Tripylella mexicana, Prado-Vera, Ignacio Cid Del, Ferris, Howard & Nadler, Steven A., 2016

Prado-Vera, Ignacio Cid Del, Ferris, Howard & Nadler, Steven A., 2016, Five new species of the genus Tripylella (Nematoda: Enoplida: Tripylidae), Zootaxa 4109 (2), pp. 198-217 : 200-204

Tripylella mexicana sp. n.

( Fig. 1 A–D, Fig. 2 A–D)

Measurements: See Tables 1 and 2.

Female n=14: Body C-shaped upon relaxation and fixation. Cuticle very thin, 1 Μm, with fine striations and anastomoses. Small setae and pores present around and along the body. Head region rounded, 13–15 (14±0.2) Μm wide. Inner labial papillae conoid; outer labial setae conoid 2–3 (2.7±0.1) Μm long; cephalic setae small, 1 Μm long, and separated from the outer labial setae by <1Μm so that they appear as a single whorl of six longer and four shorter setae. The dorsal tooth is 13–18 Μm (14.8±0.3) from the anterior end of the body and 2–3 (2.2±0.1) Μm behind the small subventral teeth. The dorsal tooth and subventral teeth are in adjacent stomal chambers; the anterior chamber is very small and sometimes appears to be contiguous with the posterior chamber. Amphids caliciform, 8–11 (9.7±0.2) Μm from anterior end of the body. Distance from base of pharynx to vulva is 141–283 (205±10) Μm. Cardia very conspicuous, 20–27 (25±0.6) Μm long and 20–26 (24±0.6) Μm wide, comprised of six cells, the anterior and posterior of medium size and the median cells larger. Excretory pore observed in ten of the 14 specimens.

TABLE.2. Morphometric data for paratypes of Tripylella spp. n. (measurements in Μm ± S.D followed by range, except where indicated).

Female gonads reflexed, the anterior 47–104 (81±5.4) Μm long, 6.2–14.2 (10.9±0.7)% of the body length, and the posterior 19–132 (88±8.6) Μm long, 2.4–16.2 (11.9±1.1)% of the body length (we consider the very short posterior gonad in one specimen to be a developmental anomaly). Vulva without protruding lips but with small oval cuticular structures. Rectum 18–25 (21±0.6) Μm long or 0.7–1.0 (0.8±0.02) times anal body diameter. Tail cylindroid, wide anteriorly for 22–27 (25±0.4) Μm or 42–65 (56 ± 1.86)% of its length and then narrowing abruptly, ending in a spinneret 2–4 (3.1±0.2) Μm long. Two pairs of caudal setae present, one pair at seven annuli posterior to the anus, in a lateral position, and the second pair in a latero-dorsal position, also a single seta in a dorsal position, less than 20 µm from the point at which the tail becomes reduced in diameter.

Male: Unknown.

Type Locality and Habitat: Moss on the trunk of a pirul tree, Schinus molle L., in La Purificación, Tepetitla, Texcoco, México State, México, N19°31'01.7", W98°48'37.7", 2421 m above sea level. Collector I. Cid del Prado- Vera on August 10, 2008.

Type Specimens: Holotype female ( CNHE 9053) and paratypes ( CNHE 9054) in CNHE; paratypes in CNCP and NCE.

Etymology: The specific epithet refers to México, the type locality of the species. Diagnosis and Relationships: Tripylella mexicana sp. n. is characterized by the small size of the body, the finely-striated cuticle that has many anastomoses, pores and small setae along the body, the short pharynx, short tail, and the presence of a readilyvisible excretory pore, the anterior position of the subventral teeth in relation to the small dorsal tooth and the teeth contained in adjacent stomal chambers, the absence of cervical setae, the vulval lips not protruding, and the vulva with small oval sclerotized pieces.

Tripylella mexicana sp. n. is close to T. iucunda Andrássy, 2008 in the lengths of the body, setae, pharynx, and tail. It differs in having a finely-striated cuticle vs. the smooth cuticle of T. iucunda , in having a smaller dorsal tooth, in the presence of an excretory pore and of abundant body pores, in the spherical (20– 27 x 20–26 µm) vs. discoid (17– 20 x 9–12 µm) cardia, and in the small oval vs. larger heart-shaped sclerotized pieces in the vulva. As a caveat, some of the minute surface characters described are only evident by SEM which was not used in the Andrássy (2008) descriptions.

