Hello,

As you have noticed I have already had a very complete answer from Masahi from Japan.

Thank you!


Jan Haspeslagh

Masashi Yamaguchi wrote:

> Dear Jan,
>
> >The author uses an index to explain the differences between slow and fast
> burrowers. E.g. the >genus Donax is given an index of 17, indicating that
> this is a very fast burrower.
>
> Vermeij used the burrowing rate index (B.R.I) that was defined by S. M.
> Stanley
> (1970, Relation of Shell Form to Life Habits in the Bivalvia (Mollusca),
> published by
> the Geological Society of America). In the page 57, there is an equation to
> define
> this and the actual data are listed for many species in the Table 6, p.
> 102-105.
> The mean B.R.I. for Donax denticulata is listed as 17. (For D. varabilis,it
> is 7).
>
> The index was designed for standardization in the rate for different sizes
> of the
> same species, so that the specific comparisons are meaningful. The
> equation
> is a simple one: B.R.I. is the cube root of the mass in grams of the live
> shell, divided
> by burrowing time in seconds, times 100. By this way, the index can be
> nearly constant
> for different sizes of the same species. Then, inter-specific comparison can
> be made:
> if the index number was greater than 6, the bivalve was classified as  $B!H (Jvery  (J
> rapid $B!I (J, (J
> 2 to 5 as  $B!H (Jrapid $B!I (J, 0.6 to 1 as  $B!H (Jmoderately rapid $B!I (J, 0.1 to 0.5  $B!H (Jslow $B!I (J  (J
> and less than 0.09
>  $B!H (Jvery slow $B!I (J. (Stanley $B!G (Js Table 4, p. 57) (J
>
> The reasoning for this procedure was described in detail in p. 56, but the
> above
> explanation should be good enough.   Hope this can help the person in need
> of
> the information.
>
> Masashi Yamaguchi
>
> Masashi Yamaguchi
> e-mail: [log in to unmask]
> HTTP://www2s.biglobe.ne.jp/~big/coral/
> Department of Marine Sciences,
> University of the Ryukyus,
> 1 Senbaru, Nishihara, Okinawa 903-0213  Japan

--
Jan Haspeslagh
bibliothecaris/librarian VLIZ

email : [log in to unmask]

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