Corresponding author: Jesús Gómez-Zurita (
Academic editor: Michael Schmitt
The study of external morphology of the New Caledonian leaf beetle
Generic attributions of New Caledonian
Habitus of three species of
Size as a systematic criterion is liable to taxonomic confusion. In my initial steps to understand the systematic structure of New Caledonian
Type material: (1) Holotype, one male, La Foa,
Habitus of
Head large, deeply inserted into pronotum, nearly to upper eye margin; surface very delicately microreticulated; vertex weakly convex, very finely, rather densely and homogeneously punctured, with very fine median longitudinal impression, becoming progressively larger, on depressed longitudinal area on frons, joined apically to transversally widely obtuse fronto-clypeal suture. Clypeus wider than long, subtrapezoidal, depressed apically, with deep median semicircular apical emargination, flanked laterally by shortly produced denticles; surface microreticulated, with larger, deeper punctures than those on vertex, bearing minute, very fine setae anteriorly. Labrum as long as wide; surface finely microreticulated; sides feebly convergent towards round anterior angles; apex depressed and weakly emarginated; anterior angles with one pair of nearly adjacent fine golden setae; two setae anteriorly on disc. Genae very short, with some fine setae below eye margin. Eyes very big, dorsoventrally elongated; deeply emarginated at inner border for antennal insertion; supraocular margin furrowed, furrow not surpassing eye margin above, with long, yellowish dorsal seta. Space for antennal insertion concave, slightly raised dorsally above clypeus level; microreticulated, unpunctured, with one anterior, oblique fine golden seta. Antennae long and slender, reaching basal third of elytra; scape long, weakly flattened and arched antero-posteriorly; second antennomere elongated, slightly clavate, weakly curved, 0.66x as long as first; third segment straight, as long as second; antennomeres 4–5 subcylindrical, slightly shorter than scape, narrow and slender; 6–10 as long as scape, slightly widened towards apex, densely setose; apical antennomere longest, sharply pointed and paler at apex. Maxillary palpi short, slender; apical palpomere elongated, subconical.
Pronotum transverse, 0.58× as long as wide between posterior angles, shorter than head, transversally convex, especially at anterior angles; posterior border weakly bisinuated with weakly projecting median lobe, finely margined with premarginal line of dense dot-like impressions; posterior angles laterally projecting as small teeth continuing basal margin, with large apical setigerous pore; anterior border nearly straight, finely margined at sides, with margin broader and more imprecisely defined at middle; anterior angles laterally and slightly obliquely projecting as small teeth with large setigerous pore at apex; sides broadly curved, wider behind middle; lateral margins relatively wide, flat, glossy, with internal row of dense round impressions; pronotal surface delicately microreticulated, rather uniformly and densely covered by shallow, moderate punctures, smaller, almost disappearing near borders. Anterior border of hypomeron more or less straight, regularly continuing profile of anterior border of pronotum with that of prosternum, both remaining largely separated by anterior margin of hypomeron (see Fig. 4f in
Scutellum as long as broad at base, sides straight, weakly divergent at basal 2/3, curved at obtuse angle to obtusely pointed apex; surface finely alutaceous, unpunctured. Elytra slightly broader than base of pronotum; humeri round, slightly callose; sides very feebly curved, with maximum width behind middle, and regularly curved to broadly round apex; margins feebly explanate, entirely visible from above; surface shiny, with dense unordered minute punctures and regular series of strong punctures separated at most by distance equal to their diameter; short scutellar striae of some 14 punctures starting before middle of scutellum and obliquely directed to suture; sutural striae reaching from base of elytra to sutural angles, joining marginal striae at inner edge of explanate margin of elytra; four longitudinal discal striae from base of elytra joining successively to apical ends of ninth, eighth, seventh and sixth striae on preapical declivity of elytra; basal ends of striae 6–8 behind humeri and of premarginal stria 9 behind middle of elytra; short premarginal posthumeral striae, curved and convergent with elytral margin before middle of elytra; space between striae 7 and 8, medially and at lateral declivity of elytra occupied by two additional shorter longitudinal striae convergent at both ends; darkened sutural interval, humeri, elongated spots medially on disc on third interval and more advanced at lateral declivity of elytra on seventh interval between stria 7 and internal row of additional posthumeral striae. Epipleura flat, unpunctured, shiny, broad basally and gradually narrowing toward apex; only visible laterally below humeri. Species fully winged.
Profemora spindle-shaped at basal 3/4, nearly cylindrical at apical quarter; extremely finely alutaceous with scattered minute punctures and very short appressed setae on basal 3/4 and coarser punctures and longer setae at apical 1/4. Protibiae very slightly curved inward, gradually widened toward apex; with several fine longitudinal ridges and longitudinal series of semierect golden setae at intervals; apex concave, obliquely cut for tarsal insertion, densely setose internally. Protarsi 0.6× as long as protibiae; first tarsomere slightly expanded laterally, longer than wide at concave apex; second shorter than first, triangular with broadly concave apex; third deeply and narrowly bilobed; fifth longer than tarsomeres 2–3, slender, subparallel, ventrally curved; claws bifid, weakly divergent, long, sharp, with short, sharp inner teeth. Median and hind legs very similar to anterior legs, but tibiae straight, with conspicuous preapical emargination externally, margined by fringe of erect golden setae and apex not densely setose internally. Abdominal ventrites finely microsculptured, shiny, narrow, strongly transverse, with posterior border increasing concavity from ventrites one to four, finely but more or less uniformly punctured and with very fine, short whitish setae; sides corrugated; anterior process between metacoxae of first abdominal ventrite broader than long, regularly curved; last abdominal ventrite very feebly emarginated.
Median lobe of the aedeagus (
Male (
As it occurs with most
Distribution and diversity of
It is largely elusive understanding why such a diverse genus like
If differences in ability for dispersal compared to other eumolpines are not obvious, another possibility is that successfully colonizing
Yet another possibility is that ecological requirements for
A last possibility about the paucity of
The number of questions that this intriguing pattern suggest and the few, speculative answers available, highlight the importance of further research on New Caledonian fauna, from biodiversity and ecological surveys to phylogenetic analyses which will help understanding the history of colonization and diversification on this remote biodiversity hotspot.
During the course of this study, several homonyms were detected affecting the genus
I express my gratitude to Pierre Jolivet (Museum Nationale d’Histoire Naturelle, Paris), Ottó Merkl (Magyar Természettudományi Múzeum, Budapest), Max Barclay and Beulah Garner (Natural History Museum, London), and Matthias Schöller (Berlin) for kindly allowing me to study the