An unusual occurrence of a colony of microcrinoids from shale within a fragment of a large orthoconic nautiloid body chamber is described from the Imo Formation (Mississippian, Chesterian) near Elba, Arkansas. The colony, about 70... more
An unusual occurrence of a colony of microcrinoids from shale within a fragment of a large orthoconic nautiloid body chamber is described from the Imo Formation (Mississippian, Chesterian) near Elba, Arkansas. The colony, about 70 individuals, consists principally of immature specimens that lack facets for the arms, and a few mature specimens with four or five arm facets. The crinoids are interpreted as record of a census population that was engulfed suddenly by mud. The crinoids are assigned to Allagecrinus coronarius Gutschick, 1968. The body chamber may have been broken during predation by other large cephalopods, or sharks, known from the Imo, or by post-mortem transport. The shell served as a firm substrate on which the microcrinoid larvae could settle and the convex sides may have provided some protection from currents.
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Coleoidea (squids and octopuses) comprise all crown group cephalopods except the Nautilida. Coleoids are characterized by internal shell (endocochleate), ink sac and arm hooks, while nautilids lack an ink sac, arm hooks, suckers, and have... more
Coleoidea (squids and octopuses) comprise all crown group cephalopods except the Nautilida. Coleoids are characterized by internal shell (endocochleate), ink sac and arm hooks, while nautilids lack an ink sac, arm hooks, suckers, and have an external conch (ectocochleate). Differentiating between straight conical conchs (orthocones) of Palaeozoic Coleoidea and other ectocochleates is only possible when rostrum (shell covering the chambered phragmocone) and body chamber are preserved. Here, we provide information on how this internalization might have evolved. We re-examined one of the oldest coleoids, Gordoniconus beargulchensis from the Early Carboniferous of the Bear Gulch Fossil-Lagerstätte (Montana) by synchrotron, various lights and Reflectance Transformation Imaging (RTI). This revealed previously unappreciated anatomical details, on which we base evolutionary scenarios of how the internalization and other evolutionary steps in early coleoid evolution proceeded. We suggest tha...
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Research Interests: Evolutionary Biology, Geology, Paleontology, Biology, Ecology, and 4 moreCladistics, Carboniferous, Genus, and Taxon
Research Interests: Evolutionary Biology, Geology, Paleontology, Ecology, Carboniferous, and 3 moreFauna, Genus, and Juvenile
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FIG. 8. — Surface rendering generated from CT Scan slices of AMNH FF 20852: A, postero-lateral view of the braincase (blue); the transverse microtomographic slices of B and C are indicated in red line. The red colored area of the... more
FIG. 8. — Surface rendering generated from CT Scan slices of AMNH FF 20852: A, postero-lateral view of the braincase (blue); the transverse microtomographic slices of B and C are indicated in red line. The red colored area of the braincase in B and C represent the intramural diverticuli of the posterior fossa bridgei. Abbreviations: see Material and methods. Scale bars: 5 mm.
FIG. 3. — Surface rendering generated from CT Scan slices of the dorsal surface of the braincase (blue) of AMNH FF 20852. Grey area, not perichondrally lined surface. Abbreviations: see Material and methods. Scale bar: 5 mm.
FIG. 7. — Surface rendering generated from CT Scan slices of AMNH FF 20852 in posterior view: A, braincase (blue); B, braincase and associated bones (intercalar in pink; parasphenoid in red). Grey area, not perichondrally lined surface.... more
FIG. 7. — Surface rendering generated from CT Scan slices of AMNH FF 20852 in posterior view: A, braincase (blue); B, braincase and associated bones (intercalar in pink; parasphenoid in red). Grey area, not perichondrally lined surface. Abbreviations: see Material and methods. Scale bar: 5 mm.
FIG. 9. — Microtomographic slices through the intercalars of AMNH FF 20852: A, cross section; B, saggital section through the left intercalar. Abbreviations: see Material and methods. Scale bar: 5 mm.
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Recovery of hyoliths from the Eudora Shale in southeastern Kansas and the Wolf Mountain Shale in north-central Texas constitutes the first occurrences of this group from the Pennsylvanian of North America. All specimens are preserved as... more
Recovery of hyoliths from the Eudora Shale in southeastern Kansas and the Wolf Mountain Shale in north-central Texas constitutes the first occurrences of this group from the Pennsylvanian of North America. All specimens are preserved as pyritized internal molds. Many are sufficiently well preserved to be distinguishable from Hyolithes on the basis of transverse section and internal ornamentation; these are referred to Lirotheca wilsoni n. gen., n. sp. All other specimens lacking ornament and other distinctive features are assigned to Hyolithes? sp. The Kansas hyoliths occur with an abundant and diverse fauna including juvenile ammonoids and other molluscs, many of which are less than 3 mm in length. This suggests that these molluscs including the hyoliths are juvenile. The Texas hyoliths occur with a normal-size marine fauna, but their degree of maturity cannot be determined readily because they are too fragmentary.--Journal abstract.
