Klossnema viguerasi, Morffe & García & Hasegawa & Breugelmans, 2021

Morffe, Jans, García, Nayla, Hasegawa, Koichi & Breugelmans, Karin, 2021, Morphological and molecular characterization of Klossnema viguerasi n. sp (Nematoda: Oxyuridomorpha: Hystrignathidae) from a Cuban passalid beetle (Coleoptera: Passalidae), first record of the genus for Cuba, Zootaxa 4933 (3), pp. 391-402 : 394-399

Klossnema viguerasi n. sp.

Fig. 1 A–E, Fig. 2 A–F, Fig. 3 A–H

Type material. Holotype: ♀, Cuba, Artemisa province, Sierra del Rosario, Soroa ; 22°48′00″N, 83°01′00″W; in Antillanax pertyi ; II/2018; M. Iturriaga coll.; CZACC 11.7283 . Paratypes: 9♀♀, same data as the holotype; CZACC 11.7284 –11.7292 . 12³³, same data as the holotype; CZACC 11.7293 –11.7304 .

Other examined material. Vouchers: 9♀♀, Cuba, Sancti Spíritus province, Trinidad, Topes de Collantes, path to the Caburní River ; 21º53′41′′N, 79º54′20′′W ; in Antillanax pertyi ; 12/X/2014; J. Morffe, N. García coll.; CZACC 11.7309 –11.7317 . 8³³, same data as the latter; CZACC 11.7318 –11.7325 .

Vouchers: 7♀♀, Cuba, Guantánamo province, El Salvador, Limonar ; 20°12′34″N, 75°13′23″W; in Antillanax pertyi ; VI/2013; J. Morffe, N. García, M. Olcha coll.; CZACC 11.7326–11.7332 . 6³³, same data as the latter; CZACC 11.7333 –11.7338 .

Measurements. See Table 2.

Description. General. Small nematodes, body comparatively slender, ventrally curved in heat-fixed specimens. Cephalic end bluntly rounded, followed by the body diameter slightly increasing, keeping almost constant diameter towards the body length and gradually decreasing near tail level towards posterior end. Cephalic capsule smooth, dorsoventrally compressed. Mouth hexagonal, laterally orientated, with sides arranged as one dorsal, one ventral, two sub-dorsal and two sub-ventral. Mouth surrounded by six labia, each of them coinciding with one of its sides. Labia set-off from each other by short cleavages coinciding with the mouth edges. Four flat, elongated cephalic papillae present, arranged as one dorsal pair and one ventral. Papillae of each pair touching dorsally and ventrally, respectively, forming obtuse angles. Digitiform structure ca. 2 µm in length present close to each lateral edge of the mouth. Cuticle unarmed, finely annulated (annuli ca. 0.5 µm) from the base of the cephalic capsule to the base of the tail. Lateral alae absent. Oesophagus with a muscular, sub-cylindrical procorpus, its base slightly dilated. Isthmus comparatively long, ca. one third of the procorpus length. Basal bulb pyriform, valve plate well-developed. Intestine simple, sub-rectilinear, anterior portion barely dilated. Nerve ring encircling procorpus at its posterior half, ca. 60% of its length. Excretory pore ventral.

Female. Cuticle finely annulated from base of the cephalic capsule to level of anus. Rectum short, anus slightly prominent. Excretory pore ventral, located at ca. a body-width posterior the basal bulb. Vulva a ventro-median transverse slit, displaced to the posterior half of body, at ca. 60% of the body-length, lips slightly prominent. Genital tract monodelphic-prodelphic. Ovary unreflexed, its distal tip located at ca. 1–3 body-widths posterior to the excretory pore. Oocytes in single rows. Eggs ellipsoidal in shape, smooth-shelled. Gravid females with a single egg in the uterus, rarely two or three. Tail very short and subulate, sometimes curved in a hook-like appearance, ending in a sharp tip.

