Archelamprosomius, Bukejs, Andris & Nadein, Konstantin, 2015

Bukejs, Andris & Nadein, Konstantin, 2015, First fossil Lamprosomatinae leaf beetles (Coleoptera: Chrysomelidae) with descriptions of new genera and species from Baltic amber, Zootaxa 3931 (1), pp. 127-139 : 132

Archelamprosomius gen. nov.

Type species: Archelamprosomius balticus sp. nov.

Etymology. The name of this new genus is formed from the Greek ”arche“—” beginning“ and part of the name Lamprosomatinae ; gender masculine.

Included species. Besides the type species, the new genus includes Archelamprosomius kirejtshuki sp. nov.

Diagnosis. Vertex without medial longitudinal groove, frons without impression at inner margin of eye, lateral margins of pronotum straight and with carinate borders, prohypomera concave in posterior 1/3, epipleura strongly projecting in basal 1/3, legs weakly flattened.

Description. Body broadly oval, strongly convex; head barely visible from above, deeply protracted into prothorax; vertex slightly convex, without median groove; eyes entire, round-oval, small, convex; without groove at inner and upper margins of eye; pronotum narrowed anteriorly, all margins with carinate borders; posterior 1/3 of prohypomera strongly concave. Procoxal cavity open posteriorly. Scutellum small, triangular. Elytral punctures arranged in regular striae. Epipleura horizontal, with strongly produced and convex projection in basal 1/3. Abdomen with five visible ventrites, lateral margins of ventrites with very fine transverse folding. Legs short, femora and tibiae not strongly flattened and widened apically (in Archelamprosomius balticus sp. nov. metatibiae more distinctly widened apically), tibiae without longitudinal groove and with convex dorsal margin, metafemora extend to the abdominal ventrite 2.

Comparison. This new genus differs from the fossil genus Succinoomorphus gen. nov. in possessing a more convex body, without groove at inner and upper margins of eye, lateral margins of pronotum with distinctly carinate borders, prohypomera strongly concave in posterior 1/3, epipleura with strong and convex projection in basal 1/3, femora and tibiae weakly widened and not strongly flattened; dorsal surface of protibia convex, tibiae without groove, metafemora extending to the abdominal ventrite 2.

Archelamprosomius gen. nov. is similar to the recent Oomorphoides based on the strongly projecting basal third of the epipleura, but differs in the absence of a longitudinal groove on the vertex, frons without impression at inner margin of eyes (such impression are presents in Oomorphoides ), lateral margins of pronotum are nearly straight in lateral view (it is distinctly convex in Oomorphoides ), simple tarsal claws (appendiculate in Oomorphoides ), entire eyes (they have emarginate inner margin in Oomorphoides ). The new genus differs from Oomorphus in the absence of a longitudinal groove on the vertex, more protruding basal 1/3 of the epipleura, shorter and less flattened femora and tibiae. Combination of characters and differences from recent genera Oomorphus and Oomorphoides provide a basis for the establishment of this new genus, which has an intermediate position between these genera. The new genus differs from Asisia, Dorisina and Lychnophaes in the presence of entire eyes, without emargination; from Lamprosoma , Lamprosomoides , Oyarzuna and Scrophoomorphus it differs by having simple tarsal claws and entire eyes; and from Xenoomorphus in the presence of simple tarsal claws.