Find research datasets worth reusing

opencc-zeroJun 2020View details →

A new Changhsingian (Lopingian) brachiopod fauna of the shallow-water clastic-shelf facies from Fujian Province, southeastern China

Although much attention has been paid to Changhsingian brachiopods in South China, there are only two Chinese studies, published in 1979 and 1990, on Changhsingian brachiopods from the southeastern part of South China. Based on systematically collected fossil material, this paper describes and quantitatively analyses a Changhsingian brachiopod fauna from the Luokeng Formation at the Hongtian section, Fujian Province, southeastern China, for the first time. Among the brachiopods (30 species in 18 genera) described and illustrated,Cathaysia yongdingensis Liao and an endemic genus of South China (Qinglongia) are reported in English for the first time. Two new species,Neochonetes(Sommeriella)longaand Neochonetes(Sommeriella)transversa,are also proposed. The Hongtian fauna is mainly composed of Cathaysia (29.4%),Neochonetes (19.3%), Linoproductus(13.5%), Orthothetina(11.7%), and is correlated with the brachiopod fauna from the lower part of the Luokeng Formation in Fujian Province.

opencc-zeroNov 2020View details →

The names don't matter but the numbers do: searching for stability in Carboniferous brachiopod paleocommunities from the North American Midcontinent

A key question in paleoecology and macroevolution is whether assemblages of species (paleocommunities) are persistent entities that endure over millions of years. Whilst community turnover in the face of abiotic change is the presumed norm, paleocommunities have been shown to persist for long time periods and regardless of environmental disruption. It remains an open question however, as to what processes allow for this. We investigate these questions by analyzing the Carboniferous brachiopod paleocommunities from the Midcontinent of North America. These diverse communities were subjected to repeated and geologically rapid changes in sea level. Using a suite of statistical techniques, we characterize the nature and scope of changes in these paleocommunities over time. We find that, at the paleocommunity scale, there is no evidence for obdurate ecological stasis, with fluctuations in both taxonomic composition and the associated abundance of taxa. However, at a higher ecological scale, stability is manifest, as diversity patterns remain stable across time, with a consistent number of species that can exist in any given paleocommunity. This suggests ecological rules such as taxon packing are in effect, resulting in a form of ecological stability even in the face of constant disequilibrium, and parallels ecological patterns of disruption and recovery previously observed for invertebrate communities from modern marine systems. Based on these results, we advocate for consideration of different hierarchical entities and scales when interpreting the ecological dynamics of fossil assemblages, as focusing exclusively on changes in taxon identity/abundance or diversity levels can lead to very different results.

opencc-zeroDec 2018View details →

Data from: Cambrian rhynchonelliform nisusioid brachiopods: phylogeny and distribution

A comprehensive review and phylogenetic analysis of genera and species presently assigned to the rhynchonelliform superfamily Nisusioidea and family Nisusiidae suggests that this short-lived but important group of brachiopods first appeared in peri-Gondwana during the second half of the Cambrian Series 2, before going extinct by the end of Drumian time. Nisusiides achieved their maximum morphological disparity and geographical distribution during Wuliuan age, and most likely Laurentia was the major center of dispersal. The new phylogenetic analysis suggests an early separation between the lineages of spinose and non-spinose nisusiids. The non-spinose nisusiids probably evolved in Laurentia by the end of Cambrian Series 4. The new nisusiid genus Bellistrophia is described. The new species Nisusia multicostata represents the first documented rhynchonelliform (kutorginide) brachiopod from the Miaolingian (Drumian) of Alborz Mountains.

opencc-zeroDec 2016View details →

Data from: Ecology, biofacies, biogeography and systematics of micromorphic lingulate brachiopods from the Ordovician (Darriwilian–Sandbian) of south-central China

