Paha vanivanitatum Alekseev et Bukejs, 2024

ALEKSEEV, VITALII, MCKELLAR, RYAN C. & BUKEJS, ANDRIS, 2024, A revision and addition to Zopheridae (Coleoptera: Tenebrionoidea) in Baltic amber: possible connections between modern Holarctic distributions and Eocene ‘ amber forests’, Zootaxa 5536 (2), pp. 201-247 : 210-213

Paha vanivanitatum Alekseev et Bukejs sp. nov.

( Figs 7–10 )

Type material. Holotype:No. ABAC 064 [ ACAB] (No. 3207 ex. coll. Marius Veta); “Holotype / Paha vanivanitatum sp. nov. / Alekseev et Bukejs des. 2024” [red printed label]; adult, sex unknown. A complete beetle with exposed distal part of metathoracic wing included in a transparent, yellow amber piece with 18× 12 mm and a maximum thickness of 1 mm, preserved without supplementary fixation. Ventral side of head and anterior portion of prosternum completely obscured by milky cover. Syninclusions: few stellate Fagaceae trichomes.

Type stratum. Baltic amber from Eocene amber-bearing Blaue Erde deposits; estimated age: middle–late Eocene (Standke 1998).

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

Description. Measurements: total body length (including visible part of head) 2.4 mm, maximum body width (across elytra) 0.9 mm; pronotal length 0.6 mm, maximum pronotal width 0.8 mm, basal pronotal width 0.7 mm; elytral length (along elytral suture, including scutellum) 1.5 mm; antennal length 0.38 mm.

Body subparallel-sided, elongate, about 2.7× as long as wide, weakly convex dorsally and ventrally, unicolorous black (as preserved). Pubescence: head, pronotum and elytra sparsely covered with short, inconspicuous, curved, semierect setae that are shorter than diameter of puncture or tubercle from which they arise.

Head prognathous, transverse; densely granulose dorsally, each round granule bearing short seta. Anterior margin of clypeus rounded. Compound eyes small, slightly convex, apparently hemispherical, without interfacetal setation. Antennal insertions concealed dorsally; antennal grooves ventrad eye apparently absent. Antennae short, extending slightly beyond anterior one-third of pronotal length; 10-segmented with distinct 1-segmented antennal club, antennal club with fine suture between completely fused antennomeres 10 and 11, and sparsely setose; scape almost invisible from above, wide, subcylindrical; pedicel cylindrical, slightly transverse, about as wide as scape; antennomere 3 conical, elongate, about 1.5× as long as wide, about 1.3× longer than antennomere 4; antennomeres 4–8 subtrapezoidal, slightly dilated apically, as long as wide; antennomere 9 trapezoidal, dilated apically, transverse, 1.3× as wide as long; antennomere 10 widest, widely oval, with widely rounded apex, nearly as long as wide, 2.1× wider than antennomere 9.

Pronotum slightly transverse, 1.3× as wide as long, widest near midlength, weakly narrowed anteriad and posteriad, with maximum pronotal width / basal pronotal width = 1.1; pronotal surface covered with rounded granules. Pronotal disc with elevated central area delimited by two parallel, longitudinal, slightly curved carinae; elevated area almost flat, with longitudinal shallow impression along midline, and about 0.6× as wide as pronotal maximum width. Anterior pronotal margin sinuate in dorsal view; posterior margin almost straight medially, shallowly concave laterally; lateral margins subparallel, slightly rounded, serrate.Anterior angles slightly prominent, rounded; posterior angles almost rectangular. Prothoracic notosternal suture apparently complete. Prohypomera densely granulate. Prosternum convex, with dense and coarse punctation. Intercoxal prosternal process elongate, extending beyond posterior margin of procoxae, with rounded apical margin, slightly dilated in anterior one-third of length, with lateral margins emarginate, and rather wide, about 1.3× as wide as diameter of procoxa. Procoxal cavities open posteriorly.

Scutellar shield minute, cordiform.

