摘要:

What can distinguish ecostratigraphy from other stratigraphic concepts stems not so much from its specific methods as from the theoretical background proposed here and called the ecostratigraphic paradigm. This theory claims that the fossil record of evolution at the community, taxocoene, and/or species group level displays a more or less discrete pattern, with discontinuities imposed mostly by extrinsic, geologic events. This pattern may constitute a base for natural stratigraphic classification of rocks using coenozonal schemes. The ecostratigraphic paradigm may or may not refer to communities as distinct and real biologic units. The greatest advantage of the ecostratigraphic approach is that the resultant set of time‐planes is much more informative about the course of geobiologic evolution than the traditionally used chronostratigraphic one.Stratigraphial theory. ecostratigraphy. chronostratigraphy. paleoecology. coenozones. communities, evolutio

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01066.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01067.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Extremely variable pedicle morphology is described in a large sample of the Recent articulate brachiopodTerebratulina septentrionalis(Couthouy) from off the coast of Nova Scotia. The majority of these specimens were attached to the shells of living or dead scaphopods by a dense network of pedicle rootlets. Other brachiopods had been lying on the sea‐floor anchored solely by the weight of sediment enmeshed within the bush‐like network of pedicle rootlets. Some brachiopod larvae had settled on the exposed pedicle rootlets of adults, presumably because of the scarcity of other suitable substrate. Such a mode of life is thought ‘to indicate that these brachiopods could survive a further reduction in the available substrate and it is suggested that, should such conditions persist, changes in hard‐part morphology would enable descendants of the species to adopt a predominantly free‐lying mode of life. Likely morphological adaptions are suggested, based on examples from the fossil record. This evolutionary trend, from attached to free‐lying and perhaps vice versa, has occurred many times in the history of the Phylum Brachiopoda, and it is suggested that the mode of life of thisT. septentrionalispopulation provides an important insight into at least one of the possible evolutionary pathways which bring about such tran

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01068.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The dense fibro‐lamellar skeleton of lophiostromatids (Stromatoporoidea) is closely similar to the trabecular skeleton of protaraeids (Heliolitoidea) and, respectively, the cystose skeleton of labechiids is similar to that of proporids. They can be interpreted as different types of basal exoskeleton of colonial coelenterates. The main difference between these ancient stromatoporoids and heliolitids is in the arrangement of zooids in the colony, that in the heliolitids enabled them to participate in skeleton building, which was not possible in the stromatoporoids. The stratigraphical distribution supports the supposition of their cummon origin.Coelenterata, Stromatoporoidea, Heliolitoidea. skeleton formation, morpholog

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01069.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01070.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Ecological and statistical analyses of the Late Frasnian (Late Devonian) fauna of the Java Group of New York reveals the presence of three benthic marine communities. Using sedimentological and stratigraphic criteria, the Java Group may be divided into five physical‐environmental zones: nearshore marine, platform, prodelta, open shelf, and slope and basin. TheAmbocoelia‐ Cariniferella, Tylothyris‐Schizophoria. and Cyrtospirifer‐DouvillinaCommunities inhabited open shelf, outer platform ‐ prodelta, and inner platform ‐ nearshore habitats. respectively. Java species gradient curves overlap each other continuously, and species optima replace each other in a regular fashion along the onshore‐offshore environmental gradient. No evidence for competitive exclusion between species or sharp habitat discontinuities (ecotones) is seen for Java ecosystems. The same three‐fold division of communities, in equivalent habitats, can be seen in central Appalachian marine environments located approximately 500 km away along the ancient shoreline. The distribution of communities in this region appears to be directly related to the position and relative size of fluviodeltaic systems along the 500 km of ancient coastline.Palacoecology. communities, Braschiopoda. palaegeography. Devonian. Frasnian, Appalach

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01071.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01072.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The trilobite faunas found in carbonate buildups throughout much of the Paleozoic are remarkably similar in both composition and general morphological characteristics. This is primarily the result of the domination of these faunas by a limited number of trilobite families which are long‐ranging in the buildup environment. Illaenids are the dominant trilobites in Ordovician‐Devonian buildups and are generally accompanied by members of the Lichidae and Cheiruridae. Proetid trilobites are characteristic of Ordovician‐Permian buildups but are seldom common. The number of trilobite families found in carbonate buildups is highest in the late Ordovician, with most of the important families persisting into the Devonian. After the Devonian only proetids are found in this environment. The conservative nature of these trilobite faunas suggests that the environmental characteristics of normal‐marine Paleozoic carbonate buildups are similar.Trilobita, palaeoecology, faunistics, morphology. carbonate buildups. Pal

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01073.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Re‐examination of ammonite specimens with the aptychus apparently in place closing the aperture has shown that these are accidents of preservation and have been misinterpreted as indicating that aptychi functioned as opercula. There remain no convincing grounds for doubting that aptychi functioned only as lower jaws of ammonites, not as opercula. Chance preservation of exceptional specimens can sometimes be misleading.Ammonoidea, aptychi, anoptychi, functional morpholog

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01074.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1981.tb01075.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY