Hoplogonus bornemisszai 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 : 350-351

Hoplogonus bornemisszai Bartolozzi

Material examined. Three third instars, 41°14.260'S, 148°6.486'E, Terrys Hill Road, Goulds Country, Tasmania, April 2012. Voucher specimen: TMAG F6686.

Description. Total body length 27–29 mm; second abdominal segment width across dorsum 7–8 mm. Head ( Fig. 2 A). Light honey-yellow, maximum head capsule width 4–5 mm. Antennae ( Figs.2 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 11 setae), posteriolateral group of 6 long setae, posterior margin lacking setae; anterior median with a pair of long, stiff setae. Maxilla. Cardo with a pair of short setae on posterior margin and group of 5 setae oriented anteroventrally. Palpus proximal palpomere with pair of ventral and lateral setae; palpomere 2 with single, short, ventral seta; palpomere 3 with 2 ventrolateral setae distally. Palpifer with single seta ventrally, immediately posterior to the base of the galea. Galea with 14 dorsal setae oriented medially, becoming heavily sclerotised and thick, but sharply pointed towards 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 with18 medially oriented dorsal setae of varying length, becoming thick, blunt, and peg-like in a row, oriented laterally 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 4 small setae (2 posteriomedially, 2 medially); anterior margin densely clothed with large setae; 6–8 anterolateral setae of variable length. Epipharynx ( Fig. 2 D). Protophoba consisting of a curved row of loosely grouped asymmetrical tooth-like tubercules, 12 on each side, homogeneous, but groupings differ. Phoba with a single row of introrse, tooth-like tubercles. Chaetoparia covered with introrse, well-spaced spines of varying length, some broken. Haptomerum lacking spines or sensillae, with central group of 6 sensory pores. Haptolachus with a single nesium, sclerotised area covering 50%, no sensillae present. Pternotorme of intermediate length, bluntly pointed and heavily sclerotised. Epitorma short, bluntly pointed and heavily sclerotised. Mandibles ( Figs. 2 E–G). Left mandible: 2 apical teeth, 1 incisor. Mola with large cusp occupying complete anterior section, cup deeply concave with granular surface; 9 sensillae present in a group on dorsum, 3 sensillae in scrobis, (1 anterior, 2 basal). Right mandible: 1 apical tooth, no incisor. Mola cusp not present, slightly concave with granular surface; 6 sensillae in a group on the dorsum, 2 stiff sensillae in scrobis, (1 anterior, 1 basal). Plectrum ( Fig. 2 H). 36–39 evenly spaced, narrowly separated granular carinae. Right mesothoracic leg ( Fig. 2 I). Pars stridens ( Fig. 2 J). 16–22 obliquely curved rows of rounded granules, varying in length, occasionally bifurcate anteriorly or posteriorly, often with ungrouped single granules between rows. Vestiture of abdominal sternite 10 ( Figs. 2 K–L). Anal sclerite ( Fig. 2 M). Lateral lobes with ventral apex densely setose posterior to septula. Raster. Dense, uninterrupted field of posteromesally-directed spinules increasing in length along tegillum.

Remarks. Hoplogonus bornemisszai larvae display considerable variation in mandible and epipharyngeal 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. Epipharangeal characters displaying minor variation include the number and form of structures in the phoba and protophoba, the number of pores (5–11) and presence of sensillae in the haptomerum and the density of setae in the chaetoparia. The principal explanation for the discrepancies is likely to be wear resulting from feeding activity in granitic substrate.

Figures

FIGURE 2. Third instar of Hoplogonus bornemisszai. 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.