An overlooked diversity-the Costellariidae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea
Author
Harzhauser, Mathias
0000-0002-4471-6655
mathias.harzhauser@nhm-wien.ac.at
Author
Landau, Bernard
0000-0002-4471-6655
mathias.harzhauser@nhm-wien.ac.at
text
Zootaxa
2021
2021-06-09
4982
1
1
70
journal article
5925
10.11646/zootaxa.4982.1.1
f68b381d-d0dd-44e2-b9fe-6cf3c1aab1fa
1175-5326
4921842
58388FB8-128A-4381-83D1-3C508D0D3873
Bellardithala kovaci
nov. sp.
Figs 4C
,
6D
1
–D
2
, E
1
–E
2
, F
1
–F
2
, G
1
–G
2
, H
1
–H
2
, I
1
–I
2
[
Mitra
]
candidula
[Partsch]—
Hörnes 1848: 17
[
nomen nudum
].
Mitra obsoleta
Bronn
[sic]—
Hörnes 1852b: 110
, pl. 10, figs 32a–b [
non
Voluta obsoleta
Brocchi, 1814
].
[
Mitra
]
obsoleta
Brocc.
—
Auinger 1871: 8
[
non
Brocchi, 1814
].
[
Callithea
]
obsoleta
Brocc.
—Hoernes 1880: 125 [
non
Brocchi, 1814
].
Mitra obsoleta
Brocc.
—
Hoernes & Auinger 1880: 88
[
non
Brocchi, 1814
].
Mitra obsoleta
Braun.
—
Rzehak 1894: 256
[
non
Brocchi, 1814
].
Thala obsoleta
Brocch.
—
Meznerics 1933: 344
[
non
Brocchi, 1814
].
Vexillum
(
Costellaria
)
obsoletum
(Brocc.)
—
Sieber 1956: 244
[
non
Brocchi, 1814
].
Th
[
ala
].
obsoleta
(Brocchi)
—
Sieber 1958a: 153
[
non
Brocchi, 1814
].
Thala obsoleta
(Brocc.)
—
Sieber 1958b: 149
[
non
Brocchi, 1814
].
Thala obsoleta
(
Brocchi, 1814
)
—
Bałuk 1997: 39
, pl. 11, fig. 2 [
non
Brocchi, 1814
].
Type material.
Holotype
:
NHMW 1846
/0037/0114, SL:
8.3 mm
, MD:
3.1 mm
,
Steinebrunn
(
Austria
), illustrated in
Hörnes (1852b
, pl. 10, figs 32a–b), figs 6D
1
–D
2
.
Paratypes
:
NHMW 1858
/0047/0007, SL:
8.9 mm
, MD:
3.3 mm
,
Sedlec
(=
Porzteich
) (
Czech Republic
), figs 6E
1
–E
2
;
NHMW 1866
/0001/1019, SL:
6.8 mm
, MD:
2.7 mm
,
Forchtenau
(
Austria
), figs 6F
1
–F
2
;
NHMW 1871
/0010/0331, SL: 6.0 mm, MD:
2.2 mm
,
Steinebrunn
(
Austria
), figs 4C, 6G
1
–G
2
;
NHMW 1871
/0011/0004, SL:
5.9 mm
, MD:
2.2 mm
,
Steinebrunn
(
Austria
), figs 6H
1
–H
2
.
Additional material.
NHMW 2020
/0062/0001, SL:
5.7 mm
, MD:
2.1 mm
,
Steinebrunn
(
Austria
), figs 6I
1
–I
2
.
18 specimens
NHMW 2020
/0062/0002, all
Steinebrunn
(
Austria
)
.
Type
locality.
Steinebrunn
(
Austria
)
.
Type
stratum.
Silty sand of the Baden Formation.
Age.
Middle Miocene, Badenian (Langhian).
Etymology.
In honour of Michal Kováč (Comenius University, Bratislava,
Slovakia
), in recognition of his contributions on the stratigraphy and paleogeography of the Paratethys Sea.
Diagnosis.
