Macraspis clavata (Olivier, 1789)

Medeiros, Rone A. F., Frazão, Carlos A. V., Grossi, Paschoal C. & Fuhrmann, Juares, 2019, Description of the third instar of Macraspis clavata (Olivier, 1789) (Coleoptera: Scarabaeidae: Rutelinae), Zootaxa 4638 (3), pp. 442-450 : 443-446

Macraspis clavata (Olivier, 1789) , last instar

( Figs. 1‒20 )

Description. Body ( Fig. 1 ) yellowish white; cranium, respiratory plates, and pretarsi dark brown; clypeus bicolored (apex dark brown, base yellow); labrum bicolored (apex dark brown, base yellow); mandibles black. Head ( Fig. 3 ): maximum width 7.8‒8.0 mm. Epicranial suture with coronal arm more than 0.33 times as long as greatest head width, and frontal arms V-shaped. Stemmata present. Cranium punctate, anterior half of frons sparsely punctate. Each side of epicranium with: a row of 4 dorsoepicranial setae (2 short, 1 medium, 1 long); 3‒4 posteroepicranial setae; 1‒2 anteroepicranial setae; about 5 externoepicranial setae; 2 posterofrontal setae (1 short, 1 long); 3 externo- frontal setae (2 medium, 1 long); 3 anterofrontal angle setae (1 short, 2 medium); 2 anterofrontal setae. Clypeus ( Fig. 3 ) subtrapezoidal, each side with: 1 anteroclypeal seta and 2 externoclypeal setae. Labrum ( Fig. 3 ) subovate, nearly symmetrical, apex widely curved, with a preapical transverse keel and 4 preapical rounded tubercles; each side with: 4 posteriolabral setae (2‒3 short, 1‒2 long), 2‒3 long laterolabral setae, 1 mediolabral seta; 2‒3 anterolabral setae. Epipharynx ( Fig. 9 ). Haptomerum moderately raised and with 14 spine-like setae, heli absent, zygum plate-like and with some sensilla, epizygum indistinct. Acroparia with 9‒10 short stout setae and 6 long setae. Left acanthoparia with 12 short setae, rigth acanthoparia with 9 short and 6 long setae. Plegmata absent. Gymnoparia narrow. Rigth chaetoparia with 17 thin short setae and 22 long setae, left chaetoparia with 19 thin short setae and 29 long setae, both sides with 45–51 stout setae. Dexiotorma elongate, slightly visible. Laeotorma elongate and with pternotorma wide and rounded. Haptolachus with a irregular shaped and sligthly sclerotized plate, sense cone large, each side with about 4 setae. Left mandible ( Figs. 10, 13 ): incisor with 3 teeth. Stridulatory area suboval and bearing 43 fine striae. Molar with 2 wide lobes. Acia indistinct. Brustia with 15 setae. Right mandible: ( Figs. 11–12 ) incisor with 2 teeth. Stridulatory area suboval and bearing 27‒28 striae. Molar with 3 lobes. Calx prominent, rectangular. Brustia with 6 setae. Maxilla: ( Figs. 6‒8 ) galea and lacinia fused (as a mala). Galea with 1 uncus, ventral surface with about 7 long setae a row of 7 spine-like setae. Lacinia with 1 reduced bare uncus and 31‒32 medium setae. Stipes with a row of 6 sharp stridulatory teeth and a distal truncate tooth. Palps with 4 palpomeres: II with a lateral setae; IV with 9 ventral sensilla. Labium: prementum with 8 medium setae. Palps with 2 palpomeres: I with a dorsal minute seta, II with a lateroapical sensillum. Apex of ligula with 10 long setae and 26‒28 spine-like setae. Hypopharynx: hypopharyngeal sclerome strongly asymmetrical, right side with raised tooth. Right lateral lobe with 4 long thin setae and 1 short thin seta, left lateral lobe with about 9 mixed long and short setae. Antenna: ( Figs. 4‒5 ) with 4 antennomeres: I 1.6 times smaller than II; IV with 8 dorsal sensorial spots and 8 ventral sensorial spots. Thorax: ( Figs. 1‒2 ) spiracle 0.70 mm wide, 0.93 mm high, about 1.2 times larger than abdominal spiracle I; respiratory plate C-shaped. Thoracical segment I (T1) with 3 lateral rows with 14 with medium-sized setae and 1 dorsal row with 15–18 medium-sized setae; T2‒T3 tergal anterior lobe of with 8‒15 setae (6‒8 thin, 7‒8 stout), tergal medial lobe with15‒18 setae (10‒11 thin, 4‒8 stout), tergal posterior lobe with 8‒10 thin setae, tergal lateral lobe without setae. Legs: (Figs. 14‒16) mesothoracic legs longer than prothoracic legs and shorter than metathoracic legs. Prothoracic legs: coxae with 40 setae (8 short, 14 medium, 18 long), trochanter with about 26 setae (5 short, 14 medium, 7 long), femur with 46 (4 short, 13 medium, 29 long), tibiotarsus with 48 setae (about 4 short, 20 medium, 24 medium). Mesothoracic legs: coxae with 52 setae (8 short, 18 medium, 26 long), trochanter with about 22 setae (10 medium, 12 long), femur 46 setae (4 short, 12 medium, 30 long), tibiotarsus with 52 setae (4 short, 20 medium, 28 long). Metathoracic legs: coxae with 52 setae (25 short, 15 medium, 12 long), trochanter with about 30 setae (18 medium, 12 long setae), femur with 45 setae (6 short, 14 medium, 25 long), tibiotarsus with 45 setae (20 medium, 25 long). Propretarsus and mesopretarsus ( Figs. 18‒20 ) with acute apex and bearing 2 lateral setae; propretarsus somewhat straight; mesopretarsus slightly sigmoideal; metapretarsus reduced and with 2 small setae. Abdomen: ( Figs. 1‒2 ) spiracles I‒VIII similar to each other, 0.59‒0.61 mm long in anteroposterior axis and 0.77‒0.80 mm long in dorsoventral axis. Abdominal segment I (A1) with tergal anterior lobe with 21 thin setae, tergal medium lobe with 68 setae (58 thin, 10 stout), tergal posterior lobe with 136 setae (124 thin, 12 stout); A2‒A6 with tergal anterior lobe with 72‒165 setae (68‒157 thin, 4‒8 stout), tergal medium lobe with 60‒130 setae (58‒112 thin, 2‒18 stout), tergal posterior lobe with 135‒156 setae (127‒146 thin, 8‒18 stout); A7 with tergal anterior lobe with 84 setae (72 thin, 12 stout); tergal medium lobe with 22 steae (20 thin, 2 stout); tergal posterior lobe with 8 setae (4 thin, 4 stout). A1‒A7 with tergal lateral lobe with 6‒12 setae (2‒10 thin, 1‒6 stout); spiracle lobe with 11‒14 setae (5‒9 thin, 4‒8 stout); pleural lobe with 6‒20 setae (2‒11 thin, 4‒9 stout). Raster: (Fig. 17) campus with 4 long, thin setae; each side of tegillar area with 94‒96 hamate setae of wich 20‒22 are preseptular; barbula indistict; palidia irregular, extended in anterior third of ventral anal lobe, each palidium bearing 14 stout pali; septula well defined and with irregular shape.

