Corydalus batesii MacLachlan, 1868

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 : 36-38

Last-instar larval description of Corydalus batesii MacLachlan, 1868

Dorsal and ventral habitus ( Figs. 3A–B ).

Diagnosis. Larvae of this species have the region between the stemmata, genal carina and the median region of the frontal suture with wide, pale-yellow bands. The apex of the submental projection is blunt and does not pass beyond the anterior edge of the mental plate. The mandible has the basal-most tooth wide, truncate and partially fused to the 2 nd tooth. Abdominal tergites have black, subtriangular microsetae and pale-brown to dark macrosetae that are either claviform, tubular, or star-shaped.

Larval description. Total length: mean = 7.3 ± 0.70 mm, n = 34.

Head. Posterior region with color pattern similar to the thorax ( Fig. 5A ). Pleurostomal region and epistomal suture dark brown to black; front area of the sclerite pale brown to dark reddish; posterior median region with clear spots ( Fig. 5A ). Region between the stemmata, genal carina and median region of the frontal suture with wide, pale-yellow bands ( Fig. 5A ). Long setae present around the stemmata. Region around coronal suture brown to dark reddish ( Fig. 5A ). Occipital carina dark reddish brown to almost black. Occiput region with four pale-brown bands alternating with dark brown ( Fig. 5A ). Antenna with five segments, dark brown to black in color. Labrum longer than wide, narrowing at the anterior region, with dark spots on the lateral area. Clypeus 2.5 times wider than long, with two black lateral spots near the epistomal suture, with three longitudinal, thin, clear, stripes ( Fig. 5A ). Ventral region pale brown to dark reddish color, with pale-yellow pattern; areas next to the cardo, gular plate and submental projection dark brown ( Fig. 6A ); small setae bent toward the anterior region of the head. Gular plate with three pairs of lateral setae. Post-ocular carina with rows of short setae; lateral area of gular plate with pale-brown pattern similar to the prothorax ( Fig. 6A ). Anterior region of the gular plate with one pair of pale-brown spots, and apex of the submental projection approximately blunt, short and relatively wide, not passing beyond the anterior edge of the mental plate ( Fig. 6A ). Mandible with five teeth, dark reddish brown, to black; lateral areas of the mandible dark; apical tooth twice length of penultimate one, which is larger than the 3 rd tooth; basal-most tooth wide, truncate and partially fused to the 2 nd tooth ( Fig. 7A ). Maxilla with lateral border pale brown to dark. Long setae resembling thorns on the inner margin of the maxilla. Maxillary palp with four segments; galea with two segments; labium pale brown to dark, usually surrounded by pale setae. Glossa pale brown to dark; labial palp three-segmented, pale brown to dark.

Thorax. Pronotum pale brown to dark, almost black, pattern similar to that of head; lateral area pale brown to dark reddish, dorsally with small setae sparsely distributed and bent toward the anterior region. Antero-median and medial area of prothorax paler than laterally ( Fig. 5A ). Ventrally, prothorax with anteromedian area pale brown, with short setae bent toward anterior end; lateral margin dark brown to almost black; sternellum triangular with central projection dark brown, covered with short setae. Pleural region of prothorax with short microsetae, dark brown to black. Meso- and metathorax subequal in width and length, with pattern similar to the pronotum. Both segments have a row of long, thin setae on the margins and dark areas on the anterior region with clavate microsetae which are dark brown to black. Ventrally, median region with microsetae. Legs have color pattern with alternate pale and dark brown sections.

Abdomen. Lateral filaments with long setae, directed dorsally; spiracles round, with straight anterior margin and depressed medially ( Fig. 8A ). Ventrally, base of abdominal sternites one through seven (Ab 1-7) with tufts of lateral gills decreasing in size; each gill tuft composed of three segments bearing branchial filaments ( Fig. 3B ). Dorsally, tergites with large number of black, subtriangular microsetae, pale-brown and dark macrosetae with shapes varying from star-shaped to claviform and tubular ( Fig. 9A ). Ventrally, sternites covered with microsetae and a small number of clavate and tubular macrosetae; Ab 1 with one pair of long setae medially; Ab 2-8 with two pairs of long setae; Ab 2-7 medially with area lacking microsetae in a V-shaped pattern ( Fig. 10A ); Ab 8 medially with two oval areas without microsetae. Ab 9-10 with median sclerotized plate pale brown to dark; in the other abdominal segments, this plate is absent.

Remarks. The larvae of C. batesii can be distinguished from those of C. nubilus and C. ignotus by having a pale, wide, horizontal stripe between the stemmata, genal carina and median region of the frontal suture which is absent in the latter two species. Corydalus batesii have mandibles with three apical teeth distinct and two basal teeth fused, similar to C. ignotus , while in C. nubilus the basal teeth are not fused. Corydalus batesii submental projection is blunt while in C. nubilus and C. ignotus this projection is acute. Abdominal tergites of C. batesii have subtriangular microsetae and macrosetae that are claviform, tubular, or star-shaped, while in C. nubilus and C. ignotus the microsetae are thinner and elongated and star-shaped macrosetae are lacking.

Material examined (all larvae are last instar). BRAZIL: Amazonas: Presidente Figueiredo County; Igarapé do ramal do Castanhal , 03°01’45”S / 60°08’33”W: 3 L, 9.ix.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: 4 L, 22.xi.2001, Azevêdo, C.A.S.; Pes, A.M.O.; Hamada, N. & Nessimian, J.L.; 2 L, 12- 13.xii.2001, Azevêdo, C.A.S. & Pes, A.M.O.; 2 L, 11.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; 1 L, 16.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé do Sr. José , ramal do Km 24, Highway AM 240, 02°01’07’’S / 59°49’28’’W: 2 L, 12.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé da SUFRAMA , Highway BR 174, Km 97, 02°08’07’’S / 59°59’46’’W: 1 L, 13.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé II do ramal da Morena, Highway AM 240, 02°01’12’’S / 59°26’19’’W: 1 L, 19.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé I do ramal da Morena, Highway AM 240, 02°04’15’’S / 59°20’52’’W: 1 L, 19.ix.2002, Azevêdo, C.A.S.; Pes, A.M.O. & 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 afluente da Corredeira do Camarão , (Afluente do Rio Urubu ), 02°01’05’’S / 60°02’02’’W: 1 L, 10.x.2002, Azevêdo, C.A.S.; Pes, A.M.O. & Pereira, D.L.V.; Igarapé do Sítio São Francisco , Km 30, Highway AM 240, 02°02’30’’S / 59°46’06’’W: 4 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°05’58’’W: 1 L, 16.x.2002, Azevêdo, C.A.S.; Pes, A.M.O.; Bobot, T.E. & Pereira, D.L.V.; Igarapé da Corredeira do Portal dos Anjos , ramal do Rio Urubuí , 02°03’38’’S / 60°05’58’’W: 2 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, 2º55’S / 59º59´W; Igarapé Acará-Lages , 1 L, 23.i.2002, Azevêdo, C.A.S. & Pes, A.O.; Igarapé Bolívia-31, 1 L, 17.iv.2002, Azevêdo, C.A.S. & Pes, A.O.; Igarapé Bolívia near camp, 1 L, 23.iv.2002, Azevêdo, C.A.S. & Pes, A.O.; Igarapé Acará-I , 1 L, 20.xi.2002, Azevêdo, C.A.S. & Pes, A.O.; Igarapé Cabeça Branca , Highway BR 174, Km 24, 1 L, Azevêdo, C.A.S. & Pes, A.M.O .

Figures

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

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.