Corydalus ignotus Contreras-Ramos, 1998

Azevêdo, Carlos Augusto Silva De & Hamada, Neusa, 2007, Description of the larvae of Corydalus batesii MacLachlan and C. ignotus Contreras-Ramos (Megaloptera: Corydalidae) with notes on life history and behavior, Zootaxa 1631 (1), pp. 33-45 : 38-43

Last-instar larval description of Corydalus ignotus Contreras-Ramos, 1998

Dorsal and ventral habitus ( Figs. 4A–B ).

Diagnosis. The epistomal suture of this species is reddish brown to black, while areas next to the stemmata, frontal suture, frontal sclerite, and coronal suture are reddish brown. Lateral areas of the coronal and occipital suture are dark brown to reddish brown and the apex of the submental projection is acute, extending beyond the anterior edge of the mental plate. Its mandibles have a wide basal tooth that is almost fused to the 2 nd tooth. Abdominal tergites have thin, elongate, pale-brown microsetae, distributed sparsely among the pale-brown, clavate and tubular macrosetae.

Larval description. Total length of larva: mean = 4.8 ± 0.27, n = 79.

Head. Dorsally with posterior area pale brown color, with reddish pattern similar to the pronotum ( Fig. 5B ). Pleurostomal region dark brown to black; epistomal suture reddish brown to black; areas next to stemmata, frontal suture, frontal sclerite, and coronal suture reddish brown ( Fig. 5B ). Genal carina dark, stemmata surrounded dorsally by a pale-brown stripe. Post-ocular region and occipital carina with pale-brown to reddish color pattern; post-ocular carina dark brown ( Fig. 5B ). Lateral area of coronal and occipital suture dark brown to red ( Fig. 5B ). Presence of long setae on the lateral area of the post-ocular carina. Occiput region with four pale-brown stripes, alternated with dark-brown areas ( Fig. 5B ). Labrum wide, dark brown. Clypeus 2.5 times wider than long, pale brown to dark, with dark lateral spots and three pale longitudinal stripes. Ventral region dark-brown to reddish color. Gular plate with reddish-brown lateral area; carina and occipital sutures dark brown to red. Next to the submental projection are small, anteriorly bent setae. Submental projection with acute apex, extending beyond the anterior edge of the mental plate ( Fig. 6B ). Mandible pale brown with central area dark brown to reddish; borders and lateral areas of teeth dark; apical tooth longer and thinner than penultimate one, which is longer than the 3 rd tooth; basal tooth wide and almost fused to the 2 nd tooth ( Fig. 7A ). Maxilla dark reddish brown, with lateral setae similar to spine on the inner margin. Stipe of the maxilla pale brown to dark. Maxillary palp pale brown to dark reddish brown, surrounded by pale and dark setae. Labial palp pale brown to dark, with three segments.

Thorax. Pronotum dark brown to black; anteromedian area with pale spots ( Fig. 5B ) postero-median region and area adjacent to thoracic suture with color pattern similar to head, pale brown to red ( Fig. 5B ); lateral area dark brown, with short and long setae bent toward anterior region. Ventrally, with antero-median region pale brown to dark; triangular sternellum with short setae. Meso- and metathorax subequal in width and length. Thoracic sternite covered with tubular and clavate micro- and macrosetae, pale brown. Dorsally, with pattern similar to the pronotum, short setae on the lateral and antero-posterior areas; dark areas with long setae; claviform macrosetae. Legs pale brown to dark.

Abdomen. Dorsally, pale brown to dark. Ab 1-8 with lateral filaments and small number of filamentous setae on up to half of the filament. Spiracles located dorso-laterally in the anterior region of lateral abdominal filaments. Spiracles almost straight in the anterior region; posterior region more elevated than anterior ( Fig. 8B ). Tergites with thin, elongated, pale brown to dark microsetae, distributed sparsely among the pale-brown, clavate and tubular macrosetae ( Fig. 9B ). Sternites, with large number of dark microsetae and pale-brown macrosetae. Ab 1 sternum with one pair of long setae medially; two pairs of long setae on Ab 1-8 sternites; areas of Ab 1-7 without microsetae forming a V-shaped pattern medially ( Fig. 10B ); Ab 8 with two rounded areas without microsetae and two long filamentous setae. Ab 9-10 with median sclerotized plate pale brown to dark, in the other abdominal segments, this plate is absent. Macro- and microsetae present on base of abdominal filaments. Ab 1-7 with gill tufts, decreasing in size posteriorly, each side of gill tuft composed of three segments bearing gill filaments ( Fig. 3B ).

