Showing papers in "Journal of Paleontology in 1966"

Geometric analysis of shell coiling; general problems

Abstract: Among the shells of invertebrates that exhibit spiral growth, differences in form can be expressed by differences in geometric parameters. If three parameters are considered at a time, the spectrum of possible shell forms may be shown by a block diagram. Analog and digital computer constructions make it possible to visualize shell forms that are theoretically possible but do not occur in nature. Actual species are not randomly distributed in the total spectrum of theoretically possible forms. Functional and evolutionary groups are confined to discrete regions of the spectrum. For example, a bivalve must have non-overlapping whorls in order to have a functional hinge. This fact restricts the geometric range of both brachiopods and bivalved molluscs. Ontogenetic change in coiling geometry may be interpreted as compensation for effects of increase in absolute size during growth.

Coral growth-rate, an environmental indicator

Abstract: Branching hermatypic corals, Acropora cervicornis (Lamarck) were transplanted into two areas of the Florida reef tract where they do not normally grow. The growth-rate of these corals and a control group on a thriving reef was measured twelve times between December 1960 and February 1962. Average growth-rate of the transplanted corals was less than one half that of the control group, which grew at 10 cm per year. Growth-rates, however, showed considerable variation. During a 2-month period one transplanted group grew as fast as the control group, but after 10 months died when the water temperature dropped to 13.3 degrees C. Seasonal fluctuations in growth at all stations could be correlated in a general way to temperature fluctuations . . . Growth was greatest between 28 degrees and 30 degrees C. The results suggest that the method may be used as a standard ecological tool for determining growth tolerances of other reef-building organisms.

Phylogeny and distribution of Ordovician trilobites

Abstract: Shortly before or during Tremadoc time the majority of pre-existing trilobite families died and were replaced by new, short-lived groups and early members of dominant Ordovician families. Endemic forms define six faunas separated into northern and southern provinces, without regard for enclosing lithic type. Constancy of distribution from Arenig to Llandeilo implies physical stability. Reduced endemism in the Caradoc and Ashgill probably reflects reduced barriers and broad oceanic circulation.

Upper Devonian conodonts from the Canning Basin, Western Australia

Abstract: All late Devonian conodonts available from sedimentary facies of the Lennard Shelf, Canning basin, Western Australia, are described The maximum abundance of conodonts is found in direct association with ammonoids in the inter-reef facies represented by the Gogo formation, and in the fore-reef and inter-reef facies of the Virgin Hills formation Associations of certain conodont and ammonoid taxa are identical with those in the classic antipodal Rhenish Schiefergebirge of Germany Distribution patterns show that the conodont and ammonoid zones are geologically homochronous on a mondial basis Playfordia ngen (conodont) and Ancyrodella rotundiloba alata nsubsp are described

New Pennsylvanian platform conodonts from southwestern United States

Abstract: Previously undescribed Early Pennsylvanian (Morrowan and Atokan or Derryan) platform conodonts are described from eight localities in Oklahoma, Texas, and Nevada. The 11 new species are assigned to six genera, of which Declinognathodus and Rhachistognathus are new. The new condont taxa are: Cavusgnathus spatha, C. transitoria, Gnathodus defectus, Declinognathodus nevadensis, Idiognathodus humerus, I. incurvus, Streptognathodus angustus, S. anteeccentricus, S. parvus, S. suberectus, and Rhachistognathus prima.

Silurian pentameroid brachiopods preserved in position of growth

Abstract: Articulated specimens of Pentamerus oblongus and Stricklandia lens occur in a vertical position, umbones down, in blocks collected from a bed of late Llandovery age [Red Mountain Formation] in Alabama and from the Lower Llandovery of Scotland, respectively. These brachiopods are in their original position of growth, as indicated by growth irregularities in many specimens caused by proximity to their neighbors. Ample attachment surface was available in the form of disarticulated valves which are preserved just beneath the umbones of the specimens; the delthyria of these pentameroids are covered in such a way by the umbones of the brachial valves that it seems likely that their pedicles atrophied during ontogeny.

Pennsylvanian and Permian fusulinids of the Bird Spring Group from Arrow Canyon, Clark County, Nevada

Abstract: Fusulinids from approximately 2,500 feet of Morrowan (Pennsylvanian) through Wolfcampian (Permian) rocks are exposed in Arrow Canyon. The Morrowan and older fusulinids are noted but not described. Atokan fusulinids include Paramillerella, Millerella, Profusullinella, and Fusulinella; Desmoinesian fusulinids include Wedekindellina, Fusulina, Eoschubertella, and Bartramella; Missourian fusulinids include Pseudofusulinella, Oketaella, and Triticites; Virgilian fusulinids are all Triiticites; and Wolfcampian fusulinids include Triticites, Oketaella, Schwagerina, Pseudofusulina(?), and Pseudoschwagerina.

