Karschia (Karschia) latuis Fan, Zhang & Zhang, 2024, sp. nov.

Karschia (Karschia) latuis sp. nov. Figures 1, 2A–E, 3–6, 11A, B. Type material. Holotype ♂ (MHBU-Sol-2024NMG-01), CHINA, Nei Monggol Autonomous Region, Alxa League, Alxa Left Banner, Helan Mountain National Nature Reserve, 39.6130°N, 105.7406°E, altitude 1637 m, 16.VI.2024, leg. Long Hao. Paratypes 1♂ (SWUC-Sol-TYPE-202401), 1♀ (SWUC-Sol-TYPE-202402), same data as holotype. 1♂ (MHBU-Sol-2024NMG-04), same locality of holotype, but 38.0249°N, 105.8904°E, altitude 1779 m, 2. VI.2024, leg. Long Hao; 1♀ (MHBU-Sol-2024NMG-05), same locality of holotype, but 38.8817°N, 105.6884°E, altitude 1513 m, 2. VI.2024, leg. Wenlong Fan; 1♂ (MHBU-Sol-2024NMG-06), same locality of holotype, but 38.8677°N, 105.7615°E, altitude 1740 m, 12. VI.2024, leg. Long Hao. Additional material examined. 5 juveniles (MHBU-Sol-2024NMG-07–11, same locality of holotype but 38.9727°N, 105.8492°E, altitude 1791 m, 21.VIII.2024, leg. Yutong Zhang. Etymology. The species-specific epithet is derived from the Latin word “latus”, meaning special wide triangular-shaped dorsal crest on male cheliceral fixed finger. Diagnosis. Males of Karschia (Karschia) latuis sp. nov. is here placed in the subgenus Karschia (Karschia) due to the lack of a dorsal cheliceral spine on the male fixed finger; instead, there is a low keel like Karschia (Karschia) kopetdaghica Gromov, 1998, and female possess triangular genital operculum, which cover the genital opening behind them, (Gromov 2003; Figs 4A–C; 6A–C). Karschia (Karschia) latuis sp. nov. differs from all other species in the genus by the presence of a special wide triangular-shaped dorsal crest on male cheliceral fixed finger (Fig. 4A, B; 6A, B). The new species can be further distinguished from other Karschia species by notches in the basal peg of flagellum (Figs 4C, 6C), and by the ctenidia on sternite IV broad, non-acicular (Figs 4F, 6E). Female genital operculum shape similar to Karschia (Karschia) birulae Roewer, 1934. However, it can be distinguished by the visibility of the genital opening, which located distal to the genital plates (Figs 5F, 6H). The genital operculum not heavily chitinized distally (Figs 5F, 6H). Description. Male (holotype). Measurements. Metric data as in Table 1. Radio: A/CP: 7.65; CL/ CH: 2.84. Colour (Figs 3A, B). Propeltidium color predominantly yellowish-brown, with yellowish median sulcus; ocular tubercle dark except for a median longitudinal light band. Chelicerae with manus predominantly bright yellow, with some black areas; limits between the setose and asetose areas often darkened; fingers reddish-brown, especially on the teeth. Meso-, metapeltidium and dorsal surface of opisthosoma yellowish-green, tergite color darkens. Ventral surface of opisthosoma yellowish-green, sternite color darkens. Ventral surface of prosoma uniformly faint yellow, sternum lighter than coxae. Pedipalps and legs yellow to brown; pedipalps progressively become darker towards the apex, such that the tarsus is nearly black. Malleoli whitish. Propeltidium (Fig. 3D). Propeltidium wider than long (i.e. ratio of PL/PW 0.75), with very thin, filiform setae and some bifurcated tip setae of different sizes perpendicular to the surface of the propeltidium; propeltidium with distinctly concave median sulcus. Ocular tubercle with four anterior medial spiniform setae, one central medial spiniform seta and two posteriors medial spiniform setae; the interocular distance slightly smaller than the length of the eyes. Cheliceral dentition and processes (Figs 3A, B, 6A, B). Fixed finger with median teeth series comprising three primary teeth (FP, FM and FD), graded as FP<FD<FM, plus one secondary FSM tooth and two secondary FSD teeth (distal one tiny); fondal series comprising profondal teeth series with five teeth (PFM, PFP, three tiny PFSP), and retrofondal teeth series with eight teeth (two RFA, RFM, RFP, four RFSP). Fixed finger mucron with a special wide triangular-shaped dorsal crest and apex (FT tooth) curved and hook-shaped, and without FST. Movable finger with median teeth series comprising two primary teeth (MM and MP), plus two secondary MSM (distal one tiny); mucron without prolateral flange. Cheliceral setose areas and stridulatory plate (Figs 3A, B, 6A, B). Retrolateral and dorsal surface of the manus with large bifurcated tip setae and short simple tip filiform setae (rlm series); retrolateral and dorsal surfaces of the fixed finger with simple tip setae of different sizes (rlf series); prolateral surface with an array of setal types, as follows: proventral distal setae (pvd) consisting of two rows of plumose setae, the ventral-most reaching the distal PFSP tooth and the dorsal-most reaching the prolateral interdigital condyle (pic); proventral subdistal setae (pvsd comb) forming a tuft with about 7–9 spindly setae; the promedial setae (pm) series made up of thin, barbed, simple tipped filiform setae; the proximal prodorsal area covered with 6–7 long, simple tipped, non-barbed