Description of Meloidoderita salina sp. n. (Nematoda, Sphaeronematidae) from a micro-tidal salt marsh at Mont-Saint-Michel Bay in France

Abstract

Meloidoderita salina sp. n. is described and illustrated from the halophytic plant Atriplex portulacoides L. (sea purslane) growing in a micro-tidal salt marsh in the Mont-Saint-Michel Bay in France. This new species is the first member oí Meloidoderita Poghossian, 1966 collected from a saline environment, and is characterized by the following features: sedentary mature females having a small swollen body with a clear posterior protuberance; slightly dorsally curved stylet, 19.9 [im long, with posteriorly sloping knobs; neck region irregular in shape and twisted; well developed secretory-excretory (S-E) pore, with markedly sclerotized S-E duct running posteriorly; prominent uterus bordered by a thick hyaline wall and filled. with eggs. The adult female transforms into a cystoid. Eggs are deposited in both egg-mass and cystoid. Cystoids of Meloidoderita salina sp. n. display a unique sub-cuticular hexagonal beaded pattern. Male without stylet, pharyngeal region degenerated, S-E duct prominent, deirids small, developed testis 97.5 [im long, spicules 18.4 um long, cloacal opening ventrally protruded, small phasmids posterior to cloaca opening and situated at 5.9 (3.2-7.7) [im from tail end, and conical tail ending in a rounded terminus marked with one (rarely two) ventrally positioned muero. Additionally, some young males of the new species were observed enveloped in the last J2 cuticle. Second-stage juvenile body 470 um long, with a 16.4 um long stylet, prominent rounded knobs set off from the shaft, hemizonid anterior and adjacent to S-E pore, small deirids located just above S-E pore level, genital primordium located at 68-77% of body length, phasmids small and located at about 19 um from tail tip, and tail 38.7 um long, tapering to finely pointed terminus with a finger-like projection. Phylogenetic analyses based on the nearly full length small subunit ribosomal DNA sequences oí Meloidoderita salina sp. n. revealed a close relationship of the new species with Sphaeronema alni Turkina & Chizhov, 1986 and placed these two species sister to the rest of Criconematina. © Samad Ashrafi et al.