Thomas W. Kammer

Species longevity as a function of niche breadth: Evidence from fossil crinoids

High-resolution stratigraphic and taxonomic data indicate that species longevities among Paleozoic (Mississippian) crinoids (Echinodermata) were affected by differences in niche breadth. A strong positive relationship exists between niche breadth, measured as the number of environments occupied by a species, and stratigraphic range. The robustness of this pattern is verified by a variety of rarefaction and statistical techniques confirming the long-held supposition that among animals ecological “generalists” have greater species longevities than ecological “specialists.” The results also support the hypothesis that specialist clades have higher species richness.

Aerosol suspension feeding and current velocities; distributional controls for late Osagean crinoids

Distributional patterns of late Osagean (Mississippian) crinoids from the east-central United States are examined using multivariate analysis of crinoid species diversity and species abundance data. We confirm previous hypotheses that three well-defined crinoid associations existed during the late Osagean. These associations were dominated, respectively, by 1) monobathrid camerates preserved in carbonate packstones; 2) poteriocrine inadunates in higher-energy siltstones and sandstones; and 3) disparid inadunates, cyathocrine inadunates, and flexibles in mudstones where neither monobathrids nor poteriocrines dominated. In conjunction with petrologic data on the enclosing sediments, the analyses suggest that these associations occurred along a spectrum of increasing current velocity at the seafloor. Camerates, poteriocrine inadunates, and flexibles are interpreted to display preferences for specific environmental conditions, whereas disparid and cyathocrine inadunates are inferred to be environmental generalists. The different environmental distributions of the major crinoid groups are interpreted to be a function of the mode or modes of aerosol filtration feeding used by each group. This inference is possible through functional morphologic and morphometric studies of crinoid arms, because the skeletal elements of the arms, which are commonly preserved, are directly involved in feeding.

Persistent predator–prey dynamics revealed by mass extinction

Predator–prey interactions are thought by many researchers to define both modern ecosystems and past macroevolutionary events. In modern ecosystems, experimental removal or addition of taxa is often used to determine trophic relationships and predator identity. Both characteristics are notoriously difficult to infer in the fossil record, where evidence of predation is usually limited to damage from failed attacks, individual stomach contents, one-sided escalation, or modern analogs. As a result, the role of predation in macroevolution is often dismissed in favor of competition and abiotic factors. Here we show that the end-Devonian Hangenberg event (359 Mya) was a natural experiment in which vertebrate predators were both removed and added to an otherwise stable prey fauna, revealing specific and persistent trophic interactions. Despite apparently favorable environmental conditions, crinoids diversified only after removal of their vertebrate consumers, exhibiting predatory release on a geological time scale. In contrast, later Mississippian (359–318 Mya) camerate crinoids declined precipitously in the face of increasing predation pressure from new durophagous fishes. Camerate failure is linked to the retention of obsolete defenses or “legacy adaptations” that prevented coevolutionary escalation. Our results suggest that major crinoid evolutionary phenomena, including rapid diversification, faunal turnover, and species selection, might be linked to vertebrate predation. Thus, interactions observed in small ecosystems, such as Lotka-Volterra cycles and trophic cascades, could operate at geologic time scales and higher taxonomic ranks. Both trophic knock-on effects and retention of obsolete traits might be common in the aftermath of predator extinction.

The “Age of Crinoids”: A Mississippian Biodiversity Spike Coincident with Widespread Carbonate Ramps

