Dilychnia succensa, (OLIVIER, 1907), 2020

DILYCHNIA SUCCENSA ( OLIVIER, 1907) View in CoL COMB. NOV.

( FIGS 4, 10, 28–32)

Photinus succensus Olivier, 1907: 38 View in CoL (desc.); Blackwelder, 1945: 359 (cat.); McDermott, 1966: 46 (cat.).

Photinus atritarsis Pic, 1931: 108 (desc.); Blackwelder, 1945: 357 (cat.); McDermott, 1966: 46 (cat.; syn.).

Photinus grandis Pic, 1931:108 View in CoL ; McDermott, 1966: 39 (cat.), syn. nov.

Type material: Holotype examined, male ( MNHN) ( Fig. 28A). Labels: Jatahy (Goyaz) [green label]; Photinus succensus Ern. Oliv. [light brown label] ( Fig. 28B). Note that both males of the holotypes of P. atritarsis and P. grandis described by Pic ( MNHN) were examined.

Diagnosis: Males with antennomere III as long as scape ( Fig. 10G); sterna VI and VII with subrectangular light organs, occupying the median region of the sternum, almost reaching the lateral margin ( Fig. 29D); sternum VIII with posterior margin mucronate, as projected, obtuse ( Fig. 30A–D). Hypomera trapezoidal and median region projected ( Fig. 30E). Scutellum triangular, acute posteriad ( Fig. 29A). Elytron slightly convex with lateral margin subparallel ( Fig. 31A–C). Hind wing well developed, posterior margin sinuose, 2× longer than wide. Subcostal almost reaching anterior margin; CuA2 absent, costal row with setae inconspicuous; MP-Cu present; RP + MP 1 + 2 three-quarters of r4 length, almost reaching distal margin, J as long as RP + MP 1 + 2 ( Fig. 31D); pro-, meso- and metafemur subequal in width. Tarsomere I with lateral margin straight and tarsomere I of pro- and mesoleg 1.5× longer than II, tarsomere I of metaleg 2× longer than II; pro- and mesotarsomere with apex indented; II 1.5× longer than III; III subrectangular; claws simple ( Fig. 32).

long as one-quarter of height of sternum ( Fig. 4E); pygidium with lateral margin rounded and posterior margin with parasagittal indentation and median region truncate ( Fig. 4D); paramere with rounded projection and phallobase symmetrical with median region of posterior margin emarginate ( Fig. 4G–I).

Colour pattern: Frons light brown ( Fig. 10A, F); antenna dark brown ( Fig. 10G); mouthparts light brown ( Fig. 10A); pronotum with anterior margin orange and region over the head and posterior margin brown ( Fig. 30A, C, D); scutellum light brown ( Fig. 29A); elytra light brown ( Fig. 31A–C); pro-, meso- and metalegs with femur and tibia orange and tarsus dark brown ( Fig. 32); sterna II and III brown, sternum IV dark brown, sterna V – VIII and pygidium black, and sternum VIII light brown ( Figs 4A–E, 29C).

Head: Antenna slightly serrate, covered with short setae ( Fig. 10G). Labrum rounded anteriad, as long as wide ( Fig. 10A, F). Maxilla with palpi four-segmented: I small, triangular and thin in comparison to II; II 2× longer than III, cylindrical; III rectangular with rounded margins; and IV fusiform medially, 1.5× longer than II, narrowing towards apex ( Fig. 10A–F). Labium with palpi three-segmented: I cube shaped; II 2.5× longer than I, slightly enlarged towards apex; and III securiform, as long as II ( Fig. 10A–F).

Thorax: Pronotum trapezoidal, one-third wider than long, with anterior margin having few punctuations, and region over the head convex, anterior and lateral margin slightly concave, posterior margin with median region straight and posterior angles Abdomen: Sterna lateral margin rounded, posterior angles acute ( Fig. 4A–C); sterna VI and VII with light organ complete ( Fig. 29D); sternum VIII slightly wider than long, lateral margin rounded ( Fig. 4E); pygidium slightly wider than long, posterior margin with two parasagittal indentation, median region sinuose and posterior angles projected beyond median region ( Fig. 4D); and sternum IX subtriangular with posterior margin rounded ( Fig. 4F).

Aedeagus: Phallobase posterior margin slightly emarginate; paramere acute apically with lateral margin sinuose; phallus extending to half of phallobase length ( Fig. 4G–I).

Female: Pronotum slightly wider than long; sternum IV with posterior margin black; sternum VI median region with rectangular light organ with angles rounded, width slightly smaller than half of width of sternum; sternum VII median region with light organ with posterior margin sinuous; sternum VIII light brown, with lateral margins sinuose, posterior one-third straight, converging posteriad, and posterior margin with median region indented; pygidium posterior margin with posterior angles straight and median region rounded.

Remarks: Dilychnia succensa can be distinguished from others by its colour pattern, its dark orange– brownish pronotum and elytra ( Figs 29A, 30, 31A–C), serrate and black antennomeres III –X ( Fig. 10G), dark brown sterna IV– VIII ( Figs 4A–C, 29B), the pygidium with projected posterior angles ( Fig. 4D) and the male aedeagus with an emarginate phallobase ( Fig. 4G).

This firefly is active from twilight and throughout the first hours after nightfall, constantly flashing during this period. The flashing pattern is composed of three to four light-orange flashes.

Examination of the holotypes of P. atritarsis and P. grandis allow us to synonymize both species described by Pic (1931) with P. succensus , based on colour pattern, serrate antenna, subrectangular light organ and mucronate sternum VIII, in addition to the results from our phylogeny. We transfer this species here to Dilychnia , as D. succensa , following our phylogenetic study.

Material examined: BOLIVIA: BuenaVista: Pcia. Iehilo, 1 male, I.1950, A.Martinez ( MZSP); Santa Cruz: Florida , Refugio Los Volcanes , 18°06 ′ 3 ″ S, 63°26.0 ″ W, 1050–1150 m, 2 male, 10–14.XII.2011, L. Sekerka, Luz ( NHMUK) . BRAZIL: Distrito Federal: Planaltina, 15°35 ″ S, 47°42 ″ W, 1 male, 23. III .1973, V . O. Becker (EMBRAPA); Goiás: Formosa , 800 m, 2 female, 1 male ,

21.X.1976, V. O. Becker (EMBRAPA), Viannopolis , 1 male , XII.1931, R. Spitz ( MZSP); Minas Gerais: Conceição do Ibitipoca , 1 male , 30.XII.2002, A. H. Leal ( DZRJ), Jaboticatubas, Córrego das Pedras, Parque Nacional Serra do Cipó , 1 male , 12.XII.2011, D. Takiya & A. Santos, Luz ( DZRJ), Marliéria, Parque Estadual do Rio Doce, Timóteo , 2 male , 08–15.XII.1979, M. A. Vulcano & F. S. Pereira ( UFMG), Ponte Nova , 1 female , 25. II .1962 , J. Bechyné ( MZSP), Pouso Alegre , 1 male, 24–25. VI .1965 , Vulcano-Pereira ( MZSP), 1 male, XII.1953, P. Pereira ( MZSP), Serra do Caraça , 1 male , 27.XI–05.XII.1972, Expedição Museu de Zoologia ( MZSP), Serra do Caraça , 1 male , XII.1974, M. R. Monné ( MNRJ), Viçosa , 1 male , 02.I.2017, L. Silveira, Busca ativa ( DZRJ), 1 female, 4 male , 03.XII.1958, E. Amante ( MZSP), Viçosa, Cafezal próximo à UFV, 1