Grandaustralis boomerang Hutchinson & Moeseneder

Hutchinson, Paul M. & Moeseneder, Christian H., 2013, Grandaustralis, a new genus and Grandaustralis boomerang, a new species of Cetoniinae (Coleoptera: Scarabaeidae) from Western Australia, Zootaxa 3669 (1), pp. 17-26 : 20-25

Grandaustralis boomerang Hutchinson & Moeseneder , new species

( Figs 1–8 , 12 )

Material examined (40 specimens). Holotype, male: AUSTRALIA. Moir Road, 8 km S of Ravensthorpe, W.A., 16.ii.2008, P. Hutchinson, CET0342 [WAM]. Allotype, female: AUSTRALIA. Moir Road, 8 km S of Ravensthorpe, W.A., 18.ii.2008, P. Hutchinson, CET1798 [WAM]. Paratypes, 12 males and 1 female: AUSTRALIA. 5 males, Moir Road, 8 km S of Ravensthorpe, W.A., 15.ii.2008, P. Hutchinson, CET0347 [QDPC], CET0348 [MAGNT], CET0349 [BMNH], CET0350 [MVMA], 61005-015 [DAFWA]; 1 male, Moir Road, 8 km S of Ravensthorpe, W.A., 16.ii.2008, P. Hutchinson, CET0344 [PMH]; 6 males, Moir Road, 8 km S of Ravensthorpe, W.A., 17.ii.2011, P. Hutchinson & C. Moeseneder, 61005-019 [AMS], 61005-023 [SAM], T159370 [QM], 61005- 0 0 1 [ANIC], 61005-002, 61005-007 [MIC]; 1 female, Lookout Hill, 3 km N of Hopetoun. W.A., 9.ii.2003, P. Hutchinson, CET0343 [PMH]. Additional material, 25 males: AUSTRALIA. 1 male, 10 km E of Jerramungup, W.A., 17.ii.1979, M. Golding [WAM]; 1 male, 51 km W of Ravensthorpe, W.A., 10.ii.1991, G.P. [WAM]; 1 male, 20 km SSW of Ravensthorpe, W.A., 21.ii.1986, M. Powell [WAM]; 2 males, S of Ravensthorpe, W.A., 16.ii.2008, P. Hutchinson [AIF]; 2 males, S of Ravensthorpe, W.A., 13.ii.2011, P. Hutchinson [RZ]; 5 males, Moir Road, 8 km S of Ravensthorpe, W.A., 15.ii.2008, P. Hutchinson, CET0346, CET0351, CET0352, CET0353, CET0354 [PMH]; 2 males, Moir Road, 8 km S of Ravensthorpe, W.A., 17.ii.2008, P. Hutchinson, CET0345, CET0355 [PMH]; 2 males, Moir Road, 8 km S of Ravensthorpe, W.A., 13.ii.2011, P. Hutchinson & C. Moeseneder, 60998-005, 60998- 0 0 6 [MIC]; 7 males, Moir Road, 8 km S of Ravensthorpe, W.A., 17.ii.2011, P. Hutchinson & C. Moeseneder, 61005-003, 61005-004, 61005-009, 61005-012, 61005-014, 61005-018, 61005-022 [MIC]; 1 male, Kundip, W.A., x.1936, J. Reeves, 13056 [DAFWA]; 1 male, Cape LeGrande, W.A., 13.i.2001, D. Kitchin, DK-CET001 [DKG].

Description of Holotype. Male ( Figs 1 , 3–8 , 12 ). Length 22.9 mm, width 13.8 mm. Head ( Figs 3–5 ). Clypeus black, bearing coarse, coalesced punctures; external apical face deep, vertical; lateral ridge linear, divergent from antennal insertion; disc with medial, longitudinal elevation from frons to pre-apical margin, gradual declivity laterally to abrupt, steep lateral and apical margins. Frons with distinct declivity to clypeus; bearing coarse punctures, coalesced medially; with sparse, black setae posterior to eyes. Ocular canthi bearing dense setae distally. Scape black, distally with cincta of very long, ginger setae. Pedicel black. Antennomeres 3–7 dark brown with few setae. Club reddish-brown, arcuate, same length as head; inner surface of antennomere 8 ( Fig. 4 ) with medial sensory setae from middle to apical margin; antennomere 10 with sensilla placodea on distal area of dorsal surface ( Fig. 5 ). Thorax. Pronotum burnt orange with darker margins and irregular, small, black macula pre-medially adjacent to lateral margins; basolateral margins linear, parallel, broadly arcuate medially then linear, narrowing at approximately 45° to apex; disc with punctures becoming rugose toward apicolateral angles; lateral areas with raised margins, both bearing short, pale setae. Scutellum black across base, along midline and apex, remainder brown, bearing short, pale setae; base with few punctures. Elytron burnt orange, covering abdominal sternites, setae pale, short, erect, becoming black in apical half; humeral umbone not distinctly raised; apical umbone immaculate, moderately pronounced; metacoxa barely exposed at subhumeral arch; costae 1 and 2 not raised, narrow, extending to pre-apex; sutural costa black near suture, not pronounced, linear punctate to apex of scutellum, bearing moderately long, pale setae becoming black and longer toward apex; humeral umbone dark brown-black; elytral punctures becoming rugose in lateral third from humeral to apical umbone. Wings smoky, darker apically. Pygidium burnt orange, concentrically rugose, bearing few pale, erect setae laterally, across base and apically; apical ridge bearing long, pale setae. Mesometasternal process absent, with low keel ( Fig. 7 ) between coxae. Metasternum black, with shallow depression along midline, entirely covered in long ginger pilosity; macropunctures medially, laterally rugose. Legs ( Fig. 6 ). Profemur dorsoventrally flattened, slightly tapering to apex, moderately punctate, becoming weakly rugose apically; moderately clothed with long, ginger pilosity. Protibia with teeth broad, equidistant, basal tooth shorter; dorsal surface with coarse macropunctures coalesced to form irregular longitudinal grooves, punctures smaller at base of teeth, clothed with few long, fine, black setae; ventral surface punctures not coalescing but rugose with long black setae along ventral ridge to inner edge; setal brush incomplete. Protarsomeres 1–5 shorter than tibia with few short, fine setae. Mesofemur dorsoventrally flattened, moderately broad, entire surface rugose; clothed with long, fine, ginger pilosity. Mesotibia ventral surface with inner half impunctate, glabrous; outer half with macropunctures basally coalescing, becoming smaller to impunctate towards apex; inner margin, dorsal surface and basal regions of ventral surface moderately clothed with long, ginger setae. Mesotarsomeres 1–5 slightly longer than tibia, bearing fine setae. Metafemur dorsoventrally flattened, moderately broad with convex anterior margin; posterior margin linear, moderately rugose, more so towards anterior margin; clothed with long, fine ginger pilosity. Metatibia ventral surface with inner third impunctate, outer 2/3 with macropunctures becoming small to impunctate towards apex; basal half bearing setae; inner margin, dorsal surface and basal half of ventral surface moderately clothed with long, ginger setae. Metatarsomeres 1–5 slightly shorter than metatibia; ventral surface bearing fine setae; dorsal surface distal apex bearing fine setae. Legs black except for brown region on distal half of dorsal surface of tarsomere 5 of all legs. Abdomen. Sternites black, with indistinct longitudinal abdominal groove, coarse punctures across basal 2/3 of all sternites; bearing long, pale setae laterally, becoming shorter and fewer medially; sternites 3–6 flattened medially. Genitalia ( Fig. 8 ). Allotype. Female ( Fig. 2 ). Length 22.0 mm, width 12.6 mm. Differs from holotype in the following characters. Clypeal disc more raised, lateral declivity shallower. Antennal club approximately half length of head with linear inner margin, distinctly arcuate outer margin. Pronotum, scutellum, elytra black. Elytra with rugose apicolateral margins. Pygidium black with dark brown apex, apex with paramedial depressions causing apex to appear medially produced. Abdominal sternites highly convex, evenly punctate across entire surface; with fewer, shallower punctures bearing long, pale setae. Protibia dorsal surface with macropunctures not coalescing to form longitudinal grooves, setae shorter, longer on ventral surface. Mesofemur scarcely rugose, bearing long, black setae. Mesotibia ventral surface with fewer punctures, restricted to basal half, setae black, longer on inner margin and dorsal surface, reduced to few very short setae on basal portion of ventral surface. Metafemur less rugose; setae black, shorter, sparser. Metatibia less punctate, longer and black setae on inner margin and dorsal surface, reduced to few very short setae on basal region of ventral surface. Metatarsomeres 1–5 shorter than tibial length. Color variation: elytra with few scattered brown macula in apical half subequal to size of punctures, pygidium entirely black.

It is noted that holotype and allotype sustained damage during shipping with the Australian Postal Service. The broken tarsomeres of each specimen were glued to a card and pinned under each specimen.

Variation in paratypes. Males. Length 18.5–24.5 mm, width 10.0– 13.8 mm. Coloration consistent within type series. Females. Length 22.0– 25.5 mm, width 12.6–14.0 mm.

Discussion. In approximately 87% of described Australian Schizorhinini, males and females are similar enough in behavior and appearance that sex determination requires close inspection. For these species, the flowers of blooming Myrtaceae in particular not only provide food (specifically nectar and pollen) but serve as a meeting ground and mating location. The effort required for males to locate females is low and the males antennae consequently are only slightly larger than those of females since they are probably not used in locating females. Netting these flowers usually yields approximately equal numbers of male and female specimens.

