ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652624

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

During the 18th and early 19th centuries many decapod larvae were briefly described from the N. Atlantic and assigned generic names since they were believed to be adult forms. The earliest accounts are by Leeuwenhoek (1699) and Linnaeus (1767). Metamorphoses in crustaceans was suggested by Slabber (1778) and further proof was provided by Thompson (1820–30) and Du Cane (1839). Knowledge of larval morphology gradually improved through studies chiefly by Muller in the 1860s, Claus and Dohrn in the 1870s and Sars and Cano during the 1880s to 1900s. Significant advances were made in the first half of this century by H. C. Williamson, Robert Gurney, K. Stephensen, H. J. Hansen, Marie Lebour and R. Santucci. Larval stages are now known for approximately 45% of decapod species reported from the area resulting from research combined with improved rearing methods. In the future taxonomic descriptions could be improved by including setal types and their patterns for all developmental stages. Greater use could be made of DNA analyses for investigating taxonomic relationships of larvae. It would seem desirable also to establish an electronic data bank of larval descriptions of species known from the region and to make this available through the Internet.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652625

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The setal morphology is described for the larval stages of the solenocerid shrimpPleoticus muelleribased upon scanning electron microscope studies. Sixty-five different types of setae are recognized and some currently used terms for describing setae are reviewed.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652626

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

There is a need for improvement and standardization in larval descriptions for them to become useful not only for identification purposes but also in comparative and phylogenetic studies. Details of the rearing technique and equipment used should be given, the spent female crab and representative larval stages need to be deposited at a national museum and a minimum of five specimens of each stage should be used for meristic and morphometric criteria. Diagnostic features of the carapace, all appendages, abdomen, and other characters that are to be included in a standard larval description are presented with specifications concerning format and sequence of substructures. Typical configurations of larval structures are given and some possible exceptions are described. Guidelines for illustrations including the preparation, size, sequence and arrangement of figures are provided.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652627

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

From laboratory reared material, the zoeal, megalop and first crab stages ofLibinia spinosaH. Milne Edwards, 1834 are described. A reappraisal of zoeal characters is made by comparing the results of this present study with the descriptions of Boschi and Scelzo (1967) and the larval material ofL. ferreiraeDe Brito Capello (1871) reared by de Bakker et al. (1990). The two zoeal stages ofLibinia spinosaare further compared with those ofPisa armata(Latreille, 1803).

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652628

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In meroplanktonic larvae, growth is accompanied by developmental changes in physiological, biochemical, morphological, behavioural, and ecological traits, and these patterns are further modified by variations in the physico-chemical environment. This paper reviews patterns of growth and chemical composition in planktotrophic marine decapod larvae developing under constant close to optimal conditions, as well as some alterations imposed on these patterns by nutritional, thermal, osmotic, or other stress. Different suboptimal conditions such as food limitation, unsuitable temperatures, or low salinity stress may exert similar bioenergetic effects which, in general, can be measured as a decline in the rates of development and growth or in changing proportions of chemical constituents of larval biomass. The fractions of carbon (C), total lipids, triacylglycerides (TAG), polyunsaturated fatty acids (PUFA), RNA, and ratios of carboninitrogen (C:N), lipid:protein, TAG:total polar lipid, and RNA:DNA have been used as chemical indicators of physiological condition. Quantitative relationships between elemental (C, N) and proximate biochemical fractions (lipid, protein) may vary with nutritional condition, developmental mode (planktotrophy vs. lecithotrophy), clade, and possibly, between field-caught and laboratory-reared larvae (“domestication effects”). Besides further comparative laboratory investigations, more field data are necessary to increase the realism of our models of larval growth and development in the Decapoda and other crustaceans.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652629

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

From the results of studies conducted from the 1960s, three patterns of ontogeny of postembryonic osmoregulation in crustaceans may be distinguished: (1) osmoregulation varies little with developmental stage and the adults are often weak regulators or osmoconformers;(2) the adult type of osmoregulation is established in the first postembryonic stage; (3) metamorphosis marks the appearance of the adult type of osmoregulation. The occurrence of osmoregulation is based on efficient ionic regulation (mainly of Na+ and CI−) and increased levels of Na+-K+ATPase activity. Osmoregulatory epithelia may appear at different times of development and at different locations of the branchial chamber. These events are inter-related, and are correlated with changes in salinity tolerance. In species the eggs of which are exposed to the external medium, either embryos are osmotically protected by the egg envelopes, or the egg membranes and/or the embryos acquire the ability to osmoregulate. When embryos develop in incubating pouches enclosed in the female's body, where they are osmotically protected, they may also become progressively able to osmoregulate. Throughout the development of crustaceans, osmoregulation appears as a key adaptative factor to one or several habitats.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652630

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Based on the accounts by various authors, an identification key has been constructed for the planktonic zoeae of the 70 species of Mediterranean Brachyura whose larvae are known. The key is based on primary (spines of the carapace, exopodite of the antenna, spines of telson forks) as well as secondary (setation of mouthparts, processes and spines on abdominal somites) morphological characteristics. It allows the identification of the zoeae of 64 species plus those ofLiocarcinusgenus (six species).

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652631

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Horizontal planktonic catches made in the Gulf of Tigullio (Genoa, Ligurian Sea) have been analyzed with the aim of identifying the zoeae of Brachyura, whose knowledge is poor in all the northern Mediterranean Sea. Forty-four taxa (42 species plusLiocarcinusspp. andBrachynotusspp.) have been identified, 12 of which were present with all the larval stages. The seasonal distribution of the taxa has been analyzed, and it was possible to recognize species present throughout the year as well as spring/summer, summer/autumn, and winter/summer species. Problems regarding zoeae of dubious identification are discussed.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652632

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

There is a latitudinal gradient in the species richness of Decapoda with pelagic larvae. For example, only two species of Brachyura are found around Svalbard, 54 species are known from the English Channel and ~100 from the Atlantic coast of the Iberian peninsula. The distributions of many species are limited by effects of temperature. Intermoult times of larvae are inversely related to temperature. In the field the size of larvae is inversely related to temperature, the relationship tending to increase in significance in successive larval stages. The timing of the seasonal occurrence of larvae of decapod species in the plankton is also related to temperature, to a greater extent than are seasonal cycles of the holoplankton. These effects of temperature on larval development influence the biomass and production of the larvae in the plankton. Some potential effects of climate change on the distributions and dynamics of planktonic larvae of decapods and consequent changes in their diversity, biomass and production can be predicted insofar as temperature is a limiting factor.

ISSN:0792-4259    

DOI:10.1080/07924259.1998.9652633

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor