Cookies Policy

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

I accept this policy

Find out more here


No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.

Brill’s MyBook program is exclusively available on BrillOnline Books and Journals. Students and scholars affiliated with an institution that has purchased a Brill E-Book on the BrillOnline platform automatically have access to the MyBook option for the title(s) acquired by the Library. Brill MyBook is a print-on-demand paperback copy which is sold at a favorably uniform low price.

Access this article

+ Tax (if applicable)
Add to Favorites
You must be logged in to use this functionality

image of Journal of Crustacean Biology

ABSTRACT The taxonomy of the genus Fredius Pretzmann, 1967, is reviewed, and new taxa are described: Fredius adpressus, F. adpressus piaroensis, F. platyacanthus, and F. estevisi siapensis. The 8 species of this genus inhabit 4 major basins of different geological age in northern South America. The Orinoco basin is the oldest, followed by the Essequibo-Cuyuni basin. The lower Amazon basin, formed from Tertiary to Holocene by alluvionic deposition, is younger than these two. The Atlantic area, formed mainly by marine regressions, is the youngest. The phylogenetic relationships within Fredius, studied by means of a cladistic analysis, were compared with the relationships of these areas using Brooks parsimony analysis. The phylogenetic data fully agree with the area cladogram. The position of the ancestors within the area cladogram shows that most of them were present in a hypothetical major basin comprising the present Orinoco, Essequibo, and Cuyuni rivers, and that much of the evolution of the group occurred there. There is some ambiguity about the possible origin of 2 widespread species. The most parsimonious explanation for one of them is that it originated in the Atlantic drainage and then dispersed into the lower Amazon basin.

Affiliations: 1: (GR) Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Apdo. 21827, Caracas 1010A, Venezuela; 2: (GP) Instituto de Zoologia, Universidad Central de Venezuela, Apdo. 47058, Caracas 1041A, Venezuela.


Full text loading...


Data & Media loading...

Article metrics loading...



Can't access your account?
  • Tools

  • Add to Favorites
  • Printable version
  • Email this page
  • Subscribe to ToC alert
  • Get permissions
  • Recommend to your library

    You must fill out fields marked with: *

    Librarian details
    Your details
    Why are you recommending this title?
    Select reason:
    Journal of Crustacean Biology — Recommend this title to your library
  • Export citations
  • Key

  • Full access
  • Open Access
  • Partial/No accessInformation