Ordovician (Darriwilian to Sandbian) micromorphic linguliform lingulate brachiopods are described from the Guniutan Formation at the Fenxiang section in Hubei province, and the Maocaopu and Cili sections in Hunan province of south-central China, situated on the Yangtze Platform. A total of 7560 specimens from 155 limestone samples (within the interval of Lenodus variabilis – Pygodus anserinus biozones) are assigned to 22 species, representing a low taxonomic diversity and low abundance fauna. The fauna is dominated by the Acrotretoidea, mainly species of the Torynelasmatidae, with Torynelasma the most abundant (more than 40% of total number of specimens), along with the Eoconulidae and Eoconulus (18% of total) representing the second most common forms. Species of the Ephippelasmatidae are also common (16% of total) diverse, and include representatives of Myotreta and Numericoma, as well as Ephippelasma, whereas species of the Scaphelasmatidae are somewhat less common (13% of total). All three investigated sections represent outer shelf environments, but the Maocaopu section is situated in a relatively deeper position, in proximity of the south-eastern outer margin of the Upper Yangtze Platform, close to its boundary with the Jiangnan Slope. A quantitative analysis of the relative abundance data was carried out in order to investigate the biofacies distribution of the micromorphic brachiopod communities across the Yangtze Platform, something that has not been attempted before with Palaeozoic linguliforms. Six lingulate microbrachiopod communities could be recognized in the sections. The major biofacies shift, which occurred in the Cili section in the upper part of the Microzarkodina ozarkodella Zone, at the time of the onset and initial rise of the Mid Darriwilian Carbon Isotope Excursion (MDICE) suggests that these biofacies may have been depth controlled.

opencc-zeroDec 2014View details →

Data from: Himalayan Cambrian brachiopods

A synoptic analysis of previously published material and new finds reveals that Himalayan Cambrian brachiopods can be referred to 18 genera, of which 17 are considered herein. These contain 20 taxa assigned to species, of which five are new: Eohadrotreta haydeni, Aphelotreta khemangarensis, Hadrotreta timchristiorum, Prototreta? sumnaensis and Amictocracens? brocki. Well-preserved topotype material from the classic Parahio Valley section is described for three species that have not previously been illustrated photographically. A biostratigraphical scheme based on Cambrian brachiopod occurrence is integrated with that recently proposed for trilobites. Regional correlations based on shared taxa within and across Himalayan lithotectonic belts demonstrate that erosion of Cambrian rocks in the Kurgiakh orogeny in the Parahio Valley removed little of the Parahio Formation and that all of the fossil-bearing lithotectonic zones share similar late early Cambrian brachiopods, suggesting regional faunal continuity at the time. Palaeobiogeographical analysis of the Cambrian brachiopod faunas from the Himalaya shows that they occupied a marginal position of the Australasian segment of Gondwana.

opencc-zeroDec 2017View details →

Data from: Linguliform brachiopods across a Cambrian–Ordovician (Furongian–Early Ordovician) biomere boundary: the Sunwaptan/Skullrockian North American stage boundary in the Wilberns and Tanyard Formations of central Texas

The Cambrian-Ordovician Diversity Plateau, between the Cambrian Explosion and the Ordovician Radiation, is punctuated by a series of well-documented Laurentian trilobite extinction events. These events define the bounding surfaces of trilobite "biomeres" that correspond to North American stages, including those of the Sunwaptan and Skullrockian. Trilobites show a consistent pattern of recovery across these boundaries, and commonly each extinction and replacement of taxa is interpreted as a single event as changing environmental conditions spurred shoreward migration of shelf or oceanic faunas that displaced established cratonic faunas. Linguliform brachiopods are also abundant in strata of this interval, and we investigate their stratigraphic distribution across the Sunwaptan–Skullrockian Stage boundary in Texas through high-resolution stratigraphic sampling of subtidal sediments. We document complete genus- and species-level turnover of the linguliform brachiopod fauna coincident with trilobite extinction events, suggesting that these brachiopods were affected by the same factors that affected trilobites. The Skullrockian replacement fauna was cosmopolitan, with ties to Gondwana and Kazakhstan and to the Laurentian shelf environment. The timing of appearances of taxa suggests that the faunal migration onto the Laurentian shelf came from elsewhere during a transgression. The disappearance of the Sunwaptan fauna and the arrival of the Skullrockian fauna are distinct events. We suggest that "biomere" events may be complex, and the cause of the extinction is not necessarily the same event that facilitates the appearance of a replacement fauna. We describe one new species, Schizambon langei.

