scholarly journals Palaeogeographic implications of a new iocrinid crinoid (Disparida) from the Ordovician (Darriwillian) of Morocco

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1450 ◽  
Author(s):  
Samuel Zamora ◽  
Imran A. Rahman ◽  
William I. Ausich

Complete, articulated crinoids from the Ordovician peri-Gondwanan margin are rare. Here, we describe a new species,Iocrinus africanussp. nov., from the Darriwilian-age Taddrist Formation of Morocco. The anatomy of this species was studied using a combination of traditional palaeontological methods and non-destructive X-ray micro-tomography (micro-CT). This revealed critical features of the column, distal arms, and aboral cup, which were hidden in the surrounding rock and would have been inaccessible without the application of micro-CT.Iocrinus africanussp. nov. is characterized by the presence of seven to thirteen tertibrachials, three in-line bifurcations per ray, and an anal sac that is predominantly unplated or very lightly plated.Iocrinusis a common genus in North America (Laurentia) and has also been reported from the United Kingdom (Avalonia) and Oman (middle east Gondwana). Together withMerocrinus, it represents one of the few geographically widespread crinoids during the Ordovician and serves to demonstrate that faunal exchanges between Laurentia and Gondwana occurred at this time. This study highlights the advantages of using both conventional and cutting-edge techniques (such as micro-CT) to describe the morphology of new fossil specimens.

Zootaxa ◽  
2011 ◽  
Vol 2742 (1) ◽  
pp. 60 ◽  
Author(s):  
DAVID PENNEY ◽  
ANDREW MCNEIL ◽  
DAVID I. GREEN ◽  
ROBERT BRADLEY ◽  
YURI M. MARUSIK ◽  
...  

A new species of the extant spider family Anapidae is described from a fossil mature male in Eocene amber from the Baltic region and tentatively assigned to the genus Balticoroma Wunderlich, 2004. Phase contrast X-ray computed micro-tomography was used to reveal important features that were impossible to view using traditional microscopy. Balticoroma wheateri new species is easily diagnosed from all other anapids by having clypeal extensions that run parallel to the ectal surface of the chelicerae and in having the metatarsus of the first leg highly reduced and modified into what is presumably a y-shaped clasping structure. Although only a single extant anapid species occurs in northern Europe, the family was diverse in the Eocene. The discovery of yet another anapid species in Baltic amber supports the idea that Eocene European forests may have been a hotspot of evolution for this family of spiders.


Zootaxa ◽  
2017 ◽  
Vol 4318 (1) ◽  
pp. 110
Author(s):  
JOACHIM SCHMIDT ◽  
TORBEN GÖPEL ◽  
KIPLING WILL

Species of the megadiverse ground beetle tribe Platynini occur on all continents except Antarctica. It has been long recognized that platynine beetles were preserved in the Eocene Baltic amber. However, thus far only a single Eocene fossil has been described to the species level. In the present paper, a new species of Platynini known only as an amber inclusion fossil is described and imaged using light microscopy and micro X-ray computed tomography. Since this species cannot be assigned to any of the recently described genera, the monotypic genus Praeanchodemus gen. n., with the type species P. punctaticeps sp. n., is erected. There is some evidence from external morphology that Praeanchodemus gen. n. is part of a lineage comprising the recent genera Paranchodemus, Rhadine, and Tanystoma. However, since some synapomorphies were not found, the true relationships of the fossil taxon remain moot. 


