Altica Geoffroy 1762 : 244

Reid, C. A. M. & Beatson, M., 2015, Disentangling a taxonomic nightmare: a revision of the Australian, Indomalayan and Pacific species of Altica Geoffroy, 1762 (Coleoptera: Chrysomelidae: Galerucinae), Zootaxa 3918 (4), pp. 503-551 : 510-512

Altica Geoffroy 1762: 244

Type species. Chrysomela oleracea Linneus, 1758 , by subsequent designation ( Latreille 1810; Riley, Clark & Seeno 2003; Döberl 2010a).

= Haltica Illiger 1807: 59 (unjustified emendation of Altica : ICZN 1994)

= Graptodera Chevrolat 1836: 388 .

Type species: Chrysomela oleracea L., 1758, by subsequent designation ( Chevrolat 1845; Bousquet & Bouchard 2013).

Authorship of Altica is attributed to Geoffroy, not Müller (Opinion 1754, ICZN 1994). The complete generic synonymy of Altica is listed by Riley, Clark & Seeno (2003) and Döberl (2010a), but only two secondary synonymic names have been used in the Australian region as noted above: one invalid, the other an objective synonym.

Generic diagnosis. The following diagnostic description is based on the Australian, Indomalayan and Pacific species.

Moderately large amongst regional alticine genera, length 4.2–7.3 mm. Black (legs may be entirely red or reddish in teneral specimens, and one mature specimen of A. aenea ), dorsal surface with metallic blue, purple, green, coppery or bronze hues (sometimes without metallic reflection in A. corrusca & A. gravida ), venter and legs less strongly metallic; antennae varying from entirely dark to basal segments orange to red; mandibles with apical band of reddish-orange to dark brown. Body elongate-ovate, length 2–2.5x width; elytra rounded at sides, width at humeri 1.5–1.6x width pronotum and c. 1.8x width head. Dorsal puncturation generally sparse and shallow, interspaces >> puncture diameters. Dorsum mostly glabrous, except patches of short setae present at sides and anterior of head, a pair of trichobothria at anterior of vertex, and a trichobothrium at each corner of pronotum; elytra with minute setae, adpressed to surface, only visible at high magnification. Prothoracic venter mostly glabrous, with setae at posterior edge of prosternum and prosternal process; mesoventrite process glabrous, but remainder of mesothoracic venter, metathoracic venter, abdomen and legs almost entirely densely pubescent.

Head. Face with slightly convex profile; eyes laterally prominent, with straight or feebly concave inner margins; minute inter-ommatidial setae present; vertex smooth, without median groove, but often with small medial swelling at posterior of postantennal calli; sulci at upper margins of calli and posterior part of orbit absent or shallow but posterior margin of orbit abruptly elevated; orbit broad and convex between eye and postantennal calli, as wide or almost as wide as antennal socket, tapering in width to gena; frons with pair of well-defined large and triangular to quadrangular postantennal calli which almost touch posteriorly; frontoclypeal median ridge prominent, separating calli at base and extending anteriorly to elevated clypeal anterior margin; lateral margins of frontoclypeal area, anterior to antennal sockets, not elevated; interantennal space 0.8–1.5x socket diameters, sockets approximately level with middle of eyes and separated from them by 0.5– 1 x socket diameters, antennal fossa separated from calli and antennal sockets by a punctate groove or depression; posteriorly not defined by a groove, anteriorly not extending to interantennal space; antennae 11-segmented, length 0.5– 1 x body length; all antennomeres elongate, 1 ≤ 2x length 2, 2 shortest, ovoid, 3 much longer than 2, 4 usually equal longest with 11; labrum with 2–5 pairs of discal setae, distribution often asymmetric, apical margin truncate to slightly concave; mandible with three apical teeth and angulate internal margin; apical maxillary palpomere conical, as long as but narrower than preapical; gena 0.1–0.2x eye length, with or without transverse setose ridge between eye and buccal cavity.

