THE NAUTILUS 102(4):149-153, 1988
Page 149
Two New Species of Metula (Gastropoda: Buccinidae) with a
Description of the Radula of the Genus
Philippe Bouchet
Museum National d'Histoire Naturelle
55, rue Buffoii
75005 Paris, France
ABSTRACT
Two species of Metula H. and A. Adams, 1853, lack a radula,
and it is very small in a third species. The morphology of the
teeth is significantly different from that in Pisaiiia, and the two
genera are probably not closeK related Metula crosnicri new
species, from 400-450 m off SW Madagascar, is a large, broad
species, with \ery convex whorls and a deep suture. Metula
africana new species, from the deep continental shelf off West
Africa, is considered the descendant of the Mediterranean Plio-
cene M. milraeformis (Brocchi, 1814). This lineage cannot be
taken as evidence for Mediterranean-Indo-Pacific connections
in the lower Pliocene as claimed by Grecchi (1978).
INTRODUCTION
The chequered taxonomical history of the generic name
Metula H. and A. Adams, 1853, has recently been sta-
bilized by Emerson (1986), who clarified the identity of
its type species, Buccinum clathratitm Adams and Reeve,
1850. Additional information was provided by Beu and
Maxwell (1987).
The familial position of the genus has been the subject
of a controversy between Ponder (1968, 1973) and Cer-
nohorsky (1971). Ponder (1968) described the anatomy
of Ratifitsus Iredaie, 1919, and Iredalula Finlay, 1927;
he concluded that their peculiar glandular mid-esoph-
agus as well as other features of the anterior alimentary
canal justified their inclusion in the family Colubrariidae,
which he considered to be anatomically distinct from
the Buccinidae. Cernohorsky (1971) regarded the pres-
ence of a vestigial radula in Ratifusus and Iredalula to
indicate placement in the Buccinidae, since the species
of Colubrariidae have no radula at all, and he suggested
a placement in the buccinid subfamily Pisaniinae. This
view has been accepted by most subsequent authors deal-
ing with Metula (Olsson and Bayer, 1972; Kilburn, 1975;
Houbrick, 1984; Emerson, 1986), who apparently over-
looked Ponder s (1973) refutation of Cernohorsky s point
of view. Ponder (1973) confirmed that Ratifusus, Ire-
dalula. and Colubraria shared the same anatomical char-
acters that separate them from the Buccinidae, and com-
mented on the radular differences: "It thus appears that
some Colubrariidae have lost the radula and that it is
relatively small or vestigial in the remainder. It is possible
that the whole Metula-Ratifusus series discussed by Cer-
nohorsky (1971) belongs in the Colubrariidae as they all
have similar shell features" (Ponder, 1973:328).
The family Colubrariidae is treated as a synonym of
Buccininae by Ponder and Waren (1988), while Beu and
Maxwell (1987) recognize a subfamily Pisaniinae, where
they include Metula, Colubraria, and a number of other
genera.
The purpose of the present paper is to provide a name
for the West African species that has been known in the
recent literature as Metula clathrata Adams and Reeve,
and to describe another new Metula from the upper
continental slope in the Mozambique channel. Several
additional Indo-Pacific species of Metula, now under
study, can be distinguished only on the basis of their
protoconch, which has already been emphasized by Al-
tena (1949) as a taxonomical character.
SYSTEMATICS
The radula of a species of Metula is figured here for the
first time (figure 1). It is very small for a buccinid (ribbon
25 ;um wide; central tooth 6.5 ^m wide, lateral teeth 12
^m wide) and very similar to the radulae of Ratifusus
and Iredalula figured by Ponder (1968): the central tooth
has a narrow arched basal plate with 3 long, slender, and
equal cusps; the lateral teeth also have a narrow basal
plate and 3 long slender cusps, the outermost one being
longest.
A radula has been looked for, but not found in Metula
amosi Vanatta, 1913, and M. cumingi (Adams, 1853);
several specimens were examined in each case by A.
Waren (personal communication). I do not consider pres-
ence or absence of this very reduced radula to be of
generic importance.
The radula (figure 2) of Pisania striata (Gmelin, 1791),
tvpe species of Pisania, is 150 ^m wide; it differs in
having a central tooth with a large square basal plate
and 5 short and broad cusps, the outermost 2 being small-
er; the lateral teeth are more strongly built, with 3 un-
equal cusps.
In view of the small variation of radular types in buc-
BioStor
