Oedichirus exilis, Herman, 2013

Herman, Lee H., 2013, Revision Of The New World Species Of Oedichirus (Coleoptera: Staphylinidae: Paederinae: Pinophilini: Procirrina), Bulletin of the American Museum of Natural History 2013 (375), pp. 1-137 : 78-80

Oedichirus exilis , new species

Figures 40 , 129–134

TYPE MATERIAL: Holotype: Male. ‘‘ Brazil, Rio de Janeiro: Silva Jardim March 1974 F.M. Oliveira/ Holotype Oedichirus exilis Herman. ’’ Deposited in the American Museum of Natural History. (Left metatibia and metatarsus are missing.)

TYPE LOCALITY: Brazil: Rio de Janeiro: Silva Jardim (22 ° 399S, 42 ° 239W). ( Silva Jardim is ENE of the city of Rio de Janeiro in the south central region of the state; the coordinates are from Paynter and Traylor, 1991: 605) .

DIAGNOSIS: The species is part of a complex that also includes O. clavolateralis , O. clavulus , and O. geniculatus . Males of the complex have a short, wide, asymmetrical emargination of sternum VIII (figs. 94, 102, 132, 147) and the aedeagus has a stout, tapered and curved apicoventral process arising from the apical or lateroapical margin of the ventral sclerite and protrudes to the right (figs. 90, 99, 130, 142). For O. exilis the apicoventral process is strongly flattened and directed anteriorly more strongly than for the other species, with the possible exception of O. clavulus (fig. 99). The median lobe of O. exilis has a short, blunt, posteriorly directed knob that extends from the right lateral side of the ventral sclerite (fig. 129); O. geniculatus (figs. 141) lacks a knob at that position. Along with O. exilis , both O. clavolateralis (fig. 89) and O. clavulus (fig. 98) have a knob in a similar position. For O. clavulus (fig. 98) the knob is a long, cylindrical, blunt peg. The knob extending from the lateral dorsal region of the apicoventral process of O. exilis (fig. 129) is wider basally and more strongly tapered and the gap between the knob and the base of the apicoventral process wider than for O. clavulus (fig. 98) for which the peg is more gradually tapered and the gap between it and the base of the apicoventral process is narrower. For O. clavolateralis and O. exilis the knobs are similar. However, the apicoventral process of O. exilis is strongly directed anteriorly (fig. 130), only moderately wide in posterior view (fig. 134), and the posterior margin of the ventral sclerite is broadly rounded and lacks a lobe. Whereas for O. clavolateralis the apicoventral process is directed laterally and the apex is pointed anteriorly (fig. 90), the apicoventral process is broad in posterior view (fig. 92), and the posterior margin of the ventral sclerite has a lobe (fig. 90).

DESCRIPTION: Length: 6.9 mm. Length of head: 0.8 mm. Width of head: 1.1 mm. Pronotal length: 1.2 mm. Pronotal width: 1.0 mm. Elytral length: 1.0 mm. Elytral width: 1.1 mm.

Body pale reddish brown (teneral specimen). Legs bicolored yellowish brown with pale reddish brown femorotibial maculation.

Head about two fifths wider than long (HW/HL 5 1.4). Frontoclypeal ridge strongly curved, incomplete with medial ends widely separated. Dorsal surface without Vshaped depression; surface with microsculpturing anteriorly adjacent to frontoclypeal ridge and remainder of surface polished; punctation coarse and dense anteriorly and medially and sparse near neck; subbasal region impunctate medially. Labrum quadridentate; surface without tubercle near submedial denticle.

Pronotum about one fifth longer than wide (PL/PW 5 1.2). Pronotum polished, with coarse, moderately dense punctation and moderately large impunctate spots; surface with deep, submedial punctate groove on basal two thirds. Elytra about one tenth wider than long (EW/EL 5 1.1); surface flat medially and coarsely punctate.

Abdominal terga III to V densely punctate and without transverse rows of punctures; tergum VI less densely punctate and tergum VII sparsely and less coarsely punctate. Segment III without paratergite; paratergal carina present and extending slightly beyond spiracle. Tergum III without median point extending from transverse basal ridge. Tergum VIII with apically open median point extending from transverse basal ridge; posterior margin slightly rounded. Tergum IX with lateroapical process about three times longer than midbasal length (LLaP/T9: 3.1), moderately bent ventrally, and diverging slightly from other process; ventromedial margin without posteriorly directed spur (cf. fig. 158).

MALE: Sternum VI and VII unmodified. Sternum VIII with wide, moderately deep, asymmetrical emargination of posterior margin (fig. 132), emargination about one sixth of length of sternum, wider than deep, base broadly rounded, and positioned mostly to left of midlongitudinal line; right margin of emargination shorter and more steeply sloped than left; surface adjacent to margin of emargination translucent and beveled and with a few fine setae along edge of bevel; median surface slightly flattened; long setae evenly distributed; surface laterad of emargination with small cluster of short, spinelike setae; transverse basal ridge without median point and irregularly sinuate. Tergum IX with anteroventral angle extended anteriorly as large process. Sternum IX (fig. 133) slightly asymmetrical; anterior margin narrow and strongly rounded; posterior margin broadly rounded; right margin broadly rounded; left margin slightly sinuate.

Aedeagus asymmetrical (figs. 129–131). Ventral sclerite with apical margin broadly rounded to left of apicoventral process (fig. 130), with large, flattened, curved, strongly sclerotized apicoventral process extending from right lateroapical margin; apicoventral process broad and strongly tapered to dorsally directed, acute apex and process directed lateroanteriorly; ventral sclerite with wide, short, dorsoventrally flattened, blunt knob extending posteriorly from right side of apical margin at base of apicoventral process (fig. 129). Parameres moderately broad basally, flattened, tapered and slender apically, fused to median lobe for most of length and free of median lobe near apex; left paramere laying against lateral and ventral surfaces (figs. 130, 131), right paramere against lateral surface and with apical portion strongly curved ventrally (fig. 129); parameres of approximately equal length.

FEMALE: Unknown.

ETYMOLOGY: The name is from the Latin exilis , ‘‘thin, slender, narrow,’’ and refers to the narrow, compressed apicoventral process of the aedeagus.

DISTRIBUTION: Known from only one locality in the state of Rio de Janeiro (fig. 40).

REMARKS: The specimen is teneral and, although the pale integument is firm, the aedeagus is lightly sclerotized and pigmented and the basal bulb is collapsed. The femorotibial maculation is pale and perhaps appears to be absent, but, like other species of the complex, I expect it will be dark in fully pigmented individuals.

Figures

Figs. 39–40. Oedichirus species. Distribution. 39. Mesoamerica and the Caribbean. 40. South America. (Species described prior to present work preceded with *. Symbols ³ or ♀ signify species known only by the sex indicated. Open circle denotes multiple collecting sites.)

Figs. 129–134. Oedichirus exilis. 129. Aedeagus, right lateral. 130. Aedeagus, ventral. 131. Aedeagus, left lateral. 132. Sternum VIII, male. 133. Sternum IX, male. 134. Aedeagus, apex, posterior.