Two morphologically close new species of Gibbula

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Bollettino della Società Paleontologica Italiana, 48 (1), 2009, 33-40. Modena, 15 maggio 2009
Two morphologically close new species of Gibbula (Archeogastropoda:
Trochidae) from the Pleistocene of Sicily and Peloponnesus
Vittorio GARILLI
V. Garilli, APEMA Research and Educational Service, Via Alla Falconara 34, I-90136 Palermo, Italy; [email protected]
KEY WORDS - Trochidae, Gibbula, New species, Mediterranean, Pleistocene.
ABSTRACT - Two gastropod species of the genus Gibbula Risso, 1826, G. mariaeangelae n. sp. and G. marialuisae n. sp., are
described from the Middle-Upper Pleistocene of Kyllini (NW Peloponnesus) and the Lower Pleistocene of Cartiera Mulino (SE Sicily)
respectively. These species are morphologically similar to each other and well distinguishable from congeners, being characterized by
a widely umbilicated, quite depressed shell with an almost keeled periphery. They mainly differ in having different patterns of sculpture
and preserved coloration: G. marialuisae n. sp., which also has a more depressed shell shape, shows a more delicate spiral sculpture
and a color pattern consisting of pale reddish lines and spots on a whitish background, whereas G. mariaeangelae is characterized by
whitish-cream spiral cords on a reddish background. This further description of two new Gibbula species, after that of G. olympica
Garilli, Crisci & Messina, 2005 (from Kyllini), significantly contributes to a more detailed knowledge of the genus Gibbula in the
Mediterranean Pleistocene. Both the described species lived in a palaeoenvironment linked to the present Posidonia oceanica biocoenosis.
RIASSUNTO - [Due nuove specie morfologicamente affini di Gibbula (Archeogastropoda: Trochidae) dal Pleistocene della Sicilia e
del Peloponneso] - Vengono presentate due nuove specie di Gibbula Risso, 1826, G. mariaeangelae n. sp. e G. marialuisae n. sp.,
rispettivamente dal Pleistocene medio-superiore di Kyllini (Peloponneso nord-ovest) e dal Pleistocene inferiore di Cartiera Mulino
(Vittoria, Sicilia sud-occidentale). La descrizione di tali specie, dopo quella di G. olympica Garilli, Crisci & Messina, 2005 (dal deposito
di Kyllini), fornisce un ulteriore contributo alla conoscenza dettagliata del genere Gibbula del Pleistocene Mediterraneo. Le nuove specie
qui descritte appaiono conchiologicamente affini e facilmente riconoscibili dalle congeneri, avendo una caratteristica conchiglia
particolarmente depressa e provvista di ampio ombelico. Esse si differenziano principalmente per avere colorazione e scultura
differenti: G. marialuisae n. sp. presenta una scultura spirale più delicata ed una colorazione di linee rossicce su un fondo biancastro,
mentre G. mariaeangelae n. sp. ha cordoncini spirali bianco crema su un fondo rossiccio. Peraltro, G. marialuisae n. sp. possiede una
conchiglia più depressa. G. mariaeangelae n. sp. è stata confrontata con alcune congeneri con le quali mostra, in generale, lievi affinità,
inadatte a chiarire eventuali relazioni filogenetiche. In modo particolare, sono stati effettuati confronti tra G. mariaeangelae n. sp., G.
ardens (Von Salis, 1793) e G. umbilicaris (Linnaeus, 1767) (con specifico riguardo ad alcune varietà), affini esclusivamente per il
modello di colorazione, la scultura della teleoconca e, relativamente a G. umbilicaris, per lo sviluppo ombelicale. G. marialuisae n. sp.
è invece difficilmente confrontabile con altre congeneri note, ad eccezione di G. joubini Dautzenberg, 1910 (Africa occidentale) con la
quale condivide esclusivamente il tipo di colorazione. Vengono inoltre fornite alcune informazioni di carattere paleoecologico sulle
specie descritte, le quali vissero in paleoambienti legati a quelli attuali delle praterie di Posidonia oceanica.
INTRODUCTION
Within the Mediterranean fossil and Recent
archeogastropods, the genus Gibbula Risso, 1826
represents a common malacological component,
especially in shallow water assemblages from vegetated
bottoms. It certainly is one of the most diversified group
in the family Trochidae, as slightly more than 20 species
were recorded from the Mediterranean Sea (GiannuzziSavelli, 1997), where some endemisms also occur (e.g.
