Symmela marcelae Pacheco & Ahrens, 2023

Pacheco, Thaynara L. & Ahrens, Dirk, 2023, Addendum to the revision of the South American genus Symmela Erichson, 1835 (Coleoptera: Scarabaeidae: Melolonthinae: Sericini): a further new species from Brazil, Zootaxa 5263 (2), pp. 297-300 : 297-299

Symmela marcelae Pacheco & Ahrens , new species

Figure 1

Type material examined. Holotype: ♁ “ Cachimbo Prov. de Bahia Ch. Pujol 1890/ Muséum Paris R. Oberthür 1952” ( MNHN).

Description of holotype. Length: 7.5 mm. Elytral length: 4.5 mm. Width: 3.2 mm. Body entirely yellow, surface shiny, dorsal surface glabrous, head and pronotum without cupreous iridescent shine. Labroclypeus as wide as frons, subtrapezoidal; surface weakly convex; without an anterior concavity on each side; anterior margin straight, strongly reflexed, with a rim of sparse setae behind anterior margin; lateral margin not incised anteriorly; punctation of surface anteriorly almost missing, posteriorly moderately dense; suture between labrum and clypeus indistinct. Smooth area in front of eye indistinctly separated from frons. Frons anteriorly with a concave impression on each side, punctation even and dense. Ocular canthus with terminal setae, ratio length of ocular canthus/eye diameter: 1/3. Eyes evenly spherical, ratio diameter/interocular width: 0.91. Antenna missing in holotype. Labrum anteriorly bluntly angled each side, concave at middle. Mentum anteriorly weakly emarginate, setae moderately dense.

Pronotum iridescent shiny; widest from middle to base, subequal in width compared to width of elytral base at humerus; anterior marginal line robust, not interrupted medially; basal margin evenly curved, basal marginal line fine but complete; lateral margins not serrated, weakly evenly convex, in basal half almost straight and subparallel; setae of lateral margin completely lacking; transverse impression beside basal margin absent; anterior angles produced, sharply pointed; anterolateral and posterolateral angles not flattened dorsoventrally; posterior angles blunt; surface without median longitudinal impression, transversal furrows or setae; punctation on disc dense, simple and fine, without well-defined impunctate areas. Scutellum dull, with fine, sparse punctures.

Elytra unicolored yellow; surface shiny, partly iridescent, without setae and microsculpture; striae and intervals distinct; punctation between striae sparse, diameter of punctures smaller compared to those of striae; intervals flat; apical margin convex and chitinous, without microtrichomes.

Abdomen: sternites flat in sagittal plane; lateral carina absent; first ventrite with row of setae in posterior edge on an elevated carina; second ventrite with row of setae in medial region; basal ventrites along midline half as long as laterally; ultimate and penultimate ventrites simple and flat; ultimate ventrite short (as long as precedent ventrite); penultimate ventrite with row of setae as precedent ventrite; beside the robust row of setae, almost glabrous. Pygidium strongly convex.

Legs yellow. Ratio of length of metepisternum/metacoxa: 1/1.32. Metacoxa entirely smooth, without elevated lateral longitudinal carina; laterally and on base with longer setae, posterior margin glabrous. Metafemur at posterior margin evenly weakly convex. Metatibia widest at apex; ratio of width/length: 1/2.7; dorsal margin not carinate, smooth; interior face more-or-less glabrous; median longitudinal punctation on interior face present; interior margin of apex sharply and deeply truncate towards ventral margin; punctation on entire lateral face fine and dense; beside dorsal margin without a row of robust setae along entire length; basal group of spines reduced to a single robust spine; distal groups of spines disposed at two thirds of metatibia length; ventral margin not serrate. Dorsal surface of tarsi glabrous, with dense punctures. Length ratio dorsal tibial spur/first metatarsomere: 1/2. Metatarsi at apex weakly widened; first tarsomere straight, its length subequal to second and third tarsomeres combined, not carinate laterally; ventral margin serrate and glabrous; medial face glabrous. Protibia with two distinct lateral teeth; tibial spur straight. Protarsomeres entirely lacking in holotype.

Habitus: Figure 1A–C . Aedeagus: Figure 1D–F .

Female unknown.

Diagnosis. Symmela marcelae Pacheco & Ahrens , new species, differs from all other species of Symmela by its large body size (7.5 mm, most other species usually smaller than 7.2 mm), the uniformly yellow body color with its shinyiridescent integument, and by the shape of the parameres, which are elongate and narrow and basally fused with the subparameres producing a large, interiorly directed basal lobe.

Etymology. The species is named after Marcela L. Monné Freire (Museu Nacional, Rio de Janeiro, Brazil) (noun in genitive case), as a big thank you for all the help and support to T.L.P. during her thesis research.

Key: This species can be separated from others by modifying couplet 8 of Pacheco et al. (2022d) key as follows:

8. Parameres half as long as phallobase excluding basal apodeme........................... S. mutabilis Erichson, 1835

- Parameres almost subequal in length to phallobase excluding basal apodeme..................................... 8a

8a Subparameres fused medially. Phallobase not widened at middle (lateral view)............................................................................................ S. guerlini Pacheco, Wipfler, Monné, and Ahrens, 2022

- Subparameres separated medially. Phallobase strongly widened at middle (lateral view)............................................................................................. S. marcelae Pacheco & Ahrens , new species

Figures

FIGURE 1. Symmela marcelae Pacheco & Ahrens, new species, holotype ♁; A) Habitus, lateral view; B) habitus, dorsal view; C) head, dorsal view; D–E) aedeagus, dorsal view, F) aedeagus, lateral view. Scales bars: A–B, 1 mm; C–F, 0.5 mm.