Osoriellus debilis ( SHARP, 1887 ) Irmler, 2014

Irmler, Ulrich, 2014, The Neotropical species of the genus Osoriellus FAGEL, 1959 (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 64 (2), pp. 231-354 : 264-266

Osoriellus debilis ( SHARP, 1887) new combination

( Figs 73 A-C, 100D)

Osorius debilis SHARP, 1887: 681

Type material examined: Panama: Chiriqui, Volcan de Chiriqui , leg. Champion (syntype in BMNH) .

Further material examined: Mexico: Chiapas, Union Juarez, NE slope Volcan Tacana, Rio de Finca Muxbal , from freshly cut stump, much sap, peeling bark, 1430 m elevation, 26.12.1975, leg. H. Frania ( AMNH) ; Ruinas de Palenque , nr. Group IV, stump litter, 1 male, 1 female, 6.4.1971, leg. C. Alteri ( AMNH) ; Palenque, Ruines , 3 specimens, 6.04.1974, C.H. Curran ( AMNH) ; San Louis de Potosi, Sierra de la Abra, Sotano de la Tinaja , flood debris on mud, slope, 500 m from entrance, 2 males, 1 female, 18.2.1970, leg. J.A.L. Cook ( AMNH) ; same location, but 500 m in cave, 16.3.1972, leg. J.A. Cook ( AMNH) ; Veracruz, 34 km N of Maolinco , 1280 m elevation, 21.- 22.4.1978, leg. Henry, Schaffner & Schuh ( AMNH) ; Nayarit, Tepic , 1 specimen, 7.08.1947, B. Malkin ( AMNH) ; Chajul, Selva Lacandona, Rio Lacatun , swebt & beaten, 1 specimen, 26.06.1996, leg. L.S. Mahunka ( NMB) ; Oaxaca, Oaxaca City , stream bank in tropical forest (partly sifting), 9 specimens, 12.11. + 16.11.1989, leg. R. Baranowski ( SMNH) ; Belize: Orange Walk Dist. Rio Bravo Conservation Area, La Milpa Field Station , flight interc., 1 specimen, 25.5.1997, leg. C.E. Carlton ( KNHM) ; Guatemala: 1 male, leg. Conradt, without more data ( SDEI) ; Honduras: Cortés, Parque Nacional Cusuco , 5 km N Buenos Aires (88°13'W, 15°29'N), oak/pine cloud forest, Malaise trap, 1 female, 15.08.1995, leg. R. Cave ( SMNH) ; El Paraiso, 6.9 km W Yuscarán, Cerro Montserrat (86°24'W, 13°55'N), forest litter, 1760 m elevation, Berlese , 1 specimen, 27.7.1994, leg. R. Anderson ( KNHM) ; Nicaragua: Matagalpa, 6 km NW, Selva Negra, Fountain Youth Trail (85°54.53'W, 12°59.99N), 1450 m elevation, flight interc., 1 specimen, 22.5.2002, leg. R.W. Brooks, Z. Falin, S. Chatzimanolis ( KNHM) ; Costa Rica: Puntarenas, 35 km NE San Vito, nr. Las Alturas, trail to Echandi , 2000 m elevation, beyond trail marker, litter near stream, 13 males, 23 females, 19.3.1991, leg. L. Herman ( AMNH) ; same location, but under bark of logs, female, 20.3.1991, leg. L. Herman ( AMNH) ; 35 km NE San Vito, nr. Las Alturas, trail to Cerro Enchandi , 2200 m elevation, beyond trail marker 30, litter near stream, 2 females, 19.3.1991, leg. L. Herman ( AMNH) ; Las Cruzes, Biol. Stat. (82°57.58'W, 8°47.14'N), 1330 m elevation, flight interc., 3 specimens, 28.5.- 30.5.2004, 28.5.- 31.5.2004, leg. J.S. Ashe, Z. Falin & I. Hinojosa ( KNHM) ; Altamira Biol. Stn . (83°00.49'W, 8°56.17'N), 1510-1600 m elevation, flight interc., 4 specimens, 4.- 7.6.2004, leg. J.S. Ashe, Z. Falin & I. Hinojosa ( KNHM) ; Las Alturas Biol Stn . (82°50.01'W, 8°56.17'N), 1660 m elevation, flight interc., 3 specimen, 3.6.2004, leg. J.S. Ashe, Z. Falin & I. Hinojosa ( KNHM) ; Rincon de Osa (83°31.11'W, 8°41.14'N), 50 m elevation, flight interc., 1 specimen, 26.6.2001, leg. S. & J. Peck ( KNHM) ; Corcovado National Park, Sirena Stn. lower Ollas Trail (83°35.22'W, 8°24.48'N), 5 m elevation, flight interc., 2 specimens, 24.