Muscle scars and mode of life of Carinaropsis (Bellerophontoidea, Gastropoda) from the Ordovician of Tennessee

1993 ◽  
Vol 67 (4) ◽  
pp. 528-534 ◽  
Author(s):  
John S. Peel
Keyword(s):  
General Shape ◽  
Mode Of Life ◽  
First Time

Muscle scars are described for the first time in the Ordovician bellerophontoidean gastropod Carinaropsis Hall. Silica replicas from the Cannon Limestone of Tennessee preserve a pair of muscle scars, with a single elongate scar located on each umbilico-lateral angulation of the shell interior more than half a whorl back from the apertural margin. The scars are similar in general shape and position to muscle scars described in Bellerophon de Montfort and the pleurotomarioidean Porcellia woodwardi (Sowerby). In addition to supporting the soft parts within the widely expanded shell, the characteristic internal septum of Carinaropsis probably facilitated clamping of the shell aperture against the substrate.

scholarly journals Ascocerid cephalopods from the Hirnantian?–Llandovery stages of the southern Paraná Basin (Paraguay, South America): first record from high paleolatitudes

2018 ◽  
Vol 93 (1) ◽  
pp. 37-47
Author(s):  
M. Cichowolski ◽  
N.J. Uriz ◽  
M.B. Alfaro ◽  
J.C. Galeano Inchausti
Keyword(s):  
Rare Condition ◽  
First Record ◽  
High Latitudes ◽  
Stage Of Development ◽  
Intracratonic Basins ◽  
Mode Of Life ◽  
Paraná Basin ◽  
Parana Basin ◽  
First Time ◽  
Juvenile Shell

AbstractAscocerid cephalopods are described for the first time from high paleolatitudes of Gondwana. Studied material was collected from the Hirnantian?–Llandovery strata of the Eusebio Ayala and Vargas Peña formations, Paraná Basin, southeastern Paraguay. The specimens are poorly preserved and were questionably assigned to the subfamily Probillingsitinae Flower, 1941, being undetermined at genus and species rank because diagnostic characters are not visible. A particular feature seen in our material is the presence of both parts of the ascocerid conch (the juvenile or cyrtocone and the mature or brevicone) joined together, which is a very rare condition in the known paleontological record. The specimens are interpreted as at a subadult stage of development because fully grown ascocerids would have lost the juvenile shell. A planktonic vertical migrant mode of life with a subvertical attitude is proposed for the juvenile, and a horizontal demersal nektonic mode for the adult form, as has been previously suggested. A subvertical orientation near the bottom is proposed for the subadult stage. We suggest that the immigration of ascocerids to southwestern Gondwana was possible through ocean currents that would carry the planktonic juveniles from low to high latitudes during the end-Ordovician postglacial transgression that flooded the intracratonic basins of the region.

MICROMORPHOLOGICAL STRUCTURE OF SEEDS IN SOME SPECIES OF LATHYRUS L. IN SOUTH CAUCASUS (AZERBAIJAN)

2020 ◽  
Vol 6(72) (1) ◽  
pp. 14-25
Author(s):  
G. F. Allahverdiyeva ◽  
A. M. Asgarov
Keyword(s):  
Side Surface ◽  
Morphological Characters ◽  
Morphological Properties ◽  
South Caucasus ◽  
General Shape ◽  
Taxonomic Importance ◽  
The Status ◽  
Different Populations ◽  
First Time ◽  
Electronic Microscope

For the first time, micromorphology structure of seeds in 10 species (L. annuus, L. cicera, L. hirsutus, L. tuberosus, L. miniatus, L. pratensis, L. laxiflorus, L. aphaca, L. nissolia, L. sphaericus) belonging to sections (Lathyrus, Pratensis, Aphaca, Nissolia, Linearicarpus) of Lathyrus L. collected from various regions of Azerbaijan were analysed. Seed samples of 10 species were taken for analysis from different biotopes and different populations located away from one-another. Collected seed materials were gathered in special sterile paper bags and their moisture was dried with silicagel substance in laboratory conditions. During the research, morphological characters, as well as general shape, size and colour of seed, length and width of hilum were identified under Leica EZ4D stereomicroscope. The largest seeds have been measured in Lathyrus (L. cicera 4,4–5,0 mm) section and the smallest seeds in Nissolia (L. nissolia 1,8–2,3 mm) section. The longest hilum belongs to L. miniatus 1,8–2,8 mm and the smallest in L. Nissolia 0,4–0,7 mm. The width hilum was measured in L. annuus (0,7–1,0 mm) and the narrow hilum L. nissolia (0,1–0,3 mm). Mature seed (2–3) samples were selected from each type under the SEM, the seeds were placed on stools with double-sided adhesive tapes and covered with gold powder through the JEOL JFC1600 ion-spray device for 1 to 2 minutes. Seed samples were researched on the side surface. The photos of the surface of seeds were taken in a 3000× size in JEOL JSM6610 lv electronic microscope, and structural analysis of the different places of their surfaces was conducted. The results showed that the microscopic research of the surface of seed is of taxonomic importance and is used in specification of the status of sections. The morphological properties such as surface structure, hilum length and width, papillae features can be used to differentiate some sections and species, but seed size, general shape seed and hilum, seed colour are not characteristics can be used to differentiate some sections.

