Cretaceous Beetle Research Articles

An unusual Cretaceous beetle with affinity to Anamorphidae (Coleoptera: Coccinelloidea)

Coccinelloid beetles have a sparse fossil record in the Mesozoic. Here, we describe and illustrate an unusual coccinelloid beetle, Yassibum yoshitomii gen. et sp. nov., from mid-Cretaceous Kachin amber. Yassibum stands out within the Coccinelloidea due to its notched profemora and the presence of antennal grooves on the elytral epipleura. Based on our phylogenetic analyses, we suggest that Yassibum is most likely related to the family Anamorphidae. The alternative placements are critically evaluated based on our comparison of the morphology.

Cretaceous beetles of the Jinju Formation (Coleoptera): An overview of the Jinju Formation, its coleopteran diversity, and past and future research

Several Coleoptera fossils, including Coptoclavidae, Elateridae, Ommatidae, and Staphylinidae, were previously described from the Jinju Formation (Albian), South Korea. However, numerous beetle fossils require further research to fully understand the biodiversity of this important Cretaceous deposit. In this study, we present an overview of the diversity of Coleoptera from the Jinju Formation. Future studies on beetles of the Jinju Formation will be divided into several parts corresponding to the major lineages found in this Albian deposit. In this first part, we introduce the geological context, review previous studies related to Coleoptera fossils from the Jinju Formation, and present specimens that will undergo detailed examination in subsequent papers.

Prototrichalus is transferred to the Tenebrionoidea: A comment on Molino-Olmedo et al., 2020, ‘The description of Prototrichalus gen. nov. And three new species from Burmese amber supports a mid-Cretaceous origin of the Metriorrhynchini (Coleoptera, Lycidae)’

Newly available specimens of Prototrichalus Molino-Olmedo et al., 2020 yield further diagnostic characters for the phylogenetic classification of this recently described genus. We show that Prototrichalus has tarsal formula 5-5-4, short trochanters, kidney-shaped eyes; the antennae are inserted in front of eyes and palpomeres substantially differ from all net-winged beetles. These characters identify tenebrionoid families as potential relatives of Prototrichalus. For example, extant and Eocene Ischalia Pascoe, 1860 (Anthicidae: Ischaliinae) resemble Prototrichalus in the structure of elytral costae and costal interspaces. As a result, we transfer Prototrichalus from Elateroidea: Lycidae to Tenebrionoidea incertae sedis. The earlier claim that Prototrichalus pushes the origin of Metriorrhynchini beyond earlier estimates is incorrect. The radiation of major net-winged beetle lineages was estimated ~123 million years ago and the deepest splits within Metriorrhynchini to 77–98 million years ago and these estimations were not considered in the discussion on Prototrichalus. We assume that the superficial similarity in the general appearance of Prototrichalus and net-winged beetles can be a result of mimicry in already very diverse Cretaceous beetles, but only further discoveries of additional species can provide robust evidence for the convergent evolution.

Angiosperm pollinivory in a Cretaceous beetle.

Despite the crucial importance of flower-visiting insects in modern ecosystems, there is little fossil evidence on the origins of angiosperm pollination. Most reports of pollination in the Mesozoic fossil record have been based on the co-occurrence of the purported pollinators with pollen grains and assumed morphological adaptations for vectoring pollen. Here, we describe an exceptionally preserved short-winged flower beetle (Cucujoidea: Kateretidae) from mid-Cretaceous amber, Pelretes vivificus gen. et sp. nov., associated with pollen aggregations and coprolites consisting mainly of pollen, providing direct evidence of pollen-feeding in a Cretaceous beetle and confirming that diverse beetle lineages visited early angiosperms in the Cretaceous. The exquisite preservation of our fossil permits the identification of the pollen grains as Tricolpopollenites (Asteridae or Rosidae), representing a record of flower beetle pollination of a group of derived angiosperms in the Mesozoic and suggesting that potentially diverse beetle lineages visited early angiosperms by the mid-Cretaceous.

Cretophengodidae, a new Cretaceous beetle family, sheds light on the evolution of bioluminescence.

Bioluminescent beetles of the superfamily Elateroidea (fireflies, fire beetles, glow-worms) are the most speciose group of terrestrial light-producing animals. The evolution of bioluminescence in elateroids is associated with unusual morphological modifications, such as soft-bodiedness and neoteny, but the fragmentary nature of the fossil record discloses little about the origin of these adaptations. We report the discovery of a new bioluminescent elateroid beetle family from the mid-Cretaceous of northern Myanmar (ca 99 Ma), Cretophengodidae fam. nov. Cretophengodes azari gen. et sp. nov. belongs to the bioluminescent lampyroid clade, and would appear to represent a transitional fossil linking the soft-bodied Phengodidae + Rhagophthalmidae clade and hard-bodied elateroids. The fossil male possesses a light organ on the abdomen which presumably served a defensive function, documenting a Cretaceous radiation of bioluminescent beetles coinciding with the diversification of major insectivore groups such as frogs and stem-group birds. The discovery adds a key branch to the elateroid tree of life and sheds light on the evolution of soft-bodiedness and the historical biogeography of elateroid beetles.