G. nivosa Adams A., 1851, from Malta, G. spratti (Forbes,
1844), from the Aegean Sea, and G. tingitana Pallary,
1901, from the Alboran Sea). Almost the same number
of species occurred in the Upper Neogene shallow water
mollusc-rich associations from Tuscany (N Italy, see
Chirli, 2004), whereas fewer species are recorded from
the Mediterranean Pleistocene, probably because of the
lack of exhaustive taxonomic revisions. As a matter of
fact, due to the wide intraspecific range shown by its
species, this genus is affected by somewhat unresolved
systematic-taxonomic matter. Also the phylogenetic
relationships between its fossil and Recent
representatives appear to be rather enigmatic.
ISSN 0375-7633
The main aim of the present article is to discuss and
describe two interesting Gibbula species, recovered
from the Pleistocene deposits of Cartiera Mulino
(Vittoria, SE Sicily, Italy) and Kyllini (NW Peloponnesus,
Greece), considering them to be new taxa after an
extensive check of the malacological works illustrating
and/or discussing the family Trochidae from various
geographical realms (e.g. Bucquoy et al., 1884; Pilsbry,
1889; Sacco, 1896; Cossmann & Peyrot, 1918;
Malatesta, 1960; Nordsieck, 1968; Ghisotti & Melone,
1972; Malatesta, 1974; Caprotti, 1976; Nordsieck &
García-Talavera, 1979; Spadini, 1986, 1987; Cavallo &
Repetto, 1992; Beck, 1995; Giannuzzi-Savelli et al.,
1997; Borghi & Vecchi, 2001; Delamotte & VardalaTheodorou, 2001; Ardovini & Cossignani, 2004; Chirli,
2004).
METHODS, MATERIALS AND GEOLOGICAL
SETTING
Two shells were picked from bulk samples (about 70
dm3), collected at the top of a regressive marine Lower
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Bollettino della Società Paleontologica Italiana, 48 (1), 2009
Fig. 1 - General (a) and detailed locations of the Kyllini-Cape Trypiti
N2 layer (b) and the Cartiera Mulino deposit (c, asterisk). KY =
Kyllini; TR = Cape Trypiti; VI = Vittoria. Figs. 1a and 1b are modified
from Garilli et al. (2005).
the “Kyllini field-work 2004” from a large amount
(about 80 dm3) of sediment, sampled from the N2 layer
described by Garilli et al. (2005). As reported by these
authors, this stratigraphical layer can be referred to the
Middle-Upper Pleistocene, lying 50-70 m over a greyish
blue turritellid-rich layer with a late Sicilian (sensu
Ruggieri et al., 1984) - early Middle Pleistocene
nannofossil association, namely Crenalithus asanoi
(Sato & Katayama, 1992) and Gephyrocapsa sp. 3
(Castradori, 1993; Sprovieri, 1993; Di Stefano, 1998;
De Kaenel, 1999). The N2 layer, containing leaves and
rhizomes of Posidonia oceanica and a molluscan
association dominated by herbivorous - detritus feeding
taxa (mainly trochids, phasianellids, cerithiids and
rissoids), was referred to the HP biocoenosis by Garilli
et al. (2005; see also this article for a stratigraphical
log containing the N2 layer).
In order to describe the two new species, particular
attention has been given to teleoconch features. Scanning
electronic microscope analyses, addressed to an in-depth
investigation of protoconch characters, were not
performed in order to preserve the original coloration
occurring in the investigated material. However, a simple
description of larval shells has been provided by
stereomicroscope observation.
The following abbreviations are used for
measurements: Ht = shell height; Hlw = last whorl height;
Ha = aperture height; D = shell maximum diameter; Ilw
= inclination of whorl profile to shell axis (measured on
the last whorl). The type material was measured with
precision of 0.05 mm. A schematic drawing of
measured characters is given in Fig. 2. Studied material
is housed in the Dipartimento di Geologia e Geodesia,
University of Palermo, Italy (DGUP, V. Garilli Coll.)
and in the Goulandris Natural History Museum, Kifissia,
Greece (GNHM).
SYSTEMATICS
Class GASTROPODA
Family TROCHIDAE Rafinesque, 1815
Pleistocene sequence (Conti et al., 1979; Costa, 1989)
underlying a lacustrine succession. This deposit crops
out at about one hundred meters from the abandoned
paper-mill named Cartiera Mulino (Vittoria, SE Sicily,
Figs. 1a, c). In particular, material comes from the “3D1”
layer of Costa (1989), of which the very rich mollusc
association is related to shallow, sheltered muddy-sandy
environments with Posidonia oceanica (Linnaeus)
Delile, 1813, namely a SVMC-HP (sensu Pérès & Picard,
1964) ecotone (Costa, 1989). This layer consists of a
greyish to yellowish clayey fine sand containing a
molluscan assemblage dominated by trochids (mainly
Jujubinus spp.), rissoids (mainly Pusillina spp. and
Alvania spp.), and cerithiids (mainly Bittium spp.) (see
Costa, 1989 for a comprehensive account of the
molluscan association from the 3D1 layer and the related
stratigraphic log).
Four further shells come from the northern part of
the Kyllini-Cape Trypiti sequence (Kyllini, Ileia, NW
Peloponnesus, Figs. 1a-b). They were collected during
Genus Gibbula Risso, 1826 ex Leach ms.
Type species: Trochus magus Linnaeus, 1758 (S.D.,
Herrmannsen, 1847)
Gibbula mariaeangelae n. sp.
Pl. 1, figs. 7-12
Description - Shell small, depressed, conical,
reaching about 4.6 mm and 8.3 mm in height and diameter
respectively. Protoconch depressed and paucispiral,
consisting of slightly more than one whorl starting with
roughly triangular nucleus. Whorls apparently smooth,
separated from teleoconch by very weak demarcation.
Teleoconch growing more in width than in height, Ht/D
ratio from 0.55 (holotype) to 0.62 (paratype 1),
consisting of about 4 (holotype) and 3.5 (paratype 1)
slightly convex whorls with very short, almost
horizontal subsutural ramp and Ilw of about 50°. Whorls
V. Garilli - New Mediterranean Pleistocene taxa of Gibbula
35
Type material and locality - Holotype (GNHM FA
ID 19/22), paratypes 1 (DGUP KIGR 005), 2 (DGUP
KIGR 006) and 3 (DGUP KIGR 007) are from the
Middle-Upper Pleistocene layer N2 of Kyllini, Ileia, NW
Peloponnesus, Greece (UTM 34S 511793E 4199216N).
Etymology - This species is dedicated to Maria Angela
Stradi, a lovely friend of mine.
Occurrence - Gibbula mariaeangelae n. sp. is known
only from type material. Accordingly, it is only known
from the Middle-Upper Pleistocene of Kyllini, Ileia, NW
Peloponnesus. The paleoenvironmental setting indicates
that the species lived in Posidonia oceanica meadows.
Fig. 2 - Measurements. Ht = shell height; Hlw = last whorl height;
Ha = aperture height; D = shell maximum diameter; Ilw = inclination
of whorl profile to shell axis.
separated by deep, almost horizontal suture. Early
whorls more convex and rounded, smooth, with mottles
variable in size and shape. Rest of shell sculptured by
primary and secondary spiral cords. Primary cords
narrow and distinct, numbering 8 on last whorl; two
stronger cords on subsutural part and on periphery of
last whorl. Secondary cords very narrow, irregular and
almost flat, numbering 4 (holotype) to 2 (paratype 1)
on last whorl. Primary cords separated by wide
interspaces, where secondary cords occur in middle.
Very fine, narrowly interspaced spiral threads, mainly
observed on adapical portion of mature whorls, in
interspaces between primary and secondary sculpture.
Whorls covered by numerous, marked, prosocline
incremental lines, reaching from suture to suture,
obsolete on spiral cords. Base moderately convex with
sculpture pattern similar to the dorsal one, having 7
(holotype) and 6 (paratype 1) spiral, widely interspaced,
primary cords, and 3 (holotype) and 2 (paratype 1)
narrower, spiral secondary cords. Umbilicus wide,
notably deep, bordered by two spiral cords. Cords
crossed by well defined incremental scars, well marked
on remaining basal area. Last whorl well developed,
making up 83% (paratype 1) to 86% (holotype) of entire
shell height, almost keeled at periphery. Aperture wide,
subrhomboidal, making up 59% (paratype 1) to 62%
(holotype) and 71% (paratype 1) to 73% (holotype) of
last whorl and total height respectively. Outer lip
rounded, thin, internally smooth and thickened close
to edge. Columellar side sinuous in central-upper part
and slightly thickened abapically. Original coloration well
preserved especially on holotype and paratype 1. Spiral
cords whitish-cream, white on stronger subsutural and
peripheral cords; background bright red, all through
shell surface.
Measurements - Holotype: Ht = 4.6 mm; Hlw = 3.95
mm; Ha = 2.85 mm; D = 8.3 mm Paratype 1: Ht = 4.15
mm; Hlw = 3.45 mm; Ha = 2.45 mm; D = 6.7 mm.
Paratypes 2 and 3: not measured because of their bad
preservation.
Comparisons and remarks - Gibbula mariaeangelae
n. sp. is somewhat similar to juvenile shells of G. pennanti
(Philippi, 1846) (see Beck, 1995, pl. 15, figs. 9-10) from
which it differs mainly by having a more depressed shell
with a proportionally larger umbilicus. Furthermore, G.
pennanti has a larger, markedly elongated adult shell
(mean Ht/D of 0.9) with early teleoconch whorls showing
flat, wider spiral cords, separated by narrower interspaces
(see Beck, 1995, pl. 102, figs. 1-2).
Gibbula leucophaea (Philippi, 1836), as illustrated
by Beck (1995, pl. 16), may have a depressed shell (Ht/
D down to about 0.7, see Beck, 1995, pl. 16), with a
similar, acute periphery of the last whorl. However, this
species has more convex whorls, with a less inclined
profile to the shell axis; it also has more prominent spiral
cords, appearing markedly elongated (usually with an Ht/
D of about 0.95) and stepped (see Beck, 1995, pl. 99,
fig. 3).
Gibbula umbilicaris (Linnaeus, 1767), particularly
its depressed form “latior” (originally as Trochus latior
Monterosato, 1878; see Giannuzzi-Savelli et al., 1997,
figs. 242a-b and 243) is comparable to G. mariaeangelae
n. sp. Color pattern (whitish suprasutural maculae on a
reddish background), sculpture (alternating primary and
secondary spiral cords) and umbilicus shape are the most
remarkable shared characters. G. umbilicaris differs by
having a larger shell and more convex and proportionally
higher whorls, with a more elevated (Ht/D 0.7-0.9) and
stepped profile. Furthermore, in G. umbilicaris the spiral
sculpture, starting from the first teleoconch whorls, is
finer, more irregular in thickness, and with fewer primary
spiral cords on the last whorl. Also the shell base of the
form “latior” is different, being less convex (see Beck,
1995 pl. 25, fig. 4).
Gibbula ardens (Von Salis, 1793), which is similar
to G. umbilicaris (see also Beck, 1995), is comparable
with G. mariaeangelae n. sp. as well. G. ardens form
“barbara” (reported by Monterosato, 1884 as G.
barbara), from the Pleistocene (Ruggieri, 1978) of
Timpone Pelato (W Sicily), has a quite similar color
pattern, with whitish spots, usually particularly marked
on the subsutural spiral cords and close to the base, on a
reddish background (Figs. 3a-c). The sculpture, with
primary and secondary spiral cords, is very similar to that
of the new species. However, the shell of G. ardens is
larger (maximum height 18.5 mm in the examined
specimens), more elevated (Ht/D 0.8-1.05), with a
proportionally narrower umbilicus and more rounded
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Bollettino della Società Paleontologica Italiana, 48 (1), 2009
whorls, and (in the examined form “barbara”) the
secondary spiral cords lie closer to the primary sculpture.
Furthermore, the shell base of the form “barbara” bears
flat, more closely spaced spiral cords. It is noteworthy
to remark that G. ardens co-occurs with the new species
in the N2 layer where it shows differences from G.
mariaeangelae n. sp. similar to those described above
for the form barbara (see Fig. 3d). G. ardens var.
succincta Monterosato, 1878 (as Trochus succinctus),
see Bucquoy et al. (1884, pl. 45, figs. 13-16) and Pilsbry
(1889, pl. 33, figs. 82-83), has a rather depressed shell
and differs from G. mariaeangelae n. sp. mainly by having
more marked spiral cords, a very rounded last whorl
profile and a markedly canaliculated suture.
