Lithostomatini Kolibac & Huang, 2008, 1906

Kolibac, Jiri, 2013, Trogossitidae: A review of the beetle family, with a catalogue and keys, ZooKeys 366, pp. 1-194 : 77-78

† Tribe Lithostomatini Kolibac & Huang, 2008

Lithostomini Kolibáč, J. & Huang, D.-Y. 2008: 142 (as). Bouchard, P. et al. 2011: 57 (emendation to Lithostomatini )

Type genus.

Lithostoma Martynov, 1926 [by monotypy and author’s designation]

Kolibáč, J. & Huang, D.-Y. 2008: 142. Yu, Y. et al. 2012: 250

Remarks.

This fossil differs from all other Mesozoic Trogossitidae described to date. If Martynov (1926) interpreted the shapes of the head and antennal segments well, it is the first known member of Trogossitidae without a distinct antennal club and with the head narrowed towards its base. The following features of Trogossitidae appear in the fossil: (1) general shape and size of body, (2) distinctly flattened sides of pronotum and elytra, (3) double rows of punctures/tubercles among elytral carinae, (4) robust bidentate mandibles, (5) extremely large scapus, and (6) dilated antennal segments with what are perhaps sensorial fields in the enlarged parts of each segment. The classification within Trogossitinae is based on the presence of the sensorial fields in the enlarged parts of the antennomeres alone. Small tubercles occurring in pronotum and elytra are known in trogossitine genera Calitys and Phanodesta only; no peltine representative possesses such structures. The tribe differs from the recent and fossil members of Trogossitinae in broadly oval body (this occurs in some Gymnochilini only), pronotum narrowed anteriad, antennae without conspicuous club and asymmetrical segments in flagellum, head narrowed towards base. The shape of antennal segments 10 and 11 is unknown because they are missing (only a trace of segment 10 is visible). The antennae may be only 10-segmented with the last segment enlarged (as in e.g. Egoliini ). The new tribe is probably isolated from other tribes of Trogossitinae and may be considered a sister group to them. The ventral part of the fossil is unfortunately unknown, so a classification of Lithostoma remains uncertain, chiefly based on the distinctly enlarged scapus.

On the other hand, the concept of Lithostomatini was justifiably called into question by Yu et al. (2012) who argued that insufficient morphological information existed for the establishment of a higher taxon.