Balticeler kerneggeri gen. nov., sp. nov., an enigmatic Baltic amber fossil of the ground beetle subfamily Trechinae (Coleoptera, Carabidae)

Balticeler kerneggerigen. nov., sp. nov., is described based on six fossil specimens preserved in Eocene Baltic amber and imaged using light microscopy and X-ray micro-computed tomography. Based on certain characters observed in the fossil species it is considered a “middle grade” Carabidae, outside of the large family Harpalinae (as it possesses a scrobal seta, the lack of which is a synapomorphy of that subfamily), but possessing four synapomorphies that indicate Balticeler belongs to a large clade of carabids including Harpalinae (anisochaetous Grade B antennal cleaner, conjunct mesocoxae, closed procoxal cavities, and a well-developed external lobe of the metepimeron). This remarkable beetle has several striking features, including lack of externally-visible sexually dimorphic characters, lack of lateral borders on the pronotum, and very long and thin mandibles and maxillae. In combination, these states are unique within Carabidae. We consider the presence of a dorsally completely open aedeagal median lobe as a synapomorphy of the fossil species with the subfamily Trechinae, a pubescent and relatively long second antennomere and a 4+2+2 pattern of umbilicate setae as synapomorphies of the supertribe Trechitae, and a quadrisetose clypeus as a synapomorphy with the Trechitae clade Bembidarenini + Trechini sensu Maddison et al. (2019). As it lacks a synapomorphy of Bembidarenini + Trechini, we propose that it is a member of the stem group of that clade.

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A new fossil Eurypinae genus and sexual dimorphism in the representatives of Omineus (Coleoptera: Mycteridae) from Tertiary amber of Europe

Zootaxa ◽

10.11646/zootaxa.4820.3.8 ◽

2020 ◽

Vol 4820 (3) ◽

pp. 551-562

Author(s):

VITALII IGOREVICH ALEKSEEV ◽

ANDRIS BUKEJS ◽

DARREN ANDREW POLLOCK

Keyword(s):

Computed Tomography ◽

Sexual Dimorphism ◽

Baltic Amber ◽

Micro Computed Tomography ◽

Fossil Species ◽

X Ray ◽

Secondary Sexual Characters ◽

Kaliningrad Region ◽

First Time ◽

Secondary Sexual

Europoeurypus inglaeso gen. et sp. nov. is described from Eocene Baltic amber found on the Sambian Peninsula, Kaliningrad Region, Russia. Four additional specimens of mycterid beetles from collections of Baltic amber are reported. The secondary sexual characters and sexual dimorphism in the Eocene representatives of the genus Omineus Lewis, 1895 are documented for the first time and examined using X-ray micro-computed tomography (μCT). The studied Omineus male specimens were attributed to the fossil species Omineus febribilis Alekseev, Pollock & Bukejs, 2019. A key to fossil species of Eurypinae from Eocene ambers is provided and several aspects of the biogeography of the subfamily Eurypinae are discussed.

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The first described fossil species of Litargus Erichson (Coleoptera: Mycetophagidae) from Eocene Baltic amber examined with X-ray microtomography, and new records of Crowsonium succinium Abdullah, 1964

Zootaxa ◽

10.11646/zootaxa.4768.3.7 ◽

2020 ◽

Vol 4768 (3) ◽

pp. 405-414

Author(s):

VITALII I. ALEKSEEV ◽

JANUSZ KUPRYJANOWICZ ◽

KRISTAPS KAIRIŠS ◽

ANDRIS BUKEJS

Keyword(s):

Computed Tomography ◽

New Records ◽

Original Description ◽

Baltic Amber ◽

Micro Computed Tomography ◽

Fossil Species ◽

X Ray ◽

Incertae Sedis ◽

The Family ◽

A New Species

A new species of Mycetophagidae belonging to the genus Litargus, namely L. (Litargosomus) dantiscensis Alekseev, Kupryjanowicz et Bukejs sp. nov., is described and figured from Eocene Baltic amber using X-ray micro-computed tomography (μCT). Three additional specimens of a mycetophagid beetle that is rather common in Baltic amber, Crowsonium succinium Abdullah, are also reported. Prototoma striata Heer, which was originally placed in Mycetophagidae, is discussed based on its original description and illustration: it is proposed that the position incertae sedis within Coleoptera be given to this Early Jurassic fossil. Consequently, the records of Mycetophagidae from Eocene European amber should be considered the earliest occurrence of the family known to date.

