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The reefs of the Vasalemma Formation, late Sandbian, Late Ordovician, of northern Estonia contain an exceptional rich and abundant bryozoan fauna. They are an example of contemporaneous bryozoan-rich reefs known from around the world, representing the peak diversification interval of this group during the Ordovician. The global Ordovician bryozoan diversification was associated with a decrease in provinciality, a pattern known from other skeletal marine metazoans of this period. The diversification is associated with climatic cooling and increasing atmospheric and sea water oxygenation. However, the mechanisms that led to the bryozoan diversification are poorly known. Here we estimate the bryozoan richness (α and γ diversity) and turnover (β diversity) at the level of samples, reefs, and formations in the Vasalemma Formation and in contemporaneous reef limestone occurrences of the Baltoscandian region. The resulting richness and turnover values differ among the three observational levels and hence are scale dependent. A consistent pattern with lowest between-reef turnover and relatively high between-sample turnover could be detected, reflecting high small-scale (within reef) heterogeneities in lithology and original bryozoan habitat. This is consistent with published work, in which evidence has been presented for small-scale substrate heterogeneity as the most important diversification driver of the Ordovician brachiopod diversification in the Baltoscandian region. The fact that reefs and their local substrate are strongly organism moderated environments sheds light on the potentially important ecosystem engineering role of organisms, such as bryozoans, for the Ordovician diversification. [ABSTRACT FROM AUTHOR]

The Skyberg Biota is a new early Cambrian Konservat-Lagerstätte, documented from a 7.5-m-thick succession of the Skyberg Member, Ringstranda Formation, in the classical Mjosa area of Norway. It displays a high species diversity and contains: algae; sponges; brachiopods; hyoliths; bivalved arthropods; trilobites; palaeoscolecids and other vermiform organisms; weakly sclerotized fragments of unknown affinity; several tubicolous fossils; the enigmatic genus Lapworthella; and a number of additional problematica together with infrequent trace fossils consisting of burrows and faecal pellets. This novel macro-biota encloses the most diverse fossil assemblage known from the Cambrian Series 2 locally in the Mjosa area, and regionally in Baltoscandia, and currently includes around 50 species of 10 major animal groups and macro-algae. The Skyberg Biota contains taxa previously unknown from Norway, several are new to Baltoscandia and also includes a range of new species. The Skyberg biota offers a rare glimpse into the biodiversity of Baltoscandia just prior to the large faunal turnover at the late-middle Cambrian transition. [ABSTRACT FROM AUTHOR]

This paper presents new arguments that contribute to support the hypothesis about the functional meaning of the commissural asymmetry in the Coniacian (Upper Cretaceous) rhynchonellide Cyclothyris cardiatelia Berrocal-Casero. According to this hypothesis, commissural asymmetry is interpreted as an adaptation to life on soft substrates, which leads to a life position that is oblique and partially sunk in relation to the substrate. The taphonomic compression of one of the shell lobes observed in asymmetrical C. cardiatelia has been compared to the compression found in a symmetrical rhynchonellide in which the compression is located at the frontal part of the shell, supporting the idea of a different life position than in C. cardiatelia. Additionally, the fossil record shows that brachiopods exhibiting external asymmetry usually display the corresponding asymmetry in the brachidium, related to dysfunction or atrophy of one of the lophophore arms. Observations in extant rhynchonellides show they can live with one arm of the lophophore atrophied or misfunctioning, and even amputated. The applicability of this hypothesis to other cases of commissural asymmetry in rhynchonellides, such as those living in closely packed clusters, reef environments or affected by unidirectional currents, is discussed, considering that the common physiological response to these different palaeoenvironmental scenarios would be a differential use of the arms of the lophophore, in turn affecting commissure plication. This physiological response could explain the origin of obligate asymmetry in other rhynchonellide lineages besides Cyclothyris M´Coy, for instance in Torquirhynchia Childs. Continuous records of both facultative and obligate asymmetrical rhynchonellides along single phyletic lines will be necessary, in order to establish whether this interpretation is a generalized explanation for asymmetrical shells in rhynchonellides. [ABSTRACT FROM AUTHOR]

Five quartzose sandstone slabs hosting small groups or mass associations of Anaconularia anomala are described from the Upper Ordovician Letná Formation in the Prague Basin. The slabs contain from 4 to 59, mutually adjacent or contiguous conulariids ranging from 5 to 89 mm in length and situated on a single bedding plane. Associated with the conulariids are small mudstone intraclasts and other fossils, mostly disarticulated brachiopods and trilobites. All 101 studied conulariid specimens are oriented parallel to bedding and show strong preferential alignment, with the apical ends pointing in the same general direction. Sixteen of the conulariids terminate adapically in a probabe schott and/or exhibit a possible internal schott, while five specimens preserve one or two apertural lappets. The investigated conulariids lived in clumps and were buried catastrophically following alignment by unidirectional currents or flows acting on bodies that may have been leaning in the down–current direction and/or which had their center of mass displaced toward their apical end. Neither these nor 3000 additional specimens of A. anomala from the Sandbian Letná and Zahořany formations show any evidence of clonal budding; however, the hypothesis that clumping resulted from asexual proliferation cannot be ruled out. Finally, the periderm of A. anomala was compaction– resistant and smooth, lacking both corrugation (transverse ribs) and nodes, but whether the angular groove present at the facial midline of casts is a mould of a midline sulcus or of an internal carina remains unclear. [ABSTRACT FROM AUTHOR]

Microscopic perforations in brachiopod shells, such as endopunctae, pseudopunctae, extropunctae, aditicules and epipunctae, have various biological functions. Based on excellently preserved material, aditicules are found to be widely developed in the Fusichonetes and Neochonetes, and setae‐bearing aditicules are shown to exist in rugosochonetid brachiopods for the first time. SEM and Micro‐CT images show that aditicules obliquely insert into the primary layer and are arranged in a single column along the crest of a costellae. The setae are supposed to play a role in triggering the closure of shells by sensing dangers, preventing large particles from entering the inner cavity and helping to increase the water pressure by forming a functional siphon. The SEM and Micro‐CT images also show that papillae are solid cones on the inner surface of the shell, and the density of papillae varies over different regions of the shell surface, and with environment. The variation in density of the papillae is most likely related to diverse functions in the 'filtering system'. In the marginal area, the small and densely spaced papillae can prevent intermediate and fine particles from entering the mantle cavity, whereas the large and sparse papillae in the mid‐valve can trap fine particles. In this study, these two microstructures are interpreted as a sediment 'filtering system' in Fusichonetes and Neochonetes, which is corroborated by the predominant occurrence of these genera in shallow‐water clastic shelves and deep‐water siliceous basins across the Permian–Triassic boundary interval in South China. [ABSTRACT FROM AUTHOR]

Fossils are useful as palaeoenvironmental indicators when evaluated using large occurrence and lithology association data sets and/or functional morphology. However, when functional morphology is invoked on an ad hoc basis there exists a risk of circular reasoning. Performance spaces/landscapes constructed using biomechanical experiments can be used to tie performance to morphology quantitatively. They can be used to estimate fitness and function in specific environments by allowing multiple specific measures of function to be evaluated simultaneously. Absolute performance can be used to constrain palaeoenvironmental interpretations by detecting functional limits. We constructed a performance space with four variables (transport resistance, settling time, settling orientation and respiration potential) relating to hydrodynamic and metabolic variables. We combine new performance data with existing palaeoenvironmental interpretations and associated distributions of brachiopods of the suborder Productidina during the late Carboniferous and early Permian in the North American Midcontinent. Productidines were chosen because they lacked pedicles and relied on body and spine morphology to interact with their environment. Offshore dysoxia‐associated taxa had increased resistance to sinking and proportionally larger lophophores, potentially improving survivorship in low‐oxygen, soft substrate environments. Taxa associated with nearshore and oxygenated offshore environments display a range in performance consistent with a range of conditions, but all had proportionally smaller lophophores. Models that are less stable in high‐velocity flows consistently settle in the correct convex down orientation if entrained, while more stable models did not. Our study suggests that as productidines radiated during the Carboniferous, they also differentiated within the performance space. [ABSTRACT FROM AUTHOR]

Thecideide brachiopods are an anomalous group of invertebrates. In this study, we discuss the evolution of thecideide brachiopods from the Triassic to the Holocene and base our results and conclusions on microstructure and texture measurements gained from electron backscatter diffraction (EBSD). In fossil and Recent thecideide shells, we observe the following mineral units: (1) nanometric to small granules; (2) acicles; (3) fibres; (4) polygonal crystals; and (5) large roundish crystals. We trace for thecideide shells the change of mineral unit characteristics such as morphology, size, orientation, arrangement and distribution pattern. Triassic thecideide shells contain extensive sections formed of fibres interspersed with large, roundish crystals. Upper Cretaceous to Pleistocene thecideide hard tissues consist of a matrix of minute to small grains reinforced by acicles and small polygonal crystals. Recent thecideide species form their shell of mineral units that show a wide range of shapes, sizes and arrangements. We find from Late Triassic to Recent a gradual decrease in mineral unit size, regularity of mineral unit morphology and orientation and the degree of calcite co‐orientation. While crystallite co‐orientation is the highest for fibrous microstructures, it is strikingly low for taxa that form their shell out of nanogranular to acicular mineral units. Our results indicate that Upper Jurassic species represent transitional forms between ancient taxa with fibrous shells and Recent forms that construct their shells of acicles and granules. We attribute the observed changes in microstructure and texture to be an adaptation to a different habitat and lifestyle associated with cementation to hard substrates. [ABSTRACT FROM AUTHOR]

The varied microstructures of brachiopod biominerals represent a robust archive to understand the evolution and adaptations of marine calcifiers in time. Therefore, a detailed study of the shell microstructure of Cambrian to Devonian brachiopods from Iran is here presented. The shell of 38 brachiopod species, representatives of 22 families and nine orders, has been analysed using scanning electron microscope (SEM), and a database has been built, including macro‐ and micro‐morphological features used to characterize the two‐ or three‐layered brachiopod shells. Two main microstructural variants of the secondary layer have been analysed: fibrous and laminar fabrics. The fibrous layer has a fabric comparable to that of recent brachiopods, whereas the laminar fabric is more complex in its structural organization and has no recent analogue. In cross‐section, the laminae are thinner than the fibres, and much less variable in size. There is evidence that taxa with laminar microstructure have diverged from the Billingsellida and then followed a trend implying a decrease in thickness of the laminae. Our linear discriminant analysis (LDA) shows that shell fabric and shell thickness are powerful predictors of shell shapes, which in turn approximate the brachiopod lifestyles and ecological strategies. Taxa with a fibrous fabric are mostly biconvex, whereas the groups with a laminar secondary layer are associated to a variety of shell shapes and lifestyles. Even if the relations between shell fabric and shell thickness remain enigmatic, as well as the metabolic cost they imply, shell fabrics, and the possible structural and mechanical advantages conferred, could have played a role in the evolutionary success of the Strophomenata during the Palaeozoic. [ABSTRACT FROM AUTHOR]

The origin of the Brachiopoda has long been a hotly debated topic, and various models have been proposed following the latest finds of exceptionally preserved material. The lower Cambrian (Stage 3) Heliomedusa orienta from the Chengjiang Konservat‐Lagerstätte, eastern Yunnan of South China, is an important example of exceptional preservation. A wide variety of affinities have been proposed for Heliomedusa, but recently it has been suggested to reside within the mickwitziids, which may form a stem group to the Brachiopoda. Detailed studies of exceptionally preserved Heliomedusa have increased our knowledge of the soft‐part anatomy of this important early brachiopod, but unfortunately, almost nothing is known about its shell structure. Here, we describe new exceptionally preserved specimens from the Chengjiang biota to better reveal both shell structure and ornamentation. Its reticulate–pustulose ornament and tubular structure are reminiscent of traits seen in other mickwitziid brachiopods. In addition, two types of setae can be observed. Apart from the pyritized marginal mantle setae, some tubules are filled with iron oxides, potentially representing thinner and shorter penetrative setae. Both valves of H. orienta appear to have been less mineralized as compared to Mickwitzia monilifera, and the two species differ in diameter and density of tubules and pustules, and in terms of slightly less projected profile of ventral valve with lower umbo posteromedially placed. Although Heliomedusa clearly is closely related to Mickwitzia, their different preservational modes (compacted poorly mineralized/noncompacted mineralized) make detailed comparison difficult; they are provisionally kept as separate genera pending further studies of better‐preserved Chinese material. [ABSTRACT FROM AUTHOR]

A large brachiopod fauna collected through the upper Wanyaoshu Formation (middle Hirnantian), West Yunnan, China displays, for the first time, a vertical transition within the Hirnantia fauna. The inner to mid‐shelf Fardenia–Hirnantia association segues into the deeper water Aegiromena–Anisopleurella association during the Metabolograptus persculptus marine transgression. This transition parallels the pattern apparent in onshore–offshore gradients within the Hirnantian, imitating Walther's Law for facies, instead predicting the seaward transitions between community types within a single transgressive sequence. In addition, large‐sized brachiopods such as Hirnantia and Eostropheodonta become rarer and small‐sized brachiopods, for example, Aegiromena and Anisopleurella more common. It is a rare opportunity to view transformations in community composition and structure within the Hirnantia fauna together with changes in both the size of individuals and populations (from large to small) during the transgression. [ABSTRACT FROM AUTHOR]

The biogeography of Pliensbachian (Early Jurassic) brachiopods in western Tethys is investigated using complementary multivariate tools including metric and non‐metric ordination, additive cluster and bootstrapped spanning network analyses, as well as one‐way analysis of similarity and similarity percentage analysis. All analyses were conducted using the Dice and Simpson similarity indices for presence/absence data on occurrence datasets involving 24 assemblages homogenized at the species level, including (403 taxa) or excluding (210 taxa) species found in only one assemblage. The analyses present a highly consistent biogeographical picture involving three main clusters: the Euro‐Boreal, Mediterranean and Pontic biochores. The brachiopod species typical of the newly defined Pontic biochore are illustrated. The three assemblages from the Atlas area are interpreted as a fourth biochore, compositionally intermediate between those of the Euro‐Boreal and Mediterranean. The Mediterranean biochore can be further divided into an intra‐ and a peri‐Mediterranean group. These five, palaeogeographically well‐constrained biochores show moderate to high degrees of species endemicity, ranging from 20% (Atlas) to 58% (Euro‐Boreal). Based on available evidence, and after a reasonable cutback of the customary scale of ranks, the following biogeographical categories and names are suggested for the western Tethyan Pliensbachian brachiopod biochores: Euro‐Boreal Province, Mediterranean Province (including an intra‐Mediterranean and a peri‐Mediterranean Subprovince), Pontic Province and Atlas Subprovince. In addition, a still poorly documented brachiopod biochore occurs on the Gondwana margin as a possible precursor of the extensive Middle to Late Jurassic Ethiopian Province. [ABSTRACT FROM AUTHOR]

Possible life cycle of some ancient plectambonitoids (order Strophomenida) from the Middle Ordovician of Russia is reconstructed based on the well‐preserved specimens composing the ontogenetic series. Four regions may be distinguished on their shell surface: protegulum, brephic shell, neanic shell and adult shell. The posterior margin of ventral protegulum bears pedicle sheath, which is a tubular outgrowth with a 40‐μm‐wide aperture at the distal end. The protegulum and brephic shell have common type of microstructure that possibly is spherular; the neanic and adult shells are fibrous. The strophomenide ontogeny possibly was similar to that of recent discinides. The strophomenide life cycle possibly included the planktotrophic juvenile stage; the protegulum and brephic shell were formed in the water column. The aperture of the pedicle sheath was possibly used as an anal opening of the floating juvenile and as an attachment organ during the settlement; at early adult stages, the sheath erased, the anus closed, and the animal started to lie on the ventral valve. The origin of the order Strophomenida and its relative groups is possibly connected with the loss of the pedicle lobe; judging by some strophomenide morphological features, true pedicle was present in the strophomenide ancestors. The tubes on the ventral umbones of strophomenides and billingsellides are not homologous as pedicle sheaths of strophomenides are formed at the planktotrophic swimming stage, and the tubes surrounding the pedicles of billingsellides were formed by deltidial plates of almost adult shell after settling. [ABSTRACT FROM AUTHOR]

Spiralia are lophophore‐supporting, coiled internal structures developed in some extinct brachiopods. In spite of considerable variations in their orientation, the spiralia of most spiriferide and spiriferinide taxa are known to be laterally directed. Recent studies have shown that these brachiopods consistently have a median inhalant and lateral exhalant feeding system. Here, we report a Permian spiriferellid brachiopod fossil (Spiriferella protodraschei) bearing ventrally directed spiralia in its interior. Using the serial sections of the specimen, we have reconstructed the detailed morphology and orientation of the spiralia. Each spiralium in the specimen does not show the apically tapering pattern supposedly universal in all the known types of spiralia: instead it maintains a similar diameter even at its last whorl. The spiralia appear to have directly developed from strong and anteriorly extended crura, consisting of ten whorls in one side and 13 whorls in the other side. As the morphology and orientation of spiralia are immediately associated with the arrangement of spirolophous lophophore within the mantle cavity, the extraordinary orientation and form of the spiralia indicate that this brachiopod likely had developed a considerably modified feeding pattern with respect to most other spirolophous brachiopods. It is postulated that the inhalant/exhalant current circulation of the species (and its descendants) would be considerably different from that of other spiriferide taxa. In particular, the combination of the vertically oriented life posture (free‐lying with thickened ventral apex bottom) and ventrally directed spiralia resembles both fossil atrypide and modern rhynchonellide brachiopods in the orientation of spirolophe, suggesting that some spiriferellid brachiopods may have developed a lateral inhalant/median exhalant feeding current system. A few spiriferide and spiriferinide brachiopod taxa with a weakly transverse but strongly convex ventral valve are noted to exhibit similar modifications in their spiralia, possibly due to the spatial limitation of their mantle cavities. [ABSTRACT FROM AUTHOR]

Exceptionally preserved, silicified and articulated complete shells of the rhynchonelliform kutorginate brachiopod Nisusia sulcata are redescribed from the middle Cambrian (Series 3) Marjum Limestone, Utah. Cylindroid sausage‐like protrusions, emerging posteriorly between the valves, were originally interpreted as faecal in origin, but restudy under the SEM shows that these features represent silicified pedicles as they are attached in situ to other Nisusia. The Nisusia host most likely was alive at the time of attachment. Restudy of the pedicles of Nisusia provides new phylogenetic information on the anatomy of the earliest rhynchonelliforms. The silicified pedicles differ considerably from the pedicles of living crown group rhynchonelliforms in being strongly annulated, distally tapering, and were likely to have been rather more flexible. The Nisusia pedicles are more similar to the exceptionally preserved pedicles from other Cambrian rhynchonelliform brachiopods, including Kutorgina, Longtancunella and Alisina, but these emerge from the ventral apical foramen rather than from between the valves as in Nisusia. Although generally similar, these two types of pedicles are unlikely to represent homologous structures as Nisusia is provided with both an apical foramen (possibly larval attachment) and a posterior adult pedicle. The similarities may be explained by similar type of accretionary growth from two different types of epithelia. The Nisusia‐like pedicle appeared early within the kutorginates and rhynchonellates. The discovery of hollow spines in Nisusia sulcata further supports the generic assignation of the species. [ABSTRACT FROM AUTHOR]

The Ordovician and Silurian of the Baoshan and Mangshi regions in western Yunnan Province, SW China, have long been regarded as being continuous and representative of the Sibumasu terrane. However, our recent biostratigraphical investigations of three Katian to Llandovery sections of predominantly clastic facies reveal a significant, largely correlative disconformity within the Upper Ordovician. These sections include the Laojianshan and Feida Storehouse sections in Baoshan, and the Shaodihe section in Mangshi. In the Baoshan region, the disconformity lies at the base of the overlying Jenhochiao Formation and spans a time interval from earliest late Katian (Dicellograptus complexus Biozone) to early Hirnantian (lower Metabolograptus extraordinarius Biozone), as constrained by the trilobites and brachiopods from the underlying strata and the graptolites from the overlying strata. In the Mangshi region, the disconformity lies at the base of the overlying Wanyaoshu Formation, spanning nearly the entire late Katian (Dicellograptus complexus Biozone to lower Paraorthograptus pacificus Biozone), as constrained by graptolites, trilobites and brachiopods from underlying and overlying beds. A considerably diverse, typical Hirnantia fauna occurs in the Wanyaoshu Formation, which is correlated with the same fauna from the Kuanyinchiao Formation in the Yangtze region, South China, and its equivalents elsewhere. A weathering crust of 10–20 cm in thickness occurs ubiquitously in both regions, in association with the disconformity. This stratigraphical gap within the Upper Ordovician in western Yunnan is probably resulted from the abrupt sea‐level drop induced by Late Ordovician Glaciations, or alternatively and less likely result from a regional tectonic uplift in northern Sibumasu terrane. [ABSTRACT FROM AUTHOR]

This study presents a Cambrian–Ordovician (Cambrian, ‘Series 3’ – Katian, Ka4) brachiopod α‐diversity curve for the Iberian terrane. Three diversity pulses characterized the northern Gondwanan margin through the studied interval; an initial increase in linguliformean diversity that culminated during the Tremadocian (Tr3); a second, Darriwilian (Dw2) pulse caused primarily by a rise in orthid species; and a third pulse during Katian times (Ka3–4) marking the most diverse and phylogenetically complex faunas recorded in this study. Each of the three diversity pulses is phylogenetically distinct and characterized by large turnover rates. The first pulse consists almost exclusively of remnants of the Cambrian Evolutionary Fauna, whereas the second pulse shows a sudden rise of clades typical of the Paleozoic Evolutionary Fauna. The fact that otherwise typical Cambrian clades also radiated at the dawn of the Ordovician suggests that whatever facilitated the emerging Ordovician Radiation, also benefitted these ancient lineages. However, eventually the succeeding Paleozoic Evolutionary Fauna came to dominate during the second diversity pulse. This pulse represents a high‐latitude correlative to the main pulse of the Ordovician Radiation. Although it coincides with a globally occurring transgression of eustatic nature, our analysis shows that the generic composition remained overwhelmingly endemic up through the Darriwilian–Sandbian interval. Opposed to this, the third pulse coincides with the globally occurring Boda warming event, which also marks a time of global dispersal. In Iberia, this is reflected by almost entirely cosmopolitan brachiopod faunas, suggesting that the phases of rapid speciation which characterize the Ordovician Radiation had ceased by the mid‐Katian. [ABSTRACT FROM AUTHOR]

During the Great Ordovician Biodiversification Event (GOBE), the number of marine invertebrate families more than tripled. Fundamental shifts in clade dominance and ecological structure led to the rise of the Palaeozoic Fauna and the second Palaeozoic Ecological Evolutionary Unit (EEU P2 of Sheehan), which revolutionized benthic ecosystems for the next 200 million years. Although general global signals of increased diversity and ecosystem restructuring are known, direct links between these changes are more poorly constrained on high‐resolution local scales. To address this, rhynchonelliformean brachiopod assemblages of the Middle Ordovician Simpson Group (Oklahoma, USA) were assessed before, during and after maximum local diversity increase related to the second global pulse of the GOBE. Stratigraphically constrained brachiopod species occurrence and abundance data were collected for Dapingian‐lower Sandbian strata via field study. Brachiopod assemblages exhibited declining dominance and increasing evenness from the Dapingian through middle Darriwilian stages followed by high volatility in index values during and after the GOBE interval. These patterns document local faunal turnover and shift from EEU P1 to P2. Furthermore, the average species body volume statistically increased over this interval, a pattern that is independent of phylogenetic constraints. Paired increase in mean body size and size disparity is evidence of niche specialization and utilization of additional food resources. Together, changes in body size, evenness and dominance indicate that increasing ecological complexity was coincident with diversification in Oklahoma. This suggests that a common mechanism, such as climate optimization or increased food abundance, was locally responsible for building both taxonomic diversity and ecological complexity during the GOBE. [ABSTRACT FROM AUTHOR]

