Cheiloxena insignis Blackburn, 1896

Reid, C. A. M. & Beatson, M., 2018, Revision of the Australian leaf beetle genus Cheiloxena Baly, 1860 (Coleoptera: Chrysomelidae: Spilopyrinae), Zootaxa 4497 (4), pp. 501-534 : 524-526

Cheiloxena insignis Blackburn, 1896

( Figs 7, 8 , 17 , 35 , 39, 40 , 47 , 56, 57 , 65 , 72, 77 )

Cheiloxena insignis Blackburn, 1896: 39 (type locality: Healesville , Victoria).

Material examined. Non-types (13): Australia: unlocalised: ♀/ Australie par Glason/ Cheiloxena insignis Black. / Museum Paris coll. H. Clavareau 1932/ (MHNP); ♀/ Cheiloxena westwoodii Baly / ex museo H. W. Bates 1892/ Museum Paris ex coll. R. Oberthur/ (MHNP); New South Wales: ♂/ Mittagong, Nov, C Oke (MVM); Victoria: Ƌ, 2♀*/ Victoria French/ Cheiloxena insignis Black. / Museum Paris coll. H. Clavareau 1932/ (MHNP); ♂/ Ferntree Gully, 16.x.1927, FE Wilson (ANIC); ♂*/ Lake Mountain, 26.i.2016, M Lagerway (AMS); ♀*/ Launching Place 9.ii.1903 / C. insignis f det C. Reid/ (MVM); ♂/ Millgrove 20.xi.1927 FE Wilson (ANIC); ♂/ Monbulk 4.x.1901 Jarvis (SAM); ♀/ Monbulk 7.x.1902 Jarvis (SAM); ♂*/ One Tree Gully VIC Ferntree Gully 14.x.1979 A [could be Acacia or Allocasuarina !] verticillata R. Patterson F110/ (ANIC).

Diagnosis. Cheiloxena insignis is distinguished by: upper and lower surfaces setose, not scaled; anterior margin of clypeus deeply excavate; pronotum without dorsal ridges but with 1–2 lateral tubercles; apical half of elytra not conspicuously tuberculate; elytral surface with erect setae.

Description. Length: male 7–9 mm, female 8–10.5 mm; body relatively flat in profile, length about 3.2x height; colour dull to shining black, tibiae, tarsi and maxillary palpi, sometimes antennomeres 8–11 and apex elytra, dark reddish-brown; with adpressed thick white setae (not scales), sparsely distributed on head, pronotum and venter, in discrete lateral and preapical patches on elytra; surface sculpture extremely variable: head and pronotum shining but often shallowly microreticulate; elytral background sculpture shining to dull, depending on depth of microreticulation, but apices of tubercles always smooth and shining, elytral punctures semi-striate or scattered.

Head ( Figs 7, 8 , 17 , 35 , 39, 40 ): distinctly narrower than pronotum in both sexes, width 0.9x (male) or 0.8x (female) pronotal width; densely punctured (punctures separated by about 1 diameter); with sparse white hair-like setae, denser at sides; narrow impunctate smooth area around antennal cavities; vertex and frons elevated between eyes, and flat to concave between antennae, without midline groove posteriorly but midline smooth in some specimens; eyes small, elongate-reniform, strongly laterally prominent, separated by 6 eye widths in male, 7 eye widths in female; gena at shortest point about 2/3 eye length in both sexes; genal lobe about 1.3x shortest length gena; antennae 5–6 socket diameters apart; antennae about 0.6x body length (male), or about 0.5x body length (female); all antennomeres dull, 1–7 sparsely and coarsely setose, 8–11 densely and finely setose; antennomeres 1 and 3–11 elongate, 2 quadrate>0.5x length 1, <0.5x length 3, male antennomeres 3–7 thicker and more compressed compared with female; relative lengths of antennomeres, with 3 longest in both sexes, and middle segments more unequal in length in female than male: male: 2 shortest, <8=9=10, <1, <4=6=11, <5=7, <3; female: 2 shortest, <8, <9=10, <1, <4=6, <5, <7=11, <3; clypeus with 2–3 pairs of long subapical setae; clypeal anterior margin semicircularly excavate in male, with shallower V-shaped emargination in females, exposing anteclypeus; male apical maxillary palpomere securiform with broad truncate apex.