Natural history. The larvae of M. clavata are saproxylophagous and were found in rotten trunks, and can be found in association with pupae and teneral adults during the summer in its distribution region (December to February). Adults are usually active from May to August. This species occurs in southeastern and southern Brazil, in the States of Minas Gerais (MG), São Paulo, Rio de Janeiro (RJ), Paraná (PR), Santa Catarina, and Rio Grande do Sul ( Soula 1998 and new data). It was thought that this species was restricted to the Serra do Mar mountains (southeast Brazilian coast) above 1000 m (P.C. Grossi, personal observation), but it was also collected in Minas Gerais (southeastern interior) and Rio Grande do Sul (southern Brazil). Adults were collected feeding on flowers of Tibouchina spp. ( Melastomataceae ) (Tijucas do Sul, Paraná, in Atlantic Forest) (Fig. 21) and Inga striata Bentham (Mimosoidea) in Piraquara ; on flowers of Myrtacea (Guaratuba and Tijucas do Sul (Paraná); Nova Friburgo, Itatiaia and Rio de Janeiro (Rio de Janeiro); and Marliéria and Berizal (Minas Gerais )) (P.C. Grossi, personal observation).

Remarks. The third instar of Macraspis clavata is distinguished from the other known species of Macraspis larvae by the following combination of characters: labrum with 4 preapical rounded tubercles and 6 posterolabral setae on each side; acanthoparia with 10‒12 spine-like setae; maxillae with 6 stridulatory acute teeth; palidia ex- tended in the anterior third of ventral anal lobe. Macraspis clavata is quite similar to M. aterrima by the characteristics found in the frons, labrum, and maxilla. It is differentiated mainly by the number of dorsal and ventral antennae sensory spots, number of stridulatory teeth on maxilla, number of posterolabral setae, and number of epicranial setae (see couplet 7 of key). Regarding the other known Macraspis larvae, M. clavata is differentiated by the following characteristics: antennomere IV with 8 dorsal sensorial spots, haptomerum moderately raised and with 14 spine-like setae, brustia of left mandible with 15 setae; stridulatory area of right mandible with about 27‒28 striae; ventral surface of galea with a row of 7 spine-like setae. In addition to the key, the chaeotoxy of cranium, raster, and vental anal lobe can by used as suplementar data to identification ( Table 1 ).

Figures

FIGURES. 1‒5. Macraspis clavata third instar. 1, Habitus, lateral; 2, abdominal and thoracic spiracles, t, thoracic spiracle, I‒VIII, abdominal spiracle I‒VIII; 3, head, frontal. 4‒5, Antennomere III‒IV (dorsal, ventral). Scale bars = 3 mm for Fig. 1, 0.5 mm for Fig. 2, 1 cm for Fig. 3, 1 cm for Figs. 4‒5.

FIGURES 6‒9. Macraspis clavata third instar. 6, Right maxilla, dorsal; 7, stridulatory area of right maxilla; 8, right mala, inner; 9, epipharynx. Scale bars = 1 mm for Figs. 6, 9 and 0.5 mm for Figs. 7‒8.

FIGURES 10‒13. Macraspis clavata third instar. 10, 13, Left mandible (ventral, dorsal). 11‒12, right mandible (ventral, dorsal). Scale bars = 1 mm.

FIGURES 14‒20. Macraspis clavata third instar. 14‒16) Protibiotarsus‒pretarsus, mesotibiotarsus‒pretarsus, and metatibiotar- sus‒pretarsus; outer. 17, Venter of abdominal segment X. 18‒20, Propretarsus, mesopretarsus, and metapretarsus. Scale bars = 1 mm for Figs. 14‒17 and 0.5 mm for Figs. 18‒20.