Astraeus (Astraeus) prothoracicus van de Poll, 1889

Volkovitsh, Mark G. & Bílý, Svatopluk, 2015, Larvae of Australian Buprestidae (Coleoptera). Part 5. Genera Astraeus and Xyroscelis, with notes on larval characters of Australian polycestine taxa, Acta Entomologica Musei Nationalis Pragae 55 (1), pp. 173-202 : 178-180

Astraeus (Astraeus) prothoracicus van de Poll, 1889

( Figs 21 , 30–31 , 47, 54 , 62 , 71 , 78, 86, 93–94, 108, 116–117)

Material examined. AUSTRALIA: WESTERN AUSTRALIA: Eneabba, 29.45°S 115.16°E, M. Peterson leg., Banksia menziesii R. Br. (Proteaceae) , ex cones, 2 specimens, most probably fully mature larvae (1 in NMPC, 1 in ZIN).

Description. Measurements (1 larva): body length 13.2 mm; width of prothorax 3.4 mm (larva in rather poor condition, so the measurements and ratios of external structures may be incorrect).

Larva of buprestoid type ( Fig. 21 ), morpho-ecological subtype 2 ( VOLKOVITSH 1979), prothorax poorly expanded, slightly wider than meso- and metathorax; body creamy-white; body sides with very sparse, short inconspicuous setae.

Head. Epistome strongly transverse, 4.7 times as wide as long; anterior margin deeply emarginate between ovale mandibular condyles, with short angular projections laterally; posterior margin slightly bisinuous; latero-posterior corners obtuse, rounded, projecting outwards; lateral margins of epistome emarginate; antennal incisions well-defined, deep; four epistomal sensilla arranged in two groups of two sensilla as in previous species. Clypeus ( Fig. 62 ) strongly transverse, 3.1 times as wide as long, membranous, glabrous.

Labrum ( Fig. 62 ) slightly transverse, 1.2 times as wide as long, nearly rectangular, lateral lobes not developed, anterior margin widely arcuate, lateral sides of labrum subparallel; palatine sclerites with well-defined and sclerotised, poorly separated branches; medial branches transverse; lateral branches strongly expanded at bases; medial sensilla of labrum (t = trichoid, c = campaniform): 1c-2t-3c, distance 1c–3c nearly equal to 1c– 2t, 2t long, extending anterior margin; antero-lateral sensilla of labrum, external group: (1t, 2c)-3t- 4t, 1t and 4t relatively short, 3t longest; internal group: (1c, 2t, 3t, 4t); labrum dorsally glabrous, ventrally (epipharynx) with large concentric areas of microspinulae, surrounding the pharynx.

Antennae ( Fig. 47 ): nearly as in previous species but basal antennomere 1.6 times as long as terminal antennomere; basal antennomere elongate, 1.4 times as long as wide, subcylindrical, with glabrous anterior margin bearing a few short microspinulae; terminal antennomere elongate, 1.5 times as long as wide at base, expanded anteriorly, anterior margin with dense microspinulae; apical cavity of terminal antennomere shallow, bearing long trichosensilla, nearly 1.5 times as long as antennomere itself; sensory appendage elongate, narrow, scarcely extending beyond anterior margin of cavity; two short palmate sensilla, basiconic sensilla invisible.

Mandibles ( Fig. 54 ) triangular, 1.2 times as long as wide, strongly sclerotised at apical half, black, basal half lighter, yellowish-brown; outer margin with one short seta above condyle; cutting edge with five teeth: apical tooth obtuse, two obtuse internal teeth (posterior poorly developed) dorsally and ventrally, both arising from the common base.

Hypostome poorly sclerotised, yellowish; internal margin of mandibular fossae not forming tooth-like projection, fossa regular, semilunar.

Maxillae (Figs 78, 86). Cardo subquadrate, nearly as wide as long, membranous, glabrous; latero-basal sclerite of cardo (Fig. 78) poorly defined, nearly missing, bearing two relatively long setae with elongate bases and one campaniform sensillum at base of outer seta. Stipes (Fig. 86) subquadrate, slightly wider than long; inner sclerite of stipes with well-defined, long internal process; apical seta of stipes as long as palpus, situated at anterior margin of stipes between the bases of palpus and mala; lateral seta short, situated at apex of lateral part of inner sclerite; external armament composed of fringe of sparse, short microspinulae anteriorly extending mala; internal armament composed of sparse, short microspinulae laterally; additional internal lobe absent. Palpus maxillaris (Fig. 86): basal palpomere nearly as long as apical palpomere; basal palpomere trapezoid, slightly transverse, 1.1 times wider than long; externally with a few short microspinulae at the base of apical seta, internally with short microspinulae along anterior margin; apical seta nearly as long as terminal palpomere; terminal palpomere subcylindrical, elongate, weakly narrowed apically, 1.8 times as long as wide, with approximately six short, peg-like apical sensilla of which two larger than others. Mala (Fig. 86) slightly elongate, feebly narrowed apically, 1.3 times as long as wide; inner sclerite of mala well- defined and sclerotised, subquadrate; external armament of mala composed of one campaniform sensillum, one short peg-like seta, five robust long setae, and short microspinulae apically; mala internally with three robust, short setae and without dense microspinulae along inner margin.