The accumulation of diversity is dependent on the production (and subsequent continuation) of new species; thus, it is important to contextualize the Great Biodiversification Event (GOBE) as the sum of a series of individual speciation events. Studies of speciation processes are only beginning to emerge for the GOBE, but early analyses of brachiopods and other taxa suggest that such research questions are tractable given appropriate data sets and analyses. In order to understand the GOBE, it is important to move from correlating diversity trends with environmental changes to explicitly assessing how correlative Earth system processes can facilitate the process and mechanisms of speciation. Explicit consideration of the hierarchical structure and biogeographical aspects of evolutionary processes provides a dynamic perspective to analyse speciation. Biogeographical processes of dispersal and vicariance provide the link between local and global diversity levels, and oscillations between these two biogeographical modalities can generate an effective speciation dynamo. Geographical isolation due to palaeogeography, numerous interoceanic islands, tectonism, glacial–interglacial cycles and newly developed habitat heterogeneity were likely key factors in promoting speciation. Understanding the processes that produced the GOBE will require careful consideration of the oceanic, climatic and tectonic processes operating during the Early Palaeozoic as well as the speciation process itself. [ABSTRACT FROM AUTHOR]

Brachiopods are among the first animal phyla to emerge from the Cambrian Explosion, rapidly diversifying to all major palaeocontinental blocks within 20 million years. The group underwent another steep rise in diversity during the Ordovician, and their relative abundance and diversity made them one of the most successful invertebrate groups during the entire Palaeozoic. During this time, brachiopods lived in a range of environments and represented a significant component of marine ecosystems, yet information regarding their modes of life and ecology is somewhat limited. Recent studies, primarily from the Chengjiang and Burgess Shale Lagerstätten, have revealed that by the Middle Cambrian (Series 3, Stage 5) brachiopods from across the phylum had already developed a range of ecological strategies and life modes. Cambrian brachiopods occupied distinct trophic niches on soft and hard substrates and exhibited at least five types of lifestyles: pedicle attachment, pedicle anchoring, cemented, free‐lying and semi‐infaunal. Comparisons with Ordovician benthic assemblages show that despite the explosion of brachiopod taxa witnessed in the Ordovician, with the exception of the appearance of burrowing brachiopods, life strategies of brachiopods remained largely the same. Indicating that the majority of life modes observed in brachiopods had rapidly evolved and was already in place prior to the Great Ordovician Biodiversity Event. [ABSTRACT FROM AUTHOR]

The morphological variation of the sulcal development and shell outline in large Permian neospiriferine brachiopods including Fasciculatia Waterhouse, 2004 is investigated using geometric morphometrics. The sulcal tongues of spiriferide brachiopods can be, in a qualitative sense, categorized into three types according to the degree of their development: short sulcal tongue, long sulcal tongue and geniculated sulcal tongue. All three types have been noted within Fasciculatia striatoparadoxa, regardless of the nature of the substrate which they originally inhabited. To quantify its morphological variation both in sulcal development and shell outline, 51 brachiopod shells were scanned with a three-dimensional (3-D) surface imaging device, and their 3-D models were reconstructed. Using two landmarks and 58 semilandmarks designated on the surface of the reconstructed 3-D models, a landmark-based morphometric analysis was performed. Our result demonstrates a significant intraspecific variation of sulcal development in F. striatoparadoxa and its relatives. Local environmental factors, especially the intensity of ambient water flow, are invoked as the most likely cause for this intraspecific variation. Additionally, this study also shows that there are considerable interspecific distinctions in shell outline among Fasciculatia species, independent of the high variation in the sulcal development. The strong stability of overall shell outline at species level implies a decoupled morphological development between sulcal tongue and whole shell outline. The 3-D morphometric approach applied here demonstrates its great utility as a tool for quantifying and analysing the morphological variation of highly convex brachiopod shells. [ABSTRACT FROM AUTHOR]

Since the early 19th century, depressions in, and holes piercing through, the lower (ventral) valves of craniid brachiopods have been described as 'sunken muscle scars'. Examination of extant craniid material has shown that the characteristic surface texture of calcitic muscle scars, myotest, is not present in these so-called sunken muscle scars. Reconstruction of the musculature of a fossil specimen of Crania craniolaris with posteriorly directed, valve-piercing holes suggests that muscles could not have passed through these holes and been functional. It is proposed that recently discovered organic muscle attachment tissue that forms muscle attachment surfaces and organic rostella in some extant craniids was also present in fossil craniids and occupied so-called sunken muscles scars. Thus, in most cases, so-called sunken muscle scars are not muscle scars at all. New terminology is proposed for the organic muscle attachment tissues and so-called sunken muscle scars. The presence of calcitic and/or so-called sunken muscle scars introduces a significant level of morphological variation in some craniid genera and species. The taxonomy of craniid genera and species where the presence of so-called sunken muscle scars are part of the diagnosis or description should be reassessed. [ABSTRACT FROM AUTHOR]

To date, bivalve calcitic plates which cover the outer chitinous lamella of the lower jaws of Jurassic and Cretaceous ammonoids (aptychi sensu stricto) have been classified into several morphotypes (form genera) based on shape, surface sculpture and internal microstructure. However, previous works on aptychi microstructure focused mainly on thick morphotypes (e.g. Laevaptychus and Lamellaptychus), whereas little was investigated for thin Praestriaptychi. In this study, the microstructure of Praestriaptychi of Upper Oxfordian Perisphinctes and of recently discovered aptychi of aspidoceratid microconch Mirosphinctes (both belonging to the superfamily Perisphinctoidea) is described. These aptychi are compared with Laevaptychi of Upper Oxfordian macroconchs Euaspidoceras (a dimorphic counterpart of Mirosphinctes). This study demonstrated that the aptychi of Perisphinctes and Mirosphinctes differ from each other and from Laevaptychi in their microstructure, number of calcitic layers and in growth patterns. The aptychi of both aspidoceratid dimorphs are similar in terms of growth pattern, but differ in microstructure and the number of calcitic layers. Neither aptychi of Perisphinctes nor of Mirosphinctes have a tubular layer with a honeycomb surface pattern, which is typical for Laevaptychus. This indicates that aptychi were extremely diverse and their microstructure varied significantly not only within the superfamily, but even within a dimorphic pair of aspidoceratid ammonites. A lack of a tubular layer in Praestriaptychus indicates that it developed independently in Lamellaptychus of Haploceratoidea and Laevaptychus of Aspidoceratidae. [ABSTRACT FROM AUTHOR]

The rhynchonellid brachiopod Obliquorhynchia flustracea from the middle Danian (Paleocene) cool-water coral mounds of the Faxe Formation, Denmark, exhibits commissural asymmetry, a rare feature in articulate brachiopods. It has been much discussed whether the underlying reasons for this asymmetry were species specific caused by pedicle attachment in the limited space between the branches of the scleractinian Dendrophyllia candelabrum. The two species are always found together, and the brachiopod is essentially missing outside facies characterized by D. candelabrum. Based on morphological analyses and statistical tests, we suggest that ecophenotypic variation is the main reason for the variability in the external shell morphology and development of commissural asymmetry. Conditions such as sexual dimorphism and defects can be dismissed as a facilitating reason of phenotypic variation. This is a rare case where it is possible to directly link commissural asymmetry to mode of attachment on a specific host. [ABSTRACT FROM AUTHOR]