The hydranth of Salacia tetracythara (Cnidaria: Hydrozoa: Sertulariidae) and its modified tentacles

2008 ◽  
Vol 88 (8) ◽  
pp. 1723-1729 ◽  
Author(s):  
Nicole Gravier-Bonnet
Keyword(s):  
Bilateral Symmetry ◽  
Accurate Description ◽  
General Shape ◽  
Median Part ◽  
First Time ◽  
Species Taxonomy

Study of living colonies of Salacia tetracythara Lamouroux, 1816, led to an accurate description of the hydranths and adjoining tissues. A mantle is reported for the first time for this species, lining stem, hydrocladia and hydrotheca. An adcauline nematocyst clump located in the median part of the column, composed of large microbasic mastigophores, is also reported as a new structure for sertulariids. The hypothetical modified tentacles noted by Billard (1925) are confirmed and re-described. Among the 22–28 tentacles of the hydranth in a circlet, two exhibit nematocyst-bearing organs connected at base. These organs are massive, racket-shaped, refringent, and composed of large microbasic mastigophores. They do not affect the tentacles in respect of their general shape and behaviour. One nematocyst-bearing organ can sometimes be linked to more than one tentacle depending on its size. The abcauline position of the two modified tentacles imparts a strong bilateral symmetry to the hydranth. This location explains why only one modified tentacle was previously described from preserved material, the second being hidden by the first when hydranths are retracted inside the hydrotheca. The modified tentacles of S. tetracythara are compared with the nematodactyls of the genus Nemalecium, with the ligula found in several sertulariid species, and with nematophores described in other thecate families. Beside remarks on species taxonomy and distribution, incitation is given to the study, with emphasis especially on hydranths.

Some poorly known Asterocheres species (Siphonostomatoida: Asterocheridae) deposited in the Natural History Museum of London

2008 ◽  
Vol 89 (3) ◽  
pp. 521-533 ◽  
Author(s):  
Eugenia Bandera ◽  
Conradi Mercedes
Keyword(s):  
Natural History ◽  
The Body ◽  
Natural History Museum ◽  
General Shape ◽  
History Museum ◽  
The Family ◽  
Mandibular Palp ◽  
First Time

A total of seven poorly known species of the genus Asterocheres, the largest genus of the family Asterocheridae, are redescribed based on material deposited in the Natural History Museum of London. Among the material available, there were specimens of both sexes of A. bulbosus, A. ellisi and A. rotundus; the dissected holotypes for A. hongkongensis, A. indicus and A. ovalis which have no other specimens; and only cotype of A. micheli, turned out to be lost. Some taxonomically important appendages of these species are described and illustrated for the first time. Furthermore, discrepancies have been observed in: (1) the general shape of the body; (2) the antennule segmentation; (3) the omission of some elements in various oral appendages; and (4) the segmentation of the mandibular palp. These redescribed species were then compared with their closest congeners.

scholarly journals Bashkir Theme in Works by P.L. Yudin, Orenburg Local Historian of the Beginning of the XX Century

2020 ◽  
pp. 27-30
Author(s):  
Viktoriya Yurevna Prokofeva ◽  
Alla Georgievna Prokofeva
Keyword(s):  
Scientific Activity ◽  
Historical Science ◽  
Early 19Th Century ◽  
Culture History ◽  
Historical Figures ◽  
Mode Of Life ◽  
Military Campaigns ◽  
Historical Past ◽  
First Time ◽  
Research Analysis

