Upper Devonian (Famennian) sequences were sampled at two sections in the Canning Basin, Western Australia, and a section at Bactrian Mountain, Nevada, over an interval ranging from the Upper crepida Zone into the Lower marginifera Zone of the standard conodont zonation for the Famennian. Over 30,000 conodont elements have been identified among 43 species and subspecies within six genera. New complete and partial multielement reconstructions are illustrated for: Palmatolepis falcata, P. glabra prima, P. loba, P. minuta minuta, P. perlobata perlobata, P. perlobata maxima, P. quadrantinodosalobata, P. rhomboidea, P. schindewolfi, P. subgracilis, P. wolskae, Polygnathus cf. P. diversus, P. glaber glaber, P. nodocostatus nodocostatus, P. subnormalis, and P. cf. P. triphyllatus. The reconstructions are based on stratigraphic occurrence, detailed morphologic similarities, and a few exceptional low-diversity faunas. Additionally, Palmatolepis adamantea n. sp. is proposed based on the Pa element.

A more precise understanding of the taxonomic boundaries of Palmatolepis is achieved through knowledge of the entire apparatus, rather than confined to the Pa elements. Reconstructions presented here provide a more comprehensive understanding of the range of morphologic variation that exists in Palmatolepis, and show that a single generalized elemental plan can be demonstrated for all members of the genus. The differences in the non-Pa elements can thus be used to refine taxonomy and increase understanding of phylogenetic relationships at the specific and subspecific level.

This paper describes cranial and postcranial remains from Alligator olseni White, 1942 and Alligator cf. mefferdi Mook, 1946. An earlier phylogenetic data set has been augmented with new data from these fossils. Although membership in the clade Alligator is generally in accord with previous analyses, neither strict consensus nor Adams consensus trees could resolve placement of all members. Several lines of evidence pertinent to Alligator biogeography are analyzed. Alligator may have dispersed from North America into Asia prior to 15 million years ago, but conclusive evidence is lacking.

Echinoids are among the most conspicuous and diverse constituents of the Upper Cretaceous and Paleocene marine invertebrate fauna of Argentina. Nine species were collected from localities exposing the Jagüel (Maastrichtian), Roca (Maastrichtian–Danian), Salamanca (Danian), Arroyo Barbudo (Danian), El Fuerte (Danian), and Arroyo Salado (Danian) Formations in northern Patagonia, Argentina. Only one of these taxa, Paraster joannisboehmi (Oppenheim in Böhm, 1903), has been described previously from Argentina. Four taxa, Gauthieria menuthiae (Lambert and Savin in Lambert and Thiéry, 1911), Nucleopygus pullatus (Stoliczka, 1873), Diplodetus nutrix (Lambert in Boule, 1899), and Hemiaster hawkinsi Lambert, 1933, have been described previously from Madagascar. One species, Micropsis desori (Cotteau in Leymerie and Cotteau, 1856), has been described previously from France. One taxon, Pygopistes parrasae is a new species. Argentinian cassiduloids include the only two known Danian species of Nucleopygus and Pygopistes. The spatangoids were not strongly affected by the K-T extinction event. Comparisons of the Patagonian echinoids with those of the Northern Hemisphere indicate that they were strongly influenced by dispersal from Tethyan sources.

The fixosessile, perireefal to reefal Devonian epibiont Davidsonia cemented itself by its entire ventral valve to the underside of alveolitid tabulate corals, or to stromatoporoid sponges. It occupied a cryptic niche in perireefal biostromal thickets to reef complexes in the Old World faunal realm (Europe, western North America), and Uralian–Central Asian faunal province. A new species, D. septata, is here reported in abundance for the first time from Middle Devonian (Givetian) rocks of Yunnan, thus extending its range to South China. The usual absence of the brachial valve is suggested to be due to postmortem taphonomy as a result of its unique, cemented mode of life on the undersides of corals or sponges. A new genus of coarsely ribbed, partly libero-, partly fixosessile davidsoniid, Rugodavidsonia, type Davidsonia woodwardiana (DeKoninck), mimicking unrelated Late Paleozoic orthotetids, is also described, demonstrating that ribs evolved secondarily in a family dominated from its inception by smooth shells. Its paleogeographic distribution ranged from Europe through western North America (and possibly China), commonly accompanying Davidsonia in similar assemblages, but with a slightly different mode of life. Reexamination of available material, using thin sections, peels and SEM, confirms that the impunctate shell structure, dorsally directed spiralia, nature of the hinge mechanism, the deltidial plates, absence of a chilidium, “atrypoid” musculature and vascular markings, show features in Davidsonia and Rugodavidsonia that are all typical of the Order Atrypida. Thus, Davidsonia demonstrates that ventral valve cementation evolved independently more than once in articulate brachiopods such as strophomenids, productids, atrypids, and thecideid spiriferids. A revised classification of the Davidsonioidea and Palaferelloidea is proposed. Relationships between various genera are outlined in a new family tree for these groups. The various families discussed, including the Symmatrypidae, are united under a new suborder, the Davidsoniidina, a primarily carbonate platform and perireefal dwelling group, which first evolved during the Ludlovian (Late Silurian) in the Uralian–Central Asian tropical shelf region, diversified over a period of ~47 Ma, and then died out during the late Givetian, 10 Ma prior to the Frasnian–Famenian mass extinction events.

