Longior zumpimito, Morffe & García & Adams & Hasegawa, 2020

Morffe, Jans, García, Nayla, Adams, Byron J. & Hasegawa, Koichi, 2020, Three new species of Longior Travassos & Kloss, 1958 (Nematoda Thelastomatoidea: Hystrignathidae) parasites of passalid beetles (Coleoptera Passalidae) from Dominican Republic, Mexico and Colombia, Zootaxa 4877 (1), pp. 125-147 : 139-145

Longior zumpimito n. sp.

Fig. 6 A–G, Fig. 7 A–F, Fig. 8 D–F

Type material. ♀ holotype, Mexico, Michoacán, Uruapan municipality, Zumpimito Hydroelectric Plant ; 19º22’44’’N, 102º04’11’’W ; in Passalus punctatostriatus ; 24/VII/2014; L. F. de Armas, J. Ponce, A. Quijano , R. Teruel coll.; CZACC 11.7198 . Paratypes 8♀♀, same data as holotype, CZACC 11.7199 –11.7206 ; 3♂♂, same data as holotype, CZACC 11.7207 –11.7209 .

Description. Female. Body long and comparatively slender, widening gradually posterior to head, reaching its maximum width at level of the vulva, then narrowing gradually towards tail. Cuticle thin. Sub-cuticular striae present. Cervical cuticle unarmed, with wide, barely conspicuous annuli (ca. 5–11 µm) from the base of the first cephalic annule to a short distance before the level of the nerve ring. Lateral alae well-developed, extending from ca. 1–1.5 body-widths posterior to the basal bulb to the level of the anus. Head bearing eight paired, digitiform cephalic papillae arising from the external edge of head, at ca. half of its height. A cuticular, veliform annular lip surrounding the trirradiate oral opening. Amphids lateral, at level of the base of the cephalic papillae. First cephalic annule comparatively long, truncate, slightly dilated, ca. two head-lengths long. Stoma long and slender, surrounded by an oesophageal collar. Oesophagus consists of a muscular, sub-cylindrical procorpus, its base similar in diameter to the isthmus. Basal bulb pyriform, valve-plate well-developed. Intestine simple, sub-rectilinear, its fore region slightly dilated. Rectum comparatively long. Anus as a crescent-like ventromedian slit, anteriorly directed, not prominent. Nerve ring encircling procorpus at ca. 25% of its length. Excretory pore located at ca. 0.5–0.7 body-width posterior to the basal bulb. Vulva a median transverse slit, its lips slightly prominent, located at level of midbody. Vagina muscular, forwardly directed. Genital tract monodelphic-prodelphic, occupying ca. 34% of the body length. Distal end of the ovary reflexed at ca. 1–1.5 body-widths posterior to the excretory pore, distal flexure ca. one body-width long. Oocytes in a single row. Eggs ellipsoidal, bearing eight rough, prominent longitudinal ridges in the shell that do not reach the poles. Gravid females with 1– 5 eggs (more frequently 3–5) at a time in the uterus. Tail conical, subulate, ending in a fine tip.

Male. Body comparatively shorter and more slender than females. Posterior region ventrally curved. Cervical cuticle unarmed, markedly annulated up to a little distance before the nerve ring, annuli ca. 2 µm. Rest of body with less conspicuous annuli (ca. 1 µm), up to level of the dorsolateral pair of papillae. Lateral alae narrow, extending from the oesophageal region at level of the posterior half of procorpus to a short distance before the level of the median pair of copulatory papillae. Head set-off from body by a deep groove, bearing eight ellipsoidal, slightly flattened cephalic papillae; arranged as two sub-dorsal and two sub-ventral pairs. Six digitiform lips arise from the internal edge of the cephalic papillae and project to the center of the oral aperture. Lips are arranged as one dorsal lip, one ventral, two sub-dorsal and two sub-ventral. The sub-dorsal and sub-ventral lips flank the dorsal and ventral lips, respectively. Amphids lateral, crescent-like. Oesophagus consists of a muscular, sub-cylindrical procorpus. Basal bulb spherical, valve plate well evident. Intestine simple. Nerve ring encircling procorpus at ca. 40% of its length. Excretory pore ventral, located at ca. 0.5 body-widths posterior to the basal bulb. Monorchic. Testis outstretched, its distal end located at ca. a body-width behind the excretory pore. Vas deferens with three distinguishable regions: an anterior region with granular content; a median, slightly swollen region, also granular (granuli slightly shorter in diameter) and a posterior region that diminishes its diameter through the cloaca. Spicule absent. A bursa-like structure present at the cloaca. The tail tip presents a hammer-like appearance due to a ventral bending and a dorsal knob-like protuberance. Dorsal cuticle of the posterior end thickened and smooth from the tail tip to ca. the midpoint between the ventromedian pair of papillae and tail tip. Thickened end forms a cuticular crest at the tail tip that extends terminally and laterally. Phasmids pore-like, lateral, located at level of the first third of the bursa and at ca. 10 µm from the posterior end. Four pairs of copulatory papillae, two pre-cloacal and two post-cloacal. A large pair of ventro-medial pre-cloacal papillae in close proximity to each other located on an ellipsoidal protuberance (appearing as a single papilla in lateral view) at ca. 100 µm from the tail tip. One sub-lateral pre-cloacal pair of papillae at ca. 50–60 µm from the tail tip, near the level of the beginning of the dorsal cuticular thickening. First post-cloacal pair consists of small papillae, ventral, located at the tip of a papilliform protuberance just posterior to the bursa. Protuberance is posteriorly oriented. Last pair of post-cloacal papillae small, ventral, sub-terminal, close to the tail tip, located below the terminal cuticular crest.

