Search

\nHighlightsA new and intriguing fossil Mallomonas species, M. enigmata, was uncovered from 10 strata in the Eocene Giraffe Pipe locality. The new species represents an ancient member of the section Punctiferae, and based on scale and bristle morphology is most closely related to the modern congener, M. nieringii. M. nieringii is a rare species known from a suite of acidic waterbodies on the Cape Cod peninsula, Massachusetts, USA. Only a few modifications of the body scales differ between M. enigmata and M. nieringii, and the new taxon was uncovered from a section of the Giraffe Pipe maar lake representing a shallow and acidic waterbody. Cysts of M. enigmata are oval, with a small pore surrounded by a narrow hyaline zone. The anterior ~ ¼ of the cyst surrounding the hyaline zone consists of a series of small, closely spaced, rimmed holes that penetrate the wall. Otherwise, the cyst wall is smooth and unornamented. Unlike any known modern species in the genus, a second type of body scale is produced, but found only attached to the cyst. It is hypothesized that these scales may represent unfinished body scales that became fused to the cyst during its development. A new fossil Eocene species of Mallomonas.A unique second scale morphotype attached to the cyst.Thrived in a shallow, humic and acidic freshwater pond.A new fossil Eocene species of Mallomonas.A unique second scale morphotype attached to the cyst.Thrived in a shallow, humic and acidic freshwater pond. [ABSTRACT FROM AUTHOR]

The remains of a unique fossil bony fish were discovered in late Eocene (39.1–36.7 Ma: NZ Kaiatan stage) mudstone at Burnside near Dunedin, New Zealand in the 1930s and subsequently named and described by Frederick Chapman. He interpreted the type specimen as being a large-scaled relative of the modern Thyrsites of the Gempylidae (Scombroidei: Trichiuroidea), known to be swift, large oceanic predators. However, Chapman is unlikely to have seen all of the fossil, and did not discuss the skull and caudal skeleton. Additional material now allows these to be included in the expanded description herein, including key morphologic features of the fish such as the presence of premaxillary fangs. This study describes the rather complex history of the specimen and re-examines this significant fossil fish in the University of Otago collections, giving a more complete understanding of Eothyrsites morphology, paleoecology and relationships. In summary, we suspect Eothyrsites represents an ancestral form of gempylid, closely related to the gemfish group, an important Southern Hemisphere macrofossil record from the Eocene seas around Zealandia. [ABSTRACT FROM AUTHOR]

The small, primitive 'oreonetine' oreodonts from the late Eocene (Chadronian) of North America have long been a systematic mess with gross oversplitting, failure to recognise post-mortem distortion of specimens and many errors in their descriptions. We describe some new fossils and review the group for the first time since 1956. Of the six genera and nine species recognised by Schultz & Falkenbach (1956), only three genera (Oreonetes, Limnenetes, and Bathygenys) and six species are now considered valid. The 'Oreonetinae' is a paraphyletic wastebasket group because some members are closer to more derived oreodonts than others, and Limnenetes is a primitive leptauchenine, not a merycoidodontine. These small, rare late Eocene oreodonts found only in Wyoming, Montana, and Texas are the precursors to the enormous radiation of oreodonts in the early Oligocene. [ABSTRACT FROM AUTHOR]

Histological structure of long bones from bony-toothed birds (Odontopterygiformes) from Early Lutetian locality Ikove (Ukraine) is examined for the first time. Six limb bones from Pelagornithidae cf. Dasornis sp. and Lutetodontopteryx tethyensis are described. The bones, although usually being fragmented, show good preservation at the microscopic level. Their microstructure (e.g. orientation and diameter of primary osteons) significantly varies, but the basic pattern and, therefore, the way of growth matches that of recent Neognathae (as well as a number of extinct taxa). In young birds, the periosteum quickly deposited well-vascularised primary bone, which at the same time was resorbed from inside, then the animal reached adult size and fast bone growth gave way to much slower deposition of circumferential layers of lamellar or parallel-fibred tissue on the outer and inner bone surfaces. The bones also underwent Haversian remodelling of various extent (from nearly absent to nearly full), generally stronger in larger bones and in the inner compacta. Bone microstructure is consistent with high metabolic rates, expected in Odontopterygiformes, and implies that their growth rates were comparable to those of recent Neognathae. [ABSTRACT FROM AUTHOR]

Palaeogene South American faunas include enigmatic ungulates that cannot be classified unequivocally within any of the main South American (SA) Native Ungulates clades (Litopterna, Notoungulata, Astrapotheria, Pyrotheria and Xenungulata) because they retain plesiomorphic features, resembling Laurasian ‘archaic ungulates’ traditionally classified within the order ‘Condylarthra’. Most SA ‘condylarths’ are known by partial dental series and isolated teeth and unassociated postcranial remains, hampering comparisons with better-known ungulates. Here, we describe a nearly complete skull and associated mandible of an SA ‘condylarth’, Talquinodus puertai gen. et sp. nov., preserving most of the dentition and basicranium, derived from middle Eocene rocks of the Sarmiento Formation at Central Patagonia. Talquinodus shows a combination of plesiomorphic traits (complete dentition with bunolophodont cheek teeth, ring like ectotympanic, retention of stapedial system, etc.), combined with some autapomorphies, as the reduction of the m3 talonid. Our phylogenetic analyses support consistently that Talquinodus belongs to the SA radiation of Euungulata along with Litopterna, Notoungulata and Astrapotheria. However, the internal relationships could not be resolved unambiguously: Talquinodus could be a didolodontid related to the origin of Litopterna, or could be part of a separate radiation of South American archaic ungulates, along Depaulacoutoia, Lamegoia and Escribania, with no descendants in post-Eocene faunas. [ABSTRACT FROM AUTHOR]

Examples of the small beetle family Cerylonidae are scarcely represented in the fossil record or at least are rarely determined as such by specialists. Until now, only one species of an extinct genus has been reliably identified to this family from Eocene Baltic amber. A new species, Mychocerus gedanensis McHugh et Ślipiński, sp. nov. (Coleoptera, Cerylonidae), is described from Eocene Baltic amber using X-ray micro-computed tomography (μCT) and optical microscopy. This is the first extinct species described for the subfamily Ceryloninae. It belongs to the extant genus Mychocerus Erichson, 1845, the largest cerylonid genus, which has a widespread distribution that until now excluded the continental parts of the Palaearctic. The new fossil species can be placed in the North American discretus group with two remarkably similar species (M. discretus (Casey, 1890) and M. striatus Sen Gupta & Crowson, 1973) based on the presence of a long and parallel-sided prosternal process. LSID: urn:lsid:zoobank.org:act:95EA100C-3323-472C-A17B-B75480B3FB18 [ABSTRACT FROM AUTHOR]

