Ixchela Huber 2000
Creators: name: Valdez-Mondragón, Alejandro
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Ixchela

description: Ixchela Huber, 2000
Type species: Ixchela furcula (F. O. Pickard-Cambridge, 1902), originally described in Coryssocnemis Simon, 1893; by original designation (Huber, 2000). Type locality: 1 female holotype from Tecpam in the Región de los Altos (Cerro Tecpam, Departmento Chimaltenango), Guatemala, around 2300 m, Coll. Otto Stoll. Godman & Salvin Coll., in BMNH (F. O. Pickard-Cambridge, 1902; Huber, 1998).
Included taxa: Ixchela simoni (O. Pickard-Cambridge, 1898), Ixchela abernathyi (Gertsch, 1971), Ixchela furcula (F. O. Pickard-Cambridge, 1902), Ixchela pecki (Gertsch, 1971), Ixchela placida (Gertsch, 1971), Ixchela mixe new species, Ixchela huberi new species, Ixchela juarezi new species, Ixchela grix new species, Ixchela taxco new species, Ixchela franckei new species, Ixchela tzotzil new species, Ixchela santibanezi new species, Ixchela huasteca new species, and Ixchela viquezi new species.
Diagnosis: Distinguished by the prolateroventral apophysis of the palp bulb of the male (PAB) (Figs 26, 38, 66); by the apical-dorsal spine-shaped projection on the embolus (arrow Fig. 25; 53, 65); by the apical-vental projection on the embolus (arrow Fig. 26; 37, 53); by the curved spine distally on procursus (Figs 25, 37, 53); by the ventral protuberance with long setae on the procursus (VPP) (Figs 25, 37, 65); by the conical, straight and long procursus, wide basally (Figs 25, 37, 53); by the sclerotized small and sub-distal spine on the embolus (arrows Figs 38, 55, 80); and by the frontal apophysis of chelicerae on males (FAC) (Figs 22, 35, 75).
Description: Total length ~ 4.5–10 mm (prosoma+opisthosoma). Sexual dimorphism slight. Carapace with coloration pale yellow, light orange, beige or pale brown. Carapace with marginal brown or gray spots on some species (Figs. 32, 61, 73), absent or inconspicuous in others (Figs. 20, 48, 87). Clypeus brown, yellow or orange, with a wide, darker longitudinal region on some species (Figs. 51, 64) or without it in other species (Figs. 23, 33). Male clypeus unmodified (Figs 23, 33, 51). Ocular region moderately elevated, with eight eyes (Figs 19, 20, 23). Ocular region dark brown or dark orange, darkened posteriorly, near the fovea (Figs 32, 48, 61). Fovea of the carapace with irregular brown or gray region around (Figs 32, 48, 61); this region wide in some species (e.g. I. furcula, I. simoni) (Figs 32, 73), or thin in others (e.g. I. pecki, I. mixe) (Figs 48, 87). Female chelicerae unmodified. Male chelicerae with SAC on some species (e.g. I. abernathyi, I. placida) (Figs 21, 74), vestigial (e.g. I. simoni, I. tzotzil) (Figs 74, 162); or absent (e.g. I. furcula, I. huberi) (Figs 34, 100). Some species with SAC distally on FAC (e.g. I. pecki, I. mixe) (Figs 49, 88). Sternum wide, fused to the labium. Endites larger than wide, with retrolateral apophysis on males, absent on females. Labium and endites pale distally. Male palp with femur conical, wider distally than basally, with VAF (Figs 25, 37, 53), except I. mixe (Fig. 91). Male palp with tibia wide, wider distally than basally (Figs. 37, 53, 65). Palp tarsus dorsally with two distal apophyses (arrows Fig. 36). Tarsal organ exposed (e.g. I. furcula) (Huber 2000). Bulb rounded and wide (Figs 24, 26, 52, 54). Embolus conical and wide (Figs 25, 26, 65, 66). Embolus with two darker, longitudinal sclerotized lines, one dorsal (arrow Fig. 52, left arrow Fig. 53), and another ventral (right arrow Fig. 53); the ventral one projected from PAB (Figs 25, 37, 53). Legs long and robust, tibia I (length/diameter) (l/d) about 20–60; leg formula 1423 in most of the species, in some species 1243. Legs yellow, orange, reddish or brownish, darker on femora. Femora, tibiae and