Clathrodictyids are the most abundant stromatoporoids in the Upper Ordovician Xiazhen Formation (middle to upper Katian) of South China. A total of nine species belonging to four clathrodictyid genera are identified in the formation, including Clathrodictyon idense Webby and Banks, 1976, Clathrodictyon cf. Cl. microundulatum Nestor, 1964, Clathrodictyon cf. Cl. mammillatum (Schmidt, 1858), Clathrodictyon megalamellatum Jeon n. sp., Clathrodictyon plicatum Webby and Banks, 1976, Ecclimadictyon nestori Webby, 1969, Ecclimadictyon undatum Webby and Banks, 1976, Camptodictyon amzassensis (Khalfina, 1960), and Labyrinthodictyon cascum (Webby and Morris, 1976). The clathrodictyid fauna in the Xiazhen Formation is very similar to those from both New South Wales and Tasmania, although the latter two Australian regions do not share any common clathrodictyid species during the Late Ordovician. The paleobiogeographic pattern indicates that the northward drift of South China resulted in a favorable environment for the migration of clathrodictyids from other peri-Gondwanan terranes to South China. In addition, these peri-Gondwanan clathrodictyid species hosted various endobionts, representing a variety of paleoecological interactions. The high abundance and species-level diversity of clathrodictyid species presumably increased the substrate availability of suitable host taxa, judging from the diverse intergrowth associations between clathrodictyids and other benthic organisms. These paleoecological interactions between stromatoporoid and other organisms are known from the Late Ordovician and became more abundant and widespread in the Siluro–Devonian. Overall, the Late Ordovician clathrodictyid assemblage in South China demonstrates one of the highest species-level diversities among all peri-Gondwanan terranes and represents a precursor of the complex, clathrodictyid-dominated communities of later metazoan reefs during the Great Ordovician Biodiversification Event.

UUID: http://zoobank.org/6063c47d-cb77-4a03-98cf-b2354656dea6

Plant fossils from the Tertiary strata of the Great Plains are relatively common and have been reported for over 100 years (Stansbury, 1852; Elias, 1942; Thomasson, 1979, 1985, 1991; Gabel, 1987). However, fossils of the family Cyperaceae are uncommon at most sites in Tertiary strata of central North America.

Bivalves of the Order Trigoniida were abundant and diverse in the Andean Early Jurassic shallow-marine paleoenvironments. Based on extensive collections with detailed stratigraphic information from 40 localities in central-western Argentina, we describe 20 species (4 new) belonging to 11 genera (3 new) and 5 families (Groeberellidae, Trigoniidae, Prosogyrotrigoniidae, Frenguelliellidae, and Myophorellidae). The abundant material allows the description of ontogenetic development and intraspecific variability, highlighting the likely phylogenetic significance of previously underestimated features. Within Frenguelliellidae, we show that the stratigraphic range of Frenguelliella Leanza in the region is restricted to the Sinemurian–Pliensbachian. We propose Poultoniella new genus for some late Pliensbachian–Toarcian species. Jaworskiella Leanza is limited to its type species, whereas for certain convergent forms we propose Moerickella new genus (most likely the oldest Myophorellidae). Pseudovaugonia new genus likely descended from Moerickella n. gen., rather than from the highly diverse Promyophorella Kobayashi and Tamura, and is unrelated to Vaugonia Crickmay. Frenguelliella chubutensis (Feruglio) and Promyophorella basoaltorum new species are the most frequently occurring species. Some species were probably endemic (e.g., Promyophorella? sanjuanina new species), although a few (such as Frenguelliella eopacifica new species and Poultoniella jaworskii new genus new species) had a wide paleolatitudinal range and occur throughout the Pacific coasts and terranes of the Americas, revealing a significant faunal interchange among marine basins during Hettangian–Pliensbachian times. The well-documented Argentinian Early Jurassic record shows a rapid recovery and radiation of the Trigoniida after the Triassic/Jurassic extinction. Many of the new taxa that evolved in America eventually dispersed worldwide by Toarcian and Middle Jurassic times.

