Ancyrona diversa Pic, 1921

Č, Ji Ř Í Kolibá & Zaitsev, Artem A., 2010, A description of a larva of Ancyrona diversa Pic, 1921 and its phylogenetic implications (Coleoptera: Trogossitidae), Zootaxa 2451, pp. 53-62 : 55-59

Larva of Ancyrona diversa Pic, 1921

Specimens examined: Five larval specimens: “Primorskyi krai, Lazovskyi zapovednik; Under the bark of Quercus mongolica ; 43°15'17"N, 134°07'59"E; A. Zaitsev; 08.VIII.2007 ”. Adult specimen: “Primorskyi krai, Lazovskyi zapovednik; on the bark of Quercus ; 43°00'34"N, 134°07'43"E; K. Makarov; 9.VII.2005 ”.

Description: Measurements (larger specimen): Body length (incl. mandibles and antennae) 7.3 mm, cranium length (without mandibles and antennae) 0.6 mm, cranium width 0.7 mm, thorax length 1.2 mm, abdomen length (incl. urogomphi) 5.2 mm, urogomphi length c. 0.2 mm.

Coloration and pubescence ( Figs 2–7 ): Head, urogomphi and dorsal part of abdominal segment IX heavily sclerotized, brown; prosternum, protergum and mesotergum with weakly sclerotized yellow-brown plates; metathorax and abdomen up to segment VIII yellowish white. Cranium with long sparse pubescence (c. 24 setae) situated laterally and along anterior margin; thorax with 2 long setae at each side and 2–5 short setae situated nearby; legs with few long setae; abdominal segments I–VIII with about 5 long setae situated dorsolaterally at each side; abdominal segments IX–X at sides densely and longly pubescent, urogomphi also with several setae.

Head ( Figs 4, 5 ): Cranium wider than long, lateral sides rounded (convex); two stemmata occur at each side; frontal arms V-shaped, nearly straight; epicranial stem minute (nearly absent); median endocarina present, extending to 3/4 of cranium length; frontoclypeal suture absent; gular sutures widely separated at base, strongly convergent, extending to approximately midpoint of cranium; hypostomal rods distinct, nearly reaching base of cranium; paragular sclerites absent.

Antennae ( Figs 9, 10 ): 3-segmented, 1st antennomere longer than 2nd, the latter as long as 3rd; sensory appendix relatively large, extending approximately to midpoint of 3rd antennomere.

Mandible ( Figs 8, 9 ): with two sharp apical teeth situated side by side (in horizontal axis); two large blunt medial teeth present; mola absent; prostheca (lacinia mandibulae) plumose, long.

Maxilla ( Figs 13 , 14 ): mala small, blunt, with approximately 5 clavate setae along outer margin and numerous hair-like setae in centre; pedunculate seta present but small and pale; small pigmented area situated in inner basal corner; palpi 3-segmented; cardo and stipes distinctly separated; cardo nearly as large as stipes.

Labium ( Fig. 14 ): ligula indistinct – small, pale, membranous, finely pubescent; palpi 2-segmented; prementum longitudinaly divided into two parts; postmentum somewhat shorter than stipes.

Labrum ( Figs 12 , 15 ): free; epipharynx with about 8 clavate setae along anterior margin, ciliate along lateral margins; labrum dorsally with 4 long hair-like setae at disc; rigid pigmented tormal plate situated between pair of short simple tormal sclerites.

Thorax ( Figs 2, 3 , 19 ): protergum weakly sclerotized and pigmented, tergal plate longitudinaly divided by medial suture; mesotergum with two small hardly visible softly sclerotized plates in posterior half; metatergum without sclerites. Prosternum with distinct elongate sclerotized plate; meso- and metasterna without visible sclerites.

Thoracic endoskeleton ( Fig. 19 ): Prothorax with pleural apodemes triangular, elongated, sharpened apically; epimeral and episternal apodemes poorly developed. Meso- and metathorax: episternal apodemes well developed, distinctly extended; epimeral apodemes as on prothorax; pleural apodemes absent. Mesothoracic spina trapeziform, well developed; metathoracic spina much smaller, oval.

Legs ( Fig. 11 ): Coxae projecting; trochanteri oblong (not triangular); femora shorter than tibiae; tarsunguli with single seta.

Abdomen ( Figs 6, 7 , 18 ): segments I–VIII membranous, terga without sclerites or pigmented plates; spiracles annular-biforous; segment IX with tergum transversely divided into basal disciform sclerite and apical sclerite bearing pair of hooked urogomphi; distinct median process with glandular opening present between urogomphi (no other glandular openings observed in abdominal segments); large shallow pit occurs in centre of apical sclerite; urogomphi smooth, turned upwards, well-developed.

Alimentary canal ( Figs 16 , 17 ): Ventriculus with micropapillae, its surface not smooth and not with netlike structure; ileum distinctly curved; four Malpighian tubules observed, probably all of the same length.

Biology: Larva found under oak bark ( Quercus mongolica ). Predatory – distinct remnant of arthropod antenna or palpus were observed inside ventriculus together with crushed remnants of arthropod cuticle inside ventriculus and ileum. Adult ( Fig. 1 ) collected on dry oak log at night, they are probably predatory in the same way as other species of Ancyrona ( Kolibáč 2005, 2007).

Figures

FIGURES 1 – 7. Adult: (1) habitus dorsal. Larva: (2) habitus dorsal; (3) habitus ventral; (4) head dorsal; (5) head ventral; (6) abdominal apex dorsal; (7) abdominal apex ventral.

FIGURES 8 – 13. Larva: (8) right mandible dorsal (turned 180 ° horizontally); (9) left mandible and antenna ventral; (10) right antenna; (11) anterior leg; (12) labrum; (13) maxilla.

FIGURES 14 – 16. Larva: (14) labium and right maxilla; (15) labrum and epipharynx; (16) alimentary canal from half of ventriculus to rectum (Malpighian glands schematically).

FIGURES 19 – 24. Thoracic endoskeleton of Trogossitidae larvae (schematically): (19) Ancyrona diversa; (20) Grynocharis oblonga; (21) Temnoscheila japonica; (22) Lepidopteryx squamulata; (23) Thymalus limbatus; (24) Peltis grossa.

FIGURES 17 – 18. Larva: (17) alimentary canal from half of ventriculus to rectum; (18) surface of abdominal segment VI and detail of spiracle.