Eunausibius jatahyensis Halstead, 2020

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

Eunausibius jatahyensis Halstead , new species

( Fig. 95–102 , 125 )

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 with 94). In addition, the sternites 8 and 9 differ (compare Fig. 96 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 ), apical segment small; ventral side of head with deep convergent antennal grooves as in the other two known species ( Fig. 101 ).

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 ); 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 ) 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 , but not long as in E. elongatus ( Fig. 104 ).

Male genitalia. ( Fig. 96–97 ) With median strut and internal sac similar to E. elongatus (see Fig. 108–109 ) 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 ); sternites 8 and 9 appearing moderately elongate, sternite 8 produced at sides ( Fig. 96 )

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 ; 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.

Figures

Figures 91–97. Eunausibius spp. 91–94) E. tenebrionoides (Grouvelle), male holotype. 91) Habitus, inset enlarged view of metafemoral spine. 92) First abdominal ventrite. 93–94) Genitalia and associated sternites. 93) Sternites 8–9. 94) Parameres and median lobe. 95–97) E. jatahyensis, new species, male holotype. 95) First abdominal ventrite. 96–97) Genitalia and associated sternites. 96) Sternites 8–9. 97) Parameres and median lobe. Scale lines for Figures 91, 92 and 95 = 2.0 mm, for Figures 93–97 (94 and 97 to same scale) = 0.5 mm.

Figures 98–102. Eunausibius jatahyensis, new species, types. Dots on pronotal disc show position of narrow, medial impunctate region. 98) Habitus, holotype male (Jatahy). 99) Habitus, paratype female (Jatahy). 100) Head, paratype female with smaller eyes dorsal view (Minas Gerais). 101) Head of holotype, ventral view to show eyes plus deep antennal grooves. 102) Elytron, small part enlarged (margin of suture on left) to show strial punctures, also very short, fine setae. Scale lines = 2.0 mm.

Figures 125–126. Color habitus photographs. 125) Eunausibius jatahyensis, new species. 126) Annomus bolivianus, new genus, new species.

Figures 103–110. Eunausibius elongatus (Grouvelle), male. 103) Habitus, dots on pronotal disc show position of narrow, medial impunctate region. An example of the pronotal puncturation is included. 104) First abdominal ventrite. 105) Elytron, small part enlarged (margin of suture on left) to show strial punctures with associated comparatively long, conspicuous setae, each above a strial puncture and similar setae in a line on interstriae. 106) Antenna, enlarged. 107) Pronotal punctures, an enlargement of some of those near the anterior margin to show their setae. 108–110) Genitalia and associated sternites. 108) Genitalia without internal sac. 109) Internal sac. 110) Sternites 8–9. Scale lines for Figure 103 (104 also to same scale) = 2.0 mm, for Figures 108–110 = 0.2 mm.