Allometry in pleistocene land snails from bermuda: the influence of size upon shape

Abstract: Size increase in ontogeny and phylogeny necessitates correlated modification of shape in order to preserve adequate adaptation in the expanded size range. The direction of these changes in shape can often be predicted. The allometric power function, y=bxk, ade- quately describes most size-correlated changes of proportions. A high value of k in this equa- tion limits possibilities for size increase, since continual relative enlargement of the y-dimen- sionsoon leads to unwieldy proportions. Alternately, k may decrease at larger sizes, permitting an expanded size range. Height versus width allometry is described in the dome-shaped Bermudian Pleistocene pulmonate Poecilozonites. The principle of negative correlation of size and k holds among all species studied; larger species have progressively lower k values. The extrapolation of the smallest species' mean k to the size of the largest species would produce a snail 20 times higher than wide. Sayles' specimens of P. dalli are conspecific with his P. cupula; his P. dalli is an artificial category constructed for individuals at the upper extreme of the k distribution which, due to the high k values, are smaller and higher spired than average specimens of P. cupula. Two atypical specimens of P. nelsoni grow with abnormally high k early in ontogeny. In order to reach adult widths and avoid disadvantageously high spires, k is sharply reduced during ontogeny. The principle of negative correlation of size and k holds widely in the literature of both ontogenetic and phylogenetic allometry. Examples are presented from the Brachiopoda, Crustacea, Insecta, Vertebrata and from the morphology of fluvial ripples. The principle can be used as a criterion for determining whether evolutionary changes in the k parameter are common solutions to size-imposed problems or special adaptations to particular features of the organism's mode of life.

On the structure and relationships of graptolites

Abstract: The morphology of the colony in the different graptolite orders is variable but their essential characters such as the initial stages of development, the fine structure, and chemical composition of the skeleton are the same in all representatives of the group. A comparison of graptolites with coelenterates indicates that their similarities are only an expression of convergence. The arguments of Bohlin and observations of Decker are considered erroneous. The fine structure of the skeleton, its chemical composition (protein substances), and the manner of zooid budding are the same in graptolites and in pterobranchs demonstrating that the Graptolithina and the Pterobranchia are closely related groups of the phylum Hemichorda.

Seymouria from the lower Permian of southeastern Utah, and possible sexual dimorphism in that genus

Abstract: A new species of Seymouria, S. sanjuanensis, is described on the basis of specimens from the Lower Permian Organ Rock Shale, Cutler Group, San Juan County, Utah. Compari- son of specimens of the different species of Seymouria corroborates earlier evidence presented by T. E. White for osteological sexual dimorphism in Seymouria. In addition to the distinction drawn by White wherein the haemal arches begin farther back in the caudal column in the males, possible other differences are that in the males the interorbital breadth is less, the maxillary bone is deeper, and the dentition in general and "canine" teeth in particular are more prominent. This analysis of dimorphism is supported by the studies of Z. V. Spinar on the discosauriscid seymouriamorphs. In the greater development of the dorsal surfaces of the postparietal and tabular bones, S. sanjuanensis is more primitive than S. baylorensis from the Clear Fork Group of Texas. A specimen of Seymouria sp. from the Wichita Group of Texas indicates that two lines of Seymouria, one in the Four Corners area and one in the Midconti- nent, may have evolved independently of one another after separation by a barrier to faunal exchange.

Wall structure, systematics, and phylogeny studies of Cenozoic planktonic Foraminifera

Abstract: Three types of wall microstructure were found: walls of identical, nearly parallel calcite crystals perpendicular to test surface; walls of short, prominent crystals surrounded within the wall by finer crystals; and walls in which some crystals are elongated as spines and surrounded within the wall by finer crystals. These microstructures and the basic type of chamber coiling are utilized for recognition of four families: Globorotaliidae, with eleven genera in two subfamilies (Globorotaliinae and Candeininae), have trochoid tests whose walls consist of identical crystals; Hantkeninidae, with five genera in two subfamilies, are initially planispiral, and their walls have identical crystals; Catapsydracidae, with four genera, have walls of short, prominent crystals; and Globigerinidae, with thirteen genera, have walls in which some crystals are elongated into spines.