UUID: http://zoobank.org/82c0d95e-f147-4736-a417-ebc252911181.

The lower strata of the Umachiri Formation from the Altiplano of southeast Peru have yielded a brachiopod-dominated assemblage, containing representatives of the brachiopod superfamilies Polytoechioidea, Orthoidea, and Porambonitoidea, as well as subsidiary trilobite and echinoderm remains. Two new polytoechioid genera and species, Enriquetoechia umachiriensis new genus new species and Altiplanotoechia hodgini n. gen. n. sp. Colmenar in Colmenar and Hodgin, 2020, and one new species, Pomatotrema laubacheri n. sp., are described. The presence of Pomatotrema in the Peruvian Altiplano represents the occurrence at highest paleolatitude of this genus, normally restricted to low-latitude successions from Laurentia and South China. Other polytoechioids belonging to Tritoechia (Tritoechia) and Tritoechia (Parvitritoechia) also occur. Identified species of orthoids from the genera Paralenorthis, Mollesella, and Panderina? occur in the Peruvian Cordillera Oriental and in the Argentinian Famatina Range. The only porambonitoid represented is closely related to Rugostrophia latireticulata Neuman, 1976 from New World Island, interpreted as peri-Laurentian. These brachiopod occurrences indicate a strong biogeographic affinity of the Peruvian Altiplano with the Famatina and western Puna regions, suggesting that the brachiopod faunas of the Peruvian Altiplano, Famatina, and western Puna belonged to a well-differentiated biogeographical subprovince during the Early–Middle Ordovician on the margin of southwestern Gondwana. Links with peri-Laurentian and other low-latitude terranes could be explained by island hopping and/or continuous island arcs, which might facilitate brachiopod larvae dispersal from the Peruvian Altiplano to those terranes across the Iapetus Ocean. Brachiopods from the lower part of the Umachiri Formation indicate a Floian–?Dapingian age, becoming the oldest Ordovician fossils of the Peruvian Altiplano.

UUID: http://zoobank.org/9670a000-260d-4d75-9261-110854c7afb8

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

Based on multivariate morphometric analysis, Halysites catenularius is identified from the Rumba Formation (Telychian) and Jaagarahu Formation (Sheinwoodian) of Estonia; H. priscus is confirmed as a junior synonym. Halysites catenularius, H. junior, and H. senior are shown to be closely related; H. catenularius is morphologically intermediate. Cyclomorphism in H. catenularius, recorded by fluctuations of corallite tabularial area, indicates an average annual growth rate of 6.0 mm, which is typical for halysitids. Tubules in H. catenularius, generated from small intramural openings between adjacent corallites, were involved in two types of interstitial increase. The intramural openings, three types of lateral increase, temporary agglutinated patches of corallites, and axial increase documented in H. catenularius resemble features in some species of Catenipora. These similarities are consistent with the interpretation that Halysites evolved from Catenipora. Evaluation of the possibility that both genera are polyphyletic will require further detailed analysis of additional species.

Members of the Lyttoniidae Waagen, 1883 (Lyttonioidea Waagen, 1883, Brachiopoda) are characterized by numerous peculiarities, including their disproportionately inequivalve, rudimentary articulatory apparatus and asymmetrically developed muscle scars. The ventral valve of lyttonioids usually possesses a posterior flap and complementary septal apparatus and the dorsal valve has corresponding lobes and slits to fit around the ventral septa (Noetling, 1905; Fredericks, 1926; Wanner, 1935; Williams, 1953; Grant, 1976; Williams et al., 2000). Externally, the Lyttoniidae have been previously described as being smooth or having some growth banding, lines, or disturbances only (Cooper and Grant, 1974; Williams et al., 2000). Spines were previously reported by Sarytcheva (1964), but subsequently not confirmed by Cooper and Grant (1974, p. 387) and Williams et al. (2000). Radial ornamentation has never been reported prior to this study. In 2002, two specimens with Linoproductus-like costellae and Old-hamina-like septal apparatus were found by one of the authors (CLR) from the Middle Permian Xiala Formation at the Xinji Section in the Xainza area (89–91°E, 30–31°N) in northern Tibet (Fig. 1.1, 1.2) during 1:250,000 mapping. We consider that the present specimens represent another distinct phylogenetic branch within the Lyttoniidae, although only two specimens were found. Further collecting is currently impossible because of the inaccessibility of the remote area in northern Tibet. In this paper we aim to propose a new subfamily of Lyttoniidae based on the specimens found from northern Tibet.

