Presumed postlarval pentacrinoids from the Lower Devonian Hunsrück Slate,Germany

Several tiny crinoids with crowns as small as 1 mm, or less, in width are newly recognized from the Hunsrück Slate of southwestern Germany. The presence of erect arms above an amorphous calyx in some specimens can be inferred. Based on comparison with the size and gross morphology of developmental stages in living crinoids, these tiny Hunsrück crinoids are judged to be at an early postlarval stage that is analogous to the pentacrinoid stage just after development from the stalked, but armless, smaller cystidean larval stage found in both living comatulids and isocrinids. Some of these tiny crinoids have a stalk up to 4 mm long attached to a now pyritized former substrate. Their clustered occurrence suggests gregarious settlement of larvae. Taxonomic identification of these presumed pentacrinoids is not possible, even to the sub‐class level, although they are preserved with larger juveniles of the cladids Propoteriocrinus and Lasiocrinus. These larger juveniles exhibit 3‐D pyritized calcite plates, whereas the probable pentacrinoids appear to be preserved as flattened, micro‐crystalline pyritized dermal tissues that enclosed lightly calcified, porous ossicles. The pentacrinoids were likely buried within weeks or months of hatching, based on developmental stages in similar‐sized living crinoids. These tiny crinoids, presumably pentacrinoids, are a further example of the extraordinarily detailed preservation of delicate tissues in pyrite from the Hunsrück Slate. They are most likely the pentacrinoid stage from one or more of the crinoid taxa (30 genera) present in the Hunsrück Slate. Assuming these are not microcrinoids, they are the first report of pentacrinoids from the fossil record and document that a Palaeozoic sister group to modern crinoids had similar developmental stages.     

Testing reduced evolutionary rates during the Late Palaeozoic Ice Age using the crinoid fossil record

In 2003, Stanley & Powell reported depressed rates of origination and extinction in marine invertebrates during the Late Palaeozoic Ice Age (LPIA). Using a database of crinoid genera, rates of origination, extinction and genus duration were calculated at the stage level from the Early Devonian to the Late Permian. This 165 m.y. time span includes non‐glacial intervals before and after the LPIA, which spanned the Serpukhovian to Sakmarian, providing background rates for comparison. Data generated on crinoid evolutionary rates during the Middle to Late Palaeozoic were analysed and compared to Stanley & Powell's data to determine whether crinoid evolutionary patterns support their findings or suggest an alternative hypothesis. Rates of origination and extinction in all crinoid clades were reduced during the LPIA compared to the combined background intervals before and after the LPIA. However, crinoid diversity was higher during the LPIA than the surrounding time intervals. The difference in diversity trends between crinoids and other marine invertebrates is due to the advanced cladids clade. Unstable, fluctuating environmental conditions during the LPIA may have created habitats suitable for opportunistic crinoid genera that reduced both the probability of origination and extinction. The increased diversity of the advanced cladids is likely due to their unique adaptation of muscular arm articulations, which allowed them to thrive in marine settings with increased siliciclastic influx brought on by the Alleghenian orogeny. Despite the advanced cladids’ departure from the expected diversity count, the results of analyses performed on the updated crinoid database provide independent confirmation of Stanley & Powell's original hypothesis of depressed evolutionary rates in marine invertebrates during the LPIA.     

Mississippian crinoid biodiversity,biogeography and macroevolution

Abstract: The biodiversity and biogeography of 217 genera of Mississippian crinoids from North America and the British Isles shed light on the macroevolutionary turnover between the Middle Palaeozoic and Late Palaeozoic Crinoid Evolutionary Faunas. This turnover resulted from steady differential extinction among clades during the middle Mississippian after crinoids reached their Phanerozoic peak of generic richness during the early Mississippian. This peak richness was primarily a function of Mississippian originations rather than Devonian–holdover taxa. North America had 100 per cent higher generic richness than the British Isles, but rarefaction analysis adjusts the difference to only 37 per cent higher. Rarefaction demonstrated that North America had increased biodiversity, compared to the British Isles, almost entirely among monobathrid camerates, disparids and primitive cladids. In contrast, diplobathrid camerates, advanced cladids and flexibles had the same generic biodiversity between regions, when compared using rarefaction. The early Mississippian radiation resulted from two primary causes: (1) the expansion of Tournaisian carbonate ramps following the Frasnian mass extinction of reef faunas and (2) the predatory release in the Tournaisian following the end‐Famennian Hangenberg extinction of durophagous fishes. A majority of crinoid genera from the British Isles are cosmopolitan. When combined with rarefaction analysis and evidence for more first occurrences in North America, this suggests higher origination rates in North America, especially when carbonate ramps were widespread. With the gradual reduction in the area of carbonate ramps from the early to late Mississippian, in conjunction with the radiation of new durophagous fishes, camerate crinoids in particular experienced continuous background extinction, without replacement, beginning during the earliest Viséan (late Osagean). By middle Viséan time (late Meramecian) advanced cladids were dominant in all settings. This resulted in the transition from the Middle Palaeozoic to the Late Palaeozoic Crinoid Macroevolutionary Fauna.     