Two leafy liverwort species from the late Eocene Rovno amber are described. They are placed in the extant genus Nipponolejeunea (Jubulaceae, Porellales, Marchantiophyta) that includes two extant East Asian species and one fossil species described from the Eocene Baltic amber. New fossil species N. rovnoi sp. nov. and N. solodovnikovii sp. nov. differ from the Baltic N. europea, thus making the extinct diversity of the genus exceeding the contemporary species diversity, and such a case is registered for the first time for liverworts. The finding of Nipponolejeunea in Rovno amber may indicate the presence of Abies in the Eocene of Ukraine, since at the southern border of its distribution in Japan extant species the genus grows only on fir trunk. This is in a good concordance with the recent finding in Rovno amber the longhorn beetle Poliaenus europaeus, also associated with fir trees. [ABSTRACT FROM AUTHOR]

A new species of narrow-waisted bark beetle is described from Eocene Rovno amber (Ukraine): Diagrypnodes villumi sp. nov. (Coleoptera: Salpingidae). This fossil refutes a simplistic view of the genus Diagrypnodes as a typical Gondwanan lineage whose extant species are disjunct between Australia, New Caledonia, and New Zealand. Diagrypnodes villumi is the first definitive fossil species of the subfamily Inopeplinae, the other being Eopeplus stetzenkoi Kirejtshuk and Nel from lowermost Eocene (53 Ma) Oise amber which was placed in this subfamily, albeit tentatively. Extant inopeplines occur in tropical and subtropical areas worldwide. The presence of Diagrypnodes and Eopeplus in Eocene Europe suggest a formerly different and presumably wider distribution of the subfamily. Furthermore, the ant Lasius schiefferdeckeri Mayr (Hymenoptera: Formicidae) preserved in the amber piece as a eusyninclusion with D. villumi is a new example of the simultaneous presence of the temperate and frost intolerant elements in European Eocene amber forests.LSID [ABSTRACT FROM AUTHOR]

A new species of soldier beetle (Cantharidae) from Eocene Baltic amber, Malthodes maierae sp. nov., is described and illustrated from a male specimen discovered in Russia. The new species differs from the hundreds of known extant and extinct species of Malthodes Kiesenwetter, 1852. The last abdominal segments, which are substantially modified on the male to hold the female during mating, differ considerably in Malthodes species and are very important diagnostic elements for this genus. The exact evolutionary forces driving these manifold modifications are unknown, but they are likely related to sexual selection, mate recognition, antagonistic coevolution, or varying habitats, or a combination of two or more of these factors.The Zoobank LSID for this is: urn:lsid:zoobank.org:pub:DC13FC31-BD71-4C3D-9536-B70AF65FB699 [ABSTRACT FROM AUTHOR]

In this first report on the re-investigation of the Eocene Messel palynoflora using combined light- and scanning electron microscopy, comprising Algae to Vitales, it is shown that this epic paleoflora can still provide new insights into the ancient ecosystem prevailing at that time. Applying this combined single-grain method on the palynomorphs enabled us to identify several new floral elements represented in the palynoflora, as well as to revise previous spore/pollen classifications, resulting in a higher taxonomic resolution of the microflora. So far, we have discovered three different algae remains, 28 spore types, and pollen from seven different gymnosperms and 26 unique angiosperms. Some of the new taxa include Lycopodiaceae, Cycadales, Stratiotes (Hydrocharitaceae), and Poaceae. The spore/pollen flora was compared to the meso/macroflora, revealing the importance of combining meso/macrofossil records with state-of-the-art microfossil analyses for a more holistic representation of the paleoflora. This is reflected in the number of taxa only occurring in the microflora (ten families) versus that of the meso/macroflora (18 families). Comparing the results from this qualitative combined light- and scanning electron microscopy study to classical quantitative light microscopy methods already suggests that the combined method provides a higher diversity of spore/pollen taxa. Still, potential floral newcomers could be missed in such single sample investigations that are otherwise detected in the classic up-trough section analyses. [ABSTRACT FROM AUTHOR]

A new elasmobranch assemblage including 14 shark taxa, mainly lamniformes (9 taxa), is described from the Lower Eocene (NP 10–11) Kalinino Formation of the Alai River Basin, Baltai District, Saratov Region of Russia. The Nikulinka elasmobranch assemblage may have characterised inner neritic environments of the eastern part of the sub-boreal European paleobiogeographic region, being closely related to assemblages from the south-most sector of the boreal Western Siberian Province (southern Trans-Urals and Turgay straight). The absence of myliobatids in Nikulinka and Trans-Uralian localities may have been caused by the influence of Arctic water masses through meridional straits in early Ypresian. This is the first chondrichthyan assemblage from the Palaeogene of the Middle Volga Region, European Russia. [ABSTRACT FROM AUTHOR]

Frogs (Anura) are major components of tetrapod communities in the Neotropics and, according to divergence-time estimates, were already diverse in early Palaeogene times, but this is still poorly documented in the fossil record. A late Eocene frog assemblage from the Geste Formation exposed at Antofagasta de la Sierra (Catamarca province) is here described, providing a first glimpse into the Palaeogene anuran diversity in the present-day Puna of north-western Argentina. The assemblage is composed by at least four hyloid neobatrachian taxa having miniature to large body-sizes, ranging 17–81 mm estimated snout-vent length. Neither the families currently found in the Puna-Altiplano, nor those from the Cretaceous – Eocene of southern South America, are represented. The assemblage comprises possible brachycephaloids, odontophrynids, and hemiphractids, suggesting climatic and environmental conditions very different from the harsh conditions prevailing today in the Puna-Altiplano and a biogeographical link with Amazonia. The joint presence of these taxa is currently restricted to the nearby Austral Yungas and the Atlantic Forest, suggesting that the late Eocene frogs likely inhabited a humid forest. The new frog assemblage constitutes a rare window to the early evolution of Neotropical anurans and a major leap forward in the palaeoenvironmental reconstruction of the Puna during Eocene times. [ABSTRACT FROM AUTHOR]