A small faunule of hypercalcified agelasiid demosponges has been recovered from outcrops of the Silurian Heceta Formation on Prince of Wales Island in southeastern Alaska. Included are abundant Girtyocoeliana epiporata (Rigby and Potter, 1986), of the Girtyocoeliidae Finks and Rigby, 2004; fragments of Alaskaspongiella laminosa n. gen. and sp., Polyplacospongia nodosa n. gen. and sp., and Monolaminospongia gigantia n. gen. and sp., of the Auriculospongiidae Termier and Termier, 1977, and Cladospongia alaskensis n. gen. and sp., Virgulaspongia uniforma n. gen. and sp., and Stipespongia laminata n. gen. and sp. of the Preperonidellidae Finks and Rigby, 2004. Also included are a few fossils of uncertain taxonomic placement, including Turbospongia biperforata n. gen. and sp., along with a small, chambered, tubular fragment and several porous tubular stems that may be additional poriferans. Some isolated octactine-based heteractinid spicules were also recovered from the etched residues.

An exceptionally well-preserved specimen of Leptochiton sp. attached to a brachiopod valve is described from the early Eocene beds of the La Meseta Formation, Seymour Island. It records the first fossil Polyplacophora from Antarctica. The small specimen has eight imbricating valves, rounded lateral margins, ribs of fine granules, and growth marks in all valves. It strongly resembles extant Antarctic and South American species of Leptochiton Gray. The record of articulate valves in fossil Polyplacophora is rare and requires exceptional preservational conditions. Leptochiton sp. is associated with well preserved bryozoans, brachiopods, asterozoan echinoids, and serpulids, among other organisms that inhabited hard substrates in normal marine conditions, and probably lived attached to the side walls of an incised valley eroded in Cretaceous sediments. The well-preserved fossils were probably removed from their attachment site during storm events and, after a short transportation, rapidly buried within the early Eocene valley-fill deposits. The fossil-bearing beds are included in the Telm 2 or Acantilados Allomember of the La Meseta Formation.

Givetian species of Chinese brachiopods previously assigned to the genus Spinatrypa or Spinatrypina reveal an internal structure characteristic of other species referred to the Eifelian genus Kerpina and the cosmopolitan Frasnian genus lowatrypa. Serial sections clarify the nature of the Middle Devonian Chinese species, which are described here as a new genus, Invertina (type species, Atrypa aspera var. sinensis Kayser, 1883). The internal structure of the Late Devonian type species of Iowatrypa, Atrypa owenensis Webster, 1921, is illustrated for the first time for comparison. These three genera, as well as three other genera, are referred to a new Devonian (Emsian-Frasnian) subfamily, the Invertininae, allocated to the family Atrypidae.

Trilobites of this suborder from Europe and North America have not been studied in detail, in contrast to the attention given to relationships within the orders Agnostida and Ptychopariina. The basis of the Corynexochina is the type species of Corynexochus from the middle Cambrian of Sweden. The type material redescribed here is only the cranidium, and is inadequate for diagnosis of the genus. A species attributed to this genus occurring in the Cambrian of southern France is represented by entire dorsal exoskeletons and is urgently in need of redescription. Similar material is recorded in northern Spain. Both complete exoskeletons and growth stages of Corynexochina have been described from Cambrian strata in Russia, Australia, Morocco and China, showing the wide geographical range and varied morphology of the Suborder. The type species of two genera from boulders of middle Cambrian age found in Quebec, Canada, are redescribed from exceptionally well preserved, though small, specimens. They appear to represent a distinct group related to some of the Zacanthoididae. Families of Corynexochina are inadequately discriminated one from another, so that a family name can only be used with question. Until this is remedied, diagnosis of a new group is not possible.

The lower-middle Hetang Formation (Cambrian Stage 2–3) deposited in slope-basinal facies in South China is well known for its preservation of the earliest articulated sponge fossils, providing an important taphonomic window into the Cambrian Explosion. However, the Hetang Formation also hosts a number of problematic animal fossils that have not been systematically described. This omission results in an incomplete picture of the Hetang biota and limits its contribution to the understanding of the early evolution of animals. Here we describe a new animal taxon, Cambrowania ovata Tang and Xiao, new genus new species, from the middle Hetang Formation in the Lantian area of southern Anhui Province, South China. Specimens are preserved as carbonaceous compressions, although some are secondarily mineralized. A comprehensive analysis using reflected light microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro-CT reveals that the new species is characterized by a spheroidal to fusoidal truss-like structure consisting of rafter-like crossbars, some of which are secondarily baritized and may have been internally hollow. Some specimens have aperture-like structures that are broadly similar to oscula of sponges, whereas others show evidence of a medial split reminiscent of gaping carapaces. While the phylogenetic affinity of Cambrowania ovata Tang and Xiao, n. gen. n. sp. remains problematic, we propose that it may represent carapaces of bivalved arthropods or more likely sponges in early life stages. Along with other problematic metazoan fossils such as hyolithids and sphenothallids, Cambrowania ovata Tang and Xiao, n. gen. n. sp. adds to the diversity of the sponge-dominated Hetang biota in an early Cambrian deepwater slope-basinal environment.

UUID: http://zoobank.org/44de9472-7e3f-42d1-9554-7b3434df91d9

The Clypeastroid echinoid Fibularia texana (Twitchell) has been reported in the literature from only two localities. Twitchell (Clark and Twitchell, 1915) reported that the holotype was collected by T. H. Aldrich from an unspecified locality in Lee County, Texas, from the “Lower Claiborne,” Middle Eocene. Cooke (1942, 1959) reported F. texana from the Weches Formation, lower Claiborne, in San Augustine County, Texas (see Eargle, 1968, for stratigraphic nomenclature). He intimated that the type occurrence in Lee County was also from the Weches Formation. I have recently collected F. texana from the fossiliferous Cook Mountain (upper Claiborne) deposits exposed along Elm Creek in Lee County. Evidence is presented to show that Aldrich's original collection was from Cook Mountain exposures along Elm Creek, and this is designated as the type locality.

A large-diameter coring device was designed to recover plant litter in fluvial sediments as part of a taphonomic study of plant deposition in a modern river system. The corer was used to retrieve unconsolidated sediments from shallow (< 1.5 m) water, either from a boat or from the riverbank, and was designed to be transportable for use in remote reaches of tropical rivers. The device is operable by a single person, easily repaired, and rugged.

Colonial rugose corals are uncommon in Pennsylvanian rocks in North America and until now the only massive form known from rocks of this age south of the Arctic is an undescribed species of Petalaxis reported by Sutherland (1985) from Morrowan rocks in Oklahoma, Texas, and New Mexico. This report concerns a second species of Petalaxis recovered from Desmoinesian rocks immediately west of Death Valley, California. Although only a single colony has been found, it is profoundly different from all other described species of this genus and is significant from the standpoint of its presence during a very long time span when there was an apparent dearth of massive rugose corals in most of North America.

Solitary species of Heliophyllum are the most common form of the genus but branching and massive colonies do occur, especially in Middle Devonian strata of eastern North America. Heliophyllum delicatum n. sp. offsets laterally and has a dendroid, broad bushy growth form. The species is known only from western and west-central New York and appears to be limited to the lower part of the Deep Run Shale Member of the Moscow Formation (middle Givetian); specimens are common within this restricted geographic and stratigraphic range. The skeleton of H. delicatum was poorly designed for the common coral environments of the Devonian, but seems to have been well adapted to muddy, carbonate-poor conditions where its thin skeletal elements required less calcium carbonate and its unsupported branches were not subject to vigorous water movement.

Heliophyllum stewarti n. sp. is based on a single specimen from the Tenmile Creek Dolomite (middle Givetian) in northwestern Ohio. The colony is phaceloid but each branch is an astreoid cluster without walls between individual corallites. In addition, the apparent protocorallite is turbinate with a larger diameter than any of the ceratoid offsets although offset lengths are several times that of the protocorallite.

The Actinocrinitidae were among the most abundant crinoids worldwide during the Lower Mississippian. Recent systematic revisions of the family allow a revised genus- and species-level understanding of these crinoids globally and a more precise means by which to understand the temporal and facies distribution of genera and species in this important Mississippian family. Two genera with a total of five species of Actinocrinitidae (and five additional forms left in open nomenclature) are recognized from the Fort Payne Formation, including Actinocrinites jugosus (Hall, 1859), Actinocrinites spp. indeterminate, Thinocrinus gibsoni (Miller and Gurley, 1893), Thinocrinus lowei (Hall, 1858), Thinocrinus probolos (Ausich and Kammer, 1991), Thinocrinus akanthos new species, Thinocrinus sp. aff. T. gibsoni, Thinocrinus spp. indeterminate, and two taxa recognized as only Actinocrinitidae genus and species indeterminate. Actinocrinites tripus Ehlers and Kesling, 1963 is recognized as a junior synonym of Thinocrinus gibsoni. Thinocrinus, rather than Actinocrinites as previously thought, is the dominant Fort Payne Formation actinocrinitid. Fort Payne Formation carbonate buildup facies (wackestone buildups and crinoidal packstone buildups) each have characteristic species of Thinocrinus. Actinocrinites is relatively rare in the Fort Payne Formation, but occurs preferentially in crinoidal packstone buildups.

Recently discovered specimens of the marsupial Herpetotherium merriami (Stock and Furlong, 1922) from the John Day Formation, Oregon, are described. The species was previously known only from a single (type) specimen. These additional specimens have allowed for a revised diagnosis of the species based on the presence of an additional stylar cusp on the upper molars, as well as the relative size of the stylar cusps. This new material also allows for an examination of the variability within the species and establishes a time range for the species, which extends through most of the Arikareean (late Oligocene: Ar1–Ar3: late Rupelian-Aquitanian). Herpetotherium merriami is distinct within the genus because it is among the larger of the species, but one of the latest occurring, whereas the general pattern of the genus is a reduction in size through time.

Bairdiid ostracodes are commonly present in the Pennsylvanian marine zones in the Appalachian basin. Thirty-one taxa are recognized representing the genera Bairdia McCoy, 1844; Orthobairdia Sohn, 1960; Cryptobairdia Sohn, 1960; Rectobairdia Sohn, 1960; Bairdiolites Croneis and Gale, 1939; and Bairdiacypris Bradfield, 1935. Two questionable bairdiid genera, Entmema new genus and Hastacypris Croneis and Gutke, 1939, are included. Seven new taxa, Bairdia cuspidis, Rectobairdia absidata, R. apiculata, R. levis, R. sohni, Entmena distenta, and Hastacypris acutula, are described. Fabalicypris Cooper, 1946, is considered a junior synonym of Bairdiacypris Bradfield, 1935.

The diversity of bairdiids is significantly lower in the Appalachian basin than in the Eastern Interior and Western Interior basins.