Psilochorus pallidulus Gertsch 1935
Creators: name: Slowik, Jozef
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Psilochorus
Psilochorus pallidulus

description: Psilochorus pallidulus Gertsch, 1935
Figs. 99–107, 190
Psilochorus coahuilanus Gertsch & Davis, 1937. New synonymy.
Types. P. pallidulus: ɗ holotype, from Edinburg (26.301 N, 98.16 W), Hidalgo County, Texas USA; coll: S Mulaik, Sep–Dec-1933, AMNH. Not examined.
P. coahuilanus: Ψ holotype, Ψ paratypes from 20 miles east of San Pedro, Coahuila, Mexico; coll: A M & L I Davis, 5-Jul-1936, AMNH. Not examined.
Specimens examined. 7 ɗ, 12 Ψ; USA, Texas, Brewster County, 3 ɗ, 2 Ψ, Chisos Mtns, Big Bend N P, Karl W Haller, 14-Dec-1954, AMNH; 1 ɗ, 5 Ψ, Big Bend N P, The Basin, Chiso Mtns, W J Gertsch, 28-Sep- 1950, AMNH; 1 ɗ, 1 Ψ, Hot Springs, D & S Mulaik, 27 May – 8 June 1996, AMNH; 1 Ψ, Persimmon Gap, Big Bend N P, L Vincent, C E Griswold, 28-Jun-1975, EM; 2 ɗ, 3 Ψ, Big Bend N P, Castolon and vic., Gertsch, Hastings, 24-Aug-1967, AMNH.
Diagnosis. Specimens may be distinguished by: male spur almost straight and sharply pointed in dorsal view (Fig. 99), spur turns sharply down about mid-length in lateral view (Fig. 100), spur is also rather long with its’ total length being close to the length of the chelicerae; bulbous, longer than wide, posteriorly directed protuberances on the MEP which overhang the PEP (Fig. 105).
Male: (N=2) Total length: 2.30, 2.07; carapace length: 0.89, 0.92; carapace width: 0.84, 0.88; leg 1: 17.04, 17.98 (4.81, 4.92 + 0.32, 0.35 + 5.03, 5.31 + 5.88, 6.11 + 1.02, 1.29); tibia 2: 3.33, 3.57; tibia 3 missing; tibia 4: 3.45, 3.73. 18–22 leg I tarsal segments; femur1/carapace length: 5.40, 5.34; RT at 9.7%, 9.0%; DT at 6.1, 6.7%. Color typical for genus, although the longitudinal dark line on the carapace may appear faint. Spur long, straight, ending in fine point (Fig. 99), originating from proximal portion of chelicerae (Fig. 100). Procursus linear, distal area only slightly swollen, end curving ventrally, truncate (Fig. 103). Bulb apophysis appears bifurcate with the prolateral tip connected to a prolateral tab, other tip centered, pointed (Figs. 101, 102).
Female: (N=5) Total length: 2.52 ± 0.32; carapace length: 0.96 ± 0.10; carapace width: 0.90± 0.08; leg 1: 13.78 ± 0.66 (3.85 ± 0.22 + 0.32 ± 0.04 + 4.07 ± 0.19 + 4.40 ± 0.20 + 1.14 ± 0.09); tibia 2: 2.73 ± 0.19; tibia 3: 2.14± 0.11; tibia 4: 2.94 ± 0.16. 19–22 leg I tarsal segments; femur1/carapace length: 4.01 ± 0.26; RT at 7.9–11.2%; DT at 6.3–8.3%. Color same as male. No AEP, MEP large, with two long cylindrical protuberances located on each lateral side (Fig. 105), overhanging the PEP (Fig. 107). PEP low rounded, with small PEP projection (Fig. 106).
Synonymy remarks. Males of P. pallidulus were described by Gertsch (1935) and females of P. coahuilanus were described by Gertsch & Davis (1937) without knowing the other sex. However specimens examined which were collected by Gertsch, by Davis, and others from the type localities include males of P. pallidulus and females of P. coahuilanus together indicating that the two are a pair. It is interesting to note that in Gertsch & Davis 1942 a note is made that a female P. pallidulus being collected, however the Texas specimens used in Gertsch and Mulaik 1940 were examined and are clearly a male P. pallidulus with a female P. coahuilanus, labeled as the later.
Remarks. This species is easily separated by the spur shape and MEP of the epigynum.
Distribution. Southern Texas into Mexico.
description: Published as part of Slowik, Jozef, 2009, A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae), pp. 1-53 in Zootaxa 2144 on page 31, DOI: 10.5281/zenodo.188626