Steven J. Hageman Ph.D.

There are 28 included publications by Steven J. Hageman Ph.D.:

TitleDateViewsBrief Description
Alternative Methods For Dealing With Nonnormality And Heteroscedasticity In Paleontological Data 1992 563 Although numerical methods are highly useful in paleontological studies, potential problems arise with application of parametric statistical methods to paleontological data. Most common statistical tests assume data are normally distributed and that ...
Approaches To Systematic And Evolutionary Studies Of Perplexing Groups: An Example Using Fenestrate Bryozoa 1991 511 Recognition of discrete taxa is an enduring problem in the biological sciences, especially for taxonomists who work with groups that display a great degree of homeomorphy at low taxonomic levels. Selection of the type and number of characters used to...
Bryozoan Colonial Growth Forms As Paleoenvironmental Indicators: Evaluation Of Methodology And Predictive Utility 1997 2655 Bryozoans have played a significant ecological role in many shallow marine benthic communities since the Ordovician and are important contributors to carbonate sediment production in many modern cool-water marine environments. Correlation between bry...
Bryozoan Growth Habits: Classification And Analysis 1998 838 Bryozoans are an important part of the benthic marine fauna in a wide variety of modern environments and are found in rock forming abundance in a number of settings throughout much of the Phanerozoic. Bryozoologists and nonspecialists have grouped ta...
Buenellus chilhoweensis n. sp. From The Murray Shale (Lower Cambrian Chilhowee Group) Of Tennessee, The Oldest Known Trilobite From The Lapetan Margin Of Laurentia 2018 68 The Ediacaran to lower Cambrian Chilhowee Group of the southern and central Appalachians records the rift-to-drift transition of the newly formed Iapetan margin of Laurentia. Body fossils are rare within the Chilhowee Group, and correlations are base...
Calendar Scale, Environmental Variation Preserved In The Skeletal Phenotype Of A Fossil Bryozoan (Rhombopora Blakei N. SP.), From The Mississippian Of Ireland 2011 537 A single large colony (20 cm) of Rhombopora blakei n. sp. from the Hook Head Formation of Ireland (Tournaisian Stage, Mississippian) permits an analysis of within-colony variation associated with environmental change at a calendar scale (days to deca...
Complexity Generated by Iteration of Hierarchical Modules in Bryozoa 2003 2479 Growth in colonial organisms by iteration of modules inherently provides for an increase in available morpho-ecospace relative to their solitary relatives. Therefore, the interpretation of the functional or evolutionary significance of complexity wit...
Cool-Water Carbonate Production from Epizoic Bryozoans on Ephemeral Substrates 2000 3242 Bryozoan skeletons are a dominant constituent of cool-water carbonate sediments in the Cenozoic of southern Australia. The primary substrate on much of the modern continental shelf is loose sediment that is reworked intermittently to 200+ m water dep...
Crossing The Ecological Divide: Paleozoic To Modern Marine Ecosystem In The Adriatic Sea 2007 55 The northern Adriatic Sea supports both typical modern marine benthic associations of animals that live within the sediment and other associations with a Paleozoic ecological aspect, rich in sedentary animals that live exposed on the sea floor. Site-...
Discrimination Of Fenestrate Bryozoan Genera In Morphospace 2010 98 Concepts for generic diagnoses and discrimination of biserial fenestrate Bryozoa (Fenestellidae) have varied historically, but have largely been based on specialized colony forms (e.g., Archimedes), the shape and budding arrangement of chambers and o...
Hierarchical (mm- to km-scale) Environmental Variation Affecting Skeletal Phenotype Of A Marine Invertebrate (Electra pilosa, Bryozoa): Implications For Fossil Species Concepts 2014 438 A comparative record of morphological change of fossil specimens through geologic time can provide insights into the rates and patterns of microevolution and speciation. However, questions concerning the extent to which environmental conditions influ...
Image Processing And Analysis With Microcomputers 1988 461 Recent advances in microcomputer technology have created many tools for image processing and analysis that are useful for paleontologic studies. Although the Journal of Paleontology is not the appropriate forum for reviews of products from the rapidl...
Implications Of Intracolonial Variation In A Paleozoic Bryozoan 1998 494 Relative differences between environmentally controlled variation and genetically controlled variation are important when investigating morphologic variation in general, especially when establishing species concepts. The colonial nature of bryozoans ...
The Last Phylum: Occupation Of Bryozoa Morpho-Ecospace (Colony Growth Habits) During The Early Phase Of The Great Ordovician Biodiversification Event 2019 513 Most major phyla, and all skeletonized phyla have their first appearance in the Cambrian. The exception is the Phylum Bryozoa, which first appear in the Early Ordovician (Tremadocian 1b). Bryozoans have an excellent fossil record, due in part to thei...
