Casignetus spixi (Perty, 1830)

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 : 504-505

Casignetus spixi (Perty, 1830)

Larvae description ( Figs. 74–86 ). Body. Larvae ♀, length 28.27 mm. Head. Cephalic capsule ( Fig. 11 ) measuring 5.8 mm from apex of mandibles until posterior margin, 5 mm of wide; 1 lateroepicranial setae in each side. Each side of frons with 2 externofrontal setae. Base of clypeus ( Figs. 14 , 74 ) measuring about 2.5 times the length. Posterolabral seta located on left side. Corypha ( Figs. 17 , 75 ) with 6 setae, haptomerum with 3 sensillae, acroparia with 3 setae, achantoparia with 7 setae in each side; chaetoparia right with 54 setae, chaetoparia left with 27 setae, protophoba with 2 setae and 11 sensillae. Uncus of galea ( Figs. 36 , 76–77 ) circled dorsally by 7 long setae; galea with a row of 10 long setae in the inner ventral margin. Lacinia with 30 setae on inner lateral margin. Hypopharynx ( Figs. 35 , 82–83 ) with 63 setae. Labium ( Figs. 34 , 84 ) with 3 anterior setae on each side. Legs. Posterior face of mesocoxa ( Figs. 41 , 85 ) weakly excavated. Pars stridens ( Figs. 41 , 85 ) with 51 teeth; proximal teeth 3–4 in pairs; proximal extremity presenting a grainy area. Plectrum ( Figs. 44 , 86 ) comprising 50 teeth. Posterodistal extremity of metatrochanter forming an angle of approximately 45°. Abdomen. Raster ( Fig. 47 ) comprising of 281 short setae. Anal lobes ( Fig. 50 ) with a glabrous discal area, and 6 short setae on anterior margin of each abdominal lobe.

Material examined. 2 larvae (1♂ and 1♀, Nova Friburgo , Rio de Janeiro, Brazil—CERPE) .

Remarks. Casignetus spixi is the most common species of Casignetus found in the Brazilian entomological collections, and with a wider geographic distribution range, occurring from Rio de Janeiro state in Brazil to Missiones, Argentina. The Mizunuma & Nagai (1994) locality record from Mato Grosso do Sul, western Brazil, is considered by us as coming from mislabeled specimens since no Lucanidae have been found in that region. Furthermore, the orographic aspects of this state do not correspond to those required for the development of Casignetus species, or any other Brazilian Atlantic Forest species requiring high elevations and relative humidity ( Grossi 2018).

Figures

FIGURES 74–86. Casignetus spixi larvae. 74, Labrum 75, epipharynx 76–77, left maxilla (dorsal, ventral); 78–79, right mandible (ventral, dorsal); 80–81, left mandible (dorsal, ventral); 82–83, hypopharynx (dorsal, lateral); 84, labium; 85, left mesothoracic leg (external); 86, left metathoracic leg (internal). Scale bars = 1 mm. Photographs: D. Basílio.

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.