Well-preserved juvenile specimens of the orthotetide brachiopod Coolinia pecten (Linnaeus, ) from the Silurian of Gotland, Sweden, demonstrate evidence of a planktotrophic larval habit. Larval shell morphology indicates the absence of a pedicle sheath: this character is otherwise typical of derived billingsellides, strophomenides and productides, which form the conventional strophomenide clade. The presence of a rudimentary colleplax structure in the larval shell of Colinia suggests instead a phylogenetic link to chiliate brachiopods and the enigmatic genus Salanygolina. This relationship suggests an early divergence of rhynchonellate and strophomenate brachiopods. [ABSTRACT FROM AUTHOR]

Research on drilling predation, one of the most studied biological interactions in the fossil record, has been concentrated on prey with calcareous skeletons (e.g. molluscs, echinoids, rhynchonelliform brachiopods). Based on a compilation of literature sources and surveys of paleontological collections of the Florida Museum of Natural History and the National Museum of Natural History, we provide a tentative evaluation of the post-Palaeozoic history of drilling predation on the organophosphatic brachiopods of the family Lingulidae. Despite temporal, geographical and methodological limitations of the data assembled here, the results indicate that lingulide brachiopods have been subject to drilling predation since at least the Eocene. Variation in drilling frequencies at the locality level suggests that lingulides may occasionally experience somewhat elevated predation pressures from drilling organisms. Overall, however, drilling predation on lingulide brachiopods has been infrequent in the Cenozoic and may have been absent in the Mesozoic. The Mesozoic-to-Cenozoic increase in drilling frequencies on lingulides is similar to the trends observed in other marine benthic invertebrates and consistent with the hypothesis that predation pressures increased through time in marine ecosystems. [ABSTRACT FROM AUTHOR]

Fossil skeletal apatites vary in their composition and can yield mixed biochemical, environmental and diagenetic information. Thus, it is important to evaluate the diagenesis spatially inside the skeleton. We study the cross sections of shells of the Furongian lingulate brachiopod Ungula ingrica from Estonia using the Attenuated Total Reflectance -- Fourier Transform Infrared (ATR-FTIR) microspectroscopic and energy dispersive spectroscopic (EDS) mapping and show for the first time that different structural laminae of the shell have different chemical compositions. Compact laminae are rich in PO43-, Na, Mg and poor in F and Ca. Porous (baculate) laminae are rich in carbonate anions, Ca and F, but contain less Na and Mg. The ATR-FTIR spectra show further differences in the v2 carbonate region, where the IR band at 872 cm-1 in compact laminae is replaced by a strong band at 864 cm-1 in baculate laminae. The changes in shell apatite suggest different origins of the apatite phases. Compact laminae are likely chemically less altered and could potentially carry more reliable palaeoenvironmental or geochemical information than the apatite in baculate laminae, which is mostly authigenic in its origin. [ABSTRACT FROM AUTHOR]

Extant brachiopods and stalked crinoids are found together in the deeper waters of the Caribbean Sea. Analogous brachiopod/crinoid associations have been reported from diverse palaeoenvironments in the Neogene of the region. Studied examples include the Pleistocene of Jamaica (deeper water fore reef), and the Miocene of Jamaica (island slope chalks), Barbados (accretionary prism) and Carriacou (turbiditic siliciclastic shelf). Comparison with analogous modern environments indicates deposition in 150+m water depth. This association has now been extended back into the Late Oligocene. Crinoids and brachiopods both occur in the Antigua Formation of Antigua; both occur high in the formation, implying deeper water in this retrograde succession. They have received little attention from systematists, although the brachiopods Cistellarcula dubia Cooper and Tichosina foresti Cooper have previously been described from the Antigua Formation; to these, we add Cistellarcula sp., Argyrotheca sp. and Tichosina sp. At Half Moon Bay in southeast Antigua, high in the Antigua Formation, we have found columnals of isocrinid crinoids (cf. Isocrinus sp.) associated with rare brachiopods ( Terebratulina sp.) in island slope deposits. These taxa provide independent evidence for the deeper water aspect of this part of the Antigua Formation, in beds that also yield large, thin-walled fossil sponges. [ABSTRACT FROM AUTHOR]

The history of the Iapetus Ocean in the Early Palaeozoic is well-established, and faunal distribution has contributed significantly to the development of this knowledge; however, lingulate brachiopods have traditionally been considered to be of little utility in assessing palaeobiogeography. The distribution of lingulate brachiopods across the Iapetus region is analysed using a number of similarity indices and other statistical measures. This analysis shows a clear palaeobiogeographic signal where lingulate faunas are sufficiently diverse, reflecting the history of the Iapetus ocean and the relative separation of Laurentia and Baltica through the Cambrian and Ordovician. Lingulate faunas on Avalonia are, however, low in diversity and show relatively high endemism; this renders them of little use in assessing the separation of Avalonia from other areas. Evidence of earlier increases in faunal similarity in lingulate faunas between continents, compared to other fossil groups, provides confirmatory evidence that Palaeozoic lingulates had long-lived planktotrophic larvae. [ABSTRACT FROM AUTHOR]

The oldest Foliomena fauna was, until now, known from the middle-upper Miaopo Formation ( Nemagraptus gracilis Biozone, lower Sandbian, basal Upper Ordovician) of South China. In this study, the oldest record of the fauna is set back to the latest Darriwilian (upper Hustedograptus teretiusculus Biozone), represented by Foliomena jielingensis and some typical constituents of the Foliomena fauna from the basal Miaopo Formation at Jieling, northern Yichang, western Hubei Province, central China. The Miaopo Formation is characterized by its organic-rich dark-grey shale facies, unique in its localized distribution on the Yangtze Platform, and distinguished by its rich and diverse benthic and graptolitic faunas. This suggests an origin of the Foliomena fauna in periodically oxygen-starved local depressions on the Yangtze Platform during the Middle-Late Ordovician transition. [ABSTRACT FROM AUTHOR]

Silurian brachiopods of Middle Llandovery ( Aeronian) ages are reviewed, and 215 genera are identified here, compared with 109 in the preceding Early Llandovery ( Rhuddanian), indicating a recovery-radiation interval after the end- Ordovician mass extinction. The chief regions in which they are found are the continents of South China, Avalonia- Baltica, Laurentia and Siberia, which were all at tropical latitudes with the exception of Avalonia. In addition, the very large superterrane of Gondwana, although with patchy brachiopod distribution, included temperate faunas, as well as subtropical faunas (in Iran and Afghanistan). Aeronian brachiopods greatly increased in diversity, with dominance of four major groups: orthides and strophomenides (which had flourished previously in the Rhuddanian), pentamerides and atrypides (which became dominant in the Aeronian), and many newly evolved taxa, and occupied deeper water and wider ecological niches (level bottom and reef) than those in the Rhuddanian. Each of the continents has some endemic genera, but there is a greater proportion of them in South China, where some groups (such as the pentamerides and atrypides) are more diverse and others, such as the orthides, are much less common than elsewhere. Affinity indices ( AI) show that two megaunits can be recognized: South China and Avalonia-Baltica-Laurentia ( ABL); Siberia seems to have been loosely connected with ABL and even more loosely to South China presumably because of its geographical separation in the Northern Hemisphere. The separation of South China from the other megaunits is further supported by cluster analysis. [ABSTRACT FROM AUTHOR]

Two morphologies of drillhole, probably attributable to gastropods, have been recognized in specimens of the small extant New Zealand platidiid brachiopod Neoaemula vector, collected from Fiordland, New Zealand. Some of these drillholes have been repaired, and these repairs occur in two different ways. The thin replacement shell has both primary and secondary layers and in some cases is punctate. Drillhole repair is virtually unknown among living brachiopods, but this may due to successfully repaired drillholes being classified as abandoned or incomplete. [ABSTRACT FROM AUTHOR]

Predatory gastropod drill holes are an abundant and easily identifiable signal of predation in ancient and modern molluscan shell assemblages. Many workers have used drill holes to interpret patterns of predation intensity and success in fossil assemblages. These studies are predicated on the assumption that the relative abundances of drilled and undrilled shells in an assemblage accurately reflect those of the community from which the shells were originally derived. The underlying assumption is that drilled and undrilled shells are transported into shell accumulations in the same manner. If this assumption is false, shell accumulations do not represent taphonomically unbiased samples, but rather preferentially sorted deposits from which conclusions about drilling predation cannot be made. To test the hypothesis that drilled and undrilled gastropod shells transport at different flow velocities, multiple transport trials were conducted on two morphologically distinct taxa, Olivella biplicata and Euspira lewisii. Individual specimens were placed in a recirculating flume tank and observed from rest (in stable orientation) until they were transported downstream. During each trial, flow velocity was slowly and incrementally increased, so as to avoid pulses of acceleration, until shells began to move downstream. Drilled and undrilled specimens of both taxa demonstrate statistically significant correlations between shell mass and average transport velocity. Similarly sized drilled and undrilled specimens of both taxa do not exhibit significant differences in transport velocity. These results indicate that predatory drill holes do not change the hydrodynamic properties of gastropod shells. Therefore, gastropod shell assemblages are not likely to be affected by differential transport and sorting of drilled and undrilled shells. [ABSTRACT FROM AUTHOR]

The distinctive brachiopod Dicoelosia King 1850 is characterized by a strongly bilobed outline. To date, studies have concentrated on its functional morphology, taxonomy and evolution; little attention has been paid to its ontogeny. Here, we map population variation by principal component analysis for over 80 specimens distributed across five species of Dicoelosia. Using geometric morphometrics with landmarks for some 40 specimens, the ontogenic trends in D. sp. nov. are compared with those of Dicoelosia biloba. In addition, the ontogenic pathway in D. sp. nov. is investigated by morphing with control points, a new technique introduced here to palaeontology. Combining the results above, the ontogeny of the key character of the genus, emargination, is modelled. Within single populations, taxa may develop from broad weakly emarginate forms into those that are elongate and deeply emarginate. As the identification of the genus and its species depends on external morphological characters, the definition of ontogenetic trends in each species is essential for taxonomic discrimination. Substantial population variation exists in many of its species; however, the morphing technique provides a method of simulation, predicting the full range of ontogenetic variation in given populations. [ABSTRACT FROM AUTHOR]

Benedetto, J.L. 2013: Presence of punctae in the 'plectorthoidean' brachiopod Famatinorthis turneri (Middle Ordovician) from western Argentina: implications for early diversification of punctate orthides. Lethaia, Vol. 46, pp. 170-179. Famatinorthis Levy & Nullo is a distinctive orthide brachiopod of Dapingian age from the volcaniclastic rocks of the Famatina Range of western Argentina. Although it was originally classified among the plectorthoideans, a new collection from the La Escondida Formation has yielded exceptionally well-preserved moulds of Famatinorthis turneri in which silicified infillings of punctae are clearly visible, leading to the reassignment of the genus to the dalmanellidines. In this paper, phylogenetic analyses are used to determine the evolutionary relationships of Famatinorthis, the Tremadocian linoporellid Lipanorthis, and other Ordovician Gondwanan genera. The placement of Plectorthoidea in the same major clade as linoporellids, and the separation of Dalmanellidina as an independent clade are the most important features of all shortest trees, supporting the idea that linoporellids may have originated from a plectorthoid ancestor. Cladistic analysis reveals that Lipanorthis lies close to the ancestry of the linoporellid lineage, and Famatinorthis clusters within the more derived taxa of the clade with which it shares a large septalium. It seems that the presence of endopunctae in the orthides does not necessarily indicate close phylogenetic relationships as it could have occurred at different times in different clades. If the homoplasic nature of endopunctae in the order Orthida is supported by further morphologic and phylogenetic studies, the fundamental division of orthides in non-punctate (Orthidina) and punctate (Dalmanellidina) may need revision. □ Brachiopods, Ordovician, Gondwana, Famatina, phylogeny, punctate orthides. [ABSTRACT FROM AUTHOR]

Multivariate analysis based on nine biometric characters of 171 Late Ordovician rhynchonellide specimens from nine upper Sandbian-upper Katian localities in North America supports the hypothesis that one of the diagnostic taxa of the North American epicontinental brachiopod fauna, Hiscobeccus, evolved from Rhynchotrema, which lived predominantly in peri-cratonic settings. The oldest known Hiscobeccus, H. mackenziensis of early Katian age, exhibits transitional characteristics between Rhynchotrema and Hiscobeccus, and it clusters more closely with Rhynchotrema than with younger species of Hiscobeccus of mid-late Katian (Maysvillian-Richmondian) age. Diversification of the Hiscobeccus lineage in epicontinental seas was characterized by drastic increase in shell size, globosity and lamellosity, especially in palaeoequatorially located inland basins. Such morphological trends are interpreted as adaptation to relatively shallow, muddy substrates, moderate water turbulence, relatively low oxygen content and unstable supply of nutrients in generally overheated epicontinental seas with sluggish circulation. [ABSTRACT FROM AUTHOR]

Pruss, S.B., Clemente, H. & Laflamme, M. 2012: Early (Series 2) Cambrian archaeocyathan reefs of southern Labrador as a locus for skeletal carbonate production. Lethaia, Vol. 45, pp. 401-410. Archaeocyathan reefs, the first reefs produced by animals, are prominent, global features of early Cambrian successions. However, microbialites - the dominant reef components of the Proterozoic - were still abundant in most archaeocyathan reefs. Although such reefs were a locus for carbonate production, it is unclear how much carbonate was produced skeletally. This analysis of well-known early Cambrian archaeocyathan patch reefs of the Forteau Formation, southern Labrador, demonstrates that skeletal carbonate was abundantly produced in these archaeocyathan reefs, although only about half was produced by archaeocyathans. Trilobites, echinoderms and brachiopods contributed substantially to the total carbonate budget, particularly in grainstone facies flanking the reefs. Through point count analysis of samples collected from the reef core and flanking grainstones, it can be demonstrated that skeletal material was most abundant in grainstone facies, where animals such as trilobites and echinoderms contributed significantly to carbonate production. In contrast, microbial fabrics were more abundant than skeletal fabrics in the reef core, although archaeocyathan material was more abundant than other skeletal debris. Similar to modern reefs, these reefs created a variety of habitats that allowed for the proliferation of skeletal organisms living on and around the reef, thereby promoting skeletal carbonate production through ecosystem engineering. □ Archaeocyatha, bioherms, carbonates, calcification, point count analysis [ABSTRACT FROM AUTHOR]

Colás, J. & García Joral, F. 2011: Morphology and environment in the Jurassic Nucleatidae (Brachiopoda) from Western Tethys. Lethaia, Vol. 45, pp. 178-190. Nucleatidae (Brachiopoda, Terebratulida) are commonly considered as typical members of the Mediterranean assemblages during the Jurassic. However, nucleatids occasionally also occur in the margins of Western Tethys (Northwestern European shelf). Some of these occurrences in northeastern Spain are analysed, detecting a relation between nucleatid morphology and palaeoenvironment during the Jurassic. The validity of this relationship for the whole of the representatives of the group in the Western Tethys during the Jurassic is tested by means of morphofunctional analyses (principal components analysis and discriminant analysis), concluding that reduction of the lateral expansion of the shell is the key morphological feature whereby epioceanic and epicontinental taxa differ. This change can have functional significance because it can be interpreted as a mechanism to reduce the area exposed when the valves gape, increasing protection against harmful particles in environments characterized by higher terrigenous input. Some modifications on the systematics of the Nucleatidae at the genus level are proposed on the basis of the temporal and biogeographical distribution of these adaptations. □ Brachiopods, Nucleatidae, functional morphology, adaptation, systematics, Jurassic, Spain. [ABSTRACT FROM AUTHOR]

Zhang, Z., Holmer, L. E., Ou, Q., Han, J. & Shu, D. 2011: The exceptionally preserved Early Cambrian stem rhynchonelliform brachiopod Longtancunella and its implications. Lethaia, Vol. 44, pp. 490-495. The extraordinary Longtancunella chengjiangensis is one of the rarest and most problematic brachiopods from the Early Cambrian Chengjiang Lagerstätte, where it occurs in unique gregarious clusters with up to ten individuals attached by their stout pedicles to a single hard exoskeleton. Although the general morphology and soft anatomy of Longtancunella is available, its taxonomy and systematic placement within the Brachiopoda remains problematic. New exceptionally preserved specimens show that the pedicle of Longtancunella cannot be considered homologous with the pedicles in crown Rhynchonelliformea or Linguliformea. The pedicle of Longtancunella emerges from a ventral umbonal foramen with a rounded plate that must have been secreted by specialized ventral mantle epithelium. The rounded plate is proposed to be a homologue to the colleplax - a plate covering the umbonal foramen, which is otherwise known from the extinct rhynchonelliform chileates. Longtancunella is proposed to represent a soft-shelled stem rhynchonelliform brachiopod with chileate features, thus demonstrating for the first time that the chileate-like umbonal perforation functions as a pedicle opening. The unusual preservation of the annulated chileate-like holdfast supports the view that it may have been secreted as stacks of chitinous or even mineralized 'attachment pads'. Together with having a spirolophous lophophore and U-shaped gut, Longtancunella displays a unique mixture of linguliform and rhynchonelliform characters that throw new light on an early stage of rhynchonelliform diversification. □ Brachiopods, Cambrian, Chengjiang Lagerstätte, Chileata, colleplax, pedicle. [ABSTRACT FROM AUTHOR]

Popov, L.E., Bassett, M.G., Holmer, L.E., Skovsted, C.B. & Zuykov, M.A. 2010: Earliest ontogeny of Early Palaeozoic Craniiformea: implications for brachiopod phylogeny. Lethaia, Vol. 43, pp. 323–333. Well preserved specimens of the Early Palaeozoic craniiform brachiopods Orthisocrania and Craniops retain clear evidence of a lecithotrophic larval stage, indicating the loss of planktotrophy early in their phylogeny. The size of the earliest mineralized dorsal shell was <100 μm across, and the well preserved shell structure in these fossil craniiforms allows their earliest ontogeny to be compared directly with that of living Novocrania, in which the first mineralized dorsal shell (metamorphic shell) is secreted only after settlement of the lecithotrophic larvae. Immediately outside this earliest shell (early post-metamorphic or brephic shell) and in the rest of the dorsal valve the primary layer in both fossil and living craniiforms has characteristic radially arranged laths, which are invariably lacking in the earliest dorsal shell. The ventral valve of the fossil specimens commonly preserves traces of an early attachment scar (cicatrix), which is equal in size to the dorsal metamorphic shell, and the brephic post-metamorphic ventral valve also has a primary shell with radially arranged laths. However, a primary shell with radial laths is completely lacking in the ventral valve of living Novocrania, indicating that heterochrony may have been involved in the origin of the encrusting mode of life in living craniids; the entire ventral valve of Recent craniids (with the possible exception of Neoancistrocrania) may correspond to the earliest attachment scar of some fossil taxa such as Orthisocrania. It is also probable that the unique absence of an inner mantle lobe as well as the absence of lobate cells in Novocrania could be the result of heterochronic changes. The dorsal valve of both fossil and living craniiforms has a marked outer growth ring, around 500 μm across, marking the transition to the adult, and a significant change in regime of shell secretion. The earliest craniiform attachment is considered to be homologous to the unique attachment structures described recently in polytoechioids (e.g. Antigonambonites) and other members of the strophomenate clade. However, unlike the craniiforms, polytoechioids and strophomenates all have planktotrophic larvae, and planktotrophy is most probably a plesiomorphic character for all Brachiopoda. □ Brachiopoda, Craniiformea, Early Palaeozoic, ontogeny, phylogeny. [ABSTRACT FROM AUTHOR]

Shiino, Y. 2009: Passive feeding in spiriferide brachiopods: an experimental approach using models of Devonian Paraspirifer and Cyrtospirifer. Lethaia, Vol. 43, pp. 223–231. Passive feeding flows of two Devonian spiriferide brachiopods, Paraspirifer bownockeri and Cyrtospirifer sp., were examined experimentally using transparent hollow models and a flowing water tank. The models were constructed with polycarbonate plates using a vacuum heat press method. Another model of Paraspirifer with a spiral brachidium was constructed for the visualization of passive flow. The results of the ventral and dorsal directions of the hollow models suggest that outflow was generated through lateral gapes in the shell, while intake may have occurred through a sulcus gape. The passive internal flow inside the models invariably exhibited gyrating behaviour, and the axis of the rotation was similar to that of the spiral lophophore in spiriferides. Comparing the results using the hollow and backbone models indicates that the internal structures, which consisted mostly of the spiral brachidium, aided in adjusting the gyrating flows around the brachidium, even when the lateral region of the shell faced upstream. Extant terebratulides are known to generate gyrating flows around the median coils of the major feeding area, and this model best fits the relationship between the passive internal flows and the form of the lophophore. As a consequence, the shell forms of spiriferides could generate passive feeding flows from the gyrating movement surrounding the lophophore that are effective for feeding by the spiral lophophore. □ Brachiopoda, flume experiment, functional morphology, impingement feeder, physiology, suspension feeder. [ABSTRACT FROM AUTHOR]

Schemm-Gregory, M. & Sutton, M. 2010: First report of brachiopod–brachiopod endoparasitism. Lethaia, Vol. 43, pp. 111–115. The first example of brachiopod–brachiopod endoparasitism is reported from the Lower Devonian of China. Three-dimensional reconstructions following serial sectioning show a specimen of a strophomenide ( Dicoelostrophia sp.) within an articulated shell of the spiriferide Rostrospirifer tonkinensis; morphological modifications of the host and the positioning of the strophomenide with respect to the inhalant current demonstrate the in vivo nature of the association. The symbiosis is interpreted as parasitic; it appears to be facultative but demonstrates the viability of this mode of life, expanding the ecological range known to be exploitable by the Brachiopoda. □ 3-D reconstruction, Brachiopoda, Dicoelostrophia, endoparasitism, Lower Devonian, Rostrospirifer. [ABSTRACT FROM AUTHOR]

A characteristic etching trace, comparable to those produced by pedicles of some Recent brachiopods, was found on a Late Cretaceous, Campanian oyster shell from a mangrove-like setting in the Åsen quarry, Sweden. The trace fossil belongs to the ichnospecies Podichnus centrifugalis Bromley & Surlyk, 1973 and is, together with a single specimen of Crania craniolaris Linnæus, 1758, the only evidence of brachiopods in the mangrove-like environment. [ABSTRACT FROM AUTHOR]

Studies of ecosystem level changes in the geological record have found that the major extinction events eliminated many incumbent clades that had been ecologically dominant for long intervals. Surviving clades that had not been able to compete with the extinct incumbents were then able to evolve adaptations that allowed them to move into the niches vacated by the incumbents. Underlying this pattern is the inability of clades that do not occupy a particular niche to evolve adaptations that would permit them to compete with incumbent clades that are already successfully occupying that niche. The zoogeographic distributions of brachiopods in the Late Ordovician of Laurentia may also have been maintained by incumbency, which was disrupted by the end-Ordovician extinction event. Following the extinction event, an Early Silurian zoogeographic reorganization occurred, during which surviving clades evolved into the vacated epeiric sea niches in the Early Silurian. Just as incumbency plays a role in long-term evolutionary patterns, zoogeographic realms and provinces are also partially maintained by incumbency. [ABSTRACT FROM AUTHOR]

Bulk samples of brachiopods from the middle and upper parts of the Arnestad Formation and the entire Frognerkilen Formation in the Oslo Region demonstrate major vertical changes in the Sandbian to Katian amphicratonic fauna of this part of the Baltic Province. The main influx of new taxa occurred in the upper part of the Arnestad Formation (uppermost Sandbian), and in the succeeding Frognerkilen Formation (basal Katian). Faunal change is initially reflected in an increase in diversity and not as a replacement of the previously incumbent genera, which remain throughout the studied sequence. The majority of the new genera migrated from the East Baltic Region or through this region from Avalonia, while the marginal Laurentian taxa first occupied the Scandinavian part of Baltica. Six taxa migrated from Laurentia, three from Avalonia, two from Gondwana and one apparently originated on the South China palaeoplate. The faunal shifts and immigration of brachiopods appear to have been in response to an initial transgression together with the movement of Baltica into more warm temperate latitudes, but the diverse faunas developed both against a background of subsequent regression and in response to an offshore shift of biofacies. The new amphicratonic fauna was thus generated by faunal shifts from elsewhere in the Baltic Province to the marginal environments of the Oslo Region together with more exotic elements from neighbouring continents and microcontinents. [ABSTRACT FROM AUTHOR]

This study determines the distribution of magnesium and sulphur in the shells of two species of brachiopod from the same environment to highlight environmental and biological influences on shell composition. In Terebratulina retusa there are differences in magnesium concentration between the primary layer and the outer and inner regions of the secondary layer. In contrast, Novocrania anomala has a shell composed of high magnesium calcite and there is no significant difference in magnesium concentration between the primary and the secondary shell layers. Sulphur provides an indication of the distribution of sulphated organic matrix within the shells of T. retusa and N. anomala. In T. retusa the distribution of magnesium and sulphur correlates across the shell; however, there is no evidence for a relationship between magnesium and sulphur distribution in N. anomala. The relationship between magnesium and sulphur in T. retusa indicates that a proportion of the magnesium content of the shell is associated with the sulphated fraction of the organic matrix. In these two species of brachiopod, from the same environment, magnesium and organic concentration and distribution are very different, emphasizing the importance of fully understanding the factors that control biomineral composition before the application of these biominerals to environmental studies. [ABSTRACT FROM AUTHOR]

One hundred and twenty-five linguliformean brachiopods of late Marjuman (Cambrian) age with shell perforations, presumably caused by predation, were recovered from shallow-water limestones at two localities of the Deadwood Formation in the Black Hills of South Dakota, USA. Three-quarters of the perforated valves belonged to taxa in the order Acrotretida, while one-quarter of the specimens belonged to those of the order Lingulida. This is the first report of predation of fossil lingulids. In both orders there was a marked selection for valve type. Ninety-five per cent of all perforations of acrotretids were in the ventral valve, while 87% of all perforations of lingulids were in the dorsal valve. The highest rate of predation of collected acrotretids, at any stratigraphic horizon, was 22%, while the rate of predation of collected lingulids, at any given stratigraphic horizon, was as high as 9%. Half of the perforated valves had round holes with a sharp, non-beveled exterior edge, and half had irregularly shaped holes with chipped interior edges. The former type is attributed to either boring or a swift, piercing percussive strike, while the latter is attributed to a smashing percussive strike with a blunt appendage. A third type of perforation consisting of minute, roughly circular holes is thought to be too small to be the work of predators, and is assumed to be the result of an encrusting organism or parasite. The different types of perforation seen in the brachiopod valves indicate that there was more than one type of predator attacking them, including possibly one of the earliest durophages. Various hypothetical predators are suggested as potential candidates for causing the shell perforations. The criteria for their selection as possible linguliformean predators include possessing the ability to produce one of the two types of shell perforation, and being small enough to warrant preying on small (< 2 mm) brachiopods. [ABSTRACT FROM AUTHOR]

Longtancunella chengjiangensis, one of the sparse lingulid brachiopods from the Early Cambrian Chengjiang Lagerstätten of southwestern China, is characterized by a sub-circular shell shape, stout pedicle, and notably by gregarious occurrences in the fossils. This brachiopod form was briefly reported in 1999, but its detailed description, however, remains to be done. The material in our collection is remarkably well preserved and allows accounts of the shell morphology and of valve interiors, including lophophores, mantle canals, and a digestive tract. When compared with the coeval lingulid brachiopod Xianshanella haikouensis Zhang & Han, 2004, L. chengjiangensis exhibits some distinct features, notably tenuous marginal setae and distinguishable mantle canals and a relative short pedicle tapering posteriorly. [ABSTRACT FROM AUTHOR]

New data on the earliest ontogeny of Mid-Ordovician Baltoscandian clitambonitoid ( Apomatella, Neumania and Oslogonites) and polytoechioid ( Antigonambonites and Raunites) brachiopods reveal significant differences in the life history of the taxa belonging to these two superfamilies. The Polytoechioidea and probably other members of the Billingsellida had planktotrophic larvae, in which the dorsal and ventral mantle lobes formed separately and without reversion. The ‘pedicle sheath’ in Antigonambonites is secreted by a section of modified ventral mantle and thus this ‘pedicle’ is not homologous within the pedicle of rhynchonellate brachiopods. It is likely that polytoechioids and other members of the strophomenate clade had the same type of ontogeny and mode of attachment. In contrast, the ontogeny and mode of attachment of clitambonitoids are similar to that of recent rhynchonellates: their mantle lobes and both valves formed simultaneously, and the pedicle most likely formed from the larval pedicle lobe. Evidence for the lecithotrophic nature of clitambonitoid larva is discussed. This confirms that the Clitambonitoidea, unlike the Polytoechioidea, represents an ingroup within the Rhynchonellata. [ABSTRACT FROM AUTHOR]

The linguloid brachiopod shell family has been the focus of several studies because of the similarity in the composition of the mineral phase of these shells to that of human bone. However, ultrastructural features of Lingula shells have not yet been fully demonstrated at high magnification using Transmission Electron Microscopy (TEM) and Electron Diffraction. Ultrastructural characterization of the mineral phase in Lingula shells will improve our understanding of the biomineralization processes and mineral/organic interaction in more complex systems such as in bone or in other human mineralized tissues. In this study, the mineral phase of Lingula adamsi was characterized using a combination of ultrastructural and crystallographic techniques. The results showed that L. adamsi shells consist of apatite crystals of varying size, shape, and orientation in different areas of the shell. The c-axis of apatite was parallel to the shell surface and crystals were organized in different laminae. Compared to trabecular bovine bone, L. adamsi shells demonstrated a higher crystallinity and a lower amount of carbonate and organic compounds. This study therefore demonstrated how dissimilar organic matrix between L. adamsi shell and trabecular bone can modify the ultrastructural characteristics of apatite crystals in these two biomineralized tissues. [ABSTRACT FROM AUTHOR]

The Ordovician radiation was one of the most marked and sustained increases in Phanerozoic biodiversification; nevertheless it occurred against a background of minimal global climatic and environmental perturbations. Detailed investigations of the Ordovician successions on the Yangtze Platform of the South China palaeoplate indicate that: (1) the brachiopod α- and β-diversity changes are diachronous; (2) macroevolutionary patterns were different across the South China palaeoplate, with the Early Ordovician brachiopod radiation first occurring in normal marine, shallow-water environments and then moving gradually to both nearer-shore and offshore locations; (3) the main contributors to the initial Ordovician brachiopod radiation were the Orthida and Pentamerida; the typical Ordovician brachiopod fauna, dominated by the Orthida and Strophomenida, did not appear until the late Mid Ordovician ( Undulograptus austrodentatus Biozone) when the Strophomenida apparently replaced the dominant position of the Pentamerida within the fauna; (4) different ecotypes (e.g., sessile benthos, mobile benthos together with pelagic and planktonic organisms) demonstrate substantially different macroevolutionary patterns. The Ordovician brachiopod radiation of South China was apparently earlier than that suggested by global trends together with the data available from other palaeoplates or terranes, which may be related to its unique palaeogeographic position (peri-Gondwanan terrane gradually moving to equatorial latitudes). [ABSTRACT FROM AUTHOR]