HI Volutists,
Systematic classification of South American Volutes have been always
hard to elaborate. Conventionaly, they have been divided into Zidoninae
A.&H.Adams,1853 and Odontocymbiolinae Clench & Turner,1964.. Differences
are founded on radula shape and some minor attachement of digestive
glands.
Indeed the true problem is what exact suprageneric value we can impute
to morphology of radula,in comparison with strong conchological features
such as shape of protoconch,spire,columella and texture of shell test?
Radula is subdued to a higher evolutionary pressure than shell
morphology.It can be rapidly alterared by a modification of substratum
with change of usual preys. Very large difference of radula is found in
different Subfamily such as Amoriinae and Scaphellinae without need of
splitting into separate Subfamily.
To merge Zidoninae and Odontocymbiolinae could be a simplification may
be coherent with their close relationships.This idea was already lead by
Stuardo & Villaroel (1974) and Darragh (1988).In this hypothesis, the
wide Subfamily Zidoninae can be divided into geographical Tribes:
-Australian Tribe (Ericusa,Livonia, Notopeplum)
-New-Zeland Tribe (Alcithoe,Zygomelon)
-West African Tribe (Cymbium)
-Circum-antartic Tribe (Zidona,Provocator,Harpovoluta)
-Two south American Tribe:(Adelomelon,Nanomelon,and ..Arctomelon) and
(Odontocymbiola,Miomelon,Minicymbiola,Tractolira),
No place for Argentovoluta bottai (Vasquez & Caldini,1989),a doubtful
Volutidae? The same authors described in 1992 Odontocymbiola canigiai,
very hard to differenciate from Odontocymbiola magellanica and in 1990
Odontocymbiola rucciana,a very light, whitish with a  green periostracum
pescalia-like shell.I just read that J.H.Leal consider it as conspecific
with O.pescalia. A pertinent opinion we can easily agree.
All the best         Pat Bail