Ancyrona eocenica, Schmied, Heiko, Wappler, Torsten & Č, Ji Ř Í Kolibá, 2009

Schmied, Heiko, Wappler, Torsten & Č, Ji Ř Í Kolibá, 2009, A new bark-gnawing beetle (Coleoptera, Trogossitidae) from the middle Eocene of Europe, with a checklist of fossil Trogossitidae, Zootaxa 1993, pp. 17-26 : 18-20

Ancyrona eocenica sp. nov.

(Figs. 1A, B, C)

Cassidinae gen. et sp. indet. Wappler, 2003a, pl. 13, fig. i, p. 110, fig. 75.

Holotype: PE_2000/475, LS, completely preserved, dorsal side visible. Deposited in the Eckfeld insect collection at the NHMM, Mainz.

Type locality and horizon: Eckfeld Maar near Manderscheid; middle Eocene, middle Lutetian, ELMA Geiseltalian, MP 13, 44.3 ± 0.4 Ma ( Mertz et al. 2000).

Description: Body length 2.66 mm, width 1.63 mm, distance between eyes 0.34 mm, pronotal length 0.55 mm, pronotal width 1.41 mm (fragmentary length), elytral length 1.83 mm, width of compressed part of elytra 0.16 mm. Dorsal surface black-brown; head, pronotum, and elytra conspicuously and regularly punctate. Pubescence of body not visible.

Two small apical teeth oriented in horizontal axis, with one tooth visible on right mandible; frontoclypeal suture present; compound eyes large, exopthalmic, not emarginate (Fig. 1C). Pronotum transverse, twice as FIGURE 1. A, B, C: Ancyrona eocenica sp. nov. (PE_2000/475, LS): (A) Holotype in dorsal view, (B) camera lucida drawing of the holotype, (C) detail of the head, showing details of the mandible (M) and fragmentary preserved parts of the first antennal segments (Ant). D: Ancyrona vicina Léveillé, 1899 “ Kamerun, Col. Kraatz, Grouvelle det.” (DEI, ZALF); general habitus. E: Ancyrona diversa (Pic, 1921) “ Korea Prov. Gang-von, district On-dzong, Kum-gang san, near hotel Gon-song, 250 m; 4 August1975, leg. J. Papp et A. Vojnits”; general habitus. F: Peltis ferruginea (Linneaus, 1758) (ZFMK, Bonn); detail of the head; black arrows indicating the distinctly extended corners of the pronotum. G: A. diversa (Pic, 1921) ; detail of head and pronotum. Scale bars: A–C, 1 mm. E–G 0.5 mm.

wide as head, anterior margin weakly concave, anterior corners not distinctly projecting, posterolateral corners rounded, posterior margin straight and as wide as elytra. Scutellum small, semicircular. Elytral humeri evenly rounded. Elytra regularly punctate, with approximately ten rows of punctures and ten carinae. Dorsal lateral margins of elytra flattened along entire length of elytra.

Differential diagnosis: The new species differs from recent species of Ancyrona in the following combination of characters: (1) minute body (2.66 mm), (2) anterior margin of pronotum weakly concave, (3) anterior corners of pronotum not distinctly developed, and (4) body broadly oval.

Etymology: The specific epithet is taken from the Greek eos, referring to the Eocene age of the fossil.

Comments: The diverse genus Ancyrona (~ 50 described and many undescribed species) is widespread, extending from Africa south of the Sahara across to Madagascar, and throughout southeast Asia to Japan and east Siberia, New Guinea, and northern Australia. One species ( A. japonica Reitter, 1889 ) also occurs in Europe ( Bulgaria, Hungary, and Slovakia). Distribution records in South America (two species reported) are dubious and should be double-checked. Body size varies from 3 to 8 mm; dorsal surface is covered by wax scales, thick setae, fine hairs, or is glabrous; anterior margin of pronotum is emarginate (concave), anterior corners are more or less projecting; eyes exopthalmic; joints of antennal club rounded to serrate; body rounded or weakly elongate.

Kolibáč (2007) divided Ancyrona into five species groups based on common body habitus and distribution rather than phylogenetic affinities. Thus, there is inherent difficulty in classifying A. eocenica sp. nov. in any of these groups due to a lack of sculpture and antennae in the fossil form.