Psilochorus coloradensis, Slowik, Jozef, 2009

Slowik, Jozef, 2009, A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae), Zootaxa 2144, pp. 1-53 : 16

Psilochorus coloradensis new species

Figs. 1, 47–55, 189

Types. ɗ holotype and three Ψ paratypes from Claystone Caves (39.52 N, 107.92 W), Garfield County, Colorado USA; coll: J Slowik & P E Cushing, 23-Jul-2006, DMNS.

Further paratypes. 2 ɗ, 6 Ψ; USA, Colorado, Garfield County, 1 ɗ, 3 Ψ, Claystone Caves, 23-Jul-2006, DMNS; 2 Ψ, Claystone Caves, 20-Oct-1999, DMNS; Moffat County, 1 ɗ, 1 Ψ, Whispering Cave, Dinosaur N M, 12-Aug-2006, DMNS.

Etymology. The specific epithet refers to the state of the type locality.

Diagnosis. Specimens may be distinguished by: a bi-lobed procursus tip (Fig. 51) in conjunction with a short wide cheliceral spur (Fig. 47), the presence of an AEP (Fig. 52), an un-ridged MEP (Fig. 54) and notches present along the lateral edge of the MEP (Figs. 53, 55).

Male: (Holotype) (Figs. 47–49, 51) Total length: 2.63; carapace length: 0.94; carapace width: 1.04; leg 1: 20.86 (6.26 + 0.37 + 5.81+ 6.86 + 1.56); tibia 2: 3.58; tibia 3: 3.30; tibia 4: 3.75. 23 leg I tarsal segments; femur1/carapace length: 6.66; RT at 12.6%; DT at 7.6%. Color typical for the genus. Spur short, triangular in dorsal view (Fig. 47), located on the proximal half of the chelicera (Fig. 48). Procursus short with a bi-lobed distal area, with one lobe located on the dorsal edge and the other at the apex (Fig. 51). The bulb apophysis is located on the prolateral side with a bifurcate end (Figs. 49, 50), both tips pointed. Retrolateral tab extending across bulb from bulb apophysis to retrolateal side.

Female: (N=3) Total length: 2.51 ± 0.20; carapace length: 0.84 ± 0.24; carapace width: 0.93± 0.17; leg 1: 17.1 ± 0.17 (4.83 ± 0.03 + 0.33 ± 0.04 + 5.05 ± 0.03 + 5.60 ± 0.06 + 1.30 ± 0.07); tibia 2: 3.57 ± 0.02; tibia 3: 2.89± 0.01; tibia 4: 3.33 ± 0.10. 22 leg I tarsal segments; femur1/carapace length: 4.93 ± 0.17; RT at 13.2–13.3%; DT at 7.3–8.3%. Color typical for genus. AEP small rounded (Fig. 55). MEP smooth, rounded, notches located on lateral edges when viewed ventrally (Figs. 53, 55). PEP low, oblong, exposing MEP in dorsal view (Fig. 54)

Remarks. Males of this species share spur shape with P. topanga ; however, the procursus tip will separate the two. Females most closely resemble P. acanthus in which it differs in the presence of pronounced notches on the lateral edge of the MEP. This species has only been found from two caves on the Western slope of the Rocky Mountains in Colorado. It appears to be exclusively cave dwelling as P. imitatus has been collected in proximity of the caves entrances but not from the caves and no P. coloradensis have been collected outside of the caves. The eyes of this species appear normal and it shows no other signs of troglomorphism.

Distribution. Caves in North-Western Colorado.