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

description: Family Wabbelidae fam. nov.
Type genus. Wabbel gen. nov.
Composition. The new family is proposed for one generic group only, consisting of the one new species Wabbel cerebricavus sp. nov. from Baltic amber.
Description. The new family includes one genus and one species as described above in detail. The list of the most important (Leschen et al. 2005) characteristics can be summarized as follows: Body form oblong, head prognathous, metacoxae not meeting edges of elytral epipleura, metepimeron meeting anterior angle of ventrite 1, metaventrite shorter than prothorax and mesoventrite combined, tarsi not lobed, tarsal formula 5-5-5, metaventrite without transverse suture, basal ventrite free, antennal insertions not concealed, protibiae simple (without crenulation, denticles, or spines), procoxal cavities closed, mesocoxal cavities open, metacoxal cavities closed, procoxae strongly transverse, head without subocular antennal grooves, elytra not truncate and concealing abdominal apex, ventrite 1 without femoral lines, pronotum without sublateral carinae, elytra without ridges, antennae 11-segmented with antennal club indistinct, epipleuron without deep cavity, procoxal cavities without narrow lateral slits, prosternal process wider than the shortest diameter of a procoxal cavity, head without postocular constriction, genae projecting forward, elytral punctuation seriate, mesocoxal cavities narrowly separated.
Diagnosis. First ventrite undivided by metacoxae and prothorax without notopleural sutures. These findings suggest placement of Wabbelidae fam. nov. in the suborder of Polyphaga, excluding a relationship of the new taxon to Rhysodidae (fairly similarly thick moniliform antennae, 5-segmented tarsi, small eyes, dorsal surface of head with grooves and lobes). Not strongly projecting procoxae exclude a possible membership of Staphylinoidea with similarly formed tarsi and antennae. The appendages’ morphology (antennae, legs) and some other habitual characteristics (e.g. elytral punctuation) do resemble those of the families Jacobsoniidae Heller, 1926 and Ptinidae Latreille, 1802 from the series Bostrichiformia.
Jacobsoniidae can be recognized by a minute, narrowly elongate body, an elongate prothorax, lack of a visible scutellum, and a markedly elongate metaventrite (at least 2.5 x as long as mesoventrite), combined with a relatively short abdomen and extremely slender metanepisterna, which are potential synapomorphies of the family (Löbl & Burckhardt 1988; Lawrence& Leschen 2010; Bi et al. 2015; Cai et al. 2016). Additionally, all known modern Jacobsoniidae have antennal insertions concealed from above and a pronotal disc without paired basal impressions (Lawrence & Leschen 2010). The characteristics of Wabbel gen. nov. representing Wabbelidae fam. nov., i.e. comparatively short metaventrite, distinct transverse scutellum, metepisterna not slender, abdomen not shortened, paired pronotal impressions, and dorsally exposed antennal insertions, exclude the beetle from the systematical vicinity of apparently similar Jacobsoniidae.
In addition, Wabbel gen. nov. is similar to some members of the subfamily Ptininae by the widely separated metacoxae without coxal plates, by the open mesocoxae, by the hidden trochantins, by the long femora, by the non-clubbed antennae, by the legs with pentamerous tarsi and the terminal tarsomere being the longest, by the separation of procoxae by prosternal process (present in numerous genera of spider-beetles), and by the triangular clypeal form. The reasons to exclude the Ptinidae from possible groups to which the new taxon can be assigned are the following: Wabbel gen. nov. has a large head with long temples and gula, whereas Ptininae have a head moderately deflexed downwards and constricted in pronotum (Mynhardt & Philips 2013); in Ptininae the antennal insertions are closely together between eyes (Belles 1978; Philips 2000), whereas the antennal insertions in Wabbel gen. nov. are moderately wide, separated from each other and from eyes; Wabbel gen. nov. has prothoracic lateral margins, whereas in ptinids such structure is absent (Mynhardt & Philips 2013); in Ptininae the first 3 ventrites are connate while ventrite 4 is often reduced (Philips 2000), whereas the new taxon has basal ventrites with complete sutures and nearly equal in length; in contrast to the newly described taxon, ptinids have open procoxal cavities (Philips 2000).
To the author’s opinion, the attempt to assign the new genus to Jacobsoniidae or Ptininae (Ptinidae) would destroy the modern concepts of these taxa. The new genus has a highly specialized head, whwereas specialization in ptinids (and, possibly, in the whole bostrichoid lineage) is connected with different pronotal modifications. The trend towards integration of the head and prothorax in a single unit in Ptininae and the apparent absence of such integration in Wabbel gen. nov. are an important obstacle to evolutionary relation. The antennal form in Ptininae and Jacobsoniidae distinctly varies between the genera (moniliform in Sarothrias, distinctly clubbed in Derolathrus and Saphophagus) and species of one genus (e.g., Polyplocotes Westwood 1869 has antennae with compressed, widened, or reduced segments in different species). A similar antennal form may be observed in several unrelated coleopteran myrmecophiles while the number and form of antennal segments may vary within one genus (Lawrence & Reichardt 1969; Bell & Philips 2009). Thus, such characters are not of paramount importance. The more important dissimilarities between Wabbelidae fam. nov., Ptinidae, and Jacobsoniidae are listed above.