2010 ◽  
pp. 109-117 ◽  
Author(s):  
Neda Motchurova-Dekova ◽  
David Harper

Synchrotron radiation X-ray tomographic microscopy (SRXTM) is a non-destructive technique for the investigation and visualization of the internal features of solid opaque objects, which allows reconstruction of a complete three-dimensional image of internal structures by recording of the differences in the effects on the passage of waves of energy reacting with those structures. Contrary to X-rays, produced in a conventional X-ray tube, the intense synchrotron light beams are sharply focused like a laser beam. We report encouraging results from the use of SRXTM for purely taxonomic purposes in brachiopods: an attempt to find a non-destructive and more efficient alternative to serial sectioning and several other methods of dissection together with the non-destructive method of X-ray computerised micro-tomography. Two brachiopod samples were investigated using SRXTM. In ?Rhynchonella? flustracea it was possible to visualise the 3D shape of the crura and dental plates. In Terebratulina imbricata it was possible to reveal the form of the brachidium. It is encouraging that we have obtained such promising results using SRXTM with our very first two fortuitous samples, which had respectively fine-grained limestone and marl as infilling sediment, in contrast to the discouraging results communicated to us by some colleagues who have tested specimens with such infillings using X-ray micro-tomography. In future the holotypes, rare museum specimens or delicate Recent material may be preferentially subjected to this mode of analysis.


2016 ◽  
Vol 45 (5) ◽  
pp. 566-578 ◽  
Author(s):  
Fernando Carbayo ◽  
Tiago M. Francoy ◽  
Gonzalo Giribet

2008 ◽  
Vol 72 (5) ◽  
pp. 1071-1082 ◽  
Author(s):  
G. Raade ◽  
J. D. Grice ◽  
M. Erambert ◽  
P. Kristiansson ◽  
T. Witzke

AbstractA REE-bearing fluorosilicate from the Tommot REE-Nb deposit in Yakutia, Russia, described without a name in 1966, is characterized here as a new species, proshchenkoite-(Y), of the vicanite group of borosilicates. Wavelength-dispersive electron probe analyses gave the following empirical formula: Y3.70REE7.54Ca1.55Na1.16Mn0.77Th0.10Pb0.01)Σ14.83(Fe2+0.83Mn0.15Ti0.02)Σ1.00Ca1.00(P0.70Si0.26As0.04)Σ1.00Si0.26B3.20(O34.55F13.45)Σ48. Boron was analysed with a nuclear microprobe method based on the nuclear reaction 11B(p,α)2α. The simplified formula is (Y,REE,Ca,Mn)15(Fe2+,Mn)Ca(P,Si)Si6B3O34F14. The mineral is trigonal, R3m, with a = 10.7527(7) Å, c = 27.4002(18) Å, V = 2743.6(6) Å 3, Z = 3. The crystal structure was refined to Rl = 0.042 for 1819 observed reflections. Proshchenkoite-(Y) is isostructural with okanoganite-(Y), vicanite-(Ce) and hundholmenite-(Y), and the differences in site occupancies are discussed. The strongest six reflections of the X-ray powder-diffraction pattern [dobs in Å, (I), (hkl)] are: 4.441, (36), (202); 3.144, (77), (214); 3.028, (45). (009); 2.968, (100), (027); 1.782, (32), (330); and 1.713, (32), (1.2.14). The mineral is optically uniaxial (—) with ω 1.734(2) and 8 1.728(2). The Mohs hardness is about 5; density measured on material subject to incipient metamictization is 4.72 g/cm3, as compared to Dcalc = 4.955 g/cm3.The result of electron microprobe analyses of alleged okanoganite-(Y) from the type locality in Okanogan County, Washington, USA, is also presented. We find here also that P > Si at one of the sites, whereas the analytical data of Boiocchi et al. (2004) indicate Si > P. Consequently, the mineral we have analysed is the P analogue of okanoganite-(Y), another new species.


