Jeffrey R Thompson

University of Southampton · Institute for Life Sciences (IfLS)

Establishing a timeline for the evolution of novelties is a common, unifying goal at the intersection of evolutionary and developmental biology. Analyses of gene regulatory networks (GRNs) provide the ability to understand the underlying genetic and developmental mechanisms responsible for the origin of morphological structures both in the developm...

Echinoids, or sea urchins, are rare in the Palaeozoic fossil record, and thus the details regarding the early diversification of crown group echinoids are unclear. Here we report on the earliest probable crown group echinoid from the fossil record, recovered from Permian (Roadian-Capitanian) rocks of west Texas, which has important implications for...

Mechanistic understanding of evolutionary divergence in animal body plans devolves from analysis of those developmental processes that, in forms descendant from a common ancestor, are responsible for their morphological differences. The last common ancestor of the two extant subclasses of sea urchins, i.e., euechinoids and cidaroids, existed well b...

The Permian–Triassic bottleneck has long been thought to have drastically altered the course of echinoid evolution, with the extinction of the entire echinoid stem group having taken place during the end-Permian mass extinction. The Early Triassic fossil record of echinoids is, however, sparse, and new fossils are paving the way for a revised inter...

The Permian is regarded as one of the most crucial intervals during echinoid evolution because crown group echinoids are first widely known from the Permian. New faunas provide important information regarding the diversity of echinoids during this significant interval as well as the morphological characterization of the earliest crown group and lat...

Seawater magnesium (Mg) and calcium (Ca) have undergone secular fluctuations throughout the Phanerozoic, controlling whether the dominant calcium carbonate precipitant is calcite or aragonite + high-Mg calcite. Although these oscillations in seawater Mg/Ca ratios have been implicated as an important control on Phanerozoic diversification of calcify...

The extraxial-axial theory (EAT) and universal elemental homology (UEH) are often portrayed as mutually exclusive hypotheses of homology within pentaradiate Echinodermata. EAT describes homology upon the echinoderm bauplan, interpreted through early post-metamorphic growth and growth zones, dividing it into axial regions generally associated with e...

The Ordovician and Silurian are an exceptionally important interval of time for understanding the effects of ancient climate change on the paleobiodiversity of echinoderms. Despite this importance, the fossil record of many echinoderm groups during this interval is sparse. The echinoids, or sea urchins, are no exception; and new fossil finds are ne...

The echinoderms are an ideal group to understand evolution from a holistic, interdisciplinary framework. The genetic regulatory networks underpinning development in echinoderms are some of the best known for any model group. Additionally, the echinoderms have an excellent fossil record, elucidating in in detail the evolutionary changes underpinning...

The echinoids of the order Bothriocidaroida represent the initial burst of sea urchin diversification. They were the first echinoids to achieve widespread biogeographical dispersal and achieved high levels of species richness compared to other clades of stem group echinoids. Following long-standing controversy regarding their phylogenetic affinitie...

Echinoids are key components of modern marine ecosystems. Despite a remarkable fossil record, the emergence of their crown group is documented by few specimens of unclear affinities, rendering their early history uncertain. The origin of sand dollars, one of its most distinctive clades, is also unclear due to an unstable phylogenetic context. We em...

Echinoderms are characterized by a distinctive high-magnesium calcite endoskeleton as adults, but elements of this have been drastically reduced in some groups. Herein, we describe a new pentaradial echinoderm, Yorkicystis haefneri n. gen. n. sp., which provides, to our knowledge, the oldest evidence of secondary non-mineralization of the echinoder...

The fossil record is notoriously imperfect and biased in representation, hindering our ability to place fossil specimens into an evolutionary context. For groups with fossil records mostly consisting of disarticulated parts (e.g., vertebrates, echinoderms, plants), the limited morphological information preserved sparks concerns about whether fossil...

Understanding the varied environmental, biological, and geological processes which control preservation in the fossil record is crucial for assessing their impact on our perception of ancient biodiversity. Despite this, there are few large datasets which have been used to quantify the preservational state of whole clades or animal groups, and the f...

