Crepidodera tertiotertiaria, Bukejs, Andris, Biondi, Maurizio & Alekseev, Vitalii I., 2016

Bukejs, Andris, Biondi, Maurizio & Alekseev, Vitalii I., 2016, New records and species of Crepidodera Chevrolat (Coleoptera: Chrysomelidae) in Eocene European amber, with a brief review of described fossil beetles from Bitterfeld amber, Zootaxa 4193 (2), pp. 390-400 : 391-396

Crepidodera tertiotertiaria sp. nov.

( Figs 1–9 )

Type material. Holotype: “1045 C” [GPIH]; sex unknown. Complete beetle with partly exposed hind wings is included in relatively small, suboval amber piece (length 35 mm, width 29 mm, and maximum thickness 7 mm), yellowish in color, without supplementary fixation. Mouthparts and ventral side of the specimen obscured by “milky” opacity. Other animals and plant syninclusions are absent in examined amber piece.

Paratype: “AB 044” [CAB]; sex unknown. Complete beetle is included in small, roundish amber piece (diameter 18 mm, maximum thickness 6 mm, weight 1.3 grams). Ventral side of specimen and legs almost not visible because of structure of amber. There are also some small stellate Fagaceae trichomes, and few small gas vesicles in examined amber piece; animal syninclusions are absent.

Paratype: “4436 C” [ GPIH]; sex unknown. Complete beetle is included in small, subsquare amber piece (length 21 mm, width 18 mm, and maximum thickness 5 mm), yellowish in color, without supplementary fixation. Mouthparts and ventral part of head obscured by “milky” opacity. There are also four specimens of Diptera, one partly damaged specimen of Araneae , some segments (legs) of insects, numerous stellate Fagaceae trichomes, many gas vesicles, and small pieces of organic material in examined amber piece.

Paratype: “2340 C” [ GPIH]; sex unknown. Complete beetle is included in small, elongate oval amber piece (length 20 mm, width 9 mm, and maximum thickness 4 mm), yellowish in color, without supplementary fixation. Mouthparts, meso- and metathorax covered by gas vesicles. There are also few small stellate Fagaceae trichomes in examined amber piece; animal syninclusions are absent.

Paratype: “337-1” [CCHH]; sex unknown. Complete beetle with partly exposed hind wings is included in relatively small, suboval amber piece (length 30 mm, width 18 mm, and maximum thickness 9 mm), yellowish in color, without supplementary fixation. Other animal and plant syninclusions are absent in examined amber piece.

Paratype: “002” [BAQ]; sex unknown. Complete beetle is included in small, subelliptical amber piece (length 12 mm, width 9.4 mm, and maximum thickness 4 mm), yellowish in color, without supplementary fixation. Mouthparts and prothorax obscured by “milky” opacity on left side. Other animal and plant syninclusions are absent in examined amber piece, except few small gas vesicles.

Additional non-type specimens. “1450 C” [ GPIH]; sex unknown. Complete beetle is included in small, subtriangular amber piece (length 20 mm, width 21 mm, and maximum thickness 8 mm), yellowish in color, without supplementary fixation. Specimen is visible only in lateral view; characters of head and legs are not visible. Syninclusions: one specimen of Tenebrionidea ( Coleoptera ), one poorly visible specimen of Cucujidae (Coleoptera) , two ant specimens ( Hymenoptera : Formicidae ), nine specimens of Nematocera (Diptera), few stellate Fagaceae trichomes, and small pieces of organic material.

“337-2” [ CCHH]; female. Complete beetle with partially exposed styli is included in small, transparent yellow amber piece embedded in block of GTS-polyester resin with dimensions 12 x 9 x 4 mm. Dorsal and ventral surfaces of specimen are poorly visible; mouthparts and ventral part of head obscured by “milky” opacity. Other animal and plant syninclusions are absent (except few small gas vesicles).

“874 C” [ GPIH], sex unknown. Complete beetle is included in small, subtriangular amber piece (length 25 mm, width 13 mm, and maximum thickness 8 mm), yellowish in color, without supplementary fixation. Head and ventral part of specimen obscured by “milky” opacity. Syninclusions: one ant specimen ( Hymenoptera : Formicidae ), and few small pieces of organic material.

Type strata. Baltic Amber , mid-Eocene to Upper Eocene.

Type locality. Yantarny village (formerly Palmnicken), the Kaliningrad Region, Russia.

Etymology. The specific name is derived from the combined Latin words tertius (third) and tertiarius (of the Tertiary), referring to the ordinal number of the fossil species in the genus (the third described) and the time of species origin (the first period of the Cenozoic era, which was once referred to as the Tertiary).

Differential diagnosis. Prior to this study, two fossil species of Crepidodera were known. Crepidodera tertiotertiaria sp. nov. differs from C. decolorata Nadein & Perkovsky in having finer pronotal punctation, narrower antennal calli, impunctate frons and vertex, and black legs and antennae. New species differs from C. svetlanae Bukejs in narrower antennal calli, and in having more conspicuous pronotal punctation, and smaller body size.

Crepidodera tertiotertiaria sp. nov. shows many similarities with some extant Eastern-Nearctic species, especially with C. spenceri ( Lazorko, 1974) . However, new species differs from extant species in having finer and moderately denser pronotal punctation, entirely black legs and antennae, weakly but distinctly convex elytral interstriae, and distinctly bordered elytral lateral margins.

Description. Holotype. Body length 2.2 mm, maximum width 1.3 mm; widely oval, moderately convex dorsally; unicolorous black, shiny; glabrous dorsally.

Head hypognathous, relatively small, narrower than anterior margin of pronotum, shiny; frons and vertex slightly convex, impunctate (frons with few fine punctures near each eye), with fine transverse rugosity. Labrum transverse, slightly convex, with anterior margin almost straight, and with rounded anterior angles; surface covered with transverse rugosity; with six setiferous pores. Clypeus elevated at anterior margin. Genae short, with small and dense punctures. Compound eyes positioned laterally, entire, convex, with distinct facets; eyes relatively large, with vertical diameter about 1.4 times transverse diameter; distance between eyes nearly equal to 1.8 transverse diameter of one eye. Frontal ridge narrow, sharp; forming inverted T-shaped ridge with clypeus. Antennal calli smooth and shiny, contiguous, weakly convex; narrow, distinctly narrower than diameter of antennal socket; welldelineated from vertex and frontal ridge. Supracallinal sulcus deep, curved. Ocular sulci deep, almost straight, reaching frontal calli. Supraocular setiferous pore present. Distance between antennal sockets nearly equal to diameter of one socket. Antenna 11-segmented, filiform; moderately long, extends nearly to middle of elytra. Scape subcylindrical, about 1.4 times as long as wide, slightly longer and thicker than antennomere 2; pedicel thick, subcylindrical, about 0.77 times length of scape; antennomeres 3–6 subequal in shape and wide, slightly dilated distally, antennomere 3 about 0.6 times as wide as antennomere 2, and about as long; antennomeres 7–11 wider than antennomere 6, distinctly dilated distally, apex of last antennomere pointed. Relative length ratios of antennomeres 1–11: 14-11-11-9 - 13-10-14-15 -15-15-20.

Pronotum transverse, about 1.4 times as wide as long, widest in posterior one-third, and moderately convex; lateral margins weakly rounded, anterior margin arcuate, almost straight in dorsal view; posterior margin sinuate; lateral and posterior margins with distinct, narrow bordering, and anterior margin with less conspicuous, narrow bordering. Anterolateral callosities relatively large, protruding; anterior angles rectangular and posterior angles obtuse, with each angle bearing setiferous pore. Base of pronotum distinctly narrower than elytral base. Pronotal punctation fine (distinctly smaller than elytral punctures), and moderately dense, with distance between punctures larger than diameter of a puncture; punctation at sides more conspicuous. Antebasal transverse sulcus deep, slightly curved in middle; longitudinal basal impressions short, deep and curved, with their length distinctly shorter than distance between impression and posterolateral callosity.

Scutellum small, triangular with rounded apex; transverse, about 1.8 times as wide as long. Elytra about 1.2 times as long as wide, moderately convex, widely oval, tapered apically, lateral sides slightly rounded and distinctly bordered, base concave; humeral calli well-developed, distinctly protruding. Elytral punctures small (nearly as large as diameter of eye facet) and dense, arranged in regular striae, distance between striae about 2–4 times diameter of puncture, striae less distinct at apices, distance between punctures in striae equal to 0.5–1.5 times diameter of puncture; interstriae weakly but distinctly convex, covered with very fine secondary punctation forming rows. Sutural stria present. Elytral apices separately rounded. Apical angles of elytra without teeth. Epipleura subhorizontal (clearly visible in lateral view), wide anteriorly, gradually narrowing posteriorly, reaching elytral apex, at inner margin with row of fine punctures. Hind wings apparently well developed.

Legs thin and relatively long; covered with short, pale, recumbent setae. Metafemora robust, swollen. Metatibiae thin, slightly flattened and expanded apically. Metatarsi originate from apices of metatibiae. Metatarsomere 1 short, about as long as metatarsomeres 2–3 combined; metatarsomere 3 deeply bilobed. Protarsomeres weakly dilated; protarsomere 1 about as wide as apex of protibia. Tarsal claws relatively small, appendiculate, with large denticle.

Paratypes. “AB 044”: body length 2.0 mm, maximum width 1.1 mm. Pronotal punctation less conspicuous than in holotype. Anterior angles of pronotum with long seta, about 0.7 times as long as lateral margin of pronotum; posterior angles with short seta (not longer than one-quarter length of lateral margin of pronotum). Elytral striae more regular at apices than in holotype. Mesotarsomere 1 distinctly dilated, about as wide as apex of mesotibia, distinctly wider than mesotarsomere 2. “4436 C”: body length 2.0 mm. Proventrite with small, dense punctures; prohypomera smooth, shiny; prosternal process moderately wide. Metaventrite convex, shiny, without distinct punctures (only at anterior margin, with transverse row of small punctures); metepisternum with fine and dense punctures. Pro- and mesocoxae subglobose; metacoxae transverse, elongated oval. Procoxal cavities apparently closed posteriorly. Abdomen shiny, with fine, sparse punctures and short, sparse semi-erect setae. Relative length ratios of ventrites 1–5 equal to 12-3-3-3-8. “2340 C”: body length ca. 2.0 mm. Pronotal punctation more conspicuous than in holotype. “337-1”: body length 2.0 mm. Elytra with weak blue metallic lustre. ”002”: body length 2.2 mm, maximum width 1.3 mm.

Additional non-type specimens. “1450 C”: body length 2.0 mm. “337-2”: body length 2.2 mm, maximum width 1.3 mm. Protarsomeres weakly dilated; protarsomere 1 about as wide as apex of protibia. Styli visible ( Fig. 9 ). “874 C”: body length ca. 2.2 mm.

Figures

FIGURES 1 – 3. Crepidodera tertiotertiaria sp. nov., holotype: 1 — habitus, dorsal view; 2 — habitus, ventral view; 3 — head, frontal view.

FIGURES 4 – 6. Crepidodera tertiotertiaria sp. nov.: 4 — details of anterior part of body, paratype “ AB 044 ” [CAB]; 5 — habitus, lateral view, paratype “ 4436 C ” [GPIH]; 6 — claws of metatarsus, non-type specimen “ 337 - 2 ” [CCHH].

FIGURES 7 – 9. Crepidodera tertiotertiaria sp. nov.: 7 — details of elytra and pronotum, lateral view, paratype “ 4436 C ” [GPIH]; 8 — habitus, ventral view, non-type specimen “ 337 - 2 ” [CCHH]; 9 — exposed styli, dorsal view, non-type specimen “ 337 - 2 ” [CCHH].