ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb02256.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Possible alternative habitats and life‐styles of the original metazoan are considered. It is argued from the dominance of the benthic habitat in present‐day groups that the original metazoan habitat was benthic rather than planktonic. Similarly, plesiomorphic metazoan taxa tend to be holobenthic rather than pelago‐benthic. It is therefore probable that the early Metazoa were holobenthic. The concept of plesiohabitats and apohabitats in the evolution of taxa is presented. This leads to the proposition that the early metazoans were interstitial bionts of fine sand. Finally, the controversy concerning the aerobic or anaerobic origin of the Metazoa is considered. It is shown that competition theory predicts that plesiomorphic taxa are likely to remain in plesiohabitats. Diagrams showing the possible evolution of major taxa in relation to available habitats are presented. It is concluded that the earliest Metazoa could have evolved in anaerobic marine sand and that the early Plathelminthomorpha and Aschelminthes d

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb02257.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The meiobenthos are regarded as the first metazoans to appear on earth This paper considers some aspects of their role in the marine ecosystem over evolutionary time. It is speculatively suggested that they have had a profound influence on many structural and functional attributes of the marine ecosystem as we see it today, both in the benthic and pelagic realms. Certain features such as size spectra, the life‐history characteristics of the macrobenthos, and the energetic balance between ecological compartments of the marine ecosystem are considered to result from evolution away from negative interactions with the meiobentho

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb02258.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

After briefly reviewing the evidence that meiofauna are an integral part of the complex food web of invertebrate infaunal and epifaunal organisms, it is shown that, at least in intertidal and shallow subtidal habitats, meiofauna are an important food for the small (30–60 mm) juveniles of some commercially important fishes (flatfish and salmonids) or for fish which are themselves food for commercial species. The evidence that fish feed preferentially on a few species of harpacticoid copepod rather than on the numerically dominant meiofaunal taxa is presented and discussed. It is argued that, in addition to benthic copepods being energetically efficient as food for fishes, it is differences in the activity and availability between major taxa of meiofauna as they relate to the feeding strategies of the fish which go a long way to explaining this apparent general preference of fish for harpacticoid copepods rather than nematodes. From literature estimates of consumption rates, it is concluded that the supply of meiofaunal food to juvenile fish is unlikely to be limiting although this may not be the case in some shallow subtidal muddy sand habitats. Whilst it is recognized that fish predation may influence the magnitude of the seasonal peaks in numbers, predation is not the principal cause of seasonal fluctuations in harpacticoid copepod species abundances. The effects of predation on other aspects of community structure is unknown. Finally, the possible role of meiofauna in mariculture systems is briefly discusse

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb02259.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The use of meiofaunal assemblages for the detection and quantification of perturbation of the marine environment by man is examined. The theoretical and practical advantages and drawbacks of meiofaunal monitoring are described and different methods of impact assessment described and evaluated. It is suggested that identification of meiofaunal material need not present a major obstacle to its use, as sensitive responses of meiofaunal assemblages to pollution can be recorded without the necessity for specific identifications. It is concluded that the great sensitivity to pollution of some meiofaunal groups (particularly copepods) offers the potential for better estimation of the real extent of pollution impact than is being achieved by sole reliance on examination of the macrofaunal assemblage. Meiofaunal monitoring should also be considered where there is difficulty in adequate sampling of the macrofauna, due to impoverishment or practical difficulties.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb02260.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The genusRostangaBergh, 1879 is reviewed and ten species, seven of them new, are recognized from the Indo‐West Pacific. They are compared with the three species of the genus known from elsewhere in the world. Most species are red or orange‐red and the mantle is characterized by a dense covering of spiculate caryophyllidia. Species are characterized on aspects of the buccal armature, rhinophore club, egg‐ring, developmental biology and food preferences. Each species has a specialized diet, most species restricted to one or a few sponges of the family Microcio

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb02261.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY