Extinct Genus Research Articles

The First Discovery of a Fish Fossil (Phareodus sp.) from Paleogene Fluvial Deposits in Western Washington State, USA

The 2023 discovery of a fish fossil from lower Eocene strata of the Chuckanut Formation provides new insights into the paleoenvironment and paleoecology of one of the region’s most prolific fossil deposits. The detrital clastic fluvial and floodplain deposits of the Chuckanut Formation are not favorable for the preservation of fish, but the high quality of preservation of this specimen is evidence that some Chuckanut Formation sediments provide suitable depositional conditions for the preservation of skeletal remains. This information improves our understanding of the range of depositional environments within the Chuckanut Formation, and provides clues for searching for additional specimens. The discovery of this fossil has larger significance; the skeletal remains of fish are scarce in fluvial and floodplain deposits. Despite its incompleteness, dorsal fin and caudal fin ray anatomy suggest that the specimens represent the extinct genus Phareodus, an open-water carnivore that has previously only been reported in North America from the Green River and Bridger Formations in Wyoming and Utah, USA.

Ancient DNA re-opens the question of the phylogenetic position of the Sardinian pika Prolagus sardus (Wagner, 1829), an extinct lagomorph

Palaeogenomics is contributing to refine our understanding of many major evolutionary events at an unprecedented resolution, with relevant impacts in several fields, including phylogenetics of extinct species. Few extant and extinct animal species from Mediterranean regions have been characterised at the DNA level thus far. The Sardinian pika, Prolagus sardus (Wagner, 1829), was an iconic lagomorph species that populated Sardinia and Corsica and became extinct during the Holocene. There is a certain scientific debate on the phylogenetic assignment of the extinct genus Prolagus to the family Ochotonidae (one of the only two extant families of the order Lagomorpha) or to a separated family Prolagidae, or to the subfamily Prolaginae within the family Ochotonidae. In this study, we successfully reconstructed a portion of the mitogenome of a Sardinian pika dated to the Neolithic period and recovered from the Cabaddaris cave, an archaeological site in Sardinia. Our calibrated phylogeny may support the hypothesis that the genus Prolagus is an independent sister group to the family Ochotonidae that diverged from the Ochotona genus lineage about 30 million years ago. These results may contribute to refine the phylogenetic interpretation of the morphological peculiarities of the Prolagus genus already described by palaeontological studies.

Ursidae (Mammalia, Carnivora) from the Quaternary of western Rio Grande do Sul, Brazil: Taxonomical, stratigraphic, and chronological aspects

All known Pleistocene South American fossil ursids belong to Arctotherium, an extinct genus of tremarctine bears. Its occurrence encompasses many countries in Central and South America, with findings mainly from Argentina. In Brazil, the genus is recorded in eight states, highlighting Rio Grande do Sul due to its provenance from fluvial deposits. In contrast, all other Brazilian records come from caves or fossil tanks. The Arctotherium material from Rio Grande do Sul comes from the Passo do Juquiry site, located on the banks of the Quaraí River, which marks the frontier between Brazil and Uruguay. The fossils are MCN-PV 1940/A-K, a set of postcranial bones: first to sixth lumbar vertebrae, sacrum, left scapula, left humerus, right portion of the pelvic girdle, and left femur. The anatomic description of these bones confirmed their belonging to Arctotherium sp. due to their size, the form of the vertebral processes, the presence of the entepicondylar foramen of the humerus, and the morphology of the trochlea and capitulum. Body mass estimates resulted in values mostly above 400 kg. The first absolute age from Passo do Juquiry indicated 40,000 years BP. The stratigraphic framework of the outcrop conformed to a floodplain fines facies association, a succession of mudstones with carbonate nodules on top. This facies association has lithological correlations to the Brazilian Touro Passo Formation, the Uruguayan Sopas Formation, and the Argentinean Toropí/Yupoí Formation. While having similar features, the ages of the lithologically correlated facies associations do not always line up, indicating that the evolution of the Uruguay River basin throughout the Late Pleistocene followed a pattern, but not synchronously. The presence of carbonate levels suggests that the climate during the time of deposition was drier than the present one, with the carbonate-less middle layer representing a more humid period.

