Palaeoentomology

Cretaceous Spanish amber: History, research and checklist of taxa

ENRIQUE PEÑALVER — 2025-04-29

The present work is a checklist of taxa described or cited from bioinclusions preserved in Spanish amber outcrops (nine type localities). All these bioinclusions are Albian in age (ca. 110–102 Ma), except for a few from a Cenomanian outcrop. All the listed taxa are arthropods (mostly insects), with the exception of some plant parataxa and plant palynomorphs. The present checklist of taxa has been elaborated 30 years after the first bioinclusion was discovered in Spain, thus virtually it spans over 30 years of study by a Spanish team (AMBERIA) thanks to a series of national projects funded by the Spanish Ministry of Science and other public institutions as the Natural Science Museum of Álava (Provincial Council of Álava), and the Government of Cantabria together with the semi-public enterprise EL SOPLAO S.L. The list comprises 7 classes (or similar rank), 24 orders (or similar rank), 101 families, 169 genera and 186 species (including the plant parataxa). Eight families, 104 genera (implicating a total of 104 type species) and 184 species were described based on 184 holotypes from Spanish amber. We provide all the relevant data for each taxon, focusing on new families, genera and species described based on Spanish bioinclusions, pretending to be as useful and readable as possible.

The first record of omaliine rove beetles (Coleoptera: Staphylinidae: Omaliinae) in Eocene Rovno amber

ALEXEY V. SHAVRIN — 2025-04-24

The Omaliinae, a relatively large rove beetle subfamily, contains more than 1,700 extant species in about 120 genera and 23 extinct species in 17 genera (including 10 extinct genera). Omaliinae is currently composed of seven tribes (Newton, 2022). Among the fossil omaliines, twelve species are known from amber deposits (Shavrin et al., 2025): the Baltic amber (10 species in 6 genera), mid-Cretaceous Charentese amber (one species in one extinct genus), and the Dominican amber (one species in one genus). The anthophilous Eusphalerum Kraatz, 1857 is the single genus of the tribe Eusphalerini Hatch, 1957 and contains 270 extant species, distributed in the Holarctic Region, with several species known from the northern part of the Oriental Region (Newton, 2022). The tribe Eusphalerini can be recognized from other tribes of omaliines by the presence of broadened tarsomeres 1–4 with dense and long ventral setae, the morphology of the aedeagus and female accessory sclerites, and by some other features (Zanetti, 1987, 2014). Some species have modified elytra, sometimes they are sexually dimorphic (females of some species have strongly elongate elytra, sometimes covering entire length of the abdomen); some species have modified shape of the apical abdominal tergites, etc. (e.g., Zanetti, 1987). To date, two subgenera are known in the genus (Zanetti, 2014): the nominative subgenus and Pareusphalerum Coiffait, 1959. Several groups of species were established based on a set of some external and internal morphological features (e.g., Zanetti, 1987, 2014). Adults of Eusphalerum are known as pollen-feeders and live on flowers of different plants (Klinger, 1983). Only some other taxa in Omaliini have such trophic preferences: Amphichroum Kraatz, 1857, some species of Paraphloeostiba Steel, 1960, Xanthonomus Bernhauer, 1926, etc.

Paleocene amber from Sanshui Basin

MICHAEL SERIO — 2025-04-24

Globally, amber-rich strata are primarily found in major geological intervals, particularly the Aptian-Albian of the Early Cretaceous and the Eocene, both of which coincide with greenhouse climate conditions (Pearson et al., 2007; Katz et al., 2008; Delclòs et al., 2023). However, despite the relatively warm temperatures of the Paleocene, amber from this epoch remains exceptionally rare, with no confirmed records reported to date. This scarcity may be linked to the limited exposure of Paleocene strata worldwide. The Late Cretaceous Canadian Big Muddy amber deposit (ca. 67 Ma) which represents one of the closest known occurrences to the K-Pg boundary (Loewen et al., 2024). Here, we report the first-ever discovery of Palaeocene amber from the Sanshui Basin, China, filling a critical gap in the fossil resin record.

Discovery of late Eocene amber from the Maoming Basin, Guangdong Province

XIANG-BO SONG — 2025-04-24

The Eocene was characterized by globally warm climates and high biodiversity, making Eocene amber a valuable resource for reconstructing palaeoenvironment and continental palaeobiota. The Maoming Basin in West Guangdong Province, South China, preserves a rich fossil record of Eocene-Oligocene biota, indicative of a humid subtropical climate. Here we report two distinct amber types from the Youganwo Formation of Maoming Basin, found in Huidang village and Yezi village, respectively. The first type, from Huidang village, represents the most abundant and largest amber specimens documented in Guangdong to date, preserved alongside fragments of angiosperm leaves. The second type, from Yezi village, occurs as infills within plant resin/gum ducts, preserved with resin-producing fossilized wood. These findings highlight the Maoming Basin as a significant locality for the late Eocene biota, providing crucial insights into biodiversity and enhancing our understanding of Eocene palaeoecology and palaeoclimate in the region.

