Crinoid Fauna Research Articles

A crinoid fauna and a new species of Pycnocrinus from the Martinsburg Formation (Upper Ordovician), lower Hudson Valley, New York

Abstract A new crinoid fauna has been discovered in the Upper Ordovician (Katian) Martinsburg Formation at a small shale quarry, locally known as the ‘Shale Bank,’ on the Shawangunk Ridge in Ulster County, NY. The assemblage, which is from a relatively low energy, offshore mud-bottom environment, includes four identified species, including a new species of glyptocrinid camerate, Pycnocrinus mohonkensis n. sp., described herein. Crinoid taxa in order of increasing branch density in the assemblage include (1) the dicyclic inadunate Merocrinus curtus with irregularly isotomous and heterotomous, non-pinnulate arms and a stout cylindrical column exceeding 700 mm; (2) the disparids Cincinnaticrinus varibrachialus, with heterotomous non pinnulate arms, and Ectenocrinus simplex, with extensively branched ramulate arms and meric columns of 460–500 mm; and (3) the camerate Pycnocrinus mohonkensis n. sp., with uniserial pinnulate arms and a somewhat shorter column. Some cylindrical stems with nodose and holomeric columnals are thought to belong to unknown camerate crinoids with pinnulate arms. Filtration theory is used to model food capture in the Martinsburg crinoids. Surprisingly, even densely pinnulate camerates were able to survive in this setting, suggesting that ambient currents attained velocities exceeding 25 cm/sec even in this offshore setting. Similar assemblages were widespread in eastern Laurentia during the Late Ordovician. UUID: http://zoobank.org/23ca31e8-f572-4520-ba1d-891e3abb950d

Crinoids from the Wooster Shale Member of the Cuyahoga Formation, Carboniferous (Mississippian, Tournaisian) of northeastern Ohio

AbstractNine crinoids are described from the Wooster Shale Member of the Cuyahoga Formation from Wayne and Ashland counties, Ohio, USA. Identifiable elements of the fauna include five camerate crinoids, one flexible crinoid, and three other eucladid crinoids. Five new species are described, includingCactocrinus woosterensisn. sp.,Cusacrinus brushin. sp.,Agaricocrinus murphyin. sp.,Decadocrinus laevisn. sp., andDecadocrinus inordinatusn. sp. Overall, the distribution of crinoid clades in the Wooster Shale is similar to that of the stratigraphically lower Meadville Shale Member of the Cuyahoga Formation, although less diverse and with only one species (Cyathocrinites simplex) in common. Many of the Wooster Shale Member crinoids are completely or partially preserved with siderite either in nodules or within siderite beds. These crinoids are commonly preserved in trauma postures, which is characteristic of burial in episodic high turbulence events. The paleoenvironments and taxa of the two Cuyahoga Formation crinoid faunas more closely resemble Viséan faunas in siliciclastic settings than typical carbonate faunas of the Tournaisian.UUID:http://zoobank.org/2d2678e1-2367-4429-bea0-a64cd020e98c

Mooreocrinus liaoi sp. nov. (Crinoidea, Echinodermata) from the Pennsylvanian (Upper Carboniferous) Outangdi Formation in Zhejiang, South China Block

A new crinoid species of the Order Cladida, Mooreocrinus liaoi Mao and Li sp. nov., is described from the Pennsylvanian (Upper Carboniferous) Outangdi Formation in Jiangshan, Zhejiang Province, representing the first record of Mooreocrinus Wright and Strimple, 1945 in China. The presence of Mooreocrinus in the South China Block extends the palaeogeographical record of this genus and indicates it to be a cosmopolitan taxon. Three other ancient tectonically separated areas that are now combined into the modern China mass (Sibumasu, Junggar, North China) do not contain any record of Mooreocrinus. Overall, there is low biodiversity of the Late Palaeozoic crinoid faunas in the South China Block. Our new materials provide further evidence for diversity assessment of crinoid faunas in peri‐Gondwana blocks.

