Endobiotic cornulitids in Upper Ordovician tabulate corals and stromatoporoids from Anticosti Island, Quebec

2010 ◽  
Vol 84 (3) ◽  
pp. 518-528 ◽  
Author(s):  
Owen A. Dixon
Keyword(s):  
Coral Species ◽  
Coral Host ◽  
Shell Wall ◽  
Upper Ordovician ◽  
Layered Shell ◽  
Tabulate Coral ◽  
Anticosti Island ◽  
Commensal Relationship ◽  
Stratigraphic Range ◽  
Tabulate Corals

Conoidal shells of Cornulites celatus n. sp. occur commonly within host coralla of Propora conferta Milne-Edwards and Haime, 1851, sensu lato, from the Laframboise Member of the Ellis Bay Formation (Ashgill: Upper Ordovician) at Pointe Laframboise on western Anticosti Island. Examples have also been found at the same locality in the tabulate corals Paleofavosites sp., Acidolites arctatus Dixon, 1986, and A. compactus Dixon, 1986, and the stromatoporoid Ecclimadictyon sp., but not in other associated tabulate coral species. Growth interference between the shells and their hosts indicates a commensal relationship. C.celatus apparently had a more limited paleoenvironmental range than its principal coral host species, which occurs abundantly elsewhere on the island without its endobiotic partner. The diagnosis of Cornulites is emended to include forms having a two-layered shell wall with a distinctive outer layer consistently preserved as prismatic calcite. This new species extends the known stratigraphic range of cornulitids in commensal relationships with corals and stromatoporoids from the Silurian back to the Upper Ordovician.

Lamottia (Favositida, Tabulata) from the Decorah Formation (Kirkfieldian, Ordovician) of Iowa

1988 ◽  
Vol 62 (3) ◽  
pp. 424-426
Author(s):  
Jeffrey C. Edwards
Keyword(s):  
New York ◽  
Thin Section ◽  
Geographic Range ◽  
Upper Ordovician ◽  
North Central ◽  
The North ◽  
Tabulate Coral ◽  
Longitudinal Pattern ◽  
Stratigraphic Range ◽  
Diagenetic Feature

The early tabulate coral Lamottia heroensis has been identified from the Ion Member of the Decorah Formation (Upper Ordovician) in northeast Iowa. This extends the stratigraphic range of this species upward from Lower Chazyan to Kirkfieldian, and extends the geographic range from the Vermont-New York border area to include the north-central Midcontinent. Thin section and SEM studies strongly support the contention that the longitudinal pattern of alternating light and dark bands observed in corallite walls reflects a primary structural grain rather than a secondary diagenetic feature.

Katian (Late Ordovician) conodonts on the northwestern margin of the North China Craton

2021 ◽  
pp. 1-22
Author(s):  
Zhihua Yang ◽  
Xiuchun Jing ◽  
Hongrui Zhou ◽  
Xunlian Wang ◽  
Hui Ren ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Late Ordovician ◽  
Carbonate Platforms ◽  
Upper Ordovician ◽  
The North ◽  
Low Latitudes ◽  
Northwestern Margin ◽  
Conodont Fauna ◽  
Stratigraphic Range

Abstract Upper Ordovician strata exposed from the Baiyanhuashan section is the most representative Late Ordovician unit in the northwestern margin of the North China Craton (NCC). In total, 1,215 conodont specimens were obtained from 24 samples through the Wulanhudong and Baiyanhuashan formations at the Baiyanhuashan section. Thirty-six species belonging to 17 genera, including Tasmanognathus coronatus new species, are present. Based on this material, three conodont biozones—the Belodina confluens Biozone, the Yaoxianognathus neimengguensis Biozone, and the Yaoxianognathus yaoxianensis Biozone—have been documented, suggesting that the Baiyanhuashan conodont fauna has a stratigraphic range spanning the early to middle Katian. The Baiyanhuashan conodont fauna includes species both endemic to North China and widespread in tropical zones, allowing a reassessment of the previous correlations of the Katian conodont zonal successions proposed for North China with those established for shallow-water carbonate platforms at low latitudes. UUID: http://zoobank.org/7cedbd4a-4f7a-4be6-912f-a27fd041b586

scholarly journals Ocean acidification increases photosynthate translocation in a coral–dinoflagellates symbiosis