The discrimination of morphological groups of Elphidium (Foraminifer) in Long Island Sound through canonical analysis and invariant characters

Abstract: The morphological groups Elphidium incertum (Williamson), E. incertum of Cushman (not Williamson), E. clavatum Cushman, E. subarcticum Cushman were compared by observing the external morphology of representative populations from Long Island Sound. These observations suggested that only E. incertum (Williamson), E. clavatum Cushman, and E. subarcticum Cushman are distinct enough to be recognized as species. In order to test the hypothesis the four morphological groups were discriminated on the basis of external morphol- ogy; eight of the characters by which the groups are distinguished were measured and/or scored on 30 individuals from each group. These variates were then compared along canonical axes. The canonical analysis revealed that only the groups E. incertum (Williamson), E. clavatum Cushman, and E. subarcticum Cushman are clearly recognizable. Further comparison was possible through the consideration of the presence or absence of the invariant characters: 1, organic inner lining; 2, radial wall structure; 3, granular wall structure; E. incertum of Cushman and E. clavatum Cushman possess 1 and 2, but not 3. E. incertum (Williamson) possesses 3, but not 1 and 2 whereas E. subarcticum Cushman possesses 2, but not 1 and 3. Consideration of the invariant characters is then in complete agreement with the observations and analysis of the external morphology. All evidence leads to the conclusion that three species are represented here.

Functional morphology of calceocrinidae with description of some new species

Abstract: A survey of calceocrinid paleoecology indicates that the group exploited a "run- ner" mode of life as postulated by Jaekel. The unique feature of the Calceocrinidae is the hinge and muscular articulation between the basal and radial circlets, which allows the radial circlet, tegmen and arms to be rotated relative to the basals and stem. During life the calceocrinid stem was located on the substrate. With the hinge in the closed position the arms were closed and directed more or less parallel to the stem and sea floor. With the hinge in the open or feeding position the arms and radials were directed approximately normal to the stem. In the feeding position the arms were open and spread out like an open fan, which al- lowed a large volume of water to be covered by the arms. Evolutionary trends in the calceocrinid dorsal cup are largely related to the "runner" habit. On the other hand, evolutionary trends in the arms led to the development of a larger and better-protected food gathering system and closely parallel those of crinoids exploiting the "normal" crinoid habit. Six new species of calceocrinids are described: Calceocrinus constrictus, C. multibifurcatus, Grypocrinus multibrachiatus, Halysiocrinus septarmatus, and H. springeri. Calceocrinus pustu- losus Johnson is described and illustrated for the first time. Grypocrinus multibrachiatus n.sp. enables the generic diagnosis of Grypocrinus to be ex- panded and suggests that Synchirocrinus may be polyphyletic. The morphology of Halysio- crinus septarmatus n.sp. suggests that Halysiocrinus is descended from Deltacrinus or its ancestral stock. Calceocrinus multibifurcatus n.sp. represents a previously unrecorded morphological type of Calceocrinus. The occurrence of undoubted specimens of Anulocrinus and possibly specimens of Calceo- crinus in the Black River stage of Oklahoma presents a problem in calceocrinid phylogeny and resurrects debate as to whether Anulocrinus or Cremacrinus represents the ancestral stock of the family.

Conodonts and biostratigraphy of the Lower and Middle Devonian of Nevada and Utah

Abstract: Formations of Lower and Middle Devonian age in eastern and central Nevada, and in central and western Utah were studied and sampled at many localities. Significant conodont faunas were obtained from all formations sampled except the Sevy and Lone Mountain Dolomites. Age relationships interpreted from the faunal discoveries suggest that definite time lines can be projected from central Utah to central Nevada for part of the Paleozoic rocks and that these time lines cut across most of the formations.

Stratigraphic, geographic, and evolutionary development of the conodont genus Gondolella

Abstract: The genus Gondolella has been defined as a gondola-shaped platform conodont and is known to be present in rocks of Pennsylvanian, Permian, and Triassic age in many parts of the world. Some 33 names have been proposed of which 19 are considered valid. The earlier species described are from the Desmoinesian Series of Midcontinent North America and the latest are from the Upper Triassic of North America, Europe and Asia. Reduction in size, loss of ridged platform, and narrowing of basal groove accompanied by modification of basal pit are the evolutionary trends noted. All known species have short stratigraphic ranges.

