Symmela longula Erichson 1835
Creators: name: Pacheco, Thaynara L.
name: Wipfler, Benedict
name: Monné, Marcela L.
name: Ahrens, Dirk
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Melolonthidae
Symmela
Symmela longula

description: Symmela longula Erichson, 1835
(Figures 16, 29 (c), 30(o))
Symmela longula Erichson, 1835: 265 (original description); Blanchard 1850: 85 (catalogue); Burmeister 1855: 135 (revision); Harold 1869: 1126 (checklist); Frey 1973: 322 (key); Evans 2003: 48; Evans and Smith 2005: 30, 2007: 31, 2009: 31 (checklist)
Symmela angustula Moser, 1919: 7 (original description); Frey 1973: 323 (key); Evans 2003: 47, Evans and Smith 2005: 29, 2007: 29, 2009: 30 (checklist), syn. nov.
Type material examined
Lectotype (S. longula, here designated): ♂ ‘ longula Er. Brasil Setl./ 24985/ Typus’ (ZMHB). Paralectotypes (S. longula): 6 ♂♂ ‘ Brasil Sello Nr. 24985/ Typus/ Symela [sic!] longula Er. ’ (ZMHB), 1 ♂ ‘24985/ [from old collection catalogue: Brasil Sello]’ (ZMHB), 5 ♀♀ ‘ Brasil Sello Nr. 24986/ Typus/ Symela [sic!] longula Er. ’ (ZMHB). Lectotype (S. angustula, here designated): ♂ ‘Caraça (Minas Geraez) Bresil / Symmela angustula Type ♂ Mos/ Typus’ (ZMHB). Paralectotype (S. angustula): 1 ♀ ‘Caraça (Minas Geraez) Bresil / Symmela angustula Type ♀ Mos/ Typus’ (ZMHB).
Additional material examined
1 ♂ ‘Brasil’ (ZMHB), 1 ♀ ‘ Brasilia New Friburgo b. Beske’ (ZMHB), 1 ♀ ‘24991/ Brasil Virm./ n. sp./ Berlin/ Symmela tenella Er. Det. G. Frey 1972 ’ (ZMHB), 2 ♂♂ ‘Brasilia/ Type / Symmela tenella Er. coll. Moser’ (ZMHB), 1 ♂ ‘ Brasil / type mgl./ Symela longula Er. / 77 Neotropical Sericini spec.’ (ZMHB), 8 ♂♂ ‘ Brésil Caraca P. Germain 2e Semestre 1884/ Muséum Paris ex Coll. Oberthür 1952’ (MNHN), 1 ♂ ‘ Brésil Rio Piracicaba P. Germain Fevrier 1885 / Muséum Paris ex Coll. Oberthür 1952’ (MNHN).
Redescription
Length: 4.8 mm. Elytral length: 3.1 mm. Width: 2.2 mm. Head blackish brown, shiny, with erect, sparse setae. Labroclypeus as wide as frons, subtrapezoidal; surface flat; plain, without an anterior concavity on each side; anterior margin straight, strongly reflexed, without a rim of 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: 1/4. Eyes evenly spherical, ratio of diameter/interocular width: 0.53. 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 bicoloured, dull but iridescent, blackish brown; 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 bent at middle, otherwise straight, behind anterior angles straight, 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 moderately dense, simple and fine, without well-defined impunctate areas. Scutellum without punctures.
Elytra bicoloured, yellowish brown in major part, margins blackish; 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 strongly convex.
Legs yellow. Ratio of length of metepisternum/metacoxa: 1/1.43. 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: 1/3.27; 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 twothirds 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, as long as second; 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, 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 16 (d,e).
Remarks
Lectotypes of Symmela longula and S. angustula are virtually identical in shape. Symmela nitida Erichson is very similar, but the parameres are slightly wider and less concavely curved laterally.
description: Published as part of Pacheco, Thaynara L., Wipfler, Benedict, Monné, Marcela L. & Ahrens, Dirk, 2022, The genus Symmela Erichson, 1835 (Coleoptera, Scarabaeidae, Sericini): taxonomy and phylogenetic analysis, pp. 607-705 in Journal of Natural History 56 (9 - 12) on pages 656-659, DOI: 10.1080/00222933.2022.2084649, http://zenodo.org/record/7012522