Pelagic Amphipoda of the Belle Isle Strait Region

1951 ◽  
Vol 8b (3) ◽  
pp. 134-163 ◽  
Author(s):  
E. L. Bousfield
Keyword(s):  
Light Intensity ◽  
Breeding Season ◽  
Cold Water ◽  
Ocean Currents ◽  
Southern Limit ◽  
Index Species ◽  
Labrador Current ◽  
Themisto Libellula

The distribution of certain pelagic Amphipoda taken in the Belle Isle strait region during the summer of 1923 is correlated with ocean currents, light intensity and size of individuals. Hyperoche medusarum, Themisto libellula and Pseudalibrotus glacialis are index species of the cold Labrador current in the area. Hyperia galba and H. medusarum are presumably also cold water indicators. Themisto abyssorum in sizeable numbers, and Calliopius laeviusculus are related to waters of the gulf of St. Lawrence. Themisto libellula, T. compressa form compressa and T. compressa form bispinosa are more numerous, while T. abyssorum is less numerous at the surface during daylight than during darkness. Part of the breeding season of T. compressa and T. abyssorum occurs in the area during August and September, when the young of both species are much more numerous than the adults, particularly at the surface. A new southern limit of distribution for P. glacialis is established. The known distribution of the tropical genus Phronima is extended into the gulf of St. Lawrence.

scholarly journals Upper Tithonian ammonites (Himalayitidae Spath, 1925 and Neocomitidae Salfeld, 1921) from Charens (Drôme, France)

2016 ◽  
Vol 67 (6) ◽  
pp. 543-559 ◽  
Author(s):  
Camille Frau ◽  
Luc G. Bulot ◽  
William A.P. Wimbledon ◽  
Christina Ifrim
Keyword(s):  
Species Distribution ◽  
Lower Boundary ◽  
Biometric Analysis ◽  
Faunal Assemblages ◽  
Index Species ◽  
Vertical Range ◽  
Spanish Populations ◽  
Range Of Variation

AbstractThis contribution focuses on the Perisphinctoidea ammonite taxa from the Upper Tithonian at Charens (Drôme, south-east France). Emphasis is laid on five genera that belong to the families Himalayitidae and Neocomitidae. We document the precise vertical range of the index-species Micracanthoceras microcanthum, and a comparative ontogenetic- biometric analysis sheds new light on its range of variation and dimorphism as compared to the bestknown Spanish populations. As herein understood, the lower boundary of the M. microcanthum Zone (base of the Upper Tithonian) is fixed at the FAD of its index species. The faunal assemblages and species distribution of the P. andreaei Zone are rather similar to those described at the key-section of Le Chouet as confirmed by the co-occurrence of the genera Protacanthodiscus, Boughdiriella and Pratumidiscus. New palaeontological evidence supports the view that the basal Neocomitidae Busnardoiceras busnardoi was derived from Protacanthodiscus andreaei in the upper part of the P. andreaei Zone.

Photopolymerizable glass with high refractive index species: Overview of emerging implementations

2009 ◽  
Author(s):  
Maria L. Calvo ◽  
Oscar Martinez-Matos ◽  
Jose A. Rodrigo ◽  
Tatiana Alieva ◽  
Maria Paz Hernandez-Garay ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Refractive Index ◽  
Index Species

scholarly journals The First Appearance Datum (FAD) of <i>Heterosphaeridium difficile</i> (Manum & Cookson), dinoflagellata, in clastic deposits offshore Norway

1997 ◽  
Vol 16 (1) ◽  
pp. 30-30 ◽  
Author(s):  
D. G. Bell ◽  
H. Selnes
Keyword(s):  
Late Cretaceous ◽  
Good Control ◽  
Detailed Account ◽  
Core Samples ◽  
Index Species ◽  
Important Correlation ◽  
North Norway

Abstract. INTRODUCTIONThick sequences of clastic deposits of Late Cretaceous age (1000–1500 m) are present offshore mid and north Norway. Dinoflagellate assemblages from these deposits have arctic affinities and are dominated by species of Chatangiella, Trithyrodinium and Isabelidinium. The First Appearance Datum (FAD) of Heterosphaeridium difficile is an important correlation point within this sequence and is equated with a Turonian age in most current zonal schemes. Our observations on the relative ranges of H. difficile, members of the Endoceratium dettmanniae–E. ludbrookiae plexus and other key index species in well materials offshore mid and north Norway are not consistent with ranges documented from European stratotypes and suggest a Cenomanian age for the correlation point. This note is intended as a basis for discussion pending a more detailed account of these deposits.OBSERVATIONSThree released offshore wells with good control from sidewall and core samples were selected for study. All of the well sections produced rich typical middle Cretaceous dinocyst assemblages with common H. difficile. At some levels typical forms of H. difficile with discrete processes intergrade with morphotypes having shorter, wider, coalescing processes, probably related to species in the Cyclonephelium membraniphorum complex. As recognized here, H. difficile is restricted to forms similar to the holotype, with discrete processes. Species of Endoceratium are present consistently in the lower part of the H. difficile range zone. There is gradation between forms close to E. dettmanniae and E. ludbrookiae to reticulate forms similar to E. lurneri.Well 35/3–5 is located about 190 km . . .

Ordovician chitinozoan zonation of Quebec and western Newfoundland

1989 ◽  
Vol 63 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Aicha Achab
Keyword(s):  
Great Britain ◽  
North America ◽  
Index Species

The purpose of this paper is to propose a chitinozoan zonation of the Ordovician of Quebec and western Newfoundland. On the basis of chitinozoan assemblages previously described from various sections, covering almost the entire Ordovician System, 22 biozones, based on first appearance of index species, are distinguished. As the strata from which the chitinozoan microfaunas were extracted are well dated by other fossils, especially graptolites, it is possible to establish a correlation between the chitinozoan and the established graptolite and conodont zonations of North America and Great Britain.

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