<i>Metalibitia borellii</i> (Roewer, 1925) <p>(Figs 1 C; 3B; 5C, G; 7C, G; 11D–F)</p> <p> <i>Libitiola borellii</i> Roewer, 1925: 8 [desc], fig. 6; 1927: 611 [rdesc], fig. 41; 1938: 5 [cit]; B. Soares, 1945: 343 [cit]. <i>Metalibitia borellii</i>: Ringuelet, 1959: 420 [cit, rdesc, syst, “species inquirenda”]; Kury, 2003: 68 [cat]; Pinto-da Rocha & Hara, 2011: 3 [cit]</p> <p> <b>Type material.</b> MZT, “type”. Not examined. SMF RII 121/3, ♂ ♀ paratypes. Examined. SMF 1409, paratype. Examined.</p> <p> <b>Type locality.</b> BOLIVIA, <i>Tarija Department</i>: Aguairenda, San Francisco and Caiza.</p> <p> <b>Geographical distribution (Fig. 14).</b> Restricted to western and southern regions oF Bolivia (Chaco and Tarija).</p> <p> <b>Diagnosis.</b> Resembles <i>M. tibialis</i> in having one rounded retroapical tubercle on Femur IV (Figs 5 C, G; 6D, I); <i>M. argentina</i> in having Free tergite III central tubercle with rounded apex, larger than others (Figs 1 B, C) (<i>M. tibialis</i> has Free tergite III unarmed, see Fig. 2 D) and tibia IV unarmed (Figs 7 C, G) (<i>M. tibialis</i> has ventral apophyses, see Fig. 8 I). Distinguished From these species by cheliceral bulla having one retroapical tubercle (Fig. 1 C) (<i>M. argentina</i> and <i>M. tibialis</i> have two tubercles united at base, Figs 1 B; 2D), trochanter IV with two retroventral tubercles, one basal and one apical (Fig. 5 G) (<i>M. argentina</i> has a group oF Fused tubercles and <i>M. tibialis</i> has one high tubercle with rhomboid apex on apical region, Figs 5 F, 6I).</p> <p> <b>Redescription.</b> Male (MNRJ 1374)</p> <p> <i>Measurements</i> (SMF 121/ 3 paratype): dorsal scutum, total length 4.1; dorsal scutum, total width 4.05; prosoma length 1.3; prosoma width 2.25; Femur I length 1.75; Femur II length 3.2; Femur III length 2.75; Femur IV length 3.25; pedipalpal Femur length 0.85 mm.</p> <p> <i>Coloration in ethanol:</i> Entirely pale brown, legs slightly lighter than dorsal scutum.</p> <p> <i>Dorsum</i> (Fig. 1 C): Median region oF anterior margin oF dorsal scutum smooth with two high rhomboid tubercles Fused at the base, near paracheliceral projections. Ocularium with slight median depression, covered by small tubercles, especially on the posterior portion. Lateral margins oF dorsal scutum with rounded tubercles, From the ozopore up to scutal area IV. Median pair oF small spines on area IV with rounded apex. Posterior margin oF dorsal scutum with row oF 17 tubercles. Free tergite I with row oF 15 tubercles, II with row oF 12 tubercles, III with row oF nine tubercles, the median one highest, with rhomboid apex and directed dorsad. Anal operculum with 25 tubercles irregularly distributed. All tubercles oF posterior margin, Free tergites and anal operculum have rounded apex.</p> <p> <i>Chelicera</i> (Fig. 1 C): Bulla with Four tubercles with rounded apex on proximal margin, smaller tubercles on lateral borders, one single tubercle on proapical region. Segment II with Four teeth; segment III with Five minute teeth.</p> <p> <i>Pedipalps</i> (Fig. 3 B): Trochanter with two ventral tubercles. Femur with 10 median dorsal tubercles, six apical dorsal tubercles, and a row oF seven ventral tubercles with rounded apex (the three middle tubercles higher than the others in the same row). Tibia with small setiFerous tubercles, a rounded proapical projection, one tubercle on laterodorsoapical region, ventral lateral spines and one prolateral spine. Tarsus elongate, with Four ventral prolateral macrosetae and two ventral retrolateral macrosetae.