2013 ◽  
Vol 10 (1) ◽  
pp. 83-109 ◽  
Author(s):  
P. Tremblay ◽  
M. Fine ◽  
J. F. Maguer ◽  
R. Grover ◽  
C. Ferrier-Pagès
Keyword(s):  
Coral Species ◽  
Total Carbon ◽  
Coral Host ◽  
Climate Change Scenarios ◽  
Symbiotic Association ◽  
Stylophora Pistillata ◽  
Gross Photosynthesis ◽  
Total Percentage ◽  
Carbon Translocation ◽  
Tropical Coral

Abstract. This study has examined the effect of an increased seawater pCO2 on the rates of photosynthesis and carbon translocation in the scleractinian coral species Stylophora pistillata using a new model based on 13C-labelling of the photosynthetic products. Symbiont photosynthesis contributes for a large part of the carbon acquisition in tropical coral species and is therefore an important process that may determine their survival under climate change scenarios. Nubbins of S. pistillata were maintained for six months under two pHs (8.1 and 7.2). Rates of photosynthesis and respiration of the symbiotic association and of isolated symbionts were assessed at each pH. The fate of 13C-photosynthates was then followed in the symbionts and the coral host for 48 h. Nubbins maintained at pH 7.2 presented a lower areal symbiont concentration, lower areal rates of gross photosynthesis, and lower carbon incorporation rates compared to nubbins maintained at pH 8.1, therefore suggesting that the total carbon acquisition was lower in this first set of nubbins. However, the total percentage of carbon translocated to the host, as well as the amount of carbon translocated per symbiont cell was significantly higher under pH 7.2 than under pH 8.1 (70% at pH 7.2 versus 60% at pH 8.1), so that the total amount of photosynthetic carbon received by the coral host was equivalent under both pHs (5.5 to 6.1 μg C cm−2 h−1). Although the carbon budget of the host was unchanged, symbionts acquired less carbon for their own needs (0.6 against 1.8 μg C cm−2 h−1), explaining the overall decrease in symbiont concentration at low pH. In the long-term, this decrease might have important consequences for the survival of corals under an acidification stress.

Maturation thermique et histoire de l'enfouissement et de la génération des hydrocarbures du bassin de l'archipel de Mingan et de l'île d'Anticosti, Canada

1990 ◽  
Vol 27 (6) ◽  
pp. 731-741 ◽  
Author(s):  
Rudolf Bertrand
Keyword(s):  
Carbonate Platform ◽  
Burial History ◽  
Upper Ordovician ◽  
Southeastern Part ◽  
Middle Ordovician ◽  
Oil Generation ◽  
Wide Range ◽  
History Of ◽  
Anticosti Island ◽  
Depth Of Burial

Carbonate platform sequences of Anticosti Island and the Mingan Archipelago are Early Ordovician to Early Silurian in age. With the exception of the Macasty Formation, the sequences are impoverished in dispersed organic matter, which is chiefly composed of zooclasts. Zooclast reflectances suggest that the Upper Ordovician and Silurian sequences outcropping on Anticosti Island are entirely in the oil window but that the Lower to Middle Ordovician beds of the Mingan Archipelago and their stratigraphic equivalents in the subsurface of most of Anticosti Island belong to the condensate zone. Only the deeper sequences of the southwestern sector of Anticosti Island are in the diagenetic dry-gas zone. The maximum depth of burial of sequences below now-eroded Silurian to Devonian strata increases from 2.3 km on southwestern Anticosti Island to 4.5 km in the Mingan Archipelago. A late upwarp of the Precambrian basement likely allowed deeper erosion of the Paleozoic strata in the vicinity of the Mingan Archipelago than on Anticosti Island. Differential erosion resulted in a southwestern tilting of equal maturation surfaces. The Macasty Formation, the only source rock of the basin (total organic carbon generally > 3.5%, shows a wide range of thermal maturation levels (potential oil window to diagenetic dry gas). It can be inferred from the burial history of Anticosti Island sequences that oil generation began later but continued for a longer period of geologic time in the northeastern part than in the southeastern part of the island. Oil generation was entirely pre-Acadian in the southern and western parts of Anticosti Island, but pre- and post-Acadian in the northern and eastern parts.

