Jurodes shef, Yan & Strelnikova & Ponomarenko, 2021

Yan, Evgeny V., Strelnikova, Olesya D. & Ponomarenko, Alexander G., 2021, Jurodidae (Coleoptera: Archostemata) from Transbaikalia: new findings and redescription of type material, Palaeoentomology 4 (6), pp. 604-613 : 609-611

Jurodes shef sp. nov.

( Fig. 6 )

Material. Holotype PIN, 5340/1232, part and counterpart of body, right antennae and hind legs are missing . Paratypes PIN, 5340/1243 and 3720 parts, and counterparts from the same locality .

Etymology. After Professor A.P. Rasnitsyn, noun, informal degree meaning “laboratory chief” in Russian.

Diagnosis. J. shef resembles J. minor in its habitus and size, but differs in the elongated, almost triangular head, in contrast to all other known jurodids not constricted at the level of the clypeus and labrum. The eyes are oblique and the gular plate is very narrow, in its narrowest region not wider than the eyes. The pronotum displays a single median depression and not an H-shaped protuberance, like other jurodids including Sikhotealinia .

Type locality and horizon. Khasurty locality, Lower Cretaceous (Berriasian-Hauterivian), Gusinoe Ozero Group, Russia .

Description. Small beetle. Head notably longer than pronotum, triangular, widest behind eyes, lacking neck constriction. Labrum transverse, rectangular, very short, half as long as clypeus. Mandibles sickle-shaped, projecting very slightly beyond anterior labral margin; outer margins fully covered by labrum and clypeus. Clypeus trapezoid, posterior margin slightly concave, slightly narrower than anterior margin of frons.

Frons with subtriangular depression medially at its anterior margin and a deep median U-shaped depression reaching the cephalic midlength; distinct supraantennal protuberances (P1) present and distinct carina running along inner ocular margins. Antennal insertions visible from above, located near anterolateral angles of frons, closer to external cephalic margin than to each other. Antennae filiform, reaching elytral bases posteriorly; antennomeres 2 to 9 widening anteriorly, subequal in shape; pedicellus not smaller than antennomeres; antennomeres without fine basal sulci. Eyes as long as combined length of two antennomeres, weakly protruding laterally. Temples straight, slightly shorter than eyes. Gula as wide as labrum; gular sutures distinct, almost parallelsided, only slightly narrowing anteriorly; posterior gular margin rounded, anterior margin concave. Submentum as long as gula, parallel-sided. Labial palpi 3-segmented; first palpomere rectangular, two times as long as wide, second palpomere square, apical one semioval.

Pronotum subtrapezoid, carinate, angles rounded, anterior margin 0.3 times shorter than posterior one. Median portion of pronotal disc bears longitudinal depressions at anterior and posterior margins, connected by thin median furrow. Mesoscutellar shield triangular, small, as long as one antennomere. Elytra carinate, leaving apical tergite exposed; with at least 11 rows of punctures.

Mesocoxae separated by at least half of their length by anteromedian process of metaventrite. Metaventrite with longitudinal median ridge (discrimen); not widening posteriorly; posterior intercoxal process very short, leaving metacoxae contiguous. Metanepisternum parallel-sided, as wide as mesofemora. Abdomen with clearly visible laterosternites.

Measurements (in mm). Body length, 3.6, width, 1.5, elytral length, 2.3, elytral width, 0.9.

Remarks. The wing veins are not distinct, but the costal bar is well visible ( Fig. 6B ).

Figures

FIGURE 6. Jurodes shef sp. nov. A, Holotype PIN, 5340/1232, wetted with 96% ethanol. B, Interpretative line drawing. Abbreviations: alc, alacrista; clp, clypeus; cs.b, costal bar; gul, gular plate; lb.p, labial palpus; lbr, labrum; lts, laterosternite; msi, median scutal impression; mta, metanepisternum; P1, supraantennal protuberance; pdl, pedicellus; scl2, mesoscutellum; s.lg, longitudinal suture; smt, submentum; s.stpl, sternopleural suture; tmp, temple; tr3, metatrochantin. Scale bars = 1 mm.