally flattened; cephalothorax undifferentiated or weakly delineated from postcephalic trunk by dorsal surface suture. Cephalothorax with or without dorsal and antero-lateral lobes. Ectosoma attached to host via stalk originating anteriorly in oral region and connecting to small discoid endosoma within host. Trunk dorsoventrally flattened, typically about 3 to 4 times longer than wide, lacking vestiges of limbs. Cement glands paired, slender, extending through posterior third of trunk. Paired genital apertures located posterolaterally, not on conspicuous swellings. Posterior margin bilobate, with anus in midline. Egg sacs multiseriate. Antennule lobate. Antenna 2-segmented; distal segment with paired apical adhesion pads. Maxillae comprising basal segment, distal segment with paired apical pads.

Body of adult male ovoid, comprising fused cephalothorax and trunk. Antennules unsegmented, elongate, bearing up to 5 setal elements along anterior and distal margins. Antennae and maxillae as in female. Oral region enclosed by subrectangular chitinous framework, referred to here as oral funnel, containing paired rounded lobes densely ornamented with long setules plus smaller anterior lobe.

Type species: Lanassicola arcticus gen. et sp. nov., by original designation

Etymology. The name of the new genus is based on a combination of Lanassa , the name of the host genus, and – icola, meaning inhabitant: gender masculine.

Remarks. The new genus shares with other saccopsids, the typical construction of both the antenna and maxilla. The antenna is 2-segmented and the distal segment carries paired pads apically. The maxillae are located posterior to the stalk and carry 2 adhesion pads apically. This derived limb morphology is shared with Melinnacheres and supports the placement of the new genus in the Saccopsinae. The new genus can be distinguished from Melinnacheres and Trichobranchicola gen. nov. by its elongate and strongly dorsoventrally flattened female body, and by the presence of paired antennules represented by unarmed anterior lobes. The paired genital apertures are less prominent in the new genus than in Melinnacheres and Trichobranchicola gen. nov.

The body of the male of the new genus is sac-like and shares the possession of paired antennules, antennae and maxillae with the males of both Melinnacheres and Trichobranchicola gen. nov. The antennules are unsegmented and carry 4 or 5 setal elements. The post-cephalic trunk of male Melinnacheres tapers posteriorly and appears to carry paired posterolateral genital openings. No genital apertures are present on the trunk of Lanassicola gen. nov. males (see below for discussion of reproductive biology in the Saccopsidae ).

The type species, Lanassicola arcticus gen. et sp. nov., and the two other new species of Lanassicola gen. nov. described below occur on hosts belonging to the subfamily Terebellinae , within the Terebellidae .