Eunausibius jatahyensis Halstead

Halstead, David G. H., 2020, New and little known Coleoptera (Silvanidae: Silvaninae) from Central and South America, Insecta Mundi 2020 (842), pp. 1-37: 28-30

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Eunausibius jatahyensis Halstead

new species

Eunausibius jatahyensis Halstead   , new species

( Fig. 95–102 View Figures 91–97 View Figures 98–102 , 125 View Figures 125–126 )

Diagnosis. Although externally E. jatahyensis   is very similar to E. tenebrionoides   , males are easily recognised by genitalia, most particularly the form of the parameres which are much longer than in E. tenebrionoides   and have a different setal arrangement (compare Fig. 97 View Figures 91–97 with 94). In addition, the sternites 8 and 9 differ (compare Fig. 96 View Figures 91–97 with 93). External characters include comparatively larger eyes than those of E. tenebrionoides   (at least of the holotype of that species) and the general facies of the new species being a little more robust than E. tenebrionoides   .

Description. Based on 8 specimens, including 3 males and 5 females (the type series).

Length, male holotype 7.31 mm, range including the other two males, 4.1–9.6 mm, females (rest of types) 3.71–7.47 mm. Elongate, males tend to be slightly more so than female but there is overlap, breadth to length ratios, males 38.2–44.5:10.0 and females 36.0–40.2:10.0, sub-cylindrical, dark brown, shining, appearing glabrous but very fine and short setae borne by all punctures on dorsum.

Head. Slightly to more obviously shorter than broad, ratio of length to breadth across eyes 10.0:11.4–15.3; slightly raised medially on anterior half, slightly depressed above antennal insertions; punctures fine on raised area of head, becoming larger towards sides and posterior, at sides separated by less than diameter, none confluent; eyes generally large, moderately flat, dorsally separated across head by 8.9–13.3× breadth of eye in dorsal view; temple very small; antenna short, with gradually developed 4-segmented club ( Fig. 99 View Figures 98–102 ), apical segment small; ventral side of head with deep convergent antennal grooves as in the other two known species ( Fig. 101 View Figures 98–102 ).

Pronotum. Elongate, males tending to be more so than females, length to breadth ratios, male 12.0– 13.8:10.0, females 11.0–12.1:10.0; lateral margins more or less straight and parallel; lateral rim fine, very weakly produced below anterior angle forming a short inconspicuous line ( Fig. 98–99 View Figures 98–102 ); anterior angle slightly curved to apical margin; posterior angle small but dorsally prominent; disc with longitudinal, narrow impunctate region present medially, extending from base or basal sixth to near apical fifth, very short and difficult to see in small specimens, rest of puncturation dense, laterally with many of punctures forming confluent groups producing longitudinal rugosity, interspaces more or less micro-reticulate.

Elytra. Sub-cylindrical, elongate 2.0–2.5× as long as broad; 9 rows of conspicuous punctate striae on each elytron, including 2 on lateral declivity; interstriae with fine even micro-reticulation and mostly with single row of fine punctures ( Fig. 102 View Figures 98–102 ) but, particularly in females, some regions with irregular double row; apical quarter of each elytron with fine impressed line along sutural side of first punctate stria.

Legs, male. Metafemora with tooth of moderate size and metatibiae striate on proximal side.

First abdominal ventrite. With femoral line angled to a variable degree, as or more than shown in Fig. 95 View Figures 91–97 , but not long as in E. elongatus   ( Fig. 104 View Figures 103–110 ).

Male genitalia. ( Fig. 96–97 View Figures 91–97 ) With median strut and internal sac similar to E. elongatus   (see Fig. 108–109 View Figures 103–110 ) but with 25–26 chitinous rods on each side; median lobe of moderate length, shallowly emarginate and with 4–5 short setae on each side; parameres long with long setae along apical two thirds of both margins, a few shorter ones nearer base ( Fig. 97 View Figures 91–97 ); sternites 8 and 9 appearing moderately elongate, sternite 8 produced at sides ( Fig. 96 View Figures 91–97 )

Material examined. Holotype male “ Jatahy Prov. Goyaz Brés[il]” ( MNHN, Paris).  

Paratypes (7): 1 female, “Mineiro Goyaz Brésil ” ( MNHN, Paris )   ; 1 female: “ BRAZIL: Minas Gerais Larvras- Campus UFLA at light xii 2001 Leg.FZ Vaz-de-mello.” ( FSCA)   ; 1 male and 1 female, “ BOLIVIA: Santa Cruz Amboro National Park Los Volcanes, c. 1000m 18° 06’: W 63° 36’ 29 / xi-12 / xii / 2004 / MV light Sheet on stream beach Barclay, M. V. L. & Mendel, H. BMNH(E) 2004-280 ( NHML); 1 female, “ BOLIVIA: Santa Cruz, 3.7 km SSE Buena Vista, Hotel Flora & Fauna , 405m 5-15-xi-2001 17° 29.949’ S GoogleMaps   ; 63° 33.152’ W coll. M. C. Thomas & B. K. Dozier tropical transition forest” ( FSCA)   ; 1 male, “ BOLIVIA S. Cruz Dpt. 4km Bermajo 10-12. xii 2015 Wappes Kuckartz & Skillman / Refugio Volcanes EL 1045-1350m 18° 06’ W ”   ; 1 female, “ PARAGUAY: Canindeyu Mbaracayu Reserve 19-23-X1-2016 185m coll J. B. Heppner / Eunausibius   ” ( FSCA)   .

Distribution. Brazil, Bolivia and Paraguay.

Etymology. Name derived from Jatahy (Goiás, Brazil), the holotype locality.


Museum National d'Histoire Naturelle


Florida State Collection of Arthropods, The Museum of Entomology


Natural History Museum, Tripoli