Stoiba Spaeth, 1909: 720

Shin, Chulwoo & Chaboo, Caroline S., 2012, A revision and phylogenetic analysis of Stoiba Spaeth 1909 (Coleoptera, Chrysomelidae), ZooKeys 224, pp. 1-36 : 4-7

Stoiba Spaeth, 1909: 720

Stoiba flavicollis [type species as originally designated], 1914: 51 [catalog]; Hincks 1952: 335 [checklist]; Jolivet 1959: 83 [locality with wing figure]; Seeno and Wilcox 1982: 174 [checklist]; Jolivet and Hawkeswood 1995: 158 [microptery]; Borowiec 1999: 130 [catalog]; Chaboo 2000: 379 [outgroup in phylogenetic analysis]; Jolivet and Verma 2002: 64 [microptery]; Chaboo 2007: 184 [phylogeny]; Borowiec and Świętojańska 2012 [online catalog].

Diagnosis.

Stoiba differs from most of mesomphaliine genera by pale antennal color (except for Stoiba bruneri with 11th antennal segment black)and from Elytragona by the quadrate basal tooth of claws, rounded basal line of pronotum, separate elytral suture, moderately and distinctly convex profile, and fully-developed or brachypterous hind wing.

Description.

Body (Figs 11-40) generally rounded to oval with pronotum and elytra slightly to distinctly discontinuous in dorsal view, hemispherical in lateral view, widest and highest between basal 1/3 and middle of elytra.

Head (Figs 44-46) concealed by prothorax except for half of eyes and inter-ocular region in dorsal view,rounded to subquadrate (in disarticulate specimen), widest at middle, 1.25 times as broad as long; gena and eye well exposed in lateral view. Eyes large, oval, bulging, located on upper antero-lateral region of head; inter-ocular area twice as broad as eye diameter, slightly depressed or flat with antennal sockets and mid-cranial suture. Frontoclypeus (Fig. 45) broad and rounded pentagonal, rarely subquadrate with surface flat to slightly swollen (individual variation), sparsely setose; ventral angle slightly arched with frontoclypeal suture. Antenna 11-segmented (Figs 47-56), longer than lateral edge of pronotum; interantennal region as broad as antennal socket or slightly narrower; scape twice as long as broad, over 2 times longer than pedicel; pedicel as long as broad or slight longer; antennomeres III–IV slender, shiny, parallel to slightly broader apically, sparsely setose; antennomeres V–VII pale, pubescent, slightly longer or as long as broad; antennomeres VIII–X pale, as long as broad or slightly broader, pubescent setose with fine long setae on sub-apical region; antennomere IX as long as scape or slightly longer, twice longer than width, densely setose with long setae on sub-apex.

Mouth fossa (Fig. 46) rounded subquadrate with upper half broader and well-sclerotized. Labrum (Fig. 57) with basal half withdrawn into frons; anterior half shifted ventrally, sparsely punctate with long setae, broadest at shifted line with anterior edge well-sclerotized and medially emarginate. Mandible (Figs 58-59) well-sclerotized, fist-shaped with 4-5 teeth or 4 teeth with a vestigial projection ventrally; apical half shifted toward mouth fossa; basal half punctate and setose. Maxilla (Figs 60-61) long and slender; cardo long, medially narrower; stipes weakly sclerotized, irregularly triangular with short and fine setose medially; lacinia small, membranous, petal-shaped with basal region more sclerotized, densely setose; galea irregularly oval, setose with apical half more sclerotized than basal half; maxillary palpus 4-segmented with palpifer laterally connected to stipes; palpomere I shortest, triangular; II over 2 times longer than I, broader apically, slightly curved; III shorter than II and IV, broader apically with long setae on sub-apex; IV about 1.5 times as long as III, setose with apex flat and with sensilla structure. Labium (Figs 62-63) with mentum withdrawn into prosternum; ligula hemispherical with apex slightly pointed or rounded, and long setae on apical region; labial palpus 3-segmented; palpomere I triangular shorter than II and III; II as long as III, broader apically with long setae on sub-apical region; III sparsely setose with sensilla on apex.