Differential diagnosis. The females of L. zumpimito n. sp. can be differentiated from most of the nominal species of the genus by its body length (3.110 –3.920 mm), only similar to L. longior (3.500 –4.525 mm) and L. longicollis (2.980 –3.640 mm). In the rest of the species the female body length is under 3.000 mm, with the exception of L. similis (2.675 –3.075 mm). It differs from L. longior by having the body comparatively more robust (a = 18.10–22.64 vs. 23.61–28.28) and the genital tract occupying ca. 34% of the body length in opposition to ca. 20% in L. longior . Longior zumpimito n. sp. differs from L. longicollis by its more anterior vulva (V% = 49.86–54.89 vs. 57.72–61.81).

Longior zumpimito n. sp. can be differentiated from L. semialata by the extension of the lateral alae from a distance of 1–1.5 body-widths posterior to the basal bulb to the level of the anus in opposition to the lateral alae extending from the level of the vulva to the anus. The females of L. zumpimito n. sp. present the tail comparatively shorter than L. elieri , L. lamothei n. sp., L. similis , L. surieli n. sp. and L. panamensis (c = 7.93–9.58 vs. 5.00–5.34 vs. 5.57–6.35 vs. 6.22–6.99 vs. 5.31–5.83 vs. 5.42–6.30). Additionally, L. zumpimito n. sp. presents the oesophagus comparatively shorter than L. elieri and L. panamensis (b = 4.32–4.84 vs. 3.65–3.98 vs. 3.59–4.20). Both, L. lamothei n. sp. and L. surieli n. sp. are more robust than L. zumpimito n. sp. (a = 14.20–16.33 vs. 14.47–15.83 vs. 18.10–22.64).

The males of L. zumpimito n. sp. can be differentiated from L. longicollis by its shorter body (1.250 –1.380 mm vs. 1.380 –1.970 mm) and comparatively shorter tail (c = 62.50–72.00 vs. 30.66–32.83). L. zumpimito n. sp. differs from L. lamothei n. sp., L. longior and L. surieli n. sp. by its oesophagus (b = 3.79–3.97 vs. 3.70–3.75 vs. 3.13–3.63 vs. 2.94–3.75) and tail (c = 62.50–72.00 vs. 38.00–46.00 vs. 43.33–51.27 vs. 38.33–58.00) comparatively shorter. Moreover, L. zumpimito n. sp. present the tail comparatively shorter than L. similis (c = 62.50–72.00 vs. 36.40–60.50) and the excretory pore located slightly closer to the base of the basal bulb: ca. 0.5 body-widths in opposition to ca. a body width.

Type locality. Zumpimito Hydroelectric Plant , Uruapan municipality, Michoacán, Mexico .

Type host. Passalus punctatostriatus Percheron, 1835 ( Coleoptera : Passalidae ).

Site. Hind gut.

Etymology. Specific epithet in apposition after the type locality of the new species.

Figures

FIGURE 6. Longior zumpimito n. sp. Female. A. Oesophageal region, ventro-lateral view. B. Cephalic end, optical section. C. Cephalic end, en face view (reconstructed from SEM images). D. Tail, ventro-lateral view. E. Egg. F. Genital tract, ventro-lateral view. G. Habitus, ventro-lateral view.

FIGURE 7. Longior zumpimito n. sp. Male. A. Oesophageal region, lateral view. B. Cephalic end, optical section. C. Tail, lateral view. D. Tail end (reconstructed from SEM images). E. Ventro-median pair of pre-cloacal papillae, lateral view (reconstructed from SEM images). F. Habitus, lateral view.

FIGURE 8. Longior lamothei n. sp. SEM images. Female. A. Cervical region. B. Cephalic end, en face view. C. Tail end at level of the anus, showing the phasmid. Longior zumpimito n. sp. SEM images. Female. D. Cephalic end, en face view. Male. E. Tail, lateral view. F. Ventro-median pair of pre-cloacal papillae, lateral view. Scale bars: A. 40 mm. B, D, E. 5 µm. C. 10 µm. F. 2 µm.