Ontogeny and life-history strategy of Barycrinus (Crinoidea, Mississippian)

Discovery of an encrusting juvenile holdfast assigned to the Mississippian crinoid Barycrinus demonstrates that this stalked crinoid had a complex life history. The free-swimming larva settled to become a hard substratum encrusting juvenile, which broke free to become a free-living adult rooted into an unconsolidated substratum. Furthermore, additional small, encrusting holdfast types suggest that this was a common life-history strategy among Mississippian crinoids and, perhaps, blastoids.     

Phylogeny and evolutionary history of diplobathrid crinoids (Echinodermata)

Order Diplobathrida is a major clade of camerate crinoids spanning the Ordovician–Mississippian, yet phylogenetic relationships have only been inferred for Ordovician taxa. This has hampered efforts to construct a comprehensive tree of life for crinoids and develop a classification scheme that adequately reflects diplobathrid evolutionary history. Here, I apply maximum parsimony and Bayesian phylogenetic approaches to the fossil record of diplobathrids to infer the largest tree of fossil crinoids to date, with over 100 genera included. Recovered trees provide a framework for evaluating the current classification of diplobathrids. Notably, previous suborder divisions are not supported, and superfamily divisions will require significant modification. Although numerous revisions are required for families, most can be retained through reassignment of genera. In addition, recovered trees were used to produce phylogeny‐based estimates of diplobathrid lineage diversity. By accounting for ghost lineages, phylogeny‐based richness estimates offer greater insight into diversification and extinction dynamics than traditional taxonomy‐based approaches alone and provide a detailed summary of the ~150 million‐year evolutionary history of Diplobathrida. This study constitutes a major step toward producing a phylogeny of the Crinoidea and documenting crinoid diversity dynamics. In addition, it will serve as a framework for subsequent phylogeny‐based investigations of macroevolutionary questions.     

Tube foot preservation in the Devonian crinoid Codiacrinus from the Lower Devonian Hunsrück Slate,Germany

Fossilized tube feet are described on Codiacrinus schultzei Follmann from the Lower Devonian Hunsrück Slate of Germany. This is the first definitive proof of tube feet on any fossil crinoid. Three lightly pyritized, flattened tube feet are preserved in a single interray of this cladid crinoid. The tube feet were at least 7 mm long. Their preservation is very similar to the tube feet reported previously from a Hunsrück ophiuroid, except that the Codiacrinus tube feet have small papillae, similar to living crinoids.     

Regeneration,predatory–prey interaction,and evolutionary history of articulate crinoids

Regeneration and predatory–prey interaction of crinoids are reviewed. Crinoids have strong powers of regeneration, and arm regeneration is common in fossil and Recent crinoids. Regenerated arms commonly start from the ligamentary articulation called syzygy or cryptosyzygy, where crinoids can autotomize their arms. Therefore, regenerated arms can be formed after loss of arms by autotomy of arms, and such autotomy is commonly the response to predatory attacks. Thus, regenerated arms can be used as the clue to estimate the predatory frequencies. Regeneration of “correct” skeletal morphology as in the original depends on the existence of adoral nerve center. A stalk without the adoral nerve center cannot regenerate the “correct” morphology of the original skeleton, but forms of “callus” as skeletal overgrowth. The strong ability of regeneration is a key factor of the success of articulate crinoids in the geologic history since the Triassic onward.     

Epizoan encrustation on Marsupites testudinarius – additional argument favoring an epifaunal mode of life of uintacrinoids?