A previously undocumented echinoid fauna occurs in the terrigenous clastic sedimentary sequence of the Old Pera Beds (Lower Pleistocene) and the overlying Port Morant Formation (Upper Pleistocene) at Old Pera, parish of St. Thomas, southeast Jamaica. The fauna is comprised of complete tests (particularly from two horizons in the Port Morant Formation), test fragments, and radioles, and includes: Cidaris (Tretocidaris) bartletti (A. Agassiz); Eucidaris tribuloides (Lamarck); diadematoid indet. gen. and sp.; Echinometra viridis A. Agassiz; Echinometra? sp.; Clypeaster rosaceus (Linné); a juvenile C. subdepressus? (Gray); mellitid indet. gen. and sp.; clypeasteroid sp.; Schizaster doederleini Chesher; Meoma ventricosa (Lamarck); and irregular indet. gen. and sp. Schizaster doederleini is still extant in the Caribbean, but is not known to live in Jamaican waters. Schizaster doederleini and Meoma ventricosa are the first nominal spatangoids to be reported from the Jamaican Pleistocene.

Five land snails and the borings of marine bivalves are reported from Hkamti (Khamti) amber whose age was recently uranium-lead dated to be ca. 110 Ma, in contrast to the nearby Kachin (‘Burmese’) amber considered to be ca. 99 Ma. Four of the snails belong to Cyclophoridae, and although their condition does not allow unambiguous identification or description of the species, one of them strongly resembles Archaeocyclotus plicatula Asato and Hirano in Hirano et al., 2019 from Kachin amber. The fifth snail, Euthema myanmarica n. sp. (Diplommatinidae), is a representative of a genus that was known exclusively from Kachin amber until now. The genus Euthema Yu, Wang, and Pan, 2018 is revised, with a new synonym, Xenostoma Bullis et al., 2020. The recently described ‘Truncatellina dilatatus’ Yu, 2020 from Kachin amber is placed in Euthema. A comparison of the distinguishing characters of the eight Euthema species is provided. The borings of bivalves in Hkamti amber correspond to the ichnospecies Teredolites clavatus Leymerie, 1842, associated with the bivalve genus Martesia Sowerby, 1824 (Pholadidae), and are common in Kachin amber. Similarity of the malacofauna from Hkamti and Kachin ambers, as well as the presence of numerous, similar Teredolites clavatus, indicates that these ambers were formed in very similar paleoenvironments. This indication suggests that forests with very similar conditions existed throughout the entire Albian to the early Cenomanian, or that the dating of at least one of these amber deposits is incorrect. In the latter case, it would mean that Kachin amber is at least 110 Ma or older.

UUID: http://zoobank.org/142f10a2-307f-4053-9b29-8aa18db66219

The axial column in Labidosaurus is thoroughly described. Two different vertebral “morphs” are found to occur in this genus. One type is that which is classically illustrated for Labidosaurus, while the other shows alternation in height and construction of the neural arches and neural spines. A brief description of the modifications of muscle attachments in alternating forms is outlined. Analysis shows that such a structural modification probably allowed (more) efficient dorsiflexion and lateral flexion of the vertebral column. The occurrence of alternation of neural spine and arch structure is probably a primitive characteristic, but becomes variously modified in different forms. The variability observed in the axial column suggests that Labidosaurus may have been sexually dimorphic, or that the genus may consist of two different species.

