Showing papers in "Journal of Paleontology in 1968"

Microflora of the Bitter Springs Formation, late Precambrian, central Australia

Abstract: Thirty new species, representing 24 new genera, of green algae, blue-green algae, colonial bacteria, fungus-like filaments, and possible pyrrophytes, are described from the bedded carbonaceous cherts of the late Precambrian Bitter Springs formation, Ross river area, central Australia. Chemical data and petrologic evidence indicate that the organisms are geochemically altered but are morphologically intact. The age of the microflora is considered to be approximately 1000 m.y.

Burrowing in recent lime sediments of Florida and the Bahamas

Abstract: Supratidal, intertidal, and subtidal crustacean burrowers produce extensive 3-ft deep open networks in muddy marine sediments which can remain open beneath overburdens exceeding 8 feet. Burrows commonly become infilled, but compaction of either filled or open burrows has not been observed. Resemblances of Recent burrow networks to ancient reef-associated Stromatactis and 9reef-tuba9 structures suggest burrows as the origin for these debated structures. 9Nested-cone9 structures in cross-bedded oolite of Pleistocene age were probably produced by an anemone like the Recent form Phyllactis. Such structures can be used to differentiate between marine- and eolian deposited sands. Grain-size analysis of extensively burrowed sediments may give little information regarding energy level of the depositional environment. Polyester plastic casts of burrow networks have aided greatly in this study.

Biological and environmental rhythms reflected in molluscan shell growth

Abstract: Tidal cycles are reflected in daily growth-increment sequences in shells of many Recent and fossil mollusks. Living specimens of the bivalve Mercenaria mercenaria were notched at the growing edge of the shell and planted intertidally in Barnstable Harbor, Massachusetts. Shells from two lots, killed at intervals of 368 and 723 days after planting, show the same number of small growth increments as there were days from notching to killing. Superimposed on daily growth record are effects of winter (thin daily increments) and tides (14-day cycles of thick and thin daily increments). Comparison of Barnstable tide record with the first year's growth shows that, for each 14-day cycle, thin daily increments form during neap tides and thicker daily increments form during spring tides. Although tidal patterns are present in subtidal Mercenaria shells, they are rarely as pronounced as in intertidal ones. Spawning patterns differ from winter patterns; they are expressed in the shell by an interruption of regular deposition followed by a series of thin daily increments. Continuous sequences of bidaily patterns, one thick daily increment followed by a relatively thin one, are common in M. mercenaria. The clearest 14-day cycles of deposition were seen in shells of the bivalve Tridacna squamosa. Each daily neap-tide increment is a simple layer consisting of a dark and light zone. Each daily spring-tide increment is a complex layer consisting of two light-dark alternations separated by a depositional break that is more pronounced than the breaks delimiting daily intervals. Preliminary results of growth-increment counts in fossils show a generally decreasing trend of the mean values of days per lunar month toward the Recent. The Pennsylvanian value is 30.07 ± 0.08, a figure that is in general agreement with those of Scrutton (1964), who counted 30.59 days per month on Devonian corals, and Barker (1966), who reported more than 30 days per month in Pennsylvanian bivalves.

Post-Paleozoic adaptive radiation of infaunal bivalve molluscs; a consequence of mantle fusion and siphon formation

Abstract: The Bivalvia have undergone two principal adaptive radiations since their ap- pearance in the Ordovician. The initial, Early Paleozoic radiation gave rise to epifaunal and primitive infaunal groups and was followed by a period of relative evolutionary stability in the Late Paleozoic. A second, more spectacular radiation took place during the Mesozoic and Cenozoic Eras and brought the bivalves into their present position of prominence. The well-established idea that the many new epifaunal bivalve taxa of the Mesozoic evolved to replace extinct Paleo- zoic brachiopod groups has merit, but fails to explain the rise of the 15 new infaunal bivalve superfamilies of the post-Paleozoic radiation. All new infaunal superfamilies were siphon- feeding groups, whereas siphon feeding had been virtually absent in the Paleozoic Era. Most new siphonate taxa were eulamellibranch heterodonts or their derivatives and possessed crossed-lamellar shell structure. They probably descended from a non-siphonate Paleozoic group with similar features, such as the Astartacea. Their post-Paleozoic radiation was a consequence of mantle fusion and siphon formation, which opened the way for the occupa- tion of many new infaunal ways of life that had been inaccessible to Paleozoic bivalve and brachiopod groups. radiation of infaunal bivalves in terms of life habits has revealed that the preponderance of new Mesozoic and Cenozoic groups were bur- rowers and borers that fed by means of siphons, whereas siphon feeders had been virtually ab- sent in the Paleozoic Era. Similarity of hinge dentition, gill type, and shell structure among siphon-feeding groups suggest that most shared a common ancestry, and life habit data suggest that their adaptive radiation was a consequence of mantle fusion and the evolutionary develop- ment of siphons, which enabled them to invade many new ecologic niches. Before considering the evidence for the role of mantle fusion in bivalve diversification, three in- troductory subjects will be given brief considera- tion: the criteria to be used in measuring bivalve diversity, the general evolutionary history of the Bivalvia, and the classification of bivalves according to feeding type. MEASUREMENT OF TAXONOMIC DIVERSITY