Labium ( Fig. 71 ). Prementum slightly transverse, 1.4 times as wide as long; anterior margin widely arcuate, feebly emarginate at middle, with broadly rounded corners; lateral sides widely arcuate, subparallel; with small areas of microspinulae dorsally (hypopharynx), completely glabrous ventrally; corner sclerites of labium inconspicuous, with anterior part nearly transparent, apical setae relatively long but not extending anterior margin of prementum; five campaniform sensilla situated below the bases of apical setae, three apical (two with long bases) and two basal. Postmentum with single, asymmetrically situated short seta (? artefact,? second seta missing).

Thorax ( Figs 30–31 , 93–94). Slightly expanded, flattened, prothorax 1.1 times wider than mesothorax which is as wide as metathorax and both slightly wider than 1 st abdominal segment; rudiments of legs ventrally on all thoracic segments (Fig. 94). Prothorax transverse, 1.9 times as wide as long; anterior membrane glabrous with sparse short setae; lateral sides evenly rounded, with very sparse, short, whitish setae. Both dorsal and ventral plates poorly defined, unsclerotised, colorless, limited with oblique folds. Pronotal plate (Fig. 93) glabrous, bearing sparse short setae anteriorly, honeycomb, superficial cuticular sculpture along the groove, and numerous irregular rugae. Pronotal groove uniramous, well-defined and sclerotised, yellowish-brown, with subparallel sides, slightly expanded apically and basally, not forked at base. Prosternal plate similar to pronotal one. Prosternal groove uniramous, yellowish-brown, nearly subparallel, not T-shaped. Mesothorax ( Figs 30–31 ) stongly transverse, 3.8 times as wide as long and 1.1 times wider than metathorax; glabrous, bearing isolated short setae; ambulatory pads transverse, poorly developed both dorsally and ventrally. Metathorax ( Figs 30–31 ) transverse, 2.0 times as wide as long and 1.1 times wider than 1 st abdominal segment; lateral sides with sparse short whitish setae; both dorsal and ventral sides of metathorax with poorly defined, transverse plates separated by medial depression dorsally and ventrally.

Abdomen ( Fig. 21 ) flattened, segments 1–8 weakly transverse, slightly wider than long; all segments with very small areas of poorly defined microspinulae near the spiracles and inconspicuous, medial microspinulate stripes both dorsally and ventrally; lateral sides with sparse short whitish setae and poorly defined microspinulae; 1 st abdominal segment transverse, 1.8 times as wide as long and nearly as wide as segments 2–8, ambulatory pad poorly marked. Abdominal segments 2–8 transverse, 1.6–2.2 times as wide as long. 9 th abdominal segment strongly transverse, 2.3 times as wide as long; 10 th abdominal segment transverse, 1.6 times as wide as long, with small, poorly defined microspinulate areas and with vertical unsclerotised anal rim.

Spiracles ( Figs 116–117 ). Mesothoracic spiracles ( Fig. 116 ) of buprestoid, multiloculate type, renifom, narrow, moderately transverse, 2.5 times as wide as long, situated on sides of anterior part of mesothorax, with cancellate peritreme and a few poorly developed, branched trabeculae; spiracles surrounded with poorly defined microspinulate areas. Abdominal spiracles ( Fig. 117 ) of uni- or biloculate type, irregulary ovale, slightly transverse (that on the 1 st abdominal segment 1.3 times as wide as long), situated dorsally in depressions on abdominal segments 1–8, with poorly defined peritreme and a few unbranched trabeculae; adjacent cuticle with poorly defined microspinulate areas.

Proventriculus cordiform, internally with moderately developed dorsal and ventral central stripes. Main fields with very dense, robust, isolated microteeth situated on tubercles (Fig. 108); their margins with smaller and sparser, reduced teeth and enlarged tubercles, anteriorly with fine microspinulae arranged in rows, posteriorly with very long microspinulae changing to microteeth. Central stripes developed on both sides; dorsally with long and dense microteeth situated on elongated tubercles, similar to these on main fields but sparser and longer; ventrally with scale-like tubercles and long fine spinulae, occasionally situated in rows. Glabrous areas extensive, with long undulate rugae.