metatarsi with eight longitudinal rows of oblique setae, evenly spaced around the circumference. Legs with few small vertical setae along and around, without spines or curved setae. Three trichobothria on tibiae I, proximal, with the retrolateral trichobothria the most distal. Legs with numerous dark rings on femora and tibiae in some species (e.g. I. abernathyi, I. tzotzil) (Figs 1, 12) and in others without numerous rings, but with at least one basal ring and one sub-distal ring on femora and tibiae (e.g. I. simoni, I. huberi) (Figs 4, 6). Opisthosoma pale or dark blue, gray or pale green, with small white spots; globular in some species (e.g. I. furcula, I. pecki) (Figs 31, 47), and conical in others (e.g. I. abernathyi, I. simoni) (Figs 19, 72). Opisthosoma larger than high, except in I. mixe where it is higher than long (Fig. 86). Male gonopore without epiandrous spigots (e. g. I. furcula) (Huber 2000); gonopore plate oval, square or trapezoidal. Epigynum with different shapes, with paired or unpaired apophysis, long or small apophyses, wider than large or larger than wide (Figs 28, 39, 56, 69, 95). Epigynum internally with wide, paired PP, with MSE between PP (Figs 29, 40, 57); most of the species with sac-shaped concavities between MSE and PP (arrows Figs 57, 70), except I. franckei, I. santibanezi and I. viquezi (Figs 156, 184, 212). Epigynum in some species with one small rounded pit (e.g. I. taxco, I. franckei) (arrows Figs 142, 159).
Distribution: The genus Ixchela Huber, 2000 is widely distributed from Northeastern Mexico to Nicaragua. Although in this work I have not seen specimens from Nicaragua, Huber (2000) examined one male of an undescribed species from Nicaragua, Matagalpa, Fuente Pura, deposited in Museo Entomológico Nicaraguense, León, Nicaragua.
Natural History: The genus Ixchela has a natural distribution in temperate climate zones, principally in pine, oak or pine-oak forest, between 1000–2950 m of elevation (Figs 13–15, 17, 18; Appendix 1), although some species like Ixchela santibanezi new species was collected in tropical rain forest at 1190 m (Fig. 16), and I. juarezi new species was collected in a thorny scrub forest at 1900–2180 m. Although there has been a intensive collecting at low elevations, it seems that the genus Ixchela only occurs above 1000 m of elevation, while below this elevation only other genera such as Physocyclus Simon, 1893 and Psilochorus Simon, 1893 have been collected, principally in deciduous tropical forest. Bernhard A. Huber (per. comm.) said that the high altitude of the genus Priscula Simon, 1893 in South America seems to be a relict genus. Similarity, this could be the case for Ixchela, where again its high elevation distribution possibly reflects its relictual status.
The spiders sampled during new fieldwork were found among fallen logs, boulders on the ground, under dry leaves of agave plants and frequently on their irregular sheet webs on embankments along road-cuts, specifically in shaded, moist areas covered with roots and leaf-litter (Figs 15, 17, 18). In karstic zones, the spiders are found in their sheet webs frequently inside the caves (Fig. 14); on walls, holes in walls, among boulders on the floor, or among karst formations (stalagmites and columns) (Figs 1–3, 5, 9). Although some species have been collected frequently inside caves with relatively high densities, all species can be considered troglophiles and not strict troglobites or with conspicuous troglomorphic modifications (Figs 1–12).
description: Published as part of Valdez-Mondragón, Alejandro, 2013, Taxonomic revision of the spider genus Ixchela Huber, 2000 (Araneae: Pholcidae), with description of ten new species from Mexico and Central America, pp. 285-327 in Zootaxa 3608 (5) on pages 288-289, DOI: 10.11646/zootaxa.3608.5.1, http://zenodo.org/record/216512