Karos tersum, Cruz-López & Francke, 2015

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 : 852-854

KAROS TERSUM SP. NOV.

( FIGS 21–23 , 59 , 61C , 62A , 63G )

Karos parvus: Goodnight & Goodnight, 1971: 35 (in part).

Type material: MEXICO: San Luís Potosí: ♂ holotype ( CNAN-T0725 ) and 2 ♀ paratypes ( TMM 37.129 ) (39. vii.1970; D. McKenzie), (lat 22.11639°, lon −99.16917°). Municipio Ciudad Valles, La Cueva de la Llanura, 4.8 km W Micos (previously designated as paratypes of Karos parvus by Goodnight & Goodnight, 1971) .

Material examined: MEXICO: San Luís Potosí: 1 ♀ [ CNAN (13.ii.2011; O. Francke, A. Valdez, C. Santibáñez, J. Cruz and G. Contreras)], (21°37′48″N, 99°03′ 38.73″W). Municipio Aquismón, Cueva de El Sol , Mantetzulel .

Etymology: From the Latin tersum (smooth), referring to the reduction in dorsal ornamentation of the scutum.

Diagnosis: Troglomorphic species. Sexual dimorphism of scutum unremarkable ( Fig. 21B ). Tubercles of transversal rows III and IV very small, mesotergal area II with only a few central tubercles ( Figs 21C , 63G ). Spines of the ocularium small, close to each other but not fused at their bases ( Fig. 22C ). Sexual length of femur ratio II: 1.42 and IV: 1.47. Metatarsus II with three clear annuli in males, two in females. Dorsoectal apophyses of coxa IV present, increasing in size distally, similar in both sexes. Male genitalia: apical margin convex. Lateral setae with cylindrical bases, flattened distally. Two pairs of parastylar setae, lateral to follis, basal pair slightly separated from follis base. Spiniform projections barely visible ( Fig. 23 ).

Description: Male holotype: Measurements: scutum length 3.3, maximum scutum width 2.7. Legs. I 2.00/ 0.75/1.55/2.10/, II 3.55/1.35/3.20/3.50, III 2.45/0.80/ 2.00/2.55, IV 3.90/1.25/3.45/3.80. Dorsum. Eyes slightly pigmented ( Fig. 21B ). Dorsum almost smooth, area II with only a few, small central tubercles, complete rows only on areas III and IV, tubercles small, except the central, which is spiniform ( Fig. 63G ). Spines of ocularium short, close to each other ( Fig. 22C ). Lateral clear areas on scutum triangular-shaped, clear areas on mesotergal area V apices and free tergites I and II, small, spiniform. Venter. Densely covered with spiniform tubercles. Row of tubercles on coxa I longer than those of the other coxae. Coxa IV most densely covered by tubercles. Dorsoectal apophyses of coxa increasing in size distally. Pedipalps. Patella with two mesodistal tubercles. Legs. Ornamentation similar on all legs, covered by small spiniform tubercles ( Fig. 22A ). Posterior legs slightly thicker than anterior ones. Metatarsus II with three inconspicuous clear annuli. Femur III curved. Tarsal count 4(2):8(3):6:6. Male genitalia. Apical margin convex. Lateral setae basally cylindrical, distally flattened, basal pair small and ventrally displaced. Parastylar setae lateral to follis. Spiniform projections not exposed, but visible ( Fig. 23 ). Female paratype: Measurements: scutum length 3.2, maximum scutum width 2.5. Similar to male, with the following differences: mid-bulge shorter, giving scutum appearance of being slightly rectangular, sexual proportion of femora to metatarsi: II 1.42/1.42/1.56/1.52 and IV 1.47/1.78/1.56/1.40 ( Figs 21A , 22A ). Metatarsus II with two inconspicuous clear annuli. Tarsal count 4(2):7(3):5– 6:6.

Natural history: The female collected in ‘Cueva de El Sol, Mantetzulel’ did not exhibit thanatosis behaviour, unlike other stygnopsids ( Cruz-López & Francke, 2013a, b).

Taxonomic accounts: Goodnight & Goodnight (1971) designated some specimens as paratypes of Karos parvus from localities other than the type locality, which proved to be incorrect. Karos tersum sp. nov. is one of these incorrectly ‘paratyped’ samples, and it is clearly different from Karos parvus . The new species is troglomorphic and quite pale in colour, has an almost smooth dorsum, and has the spines of the ocularium close to each other at the bases.