The Moore Pit local fauna; Pleistocene of Texas

Abstract: Slaughter et al. (1962) previously described several Pleistocene vertebrate local faunas from separate commercial pits in the second (T-2) terrace above the floodplain of the Trinity River at Dallas, Tex. Since that time, extensive commercial excavation has joined several of these pits. As it is now possible to trace the various levels from one to the other and as a scientific excavation at the Moore Pit has produced every species known from the other localities, all are brought under a single assemblage. The age of this assemblage is known to be in excess of 37,000 years, but falls within an old valley fill believed to have formed between 50,000 and 25,000 B.P. (Before Present). A complete and extended faunal list is included although only the new material is described. The climatic inference of the fauna and its significance to other related faunal assemblages is discussed.

Digitate algal stromatolite structures from the Cambrian and Ordovician of Missouri

Abstract: Oolitic and dolarenitic facies of Upper Cambrian and Lower Ordovician formations in Missouri contain abundant algal stromatolites, which are digitate in vertical section and meandrine to subcircular in plan view. Environmental factors and problems of classification are discussed. Application to these structures of the names Collenia or Gymnosolen is decried, and use of simple descriptive terms is supported. Thus the term 9digitate stromatolite9 is used for the structures under discussion.

Protospongia hicksi Hinde from the Middle Cambrian of western Utah

Abstract: A large, well preserved fragment of the lyssakid sponge was collected from the Middle Cambrian Marjum Formation in the House Range of western Utah. Molds of articulated spicules occur in a slab of hornfels. The specimen consists of five ranks of cruciform stauract spicules and a layer of rod-like spicules. Spicule rays form roughly rectangular quadrules, averaging 1 cm, 5 mm, 2 mm, 1 mm, and 0.5 mm for each of the five orders. Largest spicules overlie all smaller ones in regular progression. Individual spicules are composed of four gently tapering rays and each overlap adjacent spicules from one-third to two-fifths their length. Spicules were probably united by fleshy material. There is no evidence of interweaving between orders.

Permian fusulinidae of the Franklin Mountains, New Mexico-Texas

Abstract: Restudy of the Permian rocks of the Franklin Mountains supports a three-fold subdivision based on correlation with the Hueco Canyon Formation, Cerro Alto Limestone, and Alacran Mountain Formation in the Hueco Mountains, Texas. The Hueco Canyon and Alacran Mountain Formations of the Franklin Mountains contain distinctive assemblages of fusulinid species directly comparable to those in the type localities. The Cerro Alto Formation is apparently barren of fusulines. Both the Hueco Canyon and Cerro Alto Formations are wholly within the 9zone of Pseudoschwagerina9 as is such portion of the Alacran Mountain Formation as can be observed. The top of the formation is not exposed and the position of the Wolfcamp-Leonard boundary is indeterminate.

Cretaceous planktonic foraminifers from Dry Creek, Tehama County, California

Abstract: Well-preserved foraminiferal faunas have been recovered from the upper 14,300 feet of Mesozoic sediments that are exposed along Dry Creek, Tehama County, Calif. These foraminifers and supplementary megafossil data permit correlation of these sediments with the Hauterivian-Barremian to Turonian Stages of the standard Cretaceous section of Europe. The fauna of coiled planktonic foraminifera includes 27 species and subspecies, of which five are new. New species described herein are: Rotalipora tehamaensis, Globotruncana roddai, Hedbergella beegumensis, H. murphyi, and H. quadrata.

Megafauna of the upper Miocene Castaic Formation, Los Angeles County, California

Abstract: About 100 species, mostly pelecypods and gastropods, with smaller numbers of scaphopods, brachiopods, echinoderms, barnacles, bryozoans and vertebrates occur in the Castaic, many of them farther south than previously reported in the upper Miocene. Many of the Castaic taxa also are found in the Recent Panamanian Molluscan Province, indicating that the Castaic Formation was deposited near the northern limit of the late Miocene equivalent of that province.

Calliasterella americana, a new starfish from the Pennsylvanian of Illinois

Abstract: Starfish from the Pennsylvanian LaSalle Limestone of Illinois are the first species of Calliasterella to be found outside Russia. The type and only previously known species, C. mira, was described in 1879 from Pennsylvanian strata near Moscow. Our specimens are much better preserved, even though in death the arms curled inward to conceal the ambulacrals and most of the adambulacrals. The madrepore is known for the first time, and the shape of the aboral side of the disk is established. Our species differs from C. mira in having less acuminate corners on disk plates, scattered tubercles instead of a paxillary ridge on each aboral arm plate, and differently shaped supramarginals, axillaries, and adambulacrals. Aborally, this hemizonidan starfish bears a striking similarity to the phanerozonidan Protopalaeaster, and many plates appear homologous.

