Eunausibius tenebrionoides (Grouvelle)

Halstead, David G. H., 2020, New and little known Coleoptera (Silvanidae: Silvaninae) from Central and South America, Insecta Mundi 2020 (842), pp. 1-37: 27

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Eunausibius tenebrionoides (Grouvelle)


Eunausibius tenebrionoides (Grouvelle)  

( Fig. 91–94 View Figures 91–97 )

Nausibius tenebrionoides Grouvelle 1896: 193   (type examined).

Eunausibius tenebrionoides (Grouvelle)   ; Grouvelle 1913: 314.

Diagnosis. See “Diagnosis” for Nausibius jatahyensis   new species, a very similar species.

Description. Eunausibius tenebrionoides   is known only from the male holotype. Length 6.4 mm, elongate, total length to elytral breadth ratio 43.8:10.0, general appearance sub-cylindrical, dark brown, moderately shining, dorsum glabrous.

Head. Slightly transverse (10.0:10.9), moderately raised medially on anterior half, slight depressions above antennal insertions, punctures small and separate on middle of head becoming larger and confluent laterally towards eyes; eyes in dorsal view flat, small, length: head length, 10:36, separated from front of head by 2× length of eye; antenna with 4-segmented club, last segment small, first antennal segment hidden beneath genal margin.

Pronotum. Elongate, 13.3:10.0; lateral margins straight, parallel; lateral rim fine, inwardly produced as very short fine line below anterior angle; anterior angle slightly curved before apical margin; densely punctured, punctures confluent producing predominantly longitudinal rugosity, particularly obvious laterally where punctures become obsolete (pronotum without an obvious medial, longitudinal impunctate region).

Elytra. Elongate, 24.4:10.0, sub-cylindrical, glabrous (at least in type); 9 rows of punctate striae on each elytron, including 2 on lateral declivity; interstriae mostly with single row of very small punctures, surface uneven with deep micro-reticulation as in E. jatahyensis   ; arrangement of elytral punctures similar to that of E. jatahyensis   (see Fig. 102 View Figures 98–102 ) but setae absent; fine impressed line present along sutural side of first punctate stria, near elytral apices ( Fig. 91 View Figures 91–97 ).

First abdominal ventrite. Femoral line strongly produced, extending to apical third of ventrite ( Fig. 92 View Figures 91–97 ).

Legs, male. Metafemora with extremely small tooth, all tibiae with fine striae on inner side ( Fig. 91 View Figures 91–97 ).

Male genitalia. ( Fig. 93–94 View Figures 91–97 ) With median strut and internal sac similar to E. elongatus   (see Fig. 108 View Figures 103–110 ), also rods similar but 25–26 on each side; median lobe short, deeply emarginate and with 4 comparatively long setae on each side; parameres moderately long, setae present along outer margin and apical third of inner margin, those at apex very long ( Fig. 94 View Figures 91–97 ); sternites 8 and 9 transverse, 8 rounded at sides, not produced ( Fig. 93 View Figures 91–97 ).

Taxonomic notes. The specimen in the MNHN labelled as “tenebrionoides” also “ Eunausibius tenebrionoides   ” by Grouvelle, and bearing an old printed “Type” label (as other Grouvelle types) is a male (as figured by Grouvelle in the original description). It has the character states described by Grouvelle, of which the pronotal puncturation is particularly significant, but the locality of Bahia, which is on the specimen, is wrong for that recorded by Grouvelle (1896) who gives “Matusinhos (Minas Geraes)”. However, the specimen is here accepted as the holotype because there is no evidence to suggest that Grouvelle based his description on more than one specimen and the published locality record seems to be a mistake.

Material examined. Holotype male “ S. Antonio da Barra Pr. de Bahia Gounelle 11-12. 88 [printed] / Type [printed] / Nausibius tenebrionoides Grouv.   [handwritten on squared paper] / tenebrionoides Grouv.   [Grouvelle’s handwriting on green label] / Eunausibius tenebrionoides Grouv.   [Grouvelle’s handwriting on green label]” ( MNHN).  

Distribution. Brazil.


Museum National d'Histoire Naturelle














Eunausibius tenebrionoides (Grouvelle)

Halstead, David G. H. 2020

Eunausibius tenebrionoides (Grouvelle)

Grouvelle A. 1913: 314

Nausibius tenebrionoides

Grouvelle A. 1896: 193