Gryllophila skrjabini (Sergiev, 1923)

Rusconi, José Matias, Achinelly, Maria Fernanda & Camino, Nora Beatriz, 2017, First record of Gryllophila skrjabini Sergiev, 1923 and Cephalobellus magalhaesi Schwenk, 1926 (Nematoda: Thelastomatidae) parasites of Neocurtilla claraziana Saussure, 1874 (Orthoptera: Gryllotalpidae) in Argentina, Papéis Avulsos de Zoologia (São Paulo) 57 (37), pp. 473-480 : 474

Gryllophila skrjabini (Sergiev, 1923)

Description

Morphology

Female: 3.4 mm long. Cuticule conspicuously striated; first annule 17 µm large, the following annules increases regularly until the ninth annule which is 50 µm wide; posterior to the ninth annule a width of 30 to 40 µm is maintained almost regularly; behind the vulva they may decrease to 10 µm only ( Fig. 1A ). Oral opening subtriangular, surrounded by a circumoral elevation and eight labiopapillae; amphids present. Buccal cavity cylindrical, 20 µm deep by 10 µm wide. Oesophagus 446 µm long, consisting of a corpus of 316 µm by 45 µm wide, an isthmus 30 µm long by 35 µm wide, and a valvular bulb 100 µm long by 110 µm wide. Nerve ring 184.5 µm from anterior end of body. Excretory pore very much posterior to base of oesophagus, at about one-third of body length from anterior end ( Fig. 1C ). Intestine dilated anteriorly to form a bulky cardia, which narrows suddenly into a rather thin intestine ( Fig. 1A ). Anus 337. 5 µm from the posterior end of body; tail conically attenuated ( Fig. 1F ). Vulva in the posterior third of the body. Two ovaries, both connected with their respective uteri at about the level of the excretory pore, the uteri running parallel in a posterior direction, uniting a little behind the level of the vulva and giving rise to a single uterus which runs anteriad, coming up to the level of the excretory pore where it is reflexed and runs backwards until it meets the vagina; vagina long ( Fig. 1E ). Ellipsoidal large eggs (144 to 155 µm long by 90 to 99 µm wide), with a thick shell bearing spine-like outgrowths ( Fig. 1D ), placed in a two-cell stage and chained by a tubular structure probably formed by a mucous secretion oviduct ( Basir, 1956; Shah et al., 2012).

Morphometry

Female (n = 3): total length = 3451.5 ± 27 (3432-3471), cephalic diameter = 18, distance from anterior end to nerve ring = 184.5 ± 6.36 (180-189), width at level of nerve ring = 202.5 ± 6.36 (198-207), oesophagus length = 446 ± 7.07 (441-451), anterior distance to basal bulb = 329 ± 7.07 (324-334), distance from anterior end to excretory pore = 948.5 ± 4.9 (945-952), greatest width = 445 ± 5.6 (441-449), width at level of vulva = 322 ± 9.8 (315-329), vulval length = 18, vulval width = 36 V = 74% ± 1 (73%-75%), posterior end width = 265.6 ± 63 (261-270), tail length = 337.5 ± 6.3 (333-342), egg length = 147.6 ± 7.7 (144-155), egg width = 96 ± 6.3 (90-99).

Male: not found.

Host: adults of the mole cricket Neocurtilla claraziana Saussure, 1874 .

Locality: Villa Elisa (34°52’02”S; 58°04’28”W)

Site of infection: hindgut (last part of intestine).

Prevalence: 0.3%.

Figures

FIGURE 1: Gryllophila skrjabini. (A) Female, entire. (B) Cephalic region. (C) Excretory pore (maximized). (D) Egg showing spine-like outgrowths. (E) Vulval region. (F) Posterior region.