The first fossil Typhlocybinae inclusions from Eocene Rovno amber are described and illustrated. They include two new monotypic genera of the extinct tribe Protodikraneurini, Retrorsotettix n. gen. with type species R. vlaskini n. sp. and Protoparallaxis n. gen. with type species P. clavatus n. sp. Also described and illustrated are two new monotypic genera of the extant tribe Dikraneurini, Eodikraneura n. gen. with type species E. obscura n. sp. and Rovnodikra n. gen. with type species Rovnodikra longipes n. sp. Retrorsotettix is the oldest leafhopper known to exhibit a false eyespot and false leg markings on the forewing, representing an early acquisition of a defensive strategy against visual predators. Appearance of a small insect with false eyespots in the Eocene fossil record may reflect increased pressure by visual predators, especially crown ornithuromorph insectivorous birds. Such birds and small insect prey with false eyespots remain unknown in the Cretaceous. Eodikraneura exhibits a unique condition of the hind wing venation in which radius posterior and media anterior veins are confluent for a short distance but then diverge before separately reaching the submarginal vein. This presumably represents a morphological transition between the Protodikraneurini, in which hind-wing radius posterior and media anterior veins are completely separate and connected by a radial-medial crossvein, and Dikraneurini, in which radius posterior and media anterior veins are completely confluent distally. A key to genera of Protodikraneurini is provided.

UUID: http://zoobank.org/f15e6f80-9708-4f5e-89a3-705f9d340a77

Numerous species of “oliviform” gastropods have been recognized in the Paleogene of the U.S. Gulf Coastal Plain, many of which have previously been allied to the “Bullia group” in the family Nassariidae, and placed in a variety of poorly defined genera. We review these species, revise their generic and familial placement, and present a phylogenetic analysis. Of 19 species considered valid, all are assigned to Olivoidea, six to Olividae—one to Oliva, five to Agaronia—and the rest to Ancillariidae. The highly variable species Ancillaria altile Conrad is referred in the genus Ancillopsis and appears to have evolved anagenetically over an interval of perhaps 20 million years. Ancillaria tenera Conrad and Ancillaria scamba Conrad are placed in the new genus Palmoliva. Monoptygma Lea is demonstrated to belong to Ancillariidae, and to contain only a single species. Specimens assigned to Lisbonia expansa Palmer are split into adults assigned to Ancillopsis altilis and juveniles (together with several other species) in the long-lived species Anbullina elliptica (Whitfield). Coastal Plain ancillariids may have evolved from one or more species of the Cretaceous–Paleocene genus Eoancilla. We agree with previous authors who have suggested that the late Eocene species Oliva mississippiensis Conrad is the earliest known representative of this genus and the subfamily Oliviinae, perhaps derived from a species of Agaronia. The oldest Agaronia is lower Eocene (Ypresian).

UUID: http://zoobank.org/b7d9f79b-c68b-4385-aba3-bb07c6d6dc87

Proterozoic eukaryotic macroalgae are difficult to interpret because morphological details required for proper phylogenetic studies are rarely preserved. This is especially true of morphologically simple organisms consisting of tubes, ribbons, or spheres that are commonly found in a wide array of bacteria, plants, and even animals. Previous reports of exceptionally preserved Tonian (ca. 950−900 Ma) fossils from the Dolores Creek Formation of Northwestern Canada feature enough morphological evidence to support a green macroalgal affinity. However, the affinities of two additional forms identified on the basis of the size distribution of available specimens remain undetermined, while the presence of three unique algal forms supports other reports of increasing algal diversity in the early Neoproterozoic. Archaeochaeta guncho new genus new species is described as a green macroalga on the basis of its well-preserved morphology consisting of an unbranching, uniseriate thallus with uniform width throughout and possessing an elliptical to globose anchoring holdfast. A larger size class of ribbon-like forms is interpreted as Vendotaenia sp. A third size class is significantly smaller than Archaeochaeta n. gen. and Vendotaenia, but in the absence of clear morphological characters, it remains difficult to assign. As Archaeochaeta n. gen. and Vendotaenia represent photoautotrophic taxa, these findings support the hypothesis of increasing morphological complexity and phyletic diversification of macroalgae during the Tonian, leading to dramatic changes within benthic marine ecosystems before the evolution of animals.

How will freshwater lakes in the Arctic respond to climate change, especially if polar amplification results in even greater warming at these northern latitudes? Deep time analogs offer opportunities to understand the potential effects of future climate warming on arctic environments. A core from the Giraffe Pipe fossil locality located in the Northwest Territories of Canada offers a window into the life of a thriving Arctic freshwater ecosystem in the Eocene during greenhouse conditions. The remains of an extensive deposit of microfossils, including photosynthetic protists (chrysophytes, diatoms, and green algae), heterotrophic protists (euglyphids, heliozoans, paraphysomonads, and rotosphaerids), and sponges, were used to reconstruct the history of the ancient waterbody. Concentrations and diversity of chrysophyte taxa were extensive throughout the core, accounting for >70% of the microfossil remains. The ratio of chrysophyte cysts to diatom valves, with a mean value near 14 throughout the core, further emphasized the dominance of the chrysophytes, and given the high diversity of taxa, the locality represents a “paleo-hotspot” for this eukaryote lineage. Based on the totality of fossil evidence, the waterbody within the Giraffe Pipe crater represented a series of relatively shallow aquatic habitats, with changing physical and chemical conditions, and varying water depths. Five major zones were identified, each found to be stable for an extended period of time, but with distinct transitions between successive zones signaling significant shifts in environmental conditions. The study provides valuable insight on how Arctic freshwater ecosystems responded to past warm climates, and to the organisms that could potentially thrive in these environments under future warming scenarios.

This study provides the first focused investigation of rudist bivalves from the Upper Cretaceous of the Gulf Coastal Plain (GCP) in the southern US and previously undescribed specimens from the Flor de Alba Limestone Member of the Pozas Formation in Puerto Rico. Identified rudists from the GCP comprise the Monopleuridae, including Gyropleura, as well as Radiolitidae, including Biradiolites cardenasensi, Durania maxima, Guanacastea jamaicensis, Radiolites acutocostata, and Sauvagesia. Integrating rudist occurrences within well-established GCP biostratigraphy allows for extension of upper ranges of D. maxima and R. acutocostata into the late Campanian, and extension of the lower ranges of B. cardenasensis and G. jamaicensis into the early Campanian. Identified rudists from Puerto Rico comprise the Hippuritidae and include Barrettia monilifera, which supports the age of the Flor de Alba Limestone Member of the Pozas Formation as middle Campanian. Combined taxonomic, biostratigraphic, and paleobiogeographic analyses indicate there is no rudist fauna endemic to the GCP, and the region marks the northeastern range of the Caribbean genera Biradiolites, Durania, Guanacastea, Gyropleura, Radiolites, and Sauvagesia during the Campanian and Maastrichtian. The new occurrences help inform future updates of Late Cretaceous sea surface-current reconstructions for the Caribbean and Western Interior Seaway, USA.

Paromomyidae are one of several families of plesiadapiforms that flourished during the Paleocene in North America soon after the extinction of non-avian dinosaurs some 66 million years ago. Although they are often among the best-represented plesiadapiforms in mammalian faunas in both North America and Europe, the early history of paromomyids is poorly understood, and their fossil record at higher latitudes is comparatively depauperate. We report here on the discovery of two new species of paromomyids from Paleocene deposits in southwestern Alberta: Edworthia greggi new species is the second known species of the basal paromomyid Edworthia Fox, Scott, and Rankin, 2010 whereas Ignacius glenbowensis new species is among the most abundantly represented species of Ignacius Matthew and Granger, 1921. These new discoveries document, for the first time, parts of the upper dentition of Edworthia, and the new species of Ignacius represents the first new, pre-Clarkforkian species of the genus to be described in nearly 100 years. A comprehensive phylogenetic analysis of nearly all known paromomyid taxa (including the new species described herein) recovered both species of Edworthia near the base of the paromomyid tree in a polytomy with Paromomys depressidens Gidley, 1923 and a paraphyletic Ignacius. The new paromomyids from Alberta not only increase the known taxonomic diversity of Edworthia and Ignacius but also add significantly to knowledge of the dental anatomy of these poorly known genera and further add to a uniquely Canadian complement of Paleocene plesiadapiforms.

UUID: http://zoobank.org/a2f31cfe-09b9-4168-b09f-9d0c3d0af342

The morphology of Zygospira, an early atrypide brachiopod, was analyzed using a multivariate approach. Principal component analysis and discriminant analysis clearly differentiated species as they are currently defined primarily based on differences in shell size and ornamentation but not in terms of overall shell shape. The older Zygospira modesta was able to persist into the late Katian (Richmondian) while smaller early species in other brachiopod lineages mostly went extinct. This may have been possible through niche partitioning because the smaller shells have been found attached to other filter feeders and no larger species have been found in these associations so far. This could represent a rare example of sympatric speciation preserved in the fossil record. In the future, detailed study of the spiralia and their associated structures may provide clues as to the ultimate evolutionary affinities of this group in relation to the other atrypide brachiopods evolving at this time.

A diverse molluscan assemblage dominated by turritellid gastropods found in Kachchh, western India, has been interpreted in the past as Late Jurassic (Oxfordian) in age, based on associated undoubtedly Oxfordian ammonites. Recently, several investigations focused on the assemblage dealing with taxonomic, paleoecological, and evolutionary aspects. An analysis of the associated bivalve fauna, foraminiferal assemblage, and the geological context strongly suggests a Miocene rather than a Jurassic age and invalidates several conclusions drawn from the alleged Jurassic age of the fossils.

Seven species of cornulitids, one unidentified tubicolous shell, and the problematic bryozoan Lagenosypho Spandel, 1898 are here described from the Katian of Baltica. Three new species—Cornulites lindae new species, Cornulites meidlai new species, and Conchicolites kroegeri new species—are described. The unidentified tubicolous organism has punctate shell structure and setae-like structures that can best be affiliated with lophophorates. The Hirmuse fauna indicates that the diversity and number of cornulitids in the Ordovician of Baltica has been underestimated and it is likely that the Baltic cornulitid fauna was as diverse and abundant as the fauna of Laurentia. Clay mud-bottom environments supported the highest cornulitid diversity in the Late Ordovician of Baltica. The occurrence of intermediate forms indicates that some tentaculitid characters, e.g., regular annulation and a nearly straight shell, which were thought to be apomorphies of free-living tentaculitids, were actually inherited from ancestral cornulitids. The cornulitid fauna of the Late Ordovician of Laurentia somewhat resembles the cornulitid fauna of the Late Ordovician of Baltica, but there are fewer common faunal elements between Gondwana and Baltica.

UUID: http://zoobank.org/cc704237-b578-4d06-a8ed-8457ca3ce972

We report new, fossiliferous Paleogene Naran Bulak Formation localities from the central-eastern part of the Nemegt Basin of the Gobi Desert, Mongolia. Early Paleogene localities have been identified previously only in the western half of the Nemegt Basin. The new localities, near the town of Daus, are also noteworthy for their geographical proximity to Ukhaa Tolgod, a Late Cretaceous Djadokhta Formation locality known for its numerous dinosaur, mammal, and lizard fossils. The Daus section consists of the Zhigden, Naran, and Bumban members of the Naran Bulak Formation at three localities, and mammal and ostracode fossils were discovered in the Naran Member. Noteworthy discoveries are a dentary of the pantodont Archaeolambda cf. A. planicanina, postcrania of Pantolambdodon, a skull of the gliroid Gomphos, and a partial skull with a worn and damaged dentition provisionally identified as an arctostylopid. Biostratigraphy has been the primary means of dating Paleogene Asian faunas, however, the local fauna from the new localities does not fit easily with established patterns. The Naran Member and Archaeolambda planicanina and the arctostylopid Palaeostylops typically have been allied with the Gashatan Asian Land Mammal Age (ALMA) and attributed to the latest Paleocene. By contrast, Gomphos repeatedly has been found in the Bumban Member and assigned a Bumbanian ALMA, which has been considered as the earliest Eocene. Pantolambdodon has been reported from middle Eocene Arshatan and Irdinmanhan ALMA beds. The co-occurrence of these taxa in Naran Member beds complicates the temporal interpretation of the new localities and the reliability of broader biostratigraphic patterns.

