摘要:

Modern coralline sponges secrete a skeleton by means of a basal pinacoderm, intracellularly, or inside the soft tissue on an organic matrix The examination of terminal growth surfaces of stromatoporoids indicates that soft tissue in laminate and amalgamate forms occupied the upper galleries and that the skeletal elements were secreted within the soft tissue on an organic matrix. The stromatoporellids and clathrodictyids secreted the skeleton in modules that are homologous to the chambers of a sphinctozoan. In stromatoporellids the module was bounded by a floor that formed the upper layer of the tripatite lamina below and a roof that became the lower layer of the next lamina; it further included the intervening pillars. In clathrodictyids the module had only a roof and pillars, and the laminae are single layers. other stromatoporoids may have secreted their skeletons at the base of the soft tissue and had minimal occupation of the skeleton. ***Stromatoporoid, sphinctozoa, sclerospongiae, sponge, paleobiology.

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01547.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Lower Palaeozoic palaeoscolecid worms have usually been referred to the phylum Annelida, albeit often with a question‐mark, The find of palaeoscolecids with armed proboscis in the Lower Cambrian Chengjiang fauna from Yunnan, southwest China, provides evidence that these worms were aschelminths. They are similar to the Nematoda, Priapulida, and Nematomorpha and presumably closest to the latter, although not parasitic. The palaeoscolecids appear to be just one of several ‘armoured‐worm’ radiations among the earliest representatives of modem phyla, as suggested by the plentitude of ‘small shelly fossils’ in the Lower Cambrian. ***Aschelminthes, Cambrian, Chengjiang fauna, Nematomorpha, Pala

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01548.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01549.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A new ecological unit within the well‐documented late Ordovician brachiopodFoliomenafauna is defined on the basis of assemblages from Northern Cuizhou and southern Sichuan. Southwest China. TheKassinella‐ChrisrianiaAssociation, from the lower Ashgill Linhsiang and Chientsaokou formations, is dominated by the eponymous genera together with species of mainlyDedzetina, SericoideaandKozlowskites Foliomenais rare or absent. To date, theFoliomenafauna has been documented only from deep‐water environments however, the new association apparently occupied shallower depths, probably in lowermost Benthic Assemblage Zone 3 and uppermost Benthic Assemblage Zone 4, presumably at the shallow end of the depth range of theFoliomerefauna. The incursion of theFoliomenafauna into relatively shallow‐water environments may have been encouraged by abnormally low oxygen levels and sparse nutrients together with persistent soft substrates across this part of the Yangtze Platform during the early Ashgill. ***Ordovician, Ashgill, China, brachiopods. Foliome

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01550.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Xenophyophores, a group of agglutinated rhizopod protists, occur in nearly all the world's oceans at depths generally in excess of 1OOO m. In certain areas they dominate deep‐sea, megafaunal communities. Their widespread distribution indicates a well‐established adaptive radiation. Only one fossil analogue, however, has been proposed. This isPaleodictyon, a trace fossil that superficially resembles the Recent infaunal xenophyophoreOccultammina profundain morphology. The platy xenophyophore genusPsamminaclosely resembles certain late Palaeozoic fossils from northeastern Kansas that have been referred to as ‘phylloid algae’. Here we compare modern xenophyophore structure with that of the fossil phylloids. By reconstructing the fossils, analysing their thin sections with polarized, blue, and ultraviolet light and subjecting them to Q‐switched laser ablation, we conclude that certain phylloids could represent shallow‐water xenophyophores. ***Phylloid algae, xenophyophores, motphology, reconstruction, laser ablation, Pe

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01551.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01552.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

An Early Jurassic (Sinemurian) reef in the Telkawa Range, British Columbia Canada, yields coral species previously known from Morocco, Great Britain, Italy, Peru, and Chile. The principal constructional coral,Phacelostylophyllum rugosum(Laube), known from the Upper Triassic Dolomite Alps in northern Italy, is a holdover species. This coral survived the mass extinctions of the end‐Triassic without leaving any other Jurassic records outside Canada. Other corals from the Telkwa reef includeStylophyllopsis victoriae(Duncan) andActinastraea minimaBeauvais known from Jurassic rocks of the Tethys. Closely related corals,Phacelostylophyllum chocolatensis(Wells) andActinastraea plana(Duncan), are from southern Peru. The paleogeographic Occurrence of the Canadian reef in the volcanic terrane of Stikinia supports the contention that volcanic islands in distant outposts of the ancient Pacific served as refugia. In the aftermath of the end‐Triassic reef decimation affecting the Tethys, corals and reef‐building activities continued on ancient islands of the ancestral Pacific. The Hispanic Corridor, connecting the western Tethys with the western Pacific, may have played an important role during Sinemurian time.***Reef; corals, Triassic, Jurassic, extinctions, paleobiogeog

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01553.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01554.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Remarkable large pits were found on the shell surface of many ammonites from the Turonian‐Maastrichtian sediments of Hokkaido, northern Japan, and Sakhalin, Russia. These pits are (1) round to elliptical in shape; (2) up to 20 mm (usually around 10 mm) in diameter; (3) shallow depressions to deep holes that almost penetrate the shell: (4) occasionally healed by a thin shell blister from inside the shell; (5) often overlapping one another; (6) several to more than 170 in number on one flank of the ammonites; (7) found on both flanks and predominantly on the body chamber and the final volution of the phragmocone; and (8) found only in the two families Pachydiscidae and Puzosiidae, predominantly of more than 300 mm in shell diameter. They can best be interpreted as the home depressions of patellogastropod limpets. The presence of pits on both flanks of the ammonites and those healed from inside the shell strongly suggest that the limpets were dwelling on mature swimming ammonites. Host specifity, their very small shell size compared with the host ammonites, and sparse Occurrence in sediments favor a mode of life as obligate pseudoplankton. We suggest that this remarkable limpet‐ammonite association was well established in northwestern Pacific bioprovinces during the late Cretaceous. Taking this live association and the depth limit of algal growth as food for the limpets into consideration, the mature ammonites dwelled or periodically visited the upper layer of the euphotic zone, probably less than around 20 m in depth. ***Ammonite, limpet, home depression, life mode, pseudoplankton, Cretace

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01555.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The Neogene cheilostomatous bryozoanCelleporaria palmatalived facultatively in association with the scleractinian coralCulicia.ForCuliciathe association was obligatory; the symbiosis was most probably mutualistic. Benefits for the coral appear to have been: (1) the bryozoan provided substrate in a soft‐bottom environment; (2) the coral could feed at higher levels above the sediment; (3) the feeding currents generated by the bryozoan provided the corals with food (no competition for food would occur as the coral would collect larger prey); and (4) the surrounding of the cordites by the bryozoan provided strength and lateral protection. Benefits for the bryozoan appear to have been: (1) the stinging cells of the coral provided protection against predators and settlers; (2) the positioning of the corals on the maculae saved the bryozoan subsequent energy expenditure in further construction of polymorphs and secondary calcification. Negative effects for the bryozoan might have been the inhibition of possible functions of the maculae other than as exhalant chimneys, e.g., production and generation of male gametes. ***Symbiosis, mutualism, Culicia, Cryptangia, Celleporaria, Bryozoa, Scleractini

ISSN:0024-1164    

DOI:10.1111/j.1502-3931.1994.tb01556.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY