Eutobrilus annetteae ( Joubert & Heyns, 1979 ) Tsalolikhin, 1983

Girgan, Chantelle, Marais, Mariette, Fourie, Hendrika, Tiedt, Lourens & Swart, Antoinette, 2019, Description of two new species, Aphanolaimus strilliae n. sp. (Nematoda: Aphanolaimidae) and Makatinus africanus n. sp. (Nematoda: Aporcelaimidae), and SEM observations on three known species from freshwater sources in the Telperion Nature Reserve (Mpumalanga, South Africa), Zootaxa 4651 (2), pp. 201-234 : 217-220

Eutobrilus annetteae ( Joubert & Heyns, 1979) Tsalolikhin, 1983

Figures 11–13

Measurements: Table 5

Description: Female (n = 18): Body 1049–1547 μm long, habitus C-shape, bent ventrally or dorsally. Cuticle 1–4 μm thick at mid-body, annulated. Body with several somatic setae, the first 14–63 μm from anterior end. Lip region 17–23 μm wide, cephalic setae 4–6 μm long. En face view of head shows first circlet of six labial papillae, second circlet of 10 cephalic setae consisting of six long cephalic setae and four slightly shorter cephalic setae. Amphid stirrup shaped with slit-like aperture, 14 μm from anterior. Stoma 22–27 μm long, with wide barrel shaped buccal cavity, 6–11 μm wide followed by two overlapping tooth pockets. The first tooth 10–19 μm from anterior end, second tooth 2–9 μm posterior from first. Oesophagus cylindrical, muscular, 225–300 μm long. Nerve ring situated 102 μm from anterior. Cardia 12–20 μm long with three prominent cells situated at junction of cardia and oesophagus. Excretory pore not observed. Reproductive system didelphic-amphidelphic, anterior and posterior tract equal in length. Vulva a transversal slit, equatorial at 41–50 % of the body. Vagina less than half corresponding body width. Vaginal musculature simple, weakly developed. Uterus simple, sphincter muscles indistinct. Ovaries reflexed with oocytes in a single row except on growth point. Rectum 23–33 μm long, slightly longer than anal body width. Tail 210–253 μm long ending in a 3–5 μm spinneret, subterminal setae absent. Three prominent caudal glands pres- ent in tail region.

Male: Not found.

Discussion: The Eutobrilus specimens found in the Telperion Nature Reserve was identified as E. annetteae based on morphometrics and morphology especially the simple morphology of the vagina, the absence of males, the cephalic setae being shorter than one third of the head width and two overlapping tooth pockets. Specimens found in Telperion Nature Reserve matches those from the type description as well as other described populations of E. annetteae . The Telperion Nature Reserve population was compared to the type population in Joubert & Heyns (1979) as well as the populations in Botha & Heyns (1992); Eyualem-Abebe & Coomans (1995) and Yunliang & Coomans (2000). The Telperion Nature Reserve population differs from the type population in the following aspects: slightly shorter body (1049–1547 μm vs 1400–1700 μm), shorter cephalic setae (4–6 μm vs 7–10.5 μm), narrower stoma (6.3–11 μm vs 14.9 μm). However, Botha & Heyns (1992) stated that this measurement of the stoma width was incorrect and measured the type material at 8.6 μm. Based on the morphometrics and morphology of other E. annetteae populations the Telperion Nature Reserve population falls within the range of the species, matching the morphology and morphometrics of all known populations except in the vagina length as percentage of corresponding body width (25–46 vs 54–64). The population from Telperion Nature Reserve is most similar to the populations of the Galápagos in Eyualem-Abebe & Coomans (1995). The morphometrics together with the South African origin and geographical distribution of this species, support the identification of the Telperion Nature Reserve Eutobrilus population as E. annetteae .

Locality and material examined: Specimens of E. annetteae were found at three sites i.e. river site (MP00038); wetland site (MP00013) and waterhole (MP00091) ( Table 1 ) and are deposited in the National Collection of Nematodes (ARC—Plant Health and Protection, Biosystematics, Pretoria) on slide numbers 50564,50565; 50574; 50577,50585.

Figures

FIGURE 11. Female drawings Eutobrilus annetteae (Joubert & Heyns, 1979) Tsalolikhin, 1983 A) Head region showing structure of stoma and tooth pockets; B) Anterior region showing oesophagus; C) Vulval region and genital tract; D) Tail.

FIGURE 12. Scanning electron micrograph of Eutobrilus annetteae (Joubert & Heyns, 1979) Tsalolikhin, 1983; A) Anterior end showing long cephalic setae (lcs), short cephalic setae (scs) and labial papillae (lp) and liplets (l); B) Ventral side of body showing vulva (arrow); C) Tail region showing spinneret (arrow).

FIGURE 13. Light microscopic pictures of Eutobrilus annetteae (Joubert & Heyns, 1979) Tsalolikhin, 1983 female A) Anterior region indicating buccal cavity to cardia; B) Whole female specimen, arrow indicating vulva; C) Vulval region showing simple vaginal musculature; D) Labial region showing buccal cavity and two overlapping tooth pockets (T1 and T2).