Trachyglossoides jimenoi García & Morffe, 2015

García, Nayla & Morffe, Jans, 2015, A new genus and two new species of Xustrostomatidae Hunt, 2002 (Nematoda: Rhigonematomorpha) from the West Indies, Papéis Avulsos de Zoologia (São Paulo) 55 (6), pp. 91-101 : 96-97

Trachyglossoides jimenoi García & Morffe

gen. nov. sp. nov.

( Fig. 1 A-E, Fig. 2 A-D, Fig. 3 A-H)

Type material: ♀ holotype, Cuba, Mayabeque province, San José de Las Lajas, La Jaula , 82°06’00”N, 23°01’00”W; in Spirobollelus sp.; 18/II/2013; J. Morffe, N. García & M.A. Olcha coll.; CZACC 11.4715 . Paratypes 8 ♀♀, same data as holotype, CZACC 11.4716 -11.4723 ; 3 ♂♂, same data as holotype, CZACC 11.4724 -11.4726 ; ♀, same data as holotype, CHIOC ; ♂, same data as holotype, CHIOC ; ♀, same data as holotype, RIT 835 ; ♂, same data as holotype, RIT 836 .

Measurements

Holotype (female) a = 22.39, b = 16.12, c = 26.87, V% = 62.03, total length = 4.030, maximum body width = 0.180, corpus length = 0.148, isthmus length = 0.050, diameter of basal bulb = 0.070, total length of oesophagus = 0.250, nerve ring to anterior end = 0.198, excretory pore to anterior end = 0.210, vulva to posterior end = 1.530, vulval flap length = 0.048, tail length = 0.150, eggs = 0.105 -0.108 × 0.078 (0.106 ± 0.001 × 0.078, n = 3).

Paratypes (females) (n = 10) a = 21.89-30.75 (24.18 ± 2.60, n = 10), b = 13.91-16.77 (15.34 ± 0.93, n = 10), c = 18.94-35.20 (25.08 ± 4.75, n = 9), V% = 59.66-66.57 (63.62 ± 2.19, n = 10), total length = 3.270 -4.080 (3.690 ± 0.256, n = 10), maximum body width = 0.120 -0.180 (0.154 ± 0.018, n = 10), corpus length = 0.130 -0.163 (0.143 ± 0.009, n = 10), isthmus length = 0.030 -0.043 (0.037 ± 0.004, n = 10), diameter of basal bulb = 0.070 -0.083 (0.076 ± 0.004, n = 10), total length of oesophagus = 0.225 -0.255 (0.241 ± 0.009, n = 10), nerve ring to anterior end = 0.175 (n = 1), excretory pore to anteri- or end = 0.175 -0.188 (0.182 ± 0.006, n = 6), vulva to posterior end = 1.120 -1.490 (1.343 ± 0.129, n = 10), vulval flap length = 0.038 -0.050 (0.044 ± 0.006, n = 6), tail length = 0.100 -0.180 (0.151 ± 0.024, n = 9), eggs = 0.080 -0.108 × 0.065 -0.075 (0.094 ± 0.008 × 0.071 ± 0.004, n = 19).

Paratypes (males) (n = 5) a = 20.21-23.58 (22.32 ± 1.40, n = 5), b = 12.00-13.73 (12.89 ± 0.63, n = 5), c = 35.61-49.22 (41.77 ± 5.29, n = 5), total length = 2.760 -3.020 (2.892 ± 0.120, n = 5), maximum body width = 0.120 -0.140 (0.130 ± 0.010, n = 5), corpus length = 0.130 -0.140 (0.136 ± 0.004, n = 5), isthmus length = 0.035 -0.038 (0.037 ± 0.001, n = 5), diameter of basal bulb = 0.070 -0.075 (0.073 ± 0.003, n = 5), total length of oesophagus = 0.215 -0.235 (0.225 ± 0.008, n = 5), nerve ring to anterior end = 0.168 -0.185 (0.177 ± 0.006, n = 5), excretory pore to anterior end = 0.165 -0.175 (0.170 ± 0.005, n = 3), tail length = 0.058 -0.078 (0.070 ± 0.008, n = 5), spicule length (on chord) = 0.078 -0.093 (0.085 ± 0.005, n = 6).

Description

General: Cephalic end cuticularized, laterally compressed, consisting of a cephalic cap and a cephalic collar, both sub-terminal in position and ventrally displaced. The cephalic cap and cephalic collar are separated by a groove, wider and deeper in the dorsolateral sector and shallower in the ventrolateral sector. Amphids pore-like, dorsolateral, situated in the groove between the cephalic cap and the cephalic collar. Cephalic papillae very short, two sub-dorsal and two subventral. Cuticle finely annulated, covered with fine, dense microtricha, from the end of the cephalic collar to ca. the midpoint of body. The microtricha near the cephalic collar (dorsally, the ones that extends ca. two body widths further down the body and ventrally, the first two or three rows) are notably longer (ca. three times the length of the shorter microtricha located behind them). The shorter microtricha are as longer as the annuli (from ca. 1 µm at the anterior part of body to ca. 0.5 µm at midbody) and are arranged in alternate rows. Oral aperture sub-terminal, ventrally displaced, moderately elongated in a dorsoventral direction, its dorsal part slightly reduced and the ventral part with concave margin. Jaw-like apparatus modified as rasps, covered with very small spines arranged in opposite rows. Ventral rasp hypertrophied, forming a tongue-like structure inserted between two sub-dorsal rasps, not hypertrophied and embedded in the musculature of the oesophageal corpus. Pharynx with a hypertrophied corpus, very muscular and robust. Isthmus well developed, sub-cylindrical, almost as wide as the corpus, similar in length to the basal bulb. Basal bulb not hypertrophied, sub-spherical, cuticularised valve-plate present, cardias wide and short, projected into the intestine lumen. Intestine simple, sub-rectilinear, its fore region barely inflated. Nerve ring not evident, at level of the isthmus. Excretory pore ventrally situated, at level of the isthmus.

