The family Trogossitidae, the bark-gnawing beetles, constitute one of the lesser families of the superfamily Cleroidea, with about 600 recent species described to date (Kolibáč Reference Kolibáč2013). The modern classification of the Trogossitidae was developed from the classic work of Reitter (Reference Reitter1876), later studied by Crowson (Reference Crowson1964, Reference Crowson1966, Reference Crowson1970), Barron (Reference Barron1971) and Ślipiński (Reference Ślipiński1992) and, most recently, by Kolibáč (Reference Kolibáč2005, Reference Kolibáč2006, Reference Kolibáč2008) and Kolibáč & Leschen (Reference Kolibáč, Leschen, Leschen, Beutel and Lawrence2010).
The tribe Gymnochilini Lacordaire comprises a highly adapted group consisting of eight genera (Leschen & Lackner Reference Leschen and Lackner2013). They are rapid flyers, living on fallen logs and hunting for bostrichids, scolytids and other insects (with the exception of a number of apterous species of Phanodesta Reitter from Juan Fernandez Island). Most of the species have relatively large eyes, pronotum transverse with extended anterior corners and dorsal body surface often covered with scales or tufts of thick setae. Some of them (Anacypta Illiger, Xenoglena Reitter) strongly resemble the jewel beetles (Buprestidae) in their body shape and swift movement, whilst other species are capable of jumping.
Seidlitzella Jakobson was a monotypic genus in which the single extant species, S. procera (Kraatz, Reference Kraatz1858), is distributed in Greece, Turkey and Cyprus (Kolibáč Reference Kolibáč, Löbl and Smetana2007). The species is predatory. Adults are found on logs of various trees (e.g., the Cilician fir Abies cilicica (Antoine & Kotschy) Carrière, Reference Carrière1855), and larvae have been found under pine bark (Schawaller Reference Schawaller1993). It was once considered related to the Palaearctic species of Leperina Erichson, as suggested by Schawaller (Reference Schawaller1993). However, his formal synonymisation of Seidlitzella was not confirmed in a recent study by Leschen & Lackner (Reference Leschen and Lackner2013), who established the new genus Kolibacia for Leperina tibialis Reitter, Reference Reitter1889 and L. squamulata (Gebler, Reference Gebler1830).
The list of fossil members of Trogossitidae included about 26 species from the Cenozoic and Mesozoic (Ponomarenko & Kireitshuk Reference Ponomarenko and Kireitshuk2009–2015; Schmied et al. Reference Schmied, Wappler and Kolibáč2009; Kolibáč Reference Kolibáč2013). In addition, several new fossil trogossitids have been recently described from the Neogene of Germany (Kolibáč et al. Reference Kolibáč, Adroit, Gröning, Brauckmann and Wappler2016) and the Jurassic and Cretaceous of Spain and China (Yu et al. Reference Yu, Leschen, Slipinski, Ren and Pang2012, Reference Yu, Slipinski, Leschen, Ren and Pang2014, Reference Yu, Slipinski, Leschen, Ren and Pang2015; Peris et al. Reference Peris, Kolibáč and Delclòs2014). Interestingly, only two trogossitid species have been described from Baltic amber so far, both classified within the Lophocaterinae (Kolibáč et al. Reference Peris, Kolibáč and Delclòs2010; Kolibáč Reference Kolibáč2011). A brief updated review of described trogossitid fossils can be found in Table 1.
Table 1 An updated review of described fossil species in the family Trogossitidae
The single fossil species of Gymnochilini previously known is Gymnocheilis obesa (Heer, Reference Heer1862) (described as Gymnochila Erichson) from the middle Miocene of Germany (Baden-Württemberg: Öhningen). The second fossil species of Gymnochilini (which is also the second known species of Seidlitzella) is described below.
1. Material and methods
The holotype is preserved in a polished piece of transparent, orange-tinted amber with a reddish halo around the inclusion. The amber piece is embedded in polyester resin (dimensions 17×13×8 mm). The specimen is damaged; the left elytron and the left wing are broken and partly absent. The ventral side and head are not clearly visible as they are surrounded by a cloudy coating. Syninclusions consist of four stellate hairs (trichomes), probably from a beech flower (Fagaceae). The paratype is preserved in a polished piece of transparent, yellow-orange amber embedded in polyester resin (dimensions 16×13×6 mm). The beetle specimen is complete; syninclusions consist of stellate hairs and one specimen of Acari (Oribatida), which is separately deposited under collection number CCHH 1753-2b.
The specimens examined were originally loaned from the private collection of Christel and Hans Werner Hoffeins (CCHH, Hamburg, Germany). Both amber pieces have been deposited at the Senckenberg Deutsches Entomologisches Institut in Müncheberg, Germany (SDEI), as part of the institutional amber collection for permanent preservation.
Photographs of the holotype and recent specimens were taken with a Leica Z16Apo. The body parts of the holotype were measured with LAS 3.6.0 software, which was also used to stack certain images. The body parts of the paratype were measured by means of an ocular grid.
2. Systematic palaeontology
Family Trogossitidae Latreille, Reference Latreille1802 Subfamily Trogossitinae Latreille, Reference Latreille1802 Tribe Gymnochilini Lacordaire, Reference Lacordaire1854 Genus Seidlitzella Jakobson, Reference Jakobson1915
Type species. Peltis procera Kraatz, Reference Kraatz1858.
Diagnosis. Dorsal surface without pubescence and without distinct vestiture composed of scales or thick setae (elytral punctures filled with dust and bearing only minute setae or scales or vestiture absent); head pro- or orthognathous, with antennal grooves and single pair of laterally-situated eyes; ventral part of cranium with long setae at sides; antennal club loose, three-segmented; antennomeres 9–11 with sensorial fields; pronotum distinctly transverse (width/length ratio c.1.6–1.7), with anterior angles projecting and acuminate; procoxal cavities externally closed; elytron with ten non-beaded carinae, window punctures absent; protibia with large, hooked spur at apex, with four small spines along outer edge; first tarsomere shortened but present, tarsal formula seemingly 4–4–4; last tarsomere as long as other tarsomeres together; tarsal claw large, without denticle; abdomen with five ventrites.
Remarks. Body unicolorous, compact, lacking distinct vestiture and window punctures (rectangular punctures connected with each other; Leschen & Lackner Reference Leschen and Lackner2013), and a double row of relatively small, rounded intercarinal punctures distinguish Seidlitzella from the eastern Palaearctic genus Kolibacia and the “Gondwanan” Leperina and Phanodesta (Fig. 1A–E). These characters may also be found in the fossils described herein. Species of Kolibacia are slimmer, with a distinct vestiture composed of scales or thick setae, and window punctures occurring in the intercarinal spaces of elytra. The absence of large spines along the outer edges in all pairs of tibiae differentiates Seidlitzella from species of the genus Melambia Erichson, of similar habit (Fig. 1F), in which the elytral vestiture is completely absent and the species are more elongate. The pronotum in Kolibacia and Melambia is weakly transverse (width/length ratio about 1.1–1.2) whilst the ratio is higher than 1.5 in Seidlitzella. Keys to the relevant genera and their detailed diagnoses are included in Kolibáč (Reference Kolibáč2013), Leschen & Lackner (Reference Leschen and Lackner2013), Yoshitomi (Reference Yoshitomi2014) and Yoshitomi & Lee (Reference Yoshitomi and Lee2014). Some outer diagnostic characters of the relevant genera are listed in Table 2.
Figure 1 Elytral sculpture and vestiture of extant Gymnochilini: (A) Melambia gigas (Fabricius); (B) Seidlitzella procera (Kraatz); (C) Kolibacia squamulata (Gebler); (D) Leperina cirrosa Pascoe; (E) Phanodesta cribraria (Blanchard). (F) Melambia gigas (Fabricius), apical portion of protibia. Scale bars = 0.5 mm.
Table 2 Comparison of some outer characters in extant genera of Gymnochilini, apart from the “split-eyed group”
Seidlitzella hoffeinsorum sp. nov. (Figs 2–5)
Figure 2 (A–E) Seidlitzella hoffeinsorum sp. nov., holotype: (A) dorsal view; (B) ventral view; (C) detail of elytral sculpture; (D) apical part of elytron; (E) head, ventral view. (F–G) Seidlitzella procera (Kraatz): (F) apical part of elytra; (G) head and pronotum, anterior view.
Figure 3 (A–D) Seidlitzella hoffeinsorum sp. nov., holotype: (A) part of metathorax, ventral view; (B) antennal club; (C) protarsi; (D) visible parts of legs, lateral view. (E–F) Seidlitzella procera (Kraatz): (E) antenna; (F) body, dorsal view.
Figure 4 Seidlitzella hoffeinsorum sp. nov., paratype: (A) dorsal view; (B) ventral view. (Photo courtesy of Jonas Damzen.)
Figure 5 Seidlitzella hoffeinsorum sp. nov.: (A) dorsal view, reconstruction; (B) mesotarsus (drawn from paratype); (C) protibial (drawn from paratype).
