Research Article |
Corresponding author: Michael Schmitt ( michael.schmitt@uni-greifswald.de ) Academic editor: Jorge Santiago-Blay
© 2016 Andris Bukejs, Michael Schmitt.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Bukejs A, Schmitt M (2016) Lilioceris groehni sp. n.: the first authentic species of Criocerinae (Coleoptera, Chrysomelidae) from Baltic amber. ZooKeys 618: 67-77. https://doi.org/10.3897/zookeys.618.10085
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Based on a single well-preserved specimen from Eocene Baltic amber, Lilioceris groehni sp. n. is described and illustrated using phase-contrast X-ray microtomography. It is the first described species of Criocerinae (Coleoptera: Chrysomelidae) from Baltic amber. A check-list of fossil Criocerinae is provided. Placement of Crioceris pristiana (Germar, 1813) is discussed, this species is removed from Criocerinae and placed in Coleopteraincertae sedis.
Taxonomy, palaeontology, shining leaf beetles, new species, Crioceris pristiana , fossil resin, Tertiary, Eocene
The subfamily Criocerinae (shining leaf beetles) contains ca. 1500 extant species (
Shining leaf beetles are rarely represented in fossil material and especially in Baltic amber (Table
Taxon | References | Fossil Type | Locality | Age |
---|---|---|---|---|
Criocerinae |
|
Baltic amber | Kaliningrad region (Russia) | 37.2–33.9 Ma |
Criocerinae |
|
poorly lithified peat | Mizozono Formation, Yoshimatsu-cho, Kagoshima Prefecture (Japan) | 0.1–0.0 Ma |
Crioceridea dubia |
|
lacustrine shale | Florissant, Colorado (USA) | 37.2–33.9 Ma |
Crioceris margarum |
|
lacustrine shale | Aix-en-Provence (France) | 28.4–23.0 Ma |
Crioceris vetusta |
|
lacustrine shale | Oeningen (Germany) | 12.7–11.6 Ma |
Crioceris sp. |
|
Baltic amber | Kaliningrad region (Russia) | 37.2–33.9 Ma |
Lema evanescens |
|
lacustrine shale | Florissant, Colorado (USA) | 37.2–33.9 Ma |
Lema fortior |
|
lacustrine shale | Florissant, Colorado (USA) | 37.2–33.9 Ma |
Lema lesquereuxi |
|
lacustrine shale | Florissant, Colorado (USA) | 37.2–33.9 Ma |
Lema tumulata |
|
terrestrial siliciclastic | Salzhausen (Germany) | 15.9–11.6 Ma |
Lema sp. |
|
Baltic amber | Kaliningrad region (Russia) | 37.2–33.9 Ma |
Lema sp. |
|
lacustrine shale | West Cumberland (England) | 0.1–0.0 Ma |
(?)Lema sp. |
|
unlithified siliciclastic sediments | Achchagyai-Allaikha Yana–Indigirka Lowland, nord-east Siberia (Russia) | 0.1–0.0 Ma |
Lilioceris groehni | present paper | Baltic amber | Kaliningrad region (Russia) | 37.2–33.9 Ma |
Coleoptera incertae sedis | ||||
Crioceris pristina |
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Baltic amber | Kaliningrad region (Russia) | 37.2–33.9 Ma |
Crioceris sp. and Lema sp. were mentioned from Eocene Baltic amber without detailed species descriptions (
The specimen is included in an amber piece that was polished by hand and facetted on their sides, allowing improved views of the included specimens. The material examined is deposited in the collection of the Geological-Palaeontological Institute of the
Observations were made using a Nikon SMZ 745T stereomicroscope. Photographs were taken using a Canon EOS 70D with a 100 mm macro lens, and a Canon EOS 5D with the Canon MP E 65 mm macro lens in a visionary digital bk plus lab system by Dun Inc. The microCT-images were produced by means of an Xradia Micro XCT-200 (Carl Zeiss X-ray Microscopy Inc.), using the 4x object lens units, at 30kV and 4W, with a pixel size of 5.36 µm. Tomography projections were reconstructed using the reconstruction software provided by XRadia. Volume rendering of image stacks was performed by using Amira 5.6.0 (FEI Visualization Science Group, Burlington, USA) using the “Volren” or “Voltex” function.
