Bohumiljania Monrós, 1958

Reid, C. A. M. & Beatson, M., 2011, Revision of the New Caledonian endemic genus Bohumiljania Monrós (Coleoptera: Chrysomelidae: Spilopyrinae), Zootaxa 3000, pp. 1-43 : 3-6

Bohumiljania Monrós, 1958

Bohumiljania Monrós, 1958: 149 ; Seeno & Wilcox 1982: 50; Jerez 1996: 256; Reid 2000: 856; Verma & Jolivet 2002: 99; Jolivet, Verma & Mille 2003: 3; Verma & Jolivet 2004: 395; Jolivet, Verma & Mille 2005: 63; Verma & Jolivet 2006: 297; Jolivet & Verma 2008a: 14; Jolivet & Verma 2008b: 313; Jolivet & Verma 2010: 56; Reid & Beatson 2010a: 8.

Type species: Bohumiljania antiqua Monrós , by original designation and monotypy

Diagnosis

This diagnosis of Bohumiljania replaces that provided earlier ( Reid 2000), which was based on examination of only one species, plus the type species description ( Monrós 1958). However, our treatment of Bohumiljania in a recent key to genera of Spilopyrinae was based on examination of most of the material available below and is valid ( Reid & Beatson 2010a).

Length 8–23mm; shape elongate, almost parallel-sided but base of pronotum distinctly narrower than width of elytra at humeri; antennae gracile, all antennomeres elongate, 7th comparatively swollen; upper surface without tubercles; pronotum laterally margined or at least partly so; prosternal process elongate and elevated between coxae, almost parallel-sided, with deeply bilobed apex; elytra without transverse grooves; epipleural upper margin abruptly raised at humerus; mesosternal process elevated, with convex base and deeply bilobed apex; tibial spurs 1+2+2; claws simple, with at most slight angulation at base of ventral margin; ventrites 1 and 2 fused; female median sclerite present in ovipositor; rectal kotpresse present.

Description [based on males of 4 species and females of 8]

Length 8–23mm, females distinctly larger than males, lengths not overlapping within species; body ( Figs 5–12) elongate-ovate, length 2.5–3.3x width, with elytra approximately parallel-sided from humeri to apical third, at humeri much broader than pronotum at base; profile mostly flat to weakly convex, length 2.6–4x height. Dorsum usually non-metallic green, yellow or brown, rarely with bronze reflection ( B. yuaga sp. nov.), glabrous to densely setose, trichobothria adjacent to eyes and on each corner of pronotum.

Head ( Figs 13–36): clypeus delimited by sutures, smooth, triangular, usually depressed at base of sutures, anterior margin shallowly concave, not elevated; frons and vertex smooth, depressed on midline, rarely with irregular pitting between midline and eye; eyes ovate, height 1.3–1.5x width, inner margin shallowly concave; eye laterally projecting, posterior curvature contiguous with short temples (<1/5 length eye), which are constricted to parallelsided rear of head capsule, or temples narrowly swollen and posteriorly truncated ( B. yuaga ); shortest length gena 0.1–0.4x greatest eye length; genal lobe ratio 1.2–2; antennae situated at anterior of head, 4–5x socket diameters apart, sockets laterally directed; gular region quadrate, glabrous, impunctate and transversely grooved posterior to deflected lip of buccal cavity; antennae 0.5–0.75x body length (longest in males, shortest in females); relative sizes of antennomeres variable, but 1 always enlarged cylindrical or widest at apex, 2 shortest (0.5–0.67x first), antennomeres 8–11 almost parallel-sided, 11 longest, 7 slightly broader than 2–11; antennomeres 1–6 shining and sparsely punctured, 7–11 dull and densely microsculptured; labrum not densely setose, with 1–3 pairs of dorsal setae; each mandible with two broad apical teeth and outer concavity bounded by a low ridge; apical maxillary palpomere elongate, fusiform to cylindrical, males with broader apex; preapical palpomere triangular, length equal to or shorter than apical, of similar width; mentum either transversely rectangular, width c. 2x median length, without prominent anterior angles, or more strongly transverse, width 3x median length, with prominent anterior angles.

Thorax ( Figs 5–12, 37–85): pronotum transverse, width 1.15–1.3x length, broadest at or posterior to middle, not or weakly contracted to posterior angles; disc with pair of laterobasal elongate grooves or depressions, which may be feebly indicated; anterior edge truncate to concave, middle of posterior with broad convex lobe; anterior not margined at middle, posterior (at least at sides) distinctly margined, lateral margination present, complete except one rugose species ( B. xaracuu sp. nov.); anterior angles laterally prominent; posterior angles in same vertical plane as posterior margin of hypomeron; posterior edge of pronotum locking into hollowed base of elytra; prosternum elongate and punctate between coxae and head; prosternal process elongate, elevated and flat or medially grooved, with strongly bilobed apex; procoxal cavities closed by insertion of hypomeral lobes into prosternal process; scutellum quadrate to semi-oval, sides superimposed on sutural base; elytra approximately parallel-sided for basal 2/3, with distinct humeri, without distinct lateral or median depressions except small area between humerus and epipleuron in some species; elytral punctures confused, non-striate; elytral epipleuron abruptly raised at base to humerus, otherwise narrow, width <0.2x elytral width, entirely visible laterally and not or feebly sinuate, with apex obscured by loss of dorsal margin; mesoventrite covered medially in repose by apex of prosternal process, sides densely punctured and pubescent, process almost glabrous, elevated and parallel-sided, with bilobed apex; mesanepisternum and mesepimeron densely punctured and pubescent; wings fully developed, medial field with two enclosed cells and 4 apical veins reaching wing margin, patch of dense microspicules (medial fleck) between apex of vein MP 3 and medial spur, which may be coloured; metaventrite transverse, width 1.3x length, smooth and shining at middle, transversely wrinkled and densely setose at sides, without femoral plates; metepisternum densely and finely punctured and pubescent; all femora fusiform, with base and apex narrowed, without longitudinal keels or ridges; all tibiae round in section, without keels, thin, with slightly expanded apices; one short apical spur on protibia, two on remaining tibiae; all first tarsomeres with ventral oval patch of modified setae in males, with dense simple setae diverging from midline in females; apical margin second tarsomere concave; third tarsomere deeply bilobed, lobes at least 0.65x length; apex fifth tarsomere with thin blade-like ventral lobe; claws simple, without basal tooth.

Abdomen ( Figs 86–148): pygidium (tergite 7) not strongly sclerotised except at apex, basal half membranous, apical half pubescent and punctured, without median groove; ventrite I with triangular intercoxal process and without femoral plates; ventrites I and II completely fused; ventrite V smooth, not medially depressed, apex concave, truncate, or convex; male sternite VIII transverse-rectangular, weakly sclerotised, without basal spiculum or with short asymmetric spiculum ( B. mandjelia sp. nov.); sternite IX of male Y-shaped; male tegmen present, almost enclosing penis, U-shaped, thinly sclerotised and with distinct internal median basal keel; penis simple, flattened tubular, apex sparsely microspiculate, basal foramen 0.4–0.6x length of penis; endophallus with strongly sclerotised flagellum, not exerted in repose; vas deferens with long thickened sperm pump and valve; female tergite VIII well-developed, sternite VIII with transverse to elongate basal apodeme; ovipositor with thin bacillus wrapped around bases of paraprocts, which are well-developed, partly enclosing basal half of palpi, pair of well-defined elongate proctigers dorsal to these; vaginal palpi 2-segmented, gonocoxite massive, not divided, stylus ovoid to flattened and freely articulated or almost fused to gonocoxite; membranous pad between gonocoxites with elongate median sclerite; spermatheca variable in shape, surface microreticulate, with short and thick unspiralled spermathecal duct, which may be secondarily thickened near junction of spermathecal gland; kotpresse present, venter of rectum with dense elongate patch of spinules, dorsum with narrow strips or band of spinules.

Immature stages

Eggs have not been described, but are illustrated by Jolivet & Verma (2009, plate 39).

There are brief descriptions of the larvae of two species, with photographs of live specimens ( Jolivet et al. 2003, 2005). The first-instar only has meso- and metathoracic eggbursters ( Jolivet et al. 2003), like Macrolema ( Reid & Beatson 2010a) . The following description is based on a late instar larva of B. lafoa sp. nov. ( Figs 149–152), kindly supplied by our colleagues Pierre Jolivet and John Lawrence.

Head capsule circular, shallowly strigose except smooth anterior and sides; setae simply pointed, short and inconspicuous, mostly minute; posterior margin of head capsule evenly rounded; coronal suture short and endocarina entire length of elongate dorsal segment of frons; frons transversely divided by suture into upper and lower halves, upper half elongate-triangular, lower transverse; frontoclypeal suture absent, clypeus not distinguishable; 6 stemmata, arranged 4+2, latter ventral, at edge of buccal cavity; antenna apparently 2-segmented, 3 rd segment present but minute; labrum small, apex biconvex with small median tooth, separated from clypeus by suture but not freely articulated; mandibles lacking mola and penicillus, with 4 teeth, first minute, on inner face, second and third large and acute, fourth large and truncate; maxillary palp 3-segmented, on basal palpifer; labial palp 2-segmented, surrounded by narrow U-shaped prementum and U-shaped mentum, with trace of basal submentum. Body segments demarcated and dorsally subdivided by deep folds, laterally swollen in epipleural region, generally without evident sclerites, except: sclerite on prothorax darkened and microspiculate at edges; weakly defined square sclerite in prosternal area; dark microspiculate dorso-lateral area on mesothorax and metathorax; dark microreticulate lateral swelling on abdominal segments 1–7; two dark sclerites at base of each leg. Dorsum of segment 8 (and possibly part of 7) thickened as a circular plate with long fringing setae and longitudinal median split, overlapping short dorsal sclerotised plate of segment 9; venter of abdominal segments 9 and 10 surrounding T-shaped anus. Spiracles free, annular, above lateral swellings, decreasing in size from mesothorax to abdominal segment 7, but large and ventral on segment 8. Dorsum of abdominal segments without everted soft integument. Venter of abdominal segments 2–5 with transverse soft swellings (possibly ambulatory ampullae). Leg segments at least partly darkened: trochanter and femur broadly fused at ventral junction; tibiotarsus strongly elongate, venter soft, transparent and apically swollen (paronychial appendix); claw short, third length of tibiotarsus, longer than deep and without lobe at base.