</p> <p> <i>Legs</i> (Figs 1 C, 5C, G; 7C, G): Coxa I with one FalciForm prolateral tubercle reaching the apex oF coxa and one smaller basal retrolateral tubercle. Coxa II with prolateral tubercle with rhomboid apex directed towards apex oF the coxa and one smaller retrolateral apical rhomboid tubercle. Coxa III with one prolateral apical FalciForm tubercle. Coxa IV dorsally visible only at apex, tuberculate and with one dorsal proapical apophysis. Trochanter IV with one dorsal tubercle, two retroapical dorsal tubercles and retrolateral small tubercles, one retroventral basal tubercle, with the apex slightly curved upwards and one apical tubercle, with the apex slightly curved downwards. Femur IV curved and covered with small tubercles, high retroapical rhomboid tubercle, two ventral rows oF tubercles. Tibia IV covered with small tubercles, with two ventral rows oF small tubercles. Tarsal Formula: 5 / 6 / 5 / 6.</p> <p> <i>Penis</i> (Figs 11 D–F): Truncus enlarged at the base oF insertion oF ventral plate. Ventral plate elongated with wide U-cleFt at distal margin, two ventro-apical pairs oF macrosetae and two median-ventral pairs oF macrosetae E; two pairs oF apical macrosetae displaced laterally (group C). Two pairs oF small macrosetae on latero-median region (group D) and one proximal lateral pair (group B). Insertion oF glans on middle oF ventral plate. Glans short, with apical one third oF stylus narrower. Stylus long, with truncated apex.</p> <p>Female (SMF 121/3)</p> <p> <i>Measurements:</i> dorsal scutum, total length 3.95; dorsal scutum, total width 3.4; prosoma length 1.0; prosoma width 1.75; Femur I length 1.25; Femur II length 2.45; Femur III length 2.0; Femur IV length 2.75; pedipalpal Femur length 0.7 mm.</p> <p> <i>Dorsum:</i> Constriction between prosoma and opisthosoma oF dorsal scutum attenuated. Ocularium low, with shallow median depression. Posterior margin oF dorsal scutum with row oF 21 tubercles with pointed apices, one median pair oF tubercles highest. Free tergite I with 18 tubercles, II with 17 tubercles, III with 12–13 tubercles and without a larger median tubercle. <i>Legs:</i> Coxae with small tubercles, with pointed apices. Coxa IV with dorsoapical apophysis reduced. Trochanter IV without dorsal tubercle, entirely with small tubercles. Femur IV covered with small tubercles, without rounded retrolateral tubercle. Tibia with small tubercles, without ventral row oF small tubercles. Tarsal Formula: 5 / 6 / 5 / 6.</p> <p> <b>Variation.</b> Posterior margin oF dorsal scutum with two tubercles larger than others on their lateral sides. The retrolateral tubercle oF Femur can be less evident, trochanter IV can have retrolateral ventral tubercles straight, with pointed apex. <i>Measurements</i> ♂ (<i>n=4</i>): dorsal scutum, total length 3.4–4.1; dorsal scutum, total width 3.1–4.1; prosoma length 1.1–1.3; prosoma width 1.9–2.2; Femur I length 1.7; Femur II length 3.0–3.5; Femur III length 2.2– 2.9; Femur IV length 2.8–3.7; pedipalpal Femur length 0.8–1.0 mm. Measurements ♀ (<i>n=3</i>): dorsal scutum, total length 4.0–4.1; dorsal scutum, total width 3.3–3.6; prosoma length 1.1; prosoma width 1.9–2.0; Femur I length 1.4– 1.6; Femur II length 2.8–3.0; Femur III length 2.2–2.4; Femur IV length 2.8–3.0; pedipalpal Femur length 0.7–0.9 mm. Tarsal Formula ♂ (n=4): 4–5/ 5–7/ 5/ 5–6.</p> <p> <b>Material examined.</b> BOLIVIA. <i>Santa Cruz</i>, without locality 17°00'51.1"S 68°49'58.8"W, without date, without leg., 1♂ (MNRJ 1374); <i>Tarija</i>, Entre Rios, Paraíso del Tordo, 21°35'54.7"S 64°08'58.2"W, 05.XII.2010, R. Pinto-da-Rocha, A. Benedetti, J. Ochoa & A. Sarabia leg., 3♂ 5♀ (MZSP 67949).</p>Published as part of <i>Coronato-Ribeiro, Amanda & Pinto-Da-Rocha, Ricardo, 2017, Taxonomic revision and cladistic analysis of the genus Metalibitia Roewer, 1912 (Opiliones, Cosmetidae, Cosmetinae), pp. 201-242 in Zootaxa 4291 (2)</i> on pages 217-218, DOI: 10.11646/zootaxa.4291.2.1, <a href="http://zenodo.org/record/829489">http://zenodo.org/record/829489</a>