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First fossil representative of Cerylonidae (Coleoptera: Coccinelloidea) described using X-ray micro-computed tomography, from Eocene Baltic amber

Zootaxa ◽

10.11646/zootaxa.5032.2.4 ◽

2021 ◽

Vol 5032 (2) ◽

pp. 225-236

Author(s):

ANDRIS BUKEJS ◽

ADAM ŚLIPIŃSKI ◽

JERIT L. MITCHELL ◽

RYAN C. MCKELLAR ◽

MAURICIO BARBI ◽

...

Keyword(s):

Computed Tomography ◽

New Species ◽

Baltic Amber ◽

Micro Computed Tomography ◽

Extinct Species ◽

X Ray ◽

The Family

Based on material originating from five amber collections of Eocene Baltic amber, Protostomopsis pandema gen. et sp. nov. is described and illustrated using X-ray micro-computed tomography. It is the first formally described extinct species of Cerylonidae, and the first known Palaearctic representative of the subfamily Ostomopsinae. As such, the new species extends the temporal range of the family Cerylonidae by approximately 45 Ma.

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Description of the first flightless platynine ground beetle preserved in Baltic amber (Coleoptera: Carabidae)

Zootaxa ◽

10.11646/zootaxa.4318.1.4 ◽

2017 ◽

Vol 4318 (1) ◽

pp. 110

Author(s):

JOACHIM SCHMIDT ◽

TORBEN GÖPEL ◽

KIPLING WILL

Keyword(s):

Computed Tomography ◽

New Species ◽

Type Species ◽

Ground Beetle ◽

Species Level ◽

Baltic Amber ◽

Monotypic Genus ◽

X Ray ◽

X Ray Computed ◽

A New Species

Species of the megadiverse ground beetle tribe Platynini occur on all continents except Antarctica. It has been long recognized that platynine beetles were preserved in the Eocene Baltic amber. However, thus far only a single Eocene fossil has been described to the species level. In the present paper, a new species of Platynini known only as an amber inclusion fossil is described and imaged using light microscopy and micro X-ray computed tomography. Since this species cannot be assigned to any of the recently described genera, the monotypic genus Praeanchodemus gen. n., with the type species P. punctaticeps sp. n., is erected. There is some evidence from external morphology that Praeanchodemus gen. n. is part of a lineage comprising the recent genera Paranchodemus, Rhadine, and Tanystoma. However, since some synapomorphies were not found, the true relationships of the fossil taxon remain moot.

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The first extinct species of <i>Acritus</i> LeConte, 1853 (Histeridae: Abraeinae) from Eocene Baltic amber: a microscopic beetle inclusion studied with X-ray micro-computed tomography

Fossil Record ◽

10.5194/fr-24-223-2021 ◽

2021 ◽

Vol 24 (2) ◽

pp. 223-231

Author(s):

Vitalii I. Alekseev ◽

Andris Bukejs

Keyword(s):

Computed Tomography ◽

Light Microscopy ◽

Baltic Amber ◽

Micro Computed Tomography ◽

Absolute Size ◽

Male Specimen ◽

Current Finding ◽

X Ray ◽

Size Limits ◽

Average Size

Abstract. Acritus sutirca sp. nov. is described and illustrated from Eocene Baltic amber on the basis of one adult male specimen. As the first extinct member of the subfamily Abraeinae (Histeridae) and the smallest known fossil histerid specimen, this material was examined using a combination of light microscopy and X-ray micro-computed tomography (µCT). Internal features of the abdomen are well preserved, allowing us to study sclerotized parts of the aedeagus and illustrate these structures in detail. The current finding expands the range of known Histeridae diversity from the Eocene (48–34 Ma) “amber forests” of Europe. The absolute size limits and the probable average size for Baltic amber coleopteran inclusions are also briefly discussed (urn:lsid:zoobank.org:pub:A2B17479-8628-47C7-A8D4-3E0789BF088B).

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Diversification through gustatory courtship: an X-ray micro-computed tomography study on dwarf spiders

Frontiers in Zoology ◽

10.1186/s12983-021-00435-8 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Shou-Wang Lin ◽

Lara Lopardo ◽

Gabriele Uhl

Keyword(s):

Computed Tomography ◽

Sexual Selection ◽

Anterior Part ◽

Divergent Evolution ◽

Sexually Dimorphic ◽

Ancestral State ◽

Glandular Tissue ◽

Micro Computed Tomography ◽

Nuptial Gifts ◽

X Ray

Abstract Background Sexual selection has been considered to promote diversification and speciation. Sexually dimorphic species have been used to explore the supposed effect, however, with mixed results. In dwarf spiders (Erigoninae), many species are sexually dimorphic—males possess marked prosomal modifications. These male traits vary from moderate elevations to bizarre shapes in various prosomal regions. Previous studies established that male dwarf spiders produce substances in these prosomal modifications that are taken up by the females. These substances can act as nuptial gifts, which increase the mating probability of males and the oviposition rate in females. Therefore, these dimorphic traits have evolved in the context of sexual selection. Here, we explore the evolutionary lability of this gustatory trait complex with the aim of assessing the role of this trait complex in species divergence by investigating (1) if erigonine modified prosomata are inherently linked to nuptial-gift-producing glands, (2) if the evolution of the glands evolution preceded that of the modified prosomal shapes, and by assessing (3) the occurrence of convergent/divergent evolution and cryptic differentiation. Results We reconstructed the position and extent of the glandular tissue along with the muscular anatomy in the anterior part of the prosoma of 76 erigonine spiders and three outgroup species using X-ray micro-computed tomography. In all but one case, modified prosomata are associated with gustatory glands. We incorporated the location of glands and muscles into an existing matrix of somatic and genitalic morphological traits of these taxa and reanalyzed their phylogenetic relationship. Our analysis supports that the possession of glandular equipment is the ancestral state and that the manifold modifications of the prosomal shape have evolved convergently multiple times. We found differences in gland position between species with both modified and unmodified prosomata, and reported on seven cases of gland loss. Conclusions Our findings suggest that the occurrence of gustatory glands in sexually monomorphic ancestors has set the stage for the evolution of diverse dimorphic external modifications in dwarf spiders. Differences among congeners suggest that the gland position is highly susceptible to evolutionary changes. The multiple incidences might reflect costs of glandular tissue maintenance and nuptial feeding. Our results indicate divergent evolutionary patterns of gustatory-courtship-related traits, and thus a likely facilitating effect of sexual selection on speciation.

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Description of the male of fossil <i>Calomicrus eocenicus</i> Bukejs et Bezděk (Coleoptera: Chrysomelidae: Galerucinae) from Eocene Baltic amber using X-ray microtomography

Fossil Record ◽

10.5194/fr-23-105-2020 ◽

2020 ◽

Vol 23 (1) ◽

pp. 105-115 ◽

Cited By ~ 1

Author(s):

Andris Bukejs ◽

Jan Bezděk ◽

Vitalii I. Alekseev ◽

Kristaps Kairišs ◽

Ryan C. McKellar

Keyword(s):

Body Size ◽

Body Cavity ◽

The Body ◽

Baltic Amber ◽

Sexually Dimorphic ◽

Apical Margin ◽

Fossil Species ◽

X Ray ◽

Total Body ◽

First Time

Abstract. A male representative of the extinct species Calomicrus eocenicus Bukejs et Bezděk, 2014 (Chrysomelidae: Galerucinae) is found and described for the first time from Eocene Baltic amber using X-ray microtomography. The aedeagus is well preserved within the body cavity of the specimen, and it is illustrated in detail. This fossil species exhibits distinct sexual dimorphism: the male has a smaller total body size, as well as a copula-adapted modification in abdominal ventrite 5 (apical margin deeply trilobed, with round medial fovea present); meanwhile the female is larger in body size and has a simple abdominal ventrite 5 (without fovea, non-incised and widely rounded apically). Similar sexually dimorphic characters are typical for extant members of the tribe Luperini, and this report is the first time that they are described in an Eocene species. The known sexually dimorphic characters present in Coleoptera within Eocene Baltic amber are briefly discussed.

