Pogonocherus minimus, Vitali, 2022

Vitali, Francesco, 2022, Two new Pogonocherus species (Coleoptera: Cerambycidae) from Baltic amber, Baltic Journal of Coleopterology 22 (1), pp. 103-110 : 104-105

Pogonocherus minimus n. sp.

( Fig. 1 , 4 )

Holotype. Baltic amber, “ Cerambycidae Lamiinae prob. Parmenops ”, ex coll. M. Veta, n° 210927, author’s coll. FS85BS53.

Differential diagnosis. Both specimens were identified as members of Lamiinae Pogonocherini due to the following combination of characters: frons vertical, small body size, scape without apical cicatrix and feebly club­shaped; antennae fringed; pronotal tooth conical, mesosternum not shortened and claws opposite.Among worldwide Pogonocherini ( Breuning, 1975) , clavate femora, furrowed mesotibiae, pronotum with lateral but without discal tubercles, and antennomere IV incurved and longer than III point out to the genus Pogonocherus .

Zang (1905) provided the first modern descriptions of fossil beetles: description and differential diagnosis of P. jaekeli are so precise that it is possible to compare this species with all congeners of the Recent, though we could not manage to directly observe the holotype. Accordingly, P. jaekeli is closely related to P. ovatus (Goeze, 1777) , P. decoratus Fairmaire, 1855 (which Zang already mentioned) and P. zubovi Danilevsky, 2015 , from which it differs in the elytra separately rounded at apex and without hair fascicles. Both characters are also present in the species described here.

Additional characters are the elytra with three feeble post­median dorsal ridges not reaching the apex, the humeral one reaching the humerus, the basal third crossed from humerus to suture by an oblique band of coarse punctures and erect setae

( Fig. 4 ) and finally, the pronotum without bulges but four dimples delimiting a square.

Pogonocherus minimus n. sp. is characterised by pronotum unpunctuated, elytra densely covered with a fine recumbent pubescence, regular rows of oblique setae and four regular rows of coarse punctures (pre­sutural one on the basal third; discal, pre­humeral and humeral ones on the basal two­thirds, the pre­humeral the longest). These characters are sufficient to separate this species from all fossil and extant congeners.

Description. Body length 2.3 mm. Habitus minute, stout.

Labium densely covered with long arched pubescence; frons parallel­sided, convex and sparsely covered with long erect setae, twice as long as those on the elytra; eyes strongly reniform and finely facetted; lower eyes­lobes transverse, barely shorter than genae; genae transversally ridged; vertex wide, covered with some erect setae as long as those on the elytra.

Antennae almost thick, a bit shorter than body (female), antennomeres I–VI internally fringed with sparse erect setae; scape almost club­shaped; pedicle twice as long as wide; antennomere III feebly bowed, one­eight shorter than scape; antennomere IV the longest, about one­fourth longer than scape; antennomere V about one­half of the previous; antennomere VI four­fifth as long as III, antennomeres VII–VIII equal two­fifth as long as III; antennomere proportions according to the formula: 3.4: 1.0: 3.0: 4.2: 2.4: 1.8: 1.2: 1.2: 1.6?:?:?.

Pronotum convex; apical margin finely furrowed; base with two transverse furrows; sides armed with a small obtuse conical tooth in the middle; surface with some sparse punctures at sides and on the base, covered with a dense fine uniform pubescence and some erect setae, as long as those on the elytra, on the base. Scutellum small, shaped as an equilateral triangle.

Elytra short (each elytron about twice as long as wide at base), ovoid, dorsally convex; humeri almost prominent; apices widely rounded; disc densely covered with a fine recumbent pubescence, four regular rows of coarse punctures (pre­sutural one on the basal third; discal, pre­humeral and humeral ones on the basal two­thirds, the pre­humeral the longest) and numerous sparse oblique setae; suture finely furrowed; lateral margin fringed with semi­recumbent setae.

Legs relatively short covered with a short pubescence and some semi­recumbent setae; femora club­shaped; protibiae straight; meta­ and mesotibiae sinuate; mesotibiae with pre­apical furrow; tarsi short; claws opposite.

Ventral side not observable.

Figures

Fig. 1. Pogonocherus minimus n. sp.

Fig. 4. From left to right, elytral structure of P. minimus n. sp., P. jaekeli Zang, 1905 and P. scutellaris n. sp. (proportions according to the respective body size).