Tremadocian trilobites from the Nochixtlan region, Oaxaca, Mexico

Abstract: Five new genera, 22 new species, new olenid subfamily (Plicatolininae), lower Tinu formation, upper Cambrian-lower Ordovician, southern Mexico

Triassic conodonts from western North America and Europe and their correlation

Abstract: Seven conodont faunal assemblages are recognized in upper Scythic, Anisic, Ladinic, and lower Carnic strata in western North America; six faunal assemblages are recognized from strata of approximately the same interval in Europe. The faunas consist of 17 genera (7 new) and 62 species (17 new). Although apparently limited in their value for intercontinental correlation, these assemblages may be useful for intraregional stratigraphic work. Three new conodont assemblage zones are recognized in the upper Carnic and Noric of both Europe and North America, which seem to have worldwide validity: Paragondolella polygnathiformis Assemblage Zone (upper Carnic), Epigondollella abneptis Assemblage Zone (lower Noric), and E. bidentata Assemblage Zone (upper Noric).

Classification and phylogeny of Cenozoic Trissocyclidae (Radiolaria) in the Pacific and Caribbean basins, Part 1

Abstract: Trissocyclid Radiolaria from 54 samples of Eocene to Quaternary age, including deep sea cores from the Pacific and outcrops in the Antilles, are described and illustrated. The family Trissocyclidae is raised from subfamily rank and emended to include members of the suborder Nassellarina that have sagittal rings. Skeletal morphology is described. Seven evolutionary lineages are arranged in five emended genera. The genera Dendrospyris and Liriospyris are emended and 9 (5 new) and 10 (6 new) species, respectively, described herein.

An application of cluster analysis as a method of determining biofacies

Abstract: Data on 44 species of Recent Foraminifera in 99 samples collected from three traverses off the central Texas coast are re-examined using the Jaccard Coefficient for data comparison and the weighted pair group method with simple arithmetic averages for cluster- ing of coefficients. The purpose of this study is to evaluate the utility of the method and to compare the results obtained with other appraisals of the same data. The technique considers only presence or absence and is simple to understand. The analyses show good agreement of station (sample to sample) distribution compared with the results of previous investiga- tions, and interspecies relationships are meaningful. The method, although not statistical, is a useful, rapid, and inexpensive empirical tool for analysis of data.

Theoretical morphology of echinoid growth

Abstract: Deutler's classic work (1926) provides the basis for an analysis of plate growth in echinoids. Deutler showed that the concentric growth rings found within each plate may be used to reconstruct the ontogeny of the entire plate pattern. New observations of growth-line configurations, particularly in Strongylocentrotus pallidus (Sars), have been used to derive a general model for echinoid growth. The plate mosaic is assumed to be the result of close packing of the growing plates. The shape of a given plate thus depends on its size and position relative to surrounding plates. The rate of meridional growth of a plate can be shown to change regularly with increasing distance from the echinoid's apical system. Migration of plates away from the apical system thus causes change in the rate of plate growth. The rate of plate migration is strongly influenced, in turn, by the rate of supply of new plates at the apical system. A mathematical model has been developed from these considerations which, when treated by digital computer (with x-y plotter output), produces ideal plate patterns (including growth rings). The constants in the model may be varied to produce a broad spectrum of echinoid plate patterns.

Quaternary calcareous dinoflagellates (Calciodinellidae) and their natural affinities

Abstract: Calciodinellum operosum Deflandre 1947, type genus of the family Calciodinellidae, and eight new morphotypes of calcareous dinoflagellates have been discovered in Quaternary marine sediments from the North Atlantic and Western Indian oceans, Mediterranean and Caribbean seas. Six of these have been isolated alive and studied in incubation experiments; so far two types have been germinated to produce motile thecate dinoflagellates identified as Peridinium trochoideum and Scrippsiella sweenyae; four others have produced athecate hypnoid protoplasts of a type commonly seen in cultures of those species among others. We conclude that Quaternary calciodinellids are peridinioid resting cysts having apical archeopyles and are produced by a small monophyletic group of dinoflagellates with the unique capability of primary calcification. Mesozoic and Tertiary calciodinellids probably are homologous with these Quaternary types.