Echinoids are key components of modern marine ecosystems. Despite a remarkable fossil record, the emergence of their crown group is documented by few specimens of unclear affinities, rendering their early history uncertain. The origin of sand dollars, one of its most distinctive clades, is also unclear due to an unstable phylogenetic context. We em...

Free-swimming planktonic larvae are a key stage in the development of many marine phyla, and studies of these organisms have contributed to our understanding of major genetic and evolutionary processes. Although transitory, these larvae often attain a remarkable degree of tissue complexity, with well-defined musculature and nervous systems. Amongst...

The Cincinnatian (Katian) of the Cincinnati Tri-State area is widely regarded as one of the most fossiliferous sections known (Meyer and Davis, 2009). Echinoderms from these strata include well-described asteroids, crinoids, cyclocystoids, edrioasteroids, glyptocystoids, mitrates, and ophiuroids. John Pope discovered a partially articulated echinod...

Background Understanding the molecular and cellular processes that underpin animal development are crucial for understanding the diversity of body plans found on the planet today. Because of their abundance in the fossil record, and tractability as a model system in the lab, skeletons provide an ideal experimental model to understand the origins of...

Free-swimming planktonic larvae are a key stage in the development of many marine phyla, and studies of these organisms have contributed to our understanding of major genetic and evolutionary processes. Although transitory, these larvae often attain a remarkable degree of tissue complexity, with well-defined musculature and nervous systems. Amongst...

Understanding the molecular and cellular processes that underpin animal development are crucial for understanding the diversity of body plans found on the planet today. Because of their abundance in the fossil record, and tractability as a model system in the lab, skeletons provide an ideal experimental model to understand the origins of animal div...

Although squamates have an extensive fossil record spanning over 242 million years, a substantial number of fossil squamate generic and specific diagnoses are based on isolated and often incompletely-preserved skeletal specimens. This apparent bias represents a major hurdle in understanding squamate evolution through geologic time, and is a consist...

Phylogenomic and paleontological data constitute complementary resources for unravelling the phylogenetic relationships and divergence times of lineages, yet few studies have attempted to fully integrate them. Several unique properties of echinoids (sea urchins) make them especially useful for such synthetizing approaches, including a remarkable fo...

Quantifying morphological evolution is key to determining the patterns and processes underlying the origin of phyla. We constructed a hierarchical morphological character matrix to characterize the radiation and establishment of echinoderm body plans during the early Paleozoic. This showed that subphylum-level clades diverged gradually through the...

Several unique properties of echinoids (sea urchins) make them useful for exploring macroevolutionary dynamics, including their remarkable fossil record that can be incorporated into explicit phylogenetic hypotheses. However, this potential cannot be exploited without a robust resolution of the echinoid tree of life. We revisit the phylogeny of cro...

The mass occurrence of turritelline gastropod shells from the Lower Miocene of southern Germany allows for detailed studies of their palaeoecology, transport mechanisms, preservation potentials and the reconstruction of nutrient regimes. Changes in the fabric of the gastropod‐dominated beds are used to reconstruct a generally deepening environment...

The archaeocidarids comprise the most derived stem group echinoids and have long been regarded as closely related to the crown group. The fossil record of echinoids in the Palaeozoic is, however, poor, so details surrounding the initial divergence of crown group echinoids are not well constrained. In order to better understand the phylogenetic rela...

The end-Permian mass extinction (∼252 Ma) was responsible for high rates of extinction and evolutionary bottlenecks in a number of animal groups. Echinoids, or sea urchins, were no exception, and the Permian to Triassic represents one of the most significant intervals of time in their macroevolutionary history. The extinction event was responsible...

The multiplicity of cell types comprising multicellular organisms begs the question as to how cell type identities evolve over time. Cell type phylogenetics informs this question by comparing gene expression of homologous cell types in distantly related taxa. We employ this approach to inform the identity of larval skeletogenic cells of echinoderms...

