Palaeocnopus densipunctatus, Alekseev, Vitalii I. & Grzymala, Traci L., 2015

Alekseev, Vitalii I. & Grzymala, Traci L., 2015, New Aderidae (Coleoptera: Tenebrionoidea) from Baltic and Bitterfeld amber, Zootaxa 3956 (2), pp. 239-257 : 250-251

Palaeocnopus densipunctatus sp. nov. Alekseev & Grzymala

( Figs. 21 , 25–27 )

Material examined. Holotype No. 420-6 [ CCHH], possible female (due to small eyes and short antennae) ( Fig. 22 ). The beetle inclusion is preserved in a polished piece of transparent amber with a yellowish shade and the amber piece is embedded in polyester resin. The syninclusions are represented by two trichomes and one phorid fly (Diptera) of length 1.2 mm. Paratype No. 217-1 [ CCHH], possible female ( Figs. 23–24 ). The beetle inclusion is preserved in a polished piece of transparent amber, yellow in color, without any further fixation. The amber piece is parallelepiped, with maximum length 16 mm and maximum width 9 mm. The syninclusions are represented by one well-preserved rove beetle ( Coleoptera : Staphylinidae : Omaliinae , aff. Phloeonomus Heer, 1839 , possibly an undescribed species, personal observation) of length 1.7 mm. Paratype No. AWI-107 [ CVIA], possible female. The beetle is included in a polished piece of transparent yellow amber, without any further fixation. The piece is flat, rounded, with maximum length 19 mm and maximum width 14 mm. The syninclusions are represented by two trichomes. Paratype No. 25-4 [ CCHH], possible female. The beetle inclusion is preserved in a polished piece of transparent amber with an orange shade. The amber piece is embedded in polyester resin. Paratype No. AWI-121 [ CVIA], possible female. The beetle is included in a polished piece of transparent yellow amber, without any further fixation. The piece is flat, with maximum length 23 mm and maximum width 17 mm. The syninclusions are represented by numerous trichomes.

Etymology. This species is named from a combination of Latin “ densus ”[dense] and Latin “ punctum ” [point, puncture], referring to the dense and coarse punctation on the vertex.

Type strata. Baltic Amber. Eocene.

Type locality. Russia, the Kaliningrad region, the Sambian [Samland] peninsula, Yantarny settlement [formerly Palmnicken].

Description. Length approximately 1.4–1.8 mm (No. 420-6— 1.75 mm; No. 217— 1.7 mm; AWI-107— 1.8 mm; No. 25-4— 1.5 mm; No. AWI-121— 1.4 mm); moderately convex, elongate; uniformly dark gray. Upper surface uniseriate, clothed with short pubescence. Body length 2.7× maximum body width. Elytral length 4.1× pronotal length.

Head. Eyes large, oval, hemispherical, coarsely faceted, adjacent to hind margin of head; interocular space wider than one ocular diameter; temples narrow; apical maxillary palpomere acute, triangular; apical labial palpomere oval. Vertex densely and coarsely punctate. Antenna ( Fig. 21 B) filiform, 11-segmented, sparsely pubescent; reaching basal third of elytra when folded backward; antennomere length ratios: 5-4-4-4-5-5-5-4-4-4-6.

Thorax. Pronotum transverse ( Fig. 21 A), widest basally; glabrous; coarsely and densely punctate; without visible pubescence; with two deep, well-defined sub-basal impressions, almost fused medially, and with two deep sub-triangular lateral impressions at anterior angles. Posterior angles rounded. Scutellum subquadrate, with posterior angles rounded. Elytron subparallel, moderately convex, with slight depression on disc; width 0.52× length; punctation irregular, coarse, dense. Elytral pubescence short, more visible laterally and apically. Metathoracic wings present.

Abdomen. Each abdominal ventrite with large deep punctures, punctures subequal to those on pro-, meso- and metathorax. Separation of abdominal ventrite I and abdominal ventrite II fine, but well-defined laterally, obsolete medially.

Legs. Metatarsomere I approximately equal in length to metatarsomeres II-IV combined.

Diagnosis. Palaeocnopus densipunctatus sp. nov. is characterized by the antennal ratios, the two deep subbasal pronotal impressions, and the densely, coarsely punctate vertex. Palaeocnopus densipunctatus sp. nov. differs from P. glabricornis and P. m ar a by the punctation of the head and pronotum, and from P. s ae t i c or n i s by the two separate pronotal impressions and absence of long pubescence on the antennae and elytra. Antennal ratios of this new species are similar to P. m a r a, but the presence of the two closed sub-basal pronotal impressions makes P. densipunctatus sp. nov. appear more similar to P. glabricornis .

Figures

FIGURES 21 – 24. Palaeocnopus spp. illustrations. 21) Palaeocnopus densipunctatus sp. nov. A. forebody, B. antenna; 22) Palaeocnopus saeticornis sp. nov. A. forebody, B. antenna; 23) Palaeocnopus glabricornis sp. nov. A. forebody, B. antenna; 24) Palaeocnopus mara sp. nov. A. forebody, B. antenna.

FIGURES 25 – 27. Palaeocnopus densipunctatus sp. nov. habitus photographs. 25) Holotype, lateral view; 26) Paratype (No. 217 - 1), dorsal view; 27) Paratype (No. 217 - 1), ventral view. Scale bars = 0.5 mm