Liomenochilus ongi Hutchinson & Allsopp, 2022

Hutchinson, Paul M. & Allsopp, Peter G., 2022, Liomenochilus ongi (Coleoptera: Scarabaeidae: Melolonthinae: Systellopini), a new genus and new species from northern Western Australia, Zootaxa 5100 (1), pp. 119-128 : 122-123

Liomenochilus ongi Hutchinson & Allsopp , new species

( Figs. 1–11 )

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Type series. Holotype male. AUSTRALIA. WESTERN AUSTRALIA. “Carlton Hill Stn. [Station] WA. -15.535, 128.647 14.Mar.2021 S. Ong | PMH Coll # MEL 1511 | genitalia on card” [in WAM].

Paratype male: same data as holotype, except MEL 1512 [in PMH].

Description of holotype male ( Figs. 1–9 ). Length 11.6 mm, pronotal width 4.65 mm (widest at midlength), elytral width 4.9 mm (widest a base). Head, labrum, clypeus, frons and disc of ocular canthus brown yellow; clypeus with margins and frontal suture brown; base of frons and margins of ocular canthi black; antennae brown; pronotum yellow with broad medial vitta black; scutellum black; elytra yellow-brown with margins broadly black and suture broadly black; venter with pronotal hypomera, mesosternum medially, metasternum laterally, mesepimeron, metepisternum, abdominal ventrites (last ventrite with dark median patch) and pygidium yellow; mesosternum anteriorly and laterally, metasternum medially and sternites black; coxae dark brown to black; femora yellow with disc dark brown; tibiae yellow with apices of denticles, spurs and setae brown; tarsomeres yellow with apices and claws brown. Disc of mentum punctate bearing long setae, apex acute; labial palps small, cylindrical. Maxillary palpomere 4 as long as palpomere 2, longer than palpomere 3, apex of palpomere 4 with circular sensorium. Mandibles setose on lateral face. Antennae with 8 antennomeres, club 3-lamellate, lamellae of club 2x as long as shaft; antennomere 1 of shaft longer than antennomeres 2–3 combined; antennomeres 1–2 bearing sparse, long setae. Labrum reflexed in relation to clypeus, dorsal surface smooth, glabrous, laterally slightly reflexed, anterior margin evenly shallowly arcuate, lateral margins straight, clypeal suture effaced (only visible on lateral declivity), length:width ratio 0.34:1; anterior surface with transverse row of stout, pointed spines along ventral margin. Clypeus with anterior angles indistinct, continuous with labrum, widest at base, dorsal surface with posterior half rugulose, setose, lateral surfaces with setose punctures. Clypeofrontal suture not ridged, straight in middle but posteriorly directed near canthus. Frons rugose, with short setae; ocular canthus angulate to clypeus, extending across half of eye width, at about half eye height. Pronotum with disc sparsely micropunctate, punctures becoming larger and denser anteriorly and laterally, glabrous, with sparse, single row of long setae along all margins, posterior margin continuously convex arcuate to midlength then linear to anterior margin; posterolateral angles not defined, anterior angles forming right angles, widest at midlength, length:width ratio 0.6:1; pronotal hypomera with long setae. Scutellum U-shaped, disc sparsely punctate, setose. Elytral apices rounded, sutural striae obsolete; elytral striae indistinct, 6 striae between suture and humerus with further 2 laterad to humerus, all with micropunctures, interstices with numerous micropunctures, surface smooth becoming rugose in lateral half, glabrous; spines present along full length of epipleurae and posterior quarter of suture. Pygidial longitudinal rugosity bearing sparse, long setae. Setae sparser and shorter on abdominal ventrites than on thorax. Protibiae with line of sparse setae along midline in basal half, 1 tooth in addition to long, apical tooth, distal spur reaching midlength of tarsomere 3. Metacoxae without defined lateral margins. Metafemoral length:width ratio 1.65:1. Metatibial length:width ratio 1.06:1, apical spurs long, parallel, apices acute, lower spur 1.5 x length of upper spur. Parameres reflexed about 20° at half length, dorsal cleft in apical half, each paramere parallel sided, apices rounded.

Variation. The paratype differs from the holotype in the following characters: missing left elytron; body 11.5 mm (head hypognathous); pronotal width 4.75 mm, length 3.0 mm; elytral width 5.1 mm. coxae brown; femoral disc non-maculate; protibial spur reaching apex of tarsomere 2.

Etymology. Named in honour of the collector, who captured both specimens of this new species and who has been supportive of several taxonomists who have described species from freely supplied specimens. A noun in the genitive case.

Distribution. Known only from the type locality ( Figs. 10–11 ); it has a Köppen-Geiger climate of Bsh (hot semi-arid) verging on Aw (savannah) ( Beck et al. 2018).

Remarks. Males of Liomenochilus ongi differ from the other systellopine genera by having the labro-clypeal suture effaced dorsally and the antennae of 8 antennomeres with a 3-lamellate club. Unlike in some other groups of melolonthines, the systellopines show only minor differences among species in the shape of the parameres – most have long, narrow parameres that are slightly recurved.

Both specimens were collected at light on the one occasion.

Figures

FIGURE 10. Type locality of Liomenochilus ongi Hutchinson & Allsopp, new species (photograph by S. Ong).

FIGURE 11. Liomenochilus ongi Hutchinson & Allsopp, new species, known distribution (blue dot) in northwestern Australia.

FIGURES 1–7. Liomenochilus ongi Hutchinson & Allsopp, new species, holotype male. 1, dorsal view; 2, ventral view; 3, lateral view; 4, head, dorsal view; 5, head and pronotum, oblique view; 6, pygidium; 7, label.

FIGURES 8–9. Liomenochilus ongi Hutchinson & Allsopp, new species, holotype male, aedeagus. 8, dorsal view; 9, lateral view.