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Unexpected findings in the Eocene Baltic amber forests: Ground beetle fossils of the tribe Nebriini (Coleoptera: Carabidae)

Zootaxa ◽

10.11646/zootaxa.4701.4.2 ◽

2019 ◽

Vol 4701 (4) ◽

pp. 350-370

Author(s):

JOACHIM SCHMIDT ◽

STEFAN SCHOLZ ◽

DAVID H. KAVANAUGH

Keyword(s):

Ground Beetle ◽

Sister Group ◽

Climatic Conditions ◽

Baltic Amber ◽

New Taxon ◽

Micro Computed Tomography ◽

X Ray ◽

The Baltic ◽

Unexpected Findings ◽

Warm Temperate

Occurrence of the ground beetle tribe Nebriini in the Baltic amber forest is confirmed. The nebriine taxon Archaeonebria inexspectata gen. n., sp. n., is described and imaged based on four fossil specimens preserved in the Eocene Baltic amber using light microscopy and X-ray micro-computed tomography. The new taxon shares likely synapomorphies with the amphipacific genus Nippononebria and is therefore proposed as its sister group. The occurrence of Archaeonebria in the Baltic amber forests supports previous assumptions that these forests grew under temperate, at least warm-temperate, climatic conditions.

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The first extinct species of Monolepta Chevrolat (Coleoptera: Chrysomelidae: Galerucinae) from Bitterfeld amber, described using X-ray micro-computed tomography

Zootaxa ◽

10.11646/zootaxa.4995.2.7 ◽

2021 ◽

Vol 4995 (2) ◽

pp. 345-356

Author(s):

ANDRIS BUKEJS ◽

JAN BEZDĚK ◽

KRISTAPS KAIRIŠS ◽

VITALII IGOREVICH ALEKSEEV

Keyword(s):

Computed Tomography ◽

Female Specimen ◽

Micro Computed Tomography ◽

Fossil Species ◽

Extinct Species ◽

X Ray ◽

Unique Character ◽

Fossil Resin

Based on a well preserved female specimen from Bitterfeld amber, Monolepta rappsilberi sp. nov. is described and illustrated using X-ray micro-computed tomography (μCT). It is the second reported member of Chrysomelidae from this fossil resin and the first described fossil Monolepta representative. The fossil species represents a lineage that is extinct in Recent Europe. A longitudinal carina on abdominal ventrite 5 of the female is a unique character for the subfamily Galerucinae.

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Diversification Through Gustatorial-Courtship: An X-ray Micro-Computed Tomography Study on Dwarf Spiders

10.21203/rs.3.rs-594155/v1 ◽

2021 ◽

Author(s):

Shou-Wang Lin ◽

Lara Lopardo ◽

Gabriele Uhl

Keyword(s):

Computed Tomography ◽

Sexual Selection ◽

Anterior Part ◽

Sexually Dimorphic ◽

Ancestral State ◽

Glandular Tissue ◽

Micro Computed Tomography ◽

Evolutionary Patterns ◽

X Ray ◽

Outgroup Species

Abstract BackgroundSexual selection has been considered to promote diversification and speciation. Sexually dimorphic species have been used to explore the supposed effect, however, with mixed results. In dwarf spiders (Erigoninae), many species are sexually dimorphic - males possess marked prosomal modifications. These male traits vary from moderate elevation to bizarre shapes in various prosomal regions. Previous studies established that male dwarf spiders produce substances in these prosomal modifications that are taken up by the female. Since the transfer of substances increases mating probability of males and oviposition rate in females, the dimorphic traits evolved in the context of sexual selection. Here, we explore the evolutionary lability of the gustatory trait complex by investigating 1) if erigonine modified prosomata are inherently linked to nuptial-gift-producing glands, 2) if gland evolution preceded that of the modified prosomal shapes and by assessing 3) the probability of convergent evolution and cryptic differentiation - with the aim of assessing the role of this trait complex in species divergence.ResultsWe reconstructed the position and extent of the glandular tissue along with the muscular anatomy in the anterior part of the prosoma of 76 erigonine spiders and three outgroup species using X-ray micro-computed tomography. We incorporated the location of glands and muscles into an existing matrix of somatic and genitalic morphological traits of these taxa and reanalyzed their phylogenetic relationship. Our analysis supports that possession of glandular equipment is the ancestral state. The manifold modifications of the prosomal shape have evolved convergently multiple times. We found differences in glandular position between species with both modified and unmodified prosomata, and reported on seven cases of gland loss. ConclusionsOur findings suggest that the occurrence of gustatory gland in sexually monomorphic ancestors has set the stage for the evolution of diverse dimorphic external modifications in dwarf spiders. Variation among congeners indicates that glandular position is highly susceptible to changes. Multiple incidences of gland loss suggest considerable maintenance costs of glandular tissue and nuptial feeding. Our results demonstrate divergent evolutionary patterns of gustatorial-courtship-related traits, and a likely facilitating effect of this type of sexual selection on speciation

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