Wabbel cerebricavus Alekseev 2017, sp. nov.
Creators: name: Alekseev, Vitalii I.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Wabbelidae
Wabbel
Wabbel cerebricavus

description: Wabbel cerebricavus sp. nov.
(Figs. 1-6)
Material examined. Holotype No. 1615-4 [CCHH], imago, sex unknown. Inclusion in a small yellow amber piece, embedded in a block of GTS polyester resin measuring 10 x 9 x 6 mm. Syninclusions are absent.
Type strata: Baltic Amber. Upper to midEocene.
Type locality: Baltic Sea coast, Yantarny settlement [formerly Palmnicken], Sambian (Samland) peninsula, Kaliningrad region, Russia.
Diagnosis. As stated for the new genus (vide supra).
Description. Habitus. Total body length 4.2 mm, maximal body width 1.6 mm. Elongateovate, moderately convex dorsally and subflattened ventrally, entirely black.
Head. Subquadrate; prognathous, not retracted into pronotum, finely punctate, not constricted behind eyes. Frons and vertex exceptionally deep concave, forming a hole in the basal median third of head. Clypeus dull, longitudinally triangular with angle directed basally, sharply separated, slightly convex. Gular sutures well separated, entire; gula wide, smooth. Genae projecting forwards, knobbed in front of eyes. Temples 2.5 x longer than diameter of eye, bearing a brush of long, dense, brown hair. Compound eyes small, round, entire, without interfacetal setae, not prominent, coarsely facetted (in each eye about 50 facets). Maxillary palps 4-segmented; first and third palpomeres short and transverse; second palpomere longitudinal and 3 x longer than palpomere 1 or 3; terminal palpomere cylindrical, apically rounded, being the longest. Ratio of palpomeres 1:3:1:4. Antennal insertions exposed in dorsal view; distantly in front of eyes; separated from each other by a distance narrower than the distance between eyes, but wider than the first antennomere length. Antenna with 11 freely articulating antennomeres, moniliform, nearly uniform in width, thick, not flattened, extending to elytral basis. Scape conical, pedicel and antennomeres 3 -9 slightly transverse, antennomere 10 subquadrate, antennomere 11 slightly longitudinal, truncate.All antennomeres with irregularly long (sometimes longer than length of segment), thick, black, sparce, semierect hairs.
Thorax. Pronotum transverse (in dorsal view about 0.69 times as long as its median length), slightly narrower than elytral base, finely bordered laterally and basally. Anterior margin straight, posterior margin gradually arcuate; lateral margins weakly rounded. Posterior angles rectangular, anterior angles slightly protruding forwards, rounded. Pronotal surface covered with irregular, dense and coarse punctures medially; with rasped punctures laterally. Pronotal pubescence long, accumbent, brown; directed forwards in anterior margin. Pronotum longitudinally strigose in apical and central part (nearly 20 fine keels); with two symmetrical, deep, longitudinal, tear-shaped grooves basally. Procoxa separated. Prosternal process slightly extended beyond procoxal cavities, elongate, gradually dilated apically, truncate, wider than the shortest procoxal diameter. Notosternal suture complete. Hypomeron with dense, large, and rounded punctures. Prosternum in front of coxal cavities with fine lines directed forward and accumbent long hairs. The ratio of lengths of prothorax to mesoventrite to metaventrite to abdomen is 4.5:1.0:4.5: 11.5. Metaventrite without transverse suture, distinctly shorter than the prothorax and mesoventrite combined. Metepimeron meeting anterior angle of ventrite 1. Scutellar shield strongly transverse, pentagonal with rounded angles. Elytra evenly convex; elongate oval in dorsal outline; concealing abdominal apex; separately rounded apically; with widely flattened lateral margins and apices; finely punctate; shiny. Elytral punctures small, bearing short hairs, arranged in striae, shallower on disc, becoming confused apically. Each elytron with 18 rows of fine punctures (formed by strial and interstrial punctuation equal in size), 4 rows in basal third with distinctly enlarged 8-10 punctures bearing erect hairs, 4 x as long as interval between strial punctures. All elytral intervals flat. Epipleura well developed, wide, reaching apex, without cavities. Metathoracic wings fully developed, partially exposed in the holotype specimen.
Abdomen. With five visible, similarly articulated, finely and densely punctured, finely pubescent ventrites. Relative lengths (medially) of ventrites 1 5 equal to 3.5-1.7-1.7-1.5-3.0. Intercoxal process of abdominal ventrite 1 widely triangular and acute. The first ventrite is approximately as long as the second when measured without process. Femoral lines absent.
Legs. Moderately developed. Trochantins not visible. Pro- and metacoxal cavities closed, mesocoxal cavities open. All coxae separated: procoxae separated by a distance slightly wider than the minimal procoxal diameter by the prosternal process; mesocoxae narrowly separated; meso-metaventral junction without metaventral knob; metacoxae separated by a distance approximately 2 × the coxal diameter with wide triangular process of ventrite 1. Procoxae transverse, 2 x as long as wide; mesocoxae nearly round. Metacoxae transverse, do not extend laterally to meet the elytra.
Trochanters of all legs large, completely separating femora and coxae. Femora subflattened, simple. Tibiae slightly shorter than femora; with longitudinal keels; pubescent; shortly setose apically, without crenulation, denticles, or spines. Tarsal formula 5-5-5. No tarsomeres lobed. Tarsi shorter than tibiae, pubescent below. Length of apical tarsomere subequal to combined length of tarsomeres 2- 4; tarsomeres 1-4 cylindrical, almost equal in size. Tarsal claws equal in size, thin, simple, length about one third of apical tarsomere.
Derivatio nominis. The specific epithet refers to the very peculiar concave form of frons and vertex. It is formed after the Latin “cerebrum” (brain, brainpan) and “cavus, -a, -um” (empty, hollow, concave).
The new genus exhibits a unique combination of characteristics warranting its recognition as a new family. Further investigations by X-ray micro-computed tomography (micro-CT) could help to study internal features in this specimen and may add data on the systematic placement of the taxon. If additional conspecific or congeneric specimens will be found in Baltic amber material in the future, this can be useful for understanding the position of the taxon in the system of Coleoptera, too. At the moment, it is proposed to establish the new family Wabbelidae fam. nov. based upon the monotypic genus Wabbel gen. nov. and to place this family in the system as follows:
description: Published as part of Alekseev, Vitalii I., 2017, A new coleopterous family Wabbelidae fam. nov. (Coleoptera: Cucujoidea) from Baltic amber (Cenozoic, Paleogene, Eocene), pp. 29-41 in Baltic Journal of Coleopterology 17 (1) on pages 29-41, DOI: 10.5281/zenodo.10905254