Abstract Crinoids reached their highest generic richness and overall abundance during the Mississippian, which thus has been dubbed the Age of Crinoids. The causes are hypothesized to be from the coincidence of two factors. First, in the wake of the Late Devonian mass-extinction event, the five major crinoid groups recovered and radiated in the Early Mississippian. The advanced cladids continued to radiate from their origin in the Early Devonian and reached a peak in the Middle Mississippian (Visean) that was not exceeded again until the Middle Pennsylvanian (Moscovian). Second, the Late Devonian mass-extinction event destroyed the extensive coral-stromatoporoid platform-edge reefs that had restricted circulation on carbonate platforms and limited the abundance of crinoids, which are stenohaline. The resulting carbonate ramps during the Mississippian had improved circulation, producing stenohaline conditions that resulted in an abundance peak for crinoids, recorded by widespread regional encrinites on multiple continents. This increased habitat space was ideal for camerate crinoids and resulted in a new radiation of camerate crinoids. The simultaneous radiation of pinnulate cladids and the short resurgence of camerates were responsible for the biodiversity spike in the Mississippian. The Age of Crinoids ended with a major drop in sea level at the end of the Mississippian as massive glaciers formed on Gondwana and epicontinental seas were drained.

Demise of the middle Paleozoic crinoid fauna: a single extinction event or rapid faunal turnover?

Macroevolutionary change from the Middle to the Late Paleozoic crinoid fauna was not the result of mass extinction. The presumption that the decline of the middle Paleozoic crinoid fauna was from a single mass extinction event was tested using seriation, multidimensional scaling (MDS), binomial analysis, and bootstrapping simulations on a data set which is a comprehensive revision of old faunal lists. The data for these analyses were based on temporal distributions of 214 species from 69 late Osagean and early Meramecian localities from the midcontinental United States. The time under consideration is subdivided into seven informal intervals using MDS in conjunction with biostratigraphy. Seriation of species ranges into these intervals results in a gradual pattern of faunal turnover, and sampling bias can be eliminated as a cause for this more gradual pattern. MDS analysis of the crinoid range data is similar to MDS simulations using data with continuous, mono- tonic species turnover and dissimilar to a simulated mass extinction. Binomial analysis and boot- strapping demonstrate that the observed number of extinctions at the putative extinction boundary were not unusually high. All methods agree that extinctions throughout this time were high but spanned several time intervals and that rapid, monotonic faunal turnover describes the data better than mass extinction. Macroevolutionary processes other than mass extinction and microevolution- ary processes must have dictated the character and composition of this remarkable faunal transition among the Crinoidea.

Advanced cladid crinoids from the middle Mississippian of the east-central United States: intermediate-grade calyces

Species of the late Osagean and early Meramecian advanced cladid crinoid genera (suborder Poteriocrinina) Abrotocrinus, Aulocrinus, Cromyocrinus. Decadocrinus, Dinotocrinus, Holcocrinus, Hylodecrinus, Lanecrinus n. gen., Pachylocrinus, Parascytalocrinus n. gen., and Stinocrinus from Illinois, Indiana, Iowa, Kentucky, and Missouri are redescribed and redefined from study of type material and museum collections. Nomenclatural and systematic acts include the following: 1) Abrotocrinus cymosus Miller and Gurley, 1890a, is a valid species and not a synonym of A. coreyi (Meek and Worthen, 1869); 2) A. coreyi is a senior synonym of Poteriocrinus orestes Worthen, 1882; 3) Scaphiocrinus manus Miller and Gurley, 1890a, is assigned to Abrotocrinus ; 4) Abrotocrinus granulatus n. sp. is described; 5) S. bellus Miller and Gurley, 1890a, is assigned to Aulocrinus and is a senior synonym of Aulocrinus agassizi Wachsmuth and Springer, 1897; 6) S. orbicularis Hall, 1861a, is assigned to Cromyocrinus ; 7) P. latidactylus Worthen, 1882, is assigned to Dinotocrinus ; 8) S. gibsoni White, 1878, is assigned to Hylodecrinus with P. nauvooensis Worthen, 1882, questionably placed in synonymy; 9) P. briareus Worthen, 1882, is assigned to Hylodecrinus and is a senior synonym of S. lacunosus Miller and Gurley, 1890a, S. boonvillensis Miller, 1891b, S. constrictus Miller, 1891a, and S. arrosus Miller and Gurley, 1893; 10) S. bonoensis Miller and Gurley, 1890a, is assigned to Hylodecrinus ; 11) Hylodecrinus robustus n. sp. is described; 12) P. validus Worthen, 1882, is questionably assigned to Hylodecrinus ; 13) Lanecrinus n. gen. is described and the following species are assigned to this new genus: S. halli Hall, 1861 a, S. depressus Meek and Worthen, 1870, P. milleri Wetherby, 1881, P. fountainensis Worthen, 1882, S. repertus Miller and Gurley, 1890a, and Ramulocrinus consectatus Strimple and Watkins, 1969; P. otterensis Worthen, 1882, is questionably assigned to Lanecrinus ; 14) Lanecrinus depressus is the senior synonym of P. ulrichi Worthen in Miller, 1889, and S. maniformis Miller, 1892; 15) Lanecrinus repertus is the senior synonym of S. gorbyi Miller, 1891a; 16) P. asper Worthen, 1882, is assigned to Pachylocrinus and is a senior synonym of S. extensus Wachsmuth and Springer, 1886; 17) Parascytalocrinus n. gen. is described and the following species are assigned to this new genus: Poteriocrinus hamiltonensis Worthen, 1882, and Scytalocrinus validus Wachsmuth and Springer, 1897; 18) Poteriocrinites mcadamsi Meek and Worthen, 1873, is questionably placed in synonymy with Parascytalocrinus hamiltonensis ; and 19) Poteriocrinus burketi Worthen, 1882, nomen dubium and Zeacrinus dubius Miller and Gurley, 1890a, are placed in Incertae Sedis. Cromyocrinus orbicularis is the oldest species of its genus extending the range of the genus downward from the Upper to the Lower Mississippian.

Oral region homologies in paleozoic crinoids and other plesiomorphic pentaradial echinoderms.

The phylogenetic relationships between major groups of plesiomorphic pentaradial echinoderms, the Paleozoic crinoids, blastozoans, and edrioasteroids, are poorly understood because of a lack of widely recognized homologies. Here, we present newly recognized oral region homologies, based on the Universal Elemental Homology model for skeletal plates, in a wide range of fossil taxa. The oral region of echinoderms is mainly composed of the axial, or ambulacral, skeleton, which apparently evolved more slowly than the extraxial skeleton that forms the majority of the body. Recent phylogenetic hypotheses have focused on characters of the extraxial skeleton, which may have evolved too rapidly to preserve obvious homologies across all these groups. The axial skeleton conserved homologous suites of characters shared between various edrioasteroids and specific blastozoans, and between other blastozoans and crinoids. Although individual plates can be inferred as homologous, no directly overlapping suites of characters are shared between edrioasteroids and crinoids. Six different systems of mouth (peristome) plate organization (Peristomial Border Systems) are defined. These include four different systems based on the arrangement of the interradially-positioned oral plates and their peristomial cover plates, where PBS A1 occurs only in plesiomorphic edrioasteroids, PBS A2 occurs in plesiomorphic edrioasteroids and blastozoans, and PBS A3 and PBS A4 occur in blastozoans and crinoids. The other two systems have radially-positioned uniserial oral frame plates in construction of the mouth frame. PBS B1 has both orals and uniserial oral frame plates and occurs in edrioasterid and possibly edrioblastoid edrioasteroids, whereas PBS B2 has exclusively uniserial oral frame plates and is found in isorophid edrioasteroids and imbricate and gogiid blastozoans. These different types of mouth frame construction offer potential synapomorphies to aid in parsimony-based phylogenetics for exploring branching order among stem groups on the echinoderm tree of life.