The article presents data on the studies by P.L. Yudin, a Russian historian-archivist of the beginning of the 20th century, local historian, a member of several scholarly archival commissions, who being a native of the Orenburg Region, dedicated his scientific activity to the study of multinational South Ural. For the first time, the Bashkir theme – research about the culture, history and people of Bashkiria – stands out in the scientist's legacy. Methods of research: analysis of the works of the scientist about Bashkir history, its culture and people, published in the magazines, newspapers. Based on the analysis of scientist’s works the following aspects of the study of Bashkiria by P.L. Yudin are distinguished: the historical past of the region – the settlement of Bashkir lands, a description of the Bashkir cities, the lives and mode of life of their inhabitants, archival data on the participation of the Bashkirs in the Pugachev uprising, the personality of V.A. Perovsky, Orenburg military governor general of the early 19th century, his military campaigns and citations about him in Bashkir history, historical visits to the Ufa Governorate by historical figures, including Emperor Alexander I, preparation for such visits, religious beliefs of the Bashkir population. Conclusion. The importance of studies by P.L. Yudin and the relevance of his archival finds for ethnography, ethnology and modern historical science is denoted as well.

Macrophthalmus aquensis A. Milne- Edwards et Brocchi 1879, son stade megalope; le genre Macrophthalmus Latreille 1829

1952 ◽  
Vol S6-II (1-3) ◽  
pp. 27-39
Author(s):  
Jean Marcel Remy
Keyword(s):  
Geographic Distribution ◽  
Mode Of Life ◽  
And Migration ◽  
First Time

Abstract On the basis of material from Vindobonian (Tertiary) marls of Perrin mountain near Aix-en-Provence, France, describes in detail and illustrates for the first time the Miocene crab Macrophthalmus aquensis (first noted by A. Milne-Edwards and Brocchi in 1879), including the megalope stage. The entire genus is reviewed with respect to its preservation, mode of life, stratigraphic and geographic distribution, and migration.

Mandalacystis, a new rhipidocystid eocrinoid from the Whiterockian Stage (Ordovician) in Oklahoma and Nevada

1987 ◽  
Vol 61 (6) ◽  
pp. 1222-1235 ◽  
Author(s):  
Ronald D. Lewis ◽  
James Sprinkle ◽  
J. Bowman Bailey ◽  
John Moffit ◽  
Ronald L. Parsley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Shallow Water ◽  
Plate Thickness ◽  
South Central ◽  
Mode Of Life ◽  
Thecal Plate ◽  
Juvenile Stages ◽  
First Time ◽  
Scanning Electron

Mandalacystis dockeryi n. gen. and sp. is known from seven complete or nearly complete thecae, six partial thecae, and numerous separate plates from the Oil Creek Formation in south-central Oklahoma, and a single thecal plate from the Antelope Valley Limestone in Nevada. Details of skeletal microstructure (stereom) are well preserved, permitting scanning electron microscopy for the first time in the Eocrinoidea, and demonstrating that plate thickness on thecal faces is only 60–70 μm. Mandalacystis is characterized by labyrinthine ridges on both faces of the theca, relatively short brachioles, and a normal stem with holdfast (at least in juvenile stages). Based on the normal biserial arrangement of brachiolar plates in the brachioles and the possession of a normal stem, Mandalacystis appears to be one of the most primitive rhipidocystids, closely related to Petalocystites.Mandalacystis dockeryi lived in a storm-dominated, shallow-water offshore habitat on patches of skeletal debris surrounded by soft, terrigenous mud. This setting may have been conducive to the transition from an erect, attached mode of life to the prone, unattached lifestyle of later rhipidocystids.

scholarly journals Notes on the Foraminiferal Genera <i>Laterostomella</i> De Klasz and Rérat and <i>Streptochilus</i> Brönnimann and Resig

1989 ◽  
Vol 8 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Ivan De Klasz ◽  
Dick Kroon ◽  
Jan E. Van Hinte
Keyword(s):  
North Atlantic ◽  
Morphological Variability ◽  
Isotopic Data ◽  
General Shape ◽  
The North ◽  
The Pacific ◽  
Upper Cenozoic ◽  
The Indian Ocean ◽  
The North Atlantic ◽  
First Time

Abstract. the biserial foraminiferal genera Laterostomella de Klasz &amp; Rérat (1962) and Streptochilus Brönnimann &amp; Resig (1971) have been described from the Miocene of Gabon and from Miocene to Recent levels of the Pacific and Indian Oceans, respectively. Both genera have since been found in the Upper Cenozoic of other regions: Laterostomella at Rockall Bank in the North Atlantic and in Papua-New-Guinea, and modern Streptochilus specimens were collected with plankton nets in the northern part of the Indian Ocean. The apertural characteristics of Laterostomella and Streptochilus show marked similarities as does the general shape of Laterostomella guembeliniformis with some Streptochilus species. However, other Laterostomella species have a very different form and isotopic data indicate that Laterostomella has a benthic and Streptochilus a planktic life habitat. We conclude that both genera are valid. For the first time SEM pictures of Laterostomella species are presented to show morphological variability, surface texture and aperture types.