Other Gibbula species from the N2 layer, G. magus
(Linnaeus, 1758), G. fanulum (Gmelin, 1791), G.
adansoni (Payraudeau, 1826) and G. olympica Garilli,
Crisci & Messina, 2005, are not particularly similar to
G. mariaeangelae n. sp. Rather, the new species is
conchologically close to another new species herein
described below.
It is noteworthy that the Gibbula species compared
above have a higher Ht/D ratio ranging from 0.7 to 1.05,
a range characterizing most of the congeners from the
Mediterranean Upper Neogene to Recent. Very few
exceptions do exist, e.g. the Pliocene G. distefanoi
Crema, 1903, with an Ht/D (down to 0.56) matching that
of G. mariaeangelae n. sp. The two species are otherwise
not similar.
G. mariaeangelae n. sp. also shows a certain amount
of ontogenetic variation, the smaller shells (paratypes)
having more convex whorls and a slightly less depressed
general shape than larger ones.
The main protoconch characters, namely its depressed
shape, its apparently smooth surface and the roughly
triangular nucleus, are frequent within Gibbula as well
as in other trochid genera (see Beck, 1995). Also the
onset of teleoconch sculpture, which is rather similar to
that shown by G. umbilicaris (see Beck, 1995, pl. 100,
fig. 8) is a character shared with different trochids (e.g.
the genus Osilinus Philippi, 1847, see Beck, 1995, pl.
103, fig. 8 and pl. 104, figs. 1 and 6).
Gibbula marialuisae n. sp.
Pl. 1, figs. 1-6
Description - Shell small, strongly depressed,
conical, reaching 3.5 mm and about 6.9 mm in height
and width respectively. Protoconch (preserved on
holotype only) depressed and paucispiral, probably
consisting of about 1 apparently smooth whorl, with a
nearly triangular nucleus. Protoconch/teleoconch
transition not well marked. Teleoconch of 3.7 (holotype)
and about 3 (paratype) whorls growing more rapidly
in width than in height, having a Ht/D ratio of 0.48
(paratype) and 0.51 (holotype). Whorls slightly convex
(almost flat in paratype), smooth near teleoconch onset,
then with narrow spiral cords separated by wide
interspaces; Ilw is about 56° and 62° in holotype and
paratype respectively. Spiral cords not always regular
in width; 10 cords (holotype) and 8 cords (paratype)
on last whorl. Cords lacking from early teleoconch
whorls, which appear smooth. Rest of shell with
prosocline growth lines extending from suture to suture.
Last whorl acute at periphery and well developed,
making up about 90% total height. Teleoconch whorls
separated by deep, almost horizontal suture. Base
moderately convex, sculptured by 11 (holotype) and 8
(paratype) spiral cords and growth lines. Umbilicus very
wide and deep, with marked incremental scars and welldefined, almost keeled periphery. Aperture wide, nearly
rhomboidal, making up 67% (paratype) to 68%
(holotype) and 77% (paratype) to 78% (holotype) of
last whorl and total height respectively. Outer lip thin,
internally smooth; columellar lip gently arched, with
slight thickening in lower part. Original coloration well
preserved: reddish lines or spots (well marked on
adapical portion of teleoconch whorls of holotype) on
spiral cords on whitish-cream background. Very early
teleoconch whorls white (in holotype) or translucent
(in paratype). Base with almost identical coloration as
dorsum, having reddish lines (near periphery) and spots
(covering most of base) on spiral cords.
Measurements - Holotype: Ht = 3.5 mm; Hlw = 3.05
mm; Ha = 2.35 mm; D = 6.85 mm Paratype: Ht = 2.5
mm; Hlw = 2.2 mm; Ha = 1.7 mm; D = 5.15 mm.
Type material and locality - Holotype (DGUP CMRG
003) and paratype (DGUP CMRG 004), are from the
Lower Pleistocene 3D1 layer (described by Costa, 1989)
of Cartiera Mulino (UTM 33S 461624E 4089386.7N),
about 15 km WNW of Ragusa, SE Sicily.
Etymology - This species is dedicated to my mother
Marialuisa.
Occurrence - Gibbula marialuisae n. sp. is known
only from the type locality. The paleoenvironmental
EXPLANATION OF PLATE 1
figs. 1-6
- Shells of Gibbula marialuisae n. sp. Lower Pleistocene, 3D1 layer of Cartiera Mulino (SE Sicily).
