Philonthus bicoloristylus Chani-Posse, 2004

Chani-Posse, Mariana, 2010, Revision of the southern South American species of Philonthus Stephens (Coleoptera: Staphylinidae) 2595, Zootaxa 2595, pp. 1-70 : 14-15

Philonthus bicoloristylus Chani-Posse, 2004

(Figs. 1, 12, 28–30, 153; Figs. 1–8, Chani-Posse 2004)

Philonthus bicoloristylus Chani-Posse, 2004: 219 (characters), 230 (list).

Diagnosis. Philonthus bicoloristylus may be identified by the eyes longer than temples and the bicolored styli of tergite 9. It differs from other southern South American species of Philonthus by the antennal segment 10 quadrate, the pronotum about as long as wide, and the dorsal rows of pronotum each with five punctures.

Redescription. Length of the body 8.0– 9.3 mm. Coloration. Head black; thorax castaneous- brunneous, elytra castaneous-piceous; abdominal segments castaneous-piceous, styli of tergum 9 with basal portion testaceous and apical portion black; antennae castaneous-piceous, palpi and legs castaneous-brunneous.

Head about slightly to moderately wider than long (HW/HL= 1.3–1.1) (Fig. 1) and at basal third as wide as distal third in both sexes, about as wide as pronotum (HW/PW= 0.98–0.90); 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. Eyes moderately to distinctly longer than temples (EL/TL= 1.60–1.20) seen from above (Fig. 1). Antennae with segment 1 slightly shorter than segments 2 and 3 combined, segments 2 shorter than segment 3, segments 4–9 elongate, segment 10 quadrate. Maxillary palpus with segment 2 not swollen, more than twice as long as its maximum width (Fig. 1); last segment fusiform, about 1.5 times longer than segment 3. Submentum and mentum subequal in length. Labial palpus with last segment 1.4–1.8 times as long as preceding segment. Neck more than 0.5 times as wide as head at widest point (NW/HW= 0.7).

Pronotum about as long as wide (PW/PL= 1.00–0.96), slightly narrowed anteriad; dorsal surface of pronotum with two rows of punctures, each with five 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 about as large as to distinctly smaller than diameters of punctures ( Fig. 12). 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 about as long as last segment (S1/S5= 1.15–1.00). Abdominal terga moderately punctuate at basal area, distance separating punctures distinctly smaller than 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 truncate.

Male genitalia. Sternum 8 moderately emarginate medio-apically. Tergum 10 similar to that of P. argus , emarginate medio-apically, with two long subapical macrosetae and 2–6 apical setae (Fig. 3, Chani-Posse 2004). Sternum 9 similar to that of P. longicornis , moderately emarginate apically, with one long subapical macroseta and two apical setae at each side (Fig.2, Chani-Posse 2004). Aedeagus with median lobe gradually narrowed from base of paramere; apex of median lobe subacute (in dorsal view) and simple in its apical fourth (in lateral view); paramere elongate and entire, stick-like, reaching four fifths of median lobe length, with two lateral rows of sensory peg setae joined at apex ( Figs. 28–30). Internal sac with no distinctly sclerotized structures.

Female genitalia. Tergum 10 similar to that of male, wide and subangulate, slightly emarginated medioapically and with two apical setae (Fig. 7, Chani-Posse 2004). Second gonocoxite with 2–5 strong setae along its outer margin, and stylus with two long apical setae (Fig. 8, Chani-Posse 2004).

Geographical distribution. Philonthus bicoloristylus is known from northwestern and eastern Argentina (Tucumán, Entre Ríos) and Colombia ( Fig. 153).

Bionomics. According to Chani-Posse (2004), P. bicoloristylus is a common species in horse and cow droppings in northwestern and eastern Argentina.

Type material. Holotype, ♂, with labels: “ Argentina, Tucumán, El Cadillal,

5.I.1999 ” “col. M. Chani Posse ” “ HOLOTYPUS ” “det. Mariana Chani-Posse 2000” “Colección Inst.- Fundacion M. Lillo /(4000) - S. M. de Tucumán / Tucumán - Argentina ” ( IMLA) . Paratypes: 22 specimens, with labels: “ Tucumán / El Cadillal/ 22.VI.1998 y 5.I.1999 / col. M. Chani Posse ” “ PARATYPUS ” “det. Mariana Chani-Posse 2000” “Colección Inst.- Fundacion M. Lillo /(4000) - S. M. de Tucumán / Tucumán - Argentina ” , 1 ♂ 4 ♀ ( FMNH) , 11 ♀ ( IMLA) ; “ Argentina, Entre Ríos / Concordia, 19.XI.1998 / col. M. Chani Posse ” “ PARATYPUS ” “det. Mariana Chani-Posse 2000” “Colección Inst.- Fundacion M. Lillo /(4000) - S. M. de Tucumán / Tucumán - Argentina ” , 1 ♂, 4 ♀ ( IMLA) .

Additional material: 10 specimens (5 ♂, 1 ♀, 4 unsexed)

ARGENTINA: Tucumán: Siambon , VII. 1933, Philonthus bruchi Bernh. , 3 specimens ( MACN) , 1 ♂ ( MLPA) with additional green label “ Typus ”; Río de las Tacanas , VII. 1933, 1 specimen ( MLPA) .

COLOMBIA: Cali: Fassi, figulus Er. det. Bernh., Chicago NHMus Bernhauer Collection, 1 ♂ ( FMNH) . Canon del Mt. Tolima: Fassi, figulus Er. det. Bernh., Chicago NHMus Bernhauer Collection, 3 ♂, 1 ♀. ( FMNH) .