Male. Body smaller and slightly less robust than females, posterior end ventrally curved. Cuticle finely annulated from base of cephalic capsule to beginning of dorsal cuticular thickening of posterior end. Excretory pore ventral, located at ca. 1.5 body-widths posterior the basal bulb. Monorchic. Testis ventral, outstretched, commencing at a distance of ca. seven body-widths posterior to the excretory pore. Vas deferens with three distinguishable regions: an anterior region (occupying ca. 40% of the testis length) slender, with granular content and swollen in its joint with a median region (occupying ca. one third of the testis length) with large, rounded cells, and a posterior region that diminishes its diameter through the cloaca. Spicule absent. Tail very short, conoid, its tip sharp. Dorsal cuticle of tail end thickened and smooth, from ca. half of the level of the lateral pre-cloacal papillae to the tail tip. Six copulatory papillae, four pre-cloacal and two post-cloacal. First pre-cloacal pair consists of a ventromedian duplex papillae, very close to each other on a protuberance (appearing to be a single papilla in lateral view) located at ca. 40 µm from the cloaca. Sensilla of each papilla of this pair surrounded by peg-like prominences, arranged in ca. five circles more or less concentric. Second pair of pre-cloacal papillae formed by large peg-like papillae, lateral in position, located at a short distance (ca. 5 µm) before the level of the cloaca. One pair of post-cloacal papillae: a sub-lateral pair of minute papillae sub-terminal, near tail tip (ca. 1 µm). Phasmids pore-like, located at tail tip, very close to each other.

Differential diagnosis. Cordeiro & Artigas (1983) only offered the mean of the measurements of K. repentina . Therefore, we use these values for comparison with the new species. The females of K. viguerasi n. sp. are morphologically quite similar and only slightly longer than K. repentina (1.143 mm vs. 1.000 mm). However, several meristic variables are higher in K. viguerasi n. sp., namely the length of the procorpus (139 µm vs. 110 µm), the length of the isthmus (39 µm vs. 24 µm), the distance from the vulva to the anterior end (0.748 mm vs. 0.650 mm) and the tail length (28 µm vs. 21 µm). The males of K. viguerasi n. sp. are also larger than K. repentina (0.980 mm vs. 0.800 mm), but their isthmus is shorter (38 µm vs. 48 µm).

Type locality. Soroa , Sierra del Rosario, Candelaria municipality, Artemisa province, Cuba .

Other localities. Path to the Caburní river, Gran Parque Natural Topes de Collantes, Trinidad municipality, Sancti Spíritus province, Cuba; Limonar, El Salvador municipality, Guantánamo province, Cuba.

Type host. Antillanax pertyi (Kaup, 1869) ( Coleoptera : Passalidae ).

Site. Hind gut.

Etymology. Specific epithet dedicated to Ildefonso Pérez Vigueras (1892–1959) eminent Cuban veterinarian and parasitologist, and pioneer in studies of parasitic helminths from Cuban fauna, including invertebrates.

DNA studies. One partial sequence (806 bp) of the D2–D3 region of the 28S rDNA and one partial sequence (813 bp) of the 18S rDNA were obtained from females of K. viguerasi n. sp. The length of the 28S rDNA and the 18S rDNA datasets, once the poorly aligned regions and gaps were removed was of 738 bp and 725 bp, respectively. The concatenated dataset of both markers resulted in a 1463 bp aligment.

ML and BI phylograms of the concatenated dataset depict Klossnema viguerasi n. sp. as sister taxon to Tuhmai garciaprietoi Garduño-Montes de Oca & Oceguera-Figueroa, 2020, but with low nodal support. The aforementioned clade of Klossnema + Tuhmai is part of a larger clade containing Xyo and Longior ( Fig. 4 ).

Figures

FIGURE 1. Klossnema viguerasi n. sp. Female. A. Oesophageal region, lateral view. B. Tail, lateral view. C. Genital tract, lateral view. D. Egg. E. Habitus, lateral view.

FIGURE 2. Klossnema viguerasi n. sp. Male.A. Oesophageal region, lateral view. B. Cephalic end, en face view (reconstructed from SEM images). C. Tail, lateral view. D. Tail end, ventral view (reconstructed from SEM images). E. Detail of the tail tip, ventral view (reconstructed from SEM images). F. Habitus, lateral view.

FIGURE 3. Klossnema viguerasi n. sp., SEM images. Male. A. Cephalic end. B. Cephalic end, en face view. C. Tail, lateral view. D. Tail, ventro-lateral view. E. Detail of the tail, lateral view. F. Detail of the tail, ventral view. G. Ventromedian papilla, ventral view. H. Tail tip, ventral view. Scale bars: A, B, F. 2 µm. C, D. 10 µm. E. 5 µm. G, H. 1 µm.

FIGURE 4. Maximum likelihood (ML) tree inferred from a concatenated dataset of the D2–D3 28S rDNA and the 18S rDNA for several species of the family Hystrignathidae (Nematoda: Oxyuridomorpha: Thelastomatoidea). One species of Travassosinema (Travassosinematidae) was used as outgroup taxon. Values at the nodes correspond to ML bootstrap resampling (±70)/ Bayesian posterior probability (±0.90).