Rhaphoneis amphiceros (Ehrenberg) Ehrenberg is one of the commonest extant rhaphoneid diatoms and has been reported from multiple fossil deposits, but our work suggests this taxon may not be as common in the fossil assemblages as indicated by the literature. Indeed, the original description of the species, made by Ehrenberg, is not as detailed as modern descriptions, which can lead to confusion when identifying taxa. Recent studies show that diatom species previously reported to occur over time intervals of tens of millions of years may actually represent groups of taxa lumped together due to inaccurate identifications. In this article, we present two new species that, without careful SEM examination, can be confused with R. amphiceros. These new species, interpreted to represent two new genera in the Rhaphoneidaceae, were found in middle Eocene sediments from Ocean Drilling Program (ODP) Hole 1050A (30°06'N, 76°14.1'W), drilled on Blake Nose, western North Atlantic. Rhomboneis shtapovii Figus & Witkowski and Rosaforma paillesiae Figus & Witkowski show unique morphological characteristics that lead us to create new genera. Rhomboneis shtapovii has two rimoportulae per valve and an unusual type of velum occluding the areolae. Rosaforma paillesiae has a peculiar asymmetric apical pore field occupying half the valve pole, the other half contains a rimoportula with two apical pores. [ABSTRACT FROM AUTHOR]

The Vacan fauna was defined by the fossil mammalian content of the Vacan Member (Sarmiento Formation) at Cañadón Vaca fossil locality (Chubut Province, Argentina), although several other local faunas from nearby areas (e.g. Río Chico oeste) were also attributed to the Vacan age estimated ca. 45–42 Ma time interval. This fauna contains poorly understood native South American ungulates, such as the Henricosborniidae. This group includes Henricosbornia, Peripantostylops, Othnielmarshia, Simpsonotus, Orome, and Nanolophodon, but both its definition and phylogenetic relationships remain unclear. In particular, Othnielmarshia and Peripantostylops were established as guide taxa of the Vacan fauna, but their knowledge has remained obscure since more than 50 years. The re-study of the Ameghino's collection and the specimens collected by the Scarritt Pocket Expeditions in Cañadón Vaca and other nearby localities allows us to 1) provide an update on the systematic status of Othnielmarshia and Peripantostylops; 2) emend their diagnoses; 3) establish comparisons with other related taxa from the same period, proposing synonymies; and 4) recognise both taxa in several local faunas from the Sarmiento and Las Flores formations. We also highlight the variability in certain controversial characters of henricosborniids, which should be evaluated for the definition of the group. [ABSTRACT FROM AUTHOR]

Phorusrhacidae, commonly known as terror birds, constitutes a group of Cariamiformes that lived mainly in South America during the Cenozoic. The oldest record is represented by an isolated distal end of tibiotarsus (MLP-PV 75-II-3-22) discovered in the Lutetian (middle Eocene) levels of the Sarmiento Formation exposed in the Cañadón Vaca locality (Chubut Province, Argentina). Despite being frequently cited as the oldest specimen of Phorusrhacidae, this specimen has never been figured or comprehensively described. Motivated by this gap and recognising the significance of this finding, we conducted a detailed comparison of the tibiotarsus MLP-PV 75-II-3-22 with those of other species, assigning it to an indeterminate species of Psilopterinae with an estimated body mass of approximately 5 kg. Furthermore, following the identification of numerous tooth marks on the distal surface, we hypothesised that this small phorusrhacid may have been subjected to an attack or scavenging event by a small-to-medium predator, such as Nemolestes spalacotherinus, a hypercarnivorous marsupial previously recorded in the Cañadón Vaca assemblage. [ABSTRACT FROM AUTHOR]

Late Eocene artiodactyl and creodont tracks have been reported from the Jianchuan Basin, southeastern Tibetan Plateau, representing the first and the oldest reported mammal tracks in Yunnan Province, China. Sedimentary facies analysis indicates that tracks from the upper Baoxiangsi Formation and the lower Shuanghe Formation occurred in lake shore and flood plain environments, respectively. Based on the morphological analysis, the artiodactyl tracks from the Baoxiangsi Formation are attributed to Anoplotheriipus zeuctus. Combined with fossil records and morphological characteristics, the artiodactyl and creodont tracks were probably produced by entelodonts and mesonychids, respectively. The superimposition of artiodactyl tracks with varying sizes indicates coexistence of juveniles and adults as well as their gregarious behaviour. The co-occurrence of artiodactyl tracks and creodont tracks suggests the predator–prey relationship and ecological chain during the late Eocene. The presence of mammal tracks in the Jianchuan Basin coincides with the climate change from dry to wet in the late Eocene, implying the climatic and ecological effects of the uplift of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Eloeophila is a genus of Limoniidae (subfamily Limnophilinae) with 85 extant valid species. So far, only one fossil species has been described: Eloeophila moba Podenas, from Baltic amber (Eocene). Here we have described other species from Baltic amber: Eloeophila eocenica sp. n. We also found that Cladura maculata, an Eocene species described by Scudder in 1894, from Florissant, Colorado, USA, actually belongs to Eloeophila. This species was renamed Eloeophila scudderi nom. nov. With these changes, Eloeophila now has three fossil species. [ABSTRACT FROM AUTHOR]

Based on an inclusion in Baltic amber, the first extinct species of the genus Hyperisus Mulsant and Rey, 1863 (Ptinidae: Ernobiinae: Xestobiini), namely H. carstengroehni sp. nov. is described. This new fossil Eocene species differs from extant European congeners in having the dorsal pubescence of two types; the lesser body size; the abdominal ventrite 5 punctate; the dorsal pubescence evenly dense; the antennal club longer than antennomeres 1–8 combined; and in the details of dorsal punctation. Provisional biogeographical affinities of the described Baltic amber Ptinidae (as of July 2023) are briefly analysed. All 20 extant genera known in Baltic amber (100% of analysed assemblage) still inhabit Holarctic of Recent. The ptinid assemblage of Baltic amber is almost twice closer in the composition of genera to the extant fauna of Palearctic or Nearctic than to other regions. Possible explanations are proposed for the abundance of death-watch beetles in Baltic amber. [ABSTRACT FROM AUTHOR]

