Cretanapleus seideli Simon Prazak & Lackner, 2023

Simon Prazak, Jan, Fikacek, Martin, Prokop, Jakub & Lackner, Tomas, 2023, Under the Cretaceous bark: Fossil evidence for the ancient origin of subcortical lifestyle of clown beetles (Coleoptera: Histeridae), Arthropod Systematics & amp; Phylogeny 81, pp. 439-453 : 439

Cretanapleus seideli Simon Prazak & Lackner sp. nov.

Type material.

Holotype specimen (1409/E), unknown sex, Northern Myanmar, inclusion in burmite (ca. 99 Ma), amber piece clear, 15 ×6× 2 mm, with small pieces of debris.

Description.

Measurements. Head width: 0.14 mm, width between anterior pronotal angles: 0.175 mm, width between posterior pronotal angles: 0.4 mm, pronotal length: 0.21 mm, elytral length: 0.38 mm, elytral width (across widest point): 0.46 mm. - Body regularly round, convex, cuticle brown to black, covered with white debris coating. Body margins dorsally explanate. Elytra with punctures (diameter 10 microns) separated by their diameter. Pronotum with irregular weak longitudinal rugae. - Head. Frontoclypeal area laterally depressed, almost constricted. Frontal stria carinate, widely interrupted medially, slightly continuous to clypeus. Frontal surface laterad of frontal stria forming a depression fit to receive antennal scape in repose, pressed against outer margin of frontal stria. Clypeus anteriorly elevated with large punctures. Labrum dorsally with depressions, with a pair of long prominent setae. Right mandible bidentate with a prominent acute subapical tooth, inner margin of left mandible not visible. Terminal maxillary palpomere elongate, apically acute, slightly flattened. Antennal scape long and robust. Shape of the scape coincident with frontal carina. Pedicel as long as antennomeres 3-6 combined. Antennomeres 3-8 short. Antennal club round, with two apparent straight annuli. Eyes not visible. - Thorax. Pronotal margins narrowing anteriorly; anterior angles acute. Lateral and anterior margins explanate. Median part of frontal disc punctuate, convex with irregular longitudinal rugae. Posterior margin subungulate. Scutellum minute, triangular. Elytra apically truncate. Lateral and basal elytral margins distinctly explanate. Elytral suture elevated. Elytra punctuate at least medially (punctures separated by their diameter); rest of elytral surface covered with debris. Dorsal striation not discernible. Elytral epipleuron unusually wide with two protuberant costae on basal half. Epipleuron largely conceals metepisternum. Prosternal process rectangular, medially depressed. Prosternal lobe short with distinct margin and with antennal fissures laterally. Apex of prosternal lobe keel-like, elevated. Antennal cavity located near procoxa, deep, closed anteriorly. Mesoventrite transverse, 4x wider than long. Meso-metaventral suture invisible. Meso-metaventral stria carinate, anteriorly arcuate. Anterolateral corners with distinct round depressions. Metaventrite with delicate sparse punctures. Lateral metaventral stria complete, carinate. Metaventral disc convex. Metepisternum largely concealed by elytral epipleuron, with rugose punctuation. - Abdomen. First visible abdominal sternite with large punctures separated by their diameter. Pygidium with similarly patterned punctures. Other abdominal segments inflexed and covered with debris, unobservable. - Legs. Profemur with a weakly developed groove for protibial reception. Protibia moderately broad, with a costa along inner margin and slightly thickened along the outer margin, creating a tarsal groove. Outer protibial margin with a dense row of short setae diminishing in size basally, a row of short slender setae also present on the inner margin. Protibial spur tiny. Terminal protarsomere as long as tarsomeres 2-4 combined, claws 1/3 of terminal tarsomere length. Mesotibia slenderer, with a row of short slender setae both on outer and inner margin. Mesotibia with a shallow groove for mesofemoral reception. Mesotarsus similar to protarsus. Metafemur with a groove for metatibial reception, otherwise hind leg identical to middle leg.

Taxonomic assignment.

Cretanapleus seideli can be clearly placed in the Dendrophilinae based on the prosternum with a short prosternal lobe with antennal fissures laterally. We further place this species in the monophyletic tribe Anapleini ( Zhou et al. 2020), as defined by Olexa (1984), based on protibial characters: protarsal groove with distinctly elevated margins, outer protibial margin simple, devoid of teeth or denticles, with a simple row of setae (Fig. 3C, D ). However, C. seideli differs from the only extant genus of the tribe, Anapleus Horn, 1873, in several significant characters: presence of frontal stria (absent in Anapleus , Fig. 3G, H ), deep and closed antennal cavity (shallow and widely open in Anapleus ), and strongly emarginated lateral body margins (Fig. 3G , rounded in Anapleus ). Our phylogenetic analyses confirmed the placement of C. seideli in Anapleini (Fig. 5 ).

Etymology.

We dedicate the species to Dr. Matthias Seidel (Naturhistorisches Museum, Vienna, Austria) who introduced the first author of this paper to the study of fossil beetle inclusions.

Without tribal placement

Genus Yethiha Caterino, 2021

Figures

Figure 3. Cretanapleus seideli Simon Prazak & Lackner, gen. & sp. nov. (A, B, C, E, G) and Anapleus sp. (Turkey; D, F, H; SEM micrographs). A dorsal view; B amber specimen; C - D protibia; E - F ventral view; G - H frontal view.

Figure 5. Maximum parsimony analysis of the position of known fossil species of the Histeridae. A the complete tree showing the position of the fossils and the current subfamily classification of the lineages; B Dendrophilinae part of the tree with mapped characters; C Histerinae part of the tree with mapped characters. Bold taxa = fossils, red taxa = fossils described in this paper. For characters see Zhou et al. (2020).