Extensive and easily visible sexual dimorphism in Australian Schizorhinini is known from the genera Diaphonia , Hemichnoodes Kraatz, 1880 , the species Pseudoclithria fossor (Lea, 1914) , Grandaustralis boomerang and an undescribed species that will be described later by the authors. While females of Octocollis setosus Moeseneder & Hutchinson, 2012 are unknown it is likely that the species also falls into this group since collecting on flowers for almost 50 years has not produced any females. The two sexes of these taxa, except Hemichnoodes , also show very different behavior.

Carne (1974) observed that within the Australian Scarabaeidae very similar patterns of behavioral and morphological specialisation between the sexes evolved independently in at least the subfamilies Dynastinae , Melolonthinae and Rutelinae . Many of these dimorphic traits are consistent with those observed in G. boomerang and the group of sexually dimorphic species: development of sensory organs and searching flight behavior in males; infrequent occurrence, reduced flight and sedentariness in females. It could not be determined whether females release pheromones but this is likely.

Several morphological and behavioral adaptations of male G. boomerang seem to be related to reproduction, particularly the task of locating females: the large number of specimens, size of antennae (few cetoniine species have antennae as large), constant searching flight behavior and fasting at the adult stage. Upon their discovery the authors initially believed female specimens of G. boomerang to be Dynastinae as they are black, stocky and well adapted to burying.

Krikken’s key (Krikken 1984) considers the shape of the pronotum as a character in separating Schizorhinini from Cetoniini . Based on pronotal shape only, Grandaustralis would fall under the Cetoniini in his key since the underdeveloped basolateral area of the pronotum results in a basolateral angle which is greater than 90 degrees. This is also true for the genera Chlorobapta Kraatz, 1880 and Neoclithria van der Poll, 1886, both placed in the Schizorhinini. However, since mesepimera are not well visible and the posthumeral elytral emargination is not well developed (two further characters separating Cetoniini and Schizorhinini in Krikken’s key) Grandaustralis is herein assigned to the tribe Schizorhinini.

Etymology. The shape of the male’s antennal club and its flight behavior of circling and returning are reminiscent of a boomerang , a weapon used by indigenous Australians.

Ecology and geographical distribution. Males were observed over several days at the Ravensthorpe, W.A. site flying from approximately 09:00 to 13:00 between mallee bushes and at the edge of lower, open heath areas at a height of approximately 1 m but never above taller vegetation. They were fast and strong flyers, capable of weaving skilfully between the vegetation ( Fig. 11 ). The flight pattern may have been dictated by the height at which the beetles were flying and the height of the vegetation since Hemichnoodes nigriceps (Blanchard, 1850) was observed flying similarly at this locality. Wing color, which is clear in H. nigriceps and smoky to light brown in G. boomerang , allowed differentiation of the two species in flight. On some days, over 100 male specimens of G. boomerang were observed and often several were seen flying at the same time. Occasionally a beetle circled a bush or a spot near a bush for up to two minutes before descending. Usually they continued in flight but very rarely a specimen was observed landing near the bush. Since females are of stocky build and have protibiae adapted to burying, it was assumed that they spend a majority of the time in the soil or decaying plant matter. However, a search for females on every part of the plant where males had landed, above and under the ground and in the soil around the bush, was unsuccessful and did not yield female specimens or any indication of breeding activity. During the days of observation at Ravensthorpe, trees and bushes were in bloom and attracted all other cetoniines known from this area ( Metallesthes metallescens (White, 1859) , Aphanesthes succinea (Hope, 1844) and H. nigriceps ), but G. boomerang were never observed feeding on the flowers or any other food source. It is likely that adult males never feed. The two known females were found walking on the ground from 14:30–16:00.

All recent specimens were collected during the hottest summer months, January and predominantly February. The specimen collected by J. Reeves is in poor condition, which suggests that it may have been collected dead. The date on its label, October, is not indicative of adult activity.

Grandaustralis boomerang is known only from the Goldfields-Esperance region in Western Australia. The area where G. boomerang has been collected falls into two climate zones as per Köppen-Geiger climate classification (Peel et al. 2007), Cold semi-arid climate (classification Bsk) and Warm temperate climate with dry summer (classification Csb). Average annual rainfall in this region is 400-600 mm.

Figures

FIGURES 1 – 2. Grandaustralis boomerang. 1 — holotype male; 2 — allotype female.

FIGURES 3 – 8. Grandaustralis boomerang male. 3 — head; 4 — sensilla trichodia on proximal surface of male antennomere 8. JEOL 6460 SEM, photograph by B. Cribb; 5 — sensilla placodea on distal area of dorsal surface of male antennomere 10. JEOL JSM- 7001 F SEM, photographs by B. Cribb; 6 — legs, a—proleg dorsal view, b—mesoleg ventral view, c—metaleg ventral view; 7 — area of mesometasternal process, ventral and lateral views; 8 — genitalia, dorsal and lateral views.

FIGURES 9 – 12. Grandaustralis boomerang. 9 — collection localities (red dots); 10 — habitat of type locality, south of Ravensthorpe, W. A.; 11 — male flight pattern; 12 — male after landing at Ravensthorpe, W. A.