Figures

Figure 21. Karos tersum sp. nov. A, habitus, dorsal view. B, scutum, dorsal view. C, habitus, lateral view. Scale bars: A = 3.8 mm, B = 1.5 mm, C = 1 mm.

Figure 22. Karos tersum sp. nov. A, legs IV, mesal view. B, habitus, ventral view. C, ocularium, frontal view. Scale bars: A = 3.4 mm, B = 2.0 mm, C = 0.5 mm. The dark lines on (B) indicate the stigmatic area.

Figure 23. Karos tersum sp. nov. male genitalia. A, dorsal view. B, ventral view. C, lateral view. White arrows indicate ventral microsetae in (B) and parastylar setae in (C).

Figure 59. Distribution map of the species of the Karos genus-group, continued. White circles with black outline, Karos tersum sp. nov.; white circles with blue outline, Karos projectus; white circles with red outline, Karos singularis sp. nov.; black squares, Huasteca gratiosa comb. nov.; white square with black outline, Huasteca silhavyi sp. nov.; white square with red outline, Huasteca rugosa comb. nov.; black circles, Karos barbarikos.

Figure 61. A, detail of one of the lateral clear areas forming tubercles on scutum of Crettaros santibanezi sp. nov. B, detail of one of the lateral clear areas projected in tubercles on scutum of Karos singularis sp. nov. C, detail of one of the lateral clear areas projected in tubercles on scutum of Karos tersum sp. nov. D, detail of one of the lateral clear areas projected in tubercles on scutum of Huasteca silhavyi sp. nov. E, detail of one of the lateral clear areas projected in tubercles on scutum of Montabunus foliorum. F, detail of one of the lateral clear areas projected in tubercles on scutum of Monterella tuberculata. G, extra row of pegs in Chapulobunus poblano sp. nov., indicated by arrows. H, dorsal apophyses on trochanter II in male of Karos singularis sp. nov. I, detail of mesotergal areas III and IV in Montabunus foliorum; dotted lines indicate the sulcus between these areas. J, detail of mesotergal areas III and IV on Chapulobunus unispinosus; dotted lines indicate the sulcus between these areas. These images are not at the same scale.

Figure 62. A, dorsal view of lateral clear areas forming tubercles of Karos tersum sp. nov.; arrows indicate the clear areas. B, dorsal view of lateral clear areas projected in tubercles of Huasteca silhavyi sp. nov.; arrows indicate the clear areas. C, lateral view of posterior scutum of Karos singularis sp. nov., showing the spiniform tubercles. D, lateral view of posterior scutum of Montabunus foliorum, showing the rounded tubercles. E, dorsal view of row of pegs in Karos barbarikos; some pegs are indicated by black dots. F, dorsal view of row of pegs in Hoplobunus boneti; some pegs are indicated by black dots. These images are not at the same scale.

Figure 63. A, dorsal view of the anal bulge on Chapulobunus poblano sp. nov.; arrow indicates the bulge. B, lateral view of Huasteca silhavyi sp. nov., line indicates the very high lateral channel area. C, laterodorsal view of scutum of Crettaros valdezi sp. nov., showing the median humps on areas II and III indicated by dotted circles. D, posterodorsal view of scutum of Crettaros santibanezi sp. nov., showing the median humps on areas II and III indicated by dotted circles. E, dorsal view of trochanter IV of Karos barbarikos; arrow indicates the tridentate apophysis. F, anterodorsal view of scutum of Karos barbarikos, the black points mark the tubercles forming a ‘V’. G, dorsal ornamentation of Karos tersum sp. nov. showing the transversal row of tubercles on mesotergal areas; transversal row II indicated by black dots. H, detail of the ventral ornamentation on femur IV of Karos barbarikos. I, detail of the ectal ornamentation on tibia IV of Karos barbarikos; arrows indicate the spiniform tubercles. J, detail of the ventral ornamentation on leg IV in Chapulobunus poblano sp. nov. K, detail of the two apical spines on femur IV in Chapulobunus poblano sp. nov. These images are not at the same scale.