Thorax ( Figs 7, 8 , 17 ): pronotum clearly transverse, width 1.1–1.3x length, greatest width at lateral median lobe or also anterior angle, sides contracted and straight behind middle; dorsum of pronotum distinctly demarcated, relatively horizontal compared with almost vertical hypomera; pronotal disc irregularly surfaced, with pair of low shiny swellings either side of middle, midline with similar low shiny swelling near base, sides of disc moderately depressed; pronotal punctures large but shallow, moderately close in depressed areas, where separated by 0.2–1.5 puncture diameters, sparse elsewhere; pronotum with sparse white hair-like recumbent setae, denser at sides, interspaces shiny, either shallowly microreticulate or without microreticulation; anterior angles prominently anterolaterally produced, 45–80°; anterior edge of pronotum slightly produced but usually concave at middle; lateral margins with one prominent median tubercle and a smaller tubercle (sometimes almost absent) between this and anterior angle, with remnant of lateral carina from this second tubercle to anterior angle; basal edge weakly convex and usually flat but with trace of beading medially in some specimens; hypomeron strongly punctured and sparsely pubescent, except hypomeral lobe rugose and glabrous; prosternum finely and densely punctured and pubescent; scutellum finely punctured and setose on basal third, apically shiny and impunctate; recumbent white elytral pubescence mostly sparse, but forming patches at sides of middle and along apical third of suture, this sutural patch laterally expanded anteriorly (approximately T-shaped when elytra combined), elytra also with sparse erect setae; elytral sculpture variable but always with small relatively evenly sized tubercles, although they may coalesce into short elongate ridges; at one extreme of variation, elytra dull and densely microsculptured, with irregularly scattered punctures and small round tubercles, and at the other extreme, elytra shiny, with shallow microsculpture only in depressed areas, punctures partly linear and tubercles forming elongate low ridges; elytral disc distinctly arcuately depressed in basal half posterior to humerus; elytral punctures large and deep, sparsely distributed, separated by 1.5–4 puncture diameters; discal elytral punctures with two small shining tubercles laterally on rim; elytral apices rounded; epipleuron impunctate and glabrous except line of recumbent white setae along basal margin; mesoventrite punctured as prosternum; metepisternum and metaventrite shiny, not or shallowly microsculptured, sparsely punctured and setose, with smooth impunctate midline; metatibiae with broad lateral longitudinal grooves, defining keels, short and robust and sparsely pubescent; bases of tarsomeres 1–3 depressed; protarsomeres 1–3 much broader at base (almost quadrate) in male than female.

Abdomen ( Figs 47 , 56, 57 , 66 , 73): ventrites I–V shiny, not or feebly microreticulate; I relatively sparsely but strongly punctured, interspaces much greater than puncture diameters; puncturation of II–V increasingly dense; ventrite V relatively densely and slightly rugosely punctured; ventrites with evenly spaced recumbent white setae, erect setae only present on apical margin of ventrite V; apex of ventrite V convex in both sexes; apex of penis abruptly contracted to mucronate tip in dorsal view, apex thick and short in lateral view; tegminal keel sinuate and shallowly convex in lateral view; female sternite VIII apodeme short and narrow, apical sclerotised area roughly triangular but expanded at sides, wider than long, apex shallowly concave; apex of gonocoxite without conspicuous setae; stylus elongate, length twice width, with median constriction; median ventral sclerite very short; spermatheca falcate, blunt tipped, with simple uncoiled duct.

Notes. The maxillary palpi of C. insignis were illustrated by Reid (1992; Fig. 20 ) under C. tuberosa .

