Ediacaran fronds at Spaniard's Bay on the Avalon Peninsula of Newfoundland exhibit exquisite, three-dimensional preservation with morphological features less than 0.05 mm in width visible on the best preserved specimens. Most of the nearly 100 specimens are juvenile rangeomorphs, an extinct Ediacaran clade that numerically dominated the early evolution of complex multicellular life. Spaniard's Bay rangeomorphs are characterized by cm-scale architectural elements exhibiting self-similar branching over several fractal scales that were used as modules in construction of larger structures. Four taxa of rangeomorph fronds are present – Avalofractus abaculus n. gen. et sp., Beothukis mistakensis Brasier and Antcliffe, Trepassia wardae (Narbonne and Gehling), and Charnia cf. C. masoni Ford. All of these taxa exhibit an alternate array of primary rangeomorph branches that pass off a central stalk or furrow that marks the midline of the petalodium. Avalofractus is remarkably self similar over at least four fractal scales, with each scale represented by double-sided rangeomorph elements that were constrained only at their attachment point with the higher-order branch and thus were free to rotate and pivot relative to other branches. Beothukis is similar in organization, but its primary branches show only one side of a typical rangeomorph element, probably due to longitudinal branch folding, and the position of the individual branches was moderately constrained. Trepassia shows only single-sided branches with both primary and secondary branches emanating from a central stalk or furrow; primary branches were capable of minor pivoting as reflected in bundles of secondary branches. Charnia shows only single-sided primary branches that branch from a zigzag central furrow and that were firmly constrained relative to each. This sequence provides a developmental linkage between Rangea-type and Charnia-type rangeomorphs. Avalonian assemblages show a wide array of rangeomorph constructions, but later Ediacaran assemblages contain a lower diversity of rangeomorphs represented mainly by well-constrained forms.

Assessment of ontogenetic and geographic variation can have substantial influence on species delimitation and thereby on perceived patterns of species-level morphological variation and diversity in space and time. Here we describe the ontogeny and intraspecific variation of the early Cambrian trilobite, Zacanthopsis palmeri n. sp., based on silicified material from east-central Nevada, USA. Zacanthopsis palmeri is the oldest documented Cambrian corynexochine to shift from possessing a fused rostal-hypostomal plate to a functional hypostomal suture in mature specimens during ontogeny. Six geographically distinct samples of mature Z. palmeri from a single silicified limestone bed traceable over tens of kilometers in east-central Nevada permit exploration of geographic variation within this species using geometric morphometric methods. No one sample encompasses all of the shape variation expressed by Z. palmeri and several geographically segregated samples show some degree of morphological separation in pairwise comparison. Nonetheless, these samples are not qualitatively or quantitatively different from one another when all samples are taken into account. The degree of variation within Z. palmeri is similar in magnitude to the differences between other species in the genus known from much less material.

Upper Ordovician radiolarians are described from limestone within the Malongulli Formation in the Cliefden Caves area using revised systematics. Eight genera and 12 species are described, including the following four new species: Protoceratoikiscum crossingi, Haplotaeniatum ovatum, Haplotaeniatum prolatum, and Borisella dunhilli, and two new combinations, Borisella subulata and Haplotaeniatum spongium. All samples are dominated by Kalimnasphaera maculosa, B. subulata, and Palaeoephippium octaramosum with lesser abundances of Haplotaeniaum spp. and Inanigutta complanata, and rare occurrences of Protoceratoikicsum spp. The rare species Etymalbaillella yennienii is reported for the first time outside of China. The Malongulli Formation is upper Eastonian through lower Bolindian (Katian global stage) based on graptolite and conodont biostratigraphy. From a stratigraphic standpoint, the limestone intervals sampled appear to represent two or possibly three stratigraphically separate intervals within the Malongulli Formation. Conodonts recovered from Coppermine Creek, Angullong/Belubula, and Gleesons Creek localities occur in the lower and middle parts of the formation and fall within one conodont zone, the O. velicuspis Zone. The stratigraphic position of the limestone at the Sugarloaf Creek locality is higher, possibly as high as lower Bolindian, based on proximity to the top of the formation where Bolindian graptolites have been recovered. Despite the different stratigraphic positions of the limestones, the radiolarians contained within are essentially the same fauna, barring some differences in relative abundance in Haplotaeniatum and Palaeoephippium. The Malongulli fauna is discussed with respect to other Upper Ordovician faunas, most notably those from siliceous facies in the eastern Lachlan Orogen and from the Hanson Creek Formation of Nevada, U.S. The radiolarian species occur across different depositional environments and from a range of geographically widespread localities, which bodes well for them being recognized as biostratigraphically important faunal markers with correlation potential within the Katian.

Oyenaster oblidus, Ocalaster timucum, and Ocalaster seloyi are new genera and species of the family Goniasteridae (Asteroidea) described from the Eocene Ocala Limestone of Florida. Although the fossil record of asteroids is sketchy, goniasterids appear to have been important contributors to marine communities since at least the Middle Jurassic. Similarities between living goniasterids and their fossil precursors indicate that plesiomorphy and convergence have been important in family history, and as a result, taxonomic interpretation is challenging. Even partial fossil goniasterids are rare, forcing systematists to rely heavily on isolated marginal ossicles, although some authors have expressed the need for caution. Building around three new taxa, we suggest that broader approaches can aid systematic interpretation of all crown-group asteroids. We also suggest that the inevitably idiosyncratic interpretations of marginal-based systematics can be partially tested using blind evaluations.

Very few macroscopic soft-bodied Ediacaran fossils are hosted in carbonates; most of them are preserved as casts and molds in siliciclastic rocks or as carbonaceous compressions in black shales. This taphonomic bias limits our capability to fully understand the diversity and paleoecology of macroscopic Ediacaran life forms. Previous reports have shown that the upper Ediacaran Dengying Formation in South China and Khatyspyt Formation in Siberia contain macroscopic soft-bodied fossils preserved in bituminous limestone; thus they have the potential to expand our knowledge about the Ediacaran biosphere. However, the biogenecity of the Dengying fossils described in Xiao et al. (2005) has been questioned. In this paper, we provide additional material and arguments in support of the biogenecity of these fossils, which are formally described as Yangtziramulus zhangi new genus and species. Yangtziramulus zhangi consists of a branching system with a central axis and tubes on both sides. The tubes appear to be distally open. Yangtziramulus zhangi is interpreted as a flat-lying benthic organism, as indicated by the mutual avoidance relationship among densely clustered individuals. Yangtziramulus zhangi finds few morphological analogs among modern organisms, but it is broadly similar to several macroscopic Ediacaran forms. Its morphological and ecological complexity is inconsistent with a microbial interpretation. Yangtziramulus zhangi is typically covered by a thin veneer of fine-grained silts, suggesting that it was probably smothered and killed by an episodic flux of silty sediments (event deposits). Its tube walls are replaced with early diagenetic calcspars.

Family Orthothecidae Sysoev, 1958 is herein emended to encompass only hyoliths that possess a very shallow longitudinal ventral concavity and a tightly rounded dorsum, resulting in a near-triangular to only slightly kidney-shaped cross section. OrthothecaNovak, 1886 is restricted to orthothecids that possess longitudinal ornamentation on the dorsum, with Cryptocaris suavisBarrande, 1872 now recognized as the type species of that genus. Based on the revised generic concept, orthothecids from the Lower Devonian (Emsian) Shriver Chert of northeastern Pennsylvania are here included within the genus as Orthotheca shriveri n. sp., making this the first occurrence of the genus in North America. The Orthothecida were a group of sessile, benthic hyoliths that ranged from Early Cambrian to Early Devonian. Their life habit appeared to have included filter-feeding. Their ability to retract the operculum into the shell when closed probably aided in preventing sediment influx, and the ventral furrow may have been an adaptation to differing degrees of firmness of the underlying substrate. Despite faunal linkages between the Devonian paleocontinents, the majority of orthothecid genera seem to be largely restricted to their type areas, although Orthotheca documented herein has eroded slightly their endemic character.

Two brachiopod species of two of the earliest rhynchonelliformean families are described from one of the first studied Ordovician fossiliferous localities of northwestern Argentina. One is a new species of the family Euorthisinidae (Orthida, Plectorthoidea), Notorthisina musculosa Villas and Herrera. It displays peculiar features not observed in the family before, as well as a combination of internal and external features previously considered diagnostic of different genera, leading to emendment of the familial and generic diagnoses. Its dorsal muscle field, best impressed in large specimens, resembles that of Kvania Havlíček (Nanorthidae) in having four scars arranged radially. This feature reinforces the phylogenetic proximity of Kvania to the euorthisinids. The second studied species, Nanorthis bifurcata Harrington, has not been revised since its superficial description in 1937–1938, its type having been lost. Its description herein, based on a new collection from its type locality, allows a better knowledge of the group and helps clarify its supra-familial assignment.

Within the Soom Shale Lagerstätte of South Africa (Upper Ordovician, Hirnantian), two brachiopod taxa preserve traces of organic tissue. In Trematis, presumed bands of periostracum are preserved on the flanks of the pedicle notch, and clay mineral casts of the pedicle are preserved in many specimens of Kosoidea. Both these genera are organophosphatic-shelled Linguliformea, together with a third genus identified as Plectoglossa. A fourth brachiopod taxon in the fauna belongs within the calcitic-shelled Rhynchonelliformea (Plectothyrella). Kosoidea cedarbergensis is a new species of discinoidean.

Investigations of recently cracked concretions from the Carboniferous Montceau-les-Mines, France, Lagerstätte led to the recognition of two new malacostracan Crustacea: a palaeophreatoicid isopod, Sottyella montcellensis n. g., n. sp., and a gorgonophontid stomatopod, Chabardella spinosa n. g., n. sp. The occurrence of the palaeophreatoicid isopod Palaeocrangon is discussed, and a new specimen of the syncarid Palaeocaris secretanae allows us to clarify some of its morphological characters. The recognition of these taxa increases the faunal inventory of malacostracans in the Montceau-les-Mines Lagerstätte.