Potosa, GOODNIGHT & GOODNIGHT, 1947

Cruz-López, Jesús A. & Francke, Oscar F., 2015, Cladistic analysis and taxonomic revision of the genus Karos Goodnight & Goodnight, 1944 (Opiliones, Laniatores, Stygnopsidae), Zoological Journal of the Linnean Society 175 (4), pp. 827-891 : 862

POTOSA GOODNIGHT & GOODNIGHT, 1947 STAT. REV.

Potosa Goodnight & Goodnight, 1947: 7 .

Karos: Goodnight & Goodnight, 1953: 20 (in part. Generic synonymy transfer by implication).

Distribution: Central region of the Sierra Madre Oriental in eastern Mexico, specifically in southern San Luís Potosí and northern Hidalgo.

Type species: Potosa dybasi Goodnight & Goodnight, 1947 , by original designation.

Included species: Potosa dybasi and Potosa reddelli sp. nov.

Diagnosis: Scutum Ming vase-shaped ( Figs 35B , 38B ). Ocularium in the middle of prosoma, low, with or without median armature. ( Figs 35C , 36C , 38C , 39C ). Metatarsus I in males swollen and with ventral glandular openings ( Figs 36B , 39B , 60A, B ). Male genitalia: pars distalis slightly constrained at the base, near to basal-most pair of lateral setae. Apical margin nearly straight. Three to five pairs of lateral setae, short, basal pair or basal two pairs separated from the rest. Three to four pairs of ventral microsetae, noticeably separated into two groups, basal (one or two pairs) and distal (two pairs). Two pairs of parastylar setae completely basal (below) to follis. Follis slightly longer than wide. Spiniform projections not exposed, but visible. Lateral projection of follis robust, pointed ( Figs 37 , 40 ).

Comparisons: The presence of a ventral glandular opening on metatarsus I in males is a remarkable synapomorphy of this genus. Inside the family, this is

Figures

Figure 35. Potosa dybasi. A, habitus, dorsal view. B, scutum, dorsal view. C, ocularium, frontal view. Scale bars: A = 3.5 mm, B = 1.5 mm, C = 0.5 mm.

Figure 36. Potosa dybasi. A, leg IV, mesal view. B, leg I, mesal view. C, scutum, lateral view. D, habitus, ventral view. Scale bars: A = 2 mm, B–D = 1 mm. Arrow in (B) indicates the glandular opening. The dark lines on (D) indicate the stigmatic area.

Figure 37. Potosa dybasi, male genitalia. A, dorsal view. B, ventral view. C, lateral view. White arrows indicate ventral microsetae in (B) and parastylar setae in (A).

Figure 38. Potosa reddelli sp. nov. A, habitus, dorsal view. B, scutum, dorsal view. C, ocularium, frontal view. Scale bars: A = 3.5 mm, B = 1.5 mm, C = 0.5 mm.

Figure 39. Potosa reddelli sp. nov. A, leg IV, mesal view. B, leg I, mesal view. C, scutum, lateral view. D, habitus, ventral view. Scale bars: A = 2 mm, B–D = 1 mm. Arrow in (B) indicates the glandular opening. The dark lines on (D) indicate the stigmatic area.

Figure 40. Potosa reddelli sp. nov. male genitalia. A, dorsal view. B, ventral view. C, lateral view. White arrows indicate ventral microsetae in (B) and parastylar setae in (A).

Figure 60. A, ventral view of metatarsus I in male of Potosa dybasi; arrow indicates glandular opening. B, ventral view of metatarsus I in male of Potosa reddelli sp. nov.; arrow indicates glandular opening. C, swollen apical portion on femur II in male of Huasteca gratiosa. D, ventral view of pars distalis of Karos barbarikos; arrows indicate ventral microsetae. E, detail of ventral microsetae of pars distalis of Karos projectus. F, ventral view of pars distalis of Karos singularis sp. nov.; arrows indicate ventral microsetae. G, detail of apical portion of follis of Montabunus foliorum; arrow indicates the lateral projection of follis. H, detail of apical portion of follis of Chapulobunus poblano sp. nov.; arrow indicates the lateral projection of follis. I, apical portion of follis of Chapulobunus unispinosus; arrow indicates the lateral projection of follis.