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
Family
Clavatulidae
Gray, 1853
Although all extant clavatulid species are superficially similar, which has led all authors until now to divide them into two genera (
Clavatula
Lamarck, 1801
and
Perrona
Schumacher, 1817
), on closer examination there are also characters that are shared by some groups of clavatulids and not others. In order to clarify the descriptions given in the systematic section, some discussion on clavatulid shells is required.
FIGURE 3.
Early teleoconch whorls of extant and fossil
Clavatulidae
species.
A.
Clavatula regia
(
Röding, 1798
)
, NHMW 1683 6/28, West Africa.
B.
Clavatula rubrifasciata
(Reeve, 1845)
, NHMW 10203, Gorée (Senegal).
C.
‘
Clavatula
’
diadema
(
Kiener, 1839
), NHMW 1884/0010/0023, Gorée (Senegal).
D.
‘
Clavatula
’
mystica
(
Reeve, 1843
)
, MNHN-IM-2013-59897, Est de l'ile de Gorée (Senegal).
E.
‘
Clavatula
’
bimarginata
(
Lamarck, 1822
), MNHN-IM-2013-43369, Dakar (Senegal).
F.
‘
Clavatula
’
pyramidata
(
Kiener, 1839
)
, MNHN-IM-2009-24982, Baie de Pointe-Noire (Republique du Congo).
G.
Clavatula sorini
nov. sp.
, paratype, NHMW 1874/0025/0046, Lăpugiu de Sus (Romania).
H.
‘
Clavatula
’
romana
(
Defrance, 1826
)
, NHMW 1999/0098/0004, Modra-Kráľová (Slovakia).
I.
‘
Clavatula’
interrupta
(
Brocchi, 1814
)
, NHMW 1861/0033/0420, Buituri (Romania).
J.
‘
Clavatula
’
hirmetzli
Kovács & Vicián, 2021
, NHMW 1868/0001/0069, Baden-Sooss (Austria).
K.
‘
Clavatula
’
irisae
nov. sp., NHMW 2021/0126/0001, holotype, Gainfarn (Austria).
L.
‘
Clavatula
’
sophiae
(
Hoernes & Auinger, 1891
)
, lectotype, NHMW 2021/0127/0001, Enzesfeld (Austria).
M.
‘
Clavatula
’
veronicae
(
Hoernes & Auinger, 1891
)
, NHMW 1855/0043/0044b, Lăpugiu de Sus (Romania).
N.
‘
Clavatula
’
santhai
Kovács & Vicián, 2021
, holotype, HNHM, PAL 2021.20.1, Letkés (Hungary).
O.
‘
Clavatula
’
camillae
(
Hoernes & Auinger, 1891
)
, lectotype, NHMW 1949/0005/0042, Lăpugiu
de Sus (Romania).
P.
Megaclavatula
amaliae
(
Hoernes & Auinger, 1891
)
,
lectotype
, NHMW 1949/0005/0049, Lăpugiu de Sus (Romania).
Q.
Megaclavatula grunerti
nov. sp.
,
paratype
, NHMW 2021/0127/0003, Enzesfeld (Austria).
R.
Megaclavatula laevigata
(
Eichwald, 1830
)
, NHMW 1853/0038/0035a, Korytnica (Poland).
S.
Megaclavatula pilleri
nov. sp.
,
holotype
, NHMW 1949/0005/0051a, Baden-Sooss (Austria).
T.
Megaclavatula polonica
(Pusch, 1837)
, NHMW 1862/0001/0324, Bad Vöslau (Austria).
U.
Granulatocincta angelae
(
Hoernes & Auinger, 1891
)
,
paralectotype
, NHMW 1949/0005/0099, Möllersdorf (Austria).
V.
Granulatocincta granulatocincta
(Münster in Goldfuss, 1841), NHMW 1846/0028/0009, Enzesfeld (Austria).
W.
Granulatocincta nataliae
(
Hoernes & Auinger, 1891
)
, NHMW 1855/0035/0021,
holotype
,
Belgrade
/Rakovica (Serbia).
X.
Granulatocincta schreibersi
(
Hörnes, 1854
)
,
paralectotype
, NHMW1997z0178/1133, Bad Vöslau (Austria).
Y.
Granulatocincta callim
nov. sp.
,
paratype
, NHMW 2021/0128/0001, Bad Sauerbrunn (Austria).
