Symmela nitida Erichson, 1835

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 : 665-668

Symmela nitida Erichson, 1835

( Figures 19 , 29 (c), 31(c))

Symmela nitida Erichson, 1835: 264 (original description); Blanchard 1850: 85 (catalogue); Burmeister 1855: 134 (revision); Harold 1869: 1127 (checklist); Frey 1973: 323 (key); Evans 2003: 49; Evans and Smith 2005: 31, 2007: 31, 2009: 31 (checklist)

Symmela tenella Erichson, 1835: 265 (original description); Burmeister 1855: 135 (revision); Harold 1869: 1127 (checklist); Frey 1973: 324 (key); Evans 2003: 49; Evans and Smith 2005: 31, 2007: 31, 2009: 32 (checklist), syn. nov.

Type material examined

Holotype ( S. nitida ): ♂ ‘24990/ nitida Er. / Brasil. Virm./ keine Type... [further text not legible]/ tenella Er. Coll. Moser [handwritten Frey]’ ( ZMHB). Lectotype ( S. tenella , here designated) ♂ ‘ tenella Er. Brasil Setl./ 24985/ Typus’ ( ZMHB). Paralectotypes ( S. tenella ): 1 ♀ ‘24988/ var? Brasil Virm./ Berlin/ tenella coll. Moser’ ( ZMHB), 2 ♂♂, 1 ♀ ‘ Brasil Virmond Nr. 24988/ Typus/ Berlin/ tenella coll. Moser’ ( ZMHB), 2 ♂♂ ‘ Brasil Virmond Nr. 24988/ Berlin/ tenella coll. Moser’ ( ZMHB), 1 ♂ ‘24989/ Var. Brasil Virm./ Type/ Berlin/ tenella coll. Moser’ ( ZMHB), 1 ♂ ‘ Brasil Sello Nr. 24987/ Typus/ tenella coll. Moser’ ( ZMHB).

Additional material examined

1 ♂ ‘ nitida Er. Bras. Dpt’ . ( MLUH) , 1 ♂ ‘S. Paulo Mato d . Gov . F. Ohaus S./ Ohaus determ . Symmela nitidicollis ♂ Burm. ’ ( ZMHB) , 1 ♂ ‘S. Bocaina 1600 m S .J. BARREIROS S.P. Brasil XI-1967 Alvarenga e Seabra / Coleção M . Alvarenga / DZUP 311714/ 31 Neotropical Sericini spec.’ ( DZUP) , 1 ♂ ‘ BRASIL, Paraná, Tibagi P .E. Canion Guartelá 06-XII- 2009, 900 m, P .C . Grossi leg ./ 33 Neotropical Sericini spec.’ ( CEMT) , 1 ♂ ‘Museum Paris Minas Ger. à Goyaz Castelnau 1947/ S . tenella / tenella Det. L.W. Saylor / CASENT 8438104’ ( CAS), 1 ♂ ‘ Museum Paris Minas Ger. à Goyaz Castelnau 14–47/ CASENT 8438105’ ( CAS), 1 ♂ ‘ Brasilien / L .W. Saylor Collection / CASENT 8438108’ ( CAS) .

Redescription

Length: 5.1 mm. Elytral length: 3.5 mm. Width: 2.8 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 convex, not elevated, 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, sparse. 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: 1/2; 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, shiny, blackish brown; widest at 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 weakly convex, behind anterior angles convex, posteriorly weakly convex; 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 moderately dense, simple and fine, without well-defined impunctate areas. Scutellum without punctures.

Elytra bicoloured, black in major part, posterior half dark; surface shiny, without setae and microsculpture; striae and intervals distinct; punctation between striae sparse, diameter of punctures compared to those of striae equal; 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 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 weakly convex.

Legs yellow. Ratio of length of metepisternum/metacoxa: 1/1.28. 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: 1/2.95; 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 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 indistinct teeth; spur straight. First protarsomere straight, its length subequal to second and third combined; width ratio of first protarsomere vs second protarsomere: 1.5/1; second protarsomere enlarged; 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 19 (d,e).

Remarks

The original description was based on a single specimen ( Erichson 1835, p. 265); the available type specimen must be considered the holotype. Except for the variable colour, the types of Symmela nitida and S. tenella are virtually identical, i.e. in the shape of the parameres, labroclypeus and protarsi.

Figures

Figure 19. Symmela nitida Erichson, 1835, holotype ♂. (a) Habitus, dorsal view; (b) habitus, lateral view; (c) labels; (d) parameres, dorsal view; (e) aedeagus, lateral view. Scale bars: a, b = 1 mm; d, e = 0.5 mm.

Figure 29. Distribution map of the Symmela species.