Hoplogonus vanderschoori Bartolozzi

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 : 353

Hoplogonus vanderschoori Bartolozzi

Material examined. Three third instars, 41°16.747'S, 147°56.436'E, Forest Lodge Road, Pyengana, Tasmania, April 2012. Voucher specimen: TMAG F6690.

Description. Total body length 34.0– 36.5 mm; second abdominal segment width across dorsum 9–10 mm, Head ( Fig. 4 A). Light honey-yellow, maximum head capsule width 5.5–6.5 mm. Antennae ( Fig. 4 B–C). Proximal antennomere narrow basally with 12 dorsolateral setae. Labrum. Group of 3 setae of varying length on mid lateral surface, anterior margin setose (bearing 14 setae), posteriolateral group of 6 long setae, posterior margin lacking setae; anterior median with a pair of long, stiff setae. Maxilla. Cardo with a single seta on posterior margin, lacking ventral setation. Palpus proximal palpomere with 3 pairs of ventrolateral setae of varying length; palpomere 2 without setation; palpomere 3 with 2 pairs of setae oriented anteriorly, located ventrolaterally, 1 pair each on distal and proximal region. Palpifer lacking setation. Galea with 25 medially-oriented, dorsal setae becoming heavily sclerotised and peg-like towards spur; base venter covered with 9 well-spaced setae, a single sharp seta near spur. Lacinia with up to 30 medially oriented dorsal setae of varying length, becoming heavily sclerotised and sharp towards spur; a row of thick, sharp, ventral spines extend towards spur. Labium. Bearing 2 posteriomedial setae; small, sparse setae medially; anterior and anteriolateral margins bearing sparse long setae. Epipharynx ( Fig. 4 D). Protophoba consisting of a curved row of loosely grouped, asymmetrical, tooth-like tubercles with 3 paired sets medially. Phoba with a single row of introrse, pointed spines. Chaetoparia with numerous evenly spaced, introrse setae of varying lengths. Haptomerum lacking spines or sensillae; with a central, loose group of 4–5 sensory pores. Haptolachus with a single nesium, broadly homologous sclerotised patch, covering 90%, no sensillae present. Pternotorme short, bluntly pointed and heavily sclerotised. Epitorma short, bluntly pointed and heavily sclerotised. Mandibles ( Figs. 4 E–G). Left mandible: 3 apical teeth, 1 incisor. Mola with large cusp occupying complete anterior section, cup deeply concave with granular surface, 12 mesally-directed sensillae in group on dorsum; a single, long sensilla arises from a deep pore distal to the base of the third apical tooth, 3 sensillae occupy the scrobis (2 basal, 1 long central). Right mandible: 2 apical teeth, no incisor. Mola bicuspid with division across the anterior section, a steep vertical ridge across the cusp. Larger posterior cusp concave, anterior cusp a steeply inclined notch, both with a granular surface. 15 mesally-directed sensillae present in a group on the dorsum, 4 sensillae in scrobis (3 basally, 1 long centrally). Plectrum ( Fig. 4 H). 38–42 evenly spaced, narrowly separated granular carinae; a pair of stout tubercles on the proximal margin. Right mesothoracic leg ( Fig. 4 I). Pars stridens ( Fig. 4 J). 12–21 obliquely curved rows of rounded granules, varying in length, often with short or broken rows, occasionally bifurcated anteriorly or posteriorly (more prevalent towards the proximal margin), often with ungrouped single granules between rows and at times accompanied by a tight field of smaller granules along the posterior edge and encompassing the distal margin. Vestiture of abdominal sternite 10 ( Figs. 4 K–L). Anal sclerite ( Fig. 4 M). Lateral lobes encircled by a sparse fringe of short setae increasing in length around ventral apex. Raster. Dense, uninterrupted field of posteromesally-directed spinules increasing in length along tegillum.

Remarks. Hoplogonus vanderschoori 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 molar cusps and the number of sensillae; however, the bicuspid right mola is a consistent character. Setation of the labrum differed among individuals (8–14). Epipharangeal characters displaying minor variation include the number and form of structures in the phoba and protophoba, the grouping and number of pores (4–8) and presence of setae on 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 4. Third instar larva of Hoplogonus vanderschoori. 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.