A new species of Cerylonidae (Insecta: Coleoptera) described from Baltic amber using X-Ray microtomography

ABSTRACT 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

A new peltoperlid stonefly from mid-Cretaceous amber of northern Myanmar (Plecoptera: Peltoperlidae)

The eggs of insects are evolving diversely under developmental, morphological, and ecological pressures. Fossil eggs of insects can provide essential biological and evolutionary implications for the related insect groups. Peltoperlidae is a small stonefly family comprising 10 extant genera in two extant subfamilies and only two extinct genera in a fossil subfamily. The phylogenetic relationship between the three subfamilies of Peltoperlidae as well as the generic level phylogeny remain unclear. Herein, a new Cretaceous peltoperlid genus and species, Dewaltoperla edwardi gen. et sp. nov., is reported in Kachin amber from northern Myanmar (98.79 ± 0.62 Ma). The discovery presents the third fossil stonefly of Peltoperlidae, and more importantly, the first fossil eggs for the family. Dewaltoperla is assigned to the extinct subfamily Borisoperlinae and can be distinguished from other fossil peltoperlids by wing venation. The morphological phylogenetic analysis was conducted for all peltoperlid genera for the first time, which identifies Borisoperlinae as a basal group within Peltoperlidae and suggests an evolutionary trend of the egg shape transition from flattened to spherical ones.

Fossil micromammals and the palaeoenvironments of the Paranthropus robustus site of Cooper’s Cave

ABSTRACT The Cradle of Humankind (Gauteng, South Africa) provides an important fossil record of the evolutionary history of PlioPleistocene hominins. Cooper’s Cave deposits have yielded a rich fossil faunal assemblage, as well as six remains attributed to Paranthropus robustus. This study provides the first taxonomic, taphonomic and palaeoecological description of the micromammal material from the 1.4 Ma assemblage of Cooper’s D. The taphonomic signature of the assemblage indicates an accumulation by tytonid owls (probably Tyto alba) and advanced postdepositional disturbance probably related to trampling by the occupants of the cave, sorting of the bones along slope, and burying. The taxonomic analysis undertaken here at genus level describes at least 22 taxa of small mammals, including one extinct genus Proodontomys. This assemblage is dominated by Mystromys and Otomys, two rodent genera adapted to grassland habitats which are among the most common among pliopleistocene micromammal faunas from the region. The palaeoecological analysis suggests an open landscape with a predominance of grassland and savanna vegetation, and the proximity of rocky outcrops and a perennial river. These results support previous indications of a shift in the African climate and vegetation towards more open habitats during the Early Pleistocene.

A New Extinct Ant Genus (Hymenoptera: Formicidae) from Baltic Amber

A new extinct genus and species from the subfamily Dolichoderinae, Dlusskyus groehni gen. et sp. nov., is described based on the single male from Baltic amber (late Eocene, 37.8–33.9 Ma). It differs from all extant and extinct Dolichoderinae genera in the following combination of features: antennae 13-segmented, scape shorter than the second funicular segment, which is the longest; palp formula 6, 4; clypeus not inserted between frontal carinae, frontal triangle well outlined and separated from clypeus by suture; clypeus with longitudinal median carina, its anterior margin very weakly convex, without medial notch; mandibles crossing when closed, masticatory margin long, with two minute sharp apical and preapical teeth and a row of minute sharp denticles, serrate; scutum without notauli; petiole nodiform, with short peduncle; meso- and metatibiae with large simple spur; pretarsal claws without preapical tooth; posterior margin of pygidium with median tooth; subgenital plate with very shallow median notch; pygostiles present; stipites of genitalia very weakly curved, narrow, with rounded apices, telomeres not strongly elongated; forewings with closed cells 1r+2r, 3r, rm and mcu; jugal lobe absent. The taxonomic position of this genus is discussed.

