Casignetus humboldti (Gyllenhal, 1817)

Silva, Alessandra C. G. & Grossi, Paschoal C., 2019, Immature stages of the genus Casignetus MacLeay, 1819 (Coleoptera: Lucanidae: Lucaninae), Zootaxa 4568 (3), pp. 501-519 : 504

Casignetus humboldti (Gyllenhal, 1817)

Larvae description ( Figs. 64–73 ). Body. Larvae ♀, total length 21.98 mm. Head. Cephalic capsule ( Fig. 10 ) with 6.5 mm from apex of mandibles until posterior margin, 5 mm of wide; 1 lateroepicranial seta on each side. Each side of frons with 2 externofrontal setae. Base of clypeus ( Figs. 13 , 64 ) measuring about 2.5 times its length. Posterolabral seta located on left side. Corypha ( Figs. 16 , 65 ) with 9 setae, haptomerum with 8 sensillae, acroparia with 6 setae, achantoparia with 6 setae on each side, right chaetoparia with 48 setae, left chaetoparia with 39 setae, protophoba with 4 setae and 10 sensillae. Uncus of galea ( Figs. 33 , 70–71 ) surrounded dorsally by 6 long setae; galea with a row of 11 long setae on inner ventral margin. Lacinia with 32 setae on inner lateral margin. Hypopharynx ( Figs. 32 , 71 ) with 55 setae. Labium Figs. (31, 70) with 1 posterior seta on each side. Legs. Posterior face of mesocoxa ( Figs. 40 , 72 ) strongly excavated. Pars stridens ( Figs. 40 , 72 ) with 74 teeth; main row with 36 teeth; one adjacent row comprising 4 slightly apparent teeth on anteroproximal extremity, and 2 rows with 11 and 5 similar teeth, respectively, and a grainy area on posteroproximal extremity; distal extremity with about 18 teeth arranged irregularly. Plectrum ( Figs. 43 , 73 ) comprising 44 teeth. Posterodistal extremity of metatrochanter forming an angle of approximately 35°. Abdomen. Raster ( Fig. 46 ) comprising of 270 short setae. Anal lobes ( Fig. 49 ) glabrous.

Material examined. 6 larvae (1♂ e 5 ♀, Nova Friburgo , Rio de Janeiro, Brazil—CERPE) .

Remarks. Casignetus humboldti occurs in southeastern and southern regions of Brazil ( Lüderwaldt 1935; Weinreich 1963). However, among the material examined, and the collections studied by one of us (PCG), there were only specimens from southeastern region from the states of Espírito Santo, Rio de Janeiro, Minas Gerais, and São Paulo, and for the southern region there are only two known specimens ( Weinreich 1963). Considering this, it is necessary to confirm the records of the specimens from that region. Regarding the pupae of C. humboldti we have on hand, both male and female were nearing emergence, especially the female, whose thecae were damaged on many parts. For this reason, we do not present here full descriptions for this species. Additionally, most of the description of the genus was based on these pupae, and we consider not necessary to repeat it.

Figures

FIGURES 64–73. Casignetus humboldti larvae. 64, Labrum; 65, epipharynx; 66–67, right mandible (ventral, dorsal); 68–69, left mandible (dorsal, ventral); 70, maxillae and labium (ventral); 71, maxillae and hypopharynx (dorsal); 72, mesothoracic leg (external); 73, metathoracic leg (internal). Scale bars = 1 mm. Photographs: M. Cherman.

FIGURES 10–18. Head capsule (frontal), labrum and epipharynx of Casignetus larvae. 10, Casignetus humboldti; 11, C. spixi; 12, C. lindei; 13, labrum of C. humboldti; 14, labrum of C. spixi; 15, labrum of C. lindei; 16, epipharynx of C. humboldti; 17, epipharynx of C. spixi; 18, epipharynx of C. lindei. Scale bars = 1 mm.

FIGURES 31–39. Mouthparts of Casignetus larvae. 31–33, Casignetus humboldti labium, hypopharynx, and left maxilla (dorsal), respectively; 34–36, C. spixi labium, hypopharynx, and left maxilla (dorsal), respectively; 37–39, C. lindei labium, hypopharynx, and left maxilla (dorsal), respectively. Scale bars = 1 mm.

FIGURES 40–51. FIGURES 40–45. Stridulatory organs Casignetus larvae. 40, Pars stridens of C. humboldti; 41, pars stridens of C. spixi; 42, pars stridens of C. lindei; 43, plectrum of C. humboldti; 44, plectrum of C. spixi; 45, plectrum of C. lindei. Scale bars = 1 mm. FIGURES 46–51. Last abdominal segment of Casignetus larvae. 46, Raster of C. humboldti; 47, raster of C. spixi; 48, raster of C. lindei; 49, anal lobes (posterior) of C. humboldti; 50, anal lobes (posterior) of C. spixi; 51, anal lobes (posterior) of C. lindei (dilated anal region due to the presence of excrement at death). Scale bars = 1 mm.