Upper Ordovician ostracods from the Cautley district, northern England: Baltic and Laurentian affinities

2001 ◽  
Vol 138 (5) ◽  
pp. 589-607 ◽  
Author(s):  
MARK WILLIAMS ◽  
PHILIP STONE ◽  
DAVID J. SIVETER ◽  
PAULINE TAYLOR
Keyword(s):  
North America ◽  
Significant Extent ◽  
Baltic Region ◽  
Upper Ordovician ◽  
Northern Germany ◽  
Iapetus Ocean ◽  
Windermere Supergroup ◽  
Distributional Patterns ◽  
Anticosti Island ◽  
The Baltic

The Cautley Mudstone Formation and Cystoid Limestone Member of the Ashgill Formation (Windermere Supergroup; Ashgill Series), from the Cautley district of northern England, has yielded an ostracod fauna of more than 30 species. Many of these have short ranges, permitting recognition of stratigraphically successive Pusgillian–lower Cautleyan, middle–upper Cautleyan, and Rawtheyan ostracod faunas. Several species are also known from the upper Ordovician of North America (Anticosti Island), Scotland (Girvan district) and the Baltic region (Estonia, glacial erratic boulders of northern Germany), providing evidence to correlate upper Ordovician successions in these areas. The ostracods include abundant podocopes, at some horizons accounting for more than 80% of the fauna. Binodicopes are also common, but palaeocopes are rare. Assemblages are typical of a clastic dominated open marine shelf setting. Diversity at most horizons is low (c. 3–5 species), but reaches a peak of between 13–14 species in middle Cautleyan horizons. Lower diversity at Pusgillian and Rawtheyan horizons coincides with the encroachment of deeper marine-shelf facies which were probably hostile to Ordovician benthonic ostracods. Some of the ostracods (particularly Aechmina) have distributions suggesting tolerance of a range of mid- to deep shelf benthonic palaeoenvironments, but none were pelagic. During Ashgill times the Cautley district (part of palaeocontinental Avalonia) was replete with ostracod genera and species which also occur in the Baltic region (palaeocontinental Baltica; more than 90% generic similarity) and to a lesser, but nonetheless significant extent in North America and Scotland (parts of palaeocontinental Laurentia). Such trans-Tornquist Sea and Iapetus Ocean distributional patterns add to previous ostracod data that support models which show palaeogeographical proximity of Avalonia and Baltica, and Avalonia and Laurentia, by Ashgill times. The widely cited observation, that trans-Iapetus ostracod faunas remained strictly provincial until the mid-or late Silurian, cannot be sustained.

scholarly journals The mushroom coral as a habitat

2011 ◽  
Vol 92 (4) ◽  
pp. 647-663 ◽  
Author(s):  
Bert W. Hoeksema ◽  
Sancia E.T. Van der Meij ◽  
Charles H.J.M. Fransen
Keyword(s):  
Coral Species ◽  
Marine Biodiversity ◽  
Coral Host ◽  
Associated Fauna ◽  
Reef Corals ◽  
Symbiotic Relationships ◽  
Mushroom Coral ◽  
Endosymbiotic Algae ◽  
Associated Species ◽  
Shallow Seas

The evolution of symbiotic relationships involving reef corals has had much impact on tropical marine biodiversity. Because of their endosymbiotic algae (zooxanthellae) corals can grow fast in tropical shallow seas where they form reefs that supply food, substrate and shelter for other organisms. Many coral symbionts are host-specific, depending on particular coral species for their existence. Some of these animals have become popular objects for underwater photographers and aquarists, whereas others are hardly noticed or considered pests. Loss of a single coral host species also leads to the disappearance of some of its associated fauna. In the present study we show which mushroom corals (Scleractinia: Fungiidae) are known to act as hosts for other organisms, such as acoel flatworms, copepods, barnacles, gall crabs, pontoniine shrimps, mytilid bivalves, epitoniid snails, coralliophilid snails, fish and certain types of zooxanthellae. Several of these associated organisms appear to be host-specific whereas other species are generalists and not even necessarily restricted to fungiid hosts.Heliofungia actiniformisis one of the most hospitable coral species known with a recorded associated fauna consisting of at least 23 species. The availability of a phylogeny reconstruction of the Fungiidae enables comparisons of closely related species of mushroom corals regarding their associated fauna. Application of a phylogenetic ecological analysis indicates that the presence or absence of associated organisms is evolutionarily derived or habitat-induced. Some associations appear to be restricted to certain evolutionary lineages within the Fungiidae, whereas the absence of associated species may be determined by ecomorphological traits of the host corals, such as coral dimensions (coral diameter and thickness) and polyp shape (tentacle size).

