Plochionocerus Dejean, 1833

Asiain, Julieta, Márquez, Juan & Morrone, Juan J., 2007, Phylogenetic systematics of the genera Plochionocerus Dejean and Agrodes Nordmann (Coleoptera: Staphylinidae: Xantholinini), Zootaxa 1584, pp. 1-53 : 9-10

Plochionocerus Dejean, 1833

Plochionocerus Dejean, 1833: 64 (non Sharp, 1885) (type species: Staphylinus violaceus Olivier, 1795 , by monotypy); Blackwelder, 1952: 360; Herman, 2001: 3743 (catalog).

Sterculia Laporte, 1835: 118 (type species: Staphylinus violaceus Olivier, 1795 , by original designation); Erichson, 1839: 301; Laporte, 1840: 180; Erichson, 1847: 88 (synonym of Agrodes ); Lacordaire, 1854: 66 (synonym of Agrodes ); Gemminger & Harold, 1868: 599 (catalog); Sharp, 1876: 186; Duvivier, 1883: 155 (catalog); Bernhauer & Schubert, 1914: 314 (catalog); Scheerpeltz, 1933: 1320 (catalog); Blackwelder, 1944: 149 (checklist); Blackwelder, 1952: 360 (synonym of Plochionocerus ).

Araeocnemus Nordmann, 1837: 163 (type species: Staphylinus fulgens Fabricius, 1793 , subsequent designation by Duponchel & Chevrolat, 1842); Erichson, 1839: 301 (cited as Araeocnemis ; synonym of Sterculia ); Lacordaire, 1854: 66 (synonym of Agrodes ); Gemminger & Harold, 1868: 599 (synonym of Sterculia ); Casey, 1906: 359 (cited as Araeocnemis ); Bernhauer & Schubert, 1914: 314 (synonym of Sterculia ).

Plociocerus Agassiz, 1847: 299 (unjustified emendation of Plochionocerus ) (type species: Staphylinus violaceus Olivier, 1795 , by objective synonymy with Plochionocerus ); Blackwelder, 1952: 315 (synonym of Plochionocerus ).

Callictenus Chevrolat, 1848: 24 (nomen nudum); Blackwelder, 1952: 89 (synonym of Sterculia ).

Diagnosis. Body with metallic, bright coloration; head with lateroventral furrows ( Figs. 11–15 ); ventral surface of the head with expanded, umbilicate punctures ( Figs. 50, 51, 53 ; except P. hermani ); labrum with a pair of lateral teeth and a pair of central teeth longer than the lateral ( Figs. 35, 36 ; except P. marquezi , Fig. 34 ); mandibles longer than half of the head length; labial apical palpomere widened toward apex, which is truncated obliquely ( Figs. 43, 46, 47 ); upper line of the pronotal hypomeron completely developed (or only absent in the anterior third), not directed ventrad and conspicuously separated from the lower line ( Fig. 63 ); pronotal hypomeron glabrous (except P. marquezi ); hind margin of each elytron with central notch ( Fig. 59 ); and internal margin of the tibiae with brush of dense setae ( Fig. 62 ).

Redescription. Total length 13.2–30.0 mm. Body with metallic, bright, blue, violet, green, golden or red coloration, sometimes with combined colors.

Head. Variable in shape (rounded, rectangular or elongate), dorsally with black setae and dense, umbilicate punctures ( Figs. 1, 2 , 19 ); ventral surface smooth, with expanded, umbilicate punctures variable in density, sometimes combined with fine punctures ( Figs. 50, 51, 53 ); lateroventral surface with furrows, lateroventral furrows smooth with irregular row of setiferous punctures near dorsal margin of each furrow ( Figs. 11–15 ); antennae with basal antennomere longer than antennomeres 2+3 combined, second antennomere shorter than third, remaining antennomeres shorter than second and of variable shape ( Figs. 24–31 ); anterior margin of labrum with two lateral teeth and two central teeth longer than the lateral ( Figs. 35, 36 ); mandibles pointed, longer than half of length of head, left mandible with two teeth, right with one, channel on the basal, external half present or absent ( Figs. 1, 2 , 7 , 19 , 63 ); first maxillary palpomere shorter than second to fourth, second longest, third almost as long or slightly longer than apical palpomere and slightly widened toward apex, apical palpomere conical ( Figs. 43–47 ); first labial palpomere shorter than second and third, second as long or slightly shorter than apical and slightly widened toward apex, apical palpomere conspicuously widened toward apex and obliquely truncated, truncate apical zone with fine sensillae ( Figs. 43, 46, 47 ). Neck narrow, normally with anterior corners pointed ( Fig. 68 ).