Material examined (all larvae are last instar). BRAZIL: Amazonas: Presidente Figueiredo County: Igarapé do Km 13 , Comunidade Marcos Freire , Highway AM 240, 1 L, 29.ii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé do ramal do Canoas-Ponte , Highway BR 174, 01°49’18’’S / 60°10’07’’W: 1 L, 10.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Hamada, N. & Pereira, D.L.V.; Igarapé da Onça , Recanto da Pantera, Highway AM 240, Km 20, 02°00’52’’S / 60°01’43’’W: 1 L, 11.ix.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Pereira, D.L.V.; Igarapé do ramal do Km 24 , Sr. José , Highway AM 240, 02°01’07’’S / 59°49’28’’W: 3 L, 12.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé II do ramal da Morena, Highway AM 240, 02°00’58’’S / 59°51’33’’W: 1 L, 14.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé do Mutum , ramal da Porteira, Highway AM 240, 02°02’15’’S / 59°54’53’’W: 1 L, 14.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé da Cachoeira de Iracema , Highway AM 240, Km 17, 01°59’10’’S / 60°03’44’’W: 4 L, 9.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé da Corredeira do Camarão (afluente), Highway BR 174, KM 110; 02°01’05’’S / 60°02’04’’W: 1 L, 10.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Rio Urubuí , Highway BR 174, Km 110; 02°01’05’’S / 60°02’04’’W: 2 L, 10.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé II do Km 60, Highway AM 240, 01°59’27’’S / 59°31’35’’W: 1 L, 13.x.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Bobot, T.E.; Pereira, D.L.V.; Igarapé I do ramal da Maroca, Highway AM 240, Km 17, 02°00’58’’S / 59°51’33’’W: 5 L, 11.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé II do ramal da Maroca, Highway AM 240, Km 17, 02°00’58’’S / 59°51’33’’W: 5 L, 11.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé I do ramal da Cachoeira do Boto , 02°07’06’’S / 59°19’17’’W: 5 L, 12.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé da Corredeira Pedra Furada , Highway AM 240, Km 57, 01°59’34’’S / 59°33’26’’W: 5 L, 13.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé do Balneário Água Viva , Highway AM 240, Km 12, 02°03’11’’S / 59°55’24’’W: 1 L, 15.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé da Vivenda Fênix , ramal do Rio Urubuí , 02°03’00’’S / 60°06’09’’W: 1 L, 16.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V. Manaus: Reserva Ducke : Highway AM 010, Km 26, 02º55’S / 59º59`W; Igarapé Barro Branco ; 1 L, 30.i.2001, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Acará-31 , 1 L, 31.i.2002; Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Barro Branco ; 2 L, 18.ii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Barro Branco ; 1 L, 9.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Bolívia-31 ; 1 L, 16.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Bolívia-13 ; 3 L, 18.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Bolívia-12 ; 2 L, 19.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Bolívia-21 ; 1 L, 19.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Ipiranga-14 ; 7 L, 24.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Ipiranga-21 ; 2 L, 26.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Ipiranga-12 ; 1 L, 27.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Ipiranga-11 ; 1 L, 28.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Acará-32 ; 2 L, 5.iv.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Uberê-21 ; 2 L, 10.v.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Uberê-11 ; 1 L, 13.v.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Acará-12 ; 1 L, 5.vi.2002; Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Tinga-12 ; 1 L, 7.v.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Tinga-14 , 1 L, 11.vi.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Uberê-13 ; 1 L, 12.v.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Tinga-32 ; 1 L, 13.vi.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Tinga ; 1 L, 13.vi.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Acará-23 ; 1 L, 1.vi.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Barro Branco ; 2 L, 6.viii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Bolívia-16 ; 2 L, 7.viii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Barro Branco ; 2 L, 8.viii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Acará-Lages ; 2 L, 9.viii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Bolívia-14 ; 1 L, 14.viii.2002, Azevêdo, C.A.S. & Pes, A.M.O.; Igarapé Acará I ; 1 L, 20.xi.2002, Azevêdo, C.A.S. & Pes, A.M.O .

Remarks. Corydalus ignotus larva can be distinguished from the other two species of Corydalus , with known larvae by the anteromedial region of its head being dark brown to reddish, while C. nubilus larvae have two light brown dorsal spots centrally and C. batesii has a pair of pale, wide, horizontal stripes anteriorly. Corydalus ignotus has mandibles with three apical teeth distinct and two basal teeth fused, similar to that of C. batesii , while in C. nubilus the basal teeth are not fused. Corydalus ignotus has the submental projection acute, similar to C. nubilus , while in C. batesii this projection is blunt. Abdominal tergites of C. ignotus have thin, elongate, pale-brown to dark microsetae, sparsely distributed among the pale-brown macrosetae, while in C. nubilus the microsetae are also elongate and thin, but they are darker and densely distributed. Conversely, C. batesii has subtriangular microsetae and pale-brown to dark macrosetae that are either claviform, tubular, or star-shaped.

Figures

FIGURE 3. Larval dorsal (A) and ventral (B) habitus of Corydalus batesii.

FIGURE 4. Larval dorsal (A) and ventral (B) habitus of Corydalus ignotus

FIGURE 5. Dorsal view of head and pronotum of the larvae: A. Corydalus batesii, B. Corydalus ignotus, C. Corydalus nubilus.

FIGURE 6. Ventral view of cardo, gular plate and lateral projection of mental plate of the larvae: A. Corydalus batesii, B. Corydalus ignotus, C. Corydalus nubilus.

FIGURE 7. Dorsal view of mandible, clypeus and labrum of the larvae: A. Corydalus batesii, B. Corydalus ignotus, C. Corydalus nubilus.

FIGURE 8. Dorsal view of spiracle of the 1st abdominal segment of the larvae: A. Corydalus batesii, B. Corydalus ignotus, C. Corydalus nubilus.

FIGURE 9. Dorsal view of the macro and microsetae of the 5th abdominal segment in larvae: A. Corydalus batesii, B. Corydalus ignotus, C. Corydalus nubilus.

FIGURE 10. Ventral view of the 5th abdominal segment with V-shaped pattern in larvae: A. Corydalus batesii, B. Corydalus ignotus, C. Corydalus nubilus.