Female: Vulva displaced to the posterior half of body. Anterior lip of vulva hypertrophied, forming a short lobe, slightly inflated, triangular in shape. Posterior lip of vulva with recurved margin. Vagina compara- tively short and muscular. Vaginal diverticulum absent. Genital tract monodelphic-prodelphic, Type 1 after Adamson (1987). Ovary reflexed at ca. five body-widths posterior to the basal bulb. Distal flexure of the ovary very long, ca. 14 body-widths long. Oöcytes of the distal part of the ovary in two rows, in the rest of the ovary they are arranged in a single row. The ovary continues with a uterus that leads in the vagina. Eggs ellipsoidal in shape, shell smooth and more or less thin. A number of 10- 41 eggs at a time in the uterus. Tail comparatively short, attenuate, its tip rounded.

Male: Body shorter and less robust than females. Monorchic. Testis outstretched. Spicules isomorphic, almost isometric. Shafts ventrally arcuate. Capitulum not evident. Cuticle of the shafts smooth, not ornamented. Posterior end of body ventrally curved. Caudal alae well developed, sub-ventral, not lobate, extending from the tail tip to ca. 1.5 body-widths long. The posterior end of the caudal alae ending in a rounded lobe that extends to a short distance posterior to the tail tip. Nineteen copulatory papillae arranged as a median precloacal papilla and nine pairs situated on the caudal alae. Five pre-cloacal pairs, the first near the level of the cloaca; second and third pairs close to the first and equidistant from each other; fourth pair situated at ca. twice of the distance between the second and third pairs; fifth pair located at the end of the caudal alae, equidistant from both precedent pairs. A single pre-cloacal, median papilla located near the level of the third pre-cloacal pair. Post-cloacal papillae arranged in four equidistant pairs. Tail conical, short, its tip rounded, more or less digitiform.

Discussion: Trachyglossoides jimenoi gen. nov. sp. nov. is very close to Trachyglossus by the presence of a cephalic cap laterally compressed, the oral aperture dorsoventrally elongated, the plate of the jaw apparatus hypertrophied as a tongue-like structure, the corpus and isthmus also hypertrophied, the anterior lip of vulva well developed and lobed and the males with caudal alae. It differs from Trachyglossus by the slight compression of the cephalic cap and the comparatively reduced elongation of the oral aperture vs. the more marked of Trachyglossus ( Hunt, 2002) . The tonguelike structure is ventral in the new genus in opposition to the dorsal of Trachyglossus and shows less development. In addition, the vulval flap of the females is reduced to a short, triangular lobe in Trachyglossoides instead of the more extended lobe of the Congolese genus. The caudal alae are not lobed and more extended vs. lobed and shorter and the number and ar- rangement of the copulatory papillae also differ: 19 in Trachyglossoides and 23 in Trachyglossus .

Trachyglossoides jimenoi gen. nov. sp. nov. is the only monogonant xustrostomatid. The degree of the lateral compression of the cephalic cap as well as the dorso-ventral elongation of the oral aperture is less marked than in other genera in the family. It differs from Xustrostoma and Obainia by presenting the oesophageal corpus and the isthmus hypertrophied instead of the bulb as occurs in the latter genera ( Adamson, 1983; Adamson & Van Waerebeke, 1984). Also, it can be segregated by having a tongue-like plate in the jaw apparatus, a vulval flap, caudal alae in the males and a different number and arrangement of the copulatory papillae.

Both Trachyglossoides gen. nov. and Zalophora present the corpus hypertrophied but differ by the presence of an evident isthmus in Trachyglossoides gen. nov. in opposition to the corpus amalgamated with the basal bulb (also hypertrophied) in Zalophora . Trachyglossoides gen. nov. shows a jaw apparatus consisting of a ventral tongue-like rasp with two sub-dorsal rasps. Otherwise, Zalophora present three cuticularized plates in the anterior part of the oesophagus, with their margins serrated ( Hunt, 1994). The distinctive vulval flap and caudal alae of Trachyglossoides gen. nov. are absent in Zalophora .

Type locality: La Jaula, San José de Las Lajas, Mayabeque province, Cuba.

Type host: Spirobollelus sp. (Diplopoda: Spirobolida: Spirobollelidae).

Site: Hind gut.

Etymology: Species dedicated to the distinguished Cuban naturalist Francisco Jimeno y Fuentes (1825-1891), pioneer of the studies on Natural History in Cuba and founder of the first Cuban collections.

Figures

FIGURE 1: Trachyglossoides jimenoi gen. nov. sp. nov. Female. A. Oesophageal region, lateral view. B. Vulval flap. C. Vulva, lateral view. D. Tail, lateral view. E. Habitus.

FIGURE 2: Trachyglossoides jimenoi gen. nov. sp. nov. Male. A. Tail, lateral view. B. Tail, ventral view. C. Spicule. D. Habitus.

FIGURE 3: Trachyglossoides jimenoi gen. nov. sp. nov. SEM images. Male. A. Cephalic end, dorsolateral view. B. Cephalic end, ventral view. C. Oral aperture. D. Microtricha at level of the cephalic end. E. Microtricha al level of the midbody. F. Tail, ventrolateral view. G. Tail, lateral view. H. Tail tip and spicule. Scale bars: A, G, F = 0.100 mm. B = 0.050 mm. E = 0.020 mm. C, D, H = 0.040 mm.