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Reinterpretation of the North American Strobilepis spinigera Clarke 1888 from the Devonian and the find of Diadeloplax paragrapsima gen. et sp. n. from the Pennsylvanian provide the basis for the recognition of a new class of uncertain... more
Reinterpretation of the North American Strobilepis spinigera Clarke 1888 from the Devonian and the find of Diadeloplax paragrapsima gen. et sp. n. from the Pennsylvanian provide the basis for the recognition of a new class of uncertain affinity, Multiplacophora. The range of the class is Middle Devonian (Erian) to Pennsylvanian (Morrowan). Multiplacophora differ from the order Hercolepadida and the classes Tharnbetolepida and Polyplacophora in the number, shape, and arrangement of plates; the presence of large spines; and the complexity of internal canal systems in the plates and spines.
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Three new species of Hippocardia, H. ancora, H. pala, and H. cucullata, are described. Hippocardia ancora and H. pala occur together in the Lazy Bend Formation (Desmoinesian) of Texas. Hippocardia cucullata occurs in the Imo Formation... more
Three new species of Hippocardia, H. ancora, H. pala, and H. cucullata, are described. Hippocardia ancora and H. pala occur together in the Lazy Bend Formation (Desmoinesian) of Texas. Hippocardia cucullata occurs in the Imo Formation (Chesterian) of Arkansas.
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Damage displayed by 18 of 954 relatively mature (> 35 mm diameter) specimens ofGonioloboceras goniolobum(Meek) from North American Midcontinent Upper Carboniferous sediments is interpreted to be bite marks caused by condrichthyans and... more
Damage displayed by 18 of 954 relatively mature (> 35 mm diameter) specimens ofGonioloboceras goniolobum(Meek) from North American Midcontinent Upper Carboniferous sediments is interpreted to be bite marks caused by condrichthyans and other fish, particularly the symmoriid sharkSymmorium reniforme.It is likely that these and other predators regularly preyed onGonioloboceras goniolobumbecause all of the analyzed specimens ofGoniolobocerasexhibit some evidence of unrepaired damage, including broached camerae and missing body chambers. Two new characteristics utilized with caution to detect predatory events on ammonoids are raised oval or circular pedestals on internal molds and the breakage and termination of septa in conjunction with a broken external shell. When sufficient damage to theGoniolobocerasconchs occurred during predatory attacks, the broached camerae flooded, the conch became negatively buoyant, and it sank in the vicinity of the attack. When preserved, these conchs fo...
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Research Interests: Geology and Carboniferous
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Four species of Emilites are now known; these are E. incertus (Böse), E. plummeri Ruzhencev, E. brownwoodi n. sp., and E. bennisoni n. sp. Representatives of this genus may occur as early as Middle Pennsylvanian in North America to as... more
Four species of Emilites are now known; these are E. incertus (Böse), E. plummeri Ruzhencev, E. brownwoodi n. sp., and E. bennisoni n. sp. Representatives of this genus may occur as early as Middle Pennsylvanian in North America to as late as Early Permian in the Soviet Union. All described taxa are from North America except E. plummeri, which is from the Soviet Union. Because Emilites is extremely rare in upper Paleozoic ammonoid assemblages, generic and species level phylogenetic relationships are poorly understood. Emilites is not considered to be a good generic-level zone indicator due to its relatively long time range and its rarity.
Research Interests: Evolutionary Biology, Geology, Paleontology, Ecology, Permian, and 4 morePaleozoic, Genus, Pennsylvanian, and Taxon
Upper Pennsylvanian dysoxic marine shales of midcontinent North America yield permineralized remains of apparently extrabasinal vegetation. A large percentage of the plants are surprisingly unlike the well known swamp, fluvial and... more
Upper Pennsylvanian dysoxic marine shales of midcontinent North America yield permineralized remains of apparently extrabasinal vegetation. A large percentage of the plants are surprisingly unlike the well known swamp, fluvial and lacustrian floras of the late Paleozoic paleotropics, revealing numerous aspects of the morphology, anatomy and reproductive biology of plants that may have been ancestral to the dominant taxa of the Mesozoic. Included among the assemblages are ovulate coniferophyte remains that demonstrate the occurrence of vojnovskyalean seed plants in equatorial Euramerica. Specimens consist of simple ovulate cones that are more-or-less clustered along eustelic stems in the axils of helically arranged, strap-shaped leaf bases, and are described as Sergeia neuburgii new genus and species. Individual cones are up to approximately 2 cm long and 1.5 cm in maximum diameter, with helically arranged scales and sporophylls that diverge from a eustelic axis. Scales occur in the ...
Research Interests: Evolutionary Biology, Geology, Paleontology, Biology, Ecology, and 4 morePaleozoic, Pennsylvanian, Sporangium, and ovule
The varying body chamber lengths and the different attachment of muscles and mantle to conch wall belong to the major adaptations to their diverse modes of locomotion. Therefore, these traits are indirect indicators of different life... more
The varying body chamber lengths and the different attachment of muscles and mantle to conch wall belong to the major adaptations to their diverse modes of locomotion. Therefore, these traits are indirect indicators of different life styles. The sparse record of ammonoid body chamber lengths and attachment marks has impeded the understanding of this aspect of ammonoid paleobiology. The examination of body chamber length revealed that the decrease of the ammonitella body chamber lengths shows is the long-term trend characterizing the evolutionary development of the Goniatitida–Prolecanitida–Ceratitida–Phylloceratida branch of the Ammonoidea. The analysis of the body chamber lengths and the attachment marks leads to conclusion that a precondition for the jet-powered swimming of ammonoids is less than one whorl body chamber length and the position of the attachment marks in sites from where the cephalic retractor and funnel retractor muscles would be able to extend straight across to the head and to the funnel. This is the case of goniatitids and ammonitids possessing moved forward large ventrolateral muscle marks; jet-powered swimming is highly probable for them. None of the universal small dorsal, umbilical and ventral marks may be left in the attachment sites of the cephalic retractor and funnel retractor muscles. In the hook-shaped terminal body chambers of heteromorph ammonoids, like Audouliceras, the long tongue-like umbilical marks perhaps indicate the moved forward strong umbilical muscles adapted for regular change of the mantle cavity volume for sucking and filtering seawater. This suggests that such ammonoids fed on fine plankton or suspended organic rich substance. Their irregular coiled spiral shells, best suited to floating and perhaps vertical (diurnal) migrations, support the view above. The fossilized mantle so far described in the ceratitid ammonoid Austrotrachyceras has a laminated structure fibrous seen in internally shelled Jurassic belemnotheutis and Loligosaepia.
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ABSTRACT Download: http://palaios.sepmonline.org/content/30/7/503.full.pdf+html If you cannot download please request the full text... The extant Nautilus nowadays exclusively lives in the Indo-Pacific Ocean along the slopes of coral... more
ABSTRACT Download: http://palaios.sepmonline.org/content/30/7/503.full.pdf+html If you cannot download please request the full text... The extant Nautilus nowadays exclusively lives in the Indo-Pacific Ocean along the slopes of coral reefs, mainly in water depths of 300–400 m. It possesses a complex gas-liquid combined system to regulate its buoyancy in the water column. After death this system is lost and the shells become either positively or negatively buoyant and float for some time or respectively sink to the seafloor where taphonomic processes strongly influence the shell’s condition. A major process in taphonomy is bioerosion. We present herein a detailed study of the influence of taphonomic pathways on bioerosion in backshore collected and deep-water dredged Nautilus shells from the New Caledonia region. Some bioerosion of Nautilus shells may take place during life but most occurs after death and deposition of the shell. The ichnocoenosis found in the shells collected in backshore settings indicates that these shells were positively buoyant after the death of the animals and were initially deposited in a nearshore environment (shallow euphotic zone III to deep euphotic zone) before they were transported ashore. Part of the deep-water dredged shells, in contrast, were initially deposited in the deep euphotic to dysphotic zone before being transported into aphotic depths. We demonstrate that bioerosion supports the reconstruction of taphonomic pathways of Nautilus shells and, because bioerosion is based on an actualistic approach, it can help to reconstruct taphonomic processes and depositional settings for fossil cephalopod shells.