Zygocycloides? foerstei n. sp. is described from the Llandovery (Aeronian) Brassfield Formation of southwestern Ohio. This is among the oldest reported Silurian cyclocystoids from North America and is the only North American Llandovery cyclocystoid that is preserved with a complete rim of marginal ossicles. Zygocycloides Smith and Paul, 1982 is most similar to Nicholsodiscus Glass et al., 2003 (Katian) and Perforocycloides Ewin et al., 2019 (Llandovery, Telychian), both from Anticosti Island, Québec. Cyclocystoids (Ordovician to Mississippian) survived Late Ordovician extinctions, and this discovery documents that this echinoderm clade was part of shallow-water, marine paleocommunities during the initial post-extinction transgression onto the Laurentian platform.

UUID: http://zoobank.org/3d3e092e-267b-4841-9245-6275d1eb79a1

Ray-finned fishes comprise nearly half of extant vertebrate species and include several ancient lineages with fossil records that stretch over 200 Myr in time. One of these old clades, the sturgeons and paddlefishes, is distributed across the Northern Hemisphere and includes some of the largest known freshwater fishes. Yet, the fossil record of this lineage (Acipenseriformes) is poor compared to similarly ancient ray-finned fish clades. Here, I describe sturgeon fossils from two geological units in North America < 10 Myr younger than the Cretaceous-Paleogene boundary. Both come from individuals of ~1.5 m in length. These Paleogene forms establish the long history of large body size in Acipenseriforms and reveal sturgeons were some of the largest inhabitants of freshwater ecosystems that were still recovering from the Cretaceous-Paleogene extinction.

A new hibbertopterid eurypterid, Cyrtoctenus bambachi n. sp., is described from the Early Mississippian (Tournaisian) Price Formation of western Virginia. The same unit yields an unidentifiable stylonurine eurypterid. These are the first eurypterids documented from the Mississippian of North America, and only the fourth locality of this age anywhere in the world to yield eurypterids.

UUID: http://zoobank.org/5c84d3a2-ea5a-402c-970d-9b0d867f52c7

Anticosti Island, eastern Canada, records an exceptionally thick and well-exposed Ordovician/Silurian boundary section that hosts a series of diverse marine invertebrate faunas across the Late Ordovician mass extinction. However, the base of the terminal Ordovician stage, the Hirnantian, has been difficult to identify on Anticosti due to the lack of a traditional Hirnantia fauna within the Upper Ordovician Ellis Bay Formation. Previously, the eponymous taxon of the Hirnantia fauna, and type species of the genus Hirnantia, H. sagittifera (M'Coy, 1851) has been reported only from the uppermost Ellis Bay Formation, leading to uncertainty as to the age of the lower Ellis Bay Formation. Here we report Hirnantia notiskuani n. sp. from the lowermost Ellis Bay Formation. This new species is similar to the type species, H. sagittifera, but is distinguished by its strongly dorsibiconvex shell in mature forms and variously developed uniplicate anterior commissure. Occurrences of these two similar species of Hirnantia, H. notiskuani and H. sagittifera, within the lower and uppermost Ellis Bay Formation, respectively, indicate a Hirnantian age for the entire Ellis Bay Formation, a finding that is supported by recent palynological and chemostratigraphic studies. Brachiopod assemblages within the Ellis Bay Formation therefore are best characterized as a unique and diverse Hirnantia fauna, consisting of genera from both the typical Hirnantia fauna and the epeiric seas of Laurentia.