The pupa is unknown.

Notes

There is little obvious sexual dimorphism, except in size and tarsal setation. Males are remarkably 10–20% shorter than females with no overlap in size range (however, both sexes were only available for three species). Males also have proportionally larger eyes and longer antennae, but only slightly so in two of three species. The apex of the male last ventrite is at least blunter than the female, but not always of a different shape.

Colour seems to be diagnostic for most species considered here, although we only have small samples. It has been claimed that the green colour of Bohumiljania changes to brown in dried specimens ( Jolivet et al. 2003), like the ephemeral green of the spilopyrine Stenomela pallida Erichson, 1847 ( Jerez 1996) , but unlike the metallic greens of Macrolema and Spilopyra species ( Reid & Beatson 2010a, b). The green specimens examined here were collected up to 32 years ago, and none shows evidence of losing its characteristic green hues, although one specimen may have darkened. We suspect that Jolivet and co-authors, convinced that the green species at La Foa and the uniformly reddish-brown ( Monrós 1958) or black ( Jolivet et al. 2003) species described by Monrós are one and the same thing, have explained the colour difference by assuming that older specimens fade to brown.

Character variation within species was hard to assess, as multiples of both sexes were only available for two species, B. lafoa and B. xanthogramma sp. nov. These species are closely related, best distinguished on genitalic characters. The specimens of B. lafoa were particularly important as they came from a single population. Individuals showed significant variation in dorsal surface-sculpture ( Figs 37–38) and in the lateral keeling of the ventrites, the latter used as a diagnostic character in other spilopyrine genera ( Reid & Beatson 2010a, b). Relatively constant characters within these species include colour, length/breadth ratio, pubescence, puncture distribution, antennal structure, prothoracic angles, elytral epipleura and apices, male seventh abdominal sternite ( Figs 89–91, 93–95), penis ( Figs 102–104, 106–108) and spermatheca ( Figs 138–140, 143–144). This information provided the basis for recognition of species among the remaining specimens. However there were problems in determining two individuals (see under B. lafoa and B. xanthogramma ) and we acknowledge that this study is not the last word on the taxonomy of this fascinating genus. Furthermore, three species are based on single specimens. Clearly much more collecting is required.

The larval morphology is unique in the Spilopyrinae and requires redefinition of the subfamily and revision of the published key to subfamilies of Chrysomelidae ( Reid 2000) . In the key to larvae of chrysomelid subfamilies, couplet 14 should be altered to ‘usually 5 pairs of stemmata, rarely 6’ ( Reid 2000: 852). The thick circular apical abdominal plate with a setal fringe of Bohumiljania is found in Stenomela Erichson, 1847 ( Jerez 1996) and Macrolema Baly, 1861 ( Reid & Beatson 2010a), but in these two genera the plate is the result of fusion of the tergal parts of segments 8 and 9, is not medially divided and encloses dorsal spiracles.

Distribution & biology

Bohumiljania is endemic to the main island of New Caledonia. The species are mostly associated with rainforested elevated areas scattered along the island, including high elevation cloud forest, but one species occurs at a lowland site in the western plains ( Figs 153–155).

Most specimens have been collected at mercury vapour light, suggesting adults disperse at night. Peak activity seems to be in high rainfall months (December to February). The hostplants are all Myrtaceae : Metrosideros laurifolia , Myrtastrum rufopunctatum ( Jolivet et al. 2005) and Syzigium cumini ( Jolivet et al. 2003) , belonging to three different tribes of the family ( Wilson et al. 2005; Govaerts et al. 2008). Myrtaceae are a large and diverse family on New Caledonia (loc. cit.; Snow 2009). Syzigium cumini is an exotic species there, but more than 90 native species of Syzygium exist on the island, most of which belong to the same subgenus as S. cumini ( Craven & Biffin 2010) .

A little information is available on the life history of two species ( Jolivet et al. 2003, 2005). Eggs are laid in small clusters of 3–4 on leaf lamina and covered with a thick layer of faecal and glandular material. The first-instar may burrow into host tissue but later instars are free-living. Pupation is thought to be in soil.