Figures

Figs 20–27. Astraeini, Xyroscelidini, Prospherini, Polycestini, Haplostethini, and Paratrachyini, larval habitus (dorsal view). 20 – Astraeus (Depollus) aberrans van de Poll, 1886 (Australia); 21 – A. (A.) prothoracicus van de Poll, 1889 (Australia); 22 – Xyroscelis crocata Gory & Laporte, 1839 (Australia); 23 – Xyroscelis sp. (Australia); 24 – Blepharum sainvali (Bílý, 2000) (New Caledonia); 25 – Paratrachys (P.) hederae Saunders, 1873 (Japan); 26 – Polycesta (Tularensia)?elata LeConte, 1858 (U.S.A.); 27 – Mastogenius texanus Bellamy, 2002 (U.S.A.). Photo: M. G. Volkovitsh.

Figs 28–43. Astraeini, Xyroscelidini, Prospherini, Polycestini, Haplostethini, and Paratrachyini, thoracic and basal abdominal segments (dorsal and ventral views).28, 29 – Astraeus (Depollus) aberrans van de Poll, 1886; 30, 31 – A. (A.) prothoracicus van de Poll, 1889; 32, 33 – Xyroscelis crocata Gory & Laporte, 1839; 34, 35 – Xyroscelis sp.; 36, 37 – Blepharum sainvali (Bílý, 2000); 38, 39 – Polycesta (Tularensia)?elata LeConte, 1858; 40, 41 – Mastogenius texanus Bellamy, 2002; 42, 43 – Paratrachys (P.) hederae Saunders, 1873. Photo: M. G. Volkovitsh.

Figs 44–60.Astraeini, Xyroscelidini, Prospherini, Polycestini, Haplostethini, and Paratrachyini, hypostome, epistome (details), antennae, and mandibles. 44 – Astraeus (Depollus) aberrans van de Poll, 1886, tooth-like projection of hypostome (arrow); 45 – Xyroscelis sp., lateral projection of epistome (arrow). 46–52 – antennae: 46 – Prospheres aurantiopicta Laporte & Gory, 1837; 47 – A. (A.) prothoracicus van de Poll, 1889; 48 – Xyroscelis crocata Gory & Laporte, 1839; 49 – Xyroscelis sp.; 50 – Strigoptera bimaculata (Linnaeus, 1758); 51 – Mastogenius texanus Bellamy, 2002; 52 – Paratrachys (P.) hederae Saunders, 1873. 53–60 – mandibles (left): 53 – Astraeus (D.) aberrans; 54 – A. (A.) prothoracicus; 55 – Xyroscelis crocata; 56 – Xyroscelis sp.; 57 – Prospheres aurantiopicta; 58 – Strigoptera bimaculata; 59 – Mastogenius texanus; 60 – Paratrachys (P.) hederae. Photo: M. G. Volkovitsh.

Figs 61–68. Astraeini, Xyroscelidini, Prospherini, Polycestini, Haplostethini, and Paratrachyini, labrum dorsally: 61 – Astraeus (Depollus) aberrans van de Poll, 1886; 62 – A. (A.) prothoracicus van de Poll, 1889; 63 – Strigoptera bimaculata (Linnaeus, 1758) (arrows show campaniform sensilla); 64 – Xyroscelis crocata Gory & Laporte, 1839; 65 – Xyroscelis sp.; 66 – Prospheres aurantiopicta Laporte & Gory, 1837; 67 – Mastogenius texanus Bellamy, 2002; 68 – Paratrachys (P.) hederae Saunders, 1873.

Figs 69–76. Astraeini, Xyroscelidini, Prospherini, Polycestini, Haplostethini, and Paratrachyini, labium ventrally: 69 – Prospheres aurantiopicta Laporte & Gory, 1837; 70 – Astraeus (D.) aberrans van de Poll, 1886; 71 – A. (A.) prothoracicus van de Poll, 1889; 72 – Strigoptera bimaculata (Linnaeus, 1758) (arrows show campaniform sensilla); 73 – Xyroscelis crocata Gory & Laporte, 1839; 74 – Xyroscelis sp.; 75 – Paratrachys (P.) hederae Saunders, 1873; 76 – Mastogenius texanus Bellamy, 2002. Photo: M. G. Volkovitsh.

Figs 114–129. Astraeini, Xyroscelidini, Prospherini, Polycestini, Haplostethini, and Paratrachyini, mesothoracic (114, 116, 118, 120, 122, 124, 126, 128) and abdominal (115, 117, 119, 121, 123, 125, 127, 129) spiracles: 114, 115 – Astraeus (Depollus) aberrans van de Poll, 1886; 116, 117 – A. (A.) prothoracicus van de Poll, 1889; 118, 119 – Xyroscelis crocata Gory & Laporte, 1839; 120, 121 – Xyroscelis sp.; 122, 123 – Prospheres aurantiopicta Laporte & Gory, 1837; 124, 125 – Strigoptera bimaculata (Linnaeus, 1758); 126, 127 – Mastogenius texanus Bellamy, 2002; 128, 129 – Paratrachys (P.) hederae Saunders, 1873. Photo M. G. Volkovitsh.