Evolutionary and taphonomic implications of a new species of Amphoracrinus from the early Viséan of Kentucky

AbstractThe youngest species of Amphoracrinus, A. tenax new species, is described from the Muldraugh Member of the Borden Formation (early Viséan) of north-central Kentucky. With this new occurrence, both the oldest and youngest named species of Amphoracrinus are from North America. Numerous Tournaisian and Viséan crinoid faunas are documented in the United States, but only four are known to contain Amphoracrinus. Morphological analysis indicates that A. tenax is more closely aligned with species from China than with species from Western Europe or other species from North America, where Amphoracrinus was most diverse and abundant, which has implications for understanding paleogeographic dispersal. The holotype of A. tenax was partially disarticulated on the seafloor before burial, and final burial occurred early during disarticulation. The relative state of disarticulation from pinnules to columnals suggests that plates bound only with ligaments disarticulated as a function of surface area of ligaments binding an articulation.UUID: http//zoobank.org/c7faf06e-bdd1-43a2-8c10-1364a0aeae0d

Catalogue of living crinoids (Echinodermata: Crinoidea) from Brazil.

Knowledge of living crinoids from Brazil is chiefly restricted to the contributions of Dr Luis Roberto Tommasi between the decades of 1950 and 1970. Herein we present an updated catalogue of the crinoids occurring along the Brazilian coast, including data on synonyms, type localities, type material, geographical distribution, bathymetric ranges, and occurrences of species along the coast. The data is based on an extensive revision of the literature and on a survey of several databases. A total of 20 species were catalogued, of which two are endemic (Phrixometra longipinna var. brasiliensis and Thaumatometra minutissima). According to information from the literature, P. longipinna var. brasiliensis represents an undescribed taxon. Although Brazil supports the greatest number of crinoid species in the Southwestern Atlantic, its crinoid fauna remains understudied and likely underestimated. Research on crinoids remains a subject of great potential, not only for taxonomy but also for other areas of knowledge.

A diverse crinoid fauna (Echinodermata, Crinoidea) from the Lower Eocene of the Gulf of Languedoc (Corbières, Aude, southern France)

Detailed studies of the middle Ilerdian (lower Ypresian) blue marls of the Gulf of Languedoc (Corbières, Aude, France), belonging to the north Pyrenean foreland basin, have revealed a more abundant and diverse crinoid fauna than previously documented from the Lower Eocene. Here we describe five species of stalked crinoids in the family Rhizocrinidae (Cherbonniericrinus requiensis n. sp., ?Democrinus elongatus, Globulocrinus amphoraformis n. gen., n. sp., Pseudoconocrinus doncieuxi and P. lavadensis n. sp.), one barnacle-like species in the stalkless family Holopodidae (Holopus plaziati n. sp.) and a single feather star in the family Conometridae (Amphorometra atacica). Several sites have yielded brachials and rhizoids in addition to abundant aboral cups and columnals indicating in situ fossilisation of the dissociated skeletal elements. P. lavadensis n. sp. and ?D. elongatus have been collected only from outcrops located in the upper part of the middle blue marls, while P. doncieuxi predominates, with a wide range of morphological variation, in the lower blue marls. The fossil assemblage at the locality of Réqui near Montlaur differs from the others in the smaller size of most individuals and the presence of H. plaziati n. sp., C. requiensis n. sp., G. amphoraformis n. gen., n. sp., and P. doncieuxi suboblongus n. subsp. This particular association with high juvenile mortality corresponds to an unstable environment with mixed substrates (muddy and rocky). The crinoid fauna of the Corbières appears to be the most diverse of Early Eocene age known to date. With the fauna of the London Clay, a boreal formation of the same age, it shares the presence of the genera Democrinus and Amphorometra in an open-sea environment. A comparison with extant faunas allows the depth of deposition at the Ypresian sites in the Gulf of Languedoc to be estimated between from 100 and 140 meters.

A Hirnantian holdover from the Late Ordovician mass extinction: phylogeny and biogeography of a new anthracocrinid crinoid from Estonia

AbstractRelatively few Hirnantian (Late Ordovician) crinoids are known, and none has been previously described from the palaeocontinent of Baltica. This has impaired our ability to understand the patterns of extinction and biogeographic dispersal surrounding the Late Ordovician mass extinction, which triggered a major turnover in crinoid faunas. Here, we describe Tallinnicrinus toomae gen. et sp. nov., an anthracocrinid diplobathrid from the Hirnantian of northern Estonia. Tallinnicrinus is the youngest member of the Anthracocrinidae and the first representative of the family to occur in Baltica. Morphologically, Tallinnicrinus is unusual in that the radial and basal plates are in a single circlet of 10 plates, similar to the anthracocrinid Rheocrinus Haugh, 1979 from the Katian of Laurentia. Phylogenetic analysis further confirms a close relationship between Tallinnicrinus and Laurentian anthracocrinids, suggesting biogeographic dispersal of the lineage from Laurentia to Baltica during the late Katian or early Hirnantian. The occurrence of this new taxon establishes that the family Anthracocrinidae survived the first pulse of the Late Ordovician mass extinction. However, the lineage remained a ‘dead clade walking’ because it failed to diversify in the wake of the end‐Katian extinction and ultimately went extinct itself by the end of the Ordovician.

