Conus exiguus
(Eichwald, 1830)
Conus eichwaldi
(Harzhauser & Landau, 2016)
Conilithes eichwaldi nov. nom. is proposed as new name for
Conus exiguus (Eichwald, 1830) [non Lamarck, 1810].
Descrizione e caratteristiche (1):
Syntypes: Two potential syntypes are stored in the Zoological
Museum of St. Petersburg (Russia); inventory number ZISP 62085.
Type locality. Eichwald (1830) mentioned Bilozirka (= Bialazurka,
Bialozurka) and Shushkivtsi (=Shukowze) as type localities but on the label of
the available specimens the locality is given as Zalisce. Therefore, it is
unclear if these specimens are syntypes. In any case, all localities are
located within a small area about 50 km NE of Ternopil (Ukraine).
Age: Middle Miocene, Badenian
(Langhian or Serravallian).
Etymology. Referring to the Russian
palaeontologist Karl Eduard von Eichwald (1795–1876), who was a pioneer in
geosciences in the Carpathian Foredeep.
Description. Small strombiform shells with high spire; teleoconch
consisting of at least 9 whorls; spire gradate to scalariform with beaded
carina placed mid-whorl or close to the lower suture; sutural ramp faintly
striate. Shoulder broadly rounded, weakly subangulate; position of maximum
diameter below shoulder; shoulder striate; subsutural flexure unknown. Last
whorl stout, concave below maximum diameter, constricted; lower third of last
whorl with sharp spiral cords; siphonal fasciole indistinct. Aperture largely
missing in both specimens. Shell
measurements and ratios. 2 specimens are available: SL: 15 mm, MD: 7 mm, spire
angle: 60°, last whorl angle: 33°; SL: 11 mm, MD: 6 mm, spire angle: 70°, last
whorl angle: 40°
Discussion. This species is unique among Paratethyan cones for its
high spire and rounded shoulder, resulting in a strombiform profile. It is
reminiscent of Plagioconus
burdigalensis (Mayer, 1858), from the
Burdigalian of the Aquitaine Basin, which also has a gradate to scalariform
spire with carina and a last whorl with a broadly rounded, weakly subangulate
shoulder and prominent spiral cords on the base. It differs from C. eichwaldi in its larger size and elongate last whorl. Therefore, it is unlikely
that the Polish species is just a juvenile Plagioconus burdigalensis.
The high spire, ventricose last whorl and striate
sutural ramp would also fit in Lautoconus but the tuberculate and
scalariform spire outline, are rather untypical for this genus (although Lautoconus
desidiosus (Adams, 1854) may form a scalariform spire). Therefore, we
tentatively place this species in Conilithes. Eichwald (1830) described
this small and rare species as Conus exiguus. This name was already
preoccupied by the Recent Conus exiguus (Lamarck, 1810) from New
Caledonia. Therefore, we propose Conilithes eichwaldi as replacement
name.
Paleoenvironment. Unknown; other specimens
from the localities mentioned by Eichwald (1839, 1853) are typical nearshore
taxa.
Distribution in Paratethys. Badenian
(middle Miocene): Carpathian Foredeep: Zalisce, Bilozirka (= Bialazurka,
Bialozurka) and Shushkivtsi (= Shukowze) (Ukraine)
|
|
|
|
Conus eichwaldi (1) B1–B2. Conilithes eichwaldi nov. nom., Zalisce (Ukraine),
ZISP 62085. C1–C2. Conilithes
eichwaldi nov. nom., Zalisce (Ukraine), ZISP 62085. |
Conus arntzenii (Martin, 1916) RGM.784.937 - Java |
|
|
|
|
Conus exiguus (Eichwald,
1830) Plate IX - Fig.4 |
|
Bibliografia Consultata