Kupakara gen. nov., a new genus of Blediini in mid-Cretaceous amber from northern Myanmar (Coleoptera: Staphylinidae: Oxytelinae)

A new genus and two new species are described and figured based on well-preserved individuals in the mid-Cretaceous amber from northern Myanmar. The staphylinids are placed in a new extinct genus, Kupakara gen. nov., with two species Kupakara makranczyi sp. nov. and Kupakara luminosus sp. nov.. They are tentatively placed in the extant tribe Blediini Ádám of the subfamily Oxytelinae Fleming based on abdominal segments III to VI with two pairs of laterosclerites per segment, abdominal sternite II well-developed and articulated to sternite III by a long connecting membrane, eyes not extending onto ventral portion of head, antenna geniculate with first article elongate and last three antennomeres dilated to form a well-defined but loose club, body dark brown with yellowish brown elytra, procoxal fissure present with exposed protrochantin, and tibiae spinous. Kupakara is separated from other allied genera by the gular sutures slightly confluent at the anterior margin and divergent to the basal portion, pronotal lateral margins sinuate in the posterior half, and a distinct neck.

On the systematic position of Cretothereva (Diptera, Therevidae): criticism versus evidence

ABSTRACT An extinct genus and species of Diptera – Cretothereva antiqua – has recently been described from the Lower Cretaceous of Brazil (Crato Formation). The fossil has been assigned to the family Therevidae and, according to its authors, would represent the oldest known member of the family of the entire Therevoid clade, with important implications for the evolutionary history of the group. A recent paper written by several Diptera experts challenges the systematic position of Cretothereva antiqua, but without a detailed assessment of the evidences. The evidence for the systematic position of this important fossil is reassessed. We argue that criticism of scientific hypotheses must be based on formal discussion of evidence, not based only on conjecture.

The second European representative of the epallagid genus Labandeiraia in the lowermost Eocene Oise amber (Odonata, Zygoptera)

Among the calopteran damselflies, the family Epallagidae was clearly dominating the diversity of the Holarctic Cenozoic (11 described species in eight extinct genera), while the Calopterygidae were extremely rare at the same time (six Cenozoic species in two extant and one fossil genera) (Fossilworks database at http://www.fossilworks.org/cgi-bin/bridge.pl?action=home, consulted 21/10/2022). They mainly belonged to the extinct subfamily Eodichrominae Cockerell, 1923, and their most diverse genus was the early Eocene genus Labandeiraia Petrulevičius et al., 2007, known from compression fossils from the lacustrine Green River Formation (USA) and the marine Fur Formation in Denmark (Petrulevičius et al., 2007; Bechly et al., 2020).

Tooth chipping patterns in Archaeolemur provide insight into diet and behavior.

Archaeolemur is a recently extinct genus of lemur that is often compared to some Cercopithecidae, especially baboons. This is due in part to their derived dentition, with large anterior teeth and reduced bilophodont molars. Research involving comparative morphology, analysis of coprolites, isotopes, and enamel structure, have suggested Archaeolemur had an omnivorous diet involving mechanically challenging items. Yet, microwear analysis of posterior teeth does not necessarily support this conclusion. In this macroscopic study, dental chipping was recorded on permanent teeth of Archaeolemur from different localities (53 individuals; 447 permanent teeth; including both A. edwardsi and A. majori specimens). This study aimed to compare chipping patterns across the dentition of Archaeolemur with chipping in other primates. The results show enamel chipping was prevalent on the anterior teeth of Archaeolemur (38.9% of anterior teeth showed at least one fracture) yet rare in posterior teeth (9%). There was a decrease in chipping frequency across the dentition, moving distally from incisors (50%; 20/40), through caniniform teeth (30%; 15/50), premolars (9.5%; 16/169), and molars (8.5%; 16/188). The results support previous research suggesting Archaeolemur had a varied omnivorous diet in which the anterior dentition was used for extensive food processing. This likely included mechanically challenging items such as tough/hard large fruits, small vertebrates, and crustaceans. Such a high rate of chipping in the anterior dentition is uncommon in other primates, with exception of hominins.

