Attagenus (Aethriostoma) gedanicissimus, Bukejs & HAEva & Alekseev, 2020

Bukejs, Andris, HAEva, Jiří & Alekseev, Vitalii I., 2020, A new fossil species of Attagenus Latreille (Coleoptera: Dermestidae) in Rovno and Baltic ambers, with a brief review of known fossil beetles from the Rovno amber Lagerstätte, Fossil Record 23 (1), pp. 95-104 : 96-99

Attagenus (Aethriostoma) gedanicissimus sp. nov.

urn:lsid:zoobank.org:act:4CE59EC6-79B0-43D9-B7DD-602EF4C3AA21

Figs. 1–2

Type material

Holotype: 6278 (ex. coll. Jonas Damzen JDC 8531) ( MAIG); Rovno amber; adult, sex unknown. Complete beetle is included in subtriangular, transparent amber piece, with dimensions of 25 mm × 19 mm × 16 mm and maximum thickness of 6 mm. Syninclusions consist of one specimen of Nematocera ( Diptera ) and numerous small to minute organic particles.

Paratype: “AlDlo 558” ( ADC); Baltic amber; adult, sex unknown. Complete beetle is included in transparent amber piece, with dimensions of 23 mm × 21 mm and maximum thickness of 5 mm. Syninclusion consists of one specimen of Nematocera ( Diptera ) .

Type strata

Rovno amber, upper Eocene (holotype); Baltic amber, middle Eocene (paratype) .

Etymology

The epithet of the new species is the Latin adjective gedanicus in the superlative and is formed from Gedanum, the Latin name of Gdańsk where the specimen is deposited.

Differential diagnosis

Attagenus (Aethriostoma) gedanicissimus sp. nov. differs from the single known fossil representative of the subgenus, Attagenus (Aethriostoma) turonianensis Peris et HAEva, 2016 ( USA; Late Cretaceous: Turonian; New Jersey amber) in the following characters: antennomere 11 shorter than antennomeres 9–10 combined; pronotum strongly transverse, 3× as wide as long; abdominal sutures almost straight; and larger body size; while in A. turonianensis antennomere 11 as long as antennomeres 9–10 combined; pronotum transverse, 2.1× as wide as long; abdominal sutures concave; and distinctly smaller body size (1.81 mm).

The new Eocene species A. (Aethriostoma) gedanicissimus sp. nov. differs from extant representatives of the subgenus in the unicolour blackish body and appendages (in contrast to the rufous palpi and basis of antennae in A. philippinensis HAEva, 2016 and the entirely rufous appendages in A. sparsutus ( Reitter, 1881)) and uniform, dark and comparatively sparse setation of dorsum (in contrast to the golden setation of A. philippinensis HAEva, 2016 distinctly denser on pronotal base). Dorsal setation does not form any lightcoloured patterns: fasciae or maculae (in contrast to A. undulatus ( Motschulsky, 1858) and A. irroratus ( Blackburn, 1903)) . Additionally, in new fossil species the antennomere 11 is slightly tapered beyond the midpoint.

Description of holotype

Measurements: total body length 2.8 mm; pronotal length 0.5 mm, pronotum maximum width 1.5 mm; elytral length 2.5 mm, elytral maximum width 1.7 mm.

Body widely oval, 1.6× as long as wide, convex; integument unicoloured, dark brown (as preserved); pubescence homogenous and moderately dense, consists of fine, short, recumbent, dark setae (pronotal and elytral disc and venter with finer pubescence); punctation homogenous, dense and fine.

Head hypognathous, much narrower than anterior margin of pronotum. Frons flat; frontal median ocellus apparently present. Compound eyes large, oval, prominent, entire, with distinct facets. Mouthparts free. Antennae slightly shorter than head wide (including eyes), sparsely pubescent; 11 antennomeres, clavate, with three antennomeres forming compact club and comprising about one-third of antennal length; scape large, subspherical, 1.2× as long as wide; pedicle subcylindrical, 1.5× as long as wide, smaller than scape, and distinctly wider than antennomere 3; antennomeres 3– 6 cylindrical, elongate, 1.7–2.5 × as long as wide, narrow, about 0.6× as wide as pedicle; antennomeres 7–8 nearly as wide as long, slightly dilated apically; antennomeres 9–10 strongly transverse, 1.8–2.0 × as wide as long, dilated apically; antennomere 11 ovoid, about 1.1× as long as wide, with slightly pointed apex.

Pronotum strongly transverse, about 3× as wide as long, base of pronotum nearly as wide as elytral base; lateral margins of pronotum widely rounded, posterior margin bisinuated, narrowly bordered. Hypomeron with deep antennal cavity. Prosternum not forming “collar”, covered with strong microreticulation.

Scutellar shield large, triangular with rounded apex.

Elytra about 1.3× as long as wide, widest at middle of elytral length, slightly narrowed posteriad, with anterior margin deeply concave medially, humeral callus weak. Epipleura narrow, deeply impressed, widest at humeri, reaching anterior margin of abdominal ventrite 1. Metaventrite convex, with longitudinal median line, transverse, about 2× as wide as long; posterior margin slightly concave, anterior margin bisinuated, with subtriangular process medially. Metepisternum wide, 2.6× as long as wide anteriorly.

Legs slender, moderately long; covered with microreticulation and fine, short, recumbent setae. Femora flattened, with longitudinal groove ventrally. Tibiae almost straight (protibiae slightly curved), subcylindrical, with short spine apically, tibia and femora subequal in length; protibia slightly dilated apically, slightly shorter than meso- and metatibia. Tarsi thin, moderately long, about 0.5× as long as tibia; protarsus slightly shorter than meso- and metatarsus; relative length ratios of metatarsomeres 1–5 equal to 1–1–1–1–3. Claws thin and long, free, simple.

Abdomen with five visible ventrites; abdominal sutures almost straight (sutures between ventrites 3 and 5 slightly concave); ventrite 5 with widely rounded apical margin. Relative length ratios of ventrites 1–5 (medially) equal to 10–7–6–6– 10.

Paratype

Measurements: total body length 2.8 mm; pronotal length 0.6 mm, pronotum maximum width 1.4 mm; elytral length 2.2 mm, elytral maximum width 1.9 mm.

Figures

Figure 1. Attagenus (Aethriostoma) gedanicissimus sp. nov., holotype, 6278 (MAIG): (a) habitus, dorsal view; (b) habitus, ventral view; (c) habitus, right lateral view. Scale bars = 0.5 mm.

Figure 2. Attagenus (Aethriostoma) gedanicissimus sp. nov.: (a) details of forebody, ventral view, holotype, 6278 (MAIG); (b) head and pronotum, lateral view, holotype, 6278 (MAIG); (c) habitus, dorsal view, paratype AlDlo 558 (ADC). Scale bars = 0.5mm. Abbreviations: a1–a11 are antennomeres 1–11 respectively.