Z.
Granulatocincta contorta
(
Švagrovský, 1958
)
,
holotype
, SNMB Z 3076, Kuzmice (Slovakia),
Aa.
Granulatocincta theoderichi
nov. sp.
,
paratype
, NHMW 2016/0026/0320b, Ritzing (Austria).
Ab.
Olegia doderleini
(
Hörnes, 1854
)
,
paralectotype
, NHMW 1858/0015/0147, Wiesen (Austria).
Ac.
Olegia mandici
nov. sp.
,
paratype
, NHMW 1872/0031/0008a, Bekića vrelo, Čremušnica at Donji Kirin (Croatia).
Ae.
Olegia dorotheae
(
Hoernes & Auinger, 1891
)
,
paralectotype
, NHMW 1949/0005/0040, Kleinebersdorf (
Austria
). Scale bar is
5 mm
for all specimens except for
Granulatocincta contorta
,
Olegia doderleini
and
O. mandici
.
The protoconch of almost all known clavatulid species is paucispiral and almost always unsculptured (exceptions are
Scaevatula
Gofas, 1990
, which has a ribbed protoconch and
Tomellana aueri
nov. sp.
, which has a protoconch of 2.5 whorls). This paucispiral
type
of protoconch is suggestive of direct development, or at least a short planktotrophic phase, which tends to lead to stratigraphically short lived and geographically restricted species (
Jablonski & Lutz 1980
). This is certainly the pattern seen in both the fossil and present-day record and reaches its zenith in the Miocene Paratethys. Unfortunately, the protoconch is rarely preserved in adult specimens in the Paratethys record, however, based on the experience of other clavatulid populations (e.g., Pliocene Atlantic and Mediterranean), it is of limited taxonomic use in distinguishing species (own data B.L.).
The spire in all species is relatively raised and conical, although the outline may be made irregular or somewhat gradate by a strongly developed raised subsutural collar and made coronate by spines or tubercles developed either on the adapical part of the collar or mid-collar. In many species sculpture changes markedly with ontogeny on about the fourth to sixth whorls. Early teleoconch whorls are often divided into two beaded cords separated by a narrow groove or concave area (bipartite), or bear three beaded portions, a subsutural cord, mid-cord and suprasutural cord (tripartite) (
Figs 3–4
). In some species the early teleoconch sculpture is neither bipartite nor tripartite but consists of very narrow adsutural cords and a wide concave mid-portion (e.g.,
‘Clavatula’ jarzynkae
nov. nom.), or a welldeveloped, but smooth, subsutural cord and a suprasutural row of beads separated by a concave portion, as is the case with many of the species placed in
Clavatula
s.l.
herein.
On later teleoconch whorls the subsutural cord swells to form the subsutural collar, the mid-portion beads fade and become smooth or finely spirally striate, and the beads on the suprasutural cord swell and become tubercles. In some species the subsutural cord is not visible, obscured by the succeeding whorl. On the last whorl it becomes clear that the mid-portion on the spire whorls represents the subsutural ramp and the suprasutural row of tubercles coincide with the shoulder (
Fig. 2
).
In all
Conoidea
the anal sinus is an important character, and often useful for separation at both generic and species level. In clavatulids the sinus is well-developed and clearly preserved in all species (
Fig. 5
). On early teleoconch whorls the sinus can be represented by comma-shaped axial riblets but these structures are strong growth lines but do not represent true ribs. Ribs are uncommon in clavatulids, and when present are poorly defined and formed by axially aligned rows of tubercles (i.e., ‘
Clavatula
’
apolloniae
), and are only present on the last whorl below the shoulder.
Spiral elements on the spire whorls are composed of sub- and suprasutural cords on the early whorls, which later become the subsutural collar and suprasutural row of tubercles (as discussed above). Many species have secondary spiral cords that cover the entire surface including the collar and suprasutural tubercles. Spiral sculpture on the last whorl is more variable. The shoulder cord is tubercular (occasionally spinous) in
Clavatula
species
and usually smooth or rarely weakly tubercular in
Perrona
species.
Usually, a peribasal and perifasciolar cord is more prominent, and less often a mid-whorl cord, all of which are more or less tubercular. Rarely a species may have five primary cords below the shoulder (i.e., ‘
Clavatula
’
apolloniae
). Secondary and tertiary spiral sculpture tends to be rather irregular in clavatulids and is often not only present in the interspaces, but overrides the primary cords.
