Geomonhystera longispiculata, 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 : 85-88

Geomonhystera longispiculata sp. n.

( Fig. 4 A–I ; Fig. 5 A–D ; Fig. 6 A–D )

Measurements. Tables 2, 3 and 4.

Female (n=7). Body slightly curved, tail curved ventrally after fixation. Cuticle 1 µm thick with conspicuous fine striation. Somatic setae scattered along the body. Cephalic region slightly convex, rounded in some specimens, 11–15 (14±1.5) µm wide. Lips triangular, fused at the base and clearly separated distally. Inner labial papillae conical, 2.0 µm long, outer labial setae unsegmented, 5–7 (5.9±0.7) µm long and 13–18 (14±1.8) % and 33–55 (42±7.3) % of head width respectively. Cephalic setae thinner, 3–5 (4.4±0.8) µm long and 21–39 (32±5.9) % of head width. Stoma funnel shaped. Amphidial fovea circular, 5.0 µm diameter, 17–26 (23±3.1) µm from anterior border to anterior of body. Pharynx a muscular tube, slightly expanded near posterior end, 160–182 (172±8.4) µm long. Nerve ring in the anterior part of the pharynx at 60–89 (76±11.4) µm from the anterior end. Cardia coneshaped, 5–13 (9±2.9) µm long and 8–14 (10±1.9) µm wide. Rectum 29–35 (33±2.4) µm long and 0.6–1.8 (1.3±0.5) times anal body diameter. Gonad (n=2) 424–726 (575±213) µm long, ovary short, 42–68 (55±18) % of body length, with one or two rows of oocytes. Vagina short, 8–15 (11.6±2.8) µm long, bent anteriorly. Vulval lips protruding; vulva-anus distance 34–51 (44±6.0) µm or 1.8–2.4 (2.2±0.2) times anal body diameter. Tail ventrally arcuate, 94–136 (112±13.5) µm long or 9.2–14 (11.5±1.4) % of the body length, with a few caudal setae. Three caudal glands arranged in tandem, with ducts terminating in a common ampulla, 9–11 (10.4±0.8) µm long, opening through a blunt-ended, terminal, spinneret, 2–3 (2.1±0.4) µm long.

Male (n=9). Body slightly curved, tail strongly curved ventrally after fixation. Cuticle very thin, 1 µm, with conspicuous fine striation and scattered setae. The somatic setae are thin and in latero-ventral and latero-dorsal positions. Cephalic region low, slightly convex and rounded in some specimens, 12–16 (14.6±1.2) µm wide. Inner labial papillae conical, 2.0 µm long. Outer labial setae unsegmented, 5–8 (6.3±0.9) µm long and 36–58 (44±6.7) % of head width. Four cephalic setae, thinner, 4–5 (4.8±0.4) µm long and 27–42 (33±4.4) % of head width. Amphidial fovea circular, 5.0 µm diameter, anterior border 22–27 (24±1.5) µm from anterior of body. Pharynx a muscular tube slightly expanded near posterior end, 152–191 (171±11.1) µm long. Nerve ring in the anterior part of the pharynx, 70–87 (80±6.7) µm from the anterior end. Cardia cone-shaped, 5–13 (8.6±2.2) µm long and 7–11 (9.2±1.2) µm wide. Testis outstretched, 600–655 (625±22.7) µm long and 52–61 (59±4.6) % of total body length. Spermatozoa oval shape, 8–9 µm long. Spicules slender, 55–85 (75±9.0) µm long; gubernaculum 8–11 (9.8±0.8) µm long, slightly ventrally curved, with rounded distal tip. In the ventral precloacal region is a series of 39–57 papilloid cuticular folds. Tail ventrally arcuate, 114–142 (128±10.1) µm long or 11–13 (12±0.6) % of body length, with three large caudal glands ducted into an ampulla, 10–12 (11.2±1.0) µm long, and then through a 3 µm long, blunt-ended spinneret.

Diagnosis and relationships. Geomonhystera longispiculata sp. n. is distinguished from all the species of the genus with males by the long, 55–85 (75±9.0) µm, slender spicules. The new species is also characterized by the conspicuous fine cuticular striation and somatic setae scattered along the body.

Geomonhystera longispiculata sp. n. resembles G. antarcticola Andrássy, 1998 , in the fine striation of the cuticle, in the body length of males, in the rounded distal tip of the gubernaculum and in the presence of scattered body setae. It differs in the length of the spicules, 55–85 (75±8.9) vs. 35 µm, in the index a, 29–40 (37±3.7) vs. 38– 46, in the shorter body length of females, 0.7–1.1 (0.98) vs. 1.1–1.3 mm, in the rectum length/anal body diameter, 0.6–1.8 (1.3) vs. 3 in G. antarcticola . It is also close to G. villosa ( Bütschli, 1873) Andrássy, 1981 , in the body length of both females and males, in the index a, in the distance from the amphid to anterior of the body. It differs from G. villosa in the length of the spicules, 55–85 (75±8.9) vs. 30–33 µm, in the smaller value of c’, 4.8–7.2 (5.8) vs. 7–9, in the shorter outer labial setae, 5.0–7.0 (5.9) vs. 12 µm, in the shorter cephalic setae, 3.0–5.0 (4.4) vs. 6 µm, in the smaller value or rectum/anal body diameter, 0.6–1.8 (1.3) vs. 2.0–2.5, in the finely-striated vs. smooth cuticle, in the presence of a few vs. several body setae, and in the rounded distal tip vs. forked end of the gubernaculum. The D2–D3 of 28S rRNA gene sequence of G. longispiculata sp. n. differed by 8.4–8.5% (60–61 bp) from those of G. mexiquense sp. n.

Type locality and habitat. Collected on March 6, 2015, from a filamentous epicphyte, Misodendrum sp. ( Misodendraceae ) growing on a tree in the Botanical Garden of the Ecology Institute of Jalapa, Veracruz, México, 19°30'47.4" N 96°56'32.9” W, elevation 1400 m asl.

Type specimens. Holotype female on slide 10388; allotype male on slide 10389, five paratype females on slide 10390 in CNHE. Other type material is deposited in the UCRNC on slide number 28541, WaNeCo slide number WT3718, and CPNC on slide number A-099.

Etymology. The species name is based on the length of the spicules.

Figures

FIGURE 4. Geomonhystera longispiculata sp. n.; Female (A, B, D, E, H). A, B: Anterior end body; D: Posterior end body; E: Pharyngeo-intestinal junction; H: Vulva-anus region. Male (C, F, I). C: Anterior end body; F: Posterior end body; I: Cloacal region. G: Body shape, females and males.

FIGURE 5. Geomonhystera longispiculata sp. n. scanning electron micrographs; Female (A–D). A: Face view; B: Posterior end, vulva and anus, ventral view; C: Tail lateral view; D: Spinneret.

FIGURE 6. Geomonhystera longispiculata sp. n. scanning electron micrographs; Male (A–D). A: Somatic setae, lateral view; B: Precloacal region, papilloid cuticular folds; C: Close up papilloid cuticular folds, lateral view; D: Cloaca and precloacal papilloid cuticular folds, latero-ventral view.