- 28.06.2000, leg. Z.H. Falin ( KNHM) ; same location, but Rio Pavo Trail , flight interc., 3 specimens, 25.- 28.6.2000, leg. Z.H. Falin ( KNHM) ; Monteverde, Boehme House , pitfall trap, 1400 m elevation, 1 specimen, 24.5.1989, leg. J.S. Ashe, R. Leschen, R. Brooks ( KNHM) ; same location, flight interc., 1 specimen, 31.5.1992, leg. M.E. Jameson ( KNHM) ; Finca La Pacifica (85°08'W, 10°27'N), dry forest leaf litter, 40 m elevation, 17.07.1988, leg. L. Longino ( KNHM) ; Heredia, Puerto Viejo de Serapiqui, La Selva Biol. Station , female, 18.2.1985, leg. L. Herman ( AMNH) ; Puerto Viejo, 3 km S, La Selva (84°00'W, 10°25'N), 80 m elevation, flight interc., 1 specimen, 2.- 15.6.1996, leg. S. Haase-Statz & R. Hanley ( KNHM) ; Finca Zurqui (84°00.22'W, 10°02.57'N), 1490 m elevation, flight interc., 15.- 23.11.2001, R.W. Brooks ( KNHM) ; San José, female, leg. E. Schmidt ( AMNH) ; 2.4 km ENE Sn Gerardo de Riva (83°34.20'W, 9°28.47'N), 1700 m elevation, flight interc., 1 specimen, 11.6.2004, leg. J.S. Ashe, Z. Falin & I. Hinojosa ( KNHM) ; Cartago, Ref. Nac. de Faune Silvestre , 2.5 km E Stn. (83°46.82'W, 9°44.23'N), 1330 m elevation, flight interc., 1 specimen, 1.11.2001, leg. R.W. Brooks ( KNHM) ; Panama: Colon, Parque Nacional Soberania, Pipeline Rd. km 6.1, flight intercept trap, 7 specimens, 7.6.1995, 7.- 21.6.1995, leg. J.S. Ashe, R. Brooks ( KMNH, UIC) ; same location, but Pipeline Rd. km 2.0, km 5.3, km 4.1, 4 specimens, 23.5., 15.5., 16.5., 18.-19.5., 27.5.1995, leg. J. Jolly, C. Chaboo ( KNHM) ; Poterillo , female, 27.5.1934, Blackwelder coll ( AMNH) ; Chiriqui, NW Volcan (82°40.26'W, 8°49.16'N), litter near stream, 1410 m elevation, 2 males, 2 females, 16.5., 17.5.2001, leg. L. Herman & W. Opitz, ( AMNH) ; Barro Colorado, by Berlese sample, 1 specimen, 1.11.1952, leg. J. Zatek ( AMNH) ; Barro Colorado , 5 specimens, 1.12.1929, 19.12.1928, 23.12. + 25.12.1928, leg. C.H. Curran ( AMNH) ; Barro Colorado , 1 specimen, 16.11.1930, F.G. Lutz ( AMNH) ; Panama, Rd. to Cerra Campana , litter nr. stream, 1 specimen, 22.12.2001, leg. L. Herman ( AMNH) ; Canal Zone, Ciricito , male, 13.3.1930, coll. R. Blackwelder ( AMNH) ; Barro Colorado Isd. (79°51'W, 9°11'N), flight interc., 9 specimens, 7.7., 1.8., 6.8., 11.8., 16.8., 1994, leg. D. Banks ( KNHM) ; same location, 1 specimen, 27.7.2000, leg. S. Chatzimanolis ( KNHM) ; La Fortuna, Continental Divide Trail (82°12.0'W, 8°46.0'N), forest litter, Berlese, 1200 m elevation, 1 specimen, 9.6.1995, leg. R. Anderson ( KNHM) ; Venezuela: Aragua, Ocumare , 2.5 km NE (63°41.0'W, 10°03.0'N), flight intercept trap, 1 specimen, 4.- 18.7.1994, leg. T. Phillips ( KNHM) ; Columbia : without further data, labelled as O. fulvipes ( ZMHB) ; S. Am. Colombia, without further location, 3 females, 1937, leg. G. Dahl ( SMNH) ; Ecuador: Pichincha, Maquipucuna Station , 45 km NW Quito, 1600-1650 m elevation, flight intercept trap, male, 13.-14.Apr.1990, leg. C. Carlton & R. Adrave ( KNHM) .

