deal all
the theme of the evolution of larval development in marine invertebrates
has been my preferred one during several years. And it was the argument of
my very PhD thesis (1994). I have neglected it for a while but I'm still
accumulating data about several aspects. One of them is the phenomenon of
pais of species. I was thinking about presenting a poster to the next
UNITAS congress in Australia (2004).

Palaeontological data from the North-East Atlantic area (including the
Mediterranean Sea) indicate a clear trend toward the loss of planktotrophy
in several caeonogastropod lineages (Oliverio & Sabelli, unpublished). The
genera Neverita, Nassarius, Trophon, Haedropleura, Clathromangelia and
Raphitoma, are but a few of these examples. Presently, the N.E. Atlantic
prosobranch fauna includes a large number of pairs of closely related
species differing mainly or only in the developmental strategy. In some
cases additional morphological differences indicate that different species
are involved. In other cases, the only evident difference is that of their
larval development. This phenomenon was first pointed out by Verduin in a
series of papers (1976a, 1976b, 1977, 1982, 1985, 1986a, 1986b).
Noteworthy, it is known that variation in larval development is not
exclusive to molluscs, nor the the NEAtlantic. Examples of pairs of sibling
species, or of species-complexes, where the evolution of the larval
development played a crucial role in their diversification, can be scored,
even at first sight in the major families of caenogastropods.
Muricidae: Murex tribulus L. 1758 vs. its sibling Murex forskaeli Lischke,
1868,
Naquetia triqueter (Born, 1778) vs. Naquetia cumingi (A. Adams, 1853)

Conidae: C. textile group: C. textilinus from the Marquesas has a
planktotrophic larval development while C. dalli Stearns, 1873, from the
Panamic region lacks the planktotrophic phase. In Madagascar cones of the
textile group are known that, according to larval shell dimensions probably
have non-planktotrophic larval development (G. Raybaudi, pers. comm.).
Conus omaria Hwass, 1792 vs. C. madagascariensis Sowerby II, 1858
C. aureus Hwass, 1792 vs. C barbieri
C. capitaneus L., 1758 vs. C. trigonus Reeve, 1848.

This is just a summary of a much longer list of pairs from many different
familes.

Well, my question to CONCH-L is:
I would like to compile a list of as many as possible pairs of species
(planktotrophic vs. non-planktotrophic) from all oceans.
If those of you who have any data, would share them it would be very
interesting. You can send your own data to the list (or to me: as you
prefer) and I can try to have a more complete dataset to elaborate.
Geographic range of each species would be required, and also any other data
available (references, ecology, images etc ... ).

Well thanks for your help
marco


=========================================================
Marco Oliverio - Evolutionary Biology PhD
Research Scientist

Dipartimento di Biologia Animale e dell'Uomo
Viale dell'Universita' 32
I-00185 Roma   ITALY

phone  +39.06.49914307
FAX    +39.06.4958259
e-mail: [log in to unmask]