Cheiloxena insignis seems to be endemic to south Victoria as there is a dense cluster of records in this area (material examined here and records in Reid 1992; Fig. 77 ). However, there is a single specimen from Mittagong, central New South Wales in the MVM collection ( Reid 1992). It is a typical specimen of the dull and microsculptured form of C. insignis . We think this is likely to be a mislabelled specimen, as all other material is from tall eucalypt forest within 200 km of Melbourne ( Fig. 77 ). Within this small area, C. insignis shows great variation in surface sculpture and it has been tempting to split this taxon into two species. Two morphological extremes are shown in Figures 7 and 8 , but note that the first is a fresh female specimen and the second is a worn male. Relatively dull specimens with non-linear elytral punctures predominate in the southern, lowland part of the range ( Fig. 7 ; Launching Place, at 100 m elevation), but Figure 8 is of a shiny specimen with partly linear elytral punctures and ridged intervals, collected at Lake Mountain, the northernmost part of the range, 42 km northeast of Launching Place and at 1300 m elevation (photographed live: Lagerwey 2016a). This male has a less mucronate penis ( Fig. 57 ) than a male of the dull form ( Fig. 56 ). There are morphological intermediates between the two forms, for example a specimen photographed near Launching Place (Lagerway 2016b), therefore we prefer to treat this as one variable species. Another live specimen has been photographed at Wonga Park, Victoria ( Lagerwey 2016b).

Despite being relatively frequently collected or observed in the Melbourne area, the host plants and biology of this species are unknown.

Figures

FIGURE 77. Eastern Australia showing distribution of Cheiloxena species.

FIGURES 7–10. Habitus of Cheiloxena species: 7, C. insignis Baly (Launching Place, Victoria); 8, C. insignis (Lake Mountain, Victoria); 9, C. monga Reid & Beatson (holotype); 10, C. tuberosa Reid; Not to scale.

FIGURES 13–21. Lateral of Cheiloxena species: 13, C. aitori Reid & Beatson, male (holotype); 14, C. blackburni Reid; 15, C. conani Reid & Beatson; 16, C. frenchae Blackburn, (holotype); 17, C. insignis Blackburn; 18, C. monga Reid & Beatson (holotype); 19, C. tuberosa Reid; 20, C. westwoodii Baly (northern form, Dorrigo); 21, C. westwoodii Baly (southern form, Victoria). Not to scale.

FIGURES 35–37. Cheiloxena species, ventral view: 35, C. insignis Baly, thoracic venter; 36, C. westwoodii Baly (Blundell's Range, ACT), male abdominal ventrites; 37, C. westwoodii (Island Bend, NSW), female abdominal ventrites.

FIGURES 38–42. Cheiloxena species: 38, C. tuberosa Reid, male antenna; 39, C. insignis Blackburn, male antenna; 40, C. insignis, metafemur; 41, C. tuberosa, pro- (left) and meta- (right) tarsi; 42, C. frenchae Blackburn, apex of tarsus.

FIGURES 43–51. Cheiloxena species, male genitalia lateral and dorsal: 43, C. aitori Reid & Beatson; 44, C. blackburni Reid; 45, C. conani Reid & Beatson; 46, C. frenchae Blackburn; 47, C. insignis Blackburn; 48, C. monga Reid & Beatson; 49, C. tuberosa Reid; 50, C. westwoodii Baly (northern form, Dorrigo); 51, C. westwoodii (southern form, Victoria). All images to scale, scale bar = 2mm.

FIGURES 52–61. Cheiloxena species, apex of penis: 52, C. aitori Reid & Beatson; 53, C. blackburni Reid; 54, C. conani Reid & Beatson; 55, C. frenchae Blackburn; 56, C. insignis Blackburn (Launching Place, Victoria); 57, C. insignis Blackburn (Lake Mountain, Victoria); 58, C. monga Reid & Beatson; 59, C. tuberosa Reid; 60, C. westwoodii Baly (northern form, Dorrigo); 61, C. westwoodii (southern form, Victoria). All images to same scale.

FIGURES 62–68. Cheiloxena species, female genitalia: 62, C. aitori Reid & Beatson; 63, C. blackburni Reid; 64, C. conani Reid & Beatson; 65, C. frenchae Blackburn; 66, C. insignis Blackburn; 67, C. tuberosa Reid; 68, C. westwoodii Baly (northern form, Dorrigo).