Camptostroma, an Early Cambrian supposed scyphozoan, referable to Echinodermata

Abstract: New material from the Kinzers Formation of Pennsylvania shows characters strongly suggestive of Echinodermata. The probable medusoid shape suggests a bathypelagic of planktonic habitat. The new class, Camptostromatoidea, is most closely related to Holothuroidea, although its proper place in the Echinodermata has not yet been determined.

The occurrence of stigmata in a Carboniferous scorpion

Abstract: A recent examination of Palaeopisthacanthus schucherti Petrunkevitch revealed the presence of stigmata and lateral eyes, and the absence of any postabdomen in the available material. A new diagnosis of the genus and diagnosis and description of the species are given.

Stringocephalus, ontogeny and distribution

Abstract: Study of a growth series of Devonian brachiopods belonging to the genus Stringocephalus indicates that the genus may have been derived from the subgenus Geranocephalus (Stringominus) of the family Stringocephalidae though it is only hypothetical. Stratigraphically the family Stringocephalidae arose from one or more ancestors in the Eifelian. The genus Stringocephalus has a worldwide distribution, from western Australia and Asia to north Africa, western Europe, and southern England, as well as in Indiana.

Cope's Rule and Precambrian and Cambrian invertebrates

Abstract: The phyletic trend toward increase in size of invertebrates (Cope9s Rule) is invoked to account for the sudden appearance of shelly forms in the Cambrian Earlier forms may have been too small and poorly organized to secrete shells

Camelus thomasi from the northern Sudan and its bearing on the relationship C. thomasi-C. bactrianus

Abstract: Discovery of a Camelus thomasi from northern Sudan, and a detailed study of the relationship between C. thomasi, C. bactrianus and C. dromedarius indicate that while C. thomasi and C. bactrianus belong to the Pleistocene Asiatic camels, C. thomasi differs strikingly from C. dromedarius and has no relationship with it. C. thomasi, which yielded the domesticated C. bactrianus, migrated into southern Europe during the Pleistocene epoch and apparently penetrated rather far into Africa.

Rare marine reptiles from the Cretaceous of New Jersey

Abstract: New finds from the Navesink greensand (Maestrichtian) of Burlington County, New Jersey, include the first-known frontal bone of the mosasaurine lizard Halisaurus platypondylus and a vertebra of Mosasaurus (Clidastes) conondon. A peripheraal bone of the toxochelyid saw-turtle Prionochelys demonstrates the survival of this genus into Maestrichtian time on the Atlantic seaboard.

Crystallographic data for echinoid coronal plates

Abstract: Crystal orientation data for ambulacral and interambulacral plates of 135 fossil and Recent species are presented. This brings the total number of species with known coronal plate crystallography to 252. The new sample is dominated by species that have either per- pendicular, tangential, or a combination of perpendicular and tangential c-axes in the coronal plates. Seventeen species in six families, however, exhibit ontogenetic variation in crystal orientation. Ontogenetic variation in the Arbaciidae and Toxopneustidae is distinct from that in the Echinometridae, Strongylocentrotidae, Conulidae, and Oligopygidae. The new data support the placement of the Oligopygidae in the order Holectypoida (as suggested by Durham & Melville, 1957) but raise questions as to the oligopygid affinities of the genus Haimea. The family Arbaciidae is extremely heterogeneous crystallographically; the data suggest that the family is polyphyletic. Variation in arbaciid crystallography is in good agreement with Mortensen's informal division of the family into five "groups."

Eurypterids from the Silurian of West Virginia

Abstract: Reclassification within the family Hughmilleriidae is proposed on the basis of morphological information gained through study of a new collection of eurypterids from the [Upper] Silurian rocks of West Virginia. Two new genera, Pittsfordipterus (type species: Hughmilleria phelpsae Ruedemann 1919, Vernon Shale of New York) and Bassipterus (type species: Bassipterus virginicus n. gen., n. sp., Wills Creek Formation of West Virginia), are proposed. Drepanopterus nodosus n. sp., Erettopterus (Truncatiramus) exopthalmus n. sp., morphological details of Waeringopterus cumberlandicus cumberlandicus (Swartz) and Parahughmilleria bellistriata (Kjellesvig-Waering) are described and illustrated. Measured sections of the Wills Mountain, Elkhorn Mountain and Hanging Rock Anticlines are included.