Pronotum (Figs 11, 14, 17, 20, 23, 26, 29, 32, 35, 38) hemispherical or trapezoidal in dorsal view with anterior edge linear or slightly emarginate, broadest between middle and base; base broadly rounded with postero-medial edge extended, covering anterior half of scutellum; disc with explanate margin distinct or posterior half indistinct, smooth [except for Stoiba fascicollis (Fig. 20) and Stoiba marginata (Fig. 32)], slightly convex with longitudinal cleavage medially; margin area broader basally, slightly inclined upward, weakly punctate (except for some Stoiba flavicollis specimens withsmooth surface); profile irregularly trapezoidal, highest at base; lateral edge rounded to slightly angled with postero-lateral edge slightly extended.

Prosternum (Fig. 64) flat or slightly convex; anterior prosternal edge linear to slightly curved, forming cervical cavity; prosternal process smooth or occasionally with shallow depression, reaching mesocoxae with arrow-shaped apex.

Mesonotum (Fig. 65) transverse with basal edge line well-sclerotized, weakly fused to metanotum; scutellum well-sclerotized, triangular, convex with anterior half withdrawn into pronotal base.

Mesosternum (Fig. 67) deeply notched; mesepisternal ridge well defined; mesosternal process extended to posterior end of mesocoxal cavity, fused to metasternum.

Metanotum (Fig. 66) weakly sclerotized; scutellar groove and scutoscutellar suture distinct. Metasternum (Fig. 67) flat or slightly convex medially with distinct longitudinal line, transverse posteriorly, laterally declined; intercoxal notch distinct, as long as or slightly shorter than hind trochanter.

Elytra (Figs 11, 14, 17, 20, 23, 26, 29, 32, 35, 38) oval to round with base transverse, explanate laterally, moderately to distinctly convex; outline slightly to moderately discontinuous between anterior 1/3 and middle in dorsal view; surface fine scaled-like, shining to murky, finely to coarsely or roughly punctate; punctures evenly sized; brace (Fig. 95) distinct with posterior end weakly connected to longitudinal carina forming angle; color various; margin area broadest between anterior 1/3 and middle, gradually narrower posteriorly. Hind wing (Figs 92-93) fully developed or brachypterous.

Legs (Figs 13, 16, 19, 22, 25, 28, 31, 34, 37, 40) slender, long, shiny, brown to black, extending beyond elytral margin; trochanters short, triangular; femora moderately broad, broadest at middle, much narrower toward base rather than distal end; tibiae as long as femur or slightly shorter, slightly broader apically with apical end notched, broadest at notched region; distal 1/3 (lateral areas of notched region) coarsely setose; with tarsomeres I, II, III, IV dorsally convex with long setae; ventral surface densely setose, pale; tarsomere I small, rounded triangular; II with apex slightly bilobed, 2 times as long as I; III deeply bilobed, ca. 3 times as long as I; IV 3 times as long as tarsomere I, slightly broader apically, covering base of claws; claws evenly curved, tapered with quadrate basal tooth.

Abdomen (Figs 13, 16, 19, 22, 25, 28, 31, 34, 37, 40) fully covered by elytra, broad, rounded laterally, slightly convex medially; each ventrite well-sclerotized, same size in length (without hind coxal process on ventrite I), sparsely setose with posterior and lateral areas more setose; ventrite V much narrower than I–IV with longer setae.

Aedeagus (Figs 68-71) curved in lateral view (only Stoiba flavicollis and Stoiba swartzii dissected), laid laterally (male genitalia deversement) with aedeagal base piece oval, membranous structure basally, slightly broader apically with apex pointed; tegmen sclerotized, Y-shaped; spicule V-shaped with anterior end slightly extended; ejaculatory duct longer than base piece; seminal vesicle slightly longer than base piece with sclerotized bead between ejaculatory duct and seminal vesicle.

Spermatheca (Figs 72-80) irregular falcate or irregular J-shaped to C-shaped, short to elongated; receptacle distinct from pump with two openings; spermathecal duct various in shape and length, loosely coiled to moderately coiled or entwined.

Remarks.

We found some morphological variation especially in body shape, pronotum, and elytra. From the dissected or sex-determined specimens we considered those variations in males and females, but could not find any sexual dimorphism.

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