Phylogeny and systematics of Sphaeriusidae (Coleoptera: Myxophaga): minute living fossils with underestimated past and present‐day diversity

AbstractSphaeriusidae (Coleoptera: Myxophaga) is a group of shiny, blackish and hemispherical riparian beetles, known for their miniaturized bodies. They are worldwide in distribution, but very limited information is available about taxonomic and morphological diversity, and natural and evolutionary history. The aim of this study is to help fill in these gaps. We examined the external morphology of modern representatives using scanning electron microscopy (SEM), and reconstructed the phylogeny of the family using five DNA markers (cytochrome oxidase I, 18S rRNA, 28S rRNA, CAD and wingless). Our results suggest a larger morphological diversity than previously expected, corresponding to the deep genetic divergences of principal lineages. We also examined two inclusions in 99‐million‐year‐old Burmese amber. The integration of all evidence allows us to recognize three genera: the extinct genus †Burmasporum Kirejtshuk, the newly defined genus Bezesporum gen.nov. preserved in Burmese amber (B. burmiticum sp.nov.) and present in the modern fauna of Southeast Asia, and the genus Sphaerius Waltl with a world‐wide distribution. Sphaerius species are morphologically highly uniform, with the exception of species from Australia and South Africa, which share some characteristics with Bezesporum gen.nov. despite being resolved as deeply nested lineages of Sphaerius by DNA data. The presence of Bezesporum gen.nov. in Burmese amber and in recent fauna indicates that Sphaeriusidae largely maintained their specific morphology and specialized riparian lifestyle for at least 100 million years. Therefore, they can be considered an exceptionally conserved group, with a minimum of evolutionary changes over a long period. Our study also demonstrates that the species numbers and fine‐scale morphological diversity of Sphaeriusidae are larger than expected in both the past and present‐day faunas. Both were apparently underestimated due to the minute body size and cryptic habits of these beetles.

Hemitrapa Miki (Lythraceae) from the middle Miocene tropical lowland rainforest of southern China

Hemitrapa is an extinct genus in the subfamily Trapoideae with rich fossil records in Eurasia and North America. However, the diversification history of Hemitrapa is poorly known in southern China. Here, we describe a new species of the subfamily Trapoideae (Lythraceae), Hemitrapa zhangpuensis n. sp., based on well-preserved fossil fruits from the middle Miocene Zhangpu flora of Fujian, southern China. The new fossils contribute to understanding the history of plant diversity in southern China and the ontogeny of the fruit. In addition, this finding represents the southernmost fossil record of the genus worldwide, which greatly expands the spatial distribution and ecological habitat of Hemitrapa during the middle Miocene.

A remarkable new fossil species of Amplectister with peculiar hindleg modifications (Coleoptera: Histeridae): further evidence for myrmecophily in Cretaceous clown beetles

Myrmecophily is a phenomenon of the symbiosis of organisms that depend on various ant (Formicidae) societies. Such interspecies associations are found in several unrelated lineages within the clown beetle family Histeridae. Recent studies have suggested that the origin of myrmecophily can be traced back to mid-Cretaceous based on a few fossil records from Kachin amber from northern Myanmar. Here, we describe a remarkable new species, Amplectister terapoides n. sp., from Kachin amber. This is the second species of the extinct genus Amplectister Caterino and Maddison, which has been found from the same amber deposit and has also been considered to be myrmecophilous. The new species here described has the most heavily modified hindlegs in any fossil histerids or even beetles discovered until now, indicating further evidence for ant colony association. Our discovery demonstrates that significant and diverse morphological adaptations to myrmecophily had already occurred during the Cretaceous.