Elytra almost parallel-sided in anterior three-quarters of length and tapered at apex, about 1.8× as long as wide combined, as wide as pronotum basally, convex, carinate, 2.7× longer than pronotum. Humeral angles rounded, weakly serrate. Elytra striate-punctate. Scutellary striole absent. Elytral striae with rows of elongate granules; odd elytral intervals (1, 3, 5, 7) carinate. Epipleura well-developed, widest in basal half, slightly narrowing posteriad, reaching elytral apices, densely covered with round granules. Meso- and metaventrites densely and coarsely punctate. Mesocoxal cavities closed. Metaventrite with disc almost flat, slightly longer than abdominal ventrite 1; discrimen distinct in posterior half. Relative length ratio of pro- to meso- to metaventrite to abdomen approximately equal to 10:6:9:27. Metathoracic wings present.

Legs rather short and robust, finely punctate and sparsely setose. Procoxa small, nearly rounded, and widely separated by about 1.3× diameter of procoxa; mesocoxae subcircular, separated by 0.7× diameter of mesocoxa; metacoxae widely oval, transverse, narrowly separated by about 0.5× longitudinal diameter of metacoxa. Femora nearly spindle-shaped, slightly flattened, widened medially; femora slightly longer than tibiae. Tibiae slightly curved, with short, fine setae apically; protibiae without apical spurs. Tarsal formula 4-4-4; tarsomeres not dilated, with sparse, fine setation ventrally; tarsomere 4 longest, longer than tarsomeres 1–3 combined, slightly curved. Claws simple, large, about 0.5× as long as tarsomere 4, robust.

Abdomen with five visible ventrites, abdominal sutures distinct throughout length; densely covered with large punctation, distance between punctures distinctly smaller than diameter of one puncture. Relative length ratios of ventrites 1–5 equal to 11:7:5:4:5. Abdominal ventrite 1 with small, narrow, triangular intercoxal process with rounded apex. Abdominal ventrite 5 with widely rounded apical margin.

Differential diagnosis. Paha vanivanitatum sp. nov. differs from extant congeners in the combination of the following characters: larger body size (1.8–2.1 mm in P. guadalupensis ), pronotum slightly transverse, 1.3× as wide as long and widest at midlength (pronotum strongly transverse, twice as wide as long in P. guadalupensis and widest near apical one-quarter of length in P. laticollis ), and anterior pronotal angles less prominent.

The new species can be easily distinguished from other extinct Colydiinae preserved in Baltic amber based on the combination of generic characters, most obviously in the presence of 10-segmented antennae with 1-segmented club, short and inconspicuous setation of pronotum and elytra, pronotal disc with elevated central area and two longitudinal carinae, and elytral intervals carinate.

Derivatio nominis. The specific epithet vanivanitatum is derived from the Latin phrase “ Vanitas vanitatum et omnia vanitas ” (meaning “vanity of vanities, and all is vanity”), referring (1) to the emptiness of inclusions in amber, (2) to the allegorical genre of painting (Vanitas) which uses symbolism to show the transience of human life and the certainty of death, and (3) to the lack of immediate practical use from amber insects studies. The name is used as noun in apposition.

Distribution of congeners. The genus Paha occurs in Nearctic and Neotropical regions and is represented by four extant species ( Sharp 1894; Dajoz 1984; Ivie et al. 2016): P. guadalupensis Dajoz, 1984 , P. laticollis (LeConte, 1863) , P. mexicana (Hinton, 1935) , and P. mimetes ( Sharp, 1894) . The extinct species described in the current paper indicates both the Eocene age of the genus and the presence of representatives of this genus in forest paleoecosystems of the Western Palearctic during the Eocene.

Ecology of congeners. The natural history of the genus is poorly understood. The single Nearctic species, P. laticollis is associated with oaken logs and old oaks ( Quercus ) and is also reported under bark of the fabacean tree Lysiloma bahamensis ( Blatchley 1930; Stephan 1989). The ecology of three other species from Central America (described from Belize, Guadeloupe, and Mexico) is unknown. Paha vanivanitatum sp. nov. could possibly be a member of an Eocene forest community associated with fagacean wood.

Figures

FIGURES 7–8. Paha vanivanitatum sp. nov., holotype, No. ACAB 064 [ACAB]: 7—habitus, dorsal view; 8—habitus, ventral view. Scale bar = 0.5 mm.

FIGURES 9–10. Paha vanivanitatum sp. nov., holotype, No. ACAB 064 [ACAB]: 9—details of forebody, dorsal view; 10— prothorax, ventral view. Abbreviations: a2–a10—antennomeres 2–10 respectively; lc—longitudinal carina; pc—procoxa; pf— profemur; pp—prosternal process; pt—protibia. Scale bars = 0.2 mm.