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

Cosmetus villarreali sp. nov.

Figures 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 . ♂ ( MPUJ _ ENT 47572) and ♀ ( MPUJ _ ENT 47570) C. Caltra leg. with same data as the holotype .

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 ), and by the combination of the following features: (1) dorsal scutum beta-type ( Fig. 8A, D ), (2) spine narrow, acuminate and divided, only fused at the base, length of the spine (SL) slightly shorter than dorsal scutum length ( Fig. 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 , 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 ).

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 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 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 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 ). 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 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 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 A−D, 9A−F). Male with basitarsomeres incrassate ( Fig. 9I ).

Figures

FIGURE 8A−D. Cosmetus villarreali sp. nov.: (A) male holotype (MPUJ_ENT 47571), dorsal view. (B) same, frontal view. (C) same, lateral view. (D). female paratype (MPUJ_ENT 47571), lateral view. Scale bars: 1 mm.

FIGURE 9A−I. Cosmetus villarreali sp. nov.: (A) alpha male, holotype (MPUJ_ENT 47571), left basichelicera, dorsal view. (B) same, left cheliceral hand, dorsal view. (C) beta male (MPUJ_ENT 47570), left basichelicera, dorsal view. (D) same, left cheliceral hand, dorsal view. (E) female (MPUJ_ENT 47572), left basichelicera, dorsal view. (F) same, left cheliceral hand, dorsal view. (G–I) alpha male (MPUJ_ENT 47571). (G) left pedipalp, tibia and tarsus, mesal view. (H) left pedipalp, femur and patella, ventral view. (I) left leg I, metatarsus and tarsomeres. Scale bars: 1 mm.

FIGURE 10A−C. Cosmetus villarreali sp. nov.: male (MPUJ_ENT 47570), penis. (A) dorsal view. (B) latero-dorsal view. (C) same, lateral view. Scale bars: 50 µm.