Medium-sized, moderately slender fusiform shell differing from other
Bellardithala
species
by its weak spiral sculpture and broad flat axial ribs separated by very narrow interspaces.
Description.
Shell medium-sized, moderately slender fusiform with slightly cyrtoconoid spire. Protoconch (fig. 4C) high conical of 3.5 weakly convex whorls; height: 660 μm, diameter: 580 μm. Teleoconch of moderately convex 5.5 whorls with periphery slightly below mid-whorl; suture narrowly incised. Last whorl high, weakly convex with weak basal constriction. Sculpture of first teleoconch whorl of broad, slightly opisthocline axial ribs with flattened tops separated by narrow interspaces. Spiral sculpture reduced to five spiral threads in axial interspaces. Axial ribs becoming broad and low on later spire whorls with irregularly spaced narrow interspaces. Spiral threads restricted to axial interspaces causing tiny pits between axial and spiral elements. Interspaces very narrow, present throughout growth. Spiral grooves somewhat stronger in adapical third of last whorl causing tiny pits at intersections with axial interspaces. Axial sculpture weakening towards fasciole. Aperture elongate, moderately narrow with distinct, narrow anal sinus. Inner lip narrow, indistinct. Columella with four broad folds, adapical two most prominent. Outer lip thickened with 10 denticles on inner side. Siphonal canal moderately short, moderately wide, straight with shallow siphonal notch.
Shell measurements and ratios
. NHMW specimens: SL:
6.8–8.5 mm
, MD:
2.7–3.3 mm
; AA: 44–46°, SL/ MD: 2.8, AL/AW: 4.7–5.3, AH/S: 2.4–2.6.
Remarks.
Bellardithala kovaci
is documented also by subadult specimens (figs 6G
1
–G
2
, H
1
–H
2
) illustrating the development of denticles in juveniles, which was also observed in
B. partschi
by
Rosenberg & Salisbury (2003)
.
This species was misidentified so far as
Bellardithala obsoleta
(
Brocchi, 1814
)
, which was originally described from the Italian Pliocene. The
holotype
of
Voluta obsoleta
Brocchi, 1814
, illustrated in Rossi Ronchetti (1955) and
Pinna & Spezia (1978)
, differs clearly from the Paratethyan species in having prominent axial sculpture, on spire whorls and last whorl. Pliocene specimens of
B. obsoleta
from Altavilla (
Italy
), described by
Giannuzzi-Savelli & Reina (1983)
, differ from the Paratethyan species also in the more prominent axial and spiral sculpture and have a more slender fusiform outline. Serravallian specimens from the
Karaman
Basin in
Turkey
, described by
Landau
et al
. (2013)
as
Thala obsoleta
, differ from the Paratethyan species clearly in the prominent axial ribs and the subcylindrical spire whorls. The same features distinguish Tortonian specimens from Montegibbio in
Italy
from
Bellardithala kovaci
(see
Davoli, 2000
).
Bellardithala boehmi
(
Boettger, 1906
)
differs in its more slender fusiform outline, much more prominent axial and spiral sculpture on the early teleoconch whorls, and the lower aperture/spire ratio (0.9 versus 1.1).
Palaeoenvironment.
Coastal, inner neritic. The assemblage from Steinebrunn suggests shallow sublittoral environments with sea grass (
Harzhauser & Landau 2019
).At the Niederleis section, sediment and fossils from coastal and lagoonal environments not exceeding
30 m
water depth were transported by tempestites into offshore settings (
Mandic
et al
. 2002
).
Distribution in Central Paratethys.
Badenian (middle Miocene):
North Alpine-Carpathian Foreland Basin
: Unkovice (
Czech Republic
) (
Rzehak 1894
);
Korytnica Basin
: Korytnica (
Poland
) (
Bałuk 1997
);
Vienna
Basin
: Niederleis, Steinebrunn (
Austria
); Mikulov, Sedlec (= Porzteich) (
Czech Republic
) (
Hoernes & Auinger 1880
);
Eisenstadt-Sopron Basin
: Forchtenau (
Austria
) (
Sieber 1956
).