Electroxylita chronographica, Alekseev & Bukejs, 2021

Alekseev, Vitalii Igorevich & Bukejs, Andris, 2021, Fossil Melandryidae (Coleoptera: Tenebrionoidea) from Eocene Baltic amber of the Sambian peninsula: new genus, six new species, new records and key to described taxa, Zootaxa 4965 (1), pp. 142-166 : 144-146

publication ID	https://doi.org/ 10.11646/zootaxa.4965.1.7
publication LSID	lsid:zoobank.org:pub:1F5BE28F-C8B5-47FF-8A3F-68B5BC40BD6F
DOI	https://doi.org/10.5281/zenodo.4723241
persistent identifier	https://treatment.plazi.org/id/B57C1F27-BF2F-4A19-A45E-A3F3E076626C
taxon LSID	lsid:zoobank.org:act:B57C1F27-BF2F-4A19-A45E-A3F3E076626C
treatment provided by	Plazi
scientific name	Electroxylita chronographica
status	sp. nov.

Treatment

Electroxylita chronographica sp. nov.

( Figs. 1 View FIGURE 1 , 8A View FIGURE 8 , 9A View FIGURE 9 )

Type material. Holotype: No 7517 [ KRAM] (ex. coll. Jonas Damzen JDC 9156), “* Holotype / Electroxylita / chronographica sp. nov. / Alekseev et Bukejs des. 2021” [red handwritten label]; adult, male. Almost complete beetle inclusion (right meso- and metatarsus as well as basal portion of left protibia and apical portion of left profemur are missing) with partially exposed apical portion of aedeagus; included in a flat, transparent, orange amber piece with approximate dimensions of 27 mm × 13 mm and a maximum thickness of 4 mm; preserved without supplementary fixation. Organic syninclusions: some small detrital particles.

Type stratum. Baltic amber from Eocene amber-bearing blue Earth layers, mostly Bartonian age is interpreted for the extinct central European resin-producing forests ( Bukejs et al. 2019).

Type locality. Yantarny settlement (formerly Palmnicken), Sambian (Samland) Peninsula, Kaliningrad Region, Russia .

Description. Measurements: body length including exposed abdominal tergites about 5.1 mm, body maximum width 1.5 mm; pronotum length 1.0 mm, pronotum maximum width 1.5 mm; elytra length 3.5 mm, elytra maximum width 1.5 mm.

Body elongated, slightly convex dorsally; dark, unicolorous. Dorsal surface evenly punctured and covered with fine, decumbent, conspicuous pubescence.

Head inflexed downwards, almost invisible in dorsal view; frons and vertex slightly convex. Fronto-clypeal suture apparently absent. Labrum strongly transverse. Compound eyes large, entire, slightly prominent, oval, vertical diameter about 1.5× as transverse diameter; facets fine, without intrafacetal setae; interocular distance at upper margin of eyes approximately equal to vertical diameter of one eye. Apical labial palpomere triangular, pointed. Maxillary palpi about 0.3× as long as antenna; 4-segmented: palpomere 1 cylindrical, 3× longer than wide; palpomere 2 and 3 equal in length, subquadrate; palpomere 4 large, broadly cultriform, about 3.0× longer than wide, distinctly wider than previous palpomeres. Ratio of relative lenghts of maxillary palpomeres 1–4 = 4:2:2:11. Antennae 11-segmented, filiform, inserted between and close to anterior inner margin of eyes; short, reaching posteriorly to elytral base; antennomeres 3–10 equal in size, conical, elongate, about 2.6× longer than maximum wide; antennomere 11 narrowly ovoid with pointed apex. Ratio of relative lenghts of antennomeres 1–11 = 10:7:8:8:8:8:8:8:8:8:11.

Pronotum transverse, 1.5× wider than long, widest in posterior one-third; sparsely covered with small punctuation bearing decumbent hairs, distance between punctures equal to 3.0–4.0× diameter of one puncture. Pronotal base closely associated with elytral base, disc without impressions. Anterior pronotal margin arcuate; posterior margin slightly wider than elytral anterior margin, weakly bisinuated, finely but distinctly margined; lateral margins rounded, converging anteriad and narrowed posteriad. Lateral pronotal carina present, complete. Anterior pronotal angles absent; posterior angles obtuse. Notosternal sutures distinct, flat. Prohypomera concave posteriorly, densely punctate, distance between punctures equal to 0.2–0.3× diameter of one puncture. Anterior portion of prosternum about 0.5× as long as diameter of procoxal cavity. Procoxal cavities externally open, with fissure (protrochantins visible). Scutellar shield transverse, about 2.0× as wide as long.

Elytra elongate, about 2.3× longer than wide, widest in anterior one-third, subparallel-sided in anterior twothird, gradually narrowed in posterior one-third; elytral apices rounded separately; elytral punctuation irregular, small and sparse, similar to pronotal punctuation. Elytral striae absent except for fine line-like sutural stria in posterior half of elytron. Metathoracic wings not visible. Epipleura narrow, widest basally and gradually narrowed posteriad, reaching abdominal ventrite 1. Metepisternum with subparallel lateral sides, about 6.0× longer than maximum wide. Metaventrite densely covered with small punctuation, distance between punctures approximately equal to diameter of one puncture.

Legs slender, long. Procoxae contiguous, egg-shaped, projecting below prosternum; mesocoxae rounded, narrowly separated; metacoxae elongate oval, transverse. Femora flattened. Tibiae subcylindrical, punctate, almost straight, slightly dilated apically, subequal in length to femora, with two short spurs of equal length and fringe of short bristles apically; metatibial spurs slightly shorter than metatibial width at apex. Tarsi long, metatarsus nearly as long as metatibia; tarsal formula 5-5-4; penultimate tarsomere of fore leg bilobed, penultimate tarsomere of mid leg widened, penultimate tarsomere of hind leg conical. Protarsomeres 2 and 3 widened. Metatarsomere 1 about 0.5× as long as metatibia. Ratio of relative lengths of metatarsomeres 1–4 = 3:1:0.5:1. Pretarsal claws simple, symmetrical.

Abdomen with five visible ventrites; ventrite 5 with rounded apical margin; relative length ratios of ventrites 1–5 equal to 4:4:3:3:2 (medially).

Apical portion of aedeagus as in Fig. 8A View FIGURE 8 .

Etymology. The epithet of the new species (Greek adjective chronographicus, meaning “time recording or writing”) refers to ancient origin and possible use of the fossil in evolutionary analysis and in the molecular clock calibration.