Sacabamba is a town in the Cochabamba Department in central Bolivia. It is the capital of the fourth municipal section of Esteban Arce Province. At the time of census 2001 it had a population of 636. Jatun Mayu Instituto Nacional de Estadistica de Bolivia Map of Esteban Arce Province
County of Grant, Victoria
The County of Grant is one of the 37 counties of Victoria which are part of the cadastral divisions of Australia, used for land titles. It includes Geelong. Ballarat is on its north-western edge, it is bounded in the west by the Yarrowee River, on the north by the Great Dividing Range and on the east by the Werribee River. The county was proclaimed in 1853; the Darriwilian Age of the Ordovician Period of geological time is named for Darriwil parish in the county. Parishes within the county: Anakie, Victoria Ballark, Victoria Ballarat, Victoria Balliang, Victoria Bamganie, Victoria Barrarbool, Victoria Bellarine, Victoria Beremboke, Victoria Borhoneyghurk, Victoria Bulban, Victoria Bungal, Victoria Bungaree, Victoria Bungeeltap, Victoria Buninyong, Victoria Burtwarrah, Victoria Cargerie, Victoria Carrah, Victoria Carrung-e-murnong, Victoria Clarendon, Victoria Cocoroc, Victoria Conewarre, Victoria Coolebarghurk, Victoria Corio, Victoria Darriwil, Victoria Dean, Victoria Duneed, Victoria Durdidwarrah, Victoria Gherang Gherang, Victoria Gherineghap, Victoria Gnarwarre, Victoria Gorong, Victoria Gorrockburkghap, Victoria Jan Juc, Victoria Kerrit Bareet, Victoria Korweinguboora, Victoria Lake Lake Wollard, Victoria Lal Lal, Victoria Lara, Victoria Mambourin, Victoria Meredith, Victoria Modewarre, Victoria Moolap, Victoria Mooradoranook, Victoria Moorarbool West, Victoria Moorpanyal, Victoria Moranghurk, Victoria Moreep, Victoria Mouyong, Victoria Murgheboluc, Victoria Murtcaim, Victoria Narmbool, Victoria Paraparap, Victoria Parwan, Victoria Paywit, Victoria Puebla, Victoria Tutegong, Victoria Wabdallah, Victoria Warrenheip, Victoria Werribee, Victoria Woornyalook, Victoria Wormbete, Victoria Wurdi-Youang, Victoria Yaloak, Victoria Yowang, Victoria Vicnames, place name details Research aids, Victoria 1910 Map of the county of Grant showing colony and county boundaries, 1886.
National Library of Australia
Graptolithina is a subclass of the class Pterobranchia, the members of which are known as graptolites. These organisms are colonial animals known chiefly as fossils from the Middle Cambrian through the Lower Carboniferous. A possible early graptolite, Chaunograptus, is known from the Middle Cambrian. One analysis suggests. Studies on the tubarium of fossil and living graptolites showed similarities in the basic fusellar construction and it is considered that the group most evolved from a Rhabdopleura-like ancestor; the name graptolite comes from the Greek graptos meaning "written", lithos meaning "rock", as many graptolite fossils resemble hieroglyphs written on the rock. Linnaeus regarded them as'pictures resembling fossils' rather than true fossils, though workers supposed them to be related to the hydrozoans; the name "graptolite" originates from the genus Graptolithus, used by Linnaeus in 1735 for inorganic mineralizations and incrustations which resembled actual fossils. In 1768, in the 12th volume of Systema Naturae, he included G. sagittarius and G. scalaris a possible plant fossil and a possible graptolite.
In his 1751 Skånska Resa, he included a figure of a "fossil or graptolite of a strange kind" thought to be a type of Climacograptus. The term Graptolithina was established by Bronn in 1849 and Graptolithus was abandoned in 1954 by the ICZN. Since the 1970s, as a result of advances in electron microscopy, graptolites have been thought to be most allied to the pterobranchs, a rare group of modern marine animals belonging to the phylum Hemichordata. Comparisons are drawn with the modern hemichordates Cephalodiscus and Rhabdopleura, according to recent phylogenetic studies, rhabdopleurids are placed within the Graptolithina, they are considered an incertae sedis family. On the other hand, Cephalodiscida is considered a sister subclass of Graptolithina; some of the main differences between these two groups are that Cephalodiscida is not a colonial organism so there is not a common canal connecting all zooids, which have several arms while Graptolithina zooids have a pair. Other differences include the type of early development, the gonads, the presence or absence of gill slits, the size of the zooids.
