Hoplogonus simsoni Parry

Richards, Karen & Spencer, Chris P., 2014, Descriptions and key to the larvae of the Tasmanian endemic genus Hoplogonus Parry (Coleoptera: Lucanidae), and comparison with the sympatric Lissotes rudis Lea, Zootaxa 3884 (4), pp. 347-359 : 351-353

Hoplogonus simsoni Parry

Material examined. Three third instars, 41°13.524'S 148°3.300'E, Murdochs Road, Goulds Country, Tasmania, April 2012. Voucher specimen: TMAG F6688.

Description.Total body length 27.0– 35.5 mm; second abdominal segment width across dorsum 9.0– 11.5 mm. Head ( Fig. 3 A). Golden honey yellow, maximum head capsule width 4.0– 6.5 mm. Antennae ( Figs. 3 B–C). Second antennomere densely covered with pores bearing tiny, stiff spines on the ventral and lateral aspects. Labrum. 18 setae on frontal margin, posterior group of 4 long anteriorly oriented setae, medial pair very long. Maxilla. Cardo with single seta on posterior margin, lacking ventral setation. Palpus proximal palpomere with a pair of ventral and lateral setae; palpomere 2 with a single short ventral seta; palpomere 3 with 2 vetrolateral setae on distal region. Palpifer with a single ventral seta, immediately posterior to the base of the galea. Galea with up to 22 dorsal setae oriented medially, becoming heavily sclerotised; blunt peg-like near spur; spur encircled by 3 thick, long setae; base venter covered with 14 well-spaced setae; row of 3 heavily sclerotised spines extends towards spur. Lacinia with up to 26 medially oriented dorsal setae of varying length, becoming heavily scleritised, blunt and peg-like in a lateral row towards spur; up to 20 long sharp ventral spines mediolaterally, becoming denser basally; a row of thick black spines extends anteriorly, becoming blunt and peg-like towards spur. Labium. Bearing multiple length setae sparsely distributed across surface. Epipharynx ( Fig. 3 D). Protophoba consisting of a curved, asymmetrical row of 20 mostly paired, tooth-like projections. Phoba with a loose row of unevenly spaced, introrse, sometimes paired tubercles, many pointed. Chaetoparia densely covered with introrse, evenly spaced spines of varying length. Haptomerum with 3 loose rows of 4–5 evenly spaced, long setae; anterior to a group of 4–5 sensory pores. Haptolachus with single nesium, moderately sclerotised, covering the mid portion; 2 more heavily sclerotised linear areas in the left haptolachus; no sensillae present. Pternotorme relatively short, bluntly pointed and heavily sclerotised. Epitorma short, bluntly pointed and heavily sclerotised. Mandibles ( Fig. 3 E–G). Left mandible: 2 apical teeth, 1 incisor. Mola with large cusp occupying complete anterior section, cup deeply concave with granular surface; 11 sensillae present on dorsum, 3 sensillae of uneven length in scrobis. Right mandible: 1 apical tooth, no incisor. Mola cusp not present, slightly concave with granular surface; 12 sensillae on dorsum; a single, long sensilla in scrobis. Plectrum ( Fig. 3 H). 46–49 evenly spaced, narrowly separated granular carinae; a pair of stout tubercles at proximal extremity. Right mesothoracic leg ( Fig. 3 I). Pars stridens ( Fig. 3 J). 15–21 obliquely curved rows of rounded granules, varying in length, occasionally broken or bifurcated anteriorly or posteriorly (more prevalent towards proximal margin), often with ungrouped single granules or confused groups of granules between rows and at distal margin. Vestiture of abdominal sternite 10 ( Figs. 3 K–L), Anal sclerite ( Fig. 3 M). Lateral lobes encircled by a sparse fringe of short setae. Raster. Dense field of posteriomesally-directed spinules, interrupted at apex, increasing in length along tegillum.

Remarks. Hoplogonus simsoni larvae display considerable variation in mandible, labrum, epipharynx, and plectrum characters. Mandibular variation is confined to the size and shape of the apical teeth, the form of the mola cusps and the number of sensillae. Setation of the labrum differed among individuals (12–19). Epipharangeal characters displaying minor variation include the number and form of structures in the phoba and protophoba, the number of rows (2–4), pores (3–7), and setae (0–5) of the haptomerum and the density of setae in the chaetoparia.

Whilst the plectrum was relatively consistent in the number and shape of the granular carinae, the pars stridens exhibited considerable variation in the number and form of the granular rows.

Figures

FIGURE 3. Third instar of Hoplogonus simsoni. A) Head capsule (mandibles retracted); B) left antenna, dorsal; C) left antenna, ventral; D) epipharynx; E) mandibles, ventral; F) mandibles, dorsal; G) mandibles, mesal; H) plectrum on right metatrochanter; I) right mesothoracic leg; J) pars stridens on right mesocoxa; K) abdominal sternite 10, anal segment, lateral; L) abdominal sternite 10, posterior view; M) abdominal sternite 10, anal sclerite displaying raster. Scale bars = 1 mm unless specified.