We used up to 30 morphological characters to discriminate and describe species of the genus Discoporella based on complete colony specimens collected from both coasts of the Isthmus of Panama. The characters included zooidal characters and colony-level characters such as colony size and basal granule density. Species were classified by a series of multivariate cluster and linear discriminant analyses until the majority of specimens were assigned to their putative species with high confidence. In the first phase of the analyses, the colonies were grouped by ocean (Caribbean versus eastern Pacific), discriminated predominantly by colony size and basal granule density, characters that might reflect ecophenotypic responses to different conditions in primary productivity and predation between the two oceans. Further analyses of these two groups separately resulted in the discrimination of seven species. Five new species from the Caribbean (D. scutella, D. peltifera, D. bocasdeltoroensis, D. terminata and D. triangula), and two from the eastern Pacific (D. marcusorum and D. cookae). Of these, D. cookae had been identified previously as D. umbellata, a species once considered cosmopolitan, with a range spanning the Caribbean and eastern Pacific coasts of America. With the exception of one genetically defined clade represented by only two specimens, the correspondence of classification between groups discriminated morphometrically by separate step-wise multivariate analyses and those detected by a previous genetic analysis, ranged from 91% to 100%. In analyses of all specimens combined or separated by ocean, but using the total number of characters, 20% to 30% of the specimens could not be distinguished morphometrically from extremely similar sympatric species or cognate (“geminate”) species from the opposite ocean. Diversity was higher in the Caribbean compared to the eastern Pacific, which reflects a similar pattern recently described for the genus Cupuladria from the same region.

The Upper Ordovician (lower Katian) Bobcaygeon and Verulam formations from the Lake Simcoe region of Ontario contain a highly diverse echinoderm assemblage that is herein recognized as a Konservat-Lagerstätte. Although fossil crinoids have long been recognized from these formations, the fauna has not received a comprehensive taxonomic evaluation since Springer’s classic 1911 monograph. Recent extensive collection and preparation of new material from the Bobcaygeon and Verulam formations near Brechin, Ontario recovered numerous exceptionally preserved crinoid specimens with arms, stems, and attachment structures intact. The Brechin Lagerstätte is the most taxonomically diverse Katian crinoid fauna, with more than 20 crinoid genera represented in this collection.

Here, all dicyclic crinoids belonging to subclass Camerata from the Brechin Lagerstätte are evaluated. The following four genera and seven species are described from the fauna, including one new genus and four new species: Reteocrinus stellaris, Reteocrinus alveolatus, Archaeocrinus sundayae n. sp., Archaeocrinus maraensis n. sp., Priscillacrinus elegans n. gen. n. sp., Cleiocrinus regius, and Cleiocrinus lepidotus n. sp. The exceptional preservation of this collection provides an opportunity to describe more fully the morphologic and ontogenetic details of known Ordovician crinoid taxa, to conduct a taxonomic re-evaluation of many species, to describe new taxa, and to provide a framework for subsequent studies of crinoid community paleoecology.

UUID: http://zoobank.org/e3e268a7-88e5-43cd-84ea-b40df45e8281

The Upper Triassic of the Williston Lake area of northeastern British Columbia is represented by a nearly continuous series of fossil-rich sediments that were deposited in the Western Canadian Sedimentary Basin in an offshore mid-paleolatitude setting on the western margin of cratonic Pangea. The fossils in this report come primarily from the upper Carnian–upper Norian Pardonet Formation, which has been the subject of numerous paleontologic studies on ammonoids and conodonts, yet has received little attention with regard to its bivalve fauna. Fossil bivalves belonging to the thin-shelled bivalve genera Halobia, Eomonotis, and Monotis dominate the benthic macrofauna and occur within unique shell accumulations that are interpreted to represent oxygen-controlled monospecific paleocommumities that have undergone little post-mortem transportation. Systematic analyses of more than 1,000 individual bivalve specimens resulted in the identification of 25 species-rank taxa, a majority of which belong to the pterioid genus Halobia and the pectinoid genera Eomonotis and Monotis. Of these, four new species are recognized, including 1) upper Carnian Halobia tozeri n. sp. characterized by a unique triangular outline; 2) lowermost Norian Halobia selwyni n. sp. closely related to H. beyrichi and first appearing with H. austriaca which is proposed as a potential datum for the Carnian–Norian boundary; 3) Norian Meleagrinella mclearni n. sp., a new name for previously identified species; and 4) upper Norian Otaparia norica n. sp. which has a delicate thin shell, unique outline, and fine ornament. A revised and refined biochronology of Upper Triassic Bivalvia (chiefly Halobiidae and Monotidae) integrated with conodont and ammonoid zones and standard Triassic stages is presented for the Upper Triassic of the Williston Lake area and permits enhanced correlation to coeval faunas elsewhere in the North American Cordillera, and to the Boreal, Panthalassan and Tethyan faunal realms.

