Eunausibius elongatus (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 : 30-33

Eunausibius elongatus (Grouvelle)

( Fig. 103–119 )

Nausibius elongatus Grouvelle 1896: 192 (type examined)

Eunausibius elongatus (Grouvelle) ; Grouvelle 1913: 314.

Diagnosis. Eunausibius elongatus is readily distinguished from the other two congeneric species ( E. tenebrioides and E. jatahyensis ) by the conspicuous pubescence on the dorsal side including setae between the eye facets.

Description. Known to the current author from the holotype and 16 specimens found amongst Silvaninae sent on loan by Dr. M. C. Thomas. Measurements and ratios are based on the holotype and 9 of the additional specimens. Length 3.00– 5.43 mm, elongate, ratio of total length to elytral breadth, 37.0–43.5:10.0, general appearance sub-cylindrical, very dark brown (almost black), dorsum pubescent, setae long, dark golden.

Head. Generally transverse, ratio of breadth to length, 10.0–12.2:10.0, moderately raised medially on anterior half, slightly depressed above antennal insertions; punctures small on raised region, larger elsewhere (not confluent); eyes prominent, separated across head by 4.8–7.6× breadth of eye in dorsal view, about half as long as head, obvious setae present between eye facets; antenna usually with a gradually developed 4-segmented club but this may be somewhat abruptly developed, the comparative length of antennomere 7 is also a little variable ( Fig. 106 , 111, 113, 116).

Pronotum. Elongate, ratio of length to breadth, 11.4–12.8:10.0; lateral margins usually more or less smooth ( Fig. 111, 112, 115) although holotype has about 4 very weak, ill-defined irregular prominences in addition to anterior and posterior angles ( Fig. 103 ); anterior angles poorly developed; posterior angles dorsally slightly bent upwards; lateral rims very fine, not produced beneath anterior angles; puncturation dense but not confluent or rugose, punctures with conspicuous setae ( Fig. 103 ) median longitudinal impunctate area present (limits of area shown by dots on Figures).

Elytra. Sub-cylindrical, elongate, length to breadth ratio, 21.0–26.2:10.0; 9 rows of punctures forming striae on each elytron, including 2 on lateral declivities, interstriae with single row of fine punctures; all setae long and sub-decumbent, those associated with strial punctures, slightly longer and less decumbent than those born on interstrial punctures ( Fig. 105 ); apical fifth with ill-defined fine line along sutural side of first punctate stria ( Fig. 103 ).

First abdominal ventrite. Femoral line may be very strongly produced, reaching apical sixth of ventrite ( Fig. 104 ), however it is of variable development, occasionally not developed but forms margin of metacoxal cavity.

Legs, male. Metafemora with small tooth on proximal side ( Fig. 103 ), metatibiae with a few ill-defined oblique striae.

Male genitalia. Seven male specimens were dissected and it was found that, as with external characters, the male genitalia are somewhat variable in this species. The parameres vary in length and breadth, the apex of the median strut varies in shape, sometimes broader and more rounded with its margin thicker, the length of the rods varies, as does the shape of sternites 8 and 9. This range of form of these structures, as observed in the seven specimens, is shown in the illustrations for two of them ( Fig. 108–110 , 117–119). More details regarding these and other parts of the genitalia are as follows: Area towards ostium with about 18–19 rods on each side; median 113) Antenna of 112 enlarged. 114) Pronotum of female. 115) Habitus, narrow male specimen. 117–119) Male genitalia and associated sclerites. 117) Genitalia of 115

(internal sac not included). 118) Paramere, enlarged. 119) Sternites 8–9. Scale lines for Figures 111–112 and 115 (114 also to same scale) = 2.0 mm., for Figures 117 and

119 = 0.2 mm.

lobe broad, lateral margins moderately curved to apex, apical margin straight or slightly emarginate with a few fine setae; internal sac with complex armature ( Fig. 109 ); parameres moderately long, sides almost parallel before being rounded to apex, a few (5–7) long setae towards apex, also a few shorter setae on basal half of outer margin.

Material examined. Holotype male from BRAZIL: “ S. Antonio da Barra Pr de Bahia Gounelle 11–12. 88 [printed] /

Type [printed] / sill antin orty femorah / Nausibius elongatus Grouv. [handwriting on squared paper] / HOLOTYPE [printed, red label] / N. elongatus ty Grouv. [Grouvelle’s handwriting, green label]” (dissected: MNHN, Paris).

Other material. (16 total) 16 specimens from PANAMA, BOLIVIA and PARAGUAY as follows: 1 male “Ancon, C. Z. 9 May ’73 Panama H. Stockwell / LIGHT TRAP / H. Stockwell Collection” (dissected, FSCA) .; 1 male (dissected), 1 sex indet. “ BOLIVIA: Santa Cruz 3.7m SSE Buena Vista. Hotel Flora & Fauna , 430 m 14–19-X-2000 coll. M. C. Thomas tropical transition forest” ( FSCA) ; 1 males (dissected), 1 female (genitalia exposed), 1 sex indet. (no abdomen) “ BOLIVIA: Santa Cruz 3.7m SSE Buena Vista, Hotel Flora & Fauna 5–15-XI-2001 17° 29. 949′ S; 63° 33, 152′ W, coll. M. C. Thomas & B. K. Dozier tropical transition forest” (dissected, FSCA) ; 1 male (dissected) “ BOLIVIA Santa Cruz Potrerillo de Guandá 16–22-XII-2004 coll.: E. Nearns. UV Trap. ” ( FSCA); 3 specimens, sex indet., “ BOLIVIA SANTA CRUZ Res, Privada Potrerillos de Guendá ; −17º 40.26 −63° 27.44; black light; 10–29 / XI / 2006; B. K. Dozier ( FSCA) ; 1 female “ BOLIVIA: Santa Cruz Amboro National Park Los Volcanes, c. 1000m S. 18° 06′: W 63° 36′ 20 / xii / 2004 / MV Light Sheet on stream beach Barclay M. V. L. & Mendel, H. BMNH (E) 2004-280” ( NHML) ; 1 male (dissected) “ BOLIVIA S. Cruz Dept. 20km N. Camiri 5,6, 10 December 2012 Wappes, Bonaso, Skillman / Road to Eyti 1250m 6–8 km E Hwy 9 19° 52′ S 63° 29W ” ( FSCA) ; 2 females “ PARAGUAY: Cordillera Dept. Caacupé Campamento Jack Morment ; UV light trap S 25° 22.116′ WO 57° 07.917′ 11-14-XI-2016, J. E. Eger 812ft, permit #271 / 2016” ( FSCA) ; 1 male “ PARAGUAY: Cordillera Campamento Jack Morment , 11–14-XI-2016, J. E. Eger coll. / S 25° 22.116′ WO 57° 07.917′ 812ft, permit #271 / 2016 At MV & UV Light” ( FSCA) .

Figures

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.