Sennius transversesignatus (Fåhraeus, 1839), Fahraeus, 1839

Viana, Jéssica Herzog & Ribeiro-Costa, Cibele Stramare, 2013, Review of the largest species group of the New World seed beetle genus Sennius Bridwell (Coleoptera: Chrysomelidae), with host plant associations, Zootaxa 3736 (5), pp. 501-535 : 527-529

Sennius transversesignatus (Fåhraeus, 1839)

( Figs 83–91 )

Bruchus transversesignatus Fåhraeus, 1839: 26 (description, distribution); Gemminger & Harold 1873: 3231 (catalog, distribution); Costa Lima 1923: 182 (host); Zacher 1952: 472 (citation).

Acanthoscelides transversesignatus: Blackwelder 1946: 761 (catalog); Silva et. al. 1968: 375 (catalog, host, distribution); Udayagiri & Wadhi 1989: 66 (catalog).

Sennius transversesignatus: Kingsolver 1979: 412 ; Ribeiro-Costa & Reynaud 1998: 251 (citation).

Redescription. Dimension. BL: 1.9–2.7 mm; BW: 1.2–1.8 mm.

Integument color. Body black, maxillary and labial palpi dark brown; antennomeres 1–4 red-orange, 5–11 dark brown ( Figs 84, 85 ). Elytra black, each with red-orange rounded macula on posterior region reaching outer margin ( Fig. 83 ). Fore and mid leg red-orange; hind femur pale brown to black, hind tibiae and tarsus pale to dark brown ( Fig. 84 ).

Pubescence. Head with moderately dense white setae, except for small dense patch on post-ocular lobe; labrum with scattered golden setae ( Figs 84, 85 ). Pronotum with white setae laterally and on midline, remainder with scattered golden setae. Elytra with sparse golden setae and moderately dense white setae in 1st strial interval from basal to subapical region, on median region of 2nd strial interval and horizontal strip on submedian region covering red-orange macula ( Fig. 83 ). Pygidium with moderately dense white setae on basal region, denser laterally and on mid basal region, remainder with sparse golden setae. Ventral surface with moderately dense white setae, denser on mesepimerum base and on posterior region of metepisternum ( Fig. 84 ).

Head with frons slightly convex, frontal carina slightly evident or absent and ocular sinus slightly deep, less than half length of eye ( Fig. 85 ). Antennomeres 1 and 3 filiform, 2 and 4 moniliform, 5–10 wider than long, 11 globular but pointed apically. Disc of pronotum strongly sulcate at basal lobe. Elytra with denticle at base of 2nd strial ( Fig. 87 ). Hind femur on ventral margin with very prominent tooth (0.06–0.10 mm), not microserrate ( Fig. 88 ); hind tibia with lateroventral carina not reaching half its length ( Fig. 89 ).

Male genitalia. Median lobe strongly sclerotized, about 4.7 times longer than wide medially, apex strongly expanded. Ventral valve triangular with round apex and lateral margins concave. Internal sac with hinge sclerites; hinge sclerites long, strongly curved and thin; apical region with group of spicules near ventral valve; subapical region with two long and dense groups of short spicules; submedian region with four dense groups of long spicules grouped in pairs, two smaller groups near subapical region; latero-basal lobes of internal sac with dense and long spicules; basal region with sparse denticles near gonopore ( Fig. 90 ). Tegmen with lateral lobes separated by emargination about 0.8 times their length ( Fig. 91 ).

Material examined. Type (1): Bruchus transversesignatus Fåhraeus, 1839 . Syntype deposited in NHRS, with labels: “ Typus ” (Red) “In Semin. \ Cassiae Bras. [Brasiliae] \ Faldermann”(white). Note: In the original description, Fåhraeus (1839) did not mention how many specimens were studied. It was received from NHRS only one female specimen with type label which is here considered as syntype.

Non-type (62): TRI: Trinidad: St. Augustine: 1, II/1959, F. Bennet (CNCI); 2, 8–12 /I/1959 (USNM). BRA: Goiás: Catalão: 1, 28 /V/[19]66, S. Laroca (DZUP). Minas Gerais: Passos: 1, 8–14 /V/[19]63, Claudionor Elias (DZUP). Rio de Janeiro: Maricá : 1, Barra de Maricá , III– VI/1996, M. Pimentel, Senna australis (DZUP); 52, III– VI/[19]96, same collector (DZUP); 2, III/1987, L. R. C. Souza, Cassia australis (DZUP). São Paulo: Ibitinga: 1, 6 / IX/[19]88, E. C. Bergmann (DZUP). BOL: La Paz: Sud Yungas: 1, Puente Villa, 19–24/V/1989, J. E. Eger (DZUP).

Distribution. TRI, COL, BRA (Goias, Minas Gerais, Rio de Janeiro, São Paulo) and BOL (Sud Yungas, Santa Cruz).

Host plants. FABACEAE : Caesalpinioideae : Senna appendiculata (syn for S. australis ) Diagnosis. Sennius transversesignatus belongs to subgroup 1 of the S. abbreviatus group, along with seven species. It seems more similar to S. nappi , sharing the same pattern of the color integument, pubescence of elytra and male genitalia. Differences in color, pubescence and the structures of the male genitalia are discussed under "Diagnosis" of S. nappi and in Viana & Ribeiro-Costa (2013).

Figures

FIGURES 83 – 91. Sennius transversesignatus. 83, dorsal view; 84, lateral view; 85, head, frontal view; 86, pygidium; 87, base of elytra strial; 88, part of hind leg, internal view; 89, hind tibia, external view; 90, 91 male genitalia: 90, median lobe with hinge sclerites, others sclerites magnified and latero-basal lobes of internal sac; 91, tegmen.