opencc-zeroDec 2015View details →

Data from: A combined morphometric and phylogenetic revision of the late Ordovician brachiopod genera Eochonetes and Thaerodonta

Systematic revision of the Late Ordovician brachiopod genera Eochonetes Reed, 1917 and Thaerodonta Wang, 1949 was conducted utilizing specimen-based morphometric and species-level phylogenetic analyses. Previous studies had recognized Thaerodonta and Eochonetes as either distinct taxonomic entities or synonyms. New multivariate and phylogenetic analyses confirm the synonymy of Thaerodonta with Eochonetes and provide a framework to assess evolutionary and ecological patterns within the clade. Multivariate analyses were employed to delineate species in morphospace and provided information on potential species relationships. Phylogenetic analysis was used to produce an evolutionary framework for taxonomic revision and identify character evolution within the clade. Most species previously assigned to Thaerodonta are transferred to Eochonetes, and three others are excluded from Eochonetes and provisionally referred to other sowerbyellid genera. Three new species (Eochonetes maearum new species, E. voldemortus new species, E. minerva new species) are described, one species (Leptaena saxea Sardeson, 1892) is synonymized with E. recedens Sardeson, 1892, and one subspecies (Thaerodonta mucronata scabra Howe, 1965) is rejected. This study demonstrates that a combination of complementary approaches and data types has the potential to advance interpretations beyond analyses confined to single analytical tools. Specifically, multivariate analyses provide constraints on species boundaries, whereas species-level phylogenetic analyses provide frameworks to examine morphological, ecological, and biogeographic evolution within a clade.

opencc-zeroDec 2011View details →

Data from: Molecular phylogeny of rhynchonellide articulate brachiopods (Brachiopoda, Rhynchonellida)

We present here the first report based on phylogenetic analyses of small subunit (SSU/18S) and large subunit (LSU/28S) ribosomal DNA (rDNA) sequences from a wider-than-token sample of rhynchonellide articulate brachiopods, with data from 11 of ∼20 extant genera (12 species) belonging to all four extant superfamilies. Data exploration by network and saturation analyses shows that the molecular sequence data are free from major aberrations and are suitable for phylogenetic reconstruction despite the presence of large deletions in four SSU rDNA sequences. Although molecular sequence analyses cannot directly illuminate the systematics of fossils, the independent, genealogical evidence and phylogenetic inferences about extant forms that they make possible are highly relevant to paleontological systematics because they highlight the limitations of evolutionary inference from morphology. Parsimony, distance, maximum likelihood (no clock) and Bayesian (relaxed-clock) analyses all find a tree topology that disagrees strongly with the existing superfamily classification. All tested phylogenetic reconstructions agree that the taxa analyzed fall into three clades designated A1, A2, and B that reflect two major divergence events. The relaxed-clock analysis indicates that clades A and B diverged in the Paleozoic, while clades A1 and A2 reflect Permo-Triassic (and later) events. Morphological homoplasy and possible gene co-option are suggested as the main sources for the discord between the morpho-classification, the results of cladistic analyses of morphology, and the relationships reconstructed from molecular sequences. The origin, function and evolutionary implications of the deletion-bearing rhynchonellide SSU rDNA sequences are briefly discussed in relation to pseudogenes and concerted evolution in the rDNA genomic region.

opencc-zeroDec 2013View details →

Data from: Phylogenetic signal in extinction selectivity in Devonian terebratulide brachiopods

