Symmela beskei 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 : 616-619

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

( Figures 1 , 29 (a), 30(a))

Type material examined

Holotype. ♂ ‘ Brasilia New Friburgo b. Beske / Symela longula Er. / 78 Neotropical Sericini spec.’ ( ZMHB).

Description

Length: 5.5 mm. Elytral length: 3.7 mm. Width: 2.5 mm. Head blackish brown, 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: 0.54. Antenna with eight antennomeres. Antennal club with three antennomeres, yellowish, straight; width of antennal lamella equal to width of antennomeres of funiculus; apical lamella subequal to basal and median ones; length ratio of antennal club vs remaining antennomeres combined: 1/1.1; length ratio of third vs fourth antennomere: 1/3; 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 bicoloured, iridescent, blackish brown and yellowish; widest at middle, width subequal to width of elytral base at humerus; anterior marginal line not interrupted medially, posterior marginal line absent; lateral margin not serrated, generally weakly convex, behind anterior angles convex, posteriorly straight; setae of lateral margin sparse; basal margin evenly curved; transverse impression beside basal margin absent; 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 dense, simple and fine, without well-defined impunctate areas. Scutellum without punctures.

Elytra bicoloured, yellowish brown in major part, margins blackish; surface opaque and 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 of same length as laterally; ultimate and penultimate apical ventrites simple and flat; apical ventrite very short (half 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 yellow. Ratio of length of metepisternum/metacoxa: 1/1.36. Metacoxa entirely plain, without elevated lateral longitudinal carina; without longer lateral bristles and setae on basal surface, posterior margin glabrous. Metafemur with posterior margin straight. Metatibia widest at apex; ratio of width/length: 1/3.24; dorsal margin not carinated, smooth; interior surface more or less glabrous; median longitudinal punctation on interior surface; interior margin of apex sharply and deeply truncate towards ventral margin; punctation on entire lateral face; 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, a little longer than second; width ratio of first protarsomere vs second protarsomere: 1.5/ 1; second protarsomere narrow and straight; third and fourth protarsomere elongate and narrow (distinctly longer than wide); fifth protarsomere circular in cross section, as long as 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 1 (c,d).

Female unknown.

Diagnosis

Symmela beskei sp. nov. is, in its external appearance and the shape of the aedeagus, similar to S. brasiliensis Moser, 1919 . It differs by the strongly reflexed anterior margin of the labroclypeus as well as by the subparameres being largely fused with the parameres; the parameres in the new species are also more elongate and dorso-ventrally slightly flattened; in S. brasiliensis the protibia is very short, its apical tooth elongated and half the protibial length, while in S. beskei the apical tooth is short, subequal to one-quarter of protibial length.

Etymology

The species is named after C.H. Beské, the collector of the type specimen (noun in genitive case).

Figures

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

Figure 29. Distribution map of the Symmela species.