Symmela elegans 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 : 633-636

Symmela elegans Erichson, 1835

( Figures 7 , 29 (b), 30(g), 32(c))

Symmela elegans Erichson, 1835: 263 (original description); Blanchard 1850: 85 (catalogue); Burmeister 1855: 133 (revision); Harold 1869: 1126 (checklist); Frey 1973: 322 (key); Evans 2003: 48; Evans and Smith 2005: 30, 2007: 30, 2009: 31 (checklist)

Type material examined

Holotype. ♀ ‘24972/ elegans Er. Brasil v. Langs. / Typus’ ( ZMHB).

Additional material examined

1 ♂ ‘ Brésil / Symmela instabilis Er. ’ ( MNHN) , 1 ♂ ‘ flavimana Gory instabilis Dej. Brésil 2/2’ ( MNHN), 1 ♂ ‘ Lambary M . Geraes . XI.1924 7383 J. Halik / Symmela / Brasil Halik 1966 Collection’ ( USNM), 1 ♀ ‘ Lambary, Minas II . 924/ Coll . J . Guerlin S . Paulo , Brasil 11794/ Symmela elegans det . G . Frey 1972’ ( CF / NHMB), 2 ♂♂ ‘ Venda Nova de Imigrante ES-BRASIL XI-1999 Col . Vaz Mello / 26 Neotropical Sericini spec.’ ( CEMT) , 1 ♂, 1 ♀ ‘R. d. Janeiro Petropolis 6.11 .04 F. Ohs / Symela elegans Er . [handwritten Frey ]’ ( ZMHB), 1 ♂ ‘R . d. Janeiro Petropolis 6.11 .04 F. Ohs / Mos . determ . Symmela elegans Er. / CASENT 8438098’ ( CAS), 1 ♂ ‘ Brazil, 300–500 m, Nova Teutonia 27°11 ʹ S, 52°23 ʹ W . Jan . 1969 Fritz Plaumann’ ( CMNC), 1 ♂, 1 ♀ ‘ Brasilien Nova Teutonia 27°11 ʹ B 52°23 ʹ L Fritz Plaumann X.1957 300–500 m’ ( CNCI).

Redescription

Length: 6.9 mm. Elytral length: 4.2 mm. Width: 3.7 mm. Head black, shiny and iridescent, with erect, sparse setae. Labroclypeus as wide as frons, subtrapezoidal; surface convex; plain, without an anterior concavity on each side; anterior margin straight, 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 irregular, dense. Ocular canthus with terminal setae, ratio of length of ocular canthus/eye diameter: 1/3. Eyes evenly spherical, ratio of diameter/ interocular width: 0.47. 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 with copper iridescent shine. Pronotum unicoloured, iridescent, blackish brown; widest at middle, width distinctly narrower compared to width of elytral base at humerus; anterior marginal line not interrupted medially, posterior marginal line absent; lateral margin serrated, generally bent at middle, otherwise straight, behind anterior angles straight, posteriorly weakly convex; setae of lateral margin dense; basal margin evenly curved; transverse impression beside basal margin absent; anterior angles produced, rectangular; antero-lateral angle flattened dorso-ventrally, postero-lateral angle not flattened dorso-ventrally; posterior angles blunt; surface with median longitudinal impression present over entire length of pronotum and two longitudinal furrows on each side, punctation on disc dense, simple and fine, without well-defined impunctate areas. Scutellum without punctures.

Elytra bicoloured, reddish brown in major part, dark margins; surface opaque, 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 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 blackish. Ratio of length of metepisternum/metacoxa: 1/1.4. Metacoxa entirely plain, without elevated lateral longitudinal carina; with longer lateral bristles, without setae on basal surface, posterior margin glabrous. Metafemur with posterior margin straight. Metatibia widest at apex; ratio of width/length: 1/3.55; 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: 1/3. 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 setose.

Aedeagus: Figure 7 (d,e).

Variation

Protibia with three indistinct, equidistant teeth; third basal tooth smaller than medium tooth; spur curved interiorly. First protarsomere curved, 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.

Remarks

The original description was based on a single specimen ( Erichson 1835, p. 263); the present type specimen must be considered the holotype. This specimen is a female; the protibia is lacking.

Figures

Figure 7. Symmela elegans Erichson, 1835. (a–c) holotype ♀, (d–e) non type specimen ♂. (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.