Sinosoronia Zhang, 1992

Kolibac, Jiri, 2013, Trogossitidae: A review of the beetle family, with a catalogue and keys, ZooKeys 366, pp. 1-194 : 120-121

† Genus Sinosoronia Zhang, 1992 Map 12

Nitidulidae Zhang, J.-F. 1992: 333 [in Chinese], 336 [in English] (sub)

Type species:

Sinosoronia longiantennata Zhang, 1992 [by monotypy]

Kolibáč, J. 2006: 136 ( Trogossitidae incertae sedis). Kolibáč, J. & Huang, D.-Y. 2008: 145 ( Ancyronini ). Ponomarenko, A. G. & Kireichuk, A. G. (2005-2008): http://www.zin.ru/animalia/Coleoptera/rus/paleosy2.htm ( Peltidae ). Zhang, J.-F. 1992: 333 [in Chinese], 336 [in English]. Schmied, H. et al. 2009: 26

Remarks.

Sinosoronia might be related to another Mesozoic genus, Peltocoleops . The latter genus was described as " Cleroidea incertae sedis " ( Ponomarenko 1990) and classified within Lophocaterini by myself ( Kolibáč 2006). The two genera differ distinctly in the shape of the antennal club. This is compact and 3-segmented, with segments weakly asymmetrical in Peltocoleops but loose, 2- or 3-segmented, with segments distinctly asymmetrical in Sinosoronia . It is therefore suggested that the latter genus be classified within the tribe Ancyronini , which has corresponding features in recent representatives. The large, elevated eyes observed in Sinosoronia also support such a classification (according to Kolibáč and Huang 2008).

The "posterior femur" in the original description is probably the hind coxa. The long antenna with a loose club resembles that of species of the Ancyrona gabonica species-group, while a similar shape of the pronotum may be found in the colobicoides species-group. Such an extremely small size of body is not known in recent Ancyronini but occurs in an concurrently described species from the late middle Eocene ( Schmied et al. 2009). Apart from body size, the two species share large, elevated eyes and similar shape of pronotum. The time difference between these two very similar species is about 100 million years, much more than between the Eocene and the present time. Round body and body size might appear indicative of a group of the rentoniine genera. However, the body is much smaller (about 1 mm) and the antennae shorter with a symmetrical club in the rentoniins ( Kolibáč 2005). If the asymmetrical club is considered an apomorphy, Sinosoronia may well be an ancestor of Ancyronini rather than Thymalini (according to Kolibáč and Huang 2008).

Original description.

" Brown in colour. Head about as long as wide. Mandibles large but dentes indistinguishable. Eyes circular, expanded laterally but exterior margin ill-preserved. Antennae 1.2 times as long as head and pronotum together, several basal segments ill-preserved except for the thickened scape, each flagellum cylindrical, about twice as long as wide, club elongate, nearly one-third the length of antenna, slightly thickened apically. Pronotum 2.1 times as broad as long; anterior margin arched, its median part straight, curved forwards laterally, lateral margins arched, posterior margin sinuate, and closely connected to elytra. Scutellum about as long as wide. Elytra smooth, not striated, exterior and interior margins slightly arched, shoulder rounded, its terminal part distinctly exceeding apex of abdomen, each elytron 2.6 times as long as wide. Middle and posterior femora seemingly clubbed, both tibiae and tarsi absent. Total length 2.3 mm, width 1.3 mm. " ( Zhang 1992: 336.)

Distribution.

China: Shandong province; Mesozoic: Lower Cretaceous, Laiyang formation.

Species:

† Sinosoronia longiantennata Zhang, 1992; China: Shandong; Lower Cretaceous: Laiyang formation (varA)

Kolibáč, J. 2006: 136. Kolibáč, J. & Huang, D.-Y. 2008: 145. Ponomarenko, A. G. & Kireichuk, A. G. (2005-2008): http://www.zin.ru/animalia/Coleoptera/rus/paleosy2.htm. Schmied, H. et al. 2009: 26. Zhang, J.-F. 1992: 333 [in Chinese], 336 [in English]

Figures

Map 12. A distribution of the tribe Ancyronini.