FIGURE 4 A.
‘
Clavatula
’
justinae
(
Hoernes & Auinger, 1891
)
, NHMW ex1949/0005/0110b, Buituri (Romania).
B.
‘
Clavatula
’
mariae
(
Hoernes & Auinger, 1891
)
, lectotype, NHMW 1849/0013/0009, Mold (Austria).
C.
‘
Clavatula
’
olgae
(
Hoernes & Auinger, 1891
)
, lectotype, NHMW 1862/0001/0552, Buituri (Romania).
D.
‘
Clavatula
’
orientoromana
Báldi, 1960
, holotype, M.60.145, Szokolya (Hungary).
E.
‘
Clavatula
’
juliae
(
Hoernes & Auinger 1891
)
, paralectotype, NHMW 1949/0005/0043c, Lăpugiu de Sus (Romania).
F.
‘Clavatula’
apolloniae
(
Hoernes & Auinger, 1891
)
, NHMW 1868/0001/0474a, Lăpugiu de Sus (Romania).
G.
Neoperrona harzhauseri
(
Kovács & Vicián, 2021
)
, NHMW 2019/0151/019a, Letkés (Hungary).
H.
Neoperrona zoltanorum
nov. sp.
, holotype, NHMW 2019/0151/0108, Letkés (Hungary).
I.
Scaevatula sidoniae
(
Hoernes & Auinger, 1891
)
, NHMW 1855/0043/0045, holotype, Lăpugiu de Sus (Romania).
J.
Pusionella palatina
Strausz, 1954
, NHMW 2021/0159/0003, Várpalota (Hungary).
K.
Pusionella hofmanni
nov. sp.
, NHMW 1867/0019/0136, holotype, Coşteiu de Sus (Romania).
L.
Perrona barbarae
(
Hoernes & Auinger, 1891
) NHMW 1949
/0005/0103a, Rückersdorf (Austria).
M.
Perrona descendens
(
Hilber, 1879
)
, NHMW 1846/0049/0017, St. Florian (Austria).
N.
Perrona emmae
(
Hoernes & Auinger 1891
)
, NHMW 2021/0127/0005, Enzesfeld (Austria), NHMW 1970/1396/1449, Baden (Austria).
O.
Perrona ernae
(
Šuklje, 1929
)
,
NHMW 2021/0156/0001, Weinsteig (Austria).
P.
Perrona floriana
(
Hilber, 1879
)
,
holotype
, NHMW 1858/0020/0012, Guglitz at St. Florian (Austria).
Q.
Perrona ilonae
nov. nom.
, M.61.4367, Szentkút, Mátraverebély (Hungary).
R.
Perrona lydiae
(
Hoernes & Auinger, 1891
)
,
lectotype
, NHMW 1949/0005/0112, Gainfarn (Austria).
S.
Perrona oliviae
(
Hoernes & Auinger 1891
)
,
paralectotype
, NHMW 1873/0026/0027, Lăpugiu de Sus (Romania).
T.
Perrona rosaliae
(
Hoernes & Auinger 1891
)
,
lectotype
, NHMW 1999z0098/0002,
Vienna
/Pötzleinsdorf (Austria).
U.
Perrona sabinae
(
Hoernes & Auinger 1891
)
,
paralectotype
, NHMW 2021/0154/0001, Lăpugiu de Sus (Romania).
V.
Perrona styriaca
(
Hilber, 1879
)
,
lectotype
, NHMW 1846/0037/0309, Pöls (Austria).
W.
Perrona ursulae
(
Hoernes & Auinger, 1891
)
,
paralectotype
, NHMW 1846/0001/1294, Buituri (Romania).
X.
Perrona vindobonensis
(Quenstedt, 1884)
,
paralectotype
, NHMW 1997z0178/1467, Gainfarn (Austria),
Y.
Perrona wanzenboecki
nov. nom.
, NHMW 2021/0158/0001,
neotype
, St. Veit an der Triesting (Austria).
Z.
Tomellana dulaii
nov. sp.
, NHMW 2021/0148/0002,
holotype
, Nemeşeşti (Romania).
Aa.
Tomellana aueri
nov. sp.
, NHMW 2013/0078/0436, Baden (Austria).
Ab.