scholarly journals Genesis and Morphotectonic Characterisation of Crescent- Shaped feature from Alcock Rise, Andaman Sea

2019 ◽  
Vol 34 (2) ◽  
Author(s):  
Sachin Kumar Tripathi ◽  
Resmi Sathikumar ◽  
Jishnu Balagangadharan Kaustubhakumari ◽  
Priyanka Dey Guha ◽  
Soibam Ishwarchandra Meitei
Keyword(s):  
Seismic Data ◽  
Normal Fault ◽  
Axial Ratio ◽  
Andaman Sea ◽  
Bottom Current ◽  
Width Ratio ◽  
Transform Fault ◽  
General Shape ◽  
Swath Bathymetry ◽  
First Time

Study of 98 crescent shape depressions over Alcock Rise, Andaman Sea were reported for the first time in between water depth -500 and -2000 m using multibeam swath bathymetry data. These gigantic depressions have crescent length (CL) varies from 600 to 3800 m and width (CW) varies from 200 to 2500 m with an average central depression of 500 m. Detailed parametric characterization reveals that slope and axial ratio of these crescentic structures have no direct relationship with general shape and steepness of their escarpment. Moreover, spatial distribution of these structures show a clustering of elongated crescent with higher crescent length to width ratio in NW margin of Alcock Rise compare to centre. This change in shape from open elliptical to semicircular depression probably suggests that earlier formed open crescents were modified at later stage to semicircular depressions. As observed in the seismic data, the formation of the crescentic depressions were initiated by the normal fault in-association with major dextral transform fault and subsequently its geometry was modified by local transpression along with seismicity induced slumping and bottom current scouring from the weaker zones. So, tectonics and bottom current activity provides simpler explanation for the formation of crescentic structure over Alcock Rise.Keywords: Crescentic depression, Alcock Rise, Swath bathymetry, Bottom current, Normal fault.

scholarly journals Reconstructing the ecology of a Jurassic pseudoplanktonic megaraft colony

2019 ◽  
Author(s):  
Aaron W. Hunter ◽  
David Casenove ◽  
Emily G. Mitchell ◽  
Celia Mayers
Keyword(s):  
Moisture Diffusion ◽  
Oceanic Islands ◽  
Diffusion Models ◽  
Deep Time ◽  
Cast Doubt ◽  
Commercial Logging ◽  
Mode Of Life ◽  
First Time

AbstractPseudoplanktonic crinoid megaraft colonies are an enigma of the Jurassic. They are among the largest in-situ invertebrate accumulations ever to exist in the Phanerozoic fossil record. These megaraft colonies and are thought to have developed as floating filter-feeding communities due to an exceptionally rich relatively predator free oceanic niche, high in the water column enabling them to reach high densities on these log rafts. However, this pseudoplanktonic hypothesis has never actually been quantitatively tested and some researchers have cast doubt that this mode of life was even possible. The ecological structure of the crinoid colony is resolved using spatial point process techniques and its longevity using moisture diffusion models. Using spatial analysis we found that the crinoids would have trailed preferentially positioned at the back of migrating structures in the regions of least resistance, consistent with a floating, not benthic ecology. Additionally, we found using a series of moisture diffusion models at different log densities and sizes that ecosystem collapse did not take place solely due to colonies becoming overladen as previously assumed. We have found that these crinoid colonies studied could have existed for greater than 10 years, even up to 20 years exceeding the life expectancy of modern documented megaraft systems with implications for the role of modern raft communities in the biotic colonisation of oceanic islands and intercontinental dispersal of marine and terrestrial species.Significance statementTransoceanic rafting is the principle mechanism for the biotic colonisation of oceanic island ecosystems. However, no historic records exist of how long such biotic systems lasted. Here, we use a deep-time example from the Early Jurassic to test the viability of these pseudoplanktonic systems, resolving for the first time whether these systems were truly free floating planktonic and viable for long enough to allow its inhabitants to grow to maturity. Using spatial methods we show that these colonies have a comparable structure to modern marine pesudoplankton on maritime structures, whilst the application of methods normally used in commercial logging is used to demonstrate the viability of the system which was capable of lasting up to 20 years.

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