thick setae (pdp); stridulatory apparatus indented in the middle, and without clear and well-developed ridge. Distal limit of the prolateral setose area of the movable finger reaching the MSM tooth; movable finger prodorsal (mpd) setal series consisting of plumose setae arranged in a rather staggered row, adjacent to abundant non-plumose setae of the movable finger promedial (mpm) and proventral (mpv) setal series. Cheliceral flagellar complex (Figs 3C, 6C). The flagellar complex consists of flagellum, flagellar complex plumose (fcp) setae, and flagellar complex subspiniform (fcs) setae. Flagellum partially rotatable, long (filiform), coiled, without lateral apophysis (a small protrusion on the proximal lateral side of the flagellum (see Fan et al. 2024: fig. 13C)); attached to the fixed finger via a short stalk situated in a deep alveolus, comprises three components: a distinct stalk, a basal peg with notches (as indicated by the line in Fig 4C), and an elongated filiform shaft. Flagellar complex plumose (fcp) setae (i.e. modified pvd) broadened, elongated (extends beyond FT), and situated directly ventral to the flagellum; flagellar complex subspiniform (fcs) setae with two acuminate subspiniform setae, typically swollen basally and situated dorsoproximal to the point of flagellar attachment, labeled, distal to proximal. Opisthosoma. Entire surface covered with almost adpressed fine setae and numerous long, curved, bifurcate setae and tergites with abundant setae. Opisthosoma with ctenidia present, on third and fourth sternites (spiracular sternite III and post-spiracular sternites IV) (Figs 3E, F, 6D, E). Sternite III with at least three posterior paramedian groups of needle-like ctenidia, being gradually larger towards the posterior margin; sternite IV with a row of 17 long and broad columnar ctenidia, which extending the succeeding sternite edge (Figs 3E, F, 6D, E). Pedipalps (Figs 11A, B). All segments covered with short fine setae and long, thick setae. Tarsus ventrally with seven short strong spiniform setae (one broken off) without symmetrical arrangement; metatarsus with nine ventral spiniform setae, 1/2/2/1/1/1/1 pattern (from distal to proximal) and densely packed papillae. Legs. Covered with long, thick setae and short setae. Leg Ⅰ without spiniform seta with two small claws. Tibiae II, III and IV with a pair of distal spiniform setae ventrally, tibiae II and III each with one distal spiniform seta dorsally. Metatarsi II and III with a series of three dorsal spiniform setae, a pair of distal spiniform setae ventrally and some paired short, thick, spiniform setae over their entire ventral surface, metatarsus IV also with these paired spiniform setae over its entire ventral surface and two distal spiniform setae ventrally. Female (paratype). Mostly same as males, except where noted. Measurements. Metric data as in Table 1. Radio: A/CP: 5.31; CL/ CH: 2.98. Colour (Figs 3C, D). Similar coloration as male; meso-, metapeltidium and opisthosoma lighter than male, may due to the different concentrations of preserving alcohol. Cheliceral dentition and processes (Figs 4A–D, 6F, G). Fixed finger with median teeth series comprising three well-developed primary teeth (FP, FM and FD), FD tooth smaller, FM and FP similarly sized, one secondary FSD and two FSM teeth, all secondary teeth smaller than primary teeth, distal FSM smallest; fondal series comprising profondal teeth series with four teeth (PFM, PFP, two tiny PFSP), and retrofondal teeth series with seven teeth (two RFA, RFM, RFP, three RFSP). Movable finger with median teeth series comprising two primary teeth (MM and MP), both similar in size, plus three MST, three MSM (proximal teeth very tiny) and six MSP teeth (proximal three teeth tiny). Cheliceral setose areas (Figs 4A, B, 6G). Mostly like male, expect the proventral distal setae (pvd) consisting of one row of plumose setae, the proximal prodorsal area covered with 5 long, simple tipped, non-barbed thick setae (pdp), and without flagellar complex plumose (fcp) setae. Opisthosoma. Entire surface covered with almost adpressed fine setae and numerous long, curved, bifurcate setae and tergites with abundant setae. Opisthosoma with ctenidia present, only on fourth sternites (post-spiracular sternites IV) (Figs 5G, 6I). Sternite IV with a row of 14 long and broad columnar ctenidia, which extends the succeeding sternite edge (Figs 5G, 6I). Genital operculum typical triangular-shaped and with clear demarcation between the plates; genital opening located distal to the genital plates, the rear edge of the genital sternite not heavily chitinized (Figs 5F, 6H). Pedipalps. Pedipalpal tarsus and metatarsus without spiniform setae and papillae. Legs. Same as in the male. Distribution and habitat. Karschia (Karschia) latuis sp. nov. is known around the Helan Mountain National Nature Reserve (Fig. 1). The Helan Mountain National Nature Reserve is a conservation unit located in the western portion of the Nei Monggol Autonomous Region. A