Pectenobunus colliculosus ( Roewer, 1925 ), 2004

Tourinho-Davis, Ana Lúcia, 2004, The third South American species of the genus Pectenobunus Roewer, with a new synonymy for the genus (Opiliones, Eupnoi, Sclerosomatidae, Gagrellinae), Zootaxa 405 (1), pp. 1-16 : 7-9

Pectenobunus colliculosus ( Roewer, 1925) , comb. nov.

( Figs. 1–7 , 10–11, 14 , 16 )

Caiza colliculosa Roewer, 1925: 32 ; Mello­Leitão 1938: 322 Ringuelet 1954:287; Ringuelet 1959: 217; Roewer 1953: 185.

Material Examined: 1 ♂ 1 ♀ paratypes (Roewer identified both as females) SMF R II/ 346/144, Bolivia, Chaco .

Type locality: Bolivia; (Chaco) .

Distribution: South America: Bolivia, Caiza (Chaco) ( Fig. 16 ).

Emended diagnosis. Body uniformly brown ( Figs. 1–4 ), including legs. Eye mound armed with two rows of seven spines ( Fig. 7a ). Abdominal scute with two to three blunt processes sharply marked in both sexes ( Figs. 3–4 , 7 ). Shaft of penis more than two times longer than alate portion ( Fig. 10 ).

Redescription. Male: lengths: body 4.6 mm, prosoma: 1.1 mm, abdominal scute: 2.9 mm, chelicerae: 1.6 mm, pedipalps: 2.5 mm. Legs femora I–IV: 3.5 mm; 7.2 mm; 3.9 mm; 4.0 mm. Color: ventral surface brown, pedipalps and chelicerae cream. Dorsal and ventral surface with large reticulations forming alveoli ( Figs. 1a ), segments slightly separated one from the other ( Figs. 1–2 ). Supracheliceral laminae armed with two or three­pointed sharp granules. Eye mound armed with two rows of seven spines, each tipped with three points ( Fig. 7a ). Chelicerae: ventro­basal spine of basichelicerite sharp ( Fig. 5–5a ). Pedipalps ( Fig. 6 ): ventral face of trochanter armed with sharp­pointed granules irregularly placed. Femur armed ventrally with longitudinal rows of sharp­pointed granules. Patella either unarmed or armed with dorsolateral sharp­pointed granules, inner apophysis of patella unarmed, as wide as long. Tibia densely armed with sharp­pointed spines disposed irregularly. Tarsus unarmed. Legs: femoral formula 0/2/0/0. Penis: Winglets narrow (longer then wide) distal portion straighter, without projections, outline of winglets not very sinuous ( Figs. 10–11, 14 ). Female: Measurements: body 8.7 mm, carapace 1.1 mm; abdominal scute: 3.3 mm, chelicerae: 1.6 mm; pedipalps: 2.5 mm. Color: As in the male ( Figs. 2, 4 ). Dorsal and ventral view, chelicerae, pedipalps and legs: As in the male.

Remarks. Roewer (1953) stated that this species also occurs in western Ecuador, although this distribution is probably too widespread for a gagrellinae species. Due to the high endemism observed in other Gagrellinae , it is possible that the specimen from Ecuador, is a misidentification of another species showing very similar external morphology. The generic groups established by Roewer and those that followed ( Ringuelet 1954, 1959, 1963; Soares 1972; Mello­Leitão 1931, 1938) are cluttered with species without any phylogenetic meaning, obscuring the knowledge about the diversity of the subfamily and its distribution ( Capocasale 1967; Tourinho & Kury 2000, 2001, Tourinho­Davis 2003). According to Roewer (1910, 1923, 1953) Holcobunus nigripalpis , the type species of the genus, was distributed in tropical and subtropical South America, and the genus Holcobunus was recorded from scattered localities throughout the Neotropics. The tropical and subtropical South American species assigned to Holcobunus were recently revised ( Tourinho & Kury, 2001), and it was shown that the genus includes only two endemic species of the western Rio de Janeiro state and eastern São Paulo state. Twelve Southern South American species of Holcobunus , nine species of Prionostemma and one species of Geaya are being transferred to other genera (further information on Neotropical Gagrellinae in Tourinho 2000; Tourinho & Kury 2001; Tourinho­Davis 2003; Tourinho­Davis & Kury 2003). Among the South American species of Gagrellinae studied up to now, a more widespread distribution occurs only in Jussara rosea = Holcobunus roseus ( Tourinho­Davis & Kury 2003) , from Brazil (Espírito Santo, Minas Gerais and Rio de Janeiro) and in P. paraguayensis ( Argentina, Paraguay, Uruguay). In North America Trachyrhinus marmoratus Banks, 1984 ranges from almost Canada to central Mexico, both Jussara and Trachyrhinus were revised by Tourinho­Davis & Kury (2003) and Cokendolpher (1981) and their genitalia studied and described. The distribution of P. paraguayensis can not be confirmed in this paper because only the specimens from Paraguay and Uruguay were examined. The wide distribution of P. paraguayensis was noted by different authors ( Mello­Leitão 1938; Roewer 1953; Ringuelet 1959) before the work of Capocasale (1967). Only Capocasale used the morphology of the genitalia as diagnostic characters.

Often the species of Gagrellinae have very similar color pattern and external morphology ( Holcobunus argentatus and Holcobunus luteovariatus ; Prionostemma farinosum , Prionostemma U­sigillatum and Holcobunus dentatus ), but a closer examination of these characters reveals some slight differences, and the examination of the penis may confirm the specific and generic identity more precisely. As what happens with species of Holcobunus , Jussara , Prionostemma and Geaya , some of the specimens identified as P. paraguayensis may in fact represent different species very similar to P. paraguayensis . To confirm the distribution of P. paraguayensis a comparison of the color pattern and both external and genital morphology of all specimens from each locality is needed.

Figures

FIGURE 16. Western South America showing distribution of the three nominal species of Pectenobunus Roewer. P. paraguayensis (triangles), P. ruricola (square), P. colliculosus (circles). This map includes Paraguay, Uruguay, part of Argentina, Bolivia and Brazil. Dotted lines = countrys and state boundaries, thin lines = rivers.

FIGURES 1–5. Pectenobunus colliculosus (Roewer). (paratypes SMF RII/346/144). Male: 1, dorsal view; 1a, detail showing the sculpture of the tegument; 3, male, lateral view; 5, right chelicerae showing ventrobasal spine in the detail; Female: 2, dorsal view; 4, lateral view. Scale bars = 1.0 mm for Figs 1–4; = 0.5 mm for Fig 5.

FIGURES 6–9. Fig. 6. P. colliculosus (Roewer). Male (SMF RII/346/144). 6, right pedipalp, lateral view. Scale bar = 1.0 mm. Figs 7–9. Schematic view of Pectenobunus species showing (by the arrows) the armature of the eye mound and the variation in protuberances on the abdominal scute. 7–7a, P. colliculosus; 8–8a, P. paraguayensis; 9–9a, P. ruricola, protuberance indicated by the arrow.

FIGURES 10–15. Figures 10–11, 14. P. colliculosus. Male (SMF RII/346/144), Penis, 10, ventral view; 11. lateral view; 14, anterior half, ventral view. Figures 12–13,15. P. paraguayensis. Male, (SMF R I/4/573), penis, 12, ventral view; 13, lateral view; 15 anterior half, ventral view. Scale bars = 0.5 mm for Figs 10–11, 12–13; = 0.25 mm for Figs. 14–15.