Derallus paranensis Oliva, 1981

Rodriguez, Georgina, Torres, Patricia L. M. & Archangelsky, Miguel, 2020, Chaetotaxy and morphometry of the head capsule and head appendages of the genus Derallus Sharp (Coleoptera: Hydrophilidae), Zootaxa 4722 (5), pp. 423-442 : 429-432

Derallus paranensis Oliva, 1981

First instar larva. Chaetotaxy. Very similar to that of D. angustus except for the following differences. Head capsule ( Figs. 23–25 ). Frontale with seta FR5 longer than FR6; seta FR6 short and stout; seta FR10 longer; setae of gFR2 more evenly distributed. Parietale with PA1 slightly longer; pore-like sensillum PA 3 in a transverse line with seta PA2; seta PA12 closer to PA13 than to PA7; seta PA14 much longer; seta PA26 shorter than PA28. Antenna ( Fig. 26 ). A1 with inner sensory appendage bearing AN4 with short spine-like projections; seta AN10 longer, setae AN10-11 placed on membrane connecting with A3. Mandible ( Fig. 27 ). Seta MN1 slightly longer. Maxilla ( Figs. 28–29 ). Pore-like sensillum MX 3 visible in ventral view; seta MX 16 of first palpomere much longer; gMX with one long sensillum. Labium ( Figs. 24 , 30–31 ). Pore-like sensilla LA4 and LA7 closer to apical margins of mentum and prementum respectively.

Morphometry. Measurements and ratios shown in Table 1 .

Third instar larva. Chaetotaxy. Head capsule ( Figs. 32–34 ). Frontale without secondary sensilla; FR5 as long as FR6; seta FR10 much shorter than FR9. Ventral face of parietale with three pairs of short secondary setae arranged in a longitudinal line, one mesal to pore-like sensillum PA17, another mesal pore-like sensillum PA15 and the third pair mesal to seta PA18; setae PA7-8 much shorter, seta PA11 slightly shorter than PA14. Antenna ( Fig. 35 ). Without secondary sensilla, SE1 slightly shorter; seta AN11 proportionally longer. Mandible ( Fig. 36 ). With several (11–13) minute and very short secondary setae along outer margin between base of mandible and seta MN1; MN1 proportionally shorter. Maxilla ( Figs. 37–38 ). Stipes with eight short secondary setae along outer margin; MX 10-11 proportionally longer; MX 13, 23-24 proportionally longer. Labium ( Figs. 33 , 39–40 ). Mentum with three pairs of secondary setae; dorsally one pair short and stout setae on anterolateral corner, the other pair long, distal, close to midline, behind LA8; remaining pair ventral, short, subapical on outer margin; seta LA6 much shorter.

Morphometry. Measurements and ratios shown in Table 1 .

Figures

FIGURES 23–24. Derallus paranensis, head capsule, first instar larva. (23) dorsal view; (24) ventral view. Scale bar: 0.1 mm.

FIGURES 25–29. Derallus paranensis, first instar larva. (25) clypeolabrum, dorsal view; (26) left antenna, dorsal view; (27) left mandible, dorsal view; (28) left maxilla, dorsal view; (29) right maxilla, ventral view. Scale bars: 0.05 mm.

FIGURES 30–31. Derallus paranensis, first instar larva. (30) labium, dorsal view; (31) labium, ventral view. Scale bar: 0.05 mm.

FIGURES 32–33. Derallus paranensis, head capsule, third instar larva. (32) dorsal view; (33) ventral view. Scale bar: 0.1 mm.

FIGURES 34–38. Derallus angustus, third instar larva. (34) clypeolabrum, dorsal view; (35) left antenna, dorsal view; (36) left mandible, dorsal view; (37) left maxilla, dorsal view; (38) right maxilla, ventral view. Scale bars: 0.05 mm.

FIGURES 39–40. Derallus paranensis, third instar larva. (39) labium, dorsal view; (40) labium, ventral view. Scale bar: 0.05 mm.