An assemblage of seventeen species of Small Shelly Fossils, dominated by the brachiopod Eothele tubulus and species of the mollusk Yochelcionella, is described from the basal Kinzers Formation of Thomasville, Pennsylvania. The occurrence extends southwards the distribution of an Early Cambrian fauna (Cambrian Series 2, Stage 4) that is otherwise characteristic of the eastern shelf of Laurentia from New York to Greenland. The poorly known acrothelid brachiopod Eothele tubulus is redescribed based on large collections of ventral valves. The shell structure of E. tubulus is characterized by orthogonal baculae, and represents the oldest known example of a baculate shell structure, indicating that this type of shell structure evolved already in the Early Cambrian.

Large trace fossils attributed to the ichnogenus Psilonichnus (Fürsich) have been identified in subtidal sediments of the Red Crag Formation (late Pliocene) of Walton-on-the-Naze, Essex, U.K. The traces are vertical or inclined, tapering cylindrical structures, occasionally branched, up to 2.3 m long. The structures are mud-rich relative to the surrounding sediment and their fills often show a spiralling grain fabric. The ichnogenus Psilonichnus has formerly been attributed to the burrowing activities of intertidal and supratidal crab species. The known fossil crab assemblage of the Red Crag contains no deep burrowing species. The traces are thus attributed to other crustaceans, possibly thalassinidean shrimps. The occurrence indicates that Psilonichnus may have a greater palaeoenvironmental range than previously realized.

Unlike the Asian and North American Pliocene record, fossil occurrences of Canidae in Europe (and Africa) are uncommon and fragmentary. The revision of canid material from the late Pliocene site of Kvabebi (eastern Georgia) revealed the contemporaneous occurrence of three different taxa: (1) Nyctereutes megamastoides (a derived species of the Eurasian Pliocene raccoon dog-like canids); (2) Vulpes cf. V. alopecoides (representing the first occurrence of a member of the vulpine taxon V. alopecoides, a species that was the most widespread fox in the early Pleistocene in western Europe); and (3) Eucyon sp. The latter occurrence at Kvabebi completes our knowledge of the late Pliocene evolutionary history of the latest representatives of the genus in Western Europe and Central Asia. Our revision of Kvabebi canids registers a previously undocumented case of established niche partitioning among early Pliocene sympatric Canidae.

A paleoecological study of benthic foraminifera through the lower Hettangian in the Doniford Bay section (west Somerset, U.K.) is presented. The sudden and brief appearance of Oberhauserellidae in the aftermath of the Late Triassic extinction is defined as a proxy for environmental perturbations indicating severe biotic stress conditions. Oberhauserellidae, associated with the genus Reinholdella are distinguished from other species by a high abundance, low diversity, high dominance and an abnormally small size. This suite of characters mimics an opportunistic behavior where these r-strategists and grazer feeders maximize their full ecological potential at a time of low-oxygen conditions on the sea-floor and a high food supply: both of which appear to be the main triggers of this paleoecological change. The disappearance of these opportunistic benthic foraminifera coincides with the appearance of infaunal, low-oxygen-tolerant generalists, and the restoration of stable environmental conditions (e.g., well-stratified water mass and oligotrophic conditions), characterizing the initial stages of recovery following the Late Triassic extinction event.

Eospongilla morrisonensis n. gen. and sp., the oldest-described freshwater sponge (Demospongea: Spongillidae), is found in the Upper Jurassic (?Oxfordian/Kimmeridgian to Tithonian) Morrison Formation, east-central Colorado, U.S.A. Eospongilla morrisonensis occurs within the well-developed lacustrine carbonate succession of the Morrison Formation, and is represented by two micritic body fossils with calcite-replaced megascleres that range in length from 180 to 300 μm and in diameter from 20 to 35 μm. Megascleres are simple oxeas and strongyles and lack apparent ornamentation, possibly due to the diagenetic replacement. The oxeas are straight but the strongyles display a slight curvature. Microscleres are absent; gemmoscleres were not observed.

