Coleopsis archaica Ki rejtshuk, Poschmann and Nel, 2014

Schaedel, Mario, Yavorskaya, Margarita & Beutel, Rolf, 2022, The earliest beetle † Coleopsis archaica (Insecta: Coleoptera) - morphological re-eva luation using Reflectance Transformation Imaging (RTI) and phylogenetic assessment, Arthropod Systematics & amp; Phylogeny 80, pp. 495-510 : 495

Coleopsis archaica Ki rejtshuk, Poschmann and Nel, 2014

? Coleoptera .? Tshekardocoleidae Poschmann and Schindler 2004, p. 304, fig. 7

Tshekardocoleidae gen. et sp. indet. Brauckmann 2007, p. 191, fig. 17

Coleopsis archaica Kirejtshuk, Poschmann and Nel 2014 in Kirej-tshuk, Poschmann, Prokop, Gar rouste and Nel 2014, p. 6, figs.1,4

Coleopsis archaica Kirejthuk and Nel 2016, p. 71, figs. 1-5

Coleopsis archaica Kirejtshuk 2 020, p. 10, figs. 2 A-C

Holotype (the only specimen).

ZfB 3315, Zentrum für Biodokumentation, Schiffweiler, Germany.

Redescription.

General features. The slender beetle is 7.8 mm long (inc luding mandibles and elytra) and reaches its maximum width of 2.5 mm slightly anterior to the posterior third of the body. The anterior part of the body with the prognathous head and the short and transverse prothorax is unusually short in relation to the remaining body (pterothorax + abdomen), which comprises ca. 80% of the total length. The elongate elytra reach beyond the abdominal apex (Fig. 1 ). The dorsal surfaces of the head and the pronotum display a pattern of fine cuticular tubercles. - Head capsule. The head is distinctly prognathous, about as broad as long, with rounded postocular temples and a short and moderately constricted neck region (Fig. 2A ). Vestiges of dorsal ecdysial lines, the frontal and coronal sutures, are not recognizable. The head capsule is slightly narrowing anterior to the compound eyes. Dorsal protuberances (see Beutel et al. 2008) are visible but rather inconspicuous (best visible in the black-and-white height maps; Fig. 2A, B ). The compound eyes are large and strongly convex, strongly protruding laterally. Ocelli are not present. Antennal insertions, tentorial pits, maxillary grooves, and gular sutures are not visible. - Labrum. The labrum is well-developed, broad, with rounded anterolateral angles and lacking an anteromedian emargination. - Antennae. Not preserved. - Mandibles . The mandibles are moderately sized, exposed laterad the labrum, laterally evenly curved, and distinctly protruding beyond the anterior labral edge, with a single visible apical tooth. - Maxillae . The maxillary body is likely visible on the right side, posterolaterad the labrum (Fig. 2A , 3A ). A part of the maxillary palp is recognizable on both sides. - Labium. A large plate-like structure, likely comprising the mentum and prementum, is visible. It has a laterally rounded anterior margin and a seemingly very distinct, straight hind margin (possibly congruent with the anterior margin of the frons). An indistinct, straight transverse suture is present on the anterior third. The labial palps and endite lobes are not visible. - Prothorax. The transverse pronotum is more than three times as wide as its length along the midline. It is very slightly convex anteromedially and nearly straight posteriorly. Laterally it is strongly explanate, forming thin lateral duplicatures with a coarsely serrated margin. The anterolateral edges are distinctly projecting anteriorly. Posterolateral angles are indistinct or absent. The outlines of the small, rounded and medially separated procoxae are recognizable. A broad postcoxal bridge is obviously missing, suggesting posteriorly open procoxal cavities. The parallel--sided profemora are visible between the posterior pronotal margin and the concave anterolateral elytral edge. Other distal parts of the legs (e.g. pro-, meso- or metatibiae) (depicted in Kirejtshuk et al. 2014, fig. 1) are not recognizable. - Mesothorax. The large and exposed triangular scutellar shield is about as long as the pronotum. Ovoid and slightly oblique mesocoxae are indistinctly visible, slightly separated medially. Other parts of the mesothorax except for the elytra are not recognizable. - Elytra. The elytra are long and slender, comprising about 80% of the total body length, and nearly 5x as long as their maximum width. The shoulder region is distinctly retracted, almost to the level of the posterior edge of the scutellar shield, thus forming a distinct concavity of the anterior elytral edge. Broad explanate lateral flanges are present instead of typical inward folded epipleurae. They apparently cover the posterior body in a loose tent-like manner without forming a tightly sealed subelytral space. Posteriorly they distinctly reach beyond the abdominal apex. Several distinct longitudinal veins with a non-parallel-arrangement are present, comprising C along the lateral edge, a rather indistinct Sc which almost reaches the elytral apex, an equally long and distinct vein (either representing R or R+MA), a long CuA which traverses the elytra from the anterolateral region (almost at the anterior edge of R) almost to the elytral tip, and a single anal vein (A) about 1/3 as long as the elytron. All longitudinal veins are unbranched. Several shorter and rather indistinct longitudinal veins with unclear homology are present on the posterior 1/3, designated tentatively here as intercalary veins (secondary [or supplementary] longitudinal veins). Cross veins are missing. Window punctures are recognizable between CuA and A on the anterior 1/3 of the elytra but indistinct, arguably an artefact caused by the strong compression of the fossil. - Metathorax. The indistinctly visible meso- and metacoxae indicate that the metathorax is slightly longer than the mesothorax, but the bord er between both segments is not recognizable. The metathorax appears almost parallel-sided, only slightly widening posteriorly as suggested by the position and outline of the coxae. The anapleural suture and the pleural elements are not recognizable, and a median discrimen, a transverse ridge and an exposed metatrochantin are also not visible. The indistinctly recognizable metacoxae are transverse. An indistinct oblique line, likely the posterolateral edge, tentatively suggests that the mesal metacoxal portion was distinctly projecting into the anterior abdomen. Metacoxal plates are not recognizable and are probably missing. A triangular metatrochanter with rounded edges is visible. Distal parts of the hind legs are not preserved. - Hind wings. The rounded apical part of the membranous hind wings, clearly visible on the right body side (Fig. 1 ), distinctly projects beyond the elytral apex. The exposed apical wing portion does not show any trace of folding or rolling, and no veins are visible on this region. - Abdomen. The abdomen is evenly rounded laterally and tapering towards its sub-acuminate apex. It ends distinctly before the elytral apices. Individual sternites are not visible (in contrast to Kirejtshuk et al. 2014).

Updated species diagnosis.

Body medium-sized (7.8 mm total length), slender. Head prognathous. Eyes strongly protruding laterally. Prothorax short. Pronotum more than three times as wide as its length along the midline, with anterolateral processes distinct, and lateral portions distinctly explanate with coarsely serrated margin. Procoxae small, rounded and medially separated. Dorsal surface of head and pronotum with fine tubercles. Scutellar shield triangular and large. Elytra reaching well beyond abdominal apex. Elytral shoulder region emarginated, with distinct concavity. Elytra with broad explanate lateral flanges. CuA oblique, from anterolateral region almost to the elytral tip; single anal vein (A) about 1/3 as long as the elytron. Window punctures visible between CuA and A. Mesocoxae ovoid and slightly oblique. Metathorax slightly longer than mesothorax.

This diagnosis is explicitly stated as a species-level diagnosis. Since † Coleopsis is monotypic, as are †Coleo-pseidae (and † Coleopseoidea Kirejthsuk and Nel 2016), the diagnosis should only be used to distinguish further specimens from † C. archaica . It should not be arbitrarily split up into parts which then could lead future authors to include additional species into the (presently) monotypic taxonomic category, without providing an apomorphy-based argumentation or a phylogenetic analysis.

Figures

Figure 1. † Coleopsis archaica, holotype, ZfB 3315, microscopic images, coaxial cross-polarised light, multi exposure bracketing. A photograph of more complete side (part); B less complete side (counterpart) virtually projected onto the part (the counterpart is mirrored); C photograph of the counterpart. Abbreviations: A, Analis (anal vein); abd, abdomen; ce, compound eye; CuA, Cubitus anterior; edt, elytral distal tip; elc, elytral antero-proximal corner; elf, elytral flange; elpm, elytral posterior margin; hw, hind wing; iv, intercalary veins; leg 1, foreleg; pnlp, lateral process of the pronotum; pn, pronotum.

Figure 2. † Coleopsis archaica, holotype, ZfB 3315. A - C microscopic images, coaxial cross-polarised light, multi exposure bracketing. A detail of the head and prothorax region, part; B detail of the head and prothorax region, counterpart; C: detail of the left side of the mesothoracic region, part; D - G images derived from RTI imaging, the circular legends in the lower-left corners depict the convex half sphere used to calibrate the RTI setup under the same conditions as the images; D normal map representation of the part; E relative heights representation of the part; F normal map representation of the counterpart. Abbreviations: G relative heights representation of the counterpart. ce, compound eye; elm, elytral margin; elc, elytral antero-proximal corner; leg 1, foreleg; md, mandible; mxp, maxillary palp; pnlp, lateral process of the pronotum; ve, venter.

Figure 3. † Coleopsis archaica, holotype, ZfB 3315, drawings based on the photographs and the RTI images. A more complete side (part); B part and counterpart combined (counterpart mirrored); C counterpart. Abbreviations: A, Analis, anal vein; abd, abdomen; C, Costa; ce, compound eye; CuA, Cubitus anterior; cx 1 - 3, coxa of thoracic segments 1 - 3; edt, elytral distal tip; elc, elytral antero-proximal corner; elf, elytral flange; elpm, elytral posterior margin; fr, frons; h, head; hw, hindwing; iv, intercalary veins; lbr, labrum; leg 1, foreleg; md, mandible; mt, mentum; mx, maxilla; mxp, maxillary palp; pmt, prementum; pn, pronotum; pnlp, lateral process of the pronotum; R (+ MA?), Radius, possibly conjoined with Media anterior; Sc, Subcosta; scs, scutellar shield; tr 3, metatrochanter; ve, venter; wp, window punctures, exemplary, not limited to this area of the wing.