Uintacrinoids (Uintacrinoidea Zittel) are among the best-known Late Cretaceous crinoids, but owing to their unusual morphology and widespread distribution their mode of life has become a subject of much discussion. Of several competing hypotheses, nektonic, pseudoplanktonic, hemipelagic, semi-infaunal and epibenthic lifestyles have been suggested. Recent study synthesizing and extending previous data has shown that these crinoids were epibenthic, holding their arms vertically for feeding. However, evidence supporting a rheophilic epibenthic model over an alternative rheophobic semi-infaunal model is still limited. Here we report epizoans, mostly represented by serpulids and bryozoans, encrusting thecal plates of Marsupites testudinarius from the Lägerdorf in Germany. Although a definitive interpretation whether recorded infestations occurred syn vivo or post mortem is not certain, it is remarkable that all epizoans (or their traces) are attached to the convex side (latera) of well-preserved isolated plates displaying no signs of reworking. Furthermore, a bryozoan colony crossing plate boundaries has been also found on the surface of a sub-articulated theca suggesting that it may have been colonised syn vivo. Recorded epibiotic associations, whether syn vivo or post-mortem, must have developed prior to burial of the specimens, above the surface of sea floor, and thus provide another argument against rheophobic semi-infaunal mode of life of uintacrinoids.     

The genus Teliocrinus (Crinoidea,Echinodermata): a key taxon among pentacrinid stalked crinoids

The main characters of the stalked crinoids of the family Pentacrinitidae attributed to the genus Teliocrinus are re‐evaluated from a quantitative study of phenotype variation, new observations on arm and stalk articulations, and observation of ontogenetic trends. All of the specimens collected in the northern Indian Ocean belong to the same species, i.e. Teliocrinus springeri (Clark, 1909). However, two phenotypes living at different depths remain valid as subspecies: Teliocrinus springeri springeri (Clark, 1909) and Teliocrinus springeri liliaceus (Clark, 1909). Teliocrinus shares several ontogenetic trends with Endoxocrinus, especially in nonfunctional brachial articulations and stalk symplexies. Its assignment to the Diplocrininae is confirmed. A discussion of its affinities with pentacrinid fossil genera in which the crown is well preserved suggests that Diplocrininae could have first appeared during the Lower Cretaceous. A shortening of brachitaxes and a paedomorphic trend of stalk symplexies are the main other evolutionary traits. Nonfunctional articulations are frequently found at the paedomorphic pole of the heterochronic gradient, without clear derived characters. Classification of pentacrinids mainly based on such symplesiomorphy or paedomorphic characters must be definitively abandoned. However, in post‐Palaeozoic stalked crinoids the scarcity of well‐preserved fossils, the high frequency of paedomorphy, and convergent adaptive characters makes phylogenetic reconstruction only based on morphological characters very difficult and speculative. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 22–39.     

New crinoids from the Baltic region (Estonia): fossil tip‐dating phylogenetics constrains the origin and Ordovician–Silurian diversification of the Flexibilia (Echinodermata)

This study documents previously unknown taxonomic and morphological diversity among early Palaeozoic crinoids. Based on highly complete, well preserved crown material, we describe two new genera from the Ordovician and Silurian of the Baltic region (Estonia) that provide insight into two major features of the geological history of crinoids: the early evolution of the flexible clade during the Great Ordovician Biodiversification Event (GOBE), and their diversification history surrounding the end‐Ordovician mass extinction. The unexpected occurrence of a highly derived sagenocrinid, Tintinnabulicrinus estoniensis gen. et. sp. nov., from Upper Ordovician (lower Katian) rocks of the Baltic palaeocontinent provides high‐resolution temporal, taxonomic and palaeobiogeographical constraints on the origin and early evolution of the Flexibilia. The Silurian (lower Rhuddanian, Llandovery) Paerticrinus arvosus gen. et sp. nov. is the oldest known Silurian crinoid from Baltica and thus provides the earliest Baltic record of crinoids following the aftermath of the end‐Ordovician mass extinction. A Bayesian ‘fossil tip‐dating’ analysis implementing the fossilized birth–death process and a relaxed morphological clock model suggests that flexibles evolved c. 3 million years prior to their oldest fossil record, potentially involving an ancestor–descendant relationship (via ‘budding’ cladogenesis or anagenesis) with the paraphyletic cladid Cupulocrinus. The sagenocrinid subclade rapidly diverged from ‘taxocrinid’ grade crinoids during the final stages of the GOBE, culminating in maximal diversity among Ordovician crinoid faunas on a global scale. Remarkably, diversification patterns indicate little taxonomic turnover among flexibles across the Late Ordovician mass extinction. However, the elimination of closely related clades may have helped pave the way for their subsequent Silurian diversification and increased ecological role in post‐Ordovician Palaeozoic marine communities. This study highlights the significance of studies reporting faunas from undersampled palaeogeographical regions for clade‐based phylogenetic studies and improving estimates of global biodiversity through geological time.     

