Spinitectus asperus Travassos, Artigas & Pereira, 1928

Ramallo, Geraldine, Cancino, Fabiana, Ruiz, Ana Lía & Ailán-Choke, Lorena Gisela, 2020, Gastrointestinal nematodes of freshwater fish from Pilcomayo River, Argentina including description of a new species of Procamallanus (Spirocamallanus), Zootaxa 4810 (3), pp. 468-480 : 474-475

Spinitectus asperus Travassos, Artigas & Pereira, 1928

Host: Prochilodus lineatus (Valenciennes, 1837) (CI-FML #2666)

Locality: Misión La Paz, Pilcomayo River, Rivadavia Department , Province of Salta (22º22’10”S- 62º32’14”W)

Site of infection: cardial region of the stomach

Quantitative descriptors: Table I

Deposition of voucher specimen: CH-N-FML#7773.

General description. Small nematodes. Small, posteriorly directed cuticular spines diminishing posteriorly.

Ring of cuticular spines laterally interrupted in some regions of the body (excretory pore, vulva). Rings starting at 0.015 -0.020 mm below anterior end; in female finishing 0.050 from posterior end; in male disappearing before the anus. Number of spines per ring increasing from 16 at first ring to 60 in male and 90 in female at level of the glandular esophagus; in more posterior rings number of spines decreasing in female to be about 30 at level of anus. Oral opening covered by two well-developed pseudolabia bearing amphids and submedian papillae and four (2 dorsal and 2 ventral) submedian lips. Vestibule long without prostom. Muscular esophagus short and glandular esophagus long. Nerve ring posterior to end of vestibule. Glandular ring that surrounds the esophagus and is located below the nerve ring.

Males (based on two specimens). Length of body 4.00-4.71 maximum width 0.15-0.17. Length of vestibule 0.11–0.13. Esophageal gland ring 0.13-0.14 from anterior end. Muscular oesophagus length 0.20-0.24. Glandular oesophagus length 1.55–1.58. Nerve-ring and excretory pore 0.10 and 0.15–0.16, respectively, from anterior extremity. Caudal alae large. Caudal papillae: 4 pairs of preanal papillae and 5 pairs of postanal papillae. Phasmids not observed. Spicules very different from each other: large (left) spicule 0.22-0.23, its distal end with two lateral barbs; small (right) spicule 0.08, boat-shape. Tail 0.12-0.15 long.

Females (based on five specimens). Length of body 6.05–11.00, maximum width 0.22-0.32. Length of vestibule 0.11–0.13. Esophageal gland ring 0.15-0.16 from anterior end. Muscular oesophagus length 0.22–0.29. Glandular oesophagus length 1.50–1.97. Nerve ring and excretory pore 0.13–0.15 and 0.25–0.33, respectively, from anterior extremity. Vulva postequatorial, 3.40–5.40 from posterior end of body. Uterus amphidelphic. Mature eggs oval, embryonated, without filaments. Tail 0.20–0.27 long.