Hoplobunus: Goodnight & Goodnight 1971: 40 (in part). Troglostygnopsis: Šilhavý, 1974: 185 (in part).

Distribution: Only known from caves in Municipio de Gómez Farías, Tamaulipas, Mexico.

Type species: Hoplobunus inops Goodnight & Goodnight, 1971.

Included species: Monotypic.

Etymology: Generic name derived from the nahuatl word Mictlán, that means underworld in Aztec mythology, referring to the troglobitic habits of the only known species of this genus. It is feminine in gender.

Diagnosis: Scutum rectangular (Fig. 54D). Ocularium on the anterior margin of prosoma, elevated, blunt and smooth, without eyes (Fig. 54B). Clear lateral areas projected in digitiform tubercles, clear area on apex of dorsal area V forming a large, rounded tubercle (Fig. 54A, D). Basichelicera elongated. Lacking ornamentation on the dorsum and legs. Femur IV noticeably longer than scutum. Male genitalia: pars distalis slightly swollen in the middle, ventral plate a little compressed in lateral view, apical margin convex. Four pairs of lateral setae, cylindrical and shorter than width of pars distalis. Four pairs of ventral microsetae along lateral margins of pars distalis, basal pair separated from the rest. Two pairs of parastylar setae, lateral projection of follis lobate, rounded distally (Fig. 55).

MICTLANA INOPS (GOODNIGHT & GOODNIGHT, 1971) COMB. NOV.

(FIGS 54, 55, 57, 64I)

Hoplobunus inops Goodnight & Goodnight, 1971: 40, fig. 17.

Troglostygnopsis inops: Šilhavý, 1974: 185, fig. 21 (generic transfer, by implication).

Type locality: MEXICO: Tamaulipas: Gómez Farías, Cueva de La Capilla 13.5 km NW of Gómez Farías.

Material examined: MEXICO: Tamaulipas: ♂ male [CNAN (22.xi.2005; S. Summers and C. Savvas)] (23°3′56.98″N, 99°9′45.50″W). Municipio Gómez Farías, Sótano del Plan. 1 juvenile [CNAN (22.xi.2005; S. Summers)] (23°3′49.08″N, 99°9′49.78″W). Municipio Gómez Farías, Resumidero de Jineo.

Other material: MEXICO: Tamaulipas: ♂ holotype [AMNH (25.xi.1966; O. Knox and E. Alexander)], Sótano de la Joya de Salas, 21 km NW of Gómez Farías, not examined. 2 ♀ paratypes [AMNH (17.viii.1968; R. W. Mitchell)], Cueva de la Mina, 7 km NW of Gómez Farías, not examined. 1 ♂, 1 ♀ and 5 juveniles [MCZR (23,25. xi.1969; R. Argano and V. Sbordoni)], Sierra de Guatemala, Gómez Farías, 2160 m, Cueva de la Perra (material examined by Šilhavý, 1974), not examined. Additionally, Goodnight & Goodnight (1973) mentioned several records in Tamaulipas for this species but did not specify the number or sexes of the specimens; not examined.

Diagnosis: See generic diagnosis.

Redescription: Male: Measurements: scutum length 2.6, maximum scutum width 1.8. Legs. I 4.75/0.85/3.47/ 5.10, II 4.22/1.40/?.??/?.??, III 3.00/0.57/2.00/3.20, IV 4.45/ 1.25/?.??/?.??. Dorsum. Scutum rectangular, prosoma slightly narrower than rest of scutum (Fig. 54D). Dorsum smooth, with only a few, very small setae on the middle of mesotergal areas. Mesotergal sulci not visible. Ocularium at the anterior margin of prosoma, base elliptical, conic, and distally blunt, apex pointed frontally, eyes absent (Fig. 54B, D). Lateral clear areas projected from the scutum in a digitiform shape, thin, pointing backwards (Fig. 54A). Lateral clear areas on apices of dorsal area V projected in rounded tubercles (Fig. 54D). Projections on free tergites absent. Free tergites with a median row of small tubercles; apical setae present, long. Venter. Coxae I– III with a median row of spiniform tubercles, noticeably elongated. Coxa IV with scattered tubercles, rounded, without distal setae. Stigmatic area not elongated. Free sternites with a median row of small tubercles, similar to free tergites. Anal plate smooth. Chelicera. Basichelicera slightly elongated. Cheliceral hand round, small. Fixed finger with five blunt teeth, the middle slightly elevated; movable finger with basal triangular tooth, apically rounded. Pedipalps. Patella with two mesal spiniform tubercles. All spiniform tubercles of pedipalps very long (Fig. 54C). Legs. All legs similar in thickness, ornate with only few setae. Metatarsus II without annuli. Tarsal count 15(7):33/34(13):7:9. Male genitalia. Pars distalis lancet-shaped, slightly swollen in the middle, ventral plate slightly flattened in lateral view. Lateral setae cylindrical, shorter than width of pars distalis, without sulcus. Two pairs of laterobasal parastylar setae. Four pairs of ventral microsetae along lateral margins of pars distalis, basal pair slightly displaced from the rest, the two middle pairs close to each other. Lateral projection of follis robust, lobate, and distally pointed. Spiniform projections not exposed but visible (Fig. 55). Female. No specimens were examined. Šilhavý (1974) recorded two females from different caves, but he did not describe them.

Taxonomic accounts: Originally, Goodnight & Goodnight (1971) assigned this species to the genus Hoplobunus Banks, 1900, and later Šilhavý (1974) transferred it to the genus Troglostygnopsis. We examined the type species of the genus Hoplobunus and according to the results of our cladistic analyses, this species is a completely different taxon inside the family Stygnopsidae, unrelated to Troglostygnopsis anophthalma Šilhavý, 1974; therefore, it is described in this work as a new genus.

Goodnight & Goodnight (1973) recorded Hoplobunus inops from ‘Cueva del Río San Antonio, 10 Km SSW Acatlán, Oaxaca’. Subsequently, Reddell (1981: 166) mentioned that this record ‘is doubtless in error’, because the cave region of the type locality and this particular record are miles apart and unconnected underground. Finally, Kury (2003: 240), based on personal communication with J. Cokendolpher, indicated that the record was false. We examined an adult male from a cave near to Cueva del Río San Antonio, and based on the male genitalia, this troglomorphic species from Oaxaca does not correspond with either Mictlana from Tamaulipas or Troglostygnopsis from Chiapas, and will be described in a future contribution.