The Hushoot Shiveetiin gol section (Baruunhuurai Terrane, Mongolia): sedimentology and facies from a Late Devonian island arc setting

A Late Devonian to (?)Early Mississippian section at Hushoot Shiveetiin gol in the Baruunhuurai Terrane of the Central Asian Orogenic Belt (CAOB) exposes large parts of cyclic Famennian shallow-water siliciclastic shelf deposits composed of siltstones, sandstones, shales, volcaniclastics, and intercalated autochthonous carbonates. The youngest part of the section, possibly Early Mississippian, is represented by arkosic sandstones with large plant remains. The facies reflects a range from shallow-intertidal to outer ramp settings. In terms of conodont stratigraphy, the Hushoot Shiveetiin gol section ranges from the Palmatolepis minuta minuta Biozone to at least the Palmatolepis rugosa trachytera Biozone. Hiatuses of several conodont biozones occur due to the facies setting (erosion and reworked sediments which are recognized by reworked conodonts) rather than thrusting or folding. The environmental setting was characterized by coeval subaerial volcanism resulting in numerous pyroclastic deposits. The depositional environments and intense volcanic activity at the Hushoot Shiveetiin gol section limited the stratigraphic distribution, abundance, and diversity of many elements of the fauna such as brachiopods. Ostracods were very abundant and diverse through many parts of the section. Although limited in stratigraphic distribution, the crinoid fauna is the most diverse Palaeozoic fauna collected from Mongolia to date and supports the hypothesis that the CAOB was a biodiversity hotspot in the aftermath of the Frasnian–Famennian extinction event.

Crinoids from the Lower (Pragian–Emsian) and Middle (early Eifelian) Devonian of Bolivia (Icla and Belén formations, Malvinokaffric Realm)

AbstractTwo new families and three new genera and species of Crinoidea from the Icla and Belén formations, Bolivian Devonian, are described. The material is identified asMeperocrinus angelinan. gen. n. sp., from the Icla Formation of the Sub-Andina region,Tuberocrinus lapazensisn. gen. n. sp. andAenigmaticumcrinus rochacamposin. gen. n. sp., both from the Belén Formation of the Bolivian Altiplano.Meperocrinus angelinan. gen. n. sp. is an Emperocrinidae, a family described from the Silurian of the United States of America.Tuberocrinus lapazensisn. gen. n. sp. is assigned to a new family of Dimerocrinitacea, the Tuberocrinidae n. fam., which is closely related to Pterinocrinidae that already has representatives in Bolivia (Apurocrinus sucreiMcIntosh), Argentina (Pterinocrinus?australisHaude), and Colombia (Bogotacrinus scheibeiMcIntosh).Aenigmaticumcrinus rochacamposin. gen. n. sp. is also as assigned to a new family of Dimerocrinitacea, the Aenigmaticumcrinidae n. fam.; a family with very distinctive features. These data demonstrate that the Malvinokaffric crinoid fauna in Bolivia has a mixed origin, with forms that arrived in South America from Europe (Old World Realm) and United States of America (Eastern America Realm) during the late Silurian or earliest Devonian, as well as a local stock, which evolved to highly endemic lineages.UUID:http://zoobank.org/f03120c6-264a-4ae9-81e0-46bfe844e65e.

The Shallow-water Crinoid Fauna of Lakshadweep Atolls, North-western Indian Ocean.

A biodiversity survey carried out from 2016 to 2018 by the Department of Science and Technology in the Lakshadweep Atolls, India, recorded six species of shallow-water feather stars new to the archipelago (Comanthus wahlbergii, Comaster schlegelii, Himerometra robustipinna, Dichrometra palmata, Stephanometra indica, and Phanogenia typica). Himerometra sol A.H. Clark, 1912, previously known only from the Maldive Islands, is synonymized under Himerometra robustipinna (Carpenter, 1881). This study brings the total number of shallow-water crinoids recorded from Lakshadweep to ten species. Of the four species collected previously from the archipelago, only Comatella nigra was found in this survey. Of those not collected, Comatella stelligera and Oligometra serripinna are widespread in the Indo-western Pacific region, whereas Heterometra compta is known only from Lakshadweep, and its validity remains uncertain. The known shallow-water crinoid fauna of the archipelago is substantially less diverse than that of the adjacent and environmentally similar Maldive Islands, emphasizing the need for additional research in this island group, in particular, to determine whether the differences are actual or not, and whether they are based on natural conditions versus anthropogenic impacts.

Paleocommunity composition, relative abundance, and new camerate crinoids from the Brechin Lagerstätte (Upper Ordovician)

AbstractThe Brechin Lagerstätte of southern Ontario contains an exceptionally diverse and well-preserved Late Ordovician (Katian) crinoid fauna. We describe four genera and eight species of camerate crinoids from the Brechin Lagerstätte, including six new species. Consequently, the total diversity of the fauna now stands at 27 genera and 39 nominal species, thereby making it the most taxonomically diverse Ordovician crinoid fauna known. Taxa described include the diplobathrid Pararchaeocrinus kiddi new species and the monobathrids Glyptocrinus ramulosus Billings, 1856, Periglyptocrinus priscus (Billings, 1857a), Periglyptocrinus astricus new species, Periglyptocrinus kevinbretti new species, Periglyptocrinus mcdonaldi new species, Periglyptocrinus silvosus new species, and Abludoglyptocrinus steinheimerae new species. We summarize the taxonomic composition, diversity, and abundance distribution of all known crinoids from the Brechin Lagerstätte to better characterize the paleoecological structure and complexity of the community. We establish that the fauna is dominated by the subclass Pentacrinoidea, both in terms of abundance and species richness. In addition, we analyze species-level abundance data using Relative Abundance Distribution (RAD) models to evaluate the ecological complexity of the paleocommunity. We found that community structure of the Brechin Lagerstätte is best explained by an ecologically ‘complex’ RAD model, which suggests that species partitioned niches along multiple resource axes and/or the presence of multiple ecological ways of life. These results indicate that the Brechin Lagerstätte is significant not only for being the most taxonomically diverse Katian crinoid assemblage, but also for being an early ecologically complex fauna that developed in the wake of the Great Ordovician Biodiversification Event.UUID: http://zoobank.org/f86582ed-5db6-469E-befe-34b801f9a113

Taphonomic Implications of a Crinoid from Echinoderm-Poor Lithofacies in the Upper Ordovician (Katian: Cincinnatian) of Northern Kentucky

Crinoids (Phylum Echinodermata) represent major components of fossil assemblages in the type Cincinnatian (Upper Ordovician: Katian) of the greater Cincinnati Arch region. However, certain shallow marine lithofacies are characterized by a nonexistent to depauperate crinoid fauna, being instead dominated by trilobites, bryozoans, mollusks, and in some layers solenoporid algae? and stromatoporoids. One such setting is represented by the Grant Lake Formation, equivalent to the upper Corryville and Mount Auburn members of the McMillan Formation of Ohio, as exposed south of Flemingsburg, Fleming County, northern Kentucky. Described herein is an articulated crinoid crown (Anomalocrinus?) from this otherwise crinoid-poor interval. This occurrence may reflect either (1) a brief interval where conditions were more amenable to occupation by crinoids, possibly corresponding to a minor flooding surface, or (2) transportation of skeletal remains from nearby, deeper offshore areas that contained crinoids in greater abundance. The second interpretation seems more likely given the absence of in situ attachment structures and rarity of disarticulated column material at the study site. This study illustrates the value of echinoderm remains in paleoenvironmental analysis, the significance of crinoidal material in taphonomic interpretation of Paleozoic argillaceous carbonate deposits, and the sensitivity of crinoid fossils as indicators of allochthony or autochthony.

New taxa and revised stratigraphic distribution of the crinoid fauna from Anticosti Island, Québec, Canada (Late Ordovician-early Silurian)

AbstractEnd-Ordovician extinctions had a profound effect on shallow-water benthic communities, including the Crinoidea. Further, recovery after the extinctions resulted in a macroevolutionary turnover in crinoid faunas. Anticosti Island is the most complete Ordovician-Silurian boundary section recording shallow-water habitats. Both new taxa and changes in Anticosti Island stratigraphic nomenclature are addressed herein. New taxa includeBecsciecrinus groulxin. sp.,Bucucrinus isotaloin. sp.,Jovacrinus clarkin. sp.,Plicodendrocrinus petrykin. sp.,Plicodendrocrinus martinin. sp.,Thalamocrinus daoustaen. sp., andLateranicrinus saintlaurentin. gen. n. sp. The status ofXenocrinus rubusas a boundary-crossing taxon is confirmed, range extensions of several taxa are documented, and the distribution of crinoids with the revised stratigraphic nomenclature is documented.UUID:http://zoobank.org/19613a44-ec69-47d7-88ab-fcf88ba771f0.

