Thallisellites augustinusii Lyubarsky et Perkovsky, 2024

Lyubarsky, Georgy., Legalov, Andrei A., Vasilenko, Dmitry V. & Perkovsky, Evgeny E., 2024, Thallisellites augustinusii sp. nov. (Coleoptera: Erotylidae: Languriinae) from Priabonian Baltic amber, Ecologica Montenegrina 73, pp. 421-427 : 422-425

Thallisellites augustinusii Lyubarsky et Perkovsky sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:1DEE1B1E-2A2F-40FB-89D7-7DD1D28E6113

Figs. 1-2

Type material. Holotype: NHMD-644283, Yantarnyj, Baltic amber, late Eocene.

Description

Body elongate-oval, length 2.5 mm, maximum width ca. 1 mm, uniformly dark brown ( Fig. 1 С), dorsally with decumbent pubescence. Compound eye hemispherical, comparatively large, gently facetted. Length of compound eye equal to half head length. Facets small, approximately same diameter as head dorsal punctures. Dorsal punctures on head moderately large, intervening spaces narrower than puncture diameter. Frons weakly convex in dorsal aspect, punctured. Antenna short, slender, not extending beyond basal margin of pronotum. Antennal club weakly flattened. Antennomeres one, two, three slightly elongate; antennomeres four-seven subquadrate, antennomere eight slightly transversal ( Figs. 1A, 1B , 2C ). Basal antennomere slightly longer than and 0.3 as wide as antennomere two. Second antennomere slightly shorter than antennomere three. Third antennomere longer than antennomere four. Ninth antennomere as long as wide, penultimate antennomere slightly transverse, terminal antennomere elongate oval.

Pronotum transverse, ratio of pronotal width to length 1.6, without lateral teeth, covered with short pubescence. Anterior margin of pronotum slightly sinuous ( Fig. 1C ). Anterolateral angles of pronotum with small triangular tooth not protruding significantly anteriorly. Maximum width of pronotum across anterior angles. Lateral margins slightly converged posteriad, not serrated, not beaded, almost straight, weakly sinuated. Punctures moderately large, intervening spaces about as narrow as puncture diameter. Length of elytra 2.9 of pronotal length ( Fig. 2A ). Posterior margin sinuous, with large median lobe. Posterolateral angles right-angled. Basal groove poorly developed. Basal pits not present. Basal short longitudinal keel not present. Pro-, meso-, and metasternum strongly and densely punctured ( Fig. 2B ). Legs slender, tibia not dilated apically ( Figs. 2B, 2C ). Tarsal formula 5-5-5. Tarsomeres not lobed. Tarsomeres slightly elongate ( Fig. 2B ). Tarsomeres 1–3 about same length, terminal tarsomere the longest but shorter than combined length of tarsomeres one to four. Tarsal claws not serrated.

Scutellar shield transverse, ca. 2 times wider than long, moderately strongly punctured. Humeral teeth at base of elytron not present. Lateral margin of elytra slightly flattened and margined in dorsal view ( Fig. 1C ). Punctures of elytra moderately large, arranged into longitudinal rows ( Figs. 1C , 2A ), with intervening spaces about one puncture diameter; at least 14 rows of larger punctures on each elytron; intervals between punctures without row of small punctures. Epipleuron extending towards apex of elytron ( Fig. 2B ). Elytra covered with short, pale setae arranged in longitudinal rows. Setae only slightly raised and slightly overlapping each other. Elytral seta about as long as length of tarsal claw.

Abdominal ventrites less strongly but rather densely punctured compared to metasternum ( Fig. 2B ). First abdominal ventrite slightly longer than width of second ventrite. Punctures on fifth ventrite similar like on others, even and rather dense, without thickened setae and impunctate areas.

Etymology. We dedicate this species to the Augustinus Foundation, who generously contributed to the funding for purchasing the amber pieces studied. The specific epithet is to be treated as a noun in genitive case.

Remarks. New species differs from Thallisellites olgae ( Fig. 3 ) in the structure of the anterolateral angles of pronotum: Thallisellites augustinusii sp. nov. is anterior angles of pronotum with small triangular tooth not protruding significantly anteriorly ( Thallisellites olgae : anterolateral angles of pronotum strongly developed, with large acute tooth, Fig. 3A ); pronotum Thallisellites augustinusii sp. nov. is with maximal width in anterior angles ( Thallisellites olgae : maximal width of pronotum in middle, pronotum narrowed anteriorly); antennomeres four, five, and seven subquadrate ( Thallisellites olgae : antennomeres two, four, five, and seven slightly elongated); antenna short and not extending beyond basal margin of pronotum ( Thallisellites olgae : antenna long and extending beyond basal margin of pronotum). Basal short pronotal longitudinal keel not present ( Thallisellites olgae : basal short pronotal longitudinal keel present).

Figures

Figure 1. Thallisellites augustinusii Lyubarsky et Perkovsky sp. nov.: 1A – head, frontal view; 1B – antennae; 1C – general view, dorsally.

Figure 2. Thallisellites augustinusii Lyubarsky et Perkovsky sp. nov.: 2A – dorsolateral view; 2B – ventral view; 2C – lateral view.

Figure 3. Thallisellites olgae: 3A – pronotum dorsally; 3B – elytra dorsally.