Geomonhystera ecuatoriana, Prado-Vera & Ferris & Subbotin, 2018

Prado-Vera, Ignacio Cid Del, Ferris, Howard & Subbotin, Sergei A., 2018, Six new and one known species of Geomonhystera (Nematoda, Monhysteridae) from moss, an epiphytic plant and soil in México and Ecuador, Zootaxa 4471 (1), pp. 76-110 : 88-89

Geomonhystera ecuatoriana sp. n.

( Fig. 7 A–H ; Fig. 8 A–D )

Measurements. Tables 2, 3 and 4.

Female (n=3): Body sigmoid or curved ventrally after fixation; cuticle I–2 µm thick, with very fine striation; body with a few thin setae, 3–4 µm long, mainly in cervical region and in vulva-anus area; no setae observed on tail; head 11–12 (11.3 ±0.6) µm wide and 3 µm high; lips triangular, fused at the base and clearly separated distally; inner labial papillae very small, coniform, 2 µm long; outer labial setae unsegmented, 5–6 (5.3±0.6) µm long or 42–55 (47±6.6) % of head width; cephalic setae thin, 4–5 (4.3±0.6) µm long and 33–46 (38±6.3) % of head width; amphid foveae rounded, 4 µm diameter and 13–18 (16±2.7) µm from anterior margin to anterior of head, both amphids at the same level; pharynx muscular,113–152 (139±23) µm long; nerve ring at 55–77 (68±11.7) µm from the anterior end; cardia valve 5–10 (7.5±3.5) µm long and 7–10 (8.5±2.1) µm wide; rectum muscular, 25–30 (27±2.7) µm long and 1.3–1.6 (1.4±0.2) times the anal body diameter; anterior anus lip slightly protruding. Gonad (n=1) 330 µm long, ovary short with one row of oocytes, 34% of body length, vulva to anus distance 37–48 (41±5.9) µm or 2.1–2.5 (2.2±0.3) times the anal body diameter; vulval lips slightly protruding; vagina with slightly thickened walls, 7.0–10 (8.7±1.5) µm long, post-vulval uterine sac absent; tail tapering evenly, straight or slightly curved ventrally,103–112 (106.7±4.7) µm long or 12–14 (12.8±1.1) % of the body length, with a few setae; three caudal glands, posterior to the anus and in line, ducted to a common ampulla, 6–10 (8.0±2.0) µm long and then to a conspicuous, terminal spinneret, 2–3 µm long.

Male (n=1): Body of relaxed specimen slightly wave-shaped after fixation; cuticle 2 µm thick, with very fine transverse striation; body with few setae; head 11 µm wide and 3 µm high; lips fused; inner labial papillae very small, coniform; outer labial setae unsegmented, 5 µm in length or 45.5% of head width; cephalic setae thin, 4 µm in length and 36% of head width; amphid foveae rounded, 4 µm diameter, anterior edge 18 µm from the head end, both amphids at the same level; pharynx muscular, 137 µm long; nerve ring at 69 µm from the anterior end; cardia 5 µm long and 10 µm wide, composed of conspicuous cells. In the ventral precloacal region is a series of 38 papilloid cuticular folds. Copulatory spicules equal in length, slightly arcuate, 35 µm long or about 1.5 times cloacal body diameter and non-cephalate with acute tips; gubernaculum 8 µm long; tail with a few thin setae, 110 µm long or 12.2% of body length and 24 µm wide, ending in a terminal spinneret 2 µm long. Caudal glands not seen.

Diagnosis and relationships. Geomonhystera ecuatoriana sp. n. has fine cuticular striation and a few thin body setae; the outer labial setae, which are unsegmented, are 42–54% of the head width and the cephalic setae are thin, unsegmented, 33–45% of the head width; vulval lips slightly protruding; vulva-anus distance 37–48 µm or 2.1–2.5 times the anal body diameter; spinneret conspicuous, 2–3 µm long, with ampulla 6–10 µm long. Males with copulatory spicules of equal size, slightly arcuate, 35 µm long or about 1.5 times the cloacal body diameter.

Geomonhystera ecuatoriana sp. n. has cuticular striations that are finer than most of the other species of the genus in which the cuticle is striated; it is distinguished also by the length of the outer labial and cephalic setae which, in length, are <50% of head width. It is distinguished from those species in which males are present ( G. steineri ( Micoletzky, 1922) Andrássy, 1981 and G. villosa ( Bütschli, 1873) Andrássy, 1981 ) by the fine cuticle striation. It is close to G. steineri in the body length, very short body setae, and shape and length of the spicules but differs in the index c´, 5.5–5.9 (5.8) and 4.6 vs. 6–8 and 5.5–6.5 in females and males, respectively, in the relationship of outer labial setae to head width, 42–46 (44) vs. 50–56, the amphid diameter, 4 vs 1.0–1.5, in the somewhat greater the vulva-anus distance, 37–48 vs. 28–40, the tail length times the vulva-anus distance, 2.3–2.8 (2.6) vs. 3–4. Geomonhystera ecuatoriana sp. n. differs from G. villosa in the index c´, 5.5–5.9 vs. 7–9, in the few, small vs. abundant, longer body setae, and the length of the rectum relative to the anal body diameter, 1.3–1.6 vs. 2.0–2.5.

Geomonhystera ecuatoriana sp. n. resembles G. dubia Siddiqi & Shahina, 2004 and G. pervaga ( Argo and Heyns, 1973) Andrássy, 1981 in the fine striation of the cuticle and in the position of the vulva. It differs from G. dubia in the body length, 0.49–0.55 vs. 0.7-1.0 mm, the length of the rectum, 26-30 vs. 20-24 µm, the length of the tail, 103–112 (107±4.7) vs. 57–77 (69) µm, in the length of the pharynx, 113–152 (139) vs. 102–120 (115) µm. The new species differs from G. pervaga in the index b, 6.3-6.6 (6.5) vs. 4.5-5.5 (4.9), c’, 5.7-5.9 (5.8) vs. 6.4-7.4 (7.1), the length of the outer labial setae, 5 vs. 6-11 µm, in the amphid to head/head width, 1.2-1.5 (1.3) vs. <1, and the vulva to anus distance vs. anal body diameter, 2.1-2.5 (2.2) vs. 1.9.

Type locality and habitat. Moss on trunk of native trees, Scalesia pedunculata Hook. , f., on the twin volcanoes in the Parque Nacional Galapagos, of Isla Santa Cruz , Galapagos, Ecuador, 0° 37′ 33″ S 90° 23′ 04.7″ W, elevation 800 m asl., collected September 28, 2010 .

Type specimens. Holotype female on slide 10391, allotype male on slide 10392 and one paratype female on slide 10393 deposited in CNHE. One paratype is deposited in CPNC on slide number A-103.

Etymology. The name of the species comes recognizes the country in which the specimens were collected.

Figures

FIGURE 7. Geomonhystera ecuatoriana sp. n. Female (A, B, E, F, G, H). A: Anterior end body. B, E: Vulva-anus region; F: Posterior end body; G: Spinneret; H: Entire body. Male (C, D). C: Anterior end; D: Cloacal region.

FIGURE 8. Geomonhystera ecuatoriana sp. n. scanning electron micrographs; Female (A–D). A: Anterior end, lateral view. B: Head region, antero-lateral view. C: Anal region, ventral view; D: Tail, ventral view.