Philonthus quadraticeps Boheman, 1858

Chani-Posse, Mariana, 2010, Revision of the southern South American species of Philonthus Stephens (Coleoptera: Staphylinidae) 2595, Zootaxa 2595, pp. 1-70 : 45-47

Philonthus quadraticeps Boheman, 1858

( Figs. 13, 105–110, 152; Figs. 16–21 in Chani-Posse 2004)

Philonthus quadraticeps Boheman,1858: 28 ; Lynch-Arribálzaga, 1884: 150 (characters); Bernhauer & Schubert, 1914: 352 (catalog); Bruch, 1915: 445 (catalog); Blackwelder, 1944: 134 (list); Frank, 1982; 43 (list); Herman, 2001b: 2928 (catalog); Chani-Posse, 2004: 224–227 (characters), 231 (list).

Philonthus tenebrosus Boheman, 1858: 28 ; Lynch-Arribálzaga, 1884: 149 (characters, Argentina); Bernhauer & Schubert, 1914: 357 (catalog); Bruch, 1915: 445 (catalog); Scheerpeltz, 1933: 1363 (catalog); Blackwelder, 1944: 135 (list); Herman, 2001b: 2977 (catalog); Chani-Posse, 2004: 231 (list); Chani-Posse de Maus 2009: 35 (syn)

Diagnosis. Philonthus quadraticeps may be identified by its body shape and coloration, the eyes distinctly shorter than temples seen from above, the distance separating medial interocular punctures on frons about three times as large as distance separating medial punctures from lateral punctures, and the dorsal rows of punctures on pronotum each with four punctures. It differs from other southern South American species of Philonthus by the absence of a postmandibular ridge and the transverse distance between punctures on elytra distinctly larger than diameters of punctures.

Redescription. Length of the body 5.9–7.8 mm. Coloration. Head castaneous-piceous to black; thorax castaneous-brunneous; elytra castaneous-brunneous to testaceo-brunneous; abdominal segments castaneouspiceous to castaneous-brunneous with apical margins lighter; antennae, palpi and legs castaneous-brunneous to brunneous.

Head distinctly to slightly wider than long (HW/HL= 1.4–1.1) and at basal third as wide as distal third in both sexes, about as wide as pronotum (HW/PW= 1.0–0.94); dorsal surface coarsely and moderately punctate, with three to four postocular punctures and three to four epicranial punctures; distance separating medial interocular punctures on frons about three times as large as distance separating medial punctures from lateral punctures; infraorbital ridge present, extending not far beyond postgenal ridge; postmandibular ridge absent. Eyes distinctly shorter than temples (EL/TL= 0.74–0.6) seen from above. Antennae with segment 1 as long as segments 2 and 3 combined, segments 2 and 3 subequal in length, segments 4–6 quadrate, segments 7–10 transverse. Maxillary palpus with segment 2 not swollen, no more than twice as long as its maximum width; last segment fusiform, about 1.5 times longer than segment 3. Submentum about 1.5 times as long as mentum. Labial palpus with last segment twice as long as preceding segment. Neck more than 0.5 times as wide as head at widest point (NW/HW= 0.7–0.6).

Pronotum about as long as wide to moderately longer than wide (PW/PL= 1.0–0.8), parallel-sided; dorsal surface of pronotum with two rows of punctures, each with four punctures. Hypomeron not visible in lateral view. Basisternum with medial longitudinal carina moderately developed, bulbous. Metasternum with circummesocoxal ridge broadly rounded medially. Elytra at sides moderately to distinctly longer than pronotum at midline (EtL/PL=1.4–1.2), distinctly longer than elytra along suture (EtL/Etl= 1.8–1.6); transverse distance between punctures distinctly larger than diameters of punctures ( Fig. 13). Both front and middle tarsi as long as front and middle tibiae; first segment of hind tarsus as long as segments 2 and 3 combined, and longer than last segment (S1/S5= 1.5–1.3). Abdominal terga moderately punctuate at basal area, distance separating punctures about equal to diameters of punctures; terga 2 and 3 with elevated area between basal lines punctuate, posterior basal line straight medially. Male sternum 7 with apical margin straight. Tergum 8 in both sexes with posterior margin arcuate.

Male genitalia. Sternum 8 deeply emarginate medio-apically. Tergum 10 truncate medio-apically ( Fig. 109), with two long subapical macrosetae and 8–10 short apical setae. Sternum 9 with a concave emargination apically, one long apical seta at each side ( Fig. 105). Aedeagus with median lobe gradually narrowed from apical third; apex of median lobe subacute (in dorsal view) and simple in its apical fourth (in lateral view); paramere divided into two branches along most of its length, both close to each other reaching four fifths of median lobe length, each with 3–5 sensory peg setae at apex ( Figs. 106–108). Internal sac without sclerotized structures.

Female genitalia. Tergum 10 similar to that of male. Second gonocoxite with 2–5 strong setae along its outer margin, with stylus and with two long apical setae ( Fig. 110).

Geographical distribution. Philonthus quadraticeps is currently known only from Argentina, Uruguay, Paraguay, Brazil and Bolivia (new record) ( Fig. 152).

Bionomics. Philonthus quadraticeps has been reported as a common species in manure (Lynch- Arribálzaga 1884; Chani-Posse 2004). Frank (1982) cites this species as parasitized by Laboulbeniales (Fungi, Ascomycetes).