Thorax. Pronotum smooth; with fine and dispersed setiferous punctures, with a central longitudinal area without punctures ( Figs. 1, 2 , 56, 57 ); lateral margins slightly sinuated in posterior half; lateroposterior half of pronotum with variably developed, depressed area ( Figs. 56, 57 ); upper line of pronotal hypomeron completely developed (or only partially absent in anterior third), not directed ventrad and conspicuously separated from the lower line ( Fig. 63 ); surface of pronotal hypomeron glabrous. Scutellum with scarce punctures. Elytra slightly longer than pronotum (except P. pronotalis ); surface smooth, with dense setiferous punctures; fore margin with central depression or notch variably developed ( Fig. 59 ). Prosternum transverse, subpentagonal ( Fig. 68 ); slightly carinate in middle, surface smooth and lacking setae (except P. marquezi ). Mesoventrite short and wide, surface smooth and with scarce setiferous punctures in fore margin. Metaventrite big, surface smooth and with scarce setiferous punctures.

Legs. Long and slender; femora with dispersed setae on internal and external surfaces, with strong and short setae aligned on lower margins, ventral surface flat; internal part of tibiae with brush of dense, white or gray setae ( Fig. 62 ), and apical spines, the internal one longer than the remaining; tarsomeres 1–4 gradually smaller toward apex, fifth tarsomere longest and almost as long as tarsomeres 2–4 combined.

Abdomen. Smooth and with punctures less dense than on elytra; fifth and sixth visible segments notably narrower than 1–4; pregenital sternite of male with more abundant setae than female; genital sternite in males elongate, asymmetrical and pointed toward apex, with setae in the hind part, wider than the genital tergite. Aedeagus. Generally symmetrical, variably shaped (elongate, cylindrical or pear-shaped).

Figures

FIGURES 9 – 16. Lateral view of head: 9, Philonthus testaceipennis; 10, Agrodes elegans; 11, Plochionocerus discedens; 12, P. gracilis; 13, P. humeralis; 14, P. m a rq u e z i; 15, P. simplicicollis; 16, Renda flagellicornis.

FIGURES 48 – 53. Cephalic ventral view: 48, Renda flagellicornis; 49, Philonthus testaceipennis; 50, Plochionocerus simplicicollis; 51, P. gracilis; 52, P. h e r m a n i; 53, P. puncticeps.

FIGURES 32 – 39. Labrum: 32, Homalolinus flavipennis; 33, Renda flagellicornis; 34, Plochionocerus marquezi; 35, P. simplicicollis; 36, P. puncticeps; 37, Agrodes elegans. Mandibles: 38, Agrodes conicicollis; 39, A. elegans.

FIGURES 40 – 47. Maxillary (a) and labial (b) palpi: 40, Philonthus testaceipennis; 41, Renda flagellicornis; 42, Agrodes elegans; 43, Plochionocerus impressipennis; 44, P. gracilis; 45, P. m a rq u e z i; 46, P. simplicicollis; 47, P. puncticeps.

FIGURES 63 – 66. Lateral view of pronotal hypomeron: 63, Plochionocerus simplicicollis; 64, Renda spp.; 65, Agrodes conicicollis; 66, A. elegans.

FIGURES 54 – 62. Pronotum: 54, Philonthus testaceipennis; 55, Renda flagellicornis; 56, Plochionocerus simplicicollis; 57, P. reticularis. Elytra: 58, Agrodes spp.; 59, Plochionocerus spp. Midleg: 60, Philonthus testaceipennis; 61, Agrodes spp.; 62, Plochionocerus spp.

FIGURES 1 – 6. Habitus, dorsal view: 1, Plochionocerus simplicicollis; 2, P. s p l e n d e n s; 3, Agrodes elegans; 4, Renda fimetaria; 5, Philonthus testaceipennis; 6, Homalolinus flavipennis. Scale bar 3 mm.

FIGURES 17 – 19. Dorsal view of head (a) and detail of punctation (b): 17, Philonthus testaceipennis; 18, Thyreocephalus puncticeps; 19, Plochionocerus simplicicollis.

FIGURES 20 – 31. Antennae: 20, Philonthus testaceipennis; 21, Renda flagellicornis; 22, Agrodes conicicollis; 23, A. elegans; 24, Plochionocerus gracilis; 25, P. humeralis; 26, P. i g n e u s; 27, P. m a rq u e z i; 28, P. puncticeps; 29, P. re t i c u - laris; 30, P. s p l e n d e n s; 31, P. transversalis.

FIGURES 7 – 8. Measurements scheme: 7, Dorsal view of Plochionocerus simplicicollis (a: total length of body, b: mandible length, c: head length, d: maximum width of head, e: pronotum length, f: anterior width of pronotum, g: posterior width of pronotum, h: elytral length); 8, aedeagus of Plochionocerus discedens (a: total length of aedeagus, b: apical area of median lobe, c: basal area of median lobe, d: paramere length).

FIGURES 67 – 68. Ventral view of anterior part of body: 67, Agrodes conicicollis; 68, Plochionocerus splendens.