The article describes a new species of a fossil sarcoptid mite, Sarcoptes kutchensis n. sp. extracted from a dissolved slab of amber, from the Umarsar Lignite Mine of the Kutch Basin. The fossil is a remarkable representative of forest litter biota, well-preserved in amber and represents the oldest group of mites from the equatorially placed Eocene forest, dominated by broad-leaved Dipterocarpaceae trees and shares similar taxonomic features with the present day genus of Sarcoptes, Latreille, 1802. The species is recognised by dense microfoveolate striations, lack of cuticular spines on the dorsal surface with morphological resemblance to Trixacarus, Sellnick, 1944, particularly in terms of monodactyly. The fossil is derived from an ancient group of forest litter biota which gradually evolved to higher trophic levels including association with vertebrates. Scanning Electron Microscopy (SEM) is used to highlight diagnostic characteristics including capitulum and partially concealed legs with sensory suckers, crucial for defence against large faunal predators. [ABSTRACT FROM AUTHOR]

The beetle family Ptilodactylidae is recorded for the first time from Rovno amber, Ukraine. Ptilodactyla odnosum Telnov, Perkovsky, Kundrata and Bukejs sp. nov. and a male of P. eocenica Kundrata, Bukejs and Blank, 2021 are described and illustrated using X-ray micro-computed tomography. Our discoveries of two species in Rovno amber together with recently published findings in Baltic amber and Bembridge Marls suggest that ptilodactylids were rather diverse in Eocene Europe. Identification key to Ptilodactylidae described from European Eocene ambers is provided, and relationships of the Baltic and Rovno amber coleopterofaunas are briefly discussed. [ABSTRACT FROM AUTHOR]

A new extinct handsome fungus beetle species of the extant Palaearctic genus Leiestes Chevrolat, L. tomaszewskae Alekseev and Bukejs sp. nov., is described from the Baltic amber. The new species is studied and illustrated in detail using X-ray micro-computed tomography (μCT). A list of described Endomychidae known from fossil resins (Baltic, Bitterfeld, Oise and Burmese ambers) is compiled. [ABSTRACT FROM AUTHOR]

Two new extinct species of false skin beetles (Biphyllidae) are described and illustrated based on inclusions in Baltic amber: Biphyllus lar sp. nov. and Coelodiplus uuu-impressa gen. et sp. nov. The new Eocene fossils are compared with the related extant and extinct representatives of the family. A new monotypic genus is erected for one fossil; another Eocene species is classified within the extant genus Biphyllus Dejean, 1821. The holotype of Diplocoelus probiphyllus Vitali, 2010 (Baltic amber) is re-examined and its diagnosis is emended. The present paper brings the total number of described biphyllid species from European succinite to three. A key to all documented fossil species of the family is provided. Several aspects of insect use as paleoenvironment and climate proxies are briefly discussed. On the basis of the revealed biphyllid palaeofauna and analysis of the climatic extremes of the modern distribution of the family in the Northern Hemisphere, the lowest possible annual temperature in the area of amberiferous forests of Eocene Northern Europe is hypothesised. [ABSTRACT FROM AUTHOR]

Two new species of the genus Demimaea from the subfamily Curculioninae are described from Rovno amber. Demimaea zherichini n. sp. is similar to the extant Demimaea mori but differs by its black antennae and tarsi, larger body, body lacking dense, white setae, sparsely not coarsely punctate pronotum and its narrower elytral interstriae. Demimaea gratshevi n. sp. differs from D. zherichini n. sp. by its smaller body, its comparatively longer scape extending towards the compound eye and its convex and wide elytral interstriae. This is the first fossil record of the subtribe Demimaeina. Assumptions are made about the presence of Moraceae plant species in the Eocene of Northern and Eastern Europe, particularly the genus Ficus. LSID urn:lsid:zoobank.org:pub:D89E9989-37B6-4E71-9D6E-8D616DAD2C75 [ABSTRACT FROM AUTHOR]

The first cerambycid from Eocene Rovno amber, Poliaenus europaeus n. sp. (Lamiinae, Pogonocherini) is described. The new species is the first known fossil of Poliaenus Bates, 1880, as well as the first representative of this genus in Europe. Relations with extant species and with the putative hosts of this fossil are discussed, leading to suppose the presence of Abies in Eocene of Ukraine. urn:lsid:zoobank.org:pub:0E67C646-09FE-4789-94A5-313EAB48B797 [ABSTRACT FROM AUTHOR]

The members of the family Lepidopsocidae (Psocodea: Trogiomorpha) are commonly known as scaly-winged barklice based on the presence of scales on body and wings. Interestingly, the members of the subfamily Thylacellinae, which is the sister group to the remaining members of the family, lack scales and are characterised by densely setose body and wings. We describe the thylacelline Parathylacella oisensis gen. et sp. nov. from the Eocene amber of Oise (France), corresponding to the only known fossil genus of the family. We compare it with the other genera in the subfamily. It shows a similar habitus to the genus Thylacella, and both may be closely related. The description of the new taxon increases the poorly known palaeodiversity of the lepidopsocids. We comment on the putative palaeobiology of this group and discuss new insights into the palaeobiogeography and early diversification of the subfamily Thylacellinae. An association between the thylacelline barklice and Detarieae (Fabaceae: Caesalpinioideae) trees is plausible. The biogeographic distribution might be partially explained by this association, combined with oceanic currents. Studies on Cretaceous lepidopsocids, as well as other Cenozoic specimens, are crucial to understand the evolution of this group over time, and the possible vicariance process. [ABSTRACT FROM AUTHOR]