Diagnosis: Concerning the shape of the pronotum, the species can be confused with O. schwarzi , O. rougemonti and related species. However, O. debilis is distinctly smaller. A few specimens of O. debilis were not longer than 4.9 mm. It resembles O. trapezoides in size, but the shape of the pronotum in O. trapezoides is more convergent; whereas in O. debilis the pronotal sides are smoothly curved and nearly subparallel in the anterior half. Large specimens of the species are also similar to small specimens of O. schwarzi . In O. schwarzi the microsculpture of the pronotum is isodiametric, whereas in O. debilis it is more longitudinal. In addition, the apical lobe of the aedeagus of O. debilis is more slender and with a rectangular angle in the upper half. In O. schwarzi the apical lobe is longer and thicker.

Description: Length: 4.9 – 5.4 mm. Colouration: Dark brown; elytra slightly lighter; legs and antennae reddish.

Head: 0.75 mm long, 1.0 mm wide; eyes slightly prominent; front edge of clypeus even with short granules at each angle; with large, but weak setiferous punctures; clypeus and vertex more densely punctate; at base of antennae impunctate; very weak isodiametric microsculpture; surface nearly polished.

Antennae with oblong second antennomere; as long as conical third antennomere; fourth to sixth antennomeres nearly quadrate; approximately half as long as third; slightly increasing in width; antennomeres 7 to 10 distinctly wider than preceding antennomeres, but more or less quadrate.

Pronotum: 0.95 mm long, 1.05 mm wide; widest at anterior angles; slightly narrowed in anterior two-third; distinctly convergent in posterior third; lateral margin fine; in dorsal aspect close to anterior angles invisible; setiferous punctures large and deeper than on head; punctures partly in irregular rows and coriaceous; on average, interstices between punctures half as wide as diameter of punctures, but laterally and posteriorly with sparser punctation; wide impunctate midline; with weak netlike microsculpture; microsculpture more distinct than on head; surface less shiny than on pronotum.

Elytra: 1.25 mm long, 1.15 mm wide; with irregular deep setiferous punctation; punctures slightly visible in deep coriaceous ground-sculpture.

Abdomen with dense but fine setiferous punctation; netlike microsculpture fine; surface moderately shiny.

Protibia: 0.72 mm long, 0.27 mm wide; with 9 spines at outer edge; spines not inserting on digits; WLR: 6.0; comb of inner emargination visible throughout its total length; posterior face densely covered by long yellow setae.

Aedeagus with apical lobe slender and at base in one line with basal lobe; curved in nearly rectangular angle in apical half; ending in obtuse apex; inner edge of apical lobe with few sensillae.

Figures

Fig. 73-78: Osoriellus-s. str.-group: Osoriellus frater (73), O. latipes (74); O. mexicanus (75), O. brevipennis (76), O. argentinus (77), O. crassus (78); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.