Canobolas Reid, Jurado-Rivera & Beatson

Reid, Chris A. M., Jurado-Rivera, José A. & Beatson, Max, 2009, A new genus of Chrysomelinae from Australia (Coleoptera: Chrysomelidae), Zootaxa 2207, pp. 53-66 : 54-56

Canobolas Reid, Jurado-Rivera & Beatson , gen. nov.

Type species. Geomela nobilis Lea, 1917 , this designation.

Description (adult). Length 3.5–6.0mm; body ( Figs 1–8 ) almost circular to elongate-ovate, length 1.1–1.7x width, moderately to strongly convex in profile, length 1.7–2.4x height. Dorsum dark reddish-brown to black, with or without slight metallic green or blue reflections, glabrous except a few recumbent setae above antennal insertions.

Head ( Figs 4 , 8 , 9 , 11–14 ): fronto-clypeus smooth, without antero-lateral ridges and with an arcuate groove or shallow depression between (but not reaching) bases of antennae, which are adjacent to eyes; vertex obliquely grooved posteriorly from inner margin of each eye (groove often hidden by overlapping prothorax); eyes strongly transverse (narrow in dorsal view), height c. 3x width, partially ventral, inner margin shallowly concave; eye laterally projecting, anteriorly truncate and posteriorly abruptly constricted to parallel-sided head capsule, temples absent or almost so; antennae situated on anterior margin of head; venter of head with deep and smooth elongate subantennal groove, length c. 3x width, bounded by ridges, for retention of antenna between eye and mouth; antennae c. 0.3–0.6x body length, antennomere 1 enlarged, ovate, 2 short (half length of 1), 3 relatively narrow and elongated (length 2.5–3.5x width), 6 reduced, shorter than either 5 or 7, 7–10 expanded from base to apex, length 0.9–1.7x width; labrum not densely setose, with 3–5 pairs of prominent setae; mandible with two apical teeth and thick membranous pad (pulvillus) near middle of inner margin; apical maxillary palpomere elongate, cylindrical or fusiform, preapical palpomere triangular, shorter than apical and of similar width; first maxillary palpomere without groove or ridge to receive second palpomere; mentum transverse, width c. 3x median length, but anterior angles narrowly produced.

Thorax ( Figs 1–9 , 15–18 ): pronotum transverse, broadest at base, evenly convex in cross section or with feeble lateral depressions; anterior edge concave, posterior convex and lateral edges slightly convex; anterior and sides distinctly margined, base without margination; anterior angles rounded, posterior angles approximately 90°; pronotum without trichobothria, angles non-setose; hypomeron impunctate, without groove; prosternum with strong oblique ridge anterior to each coxa, for retention of antennae; prosternal process about as broad as long, or slightly broader, truncate, evenly expanded to apex, with lateral ridges converging anteriorly at or just before anterior margin of prosternum; procoxal cavities open, gap at least half width of procoxa; scutellum with rounded apex; elytra evenly convex, without basal or lateral depressions, with scutellary striole and 8 complete regular striae, 9th present at least in basal third, 10th present as series of large punctures above epipleural margin; elytral epipleuron narrow, width <0.2x elytral width, entirely visible laterally, slightly sinuate, gradually contracted from base to apex, and without setae; anterior elytral wingbinding patch on oval swelling one third from base; mesoventrite visible between prosternal process and metaventrite, medially reduced to short strongly transverse (width> 3x length) median process, with shallowly concave apex, and laterally reduced to a thin arcuate ridge between each mesocoxa and prosternal process; anterior of mesoventrite process abruptly declivous to accommodate prosternal process; wings entirely absent; metaventrite evenly microreticulate, strongly transverse, width 3– 4 x length, with deep median depression and anterolateral margins flattened and expanded as smooth areas (femoral plates); metepisternum smooth, not longitudinally grooved; metendosternite with short basal stalk and thin recurved lobes at apices of lateral arms; all femora flattened, slightly fusiform to almost parallel-sided, ventral surfaces defined by paired longitudinal ridges; all tibiae flattened, with one dorsal and two ventral keels, expanded from narrow base to beyond middle, then dorsally excavate before apex to accommodate first tarsomere; all first tarsomeres with ovate patch of spatulate setae in males, with dense non-spatulate setae diverging from midline in females; apex of third tarsomere shallowly concave; claws simple, without basal tooth.