Striopusionella szekelyhidiae
(
Kovács & Vicián, 2021
)
,
holotype
, PAL 2021.19.1, Letkés (Hungary).
Ac.
Scaevatula sidoniae
(
Hoernes & Auinger, 1891
)
. NHMW 1855/0043/0045,
holotype
, Lăpugiu de Sus (Romania). Scale bar is
5 mm
for all specimens except for
Perrona barbarae
and protoconch of
Scaevatula sidoniae
.
FIGURE 5.
Anal sinus morphology of Paratethyan
Clavatulidae
.
Clavatulids often have rows of beads, tubercles, and spines. In this work beads are defined as small round, spirally-aligned structures in apposition to each other. Tubercles are larger, not in contact with each other and can be rounded, subtrigonal or subquadrate in outline and low or pointed, if sharp here called spinous. Spines are also present in some species, which is when the pointed structure, usually on the subsutural collar, is open on the abapical side (e.g.,
Perrona eleonorae
).
FIGURE 6.
Apertures of Paratethyan
Clavatulidae
(
C. =
Clavatula
, ‘C.’ = ‘Clavatula’, G. =
Granulatocincta
, M
.
= Megaclavaltula
,
O. =
Olegia
).
The aperture is pyriform to ovate in clavatulids, the outer lip does not possess a varix, and is usually smooth within (
Figs 6–7
). Species with lirae within the outer lip do occur (e.g.,
Granulatocincta granulatocincta
, ‘
Clavatula
’
irisae
, ‘
Clavatula
’
sophiae
,
inter alia
), and if present are considered a species-specific character in most species (‘
Clavatula
’
romana
is an exception). The siphonal canal is open in all species and usually weakly to moderately notched (exceptions exist). The length of the canal is species specific.
FIGURE 7.
Apertures of Paratethyan
Clavatulidae
(
O. =
Olegia
, ‘
C
.’ = ‘
Clavatula
’,
N. =
Neoperrona
,
P. =
Perrona, Pu.
=
Pusionella, Sc.
=
Scaevatula
, S. =
Striopusionella
, T. =
Tomellana
).
The columella is more or less deeply excavated in the upper third or upper half, more or less twisted at the fasciole, and smooth in all species. The columellar callus is weakly to moderately developed, at most expanded onto the medial side of the venter, but never greatly thickened. The parietal portion of the callus is never thicker than the abapical portion and never develops a callus pad or fold.
No color pattern is present in the Paratethyan specimens, nor is it enhanced by UV.
What is
Clavatula
?
MolluscaBase (Eds.) (2021a) lists 37 species of
Clavatula
, including also
Clavatula xanteni
Nolf & Verstraeten, 2006
, which was placed in
Perrona
by
Kantor
et al
. (2018a)
.
Clavatula pyramidata
(
Kiener, 1839
)
is missing from that list, although
Kantor
et al
. (2018a)
placed that species in
Clavatula
based on molecular data.
Kilburn (1985)
and
Boyer & Hernández (2004)
stated that
Clavatula
is a poorly characterized genus, lacking well-defined diagnostic features, but did not provide solutions.
New unpublished molecular data confirmed
Perrona
,
Tomellana
and
Scaevatula
as genus-level taxa, but are in conflict with
Clavatula
as currently perceived (Nicolas Puillandre, pers. comm.,
October 2021
). These results suggest that
Clavatula
is not monophyletic, which is also suggested by the morphologies of the early teleoconch whorls. We observe peculiar morphologies in certain species groups (
Figs 3A–E
), which we discuss herein as clades.
Clavatula muricata
(
Lamarck, 1822
)
(probably a synonym of
C. regia
) and
C. regia
(
Röding, 1798
)
(
Figs 8A–H
) have a bipartite sculpture with a weak, smooth subsutural cord and a prominent suprasutural cord of large beads (overrun by weak spiral cords) (
Fig. 3A
). The same early teleoconch sculpture is developed by
C. rubrifasciata
(Reeve, 1845)
(
Figs 3B
,
9A–B
) and
C. lelieuri
(
Récluz, 1851
)
(see Nolf 2008: pl. 8, figs 42–49, pl. 9). The
muricata
+
regia
clade contains the
type
species and therefore, these species represent
Clavatula
sensu stricto
.
