A new species of Trichosomoididae (Nematoda) from skin of red snapper, Lutjanus campechanus (Perciformes: Lutjanidae), on the Texas-Louisiana shelf, northern Gulf of Mexico.

Eggs and larvae of Huffmanela oleumimica n. sp. infect red snapper, Lutjanus campechanus (Poey, 1860), were collected from the Texas-Louisiana Shelf (28°16'36.58″N, 93°03'51.08″W) and are herein described using light and scanning electron microscopy. Eggs in skin comprised fields (1-5 × 1-12 mm; 250 eggs/mm(2)) of variously oriented eggs deposited in dense patches or in scribble-like tracks. Eggs had clear (larvae indistinct, principally vitelline material), amber (developing larvae present) or brown (fully developed larvae present; little, or no, vitelline material) shells and measured 46-54 µm (x = 50; SD ± 1.6; n = 213) long, 23-33 (27 ± 1.4; 213) wide, 2-3 (3 ± 0.5; 213) in eggshell thickness, 18-25 (21 ± 1.1; 213) in vitelline mass width, and 36-42 (39 ± 1.1; 213) in vitelline mass length with protruding polar plugs 5-9 (7 ± 0.6; 213) long and 5-8 (6 ± 0.5; 213) wide. Fully developed larvae were 160-201 (176 ± 7.9) long and 7-8 (7 ± 0.5) wide, had transverse cuticular ridges, and were emerging from some eggs within and beneath epidermis. The new species differs from its congeners by having eggs <65 µm in total length and that have a brown eggshell when fully developed, an envelope throughout development, and irregularly-dispersed eggshell spines plus a larva >110 µm long with transverse cuticular ridges. The eggs lack a spindle-shaped envelope, polar filaments, and eggshell ridges. This is the first report of a species of Huffmanela from a snapper (Lutjanidae) or from the Gulf of Mexico. A table of egg and larval characteristics, hosts, and localities for Huffmanela spp. is provided.