Diacodexeids are widely considered to be a paraphyletic group consisting of the oldest and most primitive artiodactyls that made their sudden appearance in all northern continents around the Palaeocene–Eocene boundary. In South Asia, the first record of artiodactyls is marked by the appearance of Gujaratia indica from the early Ypresian (∼55 Ma) Cambay Shale of the Vastan lignite mine, India, which is slightly younger than the oldest artiodactyls from Europe and North America. Here we describe new dental material of G. indica, documenting associated upper dentition, including P4, a new locus. Gujaratia (including G. pakistanensis and G. indica) is clearly distinct from all known diacodexeids in having the most triangular upper molars and lower molars with weaker paraconids. Cladistic analysis performed to assess the phylogenetic relationships of Gujaratia with other diacodexeids, dichobunoids, raoellids and pakicetids shows that Gujaratia is monophyletic while Diacodexis and Diacodexeidae are strongly polyphyletic. Gujaratia is found to be closer to the North American diacodexeids and D. gigasei and D. morrisi from Europe, which form a paraphyletic group. The European Diacodexis represents an unnatural grouping with D. antunesi being most closely related to a clade comprising dichobunids and homacodontids, and D. gazini and D. varleti occupying basal positions in a clade comprising raoellids and pakicetids. Dichobunidae is also recovered as a polyphyletic group whereas Homacodontidae is paraphyletic. Raoellids and pakicetids, long considered to be endemic to the Indian subcontinent, are monophyletic and without close affinities to Gujaratia, and appear to be more closely allied to some European dichobunoids, e.g., D. gazini, necessitating a reappraisal of current ideas about artiodactyl origins. [ABSTRACT FROM AUTHOR]

Four specimens of the same species of scolopendromorph centipede from Eocene Baltic amber provide the first fossil occurrence of the family Plutoniumidae, a clade represented by seven extant species. The fossil material, documented by light microscopy and computed microtomography, is assigned to the genus Theatops Newport, 1844, which currently has a disjunct distribution in temperate North America, the Mediterranean region, and central China. The Eocene species is diagnostically distinct from extant congeners and is formally described as Theatops groehni sp. nov. Phylogenetic analysis of combined morphological and molecular data for three loci finds T. groehni to be nested within crown-group Plutoniumidae. The discovery of T. groehni constrains the minimal divergence date for crown-group Plutoniumidae and is consistent with hypotheses regarding the extent and nature of tropical to warm temperate European forests during the Eocene. The fossil reinforces the hypothesis that the distribution of Plutoniumidae, once more geographically widespread, has been pruned by extinction. [ABSTRACT FROM AUTHOR]

Striatochelys baba gen. et sp. nov. is a new pan-trionychid from the middle–upper Eocene (late Bartonian–Priabonian, 39–35 Ma) of the Na Duong Basin in northern Vietnam. It represents one of the best documented and most completely known Palaeogene pan-trionychid species from Asia. Striatochelys baba can be diagnosed by: (1) its relatively small size; (2) the absence of a preneural; (3) the presence of well-developed straight ridges on the costals and neurals in adults; (4) ridges more strongly developed posteriorly than anteriorly; and (5) entoplastron callosity in the shape of a bulge. A phylogenetic analysis recovers S. baba within Pan-Trionychinae in an unresolved polytomy with species of the genus Nilssonia. In addition, comparisons of the new taxon with plastomenids, pan-trionychids from the Palaeogene and extant trionychids from Asia demonstrate a particularly close resemblance to Nilssonia spp. Based on the close resemblance between S. baba and 'Trionyx' impressus (a pan-trionychid from the Maoming Basin of southern China), we here assign the latter species to the new genus Striatochelys. The close relationship between S. baba gen. et sp. nov. from the Na Duong Basin and S. impressa comb. nov. from the Maoming Basin further supports the hypothesis that a close connection between both localities existed, as already exemplified by other faunal elements such as pan-geoemydids and crocodylians. [ABSTRACT FROM AUTHOR]

Here we describe a new notoungulate taxon, Pascualhyrax irqi sp. nov., from Eocene levels of north-western Argentina. The materials studied include cranial and dental remains and were exhumed in sediments of the Quebrada de los Colorados Formation, corresponding to the late middle Eocene (Bartonian). General traits of the referred specimens (e.g. hypsodont postcanines, nasal bulge) point to a close relationship with different typotherian taxa traditionally included among the paraphyletic 'Archaeohyracidae'. In turn, a combination of characters indicates that the new material represents a new taxon (e.g. smaller size, deep ectoflexus in upper molars in all wear stages, maxillary process extending posterior to the caudal end of the nasals). A phylogenetic analysis was performed, based in a previously published matrix and the addition of new characters, resulting in a close relationship of Pascualhyrax irqi sp. nov. with different 'Archaeohyracidae' of Oligocene radiation. This fact shows the early expression of some characters until now only known for later forms, and developed in the context of a recently acknowledged diversity of hypsodont typotherians in north-western Argentina. Regarding other evolutionary issues, the strong similitude of the juvenile specimens referred to Pascualhyrax irqi sp. nov. with adult individuals of the Neogene clade Pachyrukhinae, indicates possible heterochronic (paedomorphic) traits in the later forms. [ABSTRACT FROM AUTHOR]

We report a new genus and species of Entelodontidae, Entelodontellus zhouliangi gen. et sp. nov. The new taxon is represented by a pair of mandibular halves which belong to the same individual. The left mandible preserves three molars and the right half preserves p4–m3. It can be distinguished from other entelodonts by presenting a large robust posterior mandibular tubercle, and a primitive dental morphology with a distinct paraconid and hypoconulid on m3. Phylogenetic analyses were carried out. Ten taxa and 10 characters were added to a previously published total-evidence matrix to produce a more comprehensive understanding of entelodontid phylogeny. Our phylogenetic analyses reveal that E. zhouliangi is positioned as one of the most basal taxa of Entelodontidae, inconsistent with the hypothesis that Eoentelodon is the ancestor of all the other entelodonts. The phylogenetic analyses also show that the family Entelodontidae is nested in Cetancodontamorpha, which is one of the four major radiations of Artiodactyla. It is more closely related to hippopotamus and cetaceans than to Suina. [ABSTRACT FROM AUTHOR]

