Phileurus truncatus (Palisot de Beauvois, 1806)

Arguez, Katherine M., Moore, Matthew R. & Branham, Marc A., 2017, Description of the larva and pupa of Phileurus truncatus (Palisot de Beauvois, 1806) (Coleoptera: Scarabaeidae: Dynastinae: Phileurini) with a key to described third instars of New World Phileurini, Zootaxa 4363 (2) : -

Phileurus truncatus (Palisot de Beauvois, 1806)

Third instar

( Figs 1–10 )

Material examined. One third instar with the following data: “FLORIDA: Alachua Co/Archer; 10-XII-1976 / rotten log of turkey oak/ Scarabaeidae / Phileurus truncatus /P.M. Choate collr.”. One third instar with the following data: “FLORIDA: Alachua Co. Archer; 20-II-2017 /in rotting pine wood in association with adult/coll. Oliver Keller”.

Description. Dorsal body length approximately 48 mm. Cranium: Width of head capsule 8 mm. Color yellowish brown ( Fig. 1 ). Surface moderately punctate on frons (F) (punctures separated by slightly more than a punctures diameter), epicranium (E) less densely punctate (most of the large punctures are near the frontal suture and less dense on posterior portions of the epicranium), postclypeus (PSC) with large punctures as dense as on the anterior portion of the frons, and labrum densely punctate. Epicranial suture (ES) and frontal suture (FS) distinct. Frons: Surface with 1 exterior frontal seta (EFS) ( Fig. 1 ). Anterior frontal setae absent. Two posterior frontal setae (PFS) on each side of frons. Each anterior angle (AAS) with 2 setae. Epicranium on surface with 3 dorsoepicranial setae (DES). About 10 total epicranial setae distributed irregularly. Eight paraocellar setae (POS) on each side, setae arranged in two distinct rows of four setae each. Ocellus (O) present. Clypeus: Form trapezoidal. Surface of postclypeus with no anterior clypeal setae (ACS) and 2 external clypeal setae (ECS) on both right and left side ( Fig. 1 ). Labrum: Surface slightly asymmetrical with lateral margins of labrum (and epipharynx) angulate on each side ( Fig. 1 ). One long posterior labral setae (PLS) on each side and about 10 posterolateral labral setae (PLLS). Epipharynx: Asymmetrical, left lateral margin slightly angulate ( Fig. 2 ). Haptomeral process (HP) ridge-like, not notched. Right and left chaetoparia (CPA) well developed, without sensillae; each with about 50 setae. Acroparia (ACR) with about 10 long, stout, slightly curved setae. Corypha (CO) with 8 short, stout, slightly curved setae. Left acanthoparia (ACP) with 10 short, curved, spine-like setae; right acanthoparia with 11 short, curved, spine-like setae. Pedium (P) longer than wide and without setae. Dexiotorma (DX) sclerotized, broad, and elongate. Laetorma (LT) shorter than dexiotorma (by approximately 1 mm). Pternotorma (PTT) rounded. Haptolachus (HL) lacking setae. Sclerotized plate (SP) of right nesium (RN) well developed, nearly half as broad at middle as the sense cone, sclerotized plate projected medially, half its length to sense cone. Sense cone (SC) a well-sclerotized, rounded plate. Left mandible: Form falcate ( Figs 3–4 ). Scissorial area with blade-like apical tooth (S1+S2 fused), separated from S3 by scissorial notch (SN), S4 below notch. S3 large and triangular. Scrobis (SCR) with 10 slender, long setae. Acia (AC) well developed and acute. Ventral surface with elongate, oval stridulatory area (STA) that are similar in width with about 52-54 narrowly separated, subparallel ridges. Preartis (PA) distinct, concave. Ventral process (VP) large, anterior portion subangulate. Brustia (BR) with about 15 long setae. Molar area with about 6 ventral molar setae. Molar lobe (ML) with a large, prominent anterior tooth, with apex weakly emarginate. Flattened posterior portion of subdivided molar with dorsal margin weakly depressed. Postartis (PTA) large, rounded. Right mandible: Form falcate ( Figs 5–6 ). Scissorial area with apical, blade-like tooth (S1+S2 fused), separated from S3 by scissorial notch, S4 below notch. S3 slightly smaller than on left mandible. Scrobis (SCR) with 8 long setae. Acia (AC) absent. Dorsal surface with 1 long seta posterior to base of S3. Preartis (PA) distinct, concave. Ventral surface with elongate-oval, stridulatory area (SA) with about 50 narrowly separated, subparallel ridges. Ventral process (VP) large, subangulate. Brustia with about 10–12 long setae. Molar area with about 6 ventral molar setae (VMS). Postartis (PTA) large, rounded. Maxilla and labium: Stridulatory area of left maxilla with row of 9–10 stridulatory teeth (SD), teeth becoming increasingly smaller basally; apical most tooth much larger than other teeth ( Fig. 7 ). Stridulatory area of right maxilla with row of 7 teeth. Glossa in dorsal view with about 40 setae; disc of glossa in dorsal view developed into a round mound. Hypopharyngeal sclerome (HSC) ( Fig. 8 ) symmetrical; apical portion of hypopharyngeal sclerome developed into a large, roughly symmetrical lobe, apex of this lobe is broadly emarginated and fits snuggly onto the glossal mound. Truncate process (TP) prominent, elevated slightly and produced. Lateral lobes with about 13 long setae on left side. Antenna: Antenna with 4 antennomeres; antennomeres I–II subequal in length, each slightly longer than antennomere III; length of terminal antennomere slightly less than length of antennomere III. Terminal antennomere on dorsal surface with 5 dorsal sensory spots (DSS) ( Figs. 9–10 ). Thorax: Prothoracic spiracle about 0.8–1.0 mm long, 0.6–0.7 mm wide; respiratory plate light brown. C-shaped, spiracular bulla rounded, barely elevated; respiratory plate with about 40 regularly edged holes across diameter at middle. Dorsum of pronotum and prescutum segments II and III each with transverse row of long slender setae. Legs: Coxa, trochanter, femur, and tibiotarsus of all legs with numerous long, stout, setae. Tarsal claws falcate, with 1 basal external seta and 1 internal, preapical seta. Protarsal, mesotarsal, and metatarsal claws equal in length. Abdomen: Abdominal spiracles slightly larger (1.1 mm long, 0.8 mm wide) than prothoracic spiracle, all abdominal spiracles subequal in size. Abdominal segments I–VIII each with multiple transverse rows of long, spine-like setae. Raster: Teger with short, spine-like setae projecting towards anal slit. Lower anal lobe entire, covered with short, stout setae like those of the raster; fringed posteriorly with longer, slender setae. Anal slit transverse.

