The taxonomy of Campylaimus was reviewed first by Tchesunov (1978) and later by Huang & Zhang (2006), Tchesunov & Miljutina (2008) and Villares et al. (2013). Tchesunov (2006) suggested that an effective taxonomic approach for Campylaimus would be to clarify, organize and compile taxonomic information about the amphid form and lateral alae. Using Campylaimus -like forms of modern species, he constructed a transformational series, proposing a hypothetical evolutionary scheme for development of the amphid (Tchesunov 2006).
We further suggest that species of Campylaimus differ from one another in the detailed morphology of the form and length of the amphidial fovea, the width of the lateral alae, supplementary organs and copulatory apparatus.
These additional taxonomic characters are included in an emended diagnosis of the genus.
Diagnosis (modified from Tchesunov 2006; Tchesunov & Miljutina 2008; Villares et al. 2013):
Cuticle annulated, annules without ornamentation. Anterior end with a clearly visible cuticular fold covering mouth or terminal “cap”. Subdorsal or dorsal (rarely ventral) oral opening. Two pairs of cephalic setae; dorsal pair located a little posterior to ventral. Buccal cavity small, weakly cuticularized, unarmed. Pharynx cylindrical; nerve ring shifted to posterior end of pharynx. Ventral pore in posterior half of the pharynx, if present. Amphids comprised of an elongate loop with 2 parallel almost equal or unequal limbs connected anterior or posterior to the oral opening; ventral limb completely fused with lateral alae that are equal to or narrower than its width. Amphid limbs joined or with a wide gap between them. Lateral field wide or present as a prominent narrow alae, extending the length of the body and terminating near the tail tip. The boundary between amphid limb and lateral field may or may not be welldefined. Females with two outstretched ovaries. Males usually with two testes; occasionally the posterior one is absent. Spicules arcuate, without or with gubernaculum, apophyses plate-like or weak. Supplements as precloacal papillae may be present or absent. The tail is conical or cylindro-conical.
Type species: C. inaequalis Cobb, 1920.
Campylaimus abditus Bussau, 1993.
Campylaimus amphidialis sp. nov.
Campylaimus arcuatus Villares, Martelli, Lo Russo & Pastor, 2013. Campylaimus bonariensis Villares, Martelli, Lo Russo & Pastor, 2013. Campylaimus cylindricus Gerlach, 1956.
Campylaimus gerlachi Timm, 1961.
Campylaimus inaequalis Cobb, 1920.
Campylaimus lefeverei Gerlach, 1956.
Campylaimus minor Timm, 1961.
Campylaimus minutus sp. nov.
Campylaimus mirus Gerlach, 1950.
Campylaimus orientalis sp. nov.
Campylaimus patagonicus Villares, Martelli, Lo Russo & Pastor, 2013. Campylaimus ponticus Sergeeva, 1981.
Campylaimus pulcher sp. nov.
Campylaimus rimatus Vitiello, 1974.
Campylaimus siwaschensis Sergeeva, 1981. Campylaimus striatus Boucher & Helléouët, 1977. Campylaimus tkatchevi Tchesunov, 1978.