However, in the fossil record where tubes are preserved, it is complicated to make the distinction between groups. Graptolithina includes two main orders and Graptoloidea; the latter is the most diverse, including 5 suborders. This group includes Diplograptids and Neograptids, groups that had a great development during the Ordovician. Old taxonomic classifications consider the orders Dendroidea, Camaroidea, Stolonoidea and Dithecoidea but new classifications embedded them into Graptoloidea at different taxonomic levels. Graptolites have a worldwide distribution; the preservation and gradual change over a geologic time scale of graptolites allow the fossils to be used to date strata of rocks throughout the world. They are important index fossils for dating Palaeozoic rocks as they evolved with time and formed many different species. Geologists can divide the rocks of the Silurian periods into graptolite biozones. A worldwide ice age at the end of the Ordovician eliminated most graptolites except the neograptines.
Diversification from the neograptines that survived the Ordovician glaciation began around 2 million years later. Some of the greatest extinctions that affected the group were the Hirnantian in the Ordovician and the Lundgreni in the Silurian, where the graptolites populations were reduced. In the late Ordovician extinction, a recovery event known as the Great Ordovician Diversification Event or GOBE, influenced changes in the morphology of the colonies and thecae, giving rise to new groups like the planktic Graptoloidea; each graptolite colony originates from an initial individual, called the sicular zooid, from which the subsequent zooids will develop. These zooids are housed within an organic tubular structure called a theca, coenoecium or tubarium, secreted by the glands on the cephalic shield; the composition of the tubarium is not known but different authors suggest it is made out of collagen or chitin. The tubarium has a variable number of branches or stipes and different arrangements of the theca, these features are important in the identification of graptolite fossils.
In some colonies, there are two sizes of theca, the authoteca and the bitheca, it has been suggested that this difference is due to sexual dimorphism. A mature zooid has three important regions, the preoral disc or cephalic shield, the collar and the trunk. In the collar, the mouth and anus and arms are found; as a nervous system, graptolites have a simple layer of fibers between the epidermis and the basal lamina have a collar ganglion that gives rise to several nerve branches, similar to the neural tube of chordates. All this information was inferred by the extant Rhabdopleura, however, it is likely that fossil zooids had the same morphology. An important feature in the tubarium is the fusellum, which looks like lines of growth along the tube observed as semicircular rings in a zig-zag pattern. Most of the dendritic or bushy/fan-shaped o
Cameroceras is a genus of extinct, giant orthoconic cephalopod that lived during the Ordovician period. It first appears during the middle Ordovician, around 470 million years ago, was a common component of the fauna in some places during the period, inhabiting the shallow seas of Laurentia and Siberia, its diversity and abundance became reduced following the Ordovician–Silurian extinction events, the last remnants of the genus went extinct sometime during the Wenlock. Cameroceras is a cephalopod, a taxon of molluscs that includes the octopuses and cuttlefish. From comparison with living cephalopods the shelled chambered nautilus, some inferences about the biology of Cameroceras can be made; the head of the animal would have been soft muscular tissue situated at the opening of the hard cone-like shell, with the mantle lying within the shell for protection. Tentacles would have grown from the base of the head like in a modern nautilus, these tentacles would have been used to seize and manipulate prey.
At the base of these tentacles within the buccal mass a hard keratinous beak would have bitten into the bodies of its prey, is assumed to have been strong enough to breach the prey's exoskeleton or shell. Within the beaks of modern cephalopods a radula, or'toothed' tongue is used to rasp out soft tissue from within the prey's shell; the partial shell of one giant Cameroceras yielded a total length estimated at the time at nearly 9 m. This estimate has since been revised downward quite a bit. Regardless of this estimate's degree of accuracy, this gargantuan cephalopod is thought to be among the largest known Paleozoic molluscs. Cameroceras has become a "wastebasket taxon" in which large orthoconic endocerids such as Endoceras and Meniscoceras were placed; this makes it difficult to describe Cameroceras as a distinct genus. Although the type species Cameroceras trentonense was first described by Conrad in 1842, since the generic term has had variable meaning. Hall, who named and described Endoceras in 1847 recognized C. trentonense but used Endoceras for other specimens of large endocerids from the Trenton Limestone of western New York state.