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Color patterns on ammonoid cephalopods are rarely preserved despite the fact that millions of the shells of these extinct animals have been recovered from Devonian through the Upper Cretaceous rocks that were deposited in a wide variety... more
Color patterns on ammonoid cephalopods are rarely preserved despite the fact that millions of the shells of these extinct animals have been recovered from Devonian through the Upper Cretaceous rocks that were deposited in a wide variety of marine environments around the world. New information on this biological feature continues to be slowly discovered; however, rarity continues to limit the study of this phenomenon. New discoveries of the past twenty years include several cases of false color patterns and the documentation of iridescent color patterns that appear to have become extinct at the end of the Cretaceous with the demise of the ammonites. Additionally, there appears to be a direct relationship to different color patterns (longitudinal bands, transverse bands, monochromatic shells and no preserved color pattern) in the Lower Triassic to habitat and life mode. It is unknown if this relationship holds true for post Triassic occurrences.
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A new species of permineralized Pityostrobus cone, Pityostrobus milleri Falder et al., sp. nov. has been discovered in a calcareous nodule from shallow marine sediments of Early Cretaceous (latest Aptian; Clansenian) age in the Caucasus... more
A new species of permineralized Pityostrobus cone, Pityostrobus milleri Falder et al., sp. nov. has been discovered in a calcareous nodule from shallow marine sediments of Early Cretaceous (latest Aptian; Clansenian) age in the Caucasus Mountains in southwestern ...
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... 3 Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403, USA (e-mail: mmyacob@bgnet.bgsu.edu ). ... The specimens used in this study are from a road cut on US Highway 65, approximately 400 m southwest of... more
... 3 Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403, USA (e-mail: mmyacob@bgnet.bgsu.edu ). ... The specimens used in this study are from a road cut on US Highway 65, approximately 400 m southwest of Peyton Creek Bridge, Van Buren ...
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Small gastropod opercula have been found at one locality each in the Desmoinesian and Virgilian of north-central Texas. Because of their general shape and concentric growth, these opercula are placed within the Neritacea. One form... more
Small gastropod opercula have been found at one locality each in the Desmoinesian and Virgilian of north-central Texas. Because of their general shape and concentric growth, these opercula are placed within the Neritacea. One form probably is the operculum ofTrachydomia. Four other forms, two of which are morphologically quite similar but from different ages, probably belong withNaticopsissensu lato.
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Thirty localities in the Upper Paleozoic (Mississippian–Permian) of North America have yielded more than 1,000 cephalopod mandibles preserved as carbon films, pyrite/limonite internal molds, and as nuclei in phosphate, carbonate, and... more
Thirty localities in the Upper Paleozoic (Mississippian–Permian) of North America have yielded more than 1,000 cephalopod mandibles preserved as carbon films, pyrite/limonite internal molds, and as nuclei in phosphate, carbonate, and ironstone concretions. With occasional exceptions, cephalopod mandibles, as part of either the microfauna or macrofauna, are rare despite the fact that co-occurring cephalopods may be extremely abundant. Without exception, the mandibles recovered co-occur with ammonoids and very frequently with bactritoids. Localities containing only nautiloids, either coiled or orthoconic, have not yet yielded cephalopod mandibles. Also, nekroplanktic accumulations of cephalopods have not yielded mandibles. Except for Lagerstätten deposits (two occurrences), the cephalopod mandibles were always recovered from molluscan-dominated communities; these communities have been interpreted as being in relatively offshore, “deeper” water in normal marine salinities with relative...
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Abstract Early Emsian claystones and marls of the Tafilalt yielded two diverse and prolific faunas with nearly 5000 specimens belonging to at least 100 species being recovered and identified. The older of the two faunas contains what may... more
Abstract Early Emsian claystones and marls of the Tafilalt yielded two diverse and prolific faunas with nearly 5000 specimens belonging to at least 100 species being recovered and identified. The older of the two faunas contains what may be the oldest bactritids, pyrgocystid edrioasteroids, phyllocarid carapaces, complete asteropygid trilobites, acanthodian fin spines rarely preserved as pairs, and articulated machaeridians. Additionally, the lower interval yielded a diverse and largely infaunal bivalve assemblage. The younger fauna is ...
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For over 30 years, Ted White has scoured the quarries and road cuts of the lower Platte River Valley in southeastern Nebraska for late Pennsylvanian invertebrate and vertebrate fossils. His years of collecting have provided information... more
For over 30 years, Ted White has scoured the quarries and road cuts of the lower Platte River Valley in southeastern Nebraska for late Pennsylvanian invertebrate and vertebrate fossils. His years of collecting have provided information that significantly amplifies the history of the late Pennsylvanian in the entire North American Midcontinent. Some highlights of Ted's influence in paleontology show that he is an excellent and well-deserving recipient of the Harrell L. Strimple Award for 1986. Ted's work has not only led several young people into paleontological careers but has altered the course of research of many established professionals.
