Cyclorhiza eteonicola Heegaard, 1942

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 : 30-31

Cyclorhiza eteonicola Heegaard, 1942

Material examined: 1 ovigerous ♀ from Eteone spetsbergensis Malmgren, 1865 , 3697 Svalbard, Adventfjorden, Stn 5-4 (78° 13’00”N, 15° 13’00”E), depth 30-60 m, 0 8 September 2011; collected by A. Sikorski; NHMUK Reg. No. 2016.520.

Differential diagnosis. Adult female body comprising ectosoma connected to endosoma via short stalk. Ectosoma of mature female 2.1 times longer than maximum width (length 0.93 mm, maximum width 0.44 mm); tapering posteriorly. Ectosoma bearing antennules, antennae and maxillipeds typical for genus; lacking any vestige of trunk limbs and caudal rami. Anus lacking. Genital apertures paired, located anteriorly on underside of ectosoma. Egg sacs 4.55 mm long: egg arrangement multiseriate with about 5 longitudinal rows visible in any view ( Fig. 12 ); eggs spherical, mean diameter 92 µm (range 84 to 104 µm). Stalk short and broad, connecting to endosoma within host. Endosoma comprising 2 elongate rootlets penetrating body cavity of host.

Remarks. Heegaard (1942) based his original description on two females found on Eteone longa collected in sand on an island beach outside Trondheim fjord (western Norway). It was subsequently reported from the east coast of North America by Lützen (1964b) on E. longa . The female recorded here was collected from Eteone spetsbergensis , a new host, and it was attached in the mid-body region of its host ( Fig. 10 ). Cyclorhiza eteonicola was reported from UK waters by O’Reilly & Geddes (2000), who found 5 non-ovigerous females on E. longa near Holy Island, off the coast of Northumberland. However, O’Reilly (2000) subsequently concluded that this material could equally be attributed to C. megalova since egg size is diagnostic and these specimens were non-ovigerous.

Figures

FIGURE 10. Pholoicola chambersae gen. et sp. nov. A, adult female with 3 males attached, ventral; B, female, dorsal; C, detached egg sac; D, adult male, lateral view showing position of developing paired spermatophores; E, adult male, ventral; F, cephalothorax of male, lateral view showing thickened frontal region and clawed limb; G, spermatophore; H, last male copepodid stage, antennule; I, antenna; J, maxilliped. Scale bars: A, 0.5 mm, B–C, 250 µm, D–E, 50 µm, F–H, 25 µm, I–J 10 µm.

FIGURE 12. Cyclorhiza eteonicola Heegaard, 1942. Micro-CT rendering of ovigerous female attached to host, Eteone spetsbergensis. Scale bar: 2 mm.