scholarly journals Sedimentology and paleoecology of Upper Ordovician mounds of Anticosti Island, Quebec

1981 ◽  
Vol 18 (10) ◽  
pp. 1562-1571 ◽  
Author(s):  
John H. Lake
Keyword(s):  
Late Ordovician ◽  
Calcareous Algae ◽  
Upper Ordovician ◽  
Salmon River ◽  
Shallow Subtidal ◽  
Anticosti Island ◽  
Primary Porosity

Relatively thin organic buildups in the Ellis Bay Formation of Anticosti Island developed in a shallow subtidal regressive marine shelf environment during the Late Ordovician. The Ellis Bay Formation has been subdivided into six members by Bolton. Two buildups, one in each of members 4 and 6, were studied in detail. The member 6 mud mound on the Salmon River (8 m thick) is bound by calcareous algae, stromatoporoids, and corals, and consists of a micritic bafflestone core capped by crinoidal lime grainstone. Early marine cementation permeated nearly all of the primary porosity. Cathodoluminescence indicates at least five stages of cementation of the mound. Constructive mound development was terminated by progressively shallowing, agitated marine conditions.The member 4 mound is a small coral (ecological) reef exposed on the Vaureal River.

Stratigraphy of the Upper Ordovician upper Vaureal and Ellis Bay formations, eastern Anticosti Island, Quebec

1987 ◽  
Vol 24 (9) ◽  
pp. 1807-1820 ◽  
Author(s):  
D. G. F. Long ◽  
Paul Copper
Keyword(s):  
Late Ordovician ◽  
Eastern Coast ◽  
Upper Ordovician ◽  
New Members ◽  
Patch Reefs ◽  
Accurate Definition ◽  
Central Regions ◽  
Shallow Subtidal ◽  
Anticosti Island ◽  
Definition Of

Marked facies changes occur in Late Ordovician strata, assigned to the uppermost Vaureal and Ellis Bay formations (Ashgill: Rawtheyan–Hirnantian) on Anticosti Island, Quebec. Western Anticosti features shales and carbonates, whereas outcrops along the eastern coast contain prominent, discontinuous, mixed siliciclastic–carbonate units. Detailed section measurement along the northeast coast allows, for the first time, accurate definition of seven new members within this uninterrupted sequence. Sands present in the upper Vaureal and lower Ellis Bay formations in the east appear to have deterred the growth of muddy-bottom brachiopod communities comparable to those in the western and central regions of Anticosti. Sand units within the upper Vaureal Formation contain 1 m diameter colonies of Paleofavosites; coeval small coral patch reefs are found in the central part of the island, where sands are absent. The uppermost Ellis Bay Formation of northeast Anticosti is marked by a shallow, subtidal, coral–algal oncolite bed or by small (2–4 m across, 1–2 m thick) local coral patch reefs, the tops of which have been used to define the Ordovician – Silurian boundary. No supratidal or intertidal sediments and faunas are evident in the Anticosti succession, suggesting that Late Ordovician sea-level drawdown was insufficient to provide shelf-emergent conditions in this region.

Les chitinozoaires de la zone à Climacograptus prominens elongatus de la Formation de Vauréal (Ordovicien supérieur), Ile d'Anticosti, Québec

1977 ◽  
Vol 14 (10) ◽  
pp. 2193-2212 ◽  
Author(s):  
A. Achab
Keyword(s):  
New Species ◽  
Upper Ordovician ◽  
Anticosti Island

The aim of this paper is to describe the chitinozoans from the Climacograptus prominens elongatus Zone from the upper part of the Vaureal Formation (Upper Ordovician) of Anticosti Island. An emendation of the genus Hercochitina is proposed. Seven new species, Hercochitina normalis, H. minuta, H. filamentosa, H. grandispina, Conochitina baculata, C. armifera, and Ancyrochitina spongiosa are described.The microfauna characterized by the dominance of Hercochitina, is distinctive and does not resemble those reported from elsewhere.

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