1-3 - Apertural, apical and basal views of holotype (Ht = 3.5 mm, D = 6.85 mm, DGUP, CMRG 003).
4-6 - Apertural, apical and basal views of paratype (Ht = 2.5 mm, D = 5.15 mm, DGUP, CMRG 004).
figs. 7-12
- Shells of G. mariaeangelae n. sp. Middle-Upper Pleistocene N2 layer of Kyllini (NW Peloponnesus, Greece).
7-9 - Apertural, apical and basal views of paratype 1 (Ht = 4.15 mm, D = 6.7 mm, DGUP, KIGR 005).
10-12- Apertural, apical and basal views of holotype (Ht = 4.6 mm, D = 8.3 mm, GNHN, FA ID 19/22).
All to scale.
V. Garilli - New Mediterranean Pleistocene taxa of Gibbula
Pl.371
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Bollettino della Società Paleontologica Italiana, 48 (1), 2009
setting inferred for the 3D1 layer at the Cartiera Mulino
site indicates that the species lived on sheltered shallowwater bottoms with Posidonia oceanica.
Comparisons and remarks - Gibbula marialuisae n.
sp. shares remarkable similarities only with G.
mariaeangelae n. sp.: the two species have a very
depressed shell, with a wide, deep umbilicus, bordered
by a sort of keel, and a sculptural teleoconch pattern
formed by narrow spiral cords. However, G.
mariaeangelae n. sp. has a less depressed shell, almost
keeled at the periphery of the last whorl, a less inclined
whorls profile (50° vs. 56-62° to the shell axis), and bears
more distinct spiral sculpture consisting of primary and
secondary cords. Furthermore very fine spiral threads
occur in the interspaces between primary and secondary
cords of G. mariaeangelae n. sp. The coloration of the
two species is also different, consisting of a reddish
background with whitish spiral lines in G. mariaeangelae
n. sp., and of a whitish background with reddish-orange
lines or spots in G. marialuisae n. sp. The coloration
pattern of the latter species, never found in European
congeners, is comparable to that of the West African
species G. joubini Dautzenberg, 1910, which may have
brownish linear maculae or lines on the spiral sculpture.
However, the eastern Atlantic species has a larger, quite
elevated shell (Ht/D 0.9-1.06), with a proportionally
narrower umbilicus and stronger and flatter spiral cords
starting from the first teleoconch whorl (Beck, 1995, pl.
12, figs. 1-11 and pl. 102, figs. 7-8).
Probably due to ontogenetic changes, the smallest
shell of Gibbula marialuisae n. sp. (paratype) has less
convex whorls, a more acute last whorl periphery and a
more inclined whorls profile (about 62° vs. 56°) than
the respective holotype. The protoconch characters and
the early teleoconch sculpture of G. marialuisae n. sp.
are very similar to those of G. mariaeangelae n. sp.
and, apparently, do not provide distinguishing
characters.
CONCLUDING REMARKS
Gibbula mariaeangelae n. sp. and G. marialuisae n.
sp. are morphologically close species sharing remarkable
characters: teleoconch sculpture, umbilicus shape and,
above all, a very depressed shell (with a Ht/D range of
about 0.5-0.6). The last character is very rarely shared
with other congeners (e.g. the Pliocene G. distefanoi),
as the mean Ht/D of Gibbula is about 0.9, and its wide
Fig. 3 - Gibbula ardens (Von Salis, 1793), with morphs showing
coloration pattern and sculpture comparable to those of G.
mariaeangelae n. sp.
a-c - Juvenile shell of the form barbara Monterosato, 1884 with
size comparable to that shown by G. mariaeangelae n. sp. (a,
apertural; b, basal; c, apical views), Ht = 9.3 mm, D = 10.1 mm,
Pleistocene of Timpone Pelato (W Sicily).
d - Apertural view of G. ardens from the Middle to Upper Pleistocene
N2 layer of Kyllini (NW Peloponnesus, Greece), Ht = 10.6 mm, D =
11.4 mm.
variation testifies to the wide diversification of this
genus.
Remarkable morphological affinities between the
new species described and other congeners are lacking,
especially for Gibbula marialuisae n. sp.: while a single
V. Garilli - New Mediterranean Pleistocene taxa