Estimating the needed sampling area for subaquatic ecologic studies; correction

Abstract: Most traditional methods of subaquatic ecologic sampling do not collect large enough areas to provide quantitatively reliable census data. Binomial sampling theory can be used to calculate the size of randomly selected area from a benthonic community which should be examined in detail to assure that a species occupying p proportion of the benthonic surface will he missed by random sampling no more than Y proportion of the time. A graph facilitates these determinations. The graph can also be applied to the probability of a species being absent by chance from a collec- tion of individual organisms. N THE course of studying the relation of benthonic communities to bottom sediments, a critical review of bottom sampling techniques revealed that most of the procedures currently in use produce at best semi-quantitative data. Binomial sampling theory can be used as a mathematical model to determine the area of benthonic surface from which the total fauna needs to be collected to yield quantitative data with controlled reliability.

The Permian labyrinthodont amphibian Dissorophus multicinctus, and adaptations and phylogeny of the family Dissorophidae

Abstract: Dissorophus multicinctus Cope is a labyrinthodont from north-central Texas. The armor (dermal ossifications above vertebral column), sacral region, cervical region, skull, general morphology and preservation all suggest that the animal was relatively terrestrial for a Permian amphibian. A hypothesis based on degree of ossification, kinds of coexisting species, and manner of preservation, that allows the degree of terrestrial adaptation of Permian tetrapods to be compared, suggests that the Dissorophidae evolved ever increasing terrestrial adaptation and that the armor evolved, at least twice within the family, as one response to demands of the new environment. The most important function of the armor was to strengthen the vertebral column.

Structural adaptation in two Permian brachiopod genera, Salt Range, West Pakistan

Abstract: Silicified shells with spines preserved allow analysis of spine distribution as a specific character in the genus Marginifera Waagen and confirm validity of Waagen9s (1884) six species. The animal lived with the ventral valve down, the adult shell partly buried, but many spines grew above the substrate prior to burial. Pseudopunctae are interpreted as seats of ciliate papillae or elongate setal follicles, as adaptation to partial burial in soft substrate. Auricular chambers, marginal ridges, and endospines provided effective protection against ingression of coarse or harmful particles. Productus opuntia Waagen is assigned to Echinauris Muir-Wood & Cooper; its habitat and adaptations are interpreted as similar to those of Marginifera. The stratigraphic position of the bed containing the late Permian guide ammonoid Cyclolobus proves to be lower than hitherto thought, thus extending the ammonoid9s range. A Guadalupe age for the Chhidru formation is suggested.

The genus Wewokella (Porifera) in the Pennsylvanian of Ohio

Abstract: Specimens of the sponge Wewokella solida Girty are reported from the upper Pottsville and lower Allegheny Groups in Ohio. Spicules of all specimens are composed of calcium carbonate. Conditions of high pH and(or) high temperature may have resulted in silica-carbonate replacement if the spicules were originally opaline silica. Marginally favorable habitats may have been present in Pennsylvanian epicontinental seas for representatives of the Hyalospongea. Specimens show evidence of strong current action and may have lived on a muddy bottom.

Size change in development and evolution

Abstract: Phylogeny is a succession of ontogenies, and the two have been compared by considering them in terms of rates of size change. In development, the larger the organism, the slower its rate of size increase. In evolution, the rates of size change can be put into three distinct categories: fast, medium, and slow. The fast changes occur over short pe- riods of time (1-10 thousand years) and are as likely to show size decrease as increase. The medium changes occur over longer time spans (5-20 million years) and are predomi- nantly or entirely instances of size increase. The slow changes occur over the entire span of organic evolution and represent the maximum size attained in various phyla, which again show an over-all increase. For ontogeny, a decrease in rate of size change is correlated with an increase in com- plexity, an increase in the number of gene actions. For evolution, it is correlated with an increase in the number of genetic changes required of the genome by natural selection in fluctuating environments.

Lorica composition of modern and fossil Tintinnida (ciliate Protozoa), systematics, geologic distribution, and some new Tertiary taxa

Abstract: Two superfamilies are proposed for the order Tintinnida: Codonellidea (new) contains the families Tintinnidiidae, Codonellidae, Codonellopsidae, Coxliellidae, and probably Dictyocystidae, Eppiplocylididae, Petalotrichidae. They have a pronounced ciliary membrane and a relatively solidly constructed lorica, commonly with spiral structures, and with agglutinated particles in the wall. Tintinnidea (emended) contains the remaining families, Cyttarocylididae, Ptychocylididae, Rhabdonellidae, Xystonellidae, Undellidae, and Tintinnidae. They lack a ciliary membrane; the lorica is thin, hyaline, and organic without agglutinated particles, and has vertical or transverse, not spiral, structures. Previously proposed superfamily Calpionellidea is not recognized. Two new genera and species of Codonellidae are described from upper Eocene of Mississippi.

