Symmela erichsoni 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 : 636-638

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

( Figures 8 , 29 (b), 30(h))

Type material examined

Holotype. ♂ ‘ Rio Jan / Type mgl./ Symela opaca Er. / 80 Neotropical Sericini spec.’ ( ZMHB) . Paratypes: 2 ♂♂ ‘Fry Rio Jan ./ Fry coll. 1905–100./ Symmela mutabilis Er. Det. at B.M. H.F. Howden ‘62 / Symmela mutabilis ’ (CNCI, ZFMK) .

Description

Length: 5.1 mm. Elytral length: 3.2 mm. Width: 2.6 mm. Head blackish brown, iridescent, 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 sparse 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 irregular, moderately dense. Ocular canthus with terminal setae, ratio of length of ocular canthus/eye diameter: 1/3. Eyes evenly spherical, ratio of diameter/interocular width: 0.49. Antenna with eight antennomeres. Antennal club with three antennomeres, blackish, 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: 1/5. Labrum anteriorly bluntly angled on each side, concave at middle. Setae on mentum moderately dense.

Head and pronotum without copper iridescent shine. Pronotum unicoloured, iridescent, blackish brown; widest at middle and base, width subequal 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 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 dorsoventrally; 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, blackish brown; 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 in posterior edge on an elevated carina; 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 and yellow. Ratio of length of metepisternum/metacoxa: 1/1.22. 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: 1/3.33; dorsal margin not 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 reduced to a single robust spine; 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 curved, its length longer than second, third and fourth combined; width ratio of first protarsomere vs second protarsomere: ca. 1/2; second protarsomere enlarged; third and fourth protarsomere short and transverse (distinctly wider than long); 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 8 (c,d).

Female unknown.

Variation

Length: 5.1–6.0 mm. Elytral length: 3.2–3.8 mm. Width: 2.6–3.1 mm. Pronotum bicoloured, basal lateral margins yellowish; elytra bicoloured, yellowish brown with dark margins.

Diagnosis

Symmela erichsoni sp. nov. differs from S. beskei by the enlarged first protarsomere, which is longer than second, third, and fourth protarsomere combined, and by the shorter and stouter parameres which are flattened laterally instead of dorso-ventrally.

Etymology

The species is named after W.F. Erichson, a German entomologist who described the genus Symmela and many other taxa (noun in genitive case).

Figures

Figure 8. Symmela erichsoni sp. nov., holotype ♂. (a) Habitus, dorsal view; (b) habitus, lateral view; (c) aedeagus, lateral view; (d) aedeagus, dorsal view. Scale bars: a, b = 1 mm; c, d = 0.5 mm.

Figure 29. Distribution map of the Symmela species.