The not concealed head without a median ocellus, not excavated metacoxae without vertical posterior face, absent metacoxal plates, not approximated antennal insertion, not truncate elytra, tarsal formula 5-5-5, simple claws, well-developed intercoxal process of first abdominal ventrite, and long antennae allow for tentatively placing Wabbel gen. nov. among Cucujoidea.
This superfamily includes 25 recent families and remains difficult to characterize owing to the phenotypic heterogeneity exhibited in this group. There are no characteristics that unite all the families of Cucujoidea as the superfamily is characterized by the following combination of features only (Robertson et al. 2015): Adults with procoxal cavities internally open (mostly), tarsal formula 5-5- 5 in female and 5-5-5 or 5- 5- 4 in male animals (rarely 4-4-4). However, it has not been possible to definitely assign the taxon to any known family of the superfamily.
The new family Wabbelidae fam. nov. is compared with all families of the superfamily in consecutive order as the new taxon obviously differs from:
Passandridae by the open mesocoxal cavities and by the not parallel-sided body form;
Helotidae by the metaventrite without transverse complete suture and by the transverse procoxae;
Nitidulidae, Kateretidae, and Monotomidae by the absence of an antennal club and by not exposing the pygidium;
Laemophloeidae by the pronotum without sublateral carinae and by elytra without longitudinal ridges;
Protocucujidae by the simple non-lobed tarsomeres;
Smicripidae by the 5-segmented tarsi; Silvanidae by the absence of lobed tarsomeres and by the transverse fore coxae;
Sphindidae by the absence of an antennal club and by a tubercle or cavity on the mandible; Cyclaxyridae by the elongate, not strongly convex body and by the absence of a deep cavity on the epipleuron;
Hobartiidae by the non-clubbed antennae; Tasmosalpingidae, Lamingtoniidae, and Phloeostichidae by the closed procoxal cavities; Cucujidae by the markedly convex dorsal surface;
Cavognathidae by the absence of narrow lateral slits on the procoxal cavities, the frons without deep pits, and the closed procoxal cavities; Myraboliidae by the absence of slits on the procoxal cavities, the body form not flattened and parallel-sided, and the non-3-segmented club;
Agapythidae by the prosternal process wider than the shortest diameter of a procoxal cavity and by the head without a postocular constriction;
Priasilphidae by the narrowly separated mesocoxal cavities, the abdomen with free ventrites, and the seriate punctuation of the elytra;
Cryptophagidae by the open mesocoxal cavities, the transverse procoxae, the moniliform antennae, and the seriate elytral punctuation; Phalacridae by the elongate, not strongly convex body, the moniliform antennae, and the simple (non-toothed) claws;
Erotylidae by the non-clubbed antennae;
Boganiidae by the mandibles without setose cavities on the dorsal side and by the all-simple tarsomeres (non-lobed ventrally);
Cybocephalidae by the not rounded body, the non-lobed tarsomeres, and the 5-segmented tarsi.
According to Bouchard et al. (2011), the superfamily Cucujoidea Latreille, 1802 includes two families that are also extinct: Parandrexidae Kirejtshuk, 1994 and Sinisilvanidae Hong, 2002. The position of Sinisilvanidae within Silvanidae is considered unclear (according to its original description probably within the subfamily Silvaninae sensu stricto) by Kirejtshuk (2011). The Mesozoic family Parandrexidae (as diagnosed by Soriano et al. 2006) differs from newly described Wabbelidae fam. nov. by the subfiliform antennae (moniliform in Wabbelidae), the long mandibles, the long palpomeres, the narrowly separated and flat coxae, and the 4-segmented tarsi.
Wabbelidae fam. nov. can readily be distinguished from other Cucujoidea by the following unique combination of characteristics: (1) thick moniliform antennae without distinct 3-segmented club, (2) modified (deeply concave) frons and vertex, (3) longitudinally strigose pronotum with pair of basal grooves, (4) wide gula with complete and well-separated gular sutures, (5) pentamerous non-lobed tarsi with first tarsomere equal to the second, (6) seriate punctuation of elytra, and (7) dorsally non-flattened body.
Taken separately, these characteristics are not unique and occur in several taxa of modern beetles. However, the complex of the characteristics listed above is unique for the superfamily. It allows assuming that Wabbel gen. nov. is a representative of a formerly unknown taxon, whose rank is equal to other families of Cucujoidea.
In the most recent key to cucujoid families (Leschen et al. 2005), Wabbel cerebricavus (and correspondingly Wabbelidae fam. nov.) runs to couplet 31, Priasilphidae / Agapythidae, having occiput without stridulatory files. Insertion of a couplet “31a” at this point would separate Wabbelidae:
31a. Antennae moniliform, frons and vertex deeply concave …...………………...................…… Wabbelidae -Antennae clubbed, head without deep grooves or concavity.........……………..…………… 31
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