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.

Revisiting the morphology of the Cretaceous ommatid beetle Clessidromma palmeri (Coleoptera: Archostemata: Ommatidae)

Abstract The morphology of Clessidromma palmeri Jarzembowski et al. from mid-Cretaceous Burmese amber is revised based on a reexamination of the type specimen. Contrary to previous studies, our observation confirms that Clessidromma has open procoxal cavities. The characters such as platform on the ventral side of head, modified metacoxae, and ridges on head and pronotum are suggested to be diagnostic characters for Clessidromma. Clessidromma zengi Kirejtshuk from the same deposit is transferred into a new genus, as Kirejtomma zengi comb. nov.

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.

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.

Revisiting the morphology of the Cretaceous ommatid beetle Clessidromma palmeri (Coleoptera: Archostemata: Ommatidae)

Abstract The morphology of Clessidromma palmeri Jarzembowski et al. from mid-Cretaceous Burmese amber is revised based on a reexamination of the type specimen. Contrary to previous studies, our observation confirms that Clessidromma has open procoxal cavities. The characters such as platform on the ventral side of head, modified metacoxae, and ridges on head and pronotum are suggested to be diagnostic characters for Clessidromma. Clessidromma zengi Kirejtshuk from the same deposit is transferred into a new genus, as Kirejtomma zengi comb. nov.

Revisiting the morphology of the Cretaceous ommatid beetle Clessidromma palmeri(Coleoptera: Archostemata: Ommatidae)

The morphology of Clessidromma palmeri Jarzembowski et al. from mid-Cretaceous Burmese amber is revised based on a reexamination of the type specimen. Contrary to previous studies, our observation confirms that Clessidromma has open procoxal cavities. The characters such as platform on the ventral side of head, modified metacoxae, and ridges on head and pronotum are suggested to be diagnostic characters for Clessidromma. Clessidromma zengi Kirejtshuk from the same deposit is transferred into a new genus, as Kirejtomma zengicomb. nov.(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)

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.

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)