Ovomanonychus, Costa & Cherman & Iannuzzi, 2020

Costa, Fábio Correia, Cherman, Mariana Alejandra & Iannuzzi, Luciana, 2020, Ovomanonychus, a new genus of South American Sericoidini (Coleoptera Scarabaeidae: Melolonthinae), Zootaxa 4759 (1), pp. 65-76 : 66-70

Ovomanonychus Costa, Cherman, & Iannuzzi, new genus

Type species. Manonychus rosettae Frey, 1976 , here designated.

Diagnosis. Ovomanonychus is distinguished from all other Sericoidini by the following combination of characters: ovate body; labrum vertical, with superior margin inflated, hidden below the clypeus, not on same plane; galea with outer margin curved; labium longer than it is wide; antennae with nine antennomeres and club (with three antennomeres) longer than flagellum; absence of membrane along median of anterior pronotal margin; six fused ventrites, except the VI articulate; ventrite I with basal half hidden by metacoxae and ventrite VI one quarter the length of other ventrites; ventrite V and propygidium separated by suture; tarsomeres with sparse setae ventrally; elytra with strong costae; procoxae conical; apical protibial spur in both sexes; mesocoxae three times longer than wide; metacoxae longer than ventrite II; mesotarsomere I longer than mesotarsomere II; claws simple on all tarsi; metatibia with two apical spurs, spurs set below and above the tarsal articulation.

Description. Length: 10.0–12.0 mm; width: 4.0– 5.5mm. Body reddish brown, ovate sides slightly arcuate at middle of elytra ( Fig. 1A ). Head: Anterior margin rounded; distance between eyes twice or three times the width of one eye; frons densely punctate; frontoclypeal suture strongly impressed; canthus covered by clypeus; clypeus trapezoidal, punctate ( Fig. 1E ), strongly reflexed, and separated from labrum by a suture; labrum with superior margin bulged, vertical, hidden below the clypeus, not on same plane; galea of maxilla with outer margin curved ( Fig. 1B ); galea with tooth I projected; lacinia with distal portion forming a tooth–like projection; labium densely setose along the lateral margin, longer than wide ( Fig. 1D ); palp insertion covered by the labium and placed submedially; ligula and labium fused; antennae with nine antennomeres, club with three antennomeres and longer than flagellum ( Fig. 1E ). Prothorax: Pronotum wider than long, glabrous, densely punctate, disc narrowly smooth along midline; absence of membrane along median of anterior pronotal margin ( Fig. 1E ); anterolateral region slightly depressed; lateral margin sparsely setose; anterior angle rounded; anterolateral margin arcuate, posterolateral margins straight; proepimeron smooth laterally. Pterothorax: Scutellum subtriangular; mesosternum with foveolate, bristled punctures; internal posterior angle of mesepimeron acute and projected; metasternum bristles long; distance between the mesocoxae and metacoxae equal to length of metacoxae; metepisternum with coarse punctures. Elytra: Shiny, with costae parallel to the elytral suture, which is elevated ( Fig. 1A ). Legs: Procoxae conical, with sparse punctures on proximal region; profemurs with aggregated punctures extending from the base to the disc; protibia with sculpture and three teeth well developed, tooth II forming an acute angle with tooth III; apical protibial spur in both sexes; protarsomeres cylindrical; mesocoxae contiguous, punctate distally and three times longer than wide; mesofemur with parallel double row of punctures; mesotibia gradually enlarged towards apex, and with two transverse carinae; transverse carina II incomplete (non-reaching inner margin of mesotibia); two apical spurs, spurs set below and above the tarsal articulation; mesotarsomere I longer than mesotarsomere II ( Fig. 2A ); metacoxae longer than ventrite II, with dense or sparse bristles; metacoxal lateral margin in obtuse angle; metafemur with row of punctures posteriorly and smooth basally; transverse carina II incomplete; metatibial apical spurs with equal or different size ( Fig. 2B ), spurs set below and above the tarsal articulation; apex of metatibia prominent at the tarsal articulation; ventral surface of all tarsomeres with sparse bristles ( Fig. 1F ); all claws simple. Abdomen: Six fused ventrites, except ventrite VI which is articulate; ventrite I with basal half hidden by metacoxae and ventrite VI one quarter the length the others ( Fig. 2C ); lateral keel along the ventrites; ventrites II–VI with transverse row of setose punctures; pygidium and propygidium separated by suture; propygidium punctate. Male genitalia: Parameres symmetrical, converging at apex; outer margin slightly curved on distal third; inner margin on distal portion curved; medial portion of proximal margin lobed.

Sexual dimorphism. Males and females are quite similar, except in the protibial tooth I stronger in females and pygidium slightly convex in females and flat in males.

Etymology. Adjective in the nominative singular. From the Latin ovum (“egg”) + Manonychus in reference to the body shape and original placement of the type species. The name is masculine in gender.

Composition. Ovomanonychus rosettae ( Frey, 1976) new combination, Ovomanonychus inajae new species, and Ovomanonychus striatus new species.

Geographical distribution. Endemic to the Midwest (Mato Grosso), Southeastern (Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo), Northeastern (Bahia), and Southern (Paraná) regions of Brazil ( Fig.3 ).

Remarks. Ovomanonychus new genus resembles Manonychus in the labrum hidden by the clypeus (in dorsal view), with superior margin inflated; and labium quadrate. Ovomanonychus differs from Manonychus (characters in parenthesis), in the galea with outer margin curved ( Fig. 1B ) (galea with outer margin lobed; Fig. 1C ); elytra with costae ( Fig. 1A ) (elytra almost smooth); tarsomeres in all legs with sparse bristles ventrally ( Fig. 1F ) (protarsomeres and mesotarsomeres with pads; Fig. 1G ); metacoxae longer than ventrite II ( Fig. 2C ) (metacoxae length equal to ventrite II; Fig. 2D ).

We place Ovomanonychus new genus in Sericoidini based on the following combination of characters: labrum hidden by the clypeus (in dorsal view); clypeus and labrum separate by suture; ligula and labium fused; metatibial apically with two spurs, spurs set below and above the tarsal articulation; lateral keel along the abdominal ventrites; abdomen with six ventral sternites (basal sternite partially hidden by metacoxae), sternites approximately equal in length, evenly convex, separated by distinct sutures ( Smith 2008).

Figures

FIGURE 1. Ovomanonychus diagnostic characters. A,Ovomanonychus striatus new species male paratype dorsal habitus; B, O. striatus right maxilla, galea with outer margin curved; C, Manonychus birabeni Martínez, 1959 right maxilla, galea with outer margin lobed; D, O. striatus labium; E, O. rosettae (Frey, 1976) frons and antennae; F, O. rosettae left anterior tarsomeres with sparse bristles; G, M. birabeni right anterior tarsomeres with pads.

FIGURE 2. Ovomanonychus diagnostic characters. A, Ovomanonychus rosettae (Frey, 1976) mesotarsomere; B, O. inajae new species spurs set below and above the tarsal articulation; C, O. rosettae metacoxae longer than ventrite II; D, Manonychus ovalis (Blanchard, 1851) metacoxae length equal to ventrite II; E, O. striatus new species metacoxae densely bristled; F, O. rosettae apical region of phallobase excavated.

FIGURE 3. Distribution map of Ovomanonychus new genus: Ovomanonychus inajae new species (red square), Ovomanonychus striatus new species (yellow circles), and Ovomanonychus rosettae (blue diamonds).