Earliest teredid beetle from mid-Cretaceous amber of northern Myanmar (Coleoptera: Coccinelloidea: Teredidae): new genus and species

The earliest fossil member of Teredidae, Delteredolaemus hei Li & Cai gen. et sp. nov., is reported from mid-Cretaceous Burmese amber. Delteredolaemus is assigned to the extant tribe Teredini, and shares a generally similar morphology with the extant genus Teredolaemus Sharp, 1885, although it can be distinguished from all other members in the tribe by the shape of the pronotum and mesoventral process, as well as the anteromedially tumid metaventrite.(AU)

Anomocephalobus, a new genus of minute marsh-loving beetles from mid-Cretaceous Burmese amber (Coleoptera: Limnichidae)

Limnichidae are currently a moderately diverse beetle family with a sparse fossil record. Here we describe a new limnichid genus and species, Anomocephalobus liuhaoi Li, Jäch & Cai gen. et sp. nov., from the mid-Cretaceous amber from northern Myanmar. Anomocephalobus gen. nov. is tentatively assigned to the extant subfamily Cephalobyrrhinae, based on its transverse metacoxae, 5-segmented protarsi, and absence of grooves on the ventral surface for reception of legs, though its oval body shape is somewhat deviating from extant Cephalobyrrhinae. The generic placement of the recently described Erichia cretacea Yu, Ślipiński, Ren & Pang, 2018 is also discussed.(AU)

Revisiting the morphology and systematic placement of the enigmatic Cretaceous ommatid beetle Bukhkalius lindae(Coleoptera: Archostemata: Ommatidae)

The systematic position of Bukhkalius lindae (Jarzembowski et al. 2017) from mid-Cretaceous Burmese amber is revised based on a re-examination of the type specimen. Our observations confirm that B. lindae lacks unique apomorphies of Tetraphalerus Waterhouse, in which it was originally placed, including complete antennal grooves and mushroom-shaped micro-tubercles. It is well justified to place it into a separate genus, i.e., Bukhkalius Kirejtshuk & Jarzembowski, 2020. The incomplete but distinct antennal grooves and the Tetraphalerus-like mouthparts of B. lindae suggest that it has a close affinity to Tetraphalerus. Therefore, B. lindae may represent a missing link bridging the morphological gap between extant ommatid subfamilies Tetraphalerinae and Ommatinae.(AU)

New species of Paraodontomma from mid-Cretaceous Burmese amber with muscle tissue preservation (Coleoptera: Archostemata: Ommatidae)

The third member of the extinct ommatid genus Paraodontomma is reported from mid-Cretaceous Burmese amber. Our observation confirms the transverse ridges on elytra as a diagnostic character for the genus. Paraodontomma leptocristatumsp. nov. differs from previously reported congeners mainly in head subquadrate and without prominent protuberances, pronotal disc without prominent ridges, elytral ridges indistinct, and teeth along elytral margins not forming a wavy pattern. Musculature is preserved in the newly discovered specimen of P. leptocristatum, which further demonstrates the preservation potential and irreplaceable value of amber fossils.(AU)

Revisiting the morphology and systematic placement of the enigmatic Cretaceous ommatid beetle Bukhkalius lindae (Coleoptera: Archostemata: Ommatidae)

Abstract The systematic position of Bukhkalius lindae (Jarzembowski et al. 2017) from mid-Cretaceous Burmese amber is revised based on a re-examination of the type specimen. Our observations confirm that B. lindae lacks unique apomorphies of Tetraphalerus Waterhouse, in which it was originally placed, including complete antennal grooves and mushroom-shaped micro-tubercles. It is well justified to place it into a separate genus, i.e., Bukhkalius Kirejtshuk & Jarzembowski, 2020. The incomplete but distinct antennal grooves and the Tetraphalerus-like mouthparts of B. lindae suggest that it has a close affinity to Tetraphalerus. Therefore, B. lindae may represent a missing link bridging the morphological gap between extant ommatid subfamilies Tetraphalerinae and Ommatinae.

New species of Paraodontomma from mid-Cretaceous Burmese amber with muscle tissue preservation (Coleoptera: Archostemata: Ommatidae)

Abstract The third member of the extinct ommatid genus Paraodontomma is reported from mid-Cretaceous Burmese amber. Our observation confirms the transverse ridges on elytra as a diagnostic character for the genus. Paraodontomma leptocristatum sp. nov. differs from previously reported congeners mainly in head subquadrate and without prominent protuberances, pronotal disc without prominent ridges, elytral ridges indistinct, and teeth along elytral margins not forming a wavy pattern. Musculature is preserved in the newly discovered specimen of P. leptocristatum, which further demonstrates the preservation potential and irreplaceable value of amber fossils.

A miniaturized ommatid beetle in mid-Cretaceous Burmese amber (Coleoptera: Archostemata: Ommatidae)

Recent findings of ommatids from mid-Cretaceous Burmese amber have greatly increased our knowledge on the Mesozoic diversity of Ommatidae. Here, we report the first distinctly miniaturized ommatid species, Miniomma chenkuni gen. et sp. nov., entombed in mid-Cretaceous amber from northern Myanmar. This new fossil species is characterized by its small body size (less than 2 mm long) and subglobular metacoxae. Our discovery of miniaturization in extinct Ommatidae suggests a high ecological diversity of this family in the Mesozoic.(AU)

A miniaturized ommatid beetle in mid-Cretaceous Burmese amber (Coleoptera: Archostemata: Ommatidae)

Recent findings of ommatids from mid-Cretaceous Burmese amber have greatly increased our knowledge on the Mesozoic diversity of Ommatidae. Here, we report the first distinctly miniaturized ommatid species, Miniomma chenkuni gen. et sp. nov., entombed in mid-Cretaceous amber from northern Myanmar. This new fossil species is characterized by its small body size (less than 2 mm long) and subglobular metacoxae. Our discovery of miniaturization in extinct Ommatidae suggests a high ecological diversity of this family in the Mesozoic.

A miniaturized ommatid beetle in mid-Cretaceous Burmese amber (Coleoptera: Archostemata: Ommatidae)

Abstract Recent findings of ommatids from mid-Cretaceous Burmese amber have greatly increased our knowledge on the Mesozoic diversity of Ommatidae. Here, we report the first distinctly miniaturized ommatid species, Miniomma chenkuni gen. et sp. nov., entombed in mid-Cretaceous amber from northern Myanmar. This new fossil species is characterized by its small body size (less than 2 mm long) and subglobular metacoxae. Our discovery of miniaturization in extinct Ommatidae suggests a high ecological diversity of this family in the Mesozoic.