The taxonomic composition, phylogeny, ecology, biology, behaviour, and fossil record of Proteininae Erichson, 1839 is reviewed to place the first Eocene fossil specimen from Baltic amber in the knowledge framework of this rove beetle subfamily. The Baltic amber fossil is a poorly preserved female which was examined using X-ray micro-computed tomography (μ-CT). It is assigned to the genus Proteinus Latreille, which is represented by 53 extant species in the world fauna, most of which occur in the north temperate areas of the globe. Due to a shortage of data, this newly discovered fossil could not be identified to the species level. However, it is the first known fossil of Proteinus, which indicates that the genus has been present since at least the Late Eocene. Together with other fossils, and what is so far known about the phylogeny of Proteininae and allied groups, it suggests that while the subfamily Proteininae dates back at least to the mid-Cretaceous, its species-rich lineages may be significantly younger. Open questions about the evolution of Proteininae, including reasons for the mainly bipolar geographical distribution of its extant members or the imbalanced diversity with recent Proteinus and Megarthrus from Proteinini being the only species-rich taxa with a global distribution, are discussed. Proteinus sp. from Baltic amber is a valuable piece of evidence for future research in this direction. [ABSTRACT FROM AUTHOR]

This study aimed to resolve the taxonomy of cassid gastropods from the upper Eocene Ocala Limestone based on specimens collected from Florida Museum of Natural History locality AL004. In 1890, Dall described a specimen from this formation, collected in a nearby county as Phalium globosum (subfamily Phaliinae). However, further collection of cassids from AL004 suggested the presence of more than one morphologically distinct taxon. Eocene cassids are particularly interesting because that is presumably the time when cassids experienced rapid diversification, which has implications for the evolutionary history of echinoid-cassid predator–prey interactions. Based on 75 specimens from AL004, it appears that the specimens interpreted as belonging to two or more morphologically distinct taxa are more likely members of a single species with extreme morphological variability, redescribed here as Semicassis globosum. Results of morphometric analyses using nine qualitatively defined cassid morphotaxa (subfamily Phaliinae) suggest that S. globosum is characterised by high intraspecific variability in shell morphology that may reflect high ecophenotypic variability or elevated intraspecific genetic variability. This study highlights the challenges associated with delineating species status using low numbers of specimens, as a dearth of diagnostic material may lead to taxonomic "over-splitting," thereby resulting in an inflated estimate of biodiversity. [ABSTRACT FROM AUTHOR]

A new genus and species of Monotomidae, Rovnoeurops mckellari gen. et sp. nov., placed in the tribe Europini, is described and figured from Late Eocene Rovno amber. An extinct monotomid genus is documented in Cenozoic amber for the first time. Rovnoeurops gen. nov. can be distinguished from 27 extant genera of Europini by the combination of the following characters: distinct, short pubescence of dorsum, neck constriction behind eyes absent, short temples, stout antennae, 2-segmented antennal club, finely crenulate lateral pronotal margins, pronotum with median impression, regular elytral punctation, long femoral lines and intercoxal process of abdominal ventrite 1 widely rounded. [ABSTRACT FROM AUTHOR]

†Antephilorhizus zerovae Kirichenko-Babko & Perkovsky sp. nov., the second species of this genus, is described from the Rovno amber (Ukraine). The new species is rather similar to the A. pripiatiensis Kirichenko-Babko & Perkovsky, 2021. The new taxon is compared with lebiines from Baltic amber. Based on a new data, the diagnosis of the genus †Antephilorhizus Kirichenko-Babko, 2021 is clarified and a key to both species of genus is given. [ABSTRACT FROM AUTHOR]

Studies of minute fossils trapped in amber shed light on the chronology of species and allow us to track evolutionary, ecological and biospheric changes. However, the resolution of commonly used methods for imaging amber fossils is limited, and the quality of preservation is not the only reason for this limitation. We have used super-resolution confocal laser microscopy (Airyscan) to study fossil mites (Acari) from the Eocene and Cretaceous amber (35–100 Ma). Here we report our technical approaches and methodological findings, including the selection of mounting medium, clearing of specimens, the effects of hydration of fossils in amber and the advantages of super-resolution confocal microscopy in obtaining images with sub-micron detail. Our results show that modern microscopy, in combination with specific non-destructive methods of amber preparation, can facilitate achieving image resolutions that were previously hardly feasible in fossils. [ABSTRACT FROM AUTHOR]

Hystricognath rodents arrived in South America from Africa during the Paleogene. The oldest South American rodents (Caviomorpha) were intensively studied in recent years. One of these assemblages is the caviomorph paleofauna from Santa Rosa, Peru. Their age was originally estimated as ?Eocene. Here, we report new caviomorph fossils from Santa Rosa and review the previously described rodents taking into account new dates and updated caviomorph information. We identified 18 genera and 22 species, including one new genus and species (Vucetichimys pretrilophodoncia gen. et sp. nov.), and two new species (Shapajamys minor sp. nov. and Ucayalimys amahuacensis sp. nov.). All taxa are brachydont, with visible cusps, and thin crests. The Santa Rosa rodents are one of the oldest and the most diverse caviomorph paleofaunas known from low latitudes of South America. Similarities between these caviomorphs and other Paleogene assemblages lead us to propose an early Oligocene age for those rodents from the Yurúa River (Brazil) and a close temporal relationship with the oldest known levels from Contamana. This new biochronological scenario has deep implications in the origin and early evolution of caviomorphs. A middle Eocene? entrance of one or several waves of African rodents arriving in South America is possible. [ABSTRACT FROM AUTHOR]

†Protosyngnathus sumatrensis is known from six specimens from Eocene lacustrine deposits of the Sangkarawang Formation of Sumatra, Indonesia. The fish was named almost 150 years ago, but has never been well described or figured. Probably because of this, it has not been included in phylogenies of extant pipefishes and seahorses (Syngnathiformes). A detailed description is provided, along with a new phylogenetic analysis of morphological characters that allows the Eocene fish to be confidently placed with the extant families Syngnathidae (pipefishes and seahorses) and Solenostomidae (ghost seahorses) along with the Paleocene marine fossil †Eekaulostomus cuevasae from Mexico. The vast majority of these fishes are marine inhabitants, with a few syngnathids entering brackish or freshwater habitats. †Protosyngnathus documents the occurrence of syngnathiform fishes in a lacustrine environment, indicating that this lineage invaded and became adapted to the freshwater environment early in the evolution of this group. [ABSTRACT FROM AUTHOR]

A new species, Archaeosciaphilus gyrommatus n. sp. of the subfamily Entiminae, is described from Baltic amber. The new species is similar to A. marshalli but differs in the smaller body sizes, the scape reaching middle of the eye, narrower decumbent elytral scales, weakly convex elytral interstriae and tarsal claws equal in length. The genus Archaeosciaphilus , n. placem. is transferred from the tribe Sciaphilini to the tribe Polydrusini. A list of species from the subfamily Entiminae described from Baltic amber is given. The relationships between the Entiminae fauna of Baltic amber and other Eocene localities are discussed. [ABSTRACT FROM AUTHOR]