UUID: http://zoobank.org/1c1dff6a-ee38-4cd3-b8bd-3d803a2774ef

Although the Cretaceous is widely regarded as a time of great evolutionary transition for the freshwater fish fauna of North America, the fossil record of this period is notoriously poor, consisting mostly of fragments and isolated skeletal elements. Exceptions include the acipenseriforms, discussed in this paper, and some exceedingly rare teleosts. Here we describe two new species of well-preserved sturgeons (Acipenseridae) from the Tanis site in the Late Cretaceous Hell Creek Formation of North Dakota. The type and referred materials were preserved in a loosely consolidated matrix. †Acipenser praeparatorum n. sp. is represented by multiple body fossils (including the head and relatively complete postcranial remains) and a specimen of an intact, three dimensionally preserved skull and pectoral girdle. This taxon can be diagnosed based on features of the opercular elements (exceptionally tall and narrow branchiostegal). The second species, †Acipenser anisinferos n. sp., is represented by a partially preserved skull, and can be diagnosed by a relatively elongate preorbital region (i.e., snout) and the absence of thorn-like spines on the skull roofing bones. Most known sturgeon fossils from the Cretaceous are represented only by undiagnosable fragmentary remains (i.e., scutes and pectoral-fin spines) or poorly preserved partial skeletons (e.g., †Protoscaphirhynchus), with †Priscosturion and †Anchiacipenser (both monotypic) being rare exceptions. Therefore, the newly discovered Tanis fossils give a rare glimpse into the evolution of Acipenseridae at a critical time in the phylogenetic history of acipenseriforms, and suggest significant morphological and taxonomic diversity early in the evolution of this group.

UUID: http://zoobank.org/375b586a-2dd8-4a31-b6c4-42151e6e8fc8

Non-archosaur archosauromorphs are a paraphyletic group of diapsid reptiles that were important members of global Middle and Late Triassic continental ecosystems. Included in this group are the azendohsaurids, a clade of allokotosaurians (kuehneosaurids and Azendohsauridae + Trilophosauridae) that retain the plesiomorphic archosauromorph postcranial body plan but evolved disparate cranial features that converge on later dinosaurian anatomy, including sauropodomorph-like marginal dentition and ceratopsian-like postorbital horns. Here we describe a new malerisaurine azendohsaurid from two monodominant bonebeds in the Blue Mesa Member, Chinle Formation (Late Triassic, ca. 218–220 Ma); the first occurs at Petrified Forest National Park and preserves a minimum of eight individuals of varying sizes, and the second occurs near St. Johns, Arizona. Puercosuchus traverorum n. gen. n. sp. is a carnivorous malerisaurine that is closely related to Malerisaurus robinsonae from the Maleri Formation of India and to Malerisaurus langstoni from the Dockum Group of western Texas. Dentigerous elements from Puercosuchus traverorum n. gen. n. sp. confirm that some Late Triassic tooth morphotypes thought to represent early dinosaurs cannot be differentiated from, and likely pertain to, Puercosuchus-like malerisaurine taxa. These bonebeds from northern Arizona support the hypothesis that non-archosauriform archosauromorphs were locally diverse near the middle Norian and experienced an extinction event prior to the end-Triassic mass extinction coincidental with the Adamanian-Revueltian boundary recognized at Petrified Forest National Park. The relatively late age of this early-diverging taxon (Norian) suggests that the diversity of azendohsaurids is underrepresented in Middle and Late Triassic fossil records around the world.

UUID: http://zoobank.org/e6eeefd2-a0ae-47fc-8604-9f45af8c1147.

Platymerella from the lower Red Mountain Formation in Georgia and Tennessee, the Bowling Green Dolomite of west-central Illinois, and the Elwood Dolomite of northeastern Illinois represents a paleosubtropical, cool-water occurrence of virgianid brachiopods in Laurentia during the early Silurian (middle–late Rhuddanian). These occurrences were located in the southern Appalachian foreland basin and the distal end of the Sebree Trough, likely subjected to frequent cool-water current and upwelling from Gondwana. Compared with broadly coeval species of Virgiana from lower paleotropical to equatorial latitudes, Platymerella has significantly smaller, dorsoventrally flattened shells, with subequal ventral and dorsal umbones and beaks that extend only slightly above the hinge line. Relative to its shell size, however, Platymerella has more prominent thickening of the shell wall, median septum, spondylium, and hinge plates than Virgiana, resembling more closely the extravagant shell thickening of Tcherskidium and Proconchidium from the Late Ordovician (late Katian) equatorial regions. The thickening of hinge plates resulted in the formation of a pseudocruralium, which separates Platymerella from Virgiana. In latest Ordovician–earliest Silurian virgianids, there was a general morphological gradient toward a smaller shell, reduction in the ventral-valve convexity, and reduction in the size and height of the ventral umbo from paleoequatorial to southern subtropical regions, with Platymerella representing the most southerly forms.

