Ebonius Lewis, 1885

Degallier, Nicolas, Leivas, Fernando W. T. & Moura, Daniel P., 2011, Histerid beetles of French Guiana. V. Revision of the genus Ebonius Lewis (Coleoptera, Histeridae, Omalodini), Zootaxa 2824, pp. 44-52 : 46-47

Ebonius Lewis, 1885

Ebonius Lewis, 1885: 209 (description); 1893: 417 (illustration); 1905: 21 (catalogue); 1910: 51–52 (description of a new species); Bickhardt, 1910: 33 (catalogue); Lewis, 1914: 242 (illustration); Bickhardt, 1917: 153 –154 (morphological characters and geographical distribution); Blackwelder, 1944: 183 (catalogue); Kryzhanovskij, 1972: 19 (description of the tribe Omalodini ); Mazur, 1984: 227 (catalogue); Mazur, 1989: 37 (key to genera of Omalodini ); Mazur, 1997: 89 (catalogue); Kovarik & Caterino, 2005: 193 (catalogue).

Type species. Ebonius politus Lewis, 1885 (by monotypy)

Diagnosis. Body subcylindrical, almost parallel-sided; pronotum with antescutellar fovea, anterior and posterior angles rounded; prosternum broad, rounded at the base; carinal stria “U”-shaped; sutural region of elytra concave; protibiae with 5 or 6 teeth; first abdominal sternum with large punctuation on the posterior region, first abdominal sternum stria present anteriorly and laterally; propygidium and pygidium with deep punctuation; pygidium with a transverse elevation medially.

Redescription. Length (pronotum + elytra): 6.6–7.49 mm; width: 2.2–4.5 mm. Body subcylindrical, almost parallel sided; dark; shining ( Fig. 3 ).

Head with irregular, strong and dense punctuation; frontal disc with a deep impression in the middle; occipital, supraorbital and frontal striae well marked; frontoclypeal suture present laterally ( Fig. 2 A). Labrum subrectangular. The left mandible with a long tooth on the internal margin. Antennae with scape slender at the base; last antennomeres from funicle with lateral setae; antennal club with well-marked sutures and the last segment with an apical depression.

Pronotum subquadrangular, 1.4 times as wide as long, with slightly raised sides; punctuation dense and regular; anterior margin with a complete marginal stria ( Fig. 2 A); lateral stria complete, and laterally confluent with pronotal margin; posterior region with rounded edges and an antescutellar fovea ( Fig. 3 A, C, E). Prosternum with large punctuation, an orifice on each side of the anterior margin and near the procoxal cavities; prosternal keel large and flat; “U”-shaped carinal stria; posterior margin of prosternum rounded; prosternal lobe rounded in the middle of the anterior margin and marginal stria complete ( Fig. 3 B, D, F).

Elytra with well-marked striae, external subhumeral stria long; sutural region concave and sutural stria long ( Fig. 3 A, C, E). Mesosternum widely emarginated anteriorly; mesosternal marginal stria complete ( Fig. 3 B, D, F). Metasternum finely punctuated on the disc, with lateral metasternal stria complete and ending close to the metasternal-mesepimeral suture.

Anterior femur with strong and dense punctuation; anterior tibia with 5 or 6 teeth on the external margin; tarsal cavity straight. Meso and metatibiae with the apical tooth widened and adorned with four short spines, metatibiae with 3–4 teeth on the external margin.

First abdominal sternum with large punctuation on the lateral region and posterior margin, with a stria present along anterior and lateral margins ( Fig. 3 B, D, F). Propygidium and pygidium with irregular and deep punctuations, the latter with the anterior margin straight and a transverse elevation medially ( Fig. 2 B).

Female genitalia as observed in the type-species: coxites at least twice as long as wide ( Fig. 4 A), and with a subapical lateral projection next the cavity for insertion of stylus ( Fig. 4 A, B). Duct of spermatheca inserted on apical region of bursa copulatrix ( Fig. 4 C, D). Spermatheca elongated with constraining rings ( Fig. 4 D). Accessory spermatic gland elongated and bigger than spermatheca ( Fig. 4 C, D).

Male genitalia as observed in the type species: eighth tergite 1.3 times as long as wide, basal margin emarginated and feebly emarginated apically, without apical stria ( Fig. 5 B); eighth ventrite composed of two sclerites, transversely cut and not pilose apically ( Fig. 5 A); ninth tergite elongated and pointed apically ( Fig. 5 D); ninth ventrite not "Y"-shaped, sclerotized and bilobed apically ( Fig. 5 C); tenth tergite bilobed apically, not setose ( Fig. 5 D); aedeagus straight, feebly curved at the apex, 9.9 times as long as wide at base of parameres, which are fused basally and dorsally separate on their apical fourth, becoming translucid and expanded ( Fig. 5 E, F); basal piece 0.36 times as long as the parameres ( Fig. 5 E); gonopore of internal tube with its border finely serrated.

Remarks. Ebonius differs from other Neotropical genera of Omalodini in the following combination of characters: body cylindrical almost parallel-sided; antennae with subtriangular club (oval in Scapomegas and Sphyracus ); prosternum large, rounded at base (emarginated in Scapomegas and truncated in Sphyracus ) and with carinal stria “U”-shaped (never “U”-shaped in other Omalodini ); anterior margin of mesosternum widely emarginated (when compared to Omalodes ); post-mesocoxal stria absent (present in Sphyracus and in some species of Scapomegas ); sutural region of the elytra concave (flattened or weakly depressed in Scapomegas , Omalodes and Sphyracus ); stria of the first abdominal sternum present anteriorly and laterally (absent on the anterior margin in other Omalodini ); propygidium without tubercules (present in Cornillus of Omalodes ) and pygidium with a transverse elevation in the middle, both structures with large and deep punctuation (mostly with smaller and shallow punctuation in Omalodes , Scapomegas and Sphyracus ); male genitalia very similar to that illustrated by Leivas (2009: figs. 136–138, 143) for Omalodes (Diplogrammicus) .

Distribution. The species of Ebonius are limited to northern South America, being found in the following localities: French Guiana (Bélizon, Kourou, Montagne des Chevaux, Réserve des Nouragues, Itoupé – Mont tabulaire), Brazil (Pará and Amazonas) and Ecuador (Canelos, Pastaza and Napo).

Figures

FIGURE 2. Ebonius politus Lewis, 1885 photographs A. Frontal view; B. Pygidium.

FIGURE 3. Dorsal and ventral habitus photographs of type material and type labels. A-B. Ebonius politus Lewis, 1885; C-D. Ebonius lineiger (Marseul, 1870); E-F. Ebonius aequatorius Lewis, 1910.

FIGURE 4. Ebonius politus Lewis, 1885, female genitalia. A. Coxites, ventral view, scale 1 mm.; B. Detail of stylus, scale 0.5 mm.; C. Bursa copulatrix, vagina, spermatheca and accessory spermatic gland, scale: 0.5 mm.; D. Detail from spermatheca and accessory spermatic gland, scale: 0.25 mm.

FIGURE 5. Ebonius politus Lewis, 1885, male genitalia. A. Eighth ventrite, dorsal view; B. Eighth tergite, dorsal view; C. Ninth ventrite, dorsal view; D. Ninth and tenth tergites, dorsal view; E. Edeagus, lateral view; F. Detail from parameres of the aedagus, ventral view. Scale: 0.5 mm.