Symmela nunesorum Pacheco, Wipfler, Monné and Ahrens, 2022

Pacheco, Thaynara L., Wipfler, Benedict, Monné, Marcela L. & Ahrens, Dirk, 2022, The genus Symmela Erichson, 1835 (Coleoptera, Scarabaeidae, Sericini): taxonomy and phylogenetic analysis, Journal of Natural History 56 (9 - 12), pp. 607-705 : 671-674

Symmela nunesorum Pacheco, Wipfler, Monné and Ahrens sp. nov.

( Figures 21 , 29 (d), 31(e), 32(g))

Type material examined

Holotype. ♂ ‘ BRASIL: Goiás. Mineiros. 1999 G. Machado / 29 Neotropical Sericini spec.’ ( CEMT) . Paratype: 1 ♂ ‘ BRASIL: Goiás . Mineiros. 1999 G. Machado / 29 Neotropical Sericini spec .’ ( ZFMK).

Description

Length: 6.8 mm. Elytral length: 4.4 mm. Width: 3.2 mm. Head black, shiny, with erect, sparse setae. Labroclypeus as wide as frons, subtrapezoidal; surface convex; plain, without an anterior concavity on each side; anterior margin straight, weakly reflexed, with a rim of dense, short setae behind anterior margin; lateral margin not incised anteriorly; punctation of surface posteriorly dense; suture between labrum and clypeus invisible. Smooth area in front of eye distinctly separated from frons by a suture. Frons anteriorly flat, punctation even, dense. Ocular canthus with terminal setae, ratio of length of ocular canthus/eye diameter: 1/3. Eyes evenly spherical, ratio of diameter/interocular width: 0.44. Antenna with eight antennomeres. Antennal club with three antennomeres, blackish, straight; width of antennal lamella equal to width of antennomeres of funiculus; apical lamella distinctly shorter than basal one; length ratio of antennal club vs remaining antennomeres combined: 1/1.5; length ratio of third vs fourth antennomere: 1/2; fourth antennomere without lateral projection; length ratio of fifth vs fourth antennomere: 1/3. Labrum anteriorly bluntly angled on each side, concave at middle. Setae on mentum moderately dense.

Head and pronotum without copper iridescent shine. Pronotum unicoloured, shiny, black; widest at base, width distinctly narrower compared to width of elytral base at humerus; anterior marginal line not interrupted medially, posterior marginal line absent; lateral margin not serrated, generally bent at middle, otherwise straight, behind anterior angles weakly concave, posteriorly straight; setae of lateral margin sparse; basal margin evenly curved; transverse impression beside basal margin present only laterally; anterior angles produced, sharply pointed; antero-lateral and postero-lateral angles not flattened dorso-ventrally; posterior angles blunt; surface without median longitudinal impression, transversal furrows or setae; punctation on disc moderately dense, simple and fine, without well-defined impunctate areas. Scutellum without punctures.

Elytra unicoloured, black; surface iridescent, without setae and microsculpture; striae and intervals distinct; punctation between striae sparse, diameter of punctures compared to those of striae smaller; intervals flat; posterior edge convex; apical margin chitinous, without microtrichomes.

Abdomen: sternites flat in sagittal plane; lateral carina absent; first visible ventrite with row of setae on posterior edge; second visible ventrite with row of setae in medial region; basal ventrites medially with half length as laterally; ultimate and penultimate apical ventrites simple and flat; apical ventrite short (as long as preceding ventrite); penultimate apical ventrite with row of setae like preceding one; beside the robust row of setae, almost glabrous. Pygidium strongly convex.

Legs blackish. Ratio of length of metepisternum/metacoxa:1/1.4. Metacoxa entirely plain, without elevated lateral longitudinal carina; without longer lateral bristles, with setae on basal surface, posterior margin glabrous. Metafemur with posterior margin straight. Metatibia widest at apex; ratio of width/length: 1/2.9; dorsal margin carinated, smooth; interior surface more or less glabrous; median longitudinal punctation present on interior surface; interior margin of apex sharply and deeply truncate towards ventral margin; punctation on entire lateral face present; beside dorsal margin without a row of robust setae along entire length; basal group of spines comprising at least two robust spines at same level of metatibial length; distal groups of spines disposed at two-thirds of metatibia length; ventral margin not serrated. Dorsal surface of tarsi glabrous, with dense punctures. Length ratio of dorsal tibial spur/first metatarsomere:1/2. Metatarsi at apex weakly widened; first tarsomere straight, its length subequal to second and third tarsomeres combined; laterally not carinate; ventral margin serrated;ventral margin glabrous;medial face glabrous. Protibia with two distinct teeth; spur straight. First protarsomere straight, as long as second; width ratio of first protarsomere vs second protarsomere: 1.5/1; second protarsomere narrow, but bent; third and fourth protarsomere elongate and narrow (distinctly longer than wide); fifth protarsomere circular in cross section, a little shorter than third and fourth protarsomere combined. Protarsal claws asymmetrical, shape of inner protarsal claw bifid, apex of basal tooth of inner protarsal claw convex.

Aedeagus: Figure 21 (c–d).

Female unknown.

Variation

Length: 6.2–6.8 mm. Elytral length: 4–4.4 mm. Width: 3.1–3.2 mm. Pronotum and elytra in paratype bicoloured: pronotum in basal half yellowish; elytra yellow with dark margins.

Diagnosis

Symmela nunesorum sp. nov. is in the shape of aedeagus very similar to S. capixaba . Symmela nunesorum differs by the pronotum which is distinctly narrower than the elytra at the humerus and its lateral margins bent at middle. Furthermore, S. nunesorum has a blackish body and the parameres are narrower at the apex (compared to body size, or length of phallobase). In S. capixaba , the body is yellowish brown and parameres are wider at the apex.

Etymology

This species is named after Rafael V. Nunes and Luis Gabriel de O.A. Nunes (not related); both are great Brazillian biologists and dear friends of the first author (noun in genitive case).

Figures

Figure 21. Symmela nunesorum sp. nov., holotype ♂. (a) Habitus, dorsal view; (b) habitus, lateral view; (c) parameres, dorsal view; (d) aedeagus, dorsal view; (e) aedeagus, lateral view. Scale bars: a, b = 1 mm; c–e = 0.5 mm.

Figure 29. Distribution map of the Symmela species.