The early geologic history of family Pinnidae, a diverse and abundant component of mud-dominated shallow marine environments of the late Paleozoic, is obscured by ill-defined genus and species concepts. Mistakes in descriptions and reconstructions have provided a basis for suggestions that older taxa in the family differ from younger taxa and may not belong in family Pinnidae. This report provides improved documentation that removes the basis for the concept of divergence. Late Paleozoic genera and species have definite pinnid bivalve characters, including a dorsomarginal fold that holds the ligament, a thick outer columnar prismatic shell layer, and an equivalved, triangular shell, all of which provide evidence for confident assignment of the genus to family Pinnidae. The suggested synonymy of Aviculopinna with Pteronites is invalid, and genus Aviculopinna is limited to occurrence in Permian strata. The two genera belong in different families. A neotype is designated for genus Aviculopinna type species Aviculopinna pinnaeformis Geinitz from Gera, Germany, and a lectotype for Aviculopinna neukirchensis Langenhan from Nowy Kościół, Poland. Inferences on the life habits of Aviculopinna based on its occurrence in Poland are presented. An evaluation of the subterminal beak versus terminal beak concept in pinnids is presented and conclusion presented that there are few data available to support the concept or to test it. In its present form, the concept has no utility in the study of pinnid bivalves.

This work describes a rhynchonellid and spire-bearing brachiopod fauna from the Ixtaltepec Formation of Oaxaca, Mexico. Leiorhynchoidea perrilliatae, Allorhynchus scientiana, and Anthracospirifer oaxacaensis are new species. The specific determination, along with information of previously described taxa, allowed the establishment of precise relative ages of the different fossiliferous intervals (API-1 to API-8) of the formation. The occurrence of Serpukhovian taxa in API-1 to API-3 allowed assignment of the strata to the Upper Mississippian. The presence of Bashkirian species allowed the assignment of the rocks of API-5 and API-6 to the Lower Pennsylvanian. Likewise, Middle Pennsylvanian brachiopods in API-7 and API-8 enabled correlation of the strata with the Moscovian stage. This study shows that the Ixtaltepec Formation is represented by a succession of well-delimited Serpukhovian, Bashkirian, and Moscovian rocks. Regarding paleogeography, the brachiopod fauna displays clear taxonomic variations that concur with global geological changes that occurred between the Serpukhovian to Moscovian. In the Serpukhovian intervals, we recorded numerous cosmopolitan taxa of tropical waters, coinciding with the migration pathway of the Rheic Ocean. For the Bashkirian, we observed a North American provincialism; however, because of the presence of Australian and South American species, it is proposed that the Austropanthalassic-Rheic corridor had a close connection with Oaxaca. The main provincialism was observed in the Moscovian association because most of those taxa have been reported from different localities in the United States. This study supports that the main resemblance between Oaxacan and North American faunas continued until the Pennsylvanian and not the Mississippian, as was previously proposed.

UUID: http://zoobank.org/181e49cf-a08a-4e99-8200-65f4a90dafcd

A highly diversified fauna of hermit crabs associated with reef environments from the Serraduy Formation (lower Eocene) in the southern Pyrenees (Huesca, Spain) is described. Other European Eocene outcrops have yielded paguroids associated with a single environment; however, the studied association represents one of the highest paguroid diversities in a single Eocene outcrop worldwide. The new material increases the diversity of known fossil paguroids, including eight species from which six are new: Clibanarius isabenaensis n. sp., Parapetrochirus serratus n. sp., Dardanus balaitus n. sp., ?Petrochirus sp., Eocalcinus veteris n. sp., ?Pagurus sp., Paguristes perlatus n. sp., and Anisopagurus primigenius n. sp. We erected a new combination for Paguristes sossanensis De Angeli and Caporiondo, 2009 and Paguristes cecconi De Angeli and Caporiondo, 2017 and transfer them to the genus Clibanarius. This association contains the oldest record of the genera Eocalcinus and Anisopagurus. Our data demonstrate that paguroids were diverse by the early Eocene in coral-reef environments and fill an important gap between the poorly known Paleocene assemblages and the more diverse mid- to late Eocene ones.

UUID: http://zoobank.org/091f7a79-946c-4cd9-bdad-f727695e8503