Philonthus stenocephalus Scheerpeltz, 1972

Chani-Posse, Mariana, 2010, Revision of the southern South American species of Philonthus Stephens (Coleoptera: Staphylinidae) 2595, Zootaxa 2595, pp. 1-70 : 57-60

Philonthus stenocephalus Scheerpeltz, 1972

( Figs. 132–138, 148)

Philonthus angusticeps Bernhauer, 1934: 118 (preoccupied, not Bernhauer 1933); Blackwelder, 1944: 134 (list); Scheerpeltz, 1972: 18 (syn. of stenocephalus ).

Philonthus stenocephalus Scheerpeltz, 1972: 18 (new name for angusticeps Bernhauer 1934 ); Herman, 2001b: 2966 (catalog); Chani-Posse, 2004: 231 (list).

Diagnosis. Philonthus stenocephalus may be identified, and distinguished from P. argus , by the character states given below.

Redescription. Length of the body 7.0– 8.5 mm. In most character states similar to P. argus , but different as follows: head black; thorax, elytra and abdominal segments castaneous-piceous to piceous and elytra piceous; antennae castaneous-piceous; palpi and legs castaneous. Head similar to that of P. bonariensis ; antennae with segments 2 and 3 subequal in length; maxillary palpus with segment 2 not swollen, no more than twice as long as its maximum width; mentum and submentum subequal in length.

Male genitalia. Sternum 8 moderately emarginate medio-apically, with two long subapical macrosetae at each side. Tergum 10 wide and subangulate, slightly emarginate medio-apically ( Fig. 133), with two long subapical macrosetae and six apical setae. Sternum 9 deeply emarginate apically, two long subapical macrosetae, and two apical setae at each side ( Fig. 132). Aedeagus with median lobe 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, leaf-like, reaching two thirds of median lobe length, with two lateral rows of sensory peg setae joined at apex ( Figs. 134–136). Internal sac without sclerotized structures.

Female genitalia. Tergum 10 acute medio-apically, with two long subapical setae and two apical setae ( Fig. 137). Second gonocoxite with 2–5 strong setae along its outer margin, and stylus with two long apical setae ( Fig. 138).

Geographical distribution. Philonthus stenocephalus is currently known from Argentina and Bolivia (new record) ( Fig. 148).

Bionomics. Scheerpeltz (1972) collected this species from soil material under stones near streams, and sifted grass from a prairie at the foot of the Mount Piltriquitron (Río Negro, Argentina, 350 m of altitude). No further information available.

Type material. Lectotype (here designated), ♂, with labels: “seriebus dorsal 4-punctatis” (pink), “ angusticeps Bernh. Cotypus don. Richter” (yellow label) “Chicago NHMus. /M. Bernhauer Collection”, “ Lectotype Philonthus stenocephalus Scheerpeltz, 1972 / Des. Chani-Posse de Maus 2008 ” ( FMNH). Paralectotype: ♀, with labels: “seriebus dorsal 4-punctatis” (pink), “ longicornis Gr. det. Bernhauer”, “ angusticeps Bernh. Typ. ";” (white label, in Bernhauer handwriting), “ angusticeps Bernh. Typus don. Richter” (yellow label) “Chicago NHMus. /M. Bernhauer Collection”,“ Paralectotype Philonthus stenocephalus Scheerpeltz, 1972 / Des. Chani-Posse de Maus 2008 ” ( FMNH).

Notes. Although references about the type locality and a male character are given in the original description, there is no indication about how many specimens were examined. The two specimens here studied agree with the description by Bernhauer (1934) and considered to have been syntypes prior to the present lectotype designation.

Additional material: 14 specimens (2 ♂, 4 ♀, 8 unsexed) ARGENTINA: Buenos Aires: 12. 1897, C. Bruch, Philonthus aeruginosus Er. , in Bernhauer`s handwriting " Philonthus aeruginosus Er. " , 1 specimen ( MACN). Catamarca: 29.11. 1907, C. Bruch, Philonthus longicornis Steph. / Philonthus catamarcensis Bernh ., 2 ♀, 2 specimens ( MACN) , 1 specimen

( MLPA). Jujuy: C. Bruch, Philonthus atriseriatus Bernh. , 1 specimen ( MACN) . Salta: 1930, Dr. L. Witte, 2 specimens ( MACN) ; Candelaria, VII. 1933, 1 specimen ( MLPA) . Tucumán: Siambon, VII. 1933, 1 ♀ ( MACN) ; San Pedro de Colalao, I.1994, 2 ♂, 1 ♀ ( FMNH) .