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).