Abdomen ( Figs 3 , 10 , 15–24 ): pygidium deeply grooved from base to apex along midline, groove rectangular in cross-section, gradually narrowed from base to apex; tergite VIII with distinct spiracles; ventrites free, not fused, ventral surfaces of I and V laterally bound by elevated ridges; ventrite I with intercoxal process truncate at apex, anterior border flattened and expanded behind coxae (femoral plates); ventrite V smooth, not medially depressed, and truncate at apex in both sexes, but male with transverse rectangular internal flange; sternite IX of male reduced to two separate struts; male tegmen present, V-shaped; penis simple, flattened tubular, with small basal foramen, <0.3x length of penis; base of penis with longitudinal split; female tergite 8 well-developed, sternite 8 with long, thin, basal apodeme ( C. nobilis ) or with short bifurcate apodeme ( C. jarrah ); ovipositor with pair of well-developed paraprocts, partly enclosing basal half of palpi, and pair of weakly sclerotised and poorly defined elongate proctigers dorsal to these; vaginal palpi 2-segmented, second segment large and elongate; spermatheca falciform, with long coiled spermathecal duct which is expanded at attachment to bursa copulatrix.

Distribution and biology. Canobolas is endemic to Australia ( Fig. 25), where it occurs in the South-west, Southeastern New South Wales and McPherson-Macleay bioregions (Crisp et al. 1999). Western localities are low altitude (<500m), dominated by closed eucalypt forest, whereas eastern localities are high altitude (at least> 800m, probably> 1100m), in subalpine woodland ( Fig. 26 ). Each species is known from only one or two localities.

No beetles have been observed feeding on plants. DNA data from plant fragments in a specimen of Canobolas nobilis suggest that the species is polyphagous (see under species description below). Immature stages are unknown.

Etymology. The genus is named from the massif of Mount Canobolas , where the type species was collected. Canobolas means 'two shoulders' in the local Wiradjuri language ( Anonymous 2003). The name is arbitrarily designated masculine.

Systematics. The new genus is most similar to the endemic Australian genera Cyclonoda Baly , Ethomela Lea , Eugastromela Lea , Geomela Lea , Gibbiomela Daccordi and Palaeomela Daccordi ( Reid 2006a) . It shares with them: body relatively small and ovoid; colour black or almost so, often with slightly metallic blue or green reflection; eyes laterally produced; trichobothria absent from each corner of pronotum. Gibbiomela and Palaeomela are easily distinguished from Canobolas : the former by the extremely narrow prosternal and mesoventrite processes and absence of subantennal grooves; the latter by closed procoxal cavities, absence of femoral plates, bilobed third tarsomeres and pygidium without median groove. Eugastromela is also easily distinguished, by its deeply grooved facial sutures, lack of antenna-retaining ridges and grooves on head and prosternum, tuberculate elytra, absent femoral plates, bilobed third tarsomeres and penis without basal split. The remaining genera, Cyclonoda , Ethomela and Geomela , are more similar in size and shape to Canobolas .

Geomela and Ethomela are distinguished from Canobolas by: mesoventrite process not abruptly raised, less transverse (width <2x length), with anterior margin not excavated to retain truncate apex of prosternal process; apex third tarsomere bilobed; apex last ventrite in male without rectangular internal flange; tegmen absent. Furthermore Ethomela has closed procoxal cavities and the tibiae of Geomela are not externally keeled.

Cyclonoda is distinguished from Canobolas by: male clypeus asymmetrically lobed; groove absent above eye; last maxillary palpomere elongate-cylindrical and truncate; elytral epipleura strongly sinuate, abruptly attenuate in apical third; metaventrite and first abdominal ventrite without femoral plates; pygidium without median groove; vaginal palpi 1-segmented.

On these criteria Canobolas is a distinct monophyletic group of species, possibly the sistergroup of Cyclonoda .

Figures

FIGURE 26. Snowgum (Eucalyptus pauciflora) woodland, 1380 m, Mount Canobolas, New South Wales; habitat of Canobolas nobilis (Lea). Photographed 2 November 2006, José Jurado-Rivera.

FIGURES 1 – 4. Canobolas nobilis (Lea), male: 1, dorsal; 2, lateral; 3, ventral; 4, face.

FIGURES 5 – 8. Canobolas species, dorsal: 5, C. jarrah sp. nov.; 6, C. minang sp. nov.; 7, C. tubrabucca sp. nov.; face: 8, C. jarrah sp. nov.

FIGURES 9 – 10. Canobolas nobilis (Lea): 9, venter of head and pronotum; 10, venter of ovipositor.

FIGURES 11 – 14. Canobolas species, male antenna (drawn to scale): 11, C. jarrah sp. nov.; 12, C. minang sp. nov.; 13, C. nobilis (Lea); 14, C. tubrabucca sp. nov.

FIGURES 15 – 18. Canobolas species, partial right side of venter, showing metaventrite, metacoxa and first abdominal ventrite, femoral plates shaded (drawn to scale): 15, C. jarrah sp. nov.; 16, C. minang sp. nov.; 17, C. nobilis (Lea); 18, C. tubrabucca sp. nov.