Type material. Lectotype of Philonthus quadraticeps , ♂, “Type”, “Buen Ayr”, “Kinb”, “Typus”, “ quadraticeps Bhn. ”, “5374 E91”, “Naturhistoriska Riksmuseet Stockholm / Loan no 834 / 06”, “ Lectotype Philonthus quadraticeps Boheman, 1858 / Des. Chani-Posse de Maus 2008 ” ( NHRS).

Lectotype of Philonthus tenebrosus , ♂, “Type”, “Buen Ayr”, “Kinb”, “Typus”, “ tenebrosus Bhn. ”, “5373 E91”, “Naturhistoriska Riksmuseet Stockholm / Loan no 832/06”, “ Lectotype Philonthus tenebrosus Boheman, 1858 / Des. Chani-Posse de Maus 2008 ” ( NHRS). Paralectotype: ♂, “Buen Ayr”, “Kinb”, “ tenebrosus Bhn. ”, “5375 E91”, “Naturhistoriska Riksmuseet Stockholm / Loan no 833/06”, “ Paralectotype Philonthus tenebrosus Boheman, 1858 / Des. Chani-Posse de Maus 2008 ” ( NHRS).

Additional material: 110 specimens (21 ♂, 21 ♀, 68 unsexed)

ARGENTINA: Buenos Aires: Balneario, 24-XII-1918, Philonthus quadraticeps Boh. , 1 specimen ( MLPA); Caseros, III.1932, 1 specimen ( MLPA); La Plata, 5.X.19. Weiser, 1 specimen ( NMPC); Liniers, 10.I.1932, C. Bruch, Philonthus quadraticeps Boh. , 1 specimen ( MLPA); Tigre, 6-1938, M. J. Viana, in Bernhauer handwriting " quadraticeps Boh. Don. M. J. Viana ", det. Bernhauer; Chicago NHMus Bernhauer Collection, 1 ♂ ( FMNH); 14.X.1908, C. Bruch, Philonthus quadraticeps Boh. / in Bernhauer handwriting " quadraticeps ", det. Bernhauer, Chicago NHMus Bernhauer Collection, 2 specimens ( FMNH), 8 specimens ( MACN), 2 specimens ( MLPA), 15.X.1908, C. Bruch, Philonthus quadraticeps Boh. , 3 specimens ( NMPC); 1937, Field Mus. Nat. Hist. 1966 A. Bierig Collection, Acc. Z. 13812, 4 ♂, 3 ♀, 4 specimens ( FMNH). Catamarca: 19/ 24.II.1912, C. Bruch, in green card "Cotypus", Philonthus catamarcensis Bernh. / Philonthus quadraticeps , 3 specimens ( MLPA). Chaco: C. Bruch, 1 specimen ( MACN). Córdoba: C. Bruch, 1 specimen ( MLPA); Alta Gracia, XII-920, ex nido Acromyrmex heyeri , Philonthus quadraticeps Boh. , 2 specimens ( MACN); La Granja, C. Bruch, 1 specimen ( MACN); 1939, M. J. Viana, Chicago NHMus Bernhauer Collection, 1 ♂ ( FMNH). Entre Ríos: Palmar, I.1974, L. E. Peña leg., Field Mus. Nat. Hist., 1 ♀ ( FMNH). Jujuy: C. Bruch, 1 specimen ( MACN). La Pampa: Pico, C. Bruch, 1 specimen ( MLPA). Mendoza: Alvarez Condarco, III-79, Sergio Roig, 2 specimens ( IADIZA); Ciudad, Zoologico, V-VI-97, S. Roig, G. Debandi, 2 specimens ( IADIZA). Tucumán: El Cadillal, 22.VI.1998 y 5.I.1999, col. M. Chani Posse, 2 ♂, 3 ♀ ( IMLA). BOLIVIA: Santa Cruz: San Antonio nr. Charagua, IX, 1–6, 1960, B. Malkin Leg., 1 ♂ ( FMNH). BRAZIL: Rio Grande do Sul: Fortaleza, 26.VIII.25, 1 ♂ ( FMNH). Santa Catarina: Rio Vermelho, I-1945, A. Maller, Frank Johnson Donor, 1 specimen ( AMNH). Sao Paulo: Mraz LGT, in Bernhauer handwriting " Philonthus quadraticeps Boh. "/ in Bernhauer handwriting " v. mrazi Brnh. Typ. "; Museo Pragense, Chicago NHMus Bernhauer Collection, 5 ♂, 7 ♀ ( FMNH); J. Mráz, 10 specimens ( NMPC). PARAGUAY: Asunción: January- March, B. Podtiaguin, 5 ♂, 7 ♀, 14 specimens ( AMNH); 1885, in Bernhauer handwriting " quadraticeps Boh. ", det. Bernhauer, Chicago NHMus Bernhauer Collection, 1 ♂ ( FMNH). Guairá: Villarrica, April 1936, F. Schade, Blackwelder collection, 3 specimens ( AMNH). URUGUAY: Montevideo: Cerro, 12.X.33, in Bernhauer handwriting " quadraticeps ", det. Bernhauer, lg. Fernandez; Chicago NHMus Bernhauer Collection, 3 specimens ( FMNH).