Determining which biological traits affect taxonomic durations is critical for explaining macroevolutionary patterns. Two approaches are commonly used to investigate the associations between traits and durations and/or extinction and origination rates: analyses of taxonomic occurrence patterns in the fossil record and comparative phylogenetic analyses, predominantly of extant taxa. By capitalizing upon the empirical record of past extinctions, paleontological data avoid some of the limitations of existing methods for inferring extinction and origination rates from molecular phylogenies. However, most paleontological studies of extinction selectivity have ignored phylogenetic relationships because there is a dearth of phylogenetic hypotheses for diverse non-vertebrate higher taxa in the fossil record. This omission inflates the degrees of freedom in statistical analyses and leaves open the possibility that observed associations are indirect, reflecting shared evolutionary history rather than the direct influence of particular traits on durations. Here we investigate global patterns of extinction selectivity in Devonian terebratulide brachiopods and compare the results of taxonomic vs. phylogenetic approaches. Regression models that assume independence among taxa provide support for a positive association between geographic range size and genus duration but do not indicate an association between body size and genus duration. Brownian motion models of trait evolution identify significant similarities in body size, range size, and duration among closely related terebratulide genera. We use phylogenetic regression to account for shared evolutionary history and find support for a significant positive association between range size and duration among terebratulides that is also phylogenetically structured. The estimated range size–duration relationship is moderately weaker in the phylogenetic analysis due to the down-weighting of closely related genera that were both broadly distributed and long lived; however, this change in slope is not statistically significant. These results provide evidence for the phylogenetic conservatism of organismal and emergent traits, yet also the general phylogenetic independence of the relationship between range size and duration.

opennotspecifiedDec 2013View details →

FIGURE 4 in New paedomorphic brachiopods from the abyssal zone of the north-eastern Pacific Ocean

FIGURE 4. Simpliciforma profunda Bitner & Zezina gen. et sp. nov., Clarion-Clipperton Zone, north-eastern Pacific; A, dorsal view of complete specimen, paratype, XI-52-24/2, Stn 27, depth 4850 m; B–D, dorsal valve, inner view and enlargement of the lophophore (C, D), paratype, XI-52-24/3, Stn 185–199, 4580 m; E, F, dorsal view of complete specimen, and enlargement of the umbonal part to show details of the beak, holotype, XI-52-24/1, Stn 217, 4680 m; G–I, dorsal view of complete specimen, and enlargement of the umbonal part, slightly tilted, to show details of the beak (H) and of the shell surface to show distinct growth lines (I), paratype, XI-52-24/4, Stn 185-199, 4580 m.

opennotspecifiedDec 2013View details →

FIGURE 3 in New paedomorphic brachiopods from the abyssal zone of the north-eastern Pacific Ocean

FIGURE 3. Oceanithyris juveniformis Bitner & Zezina gen. et sp. nov., Clarion-Clipperton Zone, north-eastern Pacific; A, dorsal view of young complete specimen, XI-52-23/5, Stn 41, 4790 m; B–E, ventral, dorsal and lateral views of complete specimen, and enlargement of the umbonal part (E) to show details of the beak and the rough surface anterior to the protegular node and fine striae, holotype, XI-52-23/1, Stn 41, 4790 m; F–H, dorsal and posterior views of complete specimen, and enlargement of the umbonal part (H) to show details of the beak and the rough surface anterior to the protegular node, paratype, XI-52-23/2, Stn 217, 4680 m; I–L, dorsal valve, inner views with preserved lophophore and after its removal, and enlargements of posterior part (K, L) to show details of cardinalia, paratype, XI-52-23/3, Stn 217, 4680 m; M–O, ventral valve, inner view (M), and enlargement of posterior part (N) and tilted view (O) to show rudimentary deltidial plates, hooked teeth and step-like thickening of the shell, paratype, XI-52-23/4, Stn 27, depth 4850 m.

opennotspecifiedDec 2013View details →

FIGURE 2 in New paedomorphic brachiopods from the abyssal zone of the north-eastern Pacific Ocean

FIGURE 2. Manganese nodules with attached brachiopods, Clarion-Clipperton Zone, Pacific; A, Pelagodiscus atlanticus (King, 1868), Stn 21, 4790 m; B, Oceanithyris juveniformis Bitner & Zezina gen. et sp. nov., Stn 197, 4580 m.

