Cosmetus villarreali, Medrano & Kury & Martinez, 2021

Medrano, Miguel, Kury, Adriano B. & Martinez, Leonel, 2021, A fresh look at Cosmetus Perty, 1833 (Opiliones: Cosmetidae), with new synonymies and description of two new species from Colombia, Zootaxa 5004 (3), pp. 430-446 : 439-441

publication ID 10.11646/zootaxa.5004.3.2

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Cosmetus villarreali

sp. nov.

Cosmetus villarreali View in CoL sp. nov.

Figures 8 View FIGURE 8 A−D, 9A−H, 10A−C, 11.

Type data. ♂ holotype ( MPUJ _ ENT 47571) from Colombia, Chocó , Acandí , Capurganá , Vereda Los Rios, Jardín Botánico El Darién (8°38’23.1”N 77°21’01.5”W), 26.iv. 2007, 270 m, J. Amaya et. al leg GoogleMaps . ♂ ( MPUJ _ ENT 47572) and ♀ ( MPUJ _ ENT 47570) C. Caltra leg. with same data as the holotype GoogleMaps .

Etymology. In honor of Osvaldo Villarreal, an arachnologist who made important contributions to the systematics of Opiliones . Noun in the genitive case.

Diagnosis. Cosmetus villarreali sp. nov. differs from its congeners by having paired yellow spots in laterals of cephalothorax, posterior to ocularium, and by the shape of ventral plate of the penis: with a deep U-cleft and quadrangular latero-distal borders ( Fig. 10C View FIGURE 10 ), and by the combination of the following features: (1) dorsal scutum beta-type ( Fig. 8A, D View FIGURE 8 ), (2) spine narrow, acuminate and divided, only fused at the base, length of the spine (SL) slightly shorter than dorsal scutum length ( Fig. 8 View FIGURE 8 B−C), (3) femur IV long and unarmed, (4) male with hypertelic chelicerae, beta male has little incrassate chelicerae but larger than in female ( Figs 8A View FIGURE 8 , 9 View FIGURE 9 A−F), both forms of male with a triangular tooth in movable finger (6) coxa IV not visible in dorsal view and without groin warts ( Fig. 8A View FIGURE 8 ).

Description: Measurements. CL: 1.18; CW: 3.07; AL: 4.24; CW: 3.05; IOD: 0.80; FeI: 5.65; TiI: 3.73; FeII: 12.94; TiII: 10.06; FeIII: 9.04; TiIII: 4.19; FeIV: 8.21; TiIV: 6.08; SL: 2.40.

Body ( Fig. 8 View FIGURE 8 A−D). Median cosmetid (4 mm of body length) with slender legs. Outline of dorsal scutum type beta (β) with constrictions barely marked, with triangular ectal projections of cheliceral sockets. Scutal grooves not visible. All scutum unarmed, except for area III with two contiguous large spines fused in the base slanted backwards with a narrow base (a third of abdomen length). Abdomen uniformly granulate even over spine of area III and carapace poorly granulate, only some granules in the posterior region. Eyes slightly separated (one third of carapace width), ocularium with medial depression. Free tergites each with a transverse row of minute granules and anal operculum weakly granulate.

Legs ( Figs 8 View FIGURE 8 A−D, 9I). Coxa IV uniformly granulated excepted by a distal apophysis formed by some granules. All femurs straight and without ornamentation. Smooth claws III and IV. Tarsal counts: 7(3), 17(3)–?, 13, 15.

Chelicera ( Figs 8 View FIGURE 8 A−C, 9A−F). Basichelicerite tuberculated in basal and ectal sides, three tubercules bigger in ecto-basal corner. Two small tubercles in antero-mesal corner. Cheliceral hand incrassate, kidney-like, forming a dorsal protuberance. Fixed finger with a keel formed by seven six fused tubercles and movable finger with nine tubercles and basally with a triangular tubercle.

Pedipalps ( Fig. 9G, H View FIGURE 9 ). Trochanter with strong ventral process. Femur with dorsally convex with some setiferous protuberances, ventrally with a row of 18 setiferous tubercles and mesodistal process. Tibia wider at the apical third.

Color, in alcohol ( Fig. 8 View FIGURE 8 A−D). Body uniformly vivid yellow (pale in holotype) with two unpigmented dots in posterior laterals of carapace. Legs with the same color of dorsal scutum except for Ta and tarsomeres of legs I and II with darker coloration.

Male genitalia ( Fig. 10 View FIGURE 10 A−C). Ventral plate of penis, in dorsal view, wider at the base. Distal border remarkably concave. Stylus with a large distal caruncle, no stylar barbs visible. Tip of the stylus with a rounded dorsal process. Two pairs of MS C flattened and curved; two pairs of straight MS D, distal one stronger; two pairs of small MS A in basal portion of ventral plate grouped with basal MS D.

Dimorphism. Two types of males: alpha male with hypertelic chelicerae and beta male with slightly swollen chelicerae ( Figs 8 View FIGURE 8 A−D, 9A−F). Male with basitarsomeres incrassate ( Fig. 9I View FIGURE 9 ).


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