A close relation of ‘
Clavatula
’
caerulea
(Weinkauff in
Weinkauff & Kobelt, 1875
) and ‘
Clavatula
’
pyramidata
(
Kiener, 1839
)
(
Figs 3F
) with
Clavatula
is suggested by the early teleoconch sculpture with a prominent suprasutural cord of large beads. Both species, however, differ from typical
Clavatula
in their slender fusiform shell with high conical spire, the comparatively short last whorl, and the wider and shorter siphonal canal (
Figs 10A, B
) (see
Nolf and Verstraeten 2008
: pls 1–2 for ‘
C.
’
caerulea
). ‘
Clavatula
’
martensi
von
Maltzan, 1883
and ‘
C.
’
matthiasi
Nolf and Verstraeten, 2008
belong also to this group, based on conchological features (see
Nolf and Verstraeten 2008
: pls 3–5). Herein, we treat these species as
caerulea
-clade.
‘Clavatula’
mystica
(
Reeve, 1843
)
differs from these species by its tripartite sculpture on the first four teleoconch whorls (
Figs 3D
,
9C–D
). It starts with weakly opisthocline axial ribs, which grade into three spiral rows of beads, with the suprasutural spiral row being most prominent. The whorl profile is almost flat-sided.A comparable sculpture is developed by ‘
C.’ filograna
Odhner, 1923
, which has a tripartite sculpture on early teleoconch whorls consisting of three beaded spiral cords of similar strength. These species are grouped herein as
mystica
-clade
‘
Clavatula’ bimarginata
(
Lamarck, 1822
) has a bipartite sculpture with a granulose subsutural cord and suprasutural spiral cord of equal strength with indistinct, bifid beads (
Fig 3F
,
9E–F
). The moderately concave interspace bears prominent, comma-shaped axial riblets formed by growth lines. Spiral threads form a somewhat cancellate pattern especially in the abapical half of the whorls. This species is placed in the
bimarginata
-clade.
‘Clavatula’ tripartita
(Weinkauff, 1876) (
Figs 10C–D
) and ‘
C
.’
taxea
(
Röding, 1798
) (
Fig. 10E
) are neither bipartite nor tripartite, but develop close-set spiral cords on flat-sided early teleoconch whorls. This morphology differs greatly from other
Clavatulidae
discussed herein and are placed herein in the
taxea
-clade. A separation of the ‘
C.
’
taxea-
clade from
Clavatula
is also suggested based on the comparatively slender, smooth and high spired shells, and the weak subsutural collar, which lacks spines. Consequently, already
Kilburn (1985: 424)
doubted that these South African species were congeneric with the western African
Clavatula
s.s.
In addition, the anal sinus allows for a separation of ‘
C
.’
mystica
, which has a moderately deep, widely V-shaped anal sinus, from
Clavatula muricata
and
C. rubrifasciata
, which have a deep, U-shaped anal sinus (
Fig. 5
). An additional
type
of early teleoconch sculpture is represented by the elongate biconic, prominently spinose ‘
C
.’
diadema
(
Kiener, 1839
) (
Figs 3C
,
9G
), which has weakly opisthocline axial ribs on the first teleoconch whorl and a weak subsutural spiral cord on the second teleoconch whorl. The beaded suprasutural spiral cord evolves from the abapical tips of the axial ribs on subsequent whorls. In addition, this species is characterized by very long spines.
Thus, within the species, formerly referred to as
Clavatula
we distinguish:
1.
Clavatula
(‘
C
.’
regia
,
‘
C
.’
muricata
,
‘
C
.’
rubrifasciata
,
‘
C
.’
lelieuri
)
2. caerulea
-clade (‘
C
.’
caerulea, ‘C.’
pyramidata
)
3.
mystica
-clade (‘
C
.’
mystica
)
4. bimarginata
-clade (‘
C
.’
bimarginata
)
5. taxea
-clade (‘
C
.’
taxea, ‘C.’ tripartita
)
6. diadema
-clade (‘
C
.’
diadema
)
As we focus on fossil species from the Neogene of Europe, we refrain from introducing genus names for these clades. Nevertheless, these data allow a refined systematic treatment of Paratethyan species, based on the hypothesis that early teleoconch sculpture is a useful trait to delimit genera within
Clavatulidae
. Only three of the Paratethyan
Clavatulidae
can be placed in one of these clades:
Clavatula sorini
nov. sp.
is placed in
Clavatula
s.s.
