Middle Ordovician Fish-bearing Beds from the St. Lawrence Lowlands of Quebec

1973 ◽  
Vol 10 (6) ◽  
pp. 954-960 ◽  
Author(s):  
Leslie S. Eliuk

Ostracoderm tubercles were recovered from the lower portion of two Black River Group sections between Montreal and Quebec City. Some of these fish remains seem identical to tubercles of Astraspis desiderata from the Harding Sandstone of Colorado. The age of the Quebec remains is questionably earliest Blackriveran or basal Caradocian of the European standard. The remains were found in sandy carbonates probably laid down in the supratidal to shallow marine environments. It is concluded that these remains may represent part of a continent-wide, biostratigraphically useful vertebrate fauna and that bulk sampling and acid residuing might be a technique whereby sparse, fragmentary, earliest Paleozoic fish remains could be found.

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5594 ◽  
Author(s):  
Agustín G. Martinelli ◽  
Thiago S. Marinho ◽  
Fabiano V. Iori ◽  
Luiz Carlos B. Ribeiro

Field work conducted by the staff of the Centro de Pesquisas Paleontológicas Llewellyn Ivor Price of the Universidade Federal do Triângulo Mineiro since 2009 at Campina Verde municipality (MG) have resulted in the discovery of a diverse vertebrate fauna from the Adamantina Formation (Bauru Basin). The baurusuchidCampinasuchus diniziwas described in 2011 from Fazenda Três Antas site and after that, preliminary descriptions of a partial crocodyliform egg, abelisaurid teeth, and fish remains have been done. Recently, the fossil sample has been considerably increased including the discovery of several, partially articulated fish remains referred to Lepisosteiformes and an almost complete and articulated skeleton referred to a new species ofCaipirasuchus(Notosuchia, Sphagesauridae), which is the main subject of this contribution. At present, this genus was restricted to the Adamantina Formation cropping out in São Paulo state, with the speciesCaipirasuchus montealtensis,Caipirasuchus paulistanus, andCaipirasuchus stenognathus. The new material represents the holotype of a new species,Caipirasuchus mineirusn. sp., diferenciated from the previously ones due to the following traits: last two maxillary teeth located posterior to anterior edge of infraorbital fenestra, elongated lateroventral maxillo-jugal suture—about ½ the anteroposterior maxillar length—and contact between posterior crest of quadrate and posterior end of squamosal forming an almost 90° flaring roof of the squamosal, among others.C. mineiruswas found in the same outcrop thanCampinasuchusbut stratigraphically the former occurs in the lower portion of the section with no unambiguous data supporting the coexistance of both taxa.


1983 ◽  
Vol 7 ◽  
pp. 167-172
Author(s):  
Carl W. Stock

The great majority of the published work on the paleontology of the stromatoporoids has appeared since 1950. This influx of information has made possible a fairly clear picture of their evolution. As mentioned earlier by Stearn, stromatoporoids were quite abundant in shallow marine environments from the Middle Ordovician through the Late Devonian. These are referred to as the “Paleozoic stromatoporoids.” The record of Carboniferous stromatoporoids is sparse, but they began to come back in the Permian, and were common again through much of the Mesozoic, until disappearing at the the end of the Cretaceous. The Permian through Cretaceous forms shall be referred to as the “Mesozoic stromatoporoids.”


2003 ◽  
Vol 48 (1part2) ◽  
pp. 535-546 ◽  
Author(s):  
F. Carol Stephens ◽  
Eric M. Louchard ◽  
R. Pamela Reid ◽  
Robert A. Maffione

2018 ◽  
Author(s):  
Saira Bannu Baharuddin ◽  
Hani Abul Khair ◽  
Reza Amarullah Bekti ◽  
Amita Mohd Ali ◽  
Budi Kantaatmadja ◽  
...  

2021 ◽  
pp. 1-18
Author(s):  
Dong-Jin Lee ◽  
Robert J. Elias ◽  
Brian R. Pratt

Abstract Modular coral-like fossils from Lower Ordovician (Tremadocian) thrombolitic mounds in the St. George Group of western Newfoundland were initially identified as Lichenaria and thought to include the earliest tabulate corals. They are here assigned to Amsassia terranovensis n. sp. and Amsassia? sp. A from the Watts Bight Formation, and A. diversa n. sp. and Amsassia? sp. B from the overlying Boat Harbour Formation. Amsassia terranovensis n. sp. and A. argentina from the Argentine Precordillera are the earliest representatives of the genus. Amsassia is considered to be a calcareous alga, possibly representing an extinct group of green algae. The genus originated and began to disperse in the Tremadocian, during the onset of the Great Ordovician Biodiversification Event, on the southern margin of Laurentia and the Cuyania Terrane. It inhabited small, shallow-marine reefal mounds constructed in association with microbes. The paleogeographic range of Amsassia expanded in the Middle Ordovician (Darriwilian) to include the Sino-Korean Block, as well as Laurentia, and its environmental range expanded to include non-reefal, open- and restricted-marine settings. Amsassia attained its greatest diversity and paleogeographic extent in the Late Ordovician (Sandbian–Katian), during the culmination of the Great Ordovician Biodiversification Event. Its range included the South China Block, Tarim Block, Kazakhstan, and Siberia, as well as the Sino-Korean Block and Laurentia, and its affinity for small microbial mounds continued during that time. In the latest Ordovician (Hirnantian), the diversity of Amsassia was reduced, its distribution was restricted to non-reefal environments in South China, and it finally disappeared during the end-Ordovician mass extinction. UUID: http://zoobank.org/ef0abb69-10a6-46de-8c78-d6ec7de185fe


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