The Clavatulidae (Gastropoda, Conoidea) of the Miocene Paratethys Sea with considerations on fossil and extant Clavatulidae genera
Author
Harzhauser, Mathias
0000-0002-4471-6655
mathias.harzhauser@nhm-wien.ac.at
Author
Landau, Bernard
0000-0002-7768-8494
bernardmlandau@gmail.com
Author
Janssen, Ronald
0000-0002-4471-6655
mathias.harzhauser@nhm-wien.ac.at
text
Zootaxa
2022
2022-03-30
5123
1
1
172
http://dx.doi.org/10.11646/zootaxa.5123.1.1
journal article
10.11646/zootaxa.5123.1.1
1175-5326
6399827
036F6B4D-CDCC-4CD7-A914-9A1D8C7A097A
Genus
Scaevatula
Gofas, 1990
Type
species.
Scaevatula pellisserpentis
Gofas, 1990
.
Present-day
,
São Tomé
(Gulf of
Guinea
)
.
Diagnosis.
Small, moderately slender fusiform sinistral or dextral shells with high spire and low last whorl. Narrow subsutural collar with beads; entire shells with dense sculpture of axial ribs and spiral cords. Base slowly contracting. Siphonal canal short, relatively wide, deflected to the left. Aperture ovoid with thin and smooth outer lip. Columellar and parietal callus forming rim. Low, dome shaped, paucispiral protoconch with broad axial ribs.
Discussion.
The genus was based by
Gofas (1990)
on a sinistral species from
São Tomé
(Gulf of
Guinea
). Later,
Rolán & Fernandes (1993)
described a second species from the same region as
Scaevatula amancioi
, which is dextrally coiled.The peculiar sculpture and especially the protoconch sculpture, which is unique within
Clavatulidae
, strongly suggest that both species belong to the same genus, despite the opposite coiling. Little information is available on the ecology of this genus, which occurs in few meters water depth (
Rolán & Fernandes 1993
). Both extant species range around
6 to 8 mm
in height and thus are much smaller than the Paratethyan
Scaevatula sidoniae
(
Hoernes & Auinger, 1891
)
, which attains
24.8 mm
in height. Moreover, the Miocene species is more solid and bears inner lirae, which are unknown from extant
Scaevatula
. The sculpture of
Scaevatula amancioi
, in contrast, is very similar to that of
S. sidoniae
and both develop a bipartite sculpture of early teleoconch whorls. Finally, the sculptured protoconch is so unusual in
Clavatulidae
that we provisionally place the Miocene species in
Scaevatula
.
Scaevatula sidoniae
is slightly reminiscent of
Granulatocincta
nov. gen.
concerning its sculpture, but differs in its bipartite early teleoconch sculpture.
Paleoenvironment.
Coastal inner neritic environments (
Gofas 1990
).
Distribution and stratigraphy.
Scaevatula
was known so far only from the modern fauna of tropical West Africa. Our Miocene record from the Paratethyan Sea is the first fossil record of the genus and an additional proof of a faunistic relation between the tropical Eastern Atlantic and the Paratethys Sea, which is documented also for
Clavatula
and
Perrona
.