Agamopus joker, Costa-Silva & Carvalho & Vaz-De, 2022

Costa-Silva, Vinícius, Carvalho, Edrielly & Vaz-De, Fernando Z., 2022, A taxonomic revision of the New World genus Agamopus Bates, 1887 (Coleoptera: Scarabaeinae: Ateuchini), European Journal of Taxonomy 806 (1), pp. 64-89 : 69-73

Agamopus joker sp. nov.

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Figs 3–4 , 5B

Differential diagnosis

Agamopus joker sp. nov. shares with A. viridis the presence of two small tubercles on the head ( Fig. 5B – white arrows). However, the two species can easily be distinguished by the shape of the pygidial sulcus, which is arched in A. viridis (and other Agamopus species – as in Fig. 9E ), but sinuous in A. joker ( Fig. 4D ). Furthermore, the inner edge of the metatibia is noticeably curved and strongly crenulate in A. joker , being unique among representatives of the genus ( Fig. 4C ). Also, A. joker has the apex of the parameres abruptly curved downwards and flattened dorso-ventrally ( Fig. 4E ), differing from other species of Agamopus .

Etymology

The specific name ‘ joker ’, an English proper noun in the nominative case used in apposition, is an eponym after the homonymous supervillain from the DC Comics Universe. It is a reference to the sinuous pygidial sulcus of this species, which resembles the shape of a smiley clown’s mouth.

Type material

Holotype BRAZIL • ♂; first label [aged white, unknown handwriting]: “2 – 49 [vertical] / P. Grossa / Lageado.”; second label [aged white, unknown handwriting]: “5211 [vertical] / Agamopus / viridis / Bouc.”; third label [aged white, Pereira's handwriting]: " Agamopus / viridis 5211 / Bouc. / P. Pereira det. [typeset] 99 [Pereira's handwriting]"; fourth label [red with black border, printed]: Agamopus joker ♂ / Costa-Silva et al., 2022 / HOLOTYPE"; CEMT ( Fig. 4G ).

Holotype description

Habitus as in Figs 4A‒B . Colour: dark brown, metallic. Oblong body. Length: 5.6 mm (excluding head). Width: 3.8 mm.

HEAD. Hemispheric. Surface with dense punctation; anterior half foveolate-puncticulate and with erect yellow setae. Clypeal margin and lateral margin of head with yellow setae projecting from underneath. Two triangular clypeal teeth, separation between teeth V-shaped. Lateral clypeal carina well-defined and

oblique (as in Fig. 5B – red arrows), ending in small tubercle on each side. Antennae yellow; antennal club covered by small golden bristles.

PRONOTUM. Dark brown, metallic, shiny. Wider (3.18 mm) than long (1.7 mm); delimited by carina around. Surface covered by dense and homogeneous punctation ( Figs 4A and 5B ). Anterior angles rounded, pointed forward. Lateral margin smooth; rounded. Hypomeron with surface subtly rugose and densely punctate; anterior half deeply excavated, separated from posterior half by well-defined carina; posterior half with a longitudinal keel slightly marked, parallel with lateral margin ( Fig. 4B – black arrow).

MESOVENTRITE. Trapezoidal; anterior margin wider than posterior. Surface fully punctated. Mesometasternal suture straight.

METAVENTRITE. Fully punctated. Punctures larger and well-marked between mesocoxae; punctures slightly smaller in the posteromedial region ( Fig. 4B ).

ELYTRA. Suboval. Lateral margins slightly angled. Seven striae well-defined; punctation equidistant on each stria. Surface of interstriae covered by micropunctation.

LEGS. All fully covered by punctation. Protibiae slightly curved; three main teeth on outer edge and subtly crenulated to the base; inner apical angle of protibiae ~ 90°; ventral surface with longitudinal carina from base to apex. Meso- and metafemora with posterior edge smooth. Mesotibiae gradually widened apically; apical width approximately 1/4 of total length. Metatibiae visibly arched; inner edge crenulate with yellow setae ( Fig. 4C ); parallel margins in the anterior half, expanding slightly in the posterior half. Inner margin with a projection beyond apex, near to the spur. First to fourth protarsomeres almost rounded; 5 th tarsomere elongate, longer than first three tarsomeres culminated; apex truncate. Meso- and metatarsomeres equal in shape and length; first to third tarsomeres with dense ventral yellow setae. Tarsal claws falciform; longer than first tarsomere ( Fig. 4A–C ).

ABDOMEN. Six ventrites; each ventrite with row of punctation in the anterior margin; sides with sparse punctation. Lateral part of each ventrite longer than in the middle. Sixth ventrite completely covered by well-marked punctation.

PYGIDIUM. Wider than long; glabrous, covered by micropunctation. Deep transverse and sinuous sulcus in centre of disc ( Fig. 4D ).

MALE GENITALIA. Lateral view: parameres symmetrical; phallobase with dorsal gibbosity near base ( Fig. 4E – black arrow); distal portion of parameres abruptly curved downwards ( Fig. 4E ). Dorsal view: tips of parameres trapezoidal, expanded laterally, pointed ( Fig. 4F ).

Female

Unknown.

Geographic distribution

The species is only known from type locality, Ponta Grossa, Paraná, Brazil ( Fig. 3 ).

Figures

Fig. 3. Geographical distribution map of Agamopus joker sp. nov. (blue circle); A. unguicularis (Harold, 1883) (green circles); and A. castaneus Balthasar, 1938 (red circles).

Fig. 4. Agamopus joker sp. nov. Holotype, ♂ (CEMT). A. Habitus, dorsal view. B. Habitus, ventral view (black arrow indicating the longitudinal keel slightly marked). C. Hind tibia (black arrow indicating the elongate apical process in the metatibia). D. Sulcus in the pygidium. E. Aedeagus, lateral view (black arrow indicating the gibbosity near base). F. Aedeagus, dorsal view. G. Labels. Scale bars = 1 mm.

Fig. 5. Cephalic integument of species of Agamopus Bates, 1887. A. A. lampros Bates, 1887 (CEMT): smooth and lacking tubercles.B. A. joker sp. nov., holotype, ♂ (CEMT), with dense punctuation and two small tubercles. White arrows indicating the small cephalic tubercles. Red arrows indicating the lateral clypeal carina. Scale bars = 1 mm.

Fig. 9. A‒D. Agamopus viridis Boucomont, 1928. Holotype, ♀ (MNHN). A. Habitus, dorsal view. B. Habitus, ventral view. C. Habitus, lateral view. D. Labels. E. Sulcus of the pygidium in an ordinary specimen (CEMT). Photographs A‒D: Christophe Rivier, MNHN.