Aurum Hutchinson and Moeseneder, 2019

Hutchinson, Paul M. & Moeseneder, Christian H., 2019, Aurum, a new monotypic genus of Cetoniinae (Coleoptera: Scarabaeidae) endemic to Western Australia, Australia, Zootaxa 4683 (2), pp. 277-285 : 278

Aurum Hutchinson and Moeseneder , new genus

( Figs 1–2 , 3 E–H)

http://zoobank.org/NomenclaturalActs/ C5CD012A-E445-4EA1-94E5-89394FB5C2ED

Type species. Aurum leonorensis Hutchinson and Moeseneder , new species, hereby designated.

Description. Length 15.5–21.5 mm. Form ovate. Colour yellow with black maculae. Head ( Fig. 3E ). Clypeus subquadrate (length to width ratio is subequal), clypeal ridge present, apically broadly arcuate (hemispherical); apex sinuate; disc coarsely punctate. Frons coarsely punctate. Antennal club enlarged in male, shorter than length of antennomeres 2–7. Thorax. Pronotum weakly transverse, hemispherical, narrow at base distinctly exposing mesepimeron; basomedian margin weakly concave-linear; lateral margins broadly arcuate; basolateral angles not pronounced; disc coarsely punctate. Scutellum equilaterally triangular. Elytron. Posthumeral arch arcuate, exposing metacoxa and sternites, broadly arcuate to apex; mesepimeron distinctly protruding; humeral and apical umbones moderately raised; costa indistinct, narrow, not raised; disc rugulose, punctate, eroding sutural margins. Mesosternal process present as short parallel structure with arcuate apex ( Fig. 3A compared with Figs. 3 B–D) level with mesocoxa. Legs ( Figs 3 F–H). Protibia tridentate; denticles acute. Mesotibia bidentate. Metafemur anterior margin arcuate. Metatibia elongate, bidentate. Tarsomeres normal, setose. Abdomen. Median groove shallow and broad. Metasternum sparsely punctate medially, denser rugulose laterally. Pygidium concentrically rugose. Genitalia ( Fig. 2 ). Phallobase 2x length of parameres, widest at apex; ventrally bearing sclerotization. Parameres parallel to apex, dorsal cleft basally broad and wide then attenuate to apex.

Classification. Aurum is placed in the tribe Schizorhinini , which is justified by the following combination of characters that exclude it from other tribes. Head unarmed; pronotum evenly convex, basolateral angle distinct, basolateral margin not angled or slightly angled anteriorly, base trisinuate; scutellum apex pointed; mesepimeron convex; elytron with subhumeral margin present; pygidium wider than long, apical portion reflexed, unadorned with crests or callosities, bearing conspicuous subconcentric striolations; mesocoxa widely separated; mesometasternal process basally broad with or without anterior development; metacoxae approximated; male genitalia with a parameral flap; length 10–60 mm; occurring in the Australasian Region.

Within Schizorhinini , Aurum is placed in the subtribe Schizorhinina due to lack of the posterior expansion of the basomedian lobe of the pronotum over the scutellum and the mentum apically bilobate.

Etymology. From the Latin noun (in singular nominative, neuter gender) for gold. It is a reference to the Goldfields-Esperance region and the Goldfields Highway along which the specimens were collected.

Generic diagnosis. Aurum males can easily be distinguished from other Schizorhinina genera by the presence of the following combination of characters. Clypeus subquadrate, apically arcuate, apex linear. Pronotum base narrow, exposing mesepimeron, parallel basolaterally, arcuate to anterolateral angles, appearing hemispherical. Elytra non-costate, posthumeral emargination arcuate, exposing sternites. Mesosternal process short, not surpassing mesocoxa, parallel-sided, apically arcuate. Protibia tridentate, mesotibia and metatibia bidentate. Parameres. Phallobase centrally with sclerotization, parameres parallel-sided, dorsal cleft wide at base and attenuate to apex.

Differential diagnosis. Aurum appears most similar to Diaphonia and Aphanesthes Kraatz, 1880 . Table 1 provides a differential diagnosis for these two genera. In Krikken (2018), Aurum keys to couplets 1b, 2b, 16b, 17b, 19a, 20a, 21a, Diaphonia and Chondropyga ; hence we also compare Aurum to the genus Chondropyga .

Figures

FIGURE 1. Aurum leonorensis holotype, male.

FIGURE 2. Aurum leonorensis holotype, male aedeagus. Black arrow indicates location of sclerotisation on phallobase.

FIGURE 3. Aurum leonorensis and comparison taxa selected characters. For descriptions of characters refer to Table 1. A, Aurum leonorensis schematic cap-shaped mesometasternal process; B, Aphanesthes and Diaphonia schematic fungiform mesometasternal process; C, Aphanesthes and Chondropyga schematic arrowhead-shaped mesometasternal process; D, Aphanesthes and Chondropyga schematic bud-shaped mesometasternal process; E, A. leonorensis head; F, A. leonorensis metaleg (setae on femur and tibia not shown); G, A. leonorensis mesoleg (setae on femur and tibia not shown); H, A. leonorensis proleg. Note: 5 mm scale applies to all leg drawings.