Cretaceous beetles (Insecta: Coleoptera) in amber: the palaeoecology of this most diverse group of insects

AbstractBeetles, the most successful group of invertebrates on Earth, have a worldwide distribution and an outstanding fossil record. In addition, they are well known as inclusions in fossil resin. In historical studies of fossil material, specimens were often named and described without placing the taxa in an ecological context. However, the research philosophy for fossil beetles has changed over the past few years. In this article, we summarize the palaeoecological interpretations of fossil beetles from Cretaceous ambers, which includes species from 69 families, most of which were described during the last 3 years. By analysing current habits of those families, we argue that saproxylicity was the most common feeding strategy for these fossil beetles. More specifically, fungivorous species appear to dominate. In contrast, we find only anecdotal evidence for the presence of wood-boring groups, and it is thus necessary to identify alternative abiotic or biotic processes that are responsible for the copious resin production at this time. Finally, the recent description of some beetles as gymnosperm pollinators during the Cretaceous lends more weight to the importance of amber studies in addressing the role of beetles in the evolution of pollination strategies.

Highly specialized Cretaceous beetle parasitoids (Ripiphoridae) identified with optimized visualization of microstructures

AbstractExtremely miniaturized longipedes insects (body length c. 0.3 mm) embedded in two pieces of Cretaceous amber from Myanmar are described and interpreted. Using inverted fluorescence and light microscopy for detailed analysis of microstructures, the inclusions were identified as primary larvae of the beetle family Ripiphoridae, subfamily Ripidiinae. While the structure of thoracic and abdominal segments including appendages corresponds well with the groundplan known in recent members of Ripidiinae, a curved prosternal ridge with prominent spines (each c. 5 μm), the reduced condition of stemmata and antennae and the lack of sharp mandibles are unique features within the entire family, apparently apomorphies of the longipedes larvae. A sinuate prosternal edge with a dense row of spines (prosternoctenidium) might be homologous with ‘head ctenidia’ in some previously described miniaturized conicocephalate larvae, but further investigation is needed. The morphological differences between the head of longipedes larvae and extant Ripidiinae are interpreted as adaptations to different groups of hosts and life strategies. Palaeoethology of the longipedes larvae is briefly discussed. In addition, the systematic placement of conicocephalate larvae from Canadian, Myanmar and Russian Cretaceous ambers, already interpreted by various authors as primary instars within Coleopterida (assigned to either Strepsiptera or to the coleopteran Tenebrionoidea: Ripiphoridae), is discussed.

Brochocolein beetles (Insecta: Coleoptera) from the Lower Cretaceous of northeast China and southern England

Lower Cretaceous beetles belonging to the extinct tribe Brochocoleini (Coleoptera: Cupedidae: Ommatinae) are revised and five new species proposed in the extinct Eurasian genus Brochocoleus: Brochocoleus yangshuwanziensis sp. nov. (Yixian Formation, China); Brochocoleus crowsonae sp. nov., Brochocoleus keenani sp. nov., Brochocoleus tobini sp. nov. (Weald Clay Group, UK); and Brochocoleus maximus sp. nov. (Purbeck Limestone Group, UK). New morphological data is provided for Brochocoleus impressus and Brochocoleus sulcatus stat. nov. of which Brochocoleus angustus is considered a synonym (Yixian Fm.). The hindwing venation is described for the first time supporting the basal position of this tribe. A simple key is provided to all Cretaceous species of this presumably xylophagous, warm climate genus.

Ommatin beetles (Insecta: Coleoptera) from the Lower Cretaceous of northeast China and southern England

Lower Cretaceous beetles belonging to the extant tribe Ommatini (Coleoptera: Cupedidae: Ommatinae) are revised and six new species proposed in the extinct Eurasian genusCionocoleus:Cionocoleus tanaesp. n.,Cionocoleus olympicussp. n. (Yixian Formation, China);Cionocoleus elizabethaesp. n.,Cionocoleus watsonisp. n.,Cionocoleus minimussp. n. (Weald Clay Group, UK); andCionocoleus jepsonisp. n. (Purbeck Limestone Group, UK). New morphological data is provided forCionocoleus magicusandCionocoleus cervicalisstat. n. of whichCionocoleus planiusculusis considered a synonym (Yixian Formation).Cionocoleus punctatuscomb. n. is considered the oldest record (Upper Jurassic; Kazakhstan) of this presumably xylophagous, warm climate genus. A simple key is provided to all known species ofCionocoleus.

A new glypheid lobster from the Late Cretaceous of Hawke's Bay, New Zealand

Recognition of a fossil previously identified as a “large Cretaceous beetle” as a glypheid lobster permits the definition of a new species, Glyphea wiffenae. The specimen was collected from the richly fossiliferous, Upper Cretaceous Maungataniwa Sandstone in eastern North Island, New Zealand. Several other fossil decapods with high southern latitude affinities have been described previously from the unit, supporting the placement of the Zealandia region within the Weddellian Biotic Province. This is only the fourth glypheid known from New Zealand and the first Cretaceous occurrence of the genus in the country.

An Upper Cretaceous beetle (Coleoptera) from Hawkes Bay, New Zealand

Abstract The first New Zealand Cretaceous insect fossil, an incomplete beetle elytron, is described. The fragment is identified as belonging to a member of the suborder Polyphaga, probably either a buprestid or chrysomelid.