Seed germination is a crucial stage in the development of all plants. It normally occurs in the soil after the seed has fallen from the mother plant. In some infrequent instances, precocious germination (a type of viviparity or vivipary) occurs when the seed sprouts while still within the fruit. The present paper describes the first case of precocious germination of a fossil plant involving a number of seeds that have germinated in a pine cone embedded in Eocene Baltic amber. At the tips of the emerging hypocotyls are clusters of needles in fascicles of 5, associating the fossil with the extinct pine species Pinus cembrifolia Caspary described earlier from Baltic amber. Environmental implications of this discovery are discussed. [ABSTRACT FROM AUTHOR]

The Eocene Challis-Kamloops volcanic belt, which runs through the interior of British Columbia and northwest United States for >2, 000 km, developed within a short time interval from ~55 to ~45 Ma. Volcanic rocks of the belt are discontinuously distributed in a series of grabens, half-grabens and calderas. Although predominantly composed of high- to medium-K calc-alkaline rocks that are typical of continental arcs, they were extruded during a time of regional transtensional tectonics in the Cordilleran orogen, which also led to the contemporaneous emplacement of Precambrian metamorphic core complexes near the belt. Their relative contents in Y, Nb, La, Sm, Gd, Yb and Ta suggest that the magmas were formed in relation to slab-failure (slab break-off). Initial Sr and Nd isotopic ratios and neodymium depleted mantle model ages indicate that the northern and southern parts of the belt had isotopically distinct lithospheric mantle sources with, respectively, Palaeozoic to Mesozoic and Precambrian model ages. As all rocks of the belt share common tectonic and petrogenetic settings, greater contents in incompatible trace elements in rocks from the southern part of the belt suggest that the Precambrian sources were more metasomatically enriched in these elements than the Phanerozoic sources. [ABSTRACT FROM AUTHOR]

A new genus and species of middle size bunodont artiodactyl (Mammalia), Erlianhyus primitivus, is established based on a partial maxilla with P3–M3 from the lower middle Eocene Irdin Manha Formation, Erlian Basin, Nei Mongol, China. Erlianhyus is characterised by a low tooth crown, bunodont cusps, a protocone smaller and lower than the paracone on P4, a large metaconule, reduced paraconule, no hypocone and styles on M1–3, and weak crista between the main cones on the upper cheek teeth. Erlianhyus is more similar in dental morphology to the Asian Myanmarius, Myaingtherium and Siamotherium rather than to other artiodactyls. Our cladistics analysis shows that Erlianhyus is positioned outside of the anthracotheriid-suoid-dichobunoid clade and is located more basally within the Artiodactyla, so now it is not referred to any known family or superfamily in artiodactyls. [ABSTRACT FROM AUTHOR]

The Călata site (north-west of Transilvanian Basin, Romania) includes the Ciuleni Member of the middle Eocene-age Mortănușa Formation, a marine deposit in an outer, open marine facies, from where fossil vertebrates were very poorly known. In the last four years, nearly 150 remains of fish (mostly teeth) were recovered from the Călata site. We identified 21 taxa representing 20 genera that belong to 12 orders of chondrichthys and teleostei fishes. This study is the first to report Rostroraja and Palaeocybium from Romania, and we report seven additional genera from the Bartonian of Romania for the first time. We performed analysis of calcareous nannoplankton and foraminifera which allowed us to refine the age of the deposits and corroborate palaeoecological data. The combined data from the microfossils and fishes document the first middle-late Bartonian (NP17) marine fish fauna from Romania. This fauna was deposited in tropical waters with relatively shallow depths and with increased terrigenous input from a probable close-by shoreline. [ABSTRACT FROM AUTHOR]

The family Palaeotheriidae (Perissodactyla, Equoidea) was one of the most abundant and successful Eocene mammalian groups from western Europe. Equoid perissodactyls were diverse in the Iberian Peninsula, with the presence of six genera and 19 species (mainly palaeotheres) which are unknown elsewhere in Europe. In this work, an overview of the Eocene Iberian equoid fossil record is summarised in the context of the European palaeobiogeography, including the updating of the endemic palaeotheriid taxa. The persistence of the endemism in the western Iberian region during the late Eocene could be due to an ecological barrier. There are significant dental pattern differences between the endemic Iberian and the other European palaeotheriid taxa. These differences may be the results of dietary strategies different from those of contemporary European faunas. Some dental features might indicate that the environmental changes driven by the climatic cooling of the latest Eocene in western Europe could have started earlier in western Iberia. [ABSTRACT FROM AUTHOR]

A new nyctitheriid (Indonyctia cambayensis gen. et sp. nov.) is described from an early Eocene (~55 Ma) marginal marine sequence (Cambay Shale) at Vastan Lignite Mine, Gujarat, western India. The new taxon is diagnosed by a unique combination of several characters including a single-rooted p2; a p4 with a tiny paraconid at the base but without a metaconid; weakly developed talonid basin; reduced p3 relative to p2 and p4; molar trigonid wider and much higher than talonid; hypoconulid nearly on midline; entoconid positioned anterolingual to hypoconulid; presence of precingulid and a larger and taller protoconid than metaconid. The Asian affinities of the Indian nyctitheriid are indicated by its structurally reduced, premolariform p4 with a weakly developed unicuspid talonid. In several respects, the Indian nyctitheriid is similar to Voltaia, a late Palaeocene taxon from Kazakhstan originally assigned to the Palaeoryctidae but later classified as a nyctitheriid. The presence of a nyctitheriid in the basal Eocene of India suggests a wider palaeogeographic distribution and complex dispersal of this Holarctic family. The Asian affinities of the Indian nyctitheriid suggest faunal exchanges between India and the Mainland Asia possibly via the Dras-Kohistan island arc around the Palaeocene-Eocene boundary (~56 Ma). [ABSTRACT FROM AUTHOR]

