Ixchela Huber, 2000

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, Zootaxa 3608 (5), pp. 285-327 : 288-289

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 ).

Figures

FIGURES 19 – 30. Ixchela abernathyi (Gertsch, 1971). Male: 19, Habitus, lateral view. 20, Carapace, dorsal view. 21, Chelicerae, frontal view. 22, Chelicerae, lateral view. 23, Carapace, frontal view. 24, Bulb and procursus, dorsal view. 25 – 26, Left palp, retrolateral and prolateral views respectively (arrows indicate the apical-dorsal projection spine-shaped on the embolus, and the apical-vental projection respectively). Female: 27, Epigynum, frontal view. 28, Epigynum, ventral view. 29, Epigynum, dorsal view. 30, Epigynum, left lateral view. Scales: 1 mm (Figs 19, 21, 23, 25, 26), 0.5 mm (Figs 20, 22, 24, 27 – 30).

FIGURES 31 – 46. Ixchela furcula (F. O. Pickard-Cambridge, 1902). Male: 31, Habitus, lateral view. 32, Carapace, dorsal view. 33, Carapace, frontal view. 34, Chelicerae, frontal view. 35, Chelicera, lateral view. 36, Bulb and procursus, dorsal view (arrows indicate the two basal apophyses on dorsal part of procursus). 37 – 38, Left palp, retrolateral and prolateral views respectively (arrow indicates the sclerotized spine small and sub-distal on the embolus). Females: San Vicente de Picaya: 39 – 40, Epigynum, ventral and dorsal view respectively. 43, 45, Epigynum, frontal and lateral view respectively. Parque Nacional La Tigra: 41 – 42, Epigynum, ventral and dorsal view respectively. 44, 46, Epigynum, frontal and lateral view respectively. Scales: 1 mm (Figs 31 – 34, 37 – 42), 0.5 mm (Figs 35, 36, 43 – 46).

FIGURES 60 – 71. Ixchela placida (Gertsch, 1971). Male: 60, Habitus, lateral view. 61, Carapace, dorsal view. 62, Chelicerae, frontal view. 63, Chelicera, lateral view. 64, Carapace, frontal view. 65 – 66, Left palp, retrolateral and prolateral views respectively. 67, Bulb and procursus, dorsal view. Female: 68, Epigynum, frontal view. 69, Epigynum, ventral view. 70, Epigynum, dorsal view (arrow indicates the sac-shaped concavities between MSE and PP). 71, Epigynum, left lateral view. Scales: 1 mm (Figs 60, 61, 64, 65, 66, 68 – 71), 0.5 mm (Figs 62, 63, 67).

FIGURES 47 – 59. Ixchela pecki (Gertsch, 1971). Male: 47, Habitus, lateral view. 48, Carapace, dorsal view. 49, Chelicerae, frontal view. 50, Chelicera, lateral view. 51, Carapace, frontal view. 52, Bulb and procursus, dorsal view (arrow indicates the dorsal sclerotized line on embolus). 53 – 54, Left palp, retrolateral and prolateral views respectively (arrows in Fig. 53 indicate the dorsal sclerotized line (left arrow), and ventral sclerotized line on embolus (right arrow )). 55, Left embolus, prolateraldorsal view (arrow indicates the sclerotized spine small and sub-distal on the embolus). Female: 56, Epigynum, ventral view. 57, Epigynum, dorsal view (arrow indicates the sac-shaped concavities between MSE and PP). 58, Epigynum, frontal view. 59, Epigynum, left lateral view. Scales: 1 mm (Figs 47, 48, 51, 53, 54), 0.5 mm (Figs 49, 50, 52, 55 – 59).