Morphology-based Phylogenetic Analysis of Membracoidea (Hemiptera: Cicadomorpha) With Placement of Fossil Taxa and Description of a New Subfamily

Abstract Recently discovered amber-preserved fossil Cicadellidae exhibit combinations of morphological traits not observed in the modern fauna and have the potential to shed new light on the evolution of this highly diverse family. To place the fossils explicitly within a phylogenetic context, representatives of five extinct genera from Cretaceous Myanmar amber, and one from Eocene Baltic amber were incorporated into a matrix comprising 229 discrete morphological characters and representatives of all modern subfamilies. Phylogenetic analyses yielded well resolved and largely congruent estimates that support the monophyly of most previously recognized cicadellid subfamilies and indicate that the treehoppers are derived from a lineage of Cicadellidae. Instability in the morphology-based phylogenies is mainly confined to deep internal splits that received low branch support in one or more analyses and also were not consistently resolved by recent phylogenomic analyses. Placement of fossil taxa is mostly stable across analyses. Three new Cretaceous leafhopper genera, Burmotettix gen. nov., Kachinella gen nov., and Viraktamathus gen. nov., consistently form a monophyletic group distinct from extant leafhopper subfamilies and are placed in Burmotettiginae subfam. nov. Extinct Cretaceous fossils previously placed in Ledrinae and Signoretiinae are recovered as sister to modern representatives of these groups. Eomegophthalmus Dietrich and Gonçalves from Baltic amber consistently groups with a lineage comprising treehoppers, Megophthalminae, Ulopinae, and Eurymelinae but its position is unstable. Overall, the morphology-based phylogenetic estimates agree with recent phylogenies based on molecular data alone suggesting that morphological traits recently used to diagnose subfamilies are generally informative of phylogenetic relationships within this group.

Podocarpium (Fabaceae) from the late Eocene of central Tibetan Plateau and its biogeographic implication

Podocarpium is an extinct genus in Fabaceae with rich fossil records in Eurasia dating back to the Eocene. However, the diversification and biogeographic histories of Podocarpium are poorly known due to a lack of fossils in some key regions, such as the Tibetan Plateau, an area recently shown to be crucial for floristic exchanges worldwide in the geological past. Here, we describe well-preserved fossil pods of Podocarpium from the late Eocene (~35 Ma) of the Lunpola Basin, central Tibetan Plateau, China. Together with detailed morphological observation and geometric morphology analysis, these fossil pods are named Podocarpium tibeticum W.-C. Li, J. Huang et T. Su sp. nov., characterized by asymmetrical elliptical valves, olecranon fruit beak, and a clearly oblique base. This material comprises the oldest fossil record of Podocarpium from the Tibetan Plateau and adjacent regions. The discovery of P. tibeticum shows Podocarpium was present in central Tibet by the late Eocene. Together with previous fossil records, it indicates that Podocarpium may have originated in East Asia, migrated into the central valley of Tibet in the late Eocene, and then spread westward to Europe through a low-latitude path of island chains along the Neotethys. Results of paleoecological niche modeling demonstrate that Podocarpium had an almost worldwide potential distribution range in the Eocene, but this sharply contracted thereafter until by the Pliocene it was restricted to a small area of East Asia. Generally, this finding further supports the idea that what is now the central Tibetan Plateau was a globally significant hub for Paleogene floristic exchange.