Primitive cladid crinoids from upper Osagean-lower Meramecian (Mississippian) rocks of east-central United States

Species of the late Osagean and early Meramecian primitive cladid crinoid genera Atelestocrinus, Barycrinus, Cestocrinus, Costalocrinus, Cyathocrinites, Meniscocrinus n. gen., Parisocrinus, Pellecrinus , and Saccosomopsis from Illinois, Indiana, Iowa, Kentucky, Missouri, and Tennessee are reviewed, redescribed, and redefined from study of type material, museum collections, and field collections. Nomenclatural and systematic acts include the following: 1) Barycrinus spurius (Hall, 1858) is a senior synonym of Cyathocrinus tumidus Hall, 1858, C. protuberans Hall, 1858, and B. mammatus Meek and Worthen, 1873; 2) B. rhombiferus (Owen and Shumard, 1852a) is a senior synonym of C. sculptilis Hall, 1860, C. thomae Hall, 1860, C. hoveyi Hall, 1861a, C. wachsmuthi Meek and Worthen, 1861, B. herculeus Meek and Worthen, 1868, B. pentagonus Meek and Worthen, 1873, B. striatus Worthen, 1875, B. boonvillensis Miller, 1891b, B. formosus Miller and Gurley, 1894, B. washingtonensis Miller and Gurley, 1895, and B. elrodi Miller and Gurley, 1896a; 3) B. magister (Hall, 1858) is a senior synonym of C. solidus Hall, 1861a and B. magnificus Meek and Worthen, 1868; 4) B. stellatus (Hall, 1858) is a senior synonym of C. bullatus Hall, 1858, C. angulatus Meek and Worthen, 1860, C. quinquelobus Meek and Worthen, 1865, and B. astericus Van Sant, 1964; 5) B. crassibrachiatus (Hall, 1860) is a senior synonym of B. princeps Miller and Gurley, 1890a; 6) B. geometricus Meek and Worthen, 1873, is considered a nomen dubium; 7) B. benedicti (Miller, 1891a) is considered a nomen dubium; 8) Cyathocrinus signatus Miller and Gurley, 1894, is assigned to Cestocrinus and is a senior synonym of Cestocrinus striatus Kirk, 1940; 9) Cyathocrinites iowensis (Owen and Shumard, 1850) is a senior synonym of C. malvaceus Hall, 1858, C. divaricatus Hall, 1858, C. rotundatus Hall, 1858, C. viminalis Hall, 1861a, C. parvibrachiatus Hall, 1861a, C. hamiltonensis Worthen, 1882, C. nodosus Wachsmuth and Springer, 1890, C. brevisacculus Wachsmuth and Springer, 1890, C. opimus Miller and Gurley, 1890a, and C. gurleyi Miller, 1891a; 10) C. kelloggi (White, 1862) is a senior synonym of C. subtumidus Meek and Worthen, 1865; 11) C. farleyi (Meek and Worthen, 1866b) is a senior synonym of C. andersoni Miller and Gurley, 1894, C. granulosus Rowley, 1902, and C. snivelyi Rowley, 1902; 12) C. harrodi (Wachsmuth and Springer, 1880) is a senior synonym of C. boonvillensis Miller, 1891b, C. gorbyi Miller, 1892b, and C. astralus Kammer, 1984; 13) Meniscocrinus n. gen. is described and M. magnitubus n. sp. is assigned to this new genus; 14) C. labyrinthicus Miller, 1891a, is assigned to Parisocrinus ; 15) C. intermedius Hall, 1858, is assigned to Pellecrinus ; and 16) C. insperatus Lyon, 1869, is assigned to Saccosomopsis and is a senior synonym of C. ? poterium Meek and Worthen, 1870.