Stratigraphic and paleogeographic distributions of Devonian crinoids from Spain with description of new taxa from the Iberian Chains

AbstractA new Lower Devonian fauna from the Iberian Chains (NE Spain) is described. Specimens have been collected from the shaley intervals of the Mariposas Formation dated as early Emsian. These include the camerates Acanthocrinus carsli n. sp., Platyhexacrinus santacruzensis n. sp., Culicocrinus breimeri n. sp., Camerata indeterminate, and an indeterminate eucladid. Compared with other faunas from Spain, this represents a low diversity crinoid assemblage that was probably concentrated in shallow, turbid environments. A summary of crinoids previously described from the Spanish Devonian is reported, which indicates that crinoid faunas become progressively more cosmopolitan during the Devonian.UUID: http://zoobank.org:pub/2debf9fa-11bf-46df-baf1-ab7926031051

Phylogenetic community paleoecology of one of the earliest complex crinoid faunas (Brechin Lagerstätte, Ordovician)

Integrating phylogenetic biology with paleoecology can provide a valuable context for understanding patterns of community structure and niche partitioning in ancient ecosystems. However, the lack of robust phylogenies for many fossil taxa precludes studies of this nature, particularly among marine invertebrates. Fossil Crinoidea (Echinodermata) comprise an ideal model system for phylogenetic community paleoecology for three reasons: (1) they preserve anatomical features that directly relate to feeding ecology, (2) assemblages of well-preserved specimens represent “ecological snapshots” in time, and (3) recent advances in resolving the crinoid tree of life have produced high-resolution phylogenies for Ordovician lineages. Here, we apply multivariate and phylogenetic comparative methods to investigate patterns of paleocommunity structure, niche partitioning, and ecomorphospace occupation in one of the earliest known complex crinoid paleocommunities, the Brechin Lagerstätte (Upper Ordovician, Katian). Results indicate niche differences among species were determined primarily by characters related to filtration fan morphology. Filtration fan density and body size distributions support phylogenetic niche conservatism, but traits related to the size of the feeding area are more labile and exhibit greater divergence than expected among closely related species. Finally, we compare changes in the shape and phylogenetic structure of niche distributions between the Brechin Lagerstätte and the Edwardsville crinoid fauna, a well-studied Mississippian (Viséan) paleocommunity, to examine patterns of community change across the Early to Middle Paleozoic Crinoid Macroevolutionary Faunas.

Mississippian–Permian evolution and paleogeographic distribution of the Cromyocrinidae and Pirasocrinidae (Crinoidea, Dendrocrinida)

Late Paleozoic macroevolutionary crinoid faunas were dominated by dendrocrinids, replacing most of the camerata crinoids that had dominated the Early and Middle Paleozoic macroevolutionary crinoid faunas. Two dendrocrinid taxa, the Cromyocrinidae and Pirasocrinidae, first recognized in the Mississippian (Visean), attained their greatest generic diversity in the late Moscovian to early Kasimovian, declined in the Late Pennsylvanian and Early Permian, and became extinct in the Late Permian or end-Permian extinction event. The paleontologic record of the Cromyocrinindae and Pirasocrinidae is best documented from the Midcontinent of the United States and both are recognized worldwide in the Late Paleozoic. Their diversity in the latest Pennsylvanian and Early Permian is probably greater than currently recognized because disarticulated ossicles that are ascribed to one or the other of the two families in described faunas are commonly not recognizable at the genus level. Both families show individual evolutionary trends while following the general evolutionary trends of the dendrocrinids.

Late Ordovician crinoids from the Anti-Atlas region of Morocco

Abstract The crinoid fauna of the Late Ordovician (Sandbian and Katian) of Morocco is sparse, but diverse. The one previously described species, Rosfacrinus robustus Le Menn & Spjeldnaes, 1996 , is now known to be part of an assemblage of at least 10 species, including the new taxa Iocrinus ouzammoui sp. nov. (Disparida), Superlininicrinus advorsa gen. et sp. nov., Isthloucrinus praecursor gen. et a sp. nov. (Cladida) and Euptychocrinus ? atelis sp. nov. (Camerata). The fauna also includes an additional species of Iocrinus , and several camerates including Trichinocrinus sp. and a monobathrid with probable affinities to the Tanaocrinidae. Undeterminable specimens of demonstrably different taxa are described as far as possible. The fauna includes genera previously known from Laurentia and Avalonia, implying unexpected latitudinal dispersal, together with evidence for substantial endemic diversification among cladids and camerates. Several of the taxa have unusual plate arrangements, including a mosaic of primitive and derived characters; this implies that early crinoid diversification was not limited to tropical carbonate facies. The fauna remains poorly known, with low numbers of specimens, and future collecting is likely to increase the diversity significantly.

A new crinoid fauna from the Taiyuan Formation (early Permian) of Henan, North China

AbstractA diverse Permian crinoid fauna is reported from the Taiyuan Formation, Dajian Member (Asselian) at Anyang, northeastern Henan Province of the North China Craton. The specimens are well preserved, including articulated crowns and cups. The fauna contains representatives of each of the major Paleozoic crinoid clades: Cladida (including the Flexibilia), Disparida, and Camerata. Identified genera suggest a greater affinity with North American faunas than with Tethyan faunas. Four new species,Neoprotencrinus anyangensis,Ulocrinus qiaoi,Artichthyocrinus limani, andSynbathocrinus chenae, are proposed herein.UUID:http://zoobank.org/D08DDDCD-485C-45CC-A014-C1CB58C26588

Biostratigraphy and petrography of upper Paleozoic rocks of Sierra Las Pintas, northern Baja California

A transported crinoid fauna is herein described for the first time in the Paleozoic succession cropping out in the Sierra Las Pintas, northern Baja California, northwestern Mexico. The fossil association includes Heterostelechus texanus Moore and Jeffords, Preptopremnum laeve? Moore and Jeffords, and Mooreanteris perforatus Moore and Jeffords, which indicates a Middle Pennsylvanian-early Permian time-averaged age. The studied area corresponds with the northernmost outcrop of definitely late Paleozoic deep-water facies in northwestern Mexico and the southern United States. Petrographic analyses indicate that the studied metasandstones were primarily derived from high-grade metamorphic rocks and from a shallow-water platform environment dominated by crinoid meadows. These results allow the correlation of the studied metasedimentary rocks with the Carboniferous Rancho Nuevo Formation of the Sonora allochthon, which crops out in central Sonora. The Sonora allochthon includes an Early Ordovician-Late Pennsylvanian sedimentary succession that was deposited in the oceanic basin located south of the Laurentian craton. Therefore, upper Paleozoic metasedimentary rocks of the Sierra Las Pintas were deposited along the same continental margin of Laurentia as those rocks in the Sonora allochthon, and were mostly derived from metamorphic rocks of the continental craton and by the typical Carboniferous encrinites, which characterize the shallow-water rocks of central and northern Sonora.

Spinosity, regeneration, and targeting among Paleozoic crinoids and their predators

AbstractEvolving interactions between predators and prey constitute one of the major adaptive influences on marine animals during the Paleozoic. Crinoids and fish constitute a predator–prey system that may date back to at least the Silurian, as suggested by patterns of crinoid regeneration and spinosity in concert with changes in the predatory fauna. Here we present data on the frequency of breakage and regeneration in the spines of the Middle Devonian camerateGennaeocrinusand late Paleozoic cladids, as well as an expanded survey of the prevalence of spinosity and infestation by platyceratid gastropods on crinoid genera during the Paleozoic. Spine regeneration frequency in the measured populations is comparable to arm regeneration frequencies from MississippianRhodocrinitesand from modern deep-water crinoid populations. The prevalence of spinosity varies by taxon, time, and anatomy among Paleozoic crinoids; notably, spinosity in camerates increased from the Silurian through the Mississippian and decreased sharply during the Pennsylvanian, whereas spines were uncommon in cladids until their Late Mississippian diversification. Among camerates, tegmen spinosity is positively correlated with the presence of infesting platyceratid gastropods. These results allow us to evaluate several hypotheses for the effects of predation on morphological differences between early, middle, and late Paleozoic crinoid faunas. Our data corroborate the hypothesis that predators targeted epibionts on camerate crinoids and anal sacs on advanced cladids and suggest that the replacement of shearing predators by crushing predators after the Hangenberg extinction affected the locations of spines in Mississippian camerates.