Revision of the oldest varanid, Saniwa orsmaelensis Dollo, 1923, from the earliest Eocene of northwest Europe

Saniwa is an extinct genus of varanid squamate from the Eocene of North America and Europe. Up to now, only one poorly known species, Saniwa orsmaelensis Dollo, 1923, has been reported from Europe. Diagnostic material was limited to vertebrae with only preliminary description and no figure provided, except of one dorsal vertebra that was designated as the lectotype. New specimens from the earliest Eocene of Dormaal, Belgium and Le Quesnoy, France, including recently recovered skull material, are described and illustrated here. These fossils representing the oldest varanid squamate allow further comparisons with the type species, Saniwa ensidens Leidy, 1870, from the early and middle Eocene of North America and to propose a new diagnosis for S. orsmaelensis. Its arrival in Europe is probably linked to rapid environmental changes around the Paleocene Eocene Thermal Maximum (PETM). The occurrence of S. orsmaelensis is restricted to the early Eocene of northwest Europe and paleogeographic considerations regarding the distribution of the genus Saniwa Leidy, 1870 suggest an Asian origin, but an African origin cannot be completely excluded.

First Member of 'Higher Endomychidae' (Coleoptera: Coccinelloidea) from the Mid-Cretaceous Amber of Myanmar and New Insights into the Time of Origin of the Handsome Fungus Beetles.

Simple SummaryWe discovered an extinct handsome fungus beetle almost 100 million years old embedded in amber from Myanmar. Comparing and analyzing the characteristics of its body with those of other beetles of this family living today, we were able to find out which ones could be their closest relatives. What we discovered suggests that our beetle, representing a new genus and species, is a part of a group called “Higher Endomychidae”. This group shares some features with members of the family Coccinellidae, the well-known ladybugs or ladybirds. Our finding supports the hypothesis that handsome fungus beetles (family Endomychidae) originated at least at the beginning of the Cretaceous period, and most probably in the Jurassic, coinciding with the heyday of dinosaurs on earth.A new genus and species of the family Endomychidae (Coleoptera: Coccinelloidea): Cretostenotarsus striatus Tomaszewska, Szawaryn and Arriaga-Varela gen. et sp. nov. are described, diagnosed and illustrated from the mid-Cretaceous amber from northern Myanmar. To test the systematic placement of the new extinct genus and species within the family, a phylogenetic analysis was conducted. A dataset of 38 morphological characters scored for 29 species (including the new fossil taxon), members of Endomychidae sensu stricto and representatives of Coccinelloidea as outgroups were analyzed using maximum parsimony. The results of the analysis indicate unequivocally that Cretostenotarsus striatus is a member of the Stenotarsus clade within a monophyletic ‘endomychine complex’ sensu Robertson et al. (2015), which corresponds to ‘Higher Endomychidae’ sensu Tomaszewska (2005). The present discovery confirms at least the Jurassic origin of Coccinelloidea and indicates a much older origin of Endomychidae than previously hypothesized.

Revision of Archizelmira Rohdendorf, 1962 (Diptera, Archizelmiridae)

A new species of the extinct genus Archizelmira Rohdendorf, 1962 is described based on an isolated wing from the Middle Jurassic of West Siberia (Itat Formation, Bathonian). Both previously known species are re-examined. Additional wing venation characters are found for the genus, which support its status as a sister group to the rest of the family. A new Cretaceous subfamily, Burmazelmirinae subfam. nov. is proposed.

Cretaceous Antodicranomyia (Diptera: Limoniidae) and their paleohabitat

New representatives of the Cretaceous cranefly genus Antodicranomyia (Diptera: Limoniidae) are reported from Albian-Cenomanian Charentese (French) amber. The newly reported specimens allow for an emended diagnosis of the type species A. azari, as well as the description of a new species, Antodicranomyia rubra sp. nov., which is mostly distinguished from the type species by features of its wing venation, antennae, and genitalia. As a rare, extinct genus known only from French amber, Antodicranomyia is compared with its closest relative genera Antocha, Dicranomyia and Antohelia. The evolutionary implications and paleohabitat of Antodicranomyia are discussed. The new discovery adds to the knowledge of the crane flies’ diversity and evolution in the mid-Cretaceous.