Chisosa diluta ( Gertsch & Mulaik, 1940 )

Huber, Bernhard A., Meng, Guanliang & Valdez-Mondragón, Alejandro, 2024, Notes on Chisosa (Araneae, Pholcidae), with the description of a new species from Mexico, Zootaxa 5419 (2), pp. 217-244 : 222

Chisosa diluta ( Gertsch & Mulaik, 1940)

Figs 4A, B , 5–10

Pholcophora diluta Gertsch & Mulaik, 1940: 320 , figs 27–28 (♀).

Pholcophora diluta – Gertsch 1982: 100, figs 19–21, 28–30 (♂ ♀).

Chisosa diluta – Huber 2000: 125, figs 151, 478–489. Eberle et al. 2018 (molecular data). Huber et al. 2018: fig. 2.

Figures

FIGURE 4. Chisosa Huber, 2000; live specimens. A, B. C. diluta (Gertsch & Mulaik, 1940), male from U.S.A., Texas, Big Bend N.P., Tuff Canyon. C, D. C. caquetio Huber, 2019; male and female with egg-sac from Curaçao, Kueba di Brua. E, F. C. caquetio; male from Venezuela, Falcón, Cueva del Guano; female from Venezuela, La Guaira, Catia la Mar.

FIGURE 5. Chisosa diluta (Gertsch & Mulaik, 1940); male and female from Big Bend N.P., Tuff Canyon; ZFMK USA6 (male) and ZFMK USA18 (female). A. Female prosoma, frontal dorsal view. B. Female ocular area, frontal dorsal view. C. Male gonopore. D. Epigynum; arrows point at pockets. E. Male anterior lateral spinneret. F. Female anterior lateral spinneret (ALS) and posterior median spinneret (PMS). Scale lines: 100 µm (A, B, D); 10 µm (C, E, F).

FIGURE 6. Chisosa diluta (Gertsch & Mulaik, 1940); male from Big Bend N.P., Tuff Canyon; ZFMK Kra60. A, B. Male chelicerae, frontal and oblique lateral views. C. Stridulatory pick on male palpal femur. D. Male palpal tarsal organ. E. Left tarsus and procursus, retrolateral view. F. Right bulbal process with sperm duct opening (arrow). Abbreviations: b, genital bulb; pr, procursus; ta, tarsus. Scale lines: 100 µm (A, B, E), 10 µm (C, D, F).

FIGURE 7. Chisosa diluta (Gertsch & Mulaik, 1940); male and female from Big Bend N.P., Tuff Canyon; ZFMK Kra60 (male) and ZFMK USA18 (female). A. Stridulatory file on left male chelicera. B. Female left metatarsus 4, retrolateral view; arrow: putative chemoreceptor; asterisk: ‘cuticular plate’ of unknown function. C, D. Sexually dimorphic ‘vertical’ hairs (arrows) on male tibia 1 (prolateral and retrolateral views). E, F. Tarsal claws on female right tarsus 1 (prolateral view) and female left tarsus 4 (retrolateral view); arrows: putative chemoreceptors. Scale lines: 10 µm.

FIGURE 8. Chisosa diluta (Gertsch & Mulaik, 1940); male and female from Big Bend N.P., Tuff Canyon; ZFMK Kra60 (male) and ZFMK USA18 (female). A. Prolateral trichobothrium on right female tibia 2. B. Retrolateral trichobothrium on left male tibia 2. C. Cuticular plate (arrow) on male left metatarsus 3. D, E. Slender metatarsal hairs (arrows) on female left metatarsus 4 and on female right metatarsus 3. F. Distinctively widened tip of slender metatarsal hair on female left metatarsus 3. Scale lines: 10 µm (A–E); 1 µm (F).

FIGURE 9. Chisosa diluta (Gertsch & Mulaik, 1940); male and female from Big Bend N.P., Tuff Canyon; ZFMK Kra60 (male) and ZFMK USA18 (female). A. Tarsal organ on male left tarsus 1. B. Tarsal organ on male left tarsus 2. C. Tip of male left tarsus 3, showing position of tarsal organ (arrow). D. Tarsal organ on male left tarsus 4. E. Tarsal organ on female left tarsus 1. F. Tarsal organ on female left tarsus 3. Scale lines: 2 µm (A, E–F); 10 µm (B–D).

FIGURE 10. Chisosa diluta (Gertsch & Mulaik, 1940), from Big Bend N.P.; female from Hot Springs (A, D, E), ZFMK USA20; and two females from Tuff Canyon (B, C, F–I); ZFMK USA26. A–C. Abdomens, ventral views. D, F, H. Cleared genitalia, ventral views. E, G, I. Cleared genitalia, dorsal views. Note slight genitalic variation, especially in distance between pore plates. Abbreviation: pp, pore plate. Scale lines: 0.2 mm.