1983 ◽  
Vol 47 (344) ◽  
pp. 387-389 ◽  
Author(s):  
Pete J. Dunn ◽  
Peter B. Leavens

AbstractBostwickite, CaMn63+Si3O16-7H2O, is a new species from the Franklin Mine, Franklin, New Jersey. Chemical analysis yielded MgO 0.9, CaO 5.1, Mn2O3 56.3, Fe2O3 0.5, Al2O3 1.0, As2O5 1.0, SiO2 20.1, H2O [15.1], sum = 100.0%. This yields (Ca0.76Mg0.19)Σ0.95(Mn5.973+Fe0.053+)Σ6.02(Si2.80Al0.16As0.075+)Σ6.02(Si2.80Al0.16AS5+0.07)Σ3.03O16·7.01H2O, corresponding to the idealized formula. The strongest lines in the X-ray powder diffraction pattern are (d, I): 11.3, 100; 3.548, 30; 2.898, 30; 2.567, 40; 2.262, 25; 2.238, 25; 1.470, 25. Bostwickite is dark red in colour; hardness c. 1 (Mohs'); density (meas.)= 2.93 g/cm3. It occurs in radial aggregates of acicular compound crystals. Optically, bostwickite is biaxial negative with 2Vα = 25deg; α = 1.775, Β = 1.798, γ = 1.800;, dispersion strong, r > v; strongly pleochroic with α = β redbrown, γ = yellow-brown; absorption is α = β = γ. Bostwickite is named in honour of Richard C. Bostwick, collector and compiler of data on the minerals of Franklin and Sterling Hill.


Zootaxa ◽  
2011 ◽  
Vol 3085 (1) ◽  
pp. 63
Author(s):  
DANIEL R. L. PYE

A new vagrant eriophyoid mite species, collected from plant material imported into the United Kingdom, is described and illustrated: Aceria argentae n. sp. found on Leucadendron argenteum (L.) R. Br. (Proteaceae) from South Africa. A review of the eriophyoid mite species known from plants in the Proteaceae is also provided and recent findings of non-native eriophyoid mites in the United Kingdom are discussed.


2007 ◽  
Vol 87 (6) ◽  
pp. 1485-1490 ◽  
Author(s):  
Pilar Ríos ◽  
Javier Cristobo

Phorbas is a common genus with cosmopolitan distribution. A new species of sponge, Phorbas megasigma sp. nov. (Porifera: Poecilosclerida: Hymedesmiidae) is described from material collected during the third Spanish expedition on the study of the Antarctic benthos, ‘Bentart 03’. Phorbas megasigma is closely related to P. nexus but differs in the possession of arcuate chelae and very big sigmata as microscleres.


2013 ◽  
Vol 21 (2) ◽  
pp. 24-28 ◽  
Author(s):  
Bart Pauwels ◽  
Alexander Sasov

X-ray microfocus computer tomography (μ-CT) is a non-destructive experimental technique that reveals the 3D internal microstructure of the sample under study. The experimental set-up consists of an X-ray source, an X-ray detector, and set in between is a sample that is placed on a rotation stage. With this set-up multiple X-ray projection images can be obtained from the sample at different angles. In between the acquisition of two successive images, the sample is rotated over a small angle, typically between 0.2° and 1°. This set of projection images is then used as input for the reconstruction algorithm, which calculates a reconstruction of the internal microstructure of the sample with (sub-) micrometer sensitivity.


Biologia ◽  
2010 ◽  
Vol 65 (1) ◽  
Author(s):  
Petr Hašler ◽  
Aloisie Poulíčková

AbstractEpipelic cyanobacteria were studied in bottom sediments from ponds and lakes in the United Kingdom and the Czech Republic, covering a trophic gradient from deep, oligotrophic, glacial lakes to shallow, eutrophic, urban manmade ponds. Although many planktic species were observed, the most frequently occurring cyanobacteria were the motile filamentous genera Oscillatoria, Phormidium, Pseudanabaena and Komvophoron. These genera represent autochtonous epipelic assemblages, occurring in upper surface layers of the sediments throughout the year and exhibiting seasonal variation in their abundancy. The occurrence of individual Komvophoron species was influenced by sediment quality, particularly the proportions of fine mud and organic detritus. A new species Komvophoron hindakii sp. nov. is described. Morphological features, autecology and occurrence of all the Komvophoron-like morphospecies found are discussed.


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