Symmetry in conodont element-pairs

Abstract: Of the four symmetry classes of conodont element-pairs recognized herein, two involve asymmetry. Asymmetry in the conodont-bearing organism need not preclude the concept of a nektonic mode of life, but it is clear that each conodont element was not part of a mirror-imaged pair. Interestingly, three of the four possible symmetry classes of conodont element-pairs are currently known to exist among scolecodont element-pairs of the polychaete jaw apparatus. Although not of suprageneric importance, the symmetry classification of conodont element-pairs is helpful in conodont taxonomy and can be useful in deciphering conodont lineages.

Some aspects of colony development in corals

Abstract: Many peculiarities of growth and development in colonial metazoans are related to the fact that a true colony is a clone, composed of genetically identical individuals reproduced asexually from a single founding individual. In fossil colonies the close relationship of individuals may be difficult to prove, but it must be assumed for analysis to be meaningful. Intercolony variation is due to the interaction of genetic and environmental controls as in solitary organisms. Intracolony variation may be very limited because of the lack of genetic variation, but microenvironmental differences (situation within colony) may cause enough individual variation to mask the restrictive effect of genetic similarity. Study of the number of major septa in some Devonian solitary and colonial rugose corals shows significantly less variation within colonies than within “populations” or species of colonial or solitary forms. Greater variation within some colonies may result from either genetic or mechanical accidents. Septal number and diameter are closely correlated in populations and species, but analyses of individuals within colonies frequently show weak or no correlation. Available data suggest: 1) that septal-number variation may be genetically limited in rugose corals and 2) that the general assumption that number of septa is a function of diameter may be in error.

The evolution of ecological units above the population level

Abstract: Underlying the ecologic hierarchy is a genetic hierarchy that is ultimately based on nucleotides which are organized into units of heredity. From these units the ecological hierarchy proceeds to levels that include the individual organism, the niche, the ecosystem, the 9biome9, and the biosphere. Each level can be considered as a system of which the units of the preceding level form parts. Such systems can be described nearly independently. Each of these systems may evolve by means of changes in the relations among its largest subsystems. Evolution of the more inclusive levels includes changes in the relationships among the subsystems of all the lower levels as well. Thus, some information about the most inclusive level may be gained from studying the least inclusive. The entire hierarchy, however, evolves in concert, and study of the more inclusive systems may shed light upon pathways of evolution of the less inclusive.

Zoophycos, a polychaete annelid, Eocene of Greece

Abstract: Description of burrows, classification, restriction of genus to Z. brianteus, ecologic and morphologic interpretations, comparison with Recent forms

The Triassic echinoids of North America

Abstract: Triassic echinoids are rare, particularly in North America where only two species have been described [from California], both of which are based on [cidaroid] fragments which cannot be generically identified. These fragments are herein reillustrated and redescribed. More than two hundred specimens of a new genus and species, Lenticidaris utahensis, have been found in the Early Triassic Virgin Formation of Utah. This species belongs to the family Miocidaridae and is unique in having a highly flexible adapical surface.

Fossil tracks from the Green River Formation (Eocene) near Soldier Summit, Utah

Abstract: Numerous well-preserved bird, mammal, and insect-larva? tracks were discovered in the lowermost part of the delta facies of the middle Eocene Green River Formation. The area was probably a near-shore shelf area of the Eocene Uinta Lake that frequently became an emergent mudflat. The preservation of the tracks provides a record of an organic community that is not known from conventional skeletal remains in this area. The level to which animal tracks may be classified taxonomically depends upon the group represented, the geologic age of the tracks, the tracking conditions, and the variations resulting from differences among the individuals of a particular species.

Zoophycos, and a proposed classification of sabellid worms

Abstract: Zoophycos" are fossil prostomia of sedentary marine worms (Annelida, Seden- taria) from the family Sabellidae. The evidence presented in this study is based on a detailed investigation of the imprints of these worms observed in the Czechoslovakia Carpathians. In consideration of specimens collected in the Carpathians and literature studied, a classifica- tion of fossil Sabellids, based on the morphology of their prostomial parts, reveals three genera (Zoophycos Massalongo 1951, Palaeospira Pli/ka 1964, Spirographis Viviani 1805) and five species. In this study one new genus (Palaeospira) and two new species (P. ensigera and Spirographis carpatica) are proposed. The occurrence of fossil prostomial parts of Sabel- lidae is analogous to that of recent sabellid worms and indicates a shallow-water marine en- vironment with very rapid sedimentation.

