Texoreddellia chihuahuensis Espinasa, Sprous, Posso, Mitchell, Espinasa and Lin, 2023

Espinasa, Luis, Sprous, Peter, Posso, Kara, Mitchell, Andrew, Espinasa, Monika & Lin, Jonathan, 2023, Miocene divergence for Texoreddellia? An important component of the cave-adapted fauna of Texas and northern Mexico, Zootaxa 5256 (3), pp. 267-278 : 269-274

Texoreddellia chihuahuensis Espinasa, Sprous, Posso, Mitchell, Espinasa and Lin , new species

Figs. 2‒4

Type locality. Holotype female: Zara-3178: México: Chihuahua: Ascensión: Gruta el Sabinal. 30.9329985 o N 107.6483297 o W. 1491 masl. 29-Aug-2008. Paul Bryant Col . Holotype in the Texas Memorial Museum Invertebrate Zoology Collection # 82,740.

Description. Specimen badly deteriorated, most appendages broken ( Fig. 2A, B ). Body length 10.1 mm. General color light yellow to white. Macrochaetae simple or bifid apically. Scales elongate, multiradiate, apically tricuspid with one long median and two shorter lateral projections ( Fig. 3E ). Body scaled but many scales lost since collection. Head apparently with setae only as no distinct scale sockets were visible. Thoracic terga and abdomen with setae and scales. Mouthparts and abdominal stylets with setae only.

Pedicellus in females about one-third length of scape of antennae ( Fig. 2 C-D). Pedicellus in males unknown. Head with approximately 8 + 8 macrochaetae on border of insertion of antenna ( Fig. 2 C-D).

Mouthparts relatively short and robust. Labial palp ( Fig. 3A, B ) with apical article longer than wide and close to equal in length to penultimate article. Penultimate article about 1.5 times longer than wide and with a bulge containing two macrochaetae. Labium and first article of labial palp with macrochaetae. Apex of galea with two conules of similar width. Two teeth on lacinia ( Fig. 3C ). Mandible with multiple macrochaetae.

Abdominal terga and sterna as in other members of genus. Abdominal sterna II‒VII subdivided into coxites and sternites. Median region of sternites with 1 +1 or 2 + 2 sublateral macrochaetae at posterior hind borders and with 1 + 1 macrochaetae near suture at about middle of segment.

Stylets IX broken, but presumably larger than others, with 3 macrochaetae and an extra subapical pair as in other members of Texoreddellia . Stylets II‒VIII with 2 macrochaetae and an extra subapical pair ( Fig. 4A ). Terminal spine with small teeth. Genital area of male unknown. Urotergite X shallowly emarginate.

Subgenital plate of female parabolic, with many setae ( Fig. 4 A-B). Ovipositor tip broken, total length and number of annuli unknown. Portion of gonapophysis present with 8 annuli ( Figs. 4A, B ). Apex of stylets VIII reaching middle of eighth annulus annuli of gonapophysis. Urotergite X with a long and shallow posterior emargination ( Fig. 4C, D ).

Distribution. Known only from type locality ( Fig. 5 ). Gruta el Sabinal is situated at the northern end of the carbonate Cuchillo Group outcrop, with igneous peaks visible just to the north of it. A narrow entrance drops vertically into a series of chambers, with prominent mineralization visible in the reddish bedrock walls. The lower part of the cave has a passage morphology consistent with a vadose speleogenesis, and has speleothems covering the walls. Increased moisture in this section resulted in detection of multiple troglobitic species.

Etymology. The name chihuahuensis (in genitive singular) refers to the region inhabited by the species, in caves in the state of Chihuahua, Mexico.

Figures

FIGURE 2. Texoreddellia chihuahuensis n. sp. Holotype female. A, B) Dorsal and ventral views, respectively. C, D) Head, entire dorsal view and central seta-bearing region, respectively. Body length in A & B = 10.1 mm.

FIGURE 3. Texoreddellia chihuahuensis n. sp. A) Mouth parts. B) Labium. C) Galea and lacinia. D) Maxilla. E) Scales.

FIGURE 4. Texoreddellia chihuahuensis n. sp.A, B) Posterior region.Ovipositor broken after eighth annulus.C, D; Urotergite X.

FIGURE 5. Gruta el Sabinal (type locality). A) Map of Gruta el Sabinal, showing chamber passage morphology in upper section, followed by an abandoned vadose streamway. B) Entrance to Gruta el Sabinal. C) First chamber. D) Lower vadose passage where the specimen of Texoreddellia chihuahuensis n. sp. was found.