Goffartia variabilis ( Micoletzky, 1922 ) Hirschmann, 1952

Tahseen, Qudsia & Mustaqim, Malka, 2015, A taxonomic review of the genus Goffartia Hirschmann, 1952 (Rhabditida: Diplogastridae) with a note on the relationship of congeners, Zootaxa 4034 (1) : -

Goffartia variabilis ( Micoletzky, 1922) Hirschmann, 1952

( Figs. 1 D, 2D, 3D, 6)

= Diplogasteroides variabilis Micoletzky, 1922

Measurements. Table 1

Description. Adults: Medium- to large-sized nematodes, between 0.8–1.2 mm in length. Cuticle with moderate transverse annulations and longitudinal striations. Lateral field with four incisures. Lip region rounded to slightly truncate, labial sensilla small, slightly raised. Amphidial apertures almost rectangular in outline, deeply carved into cuticle, double the width of buccal cavity, about one-third of the corresponding body width from anterior end. Stoma barrel-shaped, rarely longer than lip width, with weakly cuticularised cheilostom with walls straight or slightly diverging posteriorly; gymnostom and stegostom cuticularised giving a fusiform shape to the stoma. Pharyngeal corpus weakly developed, anterior part shorter than posterior part of pharynx, median bulb small with less cuticularised valve plates, isthmus narrow, leading to an oval basal bulb. Excretory pore visible, at the level of basal bulb. Tail long filiform with whip-like posterior part.

Female: Reproductive system didelphic, amphidelphic, both genital branches almost equal; vulva preequatorial.

Male: Similar to female in other morphological characters. Tail divided into an anterior conical part and an abruptly narrowing cylindrical part terminating in a whip. Spicules slender, 21–23 µm, about as long as cloacal body diameter, gubernaculum trough-shaped with blunt proximal end, about half of spicule length. Nine pairs of genital papillae present with 2 precloacal and 7 postcloacal pairs in the configuration: v1, v2 / v3 d, v4, ad, (v5 + v6, v7), pd. The precloacal pairs v1 and v2 spaced and subventrally placed; v3 d slightly postcloacal, lateral; v4 subventral about a spicule length posterior to cloacal lip; ad lateral almost equidistant from v4 and v5; subventrally placed v5 and v6 closely spaced and distant from v7; pd pair placed subdorsally.

Locality and habitat. Goffartia variabilis is an inhabitant of freshwater reservoirs, although in wet soil it is reported to be phoretically associated with the Carabid beetle, Elaphrus riparius Linnaeus, 1758 and usually settles in the inter-segmental folds of the host’s abdomen ( Steffan 1967). The species is widespread in Europe, Lake Baikal and Lake Taymyr in the territory of Russia ( Holovachov 2014) and also reported from Italy, Poland, Denmark and Egypt ( Zullini 1982).

Salient characters. Cuticle striated transversely and longitudinally; lip region rounded to truncate with labial sensilla slightly raised; amphidial apertures about one-third of corresponding body width or two times stoma width; stoma barrel-shaped, rarely longer than lip width, with gymnostom and stegostom giving a fusiform appearance; pharyngeal corpus and median bulb weakly developed; anterior part of pharynx shorter than posterior part; both genital branches of female gonad almost equal; males with cephalated, slender spicules; gubernaculum troughshaped with blunt proximal end, about half of spicule length and genital papillae v5 and v6 closely placed and slightly distant from v7.

Figures

FIGURE 1. Anterior body ends. A: Goffartia africana. B: G. filicaudata. C: G. heteroceri. D: G. variabilis. E: G. praepilata. F: G. phalacra. G: Female reproductive system in Goffartia sp. (Scale bar = 10 µm).