FIGURE 10 in Revision of the brachiopod genus Amphithyris (Rhynchonelliformea: Platidiidae) with descriptions of two new species

FIGURE 10. Geographical distribution of the genus Amphithyris. A. seminula (■); A. buckmani (●); A. hallettensis (▲); A. richardsonae (+); A. parva (x); A. cavernicola n. sp. (*); A. comitodentis n. sp. (ο). Note that both collecting stations for A. hallettensis give only the longitudinal position, as they were found at lower latitudes in Antarctic waters not shown in the map.

FIGURE 8. Amphithyris cavernicola n in Revision of the brachiopod genus Amphithyris (Rhynchonelliformea: Platidiidae) with descriptions of two new species

FIGURE 8. Amphithyris cavernicola n. sp., Coral Sea, Australia; A. Paratype ZMB Bra 2185. Lateral view showing ventribiconvex shells. B. Paratype QM G333508. Smooth dorsal valve exterior. C–E. Holotype QM G333507. C. Dorsal valve interior. D. Detail of punctae. E. Close-up of amphithyrid foramen. F. Paratype ZMB Bra 2175. Dorsal valve interior showing (dried) schizolophous lophophore and gonads. Scale bars: A, B, C, E and F = 200µm; D = 50µm.

FIGURE 9. Amphithyris cavernicola n in Revision of the brachiopod genus Amphithyris (Rhynchonelliformea: Platidiidae) with descriptions of two new species

FIGURE 9. Amphithyris cavernicola n. sp., Coral Sea, Australia; A–C. Paratype ZMB Bra 2180. A. Ventral valve interior, showing low median septum and muscle impressions visible. B. Close-up of posterior region of ventral valve interior. C. Lateral view of ventral median septum and hinge teeth. D. Holotype QM G333507. Ventral valve exterior, with tubercles. E. Paratype ZMB Bra 2178. Broken ventral valve, exterior view, exposing secondary shell layer. F–H. Paratype ZMB Bra 2179. F. Protegulum with one middle and two lateral ridges. G–H. Tubercles on ventral valve exterior. I–L. Paratype ZMB Bra 2187. SEM backscatter images in environmental mode. I. Ventral valve exterior showing weak capillae. J–L. Ventral valve exterior showing exterior end of brushes with tubercles. Scale bars: A–E = 200µm; F, H and J = 50µm; G, I, K, L = 10µm.

FIGURE 5 in Revision of the brachiopod genus Amphithyris (Rhynchonelliformea: Platidiidae) with descriptions of two new species

FIGURE 5. Amphithyris seminula (Philippi, 1836). Sicily, Mediterranean Sea. A–B. Paralectotype ZMB Bra 1675. A. Dorsal valve interior with low median septum. B. Lateral view of dorsal valve. C–F. Lectotype ZMB Bra 2146. C. Close-up of dorsal valve interior with short socket ridges. D. Ventral valve interior. E. Close-up of ventral valve interior showing beak-like hinge teeth. F. Lateral view of ventral valve, showing smooth surface. Scale bars = 200µm.

FIGURE 7. Amphithyris cavernicola n in Revision of the brachiopod genus Amphithyris (Rhynchonelliformea: Platidiidae) with descriptions of two new species

FIGURE 7. Amphithyris cavernicola n. sp., Coral Sea, Australia; A. Paratype ZMB Bra 2186 Ventral view showing attachment to coral rock; B. Paratype ZMB Bra 2175. Ventral view, showing schizolophous lophophore (L) and gonads (G). Scale bar = 200µm.