Cameroceras and Endoceras have been applied to different stages of the same species. Although Cameroceras takes precedence where the two refer to the same species, its vague application leaves Endoceras or other better-described genus the term of choice; the lifestyle and habits of Cameroceras can only be surmised. They were certainly stalkers and ambush predators that moved across the sea floor or lay in wait; the large rigid shell would have made maneuvering difficult. The larger ones were not active swimmers; the largest may have remained on the bottom without changing position. As with all endoceratids Cameroceras was weighted so as to be horizontally stable; this would have been achieved by the endocones in the apical portion of the siphuncle that would have compensated for the visceral mass forward in the body chamber. The endocones would have sealed off the more apical chambers from the siphuncle limiting changes in ballast to the more forward, centrally located, chambers; the result is. Cephalopod size Clarke, J.
M. 1897. The Lower Silurian Cephalopoda of Minnesota. In: E. O. Ulrich, J. M. Clarke, W. H. Scofield & N. H. Winchell The Geology of Minnesota. Vol. III, Part II, of the final report. Paleontology. Harrison & Smith, Minneapolis. Pp. 761–812. Flower, Rousseau H. 1955. Status of Endoceroid Classification. Journal of Paleontology 29: 329–371. Haines, Tim, & Chambers, Paul. 2005. The Complete Guide to Prehistoric Life. BBC Books, London. Sweet, Walter C. Cephalopoda—General Features in Treatise on Invertebrate Paleontology, Part K, Mollusca 3. Geological Society of America, University of Kansas Press. Page K5. Teichert, C. 1964. Endoceratoidea in Treatise on Invertebrate Paleontology, Part K, Mollusca 3. Geological Society of America, University of Kansas Press. Page K174. Teichert, C. and B. Kümmel 1960, Size of Endocerid Cephalopods. Comp. Zool. No. 128, 1–7
A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, petrified wood, coal, DNA remnants; the totality of fossils is known as the fossil record. Paleontology is the study of fossils: their age, method of formation, evolutionary significance. Specimens are considered to be fossils if they are over 10,000 years old; the oldest fossils are around 3.48 billion years old to 4.1 billion years old. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils; the development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host. There are many processes that lead to fossilization, including permineralization and molds, authigenic mineralization and recrystallization, adpression and bioimmuration.
Fossils vary in size from one-micrometre bacteria to dinosaurs and trees, many meters long and weighing many tons. A fossil preserves only a portion of the deceased organism that portion, mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may consist of the marks left behind by the organism while it was alive, such as animal tracks or feces; these types of fossil are called trace ichnofossils, as opposed to body fossils. Some fossils are called chemofossils or biosignatures; the process of fossilization varies according to external conditions. Permineralization is a process of fossilization; the empty spaces within an organism become filled with mineral-rich groundwater. Minerals precipitate from the groundwater; this process can occur in small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce detailed fossils. For permineralization to occur, the organism must become covered by sediment soon after death, otherwise decay commences.
The degree to which the remains are decayed when covered determines the details of the fossil. Some fossils consist only of skeletal teeth; this is a form of diagenesis. In some cases, the original remains of the organism dissolve or are otherwise destroyed; the remaining organism-shaped hole in the rock is called an external mold. If this hole is filled with other minerals, it is a cast. An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull; this is a special form of mold formation. If the chemistry is right, the organism can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it. If this happens before significant decay to the organic tissue fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
Replacement occurs. In some cases mineral replacement of the original shell occurs so and at such fine scales that microstructural features are preserved despite the total loss of original material. A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite. Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state; this chemical change is an expression of diagenesis. What remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression. However, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil. In many cases, however and impressions occur together. For instance, when the rock is broken open, the phytoleim will be attached to one part, whereas the counterpart will just be an impression.
For this reason, one term covers the two modes of preservation: adpression. Because of their antiquity, an unexpected exception to the alteration of an organism's tissues by chemical reduction of the complex organic molecules during fossilization has been the discovery of soft tissue in dinosaur fossils, including blood vessels, the isolation of proteins and evidence for DNA fragments. In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles associated with soft tissues recovered from dinosaur fossils. Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues. However, a older study based on eight taxa ranging in time from the Devonian to the Jurassic found that reasonably well-preserved fibrils that represent collagen were preser
Philosophical Transactions of the Royal Society B
Philosophical Transactions of the Royal Society B: Biological Sciences is a biweekly peer-reviewed scientific journal published by the Royal Society. The editor-in-chief is John Pickett; each issue covers a specific area of the biological sciences. Each issue aims to create an original and authoritative synthesis bridging traditional disciplines, which showcases current developments and provides a foundation for future research and policy decisions; each issue is edited by one or more expert guest editors. The themes fall into one of four general categories: Cell and Development Health and Disease Environment and Evolution Neuroscience and CognitionAll articles become accessible one year after their publication date. Philosophical Transactions of the Royal Society was established in 1665 by the Royal Society and is the oldest scientific journal in the English-speaking world. Henry Oldenburg was appointed as the first secretary to the society and he was the first editor of the society's journal.
