Cryptocanthon Balthasar

Cook, Joyce, 2002, A Revision Of The Neotropical Genus Cryptocanthon Balthasar (Coleoptera: Scarabaeidae: Scarabaeinae), The Coleopterists Bulletin (mo 1) 56, pp. 3-96 : 4

Cryptocanthon Balthasar

Cryptocanthon Balthasar 1942:36 ; Howden 1973:39; Howden and Young 1981:39.

Type Species. Cryptocanthon paradoxus Balthasar 1942 , by monotypy.

Diagnosis. The position of the eyes posterior to the vertex, not or slightly visible when head is fully retracted, distinguishes Cryptocanthon from all related New World genera.

Description. Body. Oval ( Fig. 1 ); convex dorsally ( Fig. 3); integument dark brown, shiny, setose. Total length 3.0– 5.2 mm, greatest width 1.7–3.2 mm. Head. Broader than long, flattened, densely punctate. Clypeus shallowly concave; anterior margin with two acute, reflexed teeth separated by U-shaped emargination; teeth more prominent in female; anterior face with or without median fovea ( Fig. 4). Clypeofrontal suture obsolete. Front moderately convex. Clypeogenal suture prominently to weakly indicated. Genae produced anteriorly ( Fig. 64) or not ( Fig. 12) at margin with clypeus. Eyes posterior to vertex, not or slightly visible dorsally when head retracted. Antennae ( Fig. 5) 9-segmented with 3-segmented, tomentose club. Mouthparts. Labrum ( Fig. 8) with numerous fine setae apically; ventrally in apical half with two longitudinal rows of stronger setae, smaller setae medially. Left mandible ( Fig. 10) with apical and medial fringe of pectinate setae; molar surface concave, dorsal margin comb-like. Right mandible ( Fig. 9) with pectinate setae apically; molar surface convex with row of narrow ridges posteromedially. Maxilla ( Fig. 6) with lacinia and galea densely setose dorsally and apically; palpus 4-segmented, basal segment small, segment 2 twice length of segment 3, apical segment elongate, fusiform. Labium ( Fig. 7) shallowly emarginate apically; labial palpus 3-segmented; basal segment smaller than second segment, both with elongate setae; apical segment minute. Pronotum ( Figs. 1–3 ). Pronotum short and broad, length about one-half width; convex medially, flattened anterolaterally; anterior margin broadly emarginate; sides nearly straight to weakly arcuate in basal threefourths, then obtusely angled, joining anterior margin in near right angle; posterior angles usually obtusely rounded, occasionally incised before base; marginal bead absent. Pronotal hypomeron excavated anteriorly, often with incomplete longitudinal carina in basal half ( Fig. 2). Scutellum not visible. Elytra. Convex; each elytron dorsally with seven striae, each stria indicated by two parallel wavy lines ( Fig. 1 ); elytral intervals flat to slightly convex, usually with row of setose punctures on each side of each interval; each elytron sharply inflexed lateral to seventh stria, forming broad pseudepipleuron. Pseudepipleuron bearing striae 8–10; striae 8 and/or 9 often incomplete or absent; stria 10 indicated by row of punctures near epipleural margin; often with small basal fovea near epipleural margin ( Fig. 2). Epipleuron raised slightly above level of pseudepipleuron, narrower than pseudepipleuron. Wings. Hindwings fully developed in some species, reduced to minute knobs in others. Venter. Prosternum short, sharply angled between coxae. Mesosternum short and broad, anterior margin evenly curved, posterior margin rounded to slightly angulate medially. Metasternum broad between mesocoxae; evenly convex to flattened or depressed medially; carina extending posteriorly on each side from meso-metasternal suture posteriorly around base of mesocoxae ( Fig. 2). Legs. Protibiae narrow at base, broad and truncate apically; laterally with three marginal teeth, teeth larger in females ( Fig. 75 ), usually with several additional smaller teeth; inner margin variously modified medially and apically in males; one unmodified spine apically. Protarsi short ( Fig. 1 ), length about equal to width of protibial apex. Mesotibiae and metatibiae narrow at base, widened apically; metatibiae often elongated or angulate in males. Mesotarsi and metatarsi with segments 1 and 2 subequal in length, segments 3 and 4 progressively shorter and narrower, segment 5 slightly shorter than 3 1 4. Abdomen ( Figs. 2, 3). Pygidium convex, often with median swelling or longitudinal ridge; base cariniform, often with median sulcus. Ventrally with six visible sternites; apical sternite about three times longer medially than fifth sternite. Male genitalia. Basal piece curved, cylindrical; parameres well sclerotized basally, laterally and apically. Each paramere expanded medially as broad, thin lamella; usually lamella of left paramere overlaps that of right; occasionally reversed ( Fig. 59 ) and not always consistent within a species; in some species medial lamellae meet at midline ( Fig. 14). Paramere apices variously modified. Female genitalia. Spermatheca cylindrical, curved, tapered apically.

Figures

Fig. 1. Cryptocanthon otonga. Habitus, male.

Figs. 75–77. Cryptocanthon lindemanae. 75) left protibia, female; 76) clypeal outline, female;

Figs. 57–61. Cryptocanthon cristobalensis. 57) left protibia, male; 58) clypeal outline; 59) parameres, dorsal; 60) aedeagus, lateral; 61) elytra, posterior. Scale line 5 0.5 mm (Figs. 57–60), 1.0 mm (Fig. 61).