Campydoroides Holovachov, 2019

Holovachov, Oleksandr, 2019, Campydoroides manautei gen. et sp. nov. from New Caledonia and a reappraisal of the suborder Campydorina (Nematoda), European Journal of Taxonomy 518, pp. 1-23 : 6-8

Genus Campydoroides Holovachov gen. nov.

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Diagnosis

Cuticle transversely striated. Lateral alae, body pores and epidermal glands absent. Somatic sensilla distinct along anteriormost part of pharyngeal region and on tail. Labial region truncated. Six inner labial papilliform sensilla, located on anterior surface of lips. Six outer labial papilliform sensilla, located on periphery of labial region. Four cephalic papilliform sensilla, located a short distance behind labial region. Amphid stirrup-shaped with transverse slit-like opening. Stoma conoid, stegostom with strongly cuticularised walls and large protrusible dorsal tooth. Pharynx cylindrical anteriorly, with distinct basal bulb; valves absent. Cardia ovoid, partially embedded into intestinal tissue. Secretory-excretory system absent. Female reproductive system didelphic, amphidelphic, ovary branches reflexed antidromously. Vulva a transverse slit. Vagina straight, without pars refringens vaginae or epiptygmata. Spermatheca absent. Male reproductive system unknown. Tail elongate. Caudal glands and spinneret present.

Type species

Campydoroides manautei Holovachov gen. et sp. nov. (type by original designation).

Relationships

The new genus shows close affinities to the genera Campydora Cobb, 1920 and Udonchus Cobb, 1913 in having papilliform labial and cephalic sensilla, stirrup-shaped amphid with transverse slit-like opening, stoma with well-developed protrusible dorsal tooth, and muscular pharynx with stronglydeveloped basal bulb. The new genus differs from Campydora in detailed stoma morphology (conoid with strongly cuticularised walls and large dorsal tooth in Campydoroides gen. nov. vs cylindrical with weakly cuticularised walls and small dorsal tooth in Campydora ), secretory-excretory system (absent in Campydoroides gen. nov. vs present in Campydora ), cuticle (without longitudinal ridges in Campydoroides gen. nov. vs with ventral and dorsal ridges in Campydora ) and tail (caudal glands and spinneret present in Campydoroides gen. nov. vs absent in Campydora ). From Udonchus the new genus can also be easily separated by detailed stoma morphology (conoid with strongly cuticularised walls in Campydoroides gen. nov. vs cylindrical with weakly cuticularised walls in Udonchus ) and number of teeth (single dorsal tooth in Campydoroides gen. nov. vs three small denticles in Udonchus ). Further diagnostic characters separating the genus Campydoroides gen. nov. from all other genera considered in the suborder Campydorina are listed in the Table 2 and the identification key.

Overall morphology of the anterior end (papilliform labial and cephalic sensilla, stirrup-shaped amphid with transverse slit-like opening, stoma with well-developed dorsal tooth) is similar to that found in the members of the order Mononchida Jairajpuri, 1969 ( Peña-Santiago 2014). However, the presence of a basal pharyngeal bulb in Campydoroides gen nov. is a feature never observed in any species of mononchid nematodes. In fact, the basal pharyngeal bulb is rarely present in non-chromadorean nematodes (those

belonging to Enoplia Pearce, 1942 and Dorylaimia Inglis, 1983, see Schmidt-Rhaesa 2014), and is here considered one of the diagnostic features of the suborder Campydorina (see below).