In 1887 the journal expanded to become two separate publications, one serving the physical sciences, Philosophical Transactions of the Royal Society A: Mathematical and Engineering Sciences, the other focusing on the life sciences, Philosophical Transactions of the Royal Society B: Biological Sciences. Nowadays, both journals publish themed issues and discussion meeting issues, while individual research articles are published in the sister journal Proceedings of the Royal Society; the journal celebrated its 350th anniversary in 2015. To commemorate this event it published a special collection of commentaries on landmark papers from the archive by scientists such as Antonie van Leeuwenhoek, Hans Sloane and Alan Turing. Official website Royal Society Publishing 350th anniversary History of Philosophical Transactions
In geology, the Arenigian refers both to a time interval during the Lower Ordovician period and to the suite of rocks which were deposited during this interval. The term was first used by Adam Sedgwick in 1847 with reference to the "Arenig Ashes and Porphyries" in the neighbourhood of Arenig Fawr, in Merioneth, North Wales; the rock-succession in the Arenig district has been recognized by W. G. Fearnsides; the above succession is divisible into: A lower series of gritty and calcareous sediments, the "Arenig Series" as it is now understood. It was to the middle series that Sedgwick first applied the term "Arenig". In the typical region and in North Wales the Arenig series appears to be unconformable upon the Cambrian rocks; the Arenig series is represented in North Wales by the Garth Grit and Ty Obry beds, by the Shelve series of the Corndon district, the Skiddaw Slates of the Lake District, the Ballantrae Group of Ayrshire, by the Ribband Series of slates and shale in Wicklow and Wexford. It may be mentioned here that the "Llanvirn" Series of H. Hicks was equivalent to the bifidus shale and the Lower Llandeilo Series.
In the geologic timescale, the "Arenig" or Arenigian refers to an age of the Lower Ordovician epoch, between 478.6 ± 1.7 and 471.8 ± 1.6 million years ago, contemporary with the more proposed Floian by the ICS, based on a section in Sweden and with the same boundaries. The Arenigian and Floian are the upper part of the Lower Ordovician and follow the Tremadocian, the lower part. Either is followed by the Middle Ordovician ICS Dapingian or by the Llanvirnian of older chronologies; the Arenigian and equivalent Floian are represented in North America by the upper three stages of the Canadian, followed by the Middle Ordovician Whiterockian, the lower part of the now shortened Chazyan. The Arenig group was deposited during a sudden worldwide rise in sea level resulting in widespread marine transgression; the early Ordovician surge in marine diversity began around this time. Incertae sedis brachiopods of the FloianEurorthisina TegulellaAcrotretida of the Floian Lingulida of the Floian Orthida of the Floian Paternida of the FloianDictyonitesPentamerida of the Floian Strophomenida of the Floian Trimerellida of the FloianDinobolus ActinoceridaMetactinoceras Ordosoceras Polydesmia The following is a list of Actinocerid genera whose fossils are geochronologically found first in upper Arenig strata.
These genera may survive into portions of the Arenig stage, or into geological stages. This list should not be thought of in terms of the lifespan of the genera included. Orthocerids of the FloianEobactritesBarrandeocerida of the FloianPlectocerasEllesmerocerida of the Floian Endocerida LowerThe following is a list of Endocerid genera whose fossils are geochronologically found first in lower Arenig strata; these genera may survive into portions of the Arenig stage, or into geological stages. This list should not be thought of in terms of the lifespan of the genera included. UpperThe following is a list of Endocerid genera whose fossils are geochronologically found first in upper Arenig strata; these genera may survive into portions of the Arenig stage, or into geological stages. This list should not be thought of in terms of the lifespan of the genera included. Intejocerida of the FloianBajkaloceras Evencoceras Intejoceras RossocerasOncocerids of the FloianPhthanoncoceras ValhallocerasNautiloids of the Floian TarphyceridaDeltoceras Pseudancistroceras SeelyocerasLower Upper Trilobites of the FloianCanningella Gogoella Macrogrammus Priceaspis ThymurusAgnostida of the Floian'Galbagnostus GeragnostellaAsaphida of the Floian Corynexichida of the Floian Lichida of the Floian Odontopleurida of the Floian Phacopida of the Floian Proetida of the Floian Ptychopariida of the Floian palaeos