Mesystoechus Waterhouse, 1878

Allsopp, Peter G., 2021, The Australian endemic genera Mesystoechus Waterhouse, 1878, Amblochilus Blanchard, 1851, and Bilobatus Machatschke, 1970 revisited (Coleoptera Scarabaeidae: Rutelinae: Anoplognathini), Zootaxa 4965 (2), pp. 363-374 : 365-367

Mesystoechus Waterhouse, 1878

Mesystoechus Waterhouse, 1878: 227 .

Type species. Mesystoechus ciliatus Waterhouse, 1878 , by monotypy.

Diagnosis. Males. Anoplognathini: Schizognathina. Mentum strongly setose. Labial palp small, with 3 palpomeres. Maxillae with galeae small, not toothed; palps short, slender, with elongate, narrow dorsal sensorium on apical palpomere. Mandibles produced beyond clypeus, margins rounded. Antennae with 10 antennomeres, club slightly sinuate, much longer than shaft. Labrum produced beyond clypeus, setose, horizontal, transverse. Clypeus transverse, margin rounded in profile, weakly to moderately recurved. Clypeofrontal suture curved anteriorly, obscure in middle. Frons strongly punctate. Ocular canthi well developed, setose. Pronotum punctate, without or with only a trace of a median impressed line, basal ridge obsolete or very fine. Elytra heavily punctate, intervals costate, epipleurae nonmembranous, coarsely sculptured. Pygidium vertical, convex, with close, fine sculpturing. Thorax and abdomen with abundant long setae. Protibiae 3-dentate, without a spur, protarsi slender, tarsomeres 1–4 much longer than tarsomere 5, claws long, slender, sharp, subequal, larger with at least a trace of a minute tooth. Metatibiae 2-carinate, spurs long and sharp, metatarsi long and slender.

Females. Only that of M. costatus is known and it has the antennal club and tarsi reduced relative to those of the male. Although he listed no females, Carne (1958: 198) stated that the antennal club of males is much larger than in females.

Key to males

1 Pronotum brown to black with a green or coppery-green sheen; elytra with striae pale yellowish brown, costate intervals pronounced, deep brown ( Fig. 9 ); larger claws without a minute tooth; highlands of southeastern Queensland ...................................................................................... Mesystoechus costatus Carne, 1958

- Pronotum with a variable pattern of dark yellowish black, fully developed consisting at least of a median longitudinal zone broadening posteriorly and a pair of symmetrical lateral curved bands and a lateral patch on each side; elytra with intervals not differentially pigmented, intervals weakly costate; larger claws of mid tarsi with at least a trace of a minute tooth at about half to two-thirds length................................................................................... 2

2 Clypeus and V-shaped central section of frons yellowish brown, lateral frons dark brown to black ( Fig. 7 ); mentum glabrous, anterior margin evenly convex; anterior margin of upper section of clypeus weakly recurved ( Fig. 7 ); anterior margin of pronotum glabrous; coastal southeastern Queensland and northeastern New South Wales ..................................................................................................... Mesystoechus ciliatus Waterhouse, 1878

- Clypeus and frons black, with indistinct browner median patch ( Fig. 11 ); mentum with long setae, anterior margin slightly concave and notched in middle; anterior margin of upper section of clypeus strongly recurved ( Fig. 11 ); anterior margin of pronotum with setae near angles; inland southeastern Queensland .......... Mesystoechus lithgowae Allsopp new species

Figures

FIGURES 7–15. Mesystoechus species. 7–8, Mesystoechus ciliatus Waterhouse, 1878, male: 7, dorsal view; 8, lateral view; 9–10, Mesystoechus costatus Carne, 1958, male: 9, dorsal view; 10, lateral view; 11–14, Mesystoechus lithgowae, new species, male holotype: 11, dorsal view; 12, lateral view; 13, parameres, frontal view; 14, aedeagus, lateral view; 15, known distribution of Mesystoechus spp. in southeastern Queensland and northeastern New South Wales: yellow squares—M. ciliatus; blue triangles—M. costatus; red star—M. lithgowae. Figs. 7–14 photographed by Greg Daniels.