Symmela 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

description: Symmela Erichson, 1835
Symmela Erichson, 1835: 261 (original description); Blanchard 1850: 84 (catalogue); Burmeister 1855: 131 (revision); Harold 1869: 1126 (checklist); Dalla Torre 1912: 77 (catalogue); Blackwelder 1944: 220 (checklist); Frey 1973: 316 (key); Evans 2003: 47; Evans and Smith 2005: 29, 2007: 29, 2009: 30 (checklist); Ahrens 2006: 136 (phylogenetic position)
Type species
Symmela instabilis Erichson, 1835 (by subsequent designation; Evans 2003).
Diagnosis
Body relatively small (<7 mm), colour variable from black to yellow, often bicoloured; dorsal surface always glabrous (Figures 1, 3 and 8). Antenna composed of eight antennomeres, club short and composed of three lamellate antennomeres (Figure 30 (d)). Placoid sensilla on antennal lamellae round and elongate (Figure 14 (a)). Labrum ventrally with one or two longitudinal rows of setae (Figure 14 (b)). Mandibles fully developed (Figure 14 (c,d)). Galea (maxilla) with strong teeth, maxillary palps short, as long as maxilla (Figure 14 (e,f)). Anterior margin of mentum weakly sinuated (Figure 14 (g)). Labial palps with three palpomeres; anterior margin of labium weakly concave (Figure 14 (g)). Elytral base: Figure 14 (h) (for more detailed character coding, see Ahrens 2006). Hind wing: Figure 14 (o). Mesonotum: Figure 14 (n). Meso and metafurca: Figure 14 (i). Abdomen without lateral carina (Figure 14 (j), arrow); penultimate ventrite without suture to penultimate tergite (Figures 2 (b), 4 (a), 5 (b), 6 (b), 9 (b), 11 (b), 12 (b), 14 (j) and 32(l))), sometimes ventrites medially along the midline shorter (Figure 14 (p)). Protarsi in males often but not always widened, and protarsal claws asymmetric (Figure 32 (d,f)). Aedeagus including parameres symmetrical (Figure 14 (l,r)), endophallus often strongly and completely (or at least in apical portion) sclerotised (Figure 14 (k,m)), phallobase mesoventrally membraneous (Figure 14 (q,r)); parameres setose (Figure 14 (m)).
Sexual dimorphism is well developed in most of the known species: the pygidium in females is usually less convex or flat, while in the male it is well convex. Furthermore, the protarsomeres are generally curved and/or enlarged in the male (Figure 32; see species descriptions for more detail), and the protarsal claws are sometimes asymmetrical. In contrast to the state in females, protarsal claws are always symmetrical while protarsi are straight, elongate and narrow. However, females of many species are still unknown.
Remarks
Frey (1973) formally erected an additional subgenus of Symmela, Sayloria Frey, 1973 to accommodate Astaena bicoloripes Saylor, 1946, which was recently elevated to the level of a separate genus (Pacheco et al. 2021). All other Symmela species were not formally treated as belonging to the subgenus Symmela by Frey (1973).
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 615-616, DOI: 10.1080/00222933.2022.2084649, http://zenodo.org/record/7012522