Magnetic Susceptibility As A Proxy For Coal Ash Pollution Within Riverbed Sediments In A Watershed With Complex Geology (Southeastern USA) 2017 973 A study of near surface sediments from the Dan River (southeastern USA) was conducted to assess the use of magnetic properties as proxies of coal ash after a recent spill. The watershed geology is diverse and potentially contributes magnetic minerals...
Magnetic Susceptibility Measurements To Detect Coal Fly Ash From The Kingston Tennessee Spill In Watts Bar Reservoir 2013 2510 An estimated 229,000 m3 of coal fly ash remains in the river system after dredging to clean-up the 2008 Tennessee Valley Authority (TVA) spill in Kingston, Tennessee. The ash is heterogeneous with clear, orange and black spheres and non-spherical amo...
Microevolutionary Implications Of Clinal Variation In The Paleozoic Bryozoan Streblotrypa 1994 451 Ideally, studies of microevolution, including those of patterns and rates of speciation, need to account for features of geographic and ecophenotypic morphologic variation. These factors can provide primary sources of variation for evolution to act u...
Morphology And Molecules: An Integrated Comparison Of Phenotypic And Genetic Rates Of Evolution 2016 250 The ability to successfully apply species and species concepts to real world problems such as biostratigraphy and conservation biology makes a strong argument for the existence of species (i.e., a level of organization that exists in the phenotype an...
Observed Phenotypic Variation In A Paleozoic Bryozoan 1995 432 Documentation of morphologic variation within and among fossil species (and larger clades) provides fundamental data needed for studies of evolution, paleoecology, and the systematic foundation required for most fields of paleobiology. In paleontolog...
The Oldest Hyolithids (Cambrian Series 2, Montezuman Stage) From The Iapetan Margin Of Laurentia 2020 478 The recent description of the nevadioid trilobite Buenellus chilhoweensis Webster and Hageman, 2018 established the presence of early Cambrian Montezuman Stage (Cambrian Series 2, Stage 3) faunas in the Murray Shale of Chilhowee Mountain, Tennessee. ...
Paleoenvironmental Significance of Celleporaria (Bryozoa) from Modern and Tertiary Cool-water Carbonates of Southern Australia 2003 4420 Certain members of the bryozoan genus Celleporaria form large, erect colonies of hollow branches ( 10–30 cm tall and 1–3 cm diameter). These are common and conspicuous in Pleistocene and Cenozoic neritic strata of the southern margin of Australia. Mo...
Paleozoic To Modern Marine Ecological Shift Displayed In The Northern Adriatic Sea 2006 503 One of the major changes in the history of life was the decline from abundant sedentary, suspension-feeding animals living on the seafloor during the Paleozoic to their relative scarcity afterward, while animal life within the sediment burgeoned afte...
Partitioning Phenotypic Variation: Genotypic, Environmental And Residual Components From Bryozoan Skeletal Morphology 1999 636 Using morphometric studies of colonial (clonal) organisms such as Bryozoa grown as replicates in controlled laboratory experiments, phenotypic variation (hard part morphology) can be partitioned into its genotypic and environmental (ecophenotypic) co...
Phenotypic Variation In The Bryozoan Leioclema Punctatum (Hall, 1858) From Mississippian Ephemeral Host Microcommunities 2006 483 The morphologic expression of microenvironmental variation is difficult to document in fossil ecosystems and therefore is poorly understood. However, documentation of environmental sources of variation in the phenotype is essential for meaningful stu...
Stable Isotope Profiles Of Skeletal Carbonate Validate Annually-Produced Growth Checks In The Bryozoan Melicerita chathamensis From Snares Platform, New Zealand 2018 103 The bryozoan Melicerita chathamensis Uttley and Bullivant, 1972 produces colonies that exhibit visible growth segments defined by narrow growth checks. If these growth checks are annual, then colony age, and seawater variations among seasons and year...
Testing Habitat Complexity As A Control Over Bryozoan Colonial Growth Form And Species Distribution 2011 488 The aim of this study is to test the effects of fine scale (microhabitat) environmental variation on the distribution of bryozoan species and potential variation in growth habit diversity and disparity. Data are derived from six microhabitats in repl...
Threshold Effects of Food Concentration on the Skeletal Morphology of the Bryozoan Electra Pilosa (Linnaeus, 1767) 2009 2656 Many palaeontological studies rely heavily on characteristics of the preserved phenotype, i.e. the morphology of skeletal hard parts. Although the potential for environmental influences on the phenotype is expected, rarely is the magnitude of the eff...
Worthenopora: An Unusual Cryptostome (Bryozoa) That Looks Like A Cheilostome 1991 479 Worthenopora is a Mississippian cryptostome bryozoan genus with certain characteristics that so closely resemble those of some cheilostomes (Jurassic--Recent) that previous bryozoan experts speculated whether Worthenopora should be assigned to the or...