Lissotes rudis Lea

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 : 354-355

Lissotes rudis Lea

Material examined. Three third instars, 41°13.524'S, 148°3.300'E. Murdochs Road, Goulds Country, Tasmania, April 2012. Voucher specimen: TMAG F6692.

Description. Body “C” shaped, translucent white, 10 abdominal segments; C-shaped cribiform spiracles on segments 1–9 ( Fig. 1 B). Total body length 31–35 mm; second abdominal segment width across dorsum 6.5–7.5 mm. Head ( Fig. 5 A). Light honey yellow, maximum head capsule width 5.0– 5.5 mm; frontal suture distinctly Vshaped, terminating in broad opening; mandibles chestnut-brown basally, apex black. Antennae ( Figs. 5 B–C). With 3 antennomeres, geniculate; proximal antennomere long, narrow basally with 12 dorsolateral setae; second antennomere clavate, oriented dorsally, uniformly covered with pores, some bearing tiny stiff spines, excluding the basal portion of the dorsal surface and the mediolateral surface. Large distal sensorium on apex; terminal antennomere small, cylindrical, bluntly-pointed apically, with 3 setae of even length oriented dorsolaterally, apex with single, short anteriorly oriented spine, 1–2 small tubercles, ventral surface with a small sensorium. Labrum. Light chestnut, symmetrical, anterior angles rounded, frontal margin crenulate, setose (bearing 10 pairs of long, ventrally oriented setae); dorsal surface with anteromedial pair of long setae, posterior-lateral group of 3 setae of uneven length joined by a loose medial row of 4 short lateral setae; posterior margin lacking setae. Clypeus. Chestnut-brown, short, wider than long. Maxilla. Cardo divided into 2 parts, with a single seta on posterior margin. Palpus with 4 palpomeres; distal palpomere heavily sclerotised and lacking setation; proximal palpomere with 4 setae (2 basal, 1 lateral, 1 ventral); palpomere 2 lacking setation; palpomere 3 with 2 ventrolateral setae distally. Palpifer with single seta ventrally, immediately posterior to base of galea. Stipes with up to 18 ventral setae of varying length. Galea terminates in a strong, heavily sclerotised spur; spur encircled by 4 long, sharp setae; dorsal aspect with broken row of 5 long, sharp setae; base venter with 9 sharp introrse medial setae. Lacinia terminates in a strong, heavily sclerotised spur; up to 15 medially oriented dorsal setae; 3 rows of sharp ventral spines, medial and lateral rows of 10 setae and an outer lateral row of 4 short setae. Labium. Quadrate, frontal margin slightly sinuate, multi-length setae sparsely distributed across frontolateral and anterior margins. Labial palps with 2 palpomeres, distal palpomere elongate, twice the length of basal palpomere, apically with several sensory organs. Epipharynx ( Fig. 5 D). Protophoba consisting of curved row of loosely-grouped, asymmetrical, tooth-like tubercles. Phoba with a single row (or grouped) introrse, tooth-like, spiked, or blunted tubercles of varying length. Chaetoparia covered with widely spaced, introrse spines of varying length. Haptomerum with 6–7 loosely-grouped, sclerotised sensory pores; lacking any spines or sensillae. Haptolochus, a single nesium, moderately sclerotised, covering the entire haptolachus and fringed by (7–11) sensillae of varying length. Pternotorme short, bluntly pointed, heavily sclerotised. Epitorma elongate, sharply-pointed, heavily sclerotised. Mandibles ( Figs. 5 E–G). Left mandible: 3 sharply pointed apical teeth, 2 incisors. Mola with a prominent 2-pointed cusp occupying the complete anterior section, cup elongate and narrow, deeply concave with a granular surface and a protruding dorsal overhang; 4 sensillae present in group on dorsum; a prominent red pore on the dorsal surface anterior to base of first incisor; 5 sensillae in scrobis, (1 anterior, 1 central, 3 basal) and a single, short sensilla ventral to the basal group. 3 short sensillae on ventral aspect, dorsolateral to the condyle. Right mandible: 2 apical teeth, no incisor. Mola bicuspid, divided into 2 granular, concave cups, separated by a transverse ridge and deep channel; 6 sensillae present in group on the dorsum; a prominent red pore dorsally, posterior to the base of the second apical tooth. 4 sensillae in scrobis, (1anterior, 1 central, 2 basal); 4 short ventral sensillae, dorsolateral to the condyle. Plectrum ( Fig. 5 H). 28–34 evenly-spaced, narrowly-separated, granular carinae. Right mesothoracic leg ( Fig. 5 I). Pars stridens ( Fig. 5 J). 13–16 obliquely curved rows of rounded granules, varying in length, distal two rows often very long. Rows occasionally broken or bifurcated posteriorly, occasionally with ungrouped, single granules present. Pretarsus. Heavily sclerotised, long and narrowly pointed, from a short basal section with 2 setae arising from the same ventral position on either side. Vestiture of abdominal sternite 10 ( Figs. 5 K–L). Encircled by a widely spaced band of setae of varying length, increasing in length caudally. Anal sclerite ( Fig. 5 M). Dorsal lobe present, much reduced; lateral lobes well developed, ventral apex with a small field of short setae; inflated, glabrous, oval pads flattened mesally; anal slit Y-shaped. Raster. Consisting of a well-spaced field of posteriomesally-directed spinules, interrupted at apex, increasing in length and density along tegillum; septula narrow, glabrous, becoming V-shaped towards campus. Herold’s organ (male only) occurs medially on the posterior section of the 9th abdominal sternite, appearing as a navel or caecum lacking sclerotisation but exhibiting a greater degree of pigmentation than the surrounding tissue.

Remarks. Lissotes rudis larvae display minor variation in labrum and epipharyngeal characters. Seta numbers on the labrum differed among individuals (12–15). Epipharyngeal characters displaying minor variation include the number of rows (1–3), pores (4–8), and presence of setae on the haptomerum. The plectrum displayed some variation in the number and shape of the granular carinae, the pars stridens exhibited less deviation in the number and form of the granular rows.

Figures

FIGURE 5. Third instar larva of Lissotes rudis. 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.