Tripylella mexicana sp. n. is similar to T. intermedia ( Bütschli, 1873) Brzeski & Winiszewska-Ślipińska, 1993 in the shape of the tail, the size of the outer labial and cephalic setae, the short gonads, and the finely-striated cuticle. It differs in the presence of body pores, the distance of the excretory pore from the anterior end, 80–93 (86±1.4) Μm vs. 94–101 Μm, in the length of the body 0.63–0.82 (0.74±0.02) mm vs. 0.81–0.96 mm, in the c ratio, 5.5–7.5 (6.3±0.1) vs. 7.3–8.3, in the relative length of the cylindrical anterior part of the tail 42–65 vs. 60–67% of tail length, and in the absence of setae on the tail of T. intermedia .

Also, T. mexicana is close to T. muscusi in the size of the outer labial and cephalic setae, in the presence of abundant body pores, the position of the vulva, the subventral teeth anterior to the dorsal tooth, and the finelystriated cuticle. It differs in that T. mexicana is a smaller nematode than T. muscusi , with body length 0.63–0.82 (0.74±0.02) mm vs. 0.80–1.02 (0.94±0.02) mm, pharynx length 141–184 (160±3.6) Μm vs. 184–207 (201±1.8) Μm, in the length of the tail, 99–132 (117 ±2.8) vs. 123–160 (140±2.9) Μm, in the distance from vulva to anus 222–292 (256±7.1) vs. 273–380 (339±7.8) Μm, in smaller values of indices a and ć 20.25 (22±0.3) and 4.1–5.1 (4.7±0.08) vs, 24–29 (26±0.4) and 4.9.5.7 (5.3±0.06), respectively, and in the oval shape of sclerotized pieces around the vagina vs. pear shaped pieces in T. muscusi .

Molecular Characteristics: See Molecular Diagnostics section.

Comments: We have examined specimens of a population of Tripylella sp. from Pueblo Nuevo, Hidalgo State, México. Tripylella mexicana sp. n. is very close to that population in the size of the body, size of the pharynx and tail, the position of the vulva, and in that the subventral teeth are usually posterior to the dorsal tooth although in some specimens they appear to be anterior. It differs in the size of the cardia 20–27 vs. 12–21 Μm long and 20–26 vs. 17–24 Μm wide, in the length of the narrower portion of the tail 38–57 vs. 40–70 Μm, and in having a more finely-striated cuticle. We consider the Pueblo Nuevo population to be a variant of T. mexicana sp. n..

Figures

FIGURE 1. Tripylella mexicana sp. n. Female (A. D). A. Entire body; B: Anterior end; C: Pharyngo-intestinal junction; D: Tail. Tripylella muscusi sp. n. Female (E. H) E: Anterior end; F: Pharyngo-intestinal junction; G: Vulva region; H: Tail.

FIGURE 2. Tripylella mexicana sp. n. Female (A. D). A: Cephalic region, dorsal view; B: Annuli with anastomoses, somatic setae and body pores; C: Vulva, latero-ventral view; D: Tail, lateral view.

Tables

TABLE 1. Morphometric data for holotypes of females of Tripylella sp. n. (measurements in Μm ± S. D except where indicated).

Character	T. mexicana sp. n.	T. muscusi sp. n.	T. quitoensis sp. n.	T. fatimaensis sp. n.	T. dentata sp. n.
L a	0.820 mm 22.8	0.994 mm 24.9	0.716 mm 23.9	0.773 mm 22.1	0.839 mm 22.7
b c	4.5 6.2	4.8 6.8	4.0 7.5	4.2 6.9	4.2 7.7
c’	4.9	5.7	4.6	4.4	4.4
V% Vulva to anus	48.6 287.5	48.3 367.6	52.6 240	49.9 273	51.7 292
Dorsal tooth from anterior end	15	16	13	13	17
Pharynx length Excretory pore	184 88	207.4 -	179 absent	183.7 86	197.9 absent
Tail	132	146.1	96	111	109.5
Tail% body	16.1	14.7	13.4	14.3	13.1