An incomplete fossil record and unstable phylogenies of extinct taxa hamper reconstructing the early evolution of Caimaninae. We describe previously unpublished articulated fossils of a key species, Tsoabichi greenriverensis from the early Eocene Green River Formation of North America, exhibiting further character evidence for the caimanine affinities of this taxon. Parsimony analysis of modified morphological taxon-character datasets coupled with a critical review of character evolution and published phylogenies reveals that fossil evidence for Palaeogene crown group and Late Cretaceous total-group representatives is unreliable due to uncertain character evolution in early Alligatoridae. The earliest unambiguous fossil age for total and crown-group Caimaninae are 63.5 Ma and 18.06 Ma, respectively. These calibration points follow best practices and are vital for better constrained estimates of time calibrated analyses. Phylogeny continues to imply two separate Caimaninae dispersals between North and South America, but instead of a northward back-dispersal, we find two Palaeogene dispersals to South America an equally likely hypothesis. Miocene taxa of Central America previously assigned to the stem lineage ancestral to South American Caimaninae are reinterpreted as part of a Neogene northward expansion of the crown group. [ABSTRACT FROM AUTHOR]

Australian Anglesea amber, late middle Eocene in age, has been recently reported. It occurs in coal deposits formed in a meandering river system on an Austral subpolar coastal plain during a late Greenhouse Earth event, and contains well-preserved bioinclusions of plants, arthropods and microorganisms. Six specimens of biting midges have been recovered and two species are herein described: Meunierohelea anglesensis sp. nov. and Culicoides paleopestis sp. nov. These represent the second and third arthropod species described in Australian amber. The discovery of a new fossil species of the genus Meunierohelea is especially significant, since the only extant species is known from northern Australian tropical rainforests. Additionally, a partial specimen belongs to the Monohelea complex. Interestingly, a male and a female of C. paleopestis sp. nov. occur very close to each other, most likely trapped by the resin during mating, allowing the description of the sexual dimorphism of this species. The species of the genus Culicoides much have fed on the blood of Australian vertebrates during the Eocene, possibly transmitting diseases. These new data extend the knowledge about biting midges during the Eocene, a key time for understanding the global expansion of the Ceratopogonidae into subpolar latitudes. [ABSTRACT FROM AUTHOR]

Among dinoflagellates, extant cladopyxidaceans may provide a missing link to better understand the first evolutionary transformations from ancestral configurations toward the more abundant and more derived patterns in Gonyaulacales and Peridiniales. A restudy of the extant, motile-defined Micracanthodinium setiferum using plankton samples from the Indian and Atlantic oceans and the Mediterranean Sea demonstrates that the correct plate formula is Po, Pt, X, 3′ + *4′, 4a, 7′′, 7C, 4S, ?6′′′, 0p, 2′′′′. A ventral pore is found between 1′, 3′ and *4′. A restudy of the extinct, fossil-defined Cladopyxidium saeptum from the upper Paleocene of Delaware (USA), demonstrated the presence of an identical tabulation. A ventral pore (= porichnion) was positioned between *1′ and 7′′. Cladopyxidium is morphologically closer to Micracanthodinium than to Cladopyxis. Since Cladopyxidium has been extinct since the middle Eocene, it is unlikely that Micracanthodinium and Cladopyxidium have a direct biological link; the close morphological similarity between them does, however, suggest an important phylogenetic relationship between them in the evolution of cladopyxidaceans. [ABSTRACT FROM AUTHOR]

Fragmentary remains, including two anterior premolars, axis fragment, a phalanx, and rib fragments from the Middle Eocene (late Bartonian) Ak-Kaya locality represent the first sirenian fossils from the Paleogene of Crimea. The lower p3 shows some similarity with p3 in the dugongid Eotheroides sp. from the Eocene of North America. The axis is similar in proportions to the axis of the stem sirenian Sobrarbesiren from the Middle Eocene of Spain. The manual(?) phalanx suggests a semiaquatic adaptation of the Crimean sirenian. These remains are identified as Sirenia indet. with possible affinities with the Dugongidae. [ABSTRACT FROM AUTHOR]

Despite belonging to an important time slice in the geological history, the Eocene shallow-marine beds of the Alborz region in Iran have received little attention from researchers. We selected two stratigraphic sections (Mojen and Kalateh) ascribed to the Ziarat Formation as suitable representatives for the current analysis, emphasising on their constituent microfacies and paleoenvironmental implications. The biotic communities are characterised by larger benthic foraminifera (LBF), coralline algae, corals, and bivalves as the major carbonate facies components. The microfacies gradients and paleoenvironmental analysis suggest deposition in a shallow-marine oligotrophic ramp environment within two platform stages. Both these stages indicate an increase in water depth from the inner to the middle ramp settings with spatial distribution of the LBF and other benthic components. Our data support the previous view that the early Eocene witnessed an increase in LBF taxa with near obliteration of the coral reefs in the sedimentary platforms across the Tethys. The corals reinitiated building reefal structures in the Middle Eocene, marking an important phase in the Tethyan paleoenvironmental evolution. [ABSTRACT FROM AUTHOR]

Maomingosuchus acutirostris sp. nov. is a new tomistomine crocodile from the middle–upper Eocene deposits (late Bartonian–Priabonian age, 39–35 Ma) of the Na Duong Basin in northern Vietnam. M. acutirostris can be differentiated from the type species Maomingosuchus petrolicus by having an acute anterior tip of the premaxilla. Both species differ from another Maomingosuchus from Krabi (Thailand) by differences in the surangular–dentary suture and maxillary alveoli. According to our phylogenetic results, M. acutirostris seems to be the sister species to the group M. petrolicus + Krabi-Maomingosuchus. The close relationship between those three tomistomines is supported in the present phylogenetic analysis by three synapomorphies. In our phylogenetic analysis, Maomingosuchus was retrieved in a basal position forming the sister group to Paratomistoma + Gavialosuchus + Melitosaurus + Tomistoma, including the extant Tomistoma schlegelii. This phylogeny indicates three different dispersal events of Tomistominae from Europe towards eastern Asia: 1) for the stem lineage of Maomingosuchus, no later than the late Eocene; 2) for the stem lineage of Penghusuchus pani + Toyotamaphimeia machikanensis, no later than the early–middle Miocene; and (3) for the stem lineage of T. schlegelii, during the Neogene. [ABSTRACT FROM AUTHOR]