Longior lamothei, 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 : 133-139

Longior lamothei n. sp.

Fig. 4 A–G, Fig. 5 A–D, Fig. 8 A–C

Type material. ♀ holotype, Mexico, Michoacán, Uruapan municipality, Cerro de Jicalán ; 19º23’39’’N, 102º04’31’’W ; in Passalus punctiger ; 24/VII/2014; L. F. de Armas, J. Ponce, A. Quijano , R. Teruel coll.; CZACC 11.7170 . Paratypes 3♀♀, same data as holotype, CZACC 11.7171 –11.7173 ; 2♂♂, same data as holotype, CZACC 11.7174 –11.7175 .

Other material. Vouchers 6♀♀, Colombia, César, Sierra Nevada de Santa Marta, Chemesquemena ; 10°42’N, 73°23’W; 6/VII/2007 ; L. Jiménez-Ferbans, A. Mejía coll.; CZACC 11.7176 –11.7181 ; 2♂♂, same data as the latter, CZACC 11.7182 –11.7183 .

Vouchers 5♀♀, Colombia, Tolima, Cunday, footpath to Cueva del Edén ; 4°00’718’’N, 74°45’309’’ W; 11/ XI/2011; D. Luna, A. García coll.; CZACC 11.7184 –11.7188 ; 9♂♂, same data as the latter, CZACC 11.7189 – 11.7197 .

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 annuli (ca. 10 µm) from the base of the first cephalic annule to ca. the level of the first quarter of procorpus. Lateral alae well-developed, extending from ca. three body-widths (a distance of ca. a body-width before the vulva) 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 surrounds the trirradiate oral opening. Amphids lateral, at level of the base of the cephalic papillae. First cephalic annule comparatively long, truncate, slightly dilated, ca. 1.2–2 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. 30% of its length. Excretory pore ventral, located just posterior to the basal bulb. Vulva a median transverse slit, its lips not prominent, located at level of midbody. Vagina muscular, forwardly directed. Genital tract monodelphic-prodelphic, occupying ca. 35% of the body length. Distal end of the ovary reflexed at ca. one body-width posterior to the excretory pore, distal flexure ca. 2.5 body-widths 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 3– 5 eggs at a time in the uterus. Phasmids barely evident, pore-like, lateral, located at a short distance (ca. 5 µm) posterior to the level of the anus. 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 the level of 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, extend 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. Oesophagus consists of a muscular, sub-cylindrical procorpus, its diameter diminishing towards its posterior half, almost equaling the diameter of the cylindrical isthmus at the level of their junction. 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 a short distance (ca. 25 µm) 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 bursalike structure present at the cloaca. 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. Such thickening forms a cuticular crest at the tail tip that extends terminally and laterally until the level of the distal end of the bursa. Four pairs of copulatory papillae, two pre-cloacal and two post-cloacal. A large pair of ventromedian pre-cloacal, duplex papillae situated very close to each other on an ellipsoidal protuberance (appearing as a single papilla in lateral view) at ca. 120 µm from the tail tip. One sub-lateral pre-cloacal pair of papillae at ca. 60 µm from the tail tip. First post-cloacal pair consisting 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, and located below the terminal cuticular crest.

Differential diagnosis. The females of L. lamothei n. sp. differ from L. semialata by its more extended lateral alae, from ca. three body-widths posterior to the basal bulb to the level of the anus in opposition to lateral alae that extend from the level of the vulva to the level of the anus ( Hunt 1981). Also, the body of L. lamothei n. sp. is more robust than L. semialata (a = 14.20–16.33 vs. 18.10–20.40) and its vulva is more anterior (V% = 43.46–51.17 vs. 51.80–57.60).

Longior lamothei n. sp. is shorter than L. longicollis and L. zumpimito n. sp. (2.130 –2.830 mm vs. 2.980 –3.640 mm vs. 3.110 –3.920 mm) but its tail is comparatively longer (c = 5.57–6.35 vs. 9.03–9.33 vs. 7.93–9.58). The vulva of L. longicollis is more posterior than that of L. lamothei n. sp. (V% = 57.72–61.81 vs. 43.46–51.17) ( Travassos & Kloss 1958). Longior elieri and L. panamensis present the smallest females among the genus ( García et al. 2009; Morffe & García 2012) and are shorter than L. lamothei n. sp. (1.650 –1.950 mm vs. 1.67–2.06 mm vs. 2.130 –2.830 mm). The body of L. lamothei n. sp. is more robust than L. elieri (a = 14.20–16.33 vs. 17.11–18.44) and the tail is comparatively shorter (c = 5.57–6.35 vs. 5.00–5.34).