Silurian to lower middle Devonian Chonetacea

Abstract: Three major groups of Llandoverian to Eifelian chonetids are recognized: the Chonetidae, the Anopliidae, and the Chonostrophiidae. The relationship of these groups to each other and to the enigmatic genera Notiochonetes and Allanetes are not known. Protochonetes is considered to have given rise to Strophochonetes, Chonetes, Parachonetes, Eccentricosta, Dawsonelloides n.g., and possibly Longispina; Chonetes to have given rise to Eodevonaria and Plebejochonetes n.g.; Plebejochonetes n.g. to Plicodevonaria n.g. Chonostrophia was derived from Chonostrophiella, Shagamella n.g. and Eoplicanoplia n.g. are considered to share a common ancestry, Shagamella n.g. gave rise to Anoplia; Eoplicanoplia n.g. to Plicanoplia n.g. which, in turn, gave rise to Cyrtoniscus n.g. Lower Devonian chonetids are notably provincial in their geographic distribution. Seven new genera are defined: Plebejochonetes n.g. from the lower Devonian and Eifelian of Europe & Turkey; Plicodevonaria n.g. from the lower Devonian and Eifelian of Europe, Turkey, Morocco, and Burma; Dawsonelloides n.g. from the lower Devonian of the northern Appalachians; Shagamella n.g. from the Ludlow of Britain and Venezuela; Eoplicanoplia n.g. from the Ludlow of North America; Plicanoplia n.g. from the lower Devonian of North and South America; and Cyrtoniscus n.g. from the lower Devonian of northeastern North America. The family Anopliidae is revised. The family Eodevonariidae Sokolskaja, is placed in the synonomy of the Chonetinae.

Notes on rostral teeth of ganopristine sawfishes, with special reference to texas material

Abstract: Bulk washing of marine sediments of the Gulf Coastal Plain, varying in age from Albian to Montian, has resulted in the recovery of rostral teeth of three genera of ganopristine sawfishes. The sample contains teeth of Sclerorhyncus, a genus not before reported from America. The collection is believed to demonstrate evolution within two genera; (1) teeth referred to Onchopristis dunklei from Albian deposits have fewer barbs along their posterior edge than otherwise identical teeth from Cenomanian deposits of Texas. (2) There is a gross enlarge- ment of the pulp cavity and decrease in the amount of osteodentine in the bases of Ischy- rhiza mira teeth from Turonian to Santonian. Certain species have geologic ranges which do not overlap and may prove to be useful in zonation.

Pleistocene ostracode zoogeography in Atlantic coast submarine canyons

Abstract: Twenty-five rock samples dredged from ten submarine canyons off the Atlantic coast of the United States have yielded [more than 50 species of] ostracodes that are interpreted to be of Pleistocene age. The taxonomiccomposition of the assemblages [in comparison with modern faunas] suggests that during times of lowered sea level the present boundary between cold- and mild-temperate faunal provinces, about 42 degrees north latitude, lay approximately 500 miles southwest, near 38 degrees north latitude.

A problematical coelenterate(?) from the Lower Cambrian, near Moraine Lake, Banff Area, Alberta

Abstract: Problematical tub-like structures from the Lower Cambrian Gog Group of Sentinel Pass, near Moraine Lake, Banff Area, Alberta, are referred to Bergaueria Prantl, and are interpreted as the resting burrows of a primitive coelenterate, possibly related to Edwardsia.

Echinoids of the Mesozoic families Collyritidae D'Orbigny, 1853 and Disasteridae Gras, 1848

Abstract: Disasteroid echinoids are members of the superorder Atelostomata characterized by a disjunct apical system. Recent studies have demonstrated that primitive disasteroids are endocyclic and that the transition to exocyclic forms can be traced in several lineages. The best documentation of the regular-irregular transition is within the Collyritidae. The Disasteridae as previously conceived is polyphyletic because the non-intercalary apical system evolved at least four times. The classification of the Atelostomata is revised to include these orders: Galeropygoida, new; Cassiduloida; Disasteroida, new; Holasteroida; Pourtalesioida, new; Spatangoida. Disasteroida includes the families: Pygorhytidae; Collyritidae; Disasteridae; Tithoniidae, new; Acrolusiidae, new.