A new holocrinid (Articulata) from the Paris Biota (Bear Lake County,Idaho, USA) highlights the high diversity of Early Triassic crinoids

After the end-Permian crisis and the extinction of their four Paleozoic subclasses, crinoids rapidly recovered. This group is classically believed to have radiated from a small surviving clade and to have diversified during the Middle and Upper Triassic from two lineages. Nevertheless, recent findings suggested that several lineages of crinoids had already diversified during the Early Triassic, and that their diversity has been overlooked. Here we describe a new form of holocrinid, Holocrinus nov. sp., from the earliest Spathian (Early Triassic) of southeastern Idaho (USA). So far, the exceptional completeness of sampled specimens, with skeletal elements of arms and stem in connection, is unique for the Early Triassic. They show that derived morphological features had already evolved ∼1.3 million years after the Permian–Triassic boundary, supporting the scenario of a rapid Early Triassic diversification of crinoids.     

New data on the distribution of the Upper Carboniferous (Pennsylvanian) flexible crinoid Cibolocrinus (Crinoidea,Flexibilia)

Two new species of flexible crinoids of the genus Cibolocrinus (Crinoidea, Flexibilia) from the Upper Carboniferous of the Moscow Region are described: C. kutasovi (Moscovian Stage, Podolskian Regional Substage) and C. gerassimovi (Gzhelian Stage, Dobryatinian Regional Substage). The first species, C. kutasovi, belongs to a group with low cone shaped cups that first appeared in the Moscow Basin and then spread to the Midcontinent of North America. In one specimen of C. gerassimovi the smallest infrabasal plate is situated in the A ray, which is not typical for flexible crinoids. A poorly preserved crown of Cibolocrinus sp. from the Upper Carboniferous (Gzhelian Stage) of the Darvaz Ridge (western Pamir, central Tajikistan) is also described. The described specimens of Cibolocrinus from the Moscow Region and the Darvaz Ridge are the first reliable specimens of this genus described from Europe and Asia.     

Records of echinoderms (excluding holothurians) from the Norfolk Ridge and Three Kings Rise north of New Zealand

Abstract

Fifty-eight species of echinoderms (excluding holothurians) are newly recorded from the southern Norfolk Ridge and the Three Kings Rise to the north of New Zealand. Two species of Asteroidea, in the genera Ceramaster and Pseudoceramaster, ceramaster are described as new. A total of 115 species of echinoderms, not counting the holothurians, are now known from this area. They include 14 crinoids, 35 asteroids, 41 ophiuroids, and 25 echinoids.     

Circumpolar dataset of sequenced specimens of Promachocrinus kerguelensis (Echinodermata,Crinoidea)

This circumpolar dataset of the comatulid (Echinodermata: Crinoidea) Promachocrinus kerguelensis (Carpenter, 1888) from the Southern Ocean, documents biodiversity associated with the specimens sequenced in Hemery et al. (2012). The aim of Hemery et al. (2012) paper was to use phylogeographic and phylogenetic tools to assess the genetic diversity, demographic history and evolutionary relationships of this very common and abundant comatulid, in the context of the glacial history of the Antarctic and Sub-Antarctic shelves (Thatje et al. 2005, 2008). Over one thousand three hundred specimens (1307) used in this study were collected during seventeen cruises from 1996 to 2010, in eight regions of the Southern Ocean: Kerguelen Plateau, Davis Sea, Dumont d’Urville Sea, Ross Sea, Amundsen Sea, West Antarctic Peninsula, East Weddell Sea and Scotia Arc including the tip of the Antarctic Peninsula and the Bransfield Strait. We give here the metadata of this dataset, which lists sampling sources (cruise ID, ship name, sampling date, sampling gear), sampling sites (station, geographic coordinates, depth) and genetic data (phylogroup, haplotype, sequence ID) for each of the 1307 specimens. The identification of the specimens was controlled by an expert taxonomist specialist of crinoids (Marc Eléaume, Muséum national d’Histoire naturelle, Paris) and all the COI sequences were matched against those available on the Barcode of Life Data System (BOLD: http://www.boldsystems.org/index.php/IDS_OpenIdEngine). This dataset can be used by studies dealing with, among other interests, Antarctic and/or crinoid diversity (species richness, distribution patterns), biogeography or habitat / ecological niche modeling. This dataset is accessible through the GBIF network at http://ipt.biodiversity.aq/resource.do?r=proke.     

NEW CRINOIDS (ECHINODERMATA) FROM THE LLANDOVERY (LOWER SILURIAN) OF THE BRITISH ISLES

Abstract:  British Llandovery crinoids remain poorly known. Three species are documented herein that were originally described, but not published, by W. H. C. Ramsbottom. Clematocrinus ramsbottomi Fearnhead sp. nov. (Tortworth Inlier, Gloucestershire; Telychian) has a heteromorphic column, N434243414342434, radices directed away from the crown, and ten long, uniserial arms with a pustular aboral sculpture and long, slender pinnules. Clematocrinus spp. are widely distributed in the Silurian of England. Ptychocrinus mullochillensis Fearnhead and Donovan sp. nov. (Girvan district, Strathclyde; Rhuddanian) is the second report of this Upper Ordovician–Lower Silurian genus from outside North America. Although incompletely known, this species is distinguished by its hidden infrabasals, 20 arms and sunken interbrachial plates with a strongly stellate sculpture. Petalocrinus bifidus (Bather MS) Donovan and Fearnhead sp. nov. (Woolhope Inlier, Herefordshire; Telychian) is locally common enough to give its name to a mappable lithostratigraphic unit, the Petalocrinus Limestone. Unlike other Petalocrinus species known from the Silurian of China, northern Europe and North America, the fused arms of P. bifidus are divided in two by a proximal adoral ridge and an associated distal notch. Unlike extant crinoids, Petalocrinus probably lived as a rheophobe; the fused arms may have acted to deter predators.     

Revision of Strunian crinoids and blastoids from Germany

In 1930W.E. Schmidt described all known crinoids from the German Early Carboniferous, including the Etroeungt beds of Germany, which are now judged to be latest Devonian (Famennian) in age. On a global basis, Famennian camerate crinoids generally show a closer relationship to succeeding Early Carboniferous faunas than they do to older Frasnian or Middle Devonian crinoids, which also is the case for the Strunian fauna. Holdovers from older Devonian faunas include, among others,Adelocrinus, a descendant of olderArthroacantha, in England and Germany, andPetaloblastus, which is one of the youngest genera of the blastoid family Hyperoblastidae. Precursors of younger Early Carboniferous groups include platycrinoids, primitive actinocrinoids, dichocrinoids, and the blastoid genusDoryblastus, which is one of the oldest members of the family Orbitremitidae. All of these groups, which became important parts of the Early Carboniferous crinoid and blastoid radiation, give Famennian crinoid faunas much more of an Early Carboniferous than a Devonian aspect. Rhipidocrinus schmidti n. sp. is erected for specimens that originally were reported from the Etroeungt asRhodocrinus uniarticulatus. We judge that there are currently four valid species assigned toRhipidocrinus: R. crenatus, R. perloricatus, R. praecursor, and our new species,R. schmidti. Hydriocrinus ratingensis Schmidt is reassigned to ?Sostronocrinus. We note thatSchmidt (1906), notJaekel (1906) as has been reported previously, is the author ofRhipidocrinus perloricatus. Owing to the poor preservation of the Etroeungt material, we regard the namePlatycrinites wunstorfi Schmidt 1930 to be a nomen nudum.     

Hrabalicrinus zitti gen. et sp. nov., and other Upper Jurassic crinoids (Echinodermata,Crinoidea) from the Brno area (Czech Republic)

Jurassic (Oxfordian) crinoids from the Brno area (Czech Republic) are described in details for the first time. A rich crinoid assemblage consisting of cups, isolated cup elements, brachial plates, columnals, pluricolumnals, and cirrals is assigned to isocrinids Isocrinus amblyscalaris (Thurmann), Balanocrinus subteres (Münster), B. pentagonalis (Goldfuss), Isocrinida indet., comatulid Hrabalicrinus zitti gen. et sp. nov., cyrtocrinids Lonchocrinus sp., Cyrtocrinus cf. nutans (Goldfuss), Pilocrinus moussoni (Desor), Tetracrinus moniliformis Münster, Cyrtocrinida indet., and millericrinids (Millericrinida indet.). Crinoids already mentioned from the Jurassic strata of the Czech Republic are subsequently revised. Apart from the isolated remains of Isocrinida, Millericrinida, and Thiolliericrinida, the presence of any other taxon reported from this area should be treated with extreme caution. A rare example of non-regenerative columnal healing (the so-called callus) in I. amblyscalaris is also described. Based on sedimentology and microfacies, the Jurassic limestones were deposited in various palaeoenvironments of upper carbonate platform and shelf lagoon (0 to > 50 m palaeodepth).     

Trends in the sand: Directional evolution in the shell shape of recessing scallops (Bivalvia: Pectinidae)

Directional evolution is one of the most compelling evolutionary patterns observed in macroevolution. Yet, despite its importance, detecting such trends in multivariate data remains a challenge. In this study, we evaluate multivariate evolution of shell shape in 93 bivalved scallop species, combining geometric morphometrics and phylogenetic comparative methods. Phylomorphospace visualization described the history of morphological diversification in the group; revealing that taxa with a recessing life habit were the most distinctive in shell shape, and appeared to display a directional trend. To evaluate this hypothesis empirically, we extended existing methods by characterizing the mean directional evolution in phylomorphospace for recessing scallops. We then compared this pattern to what was expected under several alternative evolutionary scenarios using phylogenetic simulations. The observed pattern did not fall within the distribution obtained under multivariate Brownian motion, enabling us to reject this evolutionary scenario. By contrast, the observed pattern was more similar to, and fell within, the distribution obtained from simulations using Brownian motion combined with a directional trend. Thus, the observed data are consistent with a pattern of directional evolution for this lineage of recessing scallops. We discuss this putative directional evolutionary trend in terms of its potential adaptive role in exploiting novel habitats.     

Multiphase morphospace saturation in cyrtocrinid crinoids

The study of the relationship between disparity (occupied morphospace) and diversity (number of taxa) through geological time represents a powerful tool in the macroevolutionary study of groups. In this contribution, this approach is applied for the first time to the cyrtocrinid crinoids, a major clade of mostly Mesozoic articulate crinoids also represented by rare Cenozoic forms (two extant taxa). The analysis of disparity identified two separate evolutionary radiations for cyrtocrinids with maximum morphospace exploration, one at the beginning of the evolutionary history of the group in the Pliensbachian and a second one between the Late Jurassic and Early Cretaceous. On the methodological level, the disparity measured both as total variance and as sum of ranges shows compatible results, with trends well coupled to the diversity curve indicating that, in cyrtocrinid crinoids, an increase or decrease in the number of taxa in the history of the clade corresponds a proportional increase and decrease also in the occupied morphospace. The curves obtained were interpreted in the light of the clade's phylogeny, major oceanographic events, newly available ecological niches and relative key innovations, which would be able to increase the fitness of the group. The group diversity was already in decline starting from the Aptian, and the mass extinction at the K‐PG boundary had no effect on the history of the clade. The results show once again the importance and potential of diversity/disparity studies when put into the light of palaeotectonic, palaeoecological and palaeoenvironmental factors.     

Early phylogeny of crinoids within the pelmatozoan clade

Phylogenetic relationships among early crinoids are evaluated by maximizing parsimonious‐informative characters that are unordered and unweighted. Primarily Tremadocian–Darriwilian (Early–Middle Ordovician) taxa are analysed. Stratigraphic congruence metrics support the best phylogenetic hypothesis derived using parsimony methods. This study confirms the traditionally recognized lineages of Palaeozoic crinoids and provides new information on the branching order of evolving lineages. Camerates are basal crinoids with progressively more tipward groups (from an Ordovician perspective) being protocrinoids, cladids (paraphyletic), hybocrinids and disparids. The Protocrinoida should be maintained, but the Aethocrinida should be placed within the Cladida. The results of this study identify phylogenetic structure amongst the major early crinoid lineages and delineate the relative positions of crinoid higher taxa along a tree. Each valid higher taxon discussed herein requires a comprehensive treatment to delimit within‐lineage phylogenetic relationships.