, ‘
C.
’
veronicae
Hoernes & Auinger, 1891
is placed in the
bimarginata
-clade and the ‘
Clavatula
’
interrupta
group and ‘
Clavatula
’
romana
(
Defrance, 1826
)
might be placed in the
mystica
-clade.
Consequently, most of the remaining Paratethyan species should be placed into new genera, which we propose in the following. Nevertheless, some species remain, which do not fit in our scheme. These are listed provisionally as ‘
Clavatula
’.
Distribution and stratigraphy.
The oldest records from the Eocene of
Italy
and
France
, placed in
Clavatula
by
Vinassa de Regny (1898)
and Boussac, (1911) represent other
Conoidea
families, such as
Pseudomelatomidae
or
Borsoniidae
(see
Vinassa de Regny 1898
, pl. 7 (20), figs 40–45).
Clavatula praegotica
Vinassa de Regny, 1898
is reminiscent of
Perrona
, but consists only of a fragment of the last whorl and lacks distinctive features (see
Vinassa de Regny, 1898
, pl. 7(20), figs 39a, b). Similarly, the numerous species from the Paleogene of
Kazakhstan
, placed in
Clavatula
by
Amitrov (1973)
are clearly not
Clavatulidae
and belong to other conoidean families (see
Amitrov 1973
, pls 9–11).
Species belonging to the ‘
Clavatula
’ species group first appear during the Oligocene.
Von Koenen (1890)
described ‘
Clavatula
’ species, such as ‘
Clavatula
’
barthi,
‘
C.’ bifrons
and ‘
C.’ roeveri
, from the Rupelian of the North Sea. Several North Sea species such as ‘
Clavatula
’
struckmanni
and ‘
C.’ millegranosa
, however, are clearly unrelated to
Clavatula
based on their morphologies (see
von Koenen 1890
, pl. 33, figs 8, 12). Similarly, ‘
Clavatula
’
mogenstrupensis
Schnetler in
Schnetler & Beyer, 1990
, from the Chattian of
Denmark
, is unrelated to
Clavatula
based on its convex whorls and broad axial ribs (see
Schnetler & Beyer 1990
, pl. 3 fig. 5). ‘
Clavatula
’
apenninica
Bellardi, 1877
, from the Rupelian of
Italy
, seems to represent a
Clavatulidae
, but does not fit in
Clavatula
due to its comparatively slender biconic shell with high last whorl and weak subsutural collar (see
Ferrero Mortara
et al
. 1981:77
, pl. 15, figs 1a–b).
During the Chattian, the ‘
Clavatula
’ species group was widespread along European coasts, documented from the northeastern Atlantic [‘
Clavatula
’
concatenata
(
Grateloup, 1832
)
] and the Central Paratethys Sea (‘
Clavatula
’
danuvii
Vicián, Kovács & Stein, 2019
) (
Lozouet 2017
;
Vicián
et al.
2019
). The North Sea species
Clavatula chattica
R.
Janssen, 1978
differs from
Clavatula
in having convex whorls and axial ribs (see R.
Janssen 1978
).
Species from the Miocene of the Western Atlantic, placed by
Gabb (1873)
and
Gardner (1947)
in
Clavatula
, are clearly unrelated with
Clavatulidae
and represent rather members of the
Pseudomelatomidae
or other
Conoidea
families. Similarly, ‘
Clavatula
’ species described from the Neogene of the Indo-West Pacific, by
Cox (1936)
,
Oostingh (1938)
and
Beets (1941
,
1942
) represent other genera such as
Paradrillia
and
Turricula
.
Therefore, the ‘
Clavatula
’ genus group is strictly Tethyan. It was widely distributed along the European Atlantic and Proto-Mediterranean coasts during the Oligocene. The group peaked in distribution and diversity during the Miocene, documented by numerous species from all European biogeographic regions except for the Eastern Paratethys (e.g.,
Bellardi 1877
;
Kautsky 1925
;
Glibert 1954
;
Peyrot 1931
;
Landau
et al
. 2013
,
2020
;
hoc opus
).
After the late Pliocene cooling event, the group suffered a gradual range contraction, and today
Clavatula
and other ‘
Clavatula
’-clades are restricted to tropical waters off West Africa, where they are represented by a relatively small number of genus groups and species compared to their older historical diversity.