Type material. Holotype, sex unknown; CCHH 1753-1 [ex coll. J. Oehlke 127]. Cenozoic: Baltic amber, Eocene; found on the Baltic Sea coast, Samland Peninsula (formerly East Prussia); deposited in the amber collection of the Senckenberg Deutsches Entomologisches Institut, Muencheberg, Germany (SDEI). Paratype, sex unknown; CCHH 1753-2a; Cenozoic: Baltic amber, Eocene; obtained in Lithuania in 2016; deposited in SDEI.
Diagnosis. Seidlitzella hoffeinsorum sp. nov. differs from the extant S. procera in the following characters: (1) punctures of pronotum distinctly separated from one another and interspaces several times larger than individual punctures (interspaces not larger than diameter of punctures in S. procera); (2) small, thick seta present in middle of each of elytral puncture (elytral setae or scales absent in S. procera); (3) elytral carinae weakly beaded (not beaded in S. procera); (4) protibia with four small spines along outer edge (spines absent in S. procera); (5) smaller species, body length approximately 10 mm (S. procera larger, about 12–16 mm).
Description. Body length including mandibles about 10.5 mm (holotype) and 9.7 mm (paratype), further measurements for both specimens appear in Table 3. Body relatively compact and flattened, widest at approximately two-thirds of elytra; dorsal and ventral surfaces, legs and antennae uniformly black or black-brown. Head finely but densely punctate at dorsal and ventral surfaces, but punctures separated from each other; pronotum dorsally very finely punctate, punctures distinctly separated from one another and interspaces several times larger than individual punctures; elytra coarsely and regularly punctate, interspaces approximately as wide as diameter of punctures; each puncture bearing small, whitish, elongate scale or a thick seta. Ventral side of thorax with fine sculpture and without pubescence, abdominal ventrites densely, shortly pubescent.
Table 3 Measurements of Seidlitzella hoffeinsorum sp. nov.
Head. Eyes laterally situated, not exceeding contour of head; single pair of eyes. Antennal grooves well-developed. Ventral side of cranium with several long setae (sensillae) at sides; ctenidium area obscured by cloudy coating. Maxillary palps slender, terminal palpomere truncate at apex; terminal segment of labial palps coniform. Antenna reaching beyond mid-prothorax, with 11 sparsely pubescent antennomeres; scape robust, much larger than pedicel; antennomeres 3–8 subequal in size; loose, distinct club formed of antennomeres 9–11, asymmetrical; sensorial fields present at inner side of three terminal antennomeres.
Prothorax. Anterior margin distinctly emarginate, anterior angles projecting and acuminate; lateral carina (edge) evenly rounded, not crenulate; pronotum widest midway, basal margin rounded and without distinct denticles at lateral corners. Procoxal cavities widely separated, externally closed; prosternal process robust, its apex widely dilated.
Mesothorax. Mesocoxal cavities rounded, narrowly separated; mesonotum robust, scutum transverse, scutellum rounded. Mesothoracic wing well developed.
Metathorax. Metacoxa reaching outer margin of metepisternum; metacoxae narrowly separated. Elytron widened from humeral part towards two-thirds length, apex acute but without mucro; ten carinae, not distinctly beaded (incl. the sutural), present on each elytron (carinae weakly undulate, not perfectly straight; they may be considered weakly beaded); two rows of rounded punctures occur between each pair of carinae; epipleuron distinct in humeral quarter only, then narrowed.
Legs. Procoxa transverse; mesocoxa rounded, weakly projecting; metacoxa strongly transverse. All femora slightly clavate; protibia with four small spines along outer side, row of teeth along apex, two apical spines: one robust, hooked spine and the other straight and medium-sized; meso- and metatibia without distinct spines along outer side, with two straight apical spines. Tarsal formula 5–5–5, but seemingly 4–4–4 because basitarsus small and retracted into apex of tibia, in similar fashion to that of other members of Gymnochilini. Tarsomeres 2–4 equal, without lobes; terminal tarsomere as long as (1)2–4 together; tarsal claws large, curved, without denticles; empodium large, bisetose.
Abdomen with five finely pubescent ventrites.
Etymology. The species is named after Christel and Hans Werner Hoffeins (Hamburg, Germany) who made these fossils available for study.
Remarks. Gymnocheilis obesa (Heer, Reference Heer1862) from the middle Miocene (Sarmatian, c.12 mya) in Germany was previously the only fossil species of Trogossitidae: Gymnochilini to be described. According to the original diagnosis, “the body of G. obesa is covered with a vestiture of rounded scales, like recent species of Gymnochila (sic) from Africa” (Heer Reference Heer1862, pp 56–57, pl. 3; Heer Reference Heer1865, p. 382). The presence of distinct dorsal body vestiture distinguishes the latter species from S. hoffeinsorum sp. nov. (cf. Kolibáč Reference Kolibáč2013, p. 31, fig. 4D, E). However, it should be noted that a generic classification of G. obesa is uncertain without a more exact identification of eye number, since Gymnocheilis Dejean and Leperina are of similar habit and the dense body vestiture of scales occurs in both genera.
3. Discussion
After Promanodes serafini Kolibáč, Schmied, Wappler & Kubisz, Reference Kolibáč, Schmied, Wappler and Kubisz2010 and P. alleni Kolibáč, Reference Kolibáč2011, Seidlitzella hoffeinsorum sp. nov. is the third species of Trogossitidae to be described from Baltic amber and the oldest known representative of the tribe Gymnochilini.
The restricted eastern Mediterranean distribution of the single recent species Sedlitzella procera is unique within Trogossitidae and unusual in all Cleroidea. However, several recent, species-poor European genera have supposed relatives in New Zealand (e.g., Enoplium Latreille and Phymatophaea Pascoe) or the southernmost part of Africa (e.g., Korynetes Herbst) (Kolibáč Reference Kolibáč2014). There are also examples of a disjunct distribution between European Paleogene fossils and their extant relatives in Cleroidea (namely Trogossitidae, Rhadalidae, Cleridae), today living in North America, sub-Saharan Africa, Madagascar, southeastern Asia, temperate South America, Australia and New Zealand. For example, two species of the extinct Eocene genus Promanodes Kolibáč, Schmied, Wappler & Kubisz are supposedly related to the extant New Zealand genus Promanus Sharp (Kolibáč et al. Reference Kolibáč, Leschen, Leschen, Beutel and Lawrence2010). However, Baltic amber species of extant cleroid genera have also been described: Pseudopallenis Kuwert and Xamerpus Fairmaire (extant species on Madagascar and in eastern Africa); Cymatodera Gray and Phyllobaenus Dejean (North America); Orthrius Gorham (southeastern Asia); Thanasimodes Murray, Strotocera Schenkling and Prosymnus Laporte (Africa); and Lemidia Spinola (Chile, Argentina, Australia) (Kolibáč Reference Kolibáč1997; Kolibáč & Gerstmeier Reference Kolibáč and Gerstmeier1997; Majer Reference Majer1998).
Seidlitzella is situated at the very base of the gymnochiline clade, closely related to Melambia, Phanodesta, Leperina (incl. present Kolibacia species) in the phylogenetic analysis of Trogossitidae by Kolibáč (Reference Kolibáč2008), whilst the genus forms a polytomy with the cluster Kolibacia (Phanodesta + Leperina) in an analysis of Gymnochilini by Leschen & Lackner (Reference Leschen and Lackner2013). Yoshitomi (Reference Yoshitomi2014) suggests a relation Seidlitzella ((Kolibacia + Leperina) + Phanodesta) in his analysis of the gymnochiline “normal-eyed group”. Following the above-mentioned morphologically-based phylogenetic analyses (Kolibáč Reference Kolibáč2008; Leschen & Lackner Reference Leschen and Lackner2013; Yoshitomi Reference Yoshitomi2014), Palaearctic Kolibacia and Seidlitzella are related to Gondwanan Leperina and Phanodesta, not to the Afro-Asian “split-eyed group”. External morphological characters of S. hoffeinsorum sp. nov., namely, (1) presence of four protibial spines, (2) a possible tendency to beaded elytral carinae, (3) moderate or absent elytral vestiture, and (4) absence of window punctures (Table 2), are in agreement with a definition of the “normal-eyed group”by Leschen & Lackner (Reference Leschen and Lackner2013) and support a hypothesis about a sister relation of recently monotypic Seidlitzella and species-rich Phanodesta today distributed in New Zealand, New Caledonia, Lord Howe Island, Juan Fernandez Island and Sulawesi. As demonstrated by the fossil evidence of Seidlitzella hoffeinsorum described herein, this genus was distributed in the western Palaearctic in the Paleogene.
4. Acknowledgements
The authors extend their thanks to Christel and Hans Werner Hoffeins (Hamburg, Germany) for making the specimens available for study; to Tony Long (Svinošice) for his help with the English; and to all reviewers and editors for their valuable comments. The participation of the senior author (JK) was made possible by financial support provided to the Moravian Museum by the Ministry of Culture of the Czech Republic, as part of its long-term conceptual development programme for research institutions (ref. MK000094862). The junior author (VK) was supported by the Russian Foundation for Basic Research, project number 14-04-00262.