FIGURES 72 – 84. Ixchela simoni (O. Pickard-Cambridge, 1898). Male: 72, Habitus, lateral view. 73, Carapace, dorsal view. 74, Chelicerae, frontal view. 75, Chelicera, lateral view. 76, Carapace, frontal view. 77, Bulb and procursus, dorsal view. 78 – 79, Left palp, retrolateral and prolateral views respectively. 80, Embolus, dorso-distal view (arrow indicates the sclerotized spine small and sub-distal on the embolus). Female: 81, Epigynum, frontal view. 82, Epigynum, ventral view. 83, Epigynum, dorsal view. 84, Epigynum, left lateral view. Scales: 1 mm (Figs 72 – 74, 76, 78, 79, 81 – 84), 0.5 mm (Figs 75, 77, 80).

FIGURES 86 – 97. Ixchela mixe new species. Male: 86, Habitus, lateral view. 87, Carapace, dorsal view. 88, Chelicerae, frontal view. 89, Chelicera, lateral view. 90, Carapace, frontal view. 91 – 92, Left palp, retrolateral and prolateral views respectively (arrows indicate the distal sclerotized spine on the embolus, small and flat distally). 93, Bulb and procursus, dorsal view. Female: 94, Epigynum, frontal view. 95, Epigynum, ventral view. 96, Epigynum, dorsal view. 97, Epigynum, left lateral view. Scales: 1 mm (86, 87, 90 – 92), 0.5 mm (88, 89, 93, 94 – 97).

FIGURES 160 – 172. Ixchela tzotzil new species. Male: 160, Habitus, lateral view. 161, Carapace, dorsal view. 162, Chelicerae, frontal view. 163, Chelicera, lateral view. 164, Carapace, frontal view. 165, Bulb and procursus, dorsal view. 166, Embolus, prolaterodorsal view (arrow indicates the bifurcated spine). 167 – 168, Left palp, retrolateral and prolateral views respectively. Female: 169, Epigynum, frontal view. 170, Epigynum, ventral view. 171, Epigynum, dorsal view. 172, Epigynum, left lateral view. Scales: 1 mm (Figs 160, 161, 164, 167, 168, 172), 0.5 mm (Figs 162, 163, 165, 169 – 171), 0.25 mm (Fig. 166).

FIGURES 98 – 109. Ixchela huberi new species. Male: 98, Habitus, lateral view. 99, Carapace, dorsal view. 100, Chelicerae, frontal view. 101, Chelicera, lateral view. 102, Carapace, frontal view. 103 – 104, Left palp, retrolateral and prolateral views respectively. 105, Bulb and procursus, dorsal view. Female: 106, Epigynum, frontal view. 107, Epigynum, ventral view. 108, Epigynum, dorsal view. 109, Epigynum, left lateral view. Scales: 1 mm (Figs 98, 99, 102 – 104), 0.5 mm (Figs 100, 101, 105 – 109).

FIGURES 1 – 12. Living specimens of the genus Ixchela Huber, 2000, from Mexico. 1, Ixchela abernathyi (Gertsch, 1971), female from Km 227 Carretera Federal No. 70 Cd. San Luis Potosí-Rio Verde, San Luis Potosí. 2, Ixchela placida (Gertsch, 1971), female from Cueva de Atlahuilapa, Veracruz. 3, Ixchela pecki (Gertsch, 1971), female from Cueva de Teopisca, Chiapas. 4, Ixchela simoni (O. Pickard-Cambridge, 1898) from 2 km W of crossroad Omiltemi-Chautipan, Guerrero. 5, Ixchela mixe new species, female with egg sac from cave near Tlahuitoltepec, Oaxaca. 6, Ixchela huberi new species, male from Santa Inés del Monte, Oaxaca. 7, Ixchela juarezi new species, female with egg sac from 2 km E of Guelatao, Oaxaca. 8, Ixchela taxco new species, female from Rancho La Soñadora, 6 km W of Taxco, Guerrero. 9, Ixchela franckei new species, male from Cueva del Borrego, 3.5 km E of Omiltemi, Guerrero. 10 – 11, Ixchela huasteca new species: 10, male from 1.5 km road to Microondas La Pingüica, Querétaro; 11, female with egg sac from Buenavista, near Ahuacatlan, San Luis Potosí. 12, Ixchela tzotzil new species, male from Grutas de Arcotete, Chiapas.

