Aphanodomus C.B. Wilson, 1924

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 : 64

Genus Aphanodomus C.B. Wilson, 1924

Diagnosis. Body of adult female highly transformed, lacking any traces of segmentation. Body transversely elongate with paired egg sacs emerging from integument-lined, common genital aperture located posteriorly, in mid body ( Fig. 27F ). Maximum dimension (body width) of female ranging from 3 mm to 5 mm. Anteriorly, body with axopore opening into axocoel within parasite and connecting to body cavity of host. Mature adult male reduced to testis housed within receptaculum masculinum in female. Nauplius lecithotrophic, lacking naupliar eye.

Type species: Aphanodomus terebellae ( Levinsen, 1878) by original designation.

Remarks. The genus Aphanodomus was established by Wilson (1924) as a replacement name for Crypsidomus Levinsen, 1878 , which was preoccupied by Crypsidomus Günther, 1864 (Reptilia) . The organization of the highly modified body of Aphanodomus is similar to that of Xenocoeloma ( Bresciani & Lützen 1974) . The major morphological difference between the adult females is the elongate cylindrical to globular body with pores at each end in Xenocoeloma , compared to the irregularly cucumber-shaped body of Aphanodomus with pores in middle of the long sides (anterior and posterior). The early stage male of Aphanodomus is a simple vesicle lying within the thin walls of squamous epithelium, and it takes up the shape of the receptaculum masculinum. The later stage male differentiates into a functional testis ( Bresciani & Lützen 1974).

Figures

FIGURE 27. Xenocoeloma alleni (Brumpt, 1897). A, ectosoma of ovigerous female from Amaeana trilobata; B, ectosoma of ovigerous female from Polycirrus norvegicus caught in Norwegian waters. Xenocoeloma brumpti Caullery & Mesnil, 1915. C. ectosoma of ovigerous female from Polycirrus norvegicus caught in Liverpool Bay. Xenocoeloma orbicularis sp. nov. ovigerous female holotype. D, ectosoma, dorsal view showing paired eggs sacs emerging from common pore; E, same, lateral. Aphanodomus terebellae (Levinsen, 1878) adult female, F, habitus with 1 multiseriate and 1 spent egg sac. Scale bars: A, B, C, F, 1.0 mm; D, E, 0.5 mm.