Figures

FIGURES 1–2. Phileurus truncatus, third instar. 1, Structural features of the cranium and labrum. AAS—anterior angle setae; ACS—anterior clypeal setae; DES—dorsoepicranial setae; E—epicranium; ECS—exterior clypeal setae; EFS—exterior frontal setae; ES—epicranial suture; F—frons; FS—frontal suture; O—ocellus; PFS—posterior frontal setae; PLLSposterolateral labral setae; PLS—posterior labral setae; POS—paraocellar setae; PSC—post clypeus; 2, epipharynx. ACPacanthoparia; ACR—acroparia; CO—corypha; CPA—chaetoparia; DX—dexiotorma; HP—haptomeral process; HLhaptolochus; LT—laeotorma; PTT—pternotorma; SC—sense cone; SP—sclerotized plate; RN—right nesium.

FIGURES 3–6. Phileurus truncatus, third instar. 3, Left mandible, dorsal view; 4, left mandible, ventral view; 5, right mandible, ventral view; 6, right mandible, dorsal view. AC—acia; BR—brustia; ML—molar lobe; PA—preartis; PTApostartis; S 1 – 4 —scissorial teeth; SCR—scrobis; SN—scissorial notch; STA—stridulatory area; VMS—ventral molar setae; VP—ventral process.

FIGURES 7–10. Phileurus truncatus, third instar. 7, Maxillary stridulatory area. SD—stridulatory teeth; 8, labium and maxillae, dorsal view. HSC—hypopharyngeal sclerome; TP—truncate process; (9) antennomeres II–IV; 10, terminal antennomere.DSS—dorsal sensory spots.