Paratrichodorus, SIDDIQI, 1974

GENUS PARATRICHODORUS SIDDIQI, 1974 View in CoL

Amended diagnosis: Cuticle usually clearly swollen when fixed or heat-killed. Female reproductive system didelphic–amphidelphic. Lateral body pores present in ~50% of the species but rarely located post-advulvar; body pores exceptionally ventral or sub-ventral in position. Vagina short (about one-third of corresponding body diameter), constrictor muscles inconspicuous, vaginal sclerotization small to inconspicuous in lateral view. Males rare or unknown in ~25% of the species. Ventromedian cervical papillae in male absent or, if present, usually one papilla near the secretory–excretory (S-E) pore, exceptionally with two. Lateral cervical pores absent or, if present, usually one pair near onchiostyle base or S-E pore. Male tail region straight; caudal alae present, obscure to distinct. Sperm cells variable, large size with large sausage-shaped nucleus, medium-sized with rounded nucleus, small with small oval to rounded nucleus or thread-like (degenerated) with nucleus obscure, rarely sperm exceptionally long, fusiform with elongated nucleus. Oblique copulatory muscles poorly developed and restricted to spicule region; capsule of spicule suspensor muscles inconspicuous. Spicules usually straight and blade about equally wide and often finely striated; no bristles nor velum. One to three ventromedian precloacal supplements, exceptionally four; usually two supplements within spicule region, rarely with a single supplement. Usually one pair, rarely two, subventral postcloacal papillae. A pair of caudal pores present, rarely absent. Type species: Paratrichodorus tunisiensis (Siddiqi, 1963) Siddiqi, 1974 .

Remarks: Species determination of the P. hispanus group was based upon the integrative approach, applying morphological and molecular methods in order to unravel potential cryptic species diversity. The Spanish samples revealed two main species groups among the Paratrichodorus species found: (1) species possessing large sperm cells with a sausage-shaped or rounded nucleus; and (2) species with small or non-functional sperm cells. Within the first species group, all species have males with undulating spicular calomus; the group is referred to as the P. hispanus species group. The second group of species, or the P. allius species group, will be dealt in detail in a separate paper.