A new genus of the extinct family †Holopsenellidae (Hymenoptera, Aculeata) from the mid-Cretaceous Burmese amber

ANDERSON LEPECO — 2025-04-29

Aculeata is a clade including all ants, bees, and a large array of stinging wasps. In recent years, the systematics of these groups has been changed substantially by molecular phylogenetics, directly impacting our understanding about their evolution. Regardless, the paleontology of Aculeata still imposes many challenges, including enigmatic groups that cannot be confidently linked to any extant lineage. One of these lineages corresponds to the family †Holopsenellidae, which represents one of the earliest representatives of Aculeata in the fossil record. The single known genus, †Holopsenella, was first described from Early Cretaceous Lebanese amber, being also recorded in the younger Burmese amber. In the present work, we describe †Typhopsenella obscura gen. et sp. nov., based on an inclusion from Burmese amber, representing the second genus known for the family. This wasp is remarkable for its size, being far larger than †Holopsenella and also in relation to the overall size of wasps described from amber inclusions. Further evidence supporting the removal of †Holopsenellidae from Chrysidoidea is raised. Novel records of the family may turn out to be imperative for understanding its phylogenetic affinities among other stinging wasps.

Ichnotaxonomy of new boring taxa: linking insect activity and fossil resins formation

BŁAŻEJ BOJARSKI — 2025-04-29

The fossil record reveals palaeoecological interactions between plants and insects. This study describes a singular conifer xylite specimen from the Baltic amber-bearing deposits, with preserved resin ducts and cylindrical insect borings designated as Bivium ichnogen. nov. with Bivium diluviandi ichnosp. nov. The borings, characterized by longitudinal tunnels connected by cross tunnels and chambers, were likely created by xylophagous beetles belonging to the family Curculionidae (subfamily Scolytinae). The associated resin production reflects an adaptive plant response to insect and fungal activity, evidenced by fungal hyphae preserved within the specimen. This work contributes to the knowledge of Baltic amber stratigraphy, and the formation of resin-bearing deposits, and shows, that the wood-boring insects may have been a cause, among others, of resin exudation.

New damselflies (Odonata: Zygoptera: Burmacoenagrionidae) from mid-Cretaceous Myanmar amber

YU-XUAN LIU — 2025-04-29

A new species Electrocoenagrion rarissimum sp. nov. of Burmacoenagrionidae is described from mid-Cretaceous Burmese amber. It is assigned to this family by having its typical characteristics: 12–19 postnodal crossveins present; Pt 3–5 short cells long; pterostigmal part of RA and stigmal crossveins thickened to form U-shaped structure; RP1 with weak angle below Pt-brace. Electrocoenagrion rarissimum sp. nov. differs from the other two species of this genus by RP2 originating seven cells distad of Sn, 19–20 postnodal crossveins present basad of Pt in forewing, midfork distinctly distad of N and Arc distad of Ax2. A revised diagnosis of Electrocoenagrion is provided, with a detail description of head and wing base structure.

**The second species of Lobanoviella Kirejtshuk & Reid, 2021 (Coleoptera: Megalopodidae) in Eocene amber**

VITALII ALEKSEEV — 2025-04-29

A new extinct species of Palophaginae (Coleoptera: Megalopodidae), Lobanoviella lethebibens sp. nov., is described and illustrated based on inclusions in Eocene Baltic and Rovno ambers. This second species of the genus known from the European palaeofaunas can be distinguished by the larger and wider body, by the pronotal shape, elytral punctures arranged in regular longitudinal rows and lateral subvertical stripes of the elytral slopes much wider and widening to apices.

**New data on Caririlabia berghoffi Haas, 2007, and redescription of Cratoborellia gorbi Haas, 2007 (Dermaptera: Neodermaptera), earwigs from the Lower Cretaceous of the Araripe Basin**

EDINARDO DA SILVA SANTOS — 2025-04-29

The Brazilian Crato Formation, located in Araripe Sedimentary Basin, is renowned for its excellent fossil preservation, making it as a significant Cretaceous Konservat-Lagerstätte. Among the diverse groups recorded from this formation, Insecta stands out, boasting over 400 described species, including six species of Dermaptera. This study redescribes Cratoborellia gorbi Haas, a Dermaptera species from Araripe Basin, based on a single, nearly complete and well-preserved male specimen from the Lower Cretaceous Crato Formation, Araripe Basin, Brazil. It adds important morphological characteristics to the taxonomy of the species and distinguishes it from other fossil genera in the region. Opportunity is taken to report an additional specimen of the very rare Caririlabia berghoffi Hass, previously known only from the holotype.

**Two new species of Trentepohlia (Paramongona) (Diptera: Limoniinae) from Mexican amber (Miocene)**

DAUBIAN SANTOS — 2025-04-29

Trentepohlia Bigot is a cosmopolite and diverse genus, including both current and extinct species. Its fossil record includes Baltic, Burmese, Dominican, Mexican, and Sumatra ambers, as well as in fossil compressions. In this study, we described two more species of Trentepohlia from Miocene Mexican amber, including illustrations and an updated identification key for fossil Trentepohlia (Paramongoma). We also compare the new species with previously fossil species described in the genus, discussing their morphology, paleobiology, and systematics.