FIGURES 147 – 159. Ixchela franckei new species. Male: 147, Habitus, lateral view. 148, Carapace, dorsal view. 149, Chelicerae, frontal view. 150, Chelicera, lateral view. 151, Carapace, frontal view. 152 – 153, Left palp, retrolateral and prolateral views respectively. 154, Bulb and embolus, prolateral view (arrow indicates the round tip near to PAB). 157, Bulb and procursus, dorsal view. Female: 155, Epigynum, ventral view. 156, Epigynum, dorsal view. 158, Epigynum, left lateral view. 159, Epigynum, frontal view (arrow indicates the small rounded pit). Scales: 1 mm (Figs 147, 148, 151 – 153, 157), 0.5 mm (Figs 149, 150, 154 – 156, 158, 159).

FIGURES 173 – 185. Ixchela santibanezi new species. Male: 173, Habitus, lateral view. 174, Carapace, dorsal view. 175, Chelicerae, frontal view. 176, Chelicera, lateral view. 177, Carapace, frontal view. 178, Embolus, apical view (arrow indicates the concavity between basal protuberance and the PAB). 179, Bulb and procursus, dorsal view. 180 – 181, Left palp, retrolateral and prolateral views respectively. Female: 182, Epigynum, frontal view. 183, Epigynum, ventral view. 184, Epigynum, dorsal view. 185, Epigynum, left lateral view (arrow indicates posterior concavity). Scales: 1 mm (Figs 173, 174, 177, 180, 181, 183, 184), 0.5 mm (Figs 175, 176, 178, 179, 182, 185).

FIGURES 202 – 213. Ixchela viquezi new species. Male: 202, Habitus, lateral view. 203, Carapace, dorsal view. 204, Chelicerae, frontal view. 205, Chelicera, lateral view. 206, Carapace, frontal view. 207 – 208, Left palp, retrolateral and prolateral views respectively. 209, Bulb and procursus, dorsal view. Female: 210, Epigynum, frontal view. 211, Epigynum, ventral view. 212, Epigynum, dorsal view. 213, Epigynum, left lateral view. Scales: 1 mm (Figs 202, 206 – 208), 0.5 mm (Figs 203 – 205, 209 – 213).

FIGURES 134 – 145. Ixchela taxco new species. Male: 134, Habitus, lateral view. 135, Carapace, dorsal view. 136, Chelicerae, frontal view. 137, Chelicera, lateral view. 138, Carapace, frontal view. 139, Bulb and procursus, dorsal view. 140 – 141, Left palp, retrolateral and prolateral views respectively (arrow indicates the vetral protuberance on palp femur). Female: 142, Epigynum, frontal view (arrow indicates the small rounded pit). 143, Epigynum, ventral view. 144, Epigynum, dorsal view. 145, Epigynum, left lateral view. Scales: 1 mm (Figs 134 – 136, 138, 140 – 142), 0.5 mm (Figs 137, 139, 143 – 145).

FIGURES 13 – 18. Typical habitats of spiders of the genus Ixchela Huber, 2000 from Mexico. 13, Oak-pine forest, from Km 227 Federal Highway # 70 Cd. San Luis Potosí-Río Verde, San Luis Potosí: Ixchela abernathyi (Gertsch, 1970). 14, Karstic zone in oak-pine forest, Cueva del Borrego 3.5 km al E of Omiltemi, Guerrero: Ixchela franckei new species. 15, Oak-pine forest from Grutas de Arcotete, Chiapas: Ixchela tzotzil new species. 16, Tropical rain forest outside of Cueva de las Abejas, Chiapas: Ixchela santibanezi new species. 17, Oak-pine forest 3 km E of turn-off to Santa Inés del Monte, Oaxaca: Ixchela huberi new species. 18, Oak-pine forest at “ Rancho La Soñadora ”, 6 km W of Taxco, Guerrero: Ixchela taxco new species. Red arrows indicate the specific locations or microhabitats where specimens of Ixchela can be collected in the field.