Redefinition of the Osagean-Meramecian boundary in the Mississippian stratotype region

Analysis of fossil occurrences in late Osagean-early Meramecian stratotype beds of the upper Mississippi River Valley shows that major faunal changes occur within the Warsaw Formation, not at the underlying Keokuk-Warsaw formational contact where the Osagean-Meramecian serial boundary is presently placed. Relying on this evidence, the authors propose raising this boundary to the base of the informal upper Warsaw member described herein. The boundary is recognized by the first occurrence of the brachiopods Warsawia lateralis, Planalvus densa, Crossacanthia perlamellosa, Setigerites altonensis, and Tetracamera subcuneata, the blastoid Pentremites conoideus, and the calcareous foraminifer Globoendothyra baileyi. Use of these fossil appearances provides a more rigorous definition of the serial boundary and permits correlation beyond the Mississippi River Valley. Foraminifers suggest that the boundary falls within the middle Visean of western Europe. The stratotype section for the proposed boundary is located near the type locality of the Meramecian Series at Meramec Highlands, St. Louis County, Missouri. The lithostratigraphy of the late Osagean and early Meramecian is reviewed in key areas within the Mississippi River Valley and a new member, the Peerless Park, is proposed for a shoaling unit within the middle of the Keokuk Limestone.

Genetic stratigraphy and depositional systems of the upper Devonian-lower Mississippian Price-Rockwell deltaic complex in the central Appalachians, U.S.A.

Abstract Rocks of the Price and Rockwell formations comprise the uppermost Devonian-Lower Mississippian deltaic complex in the central Appalachians. The Price Formation is dominantly marine and refers to all uppermost Devonian-Lower Mississippian rocks above either Hampshire Group red beds or the marine Greenland Gap Formation and below either the Greenbrier Limestone Group or Maccrady Formation red beds in the central Appalachians. The Rockwell Formation is dominantly non-marine and refers to equivalent rocks in south-central Pennsylvania and the Maryland-West Virginia panhandle region. Members of the Price Formation are generally equivalent to discrete genetic events. Price deposition was initiated in latest Devonian time when a regional transgression covered delta and alluvial plain facies of the Catskill deltaic complex with protected-bay and strandline facies of the Oswayo Member in West Virginia, Pennsylvania and western Maryland. Farther south, these transgressive facies overlie the Cloyd Conglomerate Member, a thin regressive-transgressive sedimentary wedge, and occur in the lower part of the Sunbury Shale Member. Subsurface Berea Sandstone deposition corresponded to regional exposure and erosion in the outcrop belt. This unconformable surface was overstepped in earliest Mississippian time by a major transgression that deposited a variably thick but persistent basal transgressive sandstone during shoreface retreat. Sandstones that have been referred to the “Cussewago Sandstone” in northern West Virginia and southwest Pennsylvania are part of this basal sandstone. Eastward, these sandstones thicken, coarsen and interbed with a polymictic diamictite at the base of the Rockwell Formation. Shaly facies of the earliest Mississippian transgression overlie the basal sandstone. The Riddlesburg Shale preserves offshore and open-bay facies in West Virginia that grade eastward to estuarine and restricted, back-bar lagoon and marsh facies of a barred-bay complex in south-central Pennsylvania and the Maryland-West Virginia panhandle. From central West Virginia, Riddlesburg facies grade southward into basinal facies of the Sunbury Shale Member. Syndepositionally active basement features, the West Virginia Dome and “Tri-State Block”, were structurally positive areas in the foreland basin. The “Tri-State Block” caused truncation of Lower Mississippian marine facies in western Maryland and large-scale westward erosional overlap of channel-fill sandstones in the upper Rockwell Formation. The West Virginia Dome was also structurally positive and the basal transgressive sandstone contains phosphatic omission surfaces on the dome crest. Lack of subsidence caused scour and incision of Riddlesburg facies by overlying deltaic facies. Progradation ensued with fluvial-dominant, shallow-water deltaic systems (Price Rockwell Member) in northern West Virginia and marine-dominant deep-water deltaic facies farther south. A 150 m minimum paleodepth estimate in the foreland basin is based on stratigraphic thickness in southern West Virginia. Following a transgression near the Kinderhookian-Osagean boundary. Price marine-deltaic facies form a coarsening-upward sequence to delta plain coals and coastal-alluvial plain red beds. A 35 m estimate for average storm wave base utilized tempestite proximal-distal trends.