The peridiniacean dinoflagellate cyst Manumiella seymourensis new species described herein characterizes Maastrichtian shallow marine sediments cropping out on Seymour Island, northeastern Antarctic Peninsula. It dominates palynological assemblages throughout the lower Maastrichtian (and possibly uppermost Campanian) to lower upper Maastrichtian part of the López de Bertodano Formation. Despite its superficial similarity to some other southern mid to high paleolatitude Campanian-Maastrichtian species, M. seymourensis represents a discrete, biostratigraphically useful population of peridiniacean cysts. Its morphology and size parameters remain consistent throughout almost all of its stratigraphic range, equated with relatively stable environmental conditions throughout much of the Maastrichtian in the James Ross Basin. Morphological variations, equated with environmental change, are apparent in specimens in the lowermost and uppermost parts of its range.

A number of immature and mature exoskeletons allow the first detailed description of the ontogeny of the early Cambrian redlichiid trilobite Metaredlichia cylindrica, from black shale of the Shuijingtuo Formation in Hubei Province, South China. The material includes numerous complete protaspides, within which two stages can be differentiated according to the appearance of a shallow furrow that separates the protopygidial area from the protocranidium. Also, identification of the subsequent ontogenetic stages, including meraspides and holaspides, depends on isolated cranidia that display prominent morphological changes such as the contraction of frontal glabellar lobe, appearance of the fourth pair of glabellar furrows, and modification of the facial suture from proparian to opisthoparian. Incorporating the whole ontogenetic sequence allows us not only to trace the developmental trends of various structures with growth, but also to assign the protaspides to their adults correctly, particularly with the help of meraspid specimens.

Stromatoporoids from the Late Devonian (early Frasnian) Waterways Formation near Fort McMurray, Alberta, contain well preserved Trypanites Mägdefrau. The stromatoporoid heads are formed of an initial growth of Clathrocoilona inconstans Stearn that is encased by a second stage growth of Trupetostroma papulosum Stearn. These two stages were separated by a period of no growth and erosion. The first two generations of boring penetrated the skeleton of C. inconstans while the third generation borings penetrated both C. inconstans and T. papulosum. The borings in the stromatoporoids are filled with light colored micrite, dark colored micrite, skeletal fragments, dolomite, non-ferroan calcite, and ferroan calcite. Analysis of the borings, the growth stages of the stromatoporoids, the boring fill, and the orientation of the geopetal fabrics indicates that the stromatoporoids were subjected to repeated cycles of growth-boring-filling and reorientation. This complex interaction of biologic and physical reworking had a profound influence on the diagenetic transformation of the stromatoporoid heads. This example clearly illustrates the role that biogenic agents can play in the production of diagenetic fabrics of hard carbonate substrates.

Paleozoic echinoids are exceptionally rare, and little is known of their paleoenvironmental distribution. The echinoid fauna of the Fort Payne Formation (Late Osagean, Early Viséan) of south-central Kentucky is documented. Four genera, ?Archaeocidaris, Lepidocidaris, ?Lepidesthes, and an unidentified lepidocentrid, were recovered and represent three different families. This fauna, and their associated paleoenvironments, give important new insights into the facies distribution of Paleozoic echinoids and the taphonomic biases that affect this distribution. Lepidocidaris is known from the green shale facies, which comprises the core of Fort Payne’s carbonate buildups. ?Archaeocidaris and the lepidocentrid are known from the wackestone buildups and crinoidal packstone buildups. ?Lepidesthes is also known from crinoidal packstone and wackestone buildups, which argues against a semi-infaunal life mode for this taxon. All relatively semiarticulated echinoids were known from autochthonous facies, whereas the only echinoids from the allochthonous facies were disarticulated hemipyramids. Furthermore, deeper-water carbonate buildups were apparently capable of supporting diverse echinoid faunas during the Viséan.

The thickness ratios of shells (=whorl breadth/shell diameter) in the heteromorphic scaphitid ammonoid Scaphites planus (Yabe, 1910) from the lower middle Turonian in the Oyubari and Kotanbetsu areas of Hokkaido, Japan were examined in order to determine their mode of migration. The thickness ratios of S. planus differ significantly between the two localities, which suggest that these different populations did not frequently migrate between the two areas (currently ∼130 km apart, although the actual distance during Turonian is uncertain due to the presence of faults and folds between the two areas). There is no difference in hatchling diameters between the two areas, suggesting that the thickness ratios became manifested after the post-hatchling stage due to limited migration with in a nektobenthic habitat. This study suggests that scaphitid ammonoids became nektobenthic with limited migration at a stage earlier than previously thought (not during the transition from normal to abnormal coiling). The limited migration in scaphitid ammonoids might relate to their higher evolutionary volatility.