Reconstructing the evolutionary assembly of animal body plans is challenging when there are large morphological gaps between extant sister taxa, as in the case of echinozoans (echinoids and holothurians). However, the inclusion of extinct taxa can help bridge these gaps. Here we describe a new species of echinozoan, Sollasina cthulhu, from the Silu...

A wealth of knowledge exists concerning echinoid substrate preference in recent and post-Paleozoic environments, however, relatively little is known of the environmental distribution and paleoecology of echinoids during the Paleozoic. The Paleozoic echinoids encompass the vast majority of the echinoid stem group, and were generally rare, but often...

Many of the most diverse clades of Late Palaeozoic echinoids (sea urchins) originated in the Devonian period. Our understanding of diversity dynamics of these Late Palaeozoic clades are thus informed by new systematic descriptions of some of their earliest members. The Proterocidaridae are a diverse and morphologically distinct clade of stem group...

We document a diverse ichnoassemblage from marine interbeds of the Lower Triassic terrestrial succession in the Houzhougongmiao (HZGM) section of Shaanxi Province, northwestern China. Integrated biostratigraphic data (bivalve, palynology and conchostracan) reveals that the ichnofossil-bearing marine beds are Griesbachian (Induan, Early Triassic) in...

The relative influences of extrinsic compared to intrinsic drivers of evolutionary change have long been theorized and debated in the fossil record. Ecological recoveries from mass extinction events present records in which to examine these contrasts. Competition in a low diversity world, reproductive strategy, reconstruction of trophic systems and...

Extinction and delayed recovery during the end-Permian extinction and Early Triassic has been linked to environmental instability brought on by volcanic outgassing and greenhouse conditions, but the relative importance of the myriad of environmental stressors at this time on recovery dynamics is not well understood. Previous workers have documented...

The echinoid fauna of the British Jurassic is one of the best-known faunas of that age globally, thanks to over one hundred and fifty years of work. Smith has provided, in his typical style, an excellent and much needed modern systematic treatment for the regular echinoids of the British Jurassic (the irregular echinoids were described by Barras, 2...

Paleozoic echinoids are exceptionally rare, and little is known of their paleoenvironmental distribution. The echinoid fauna of the Fort Payne Formation (Late Osagean, Early Viséan) of south-central Kentucky is documented. Four genera, ? Archaeocidaris , Lepidocidaris, ? Lepidesthes , and an unidentified lepidocentrid, were recovered and represent...

Articulated echinoids are rare in Palaeozoic strata. In order to gain a better understanding of palaeodiversity and community composition, it is more than useful to incorporate disarticulated specimens into estimates of such metrics. It has been demonstrated that disarticulated ossicles of echinoids from the post-Palaeozoic can be diagnostic at the...

Diverse sampling of organisms across the five major classes in the phylum Echinodermata is beginning to reveal much about the structure and function of gene regulatory networks (GRNs) in development and evolution. Sea urchins are the most studied clade within this phylum, and recent work suggests there has been dramatic rewiring at the top of the s...

A new species of the genus Archaeocidaris is described from the Marble Falls Formation of San Saba County, Texas, USA. This species, Archaeocidaris marmorcataractensis new species is the fourth species of Archaeocidaris described from relatively complete test material from the Pennsylvanian of North America. The test, spines and elements of the Ari...

Crinoids were relatively unaffected by the end-Devonian Hangenberg mass extinction event. Major clades of Devonian durophagous fishes suffered significant extinctions, however, and the dominant surviving clades were biting or nipping predators. In part as a response to the Hangenberg event, early Mississippian crinoids underwent an adaptive radiati...

Crinoid faunas from the Lower Devonian of South America are poorly known. Two new taxa are described from the Emsian Icla Formation at Cerro Kochis in the Cochabamba Department: the rhodocrinitid, Lutocrinus boliviaensis n. gen. n. sp. and Griphocrinus pirovanoi n. sp. Two additional camerates are reported from the Emsian Belèn Formation of the Alt...