Thorax. Prothorax distinctly broader than head and much narrower than elytra (c.0.7x width elytra at humeri), broadest at base or middle; sides of pronotum slightly convex; anterior and sides of pronotal disc often shallowly depressed or dimpled, sometimes asymmetrically; arcuate patch of deep glandular punctures clustered near anterior angles, with most punctures on anterior part of arc; pronotum transversely depressed anterior to basal margin, the depression sinuous, usually sharply defined and almost reaching lateral margins where it merges with narrow lateral explanation; area betweeen transverse groove and basal margin (basal field), usually sculptured differently from pronotal disc; pronotum without two short longitudinal grooves cutting across basal field, but sometimes shallowly depressed between transverse depression and basal margin; anterior and posterior angles each with trichobothrium, anterior angles rounded, slightly swollen (pronotal callus) with setae preapically inserted on callus, posterior angles 90° or slightly projecting laterally; pronotum with distinct raised border present basally and laterally, but absent anteriorly; hypomeron without groove near lateral margin; prosternal process slightly convex, elongate, slightly expanded at tip, transversely grooved at base; procoxal cavities broadly open, gap as long as hypomeral process or wider; scutellum triangular to semi-ovate; elytra convex in cross-section, covering abdomen, subparallel or slightly expanded from humeri to <2/3 length, non-striate, without transverse posthumeral depression; epipleuron distinct, entirely laterally visible, gradually narrowed from base to apex, with upper margin continuous to elytral apex; fully winged, wing with single vein in medial field, leading off elongate basal cell; mesoventrite not covered by metaventrite, with paired cavities at anterior edge (procoxal rests); mesoventrite process exposed, quadrate to elongate, apex bilobed, surface usually longitudinally ridged; metendosternite with triangular basal stalk (apical angle about 70°) and thin arms with unlobed apices; mid coxae separated by much less than width of coxa; pro- and mesofemora almost parallel-sided, metafemur larger, greatest width c. 1.2x width mesofemur, dorsal margin evenly convex, ventral margin almost straight; metafemoral endosclerite large, almost half length metatibia, with basal stalk at least as long as tightly coiled spring; tibiae without apical excavation on outer edge; anterior tibia expanded to apex, more so in male; metatibia not prolonged beyond tarsal insertion (insertion apical), without rows of spines; each tibia of both sexes with one small simple apical spur, inserted on inner side of apex, spur half apical tibial width or less; length hind tarsus c. 0.7x length hind tibia; first hind tarsomere slightly shorter than 2+3; third tarsomere deeply bilobed; apical metatarsomere not arched or inflated; tarsal claws appendiculate, appendage right-angled, or almost so, and shorter than half claw length. Abdomen. Pygidium rounded at apex, without longitudinal median sharp-edged groove; abdominal ventrites free, not fused; surface ventrite I evenly convex, without median ridges; ventrites II–IV not laterally bordered or keeled; male ventrite V of male with median flat convexly margined lobe; apex female ventrite V evenly convex; penis symmetrical, apex entire, base without recurved lobes; endophallus with two long strongly sclerotised rods, in basal half of penis in repose; tegmen Y-shaped; ovipositor with well-developed strongly sclerotised but thin rodlike tignum on mostly membranous sternite 8; vaginal palpi one-segmented, with internal apodeme as long as or longer than everted portion of palp; spermathecal receptaculum C-shaped, collum U-shaped, with base of ‘U’ slightly kinked to strongly convoluted, insertion point of spermathecal gland swollen as a round or transversely ovate appendage to base of collum.

Notes. Altica is easily recognised in the regional fauna by the diagnostic characters listed above, especially colour, procoxal cavities, ventral pubescence, thoracic sculpture, elytral sculpture and leg morphology. The structurally most similar genera are: Agasicles , in which the single species (exotic) in this region is striped black and yellow; and Sutrea , which has strongly expanded hind femora, lacks a well-defined pronotal transverse groove, and has the hind tibial spur inserted outside the base of the tarsus. In Australia, Sutrea species are never uniformly metallic.

The features used by many authors to discriminate species of Altica were reviewed by Kangas & Rutenen (1993), following Kevan (1962) and others. They included: colour, puncturation, microreticulation, facial sculpture, mandibles, elytral sculpture, relative size of tarsomeres, penis, vaginal palpi, spiculum ventrale, spermatheca. The authors found each to be of limited use, as none was comprehensively diagnostic for the 12 species in Finland. The authors also found occasional abnormal specimens which defied identification from external characters. The most recent review of Altica morphology ( Döberl 2010b) has added new characters: development of the pronotal groove, shape of external face of tibia, and structure of the apical lobe of male ventrite V (named the hemicyclus by Döberl).

The characters listed by Kangas & Rutanen (1993) and Döberl (2010b) were applied to the Australian and regional specimens, as well as a few other characters based on the experience of CAMR with galerucine genera (for example, Reid 1988, 2003; Reid & Nally 2008). A limited range of dorsal colours was shown by the six Altica species studied, with a predominant hue in each, but some variation present. For example, 59 of 76 A. corrusca examined were dark blue, but 11 were dark green, 3 dark purple, 2 bicoloured with blue anterior and green elytra, and one bicoloured asymmetrically with one elytron green and one dark purple. The colour of the first antennomere was useful: all examined mature specimens of A. caerulea , A. corrusca and A. gravida had the first antennomere black or with at most a small red apical spot, all specimens of A. aenea had at least the apical quarter of the antennomere dark red to orange; but in A. cyanea both colour states were present. Eye size and head width were useful (Tables 3–4). Facial sculpture provided some useful information, particularly the development of the postantennal calli, median longitudinal carina and anterior clypeal ridge, but it was difficult to define accurately, and was intraspecifically variable. Antennomere shapes and ratios were not significant; all the Altica species typically had antennomere 4 longer than 3, and 3 longer than 2, but with rare anomalous specimens (for example, one specimen out of 30 A. corrusca examined showing antennomere 3 slightly longer than 4). The number of labral setae was frequently asymmetric and not useful. The labral tormae in single specimens of each Altica species showed differences but were also asymmetric therefore we suspect this character is variable ( Figs 15–18). The mandibles of single specimens of each Altica species were virtually identical. Puncturation of the Altica species was found to be interspecifically similar and intraspecifically variable, with each species showing a wide range of puncture sizes and densities. Microsculpture on the dorsal surface was an important discriminant for A. caerulea and A. gravida . The presence or absence of a longitudinal fold on the elytra was not universal within a species, difficult to characterise, and variable in strength (including some specimens with multiple longitudinal folds). The degree of convexity of the external surface of the mid tibia was useful, although difficult to define. Relative length of tarsomeres was almost constant. The male ventrite V apical lobe (hemicyclus) showed no obvious interspecific variation, in contrast to African species ( Döberl 2010b) and was generally hard to see, being obscured by setae. The shape of the vaginal palpi provided discrimination of the species into two groups. Primary sexual characters were most useful as species discriminants, but the spermatheca was too variable for species diagnosis. The best character for discriminating males was the shape and surface sculpture of the penis. The best character for discriminating females was the shape of the tignum.