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Larval forms of the middle and late Pennsylvanian trilobite Ditomopyge scitula (Meek and Worthen, 1865) have been collected from seven localities in the Desmoinesian of Oklahoma, Missourian of Oklahoma and Texas, and Virgilian of Nebraska... more
Larval forms of the middle and late Pennsylvanian trilobite Ditomopyge scitula (Meek and Worthen, 1865) have been collected from seven localities in the Desmoinesian of Oklahoma, Missourian of Oklahoma and Texas, and Virgilian of Nebraska and Texas. These larval trilobites have been interpreted as degree 1 through degree 8 meraspides. Although these larval forms are extremely rare, an essentially complete growth sequence was reconstructed and an ontogeny synthesized. During growth, D. scitula absorbed the brim and posterior spines into the pygidium and developed first the lateral then the median preoccipital glabellar lobes; the anterior cephalic margin is more prominent in juvenile stages, becoming narrower in late mersapide molts and finally overlapped by the glabella in early holaspide stages.
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Ultrastructural study of a longiconic cephalopod, formerly described as Bactrites postremus (Miller, 1930; Mapes, 1979), reveals that the shell wall, consisting of two prismatic layers and lacking a nacreous layer, differs strongly from... more
Ultrastructural study of a longiconic cephalopod, formerly described as Bactrites postremus (Miller, 1930; Mapes, 1979), reveals that the shell wall, consisting of two prismatic layers and lacking a nacreous layer, differs strongly from that of bactritoids. In the bactritoids, the shell wall after hatching is composed of the principal nacreous and thin outer prismatic layers, and only the embryonic shell, or bactritella, has a prismatic ultrastructure (Doguzhaeva, 1996a-c). Phragmocones possessing a marginal siphuncle and a prismatic shell wall are known in Recent Spirula and Cretaceous members of Spirulida: Groenlandibelus, Naefia and Adygeya (Doguzhaeva, 1996d). Ultrastructural comparison of the shell wall in so-called B. postremus and the four spirulid genera listed above supports the conclusion that the two distinctly separated prismatic layers of the shell wall represent the outer and inner plates sensu Appellof (1893), which were secreted as an internal shell. Thus, the form described as B. postremus cannot be assigned to Bactritoidea. It is redescribed as Shimanskya gen. nov. postremus (Miller, 1930), and is considered to be the earliest known member of the order Spirulida. On the basis of this form the family Shimanskyidae fam. nov. is established.
Research Interests: Geology and Carboniferous
... reported in the follow-ing Carboniferous goniatites: Glaphyrites (Closs and Gordon, 1966), Cravenoceras (Tanabe and Mapes, 1995) and ... chemical substitution during fossilization (phosphatized in soft-bodied squids from the Jurassic... more
... reported in the follow-ing Carboniferous goniatites: Glaphyrites (Closs and Gordon, 1966), Cravenoceras (Tanabe and Mapes, 1995) and ... chemical substitution during fossilization (phosphatized in soft-bodied squids from the Jurassic Oxford Clay, England (Allison, 1988), and ...
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Page 1. Geological Society of America Special Papers doi: 10.1130/0-8137-2306-X. 351 1996;306;351-358 Geological Society of America Special Papers David L. Kidder, Rashid AM Hussein, Royal H. Mapes and Carol A. Eddy-Dilek ...
Research Interests: Geology and Geological
ABSTRACT The basic structure of the ammonitella or embryonic shell of the Ammonoidea has been well documented (Sandberger, 1851; Branco, 1879–1880, 1880–1881; Schindewolf, 1933; Erben, 1960). The ammonitella begins with a small egg-shaped... more
ABSTRACT The basic structure of the ammonitella or embryonic shell of the Ammonoidea has been well documented (Sandberger, 1851; Branco, 1879–1880, 1880–1881; Schindewolf, 1933; Erben, 1960). The ammonitella begins with a small egg-shaped or spherical initial chamber (=protoconch) (for discussion of terms see Schindewolf, 1933; House, 1996; and Landman et al., 1996; see Landman et al., 1996 for additional references) and extends as a straight shaft or coiled tube (called the ammonitella coil by House, 1996: 168). In most species the ammonitella extends approximately one whorl ending in a primary constriction (Landman et al., 1996; Klofak et al., 1999). Internally, the siphuncle originates in the initial chamber as a rounded caecum and is attached to the shell wall by a prosiphon (Landman, 1988: Figs. 1, 2 and Klofak et al., 1999: Figs. 1, 2).
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Research Interests: Paleontology, Biology, Systematics, Cladistics, Devonian, and 3 moreAmmonoidea, Carboniferous, and Paleozoic
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ABSTRACT