The specimen considered here was assigned to the family Chrysomelidae based on the pseudoteramerous tarsi and the lack of a rostrum and of antennae not inserted on pronounced tubercles, to the subfamily Criocerinae because the prothorax does not bear side borders and the frons has distinct diverging grooves behind the antennal insertions, and to the genus Lilioceris based on (1) free tarsal claws and (2) divided vertex separated from the neck by a dorsal constriction.
Holotype: Nr. “C 8130” [
Baltic amber, mid-Eocene to Upper Eocene.
Yantarny settlement (formerly Palmnicken), Sambian (Samland) Peninsula, the Kaliningrad region, Russia.
Head, body, and elytra of Lilioceris groehni sp. n. appear unicolorous black and thus similar to the extant species L. hitam Mohamedsaid, 1990 from Borneo, which differs from the new species in (1) the shape of the pronotum (distinctly longer than wide with its constriction at the middle), (2) metaventrite glabrous in the middle, (3) pubescent scutellum, (4) impunctate elytra (with few moderately large punctures at base only), (5) vertex with sparse pubescence, (6) a distinct conical neck between head and pronotum, and (7) a larger body (10 mm).
Additionally, the extant species L. lilii Scopoli, 1763 and L. merdigera Linnaeus, 1758 from Baltic region differ from L. groehni sp. n. in having (1) a pronotum with a longitudinal row of punctures medially, (2) metaventrite, metepisternum and ventrites of abdomen almost glabrous or with very sparce pubescence, and (3) pronotum and elytra rufous to red.
Holotype. Body length 7.1 mm, maximum width 4.1 mm; elongate, subparallel, moderately convex dorsally and ventrally, unicolorous black, glabrous dorsally.
Head hypognathous, transverse, widest across eyes, together with eyes nearly as wide as pronotum, strongly constricted behind the eyes forming a neck (Fig.
Pronotum nearly as long as wide, deeply constricted medially, distinctly narrower than elytra, widest in anterior one-third; impunctate, shiny; disc flattened, with an arcuate transverse depression subbasally (Figs
Scutellum large, triangular; apparently hairless and impunctate. Elytra subparallel, widest in the middle, about 1.5 times as long as wide; humeri prominent. Elytral punctures small and dense (in basal one-third deeper), arraged in rows; scutellar row present, short; intervals flat, only at apices weakly convex.
Metaventrite with sparse, fine pubescence; metepisternum and metepimeron densely covered with fine, short, semierect pubescence. Abdomen with sparse, fine pubescence.
Legs moderately long, covered with fine pubescence. Femora spindle-shaped; tibiae slightly curved, dilated apically. Tarsi long, about 0.7 times as long as tibia; metatarsomeres 1–2 subequal in length, distinctly dilated apically, metatarsomere 3 deeply bilobed, metatarsomere 4 subcilyndrical, narrow. Tarsal claws free, not fused at base.
The interior of the abdomen does not contain any identifiable structure, as revealed by the microCT-analysis. No traces of an aedeagus could be found, and none of the smaller particles – all covered with homogeneous material – could be addressed as the spermatheca.
This new species is named after Carsten Gröhn (Glinde, Germany) – he enabled us to study this specimen.
The specimen of Lilioceris groehni sp. n. appears externally complete. However, the fact that we found no traces of internal structures in the abdomen, especially of an aedeagus, does most probably mean that (1) the specimen was a female, and (2) that it remained openly accessible for scavengers and/or detritivores before it was covered by resin. This could also provide a possible reason for its black appearance as the dead individual might have been exposed to humic acids before being fossilised. If this should be the case, the live animal had most probably a habitus similar to the extant lily beetles. Actually, L. groehni sp. n. is hardly distinguishable from extant Lilioceris-species. In this respect, the new species is quite normal.
Few Quaternary sub-fossil records contain specimens of the extant species: Lema cyanella (Linnaeus, 1758) from La Taphanel, Massif Central, France (Ponel and Coope 1990); Lema trilinea White, 1981 from late Quaternary Kaetan Cave, Colorado Plateau, Colorado, USA (
The authors are grateful to Carsten Gröhn (Glinde, Germany) for the loan of interesting fossil material, to Vitalii I. Alekseev (Kaliningrad, Russia) for valuable suggestions and constructive advice, to Peter Michalik (Greifswald, Germany) for invaluable help with macro-imaging and the microCT-analysis, and the German Science Foundation (DFG) for financial support (INST 292/119-1 FUGG, INST 292/120-1 FUGG).