Longior lamothei n. sp. is shorter than L. longior (2.130 –2.830 mm vs. 3.500 –4.525 mm), its body is more robust (a = 14.20–16.33 vs. 23.61–28.28) and its oesophagus comparatively longer (b = 3.67–4.42 vs. 4.49–5.45). Moreover, in L. lamothei n. sp. the female genital tract comprises ca. 35% of the body instead of ca. 20% in L. longior .

Longior lamothei n. sp. is similar in length to L. similis and L. surieli n. sp. (2.130 –2.830 mm vs. 2.675 –3.075 mm vs. 2.550–2.85 mm). It differs from L. similis in having a more robust body (a = 14.20–16.33 vs. 16.88–22.50) and the vulva more anterior (V% = 43.46–51.17 vs. 51.22–53.70). The excretory pore of L. lamothei n. sp. is located just posterior the basal bulb in opposition to L. surieli n. sp., with the excretory pore located at ca. the half of a body-width posterior the basal bulb. Also, the reproductive system of L. lamothei n. sp. comprises ca. the 35% of the body length instead ca. the 30% in L. surieli n. sp.

The males of L. lamothei n. sp. are among the shortest of the genus and this feature contributes to differentiating them from most of the species with known males, namely L. longior , L. longicollis , L. surieli n. sp. and L. zumpimito n. sp. (0.850 –1.030 mm vs. 1.075 –1.590 mm vs. 1.380 –1.970 mm vs. 1.000 –1.550 mm vs. 1.250 –1.380 mm). Longior lamothei n. sp. also present the oesophagus (b = 3.70–3.75 vs. 3.79–3.97) and the tail (c = 38.00–46.00 vs. 62.5–72.00) comparatively longer than L. zumpimito n. sp. The oesophagus of L. longior is comparatively larger than that of L. lamothei n. sp. (b = 3.13–3.63 vs. 3.70–3.75). The tail of L. longicollis is comparatively larger than L. lamothei n. sp. (b = 30.66–32.83 vs. 38.00–46.00) and its body is more slender (a = 21.65–23.79 vs. 12.88–14.17). The males of L. surieli n. sp. present a characteristic swelling of a group of cuticular annuli next to the head that is absent in L. lamothei n. sp.

Longior lamothei n. sp. and L. similis are similar in body length (0.850 –1.030 mm vs. 0.860 –1.370 mm), but they differ in the position of the nerve ring: in the new species it encircles the procorpus at ca. 35% of its length, while in L. similis it is more posterior, at ca. 45%. Additionally, the excretory pore is notably more posterior in L. lamothei n. sp., ca. 1.5–2 body-widths behind the basal bulb instead of ca. a body-width in L. similis .

Type locality. Cerro de Jicalán , Uruapan municipality, Michoacán, Mexico .

Other localities. Chemesquemena, Sierra Nevada de Santa Marta, César, Colombia; footpath to Cueva del Edén, Cunday, Tolima, Colombia.

Type host. Passalus punctiger Le Peletier & Serville, 1825 ( Coleoptera : Passalidae ).

Site. Hind gut.

Etymology. Species named after the eminent Mexican parasitologist Rafael Lamothe-Argumedo (1932–2013). This is an homage to his contributions to the knowledge of the taxonomy of the helminths from the Neotropics as well as the formation and development of the helminthological collections.

Figures

FIGURE 4. Longior lamothei n. sp. Female. A. Oesophageal region, lateral view. B. Cephalic end, optical section. C. Cephalic end, external view (reconstructed from SEM images). D. Tail, lateral view. E. Egg. F. Genital tract, lateral view. G. Habitus, lateral view.

FIGURE 5. Longior lamothei n. sp. Male. A. Oesophageal region, lateral view. B. Cephalic end, optical section. C. Tail, lateral view. D. 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.