Description: "Male: Body length 3-6mm, body width 0.14-0.2 mm. Longitudinal rows of cuticular spines present. Anterior end with lateral cuticular appendages. Buccal capsule 0.02-0.03mm long and 0.009-0.013mm in diameter. Cervical papillae asymmetrical, 0.14-0.16mm from anterior end. Oesophagus 0.79-1.44mm long with muscular part 0.32-0.45mm and glandular 0.47-0.76mm long. Nerve ring 0.18-0.245mm and excretory pore 0.225-0.27mm from anterior end. Long spicule 0.28-0.49mm long, short spicule 0.09-0.2mm long. Tail 0.21-0.265 mm long with conical appendage about 0.01 mm long and provided with spines.
Female: Body length 1.58-6.0mm, maximum body width 0.96-3.6mm. Buccal capsule 0.018-0.023mm long. Oesophagus 1.2-1.49mm long, with muscular part 0.21-0.315 mm long and glandular part 0.97-1.23mm long. Cervical papillae 0.11mm and nerve ring 0.13-0.185mm from anterior end. Tail 0.07-0.175mm long. Vulva 0.1-0.41mm from posterior end. Eggs 0.03-0.06 x 0.025-0.035mm" (Rysavy and Ryzhikov, 1978).
Life Cycle: “The life cycle is indirect involving an arthropod intermediate host. Eggs once passed with droppings hatch and are swallowed by intermediate hosts which are water crustaceans, Daphnia pulex, and Gammarus pulex. The final host acquires the infection following ingestion of the infected intermediate host. Immediately following ingestion, the male and female parasites migrate to the proventriculus where they embed in the glands. After copulation males migrate to the lumen and die” (Kamil et al., 2011).
Sources: Rysavy, B. and Ryzhikov, K.M. 1978. Helminths of Fish-Eating Birds of the Palaearctic Region: Nematoda. p. 216.
Kamil, S.A., Darzi, M.M., Mir, M.S., Shah, S.A., Shah, S.N. and Khan, F.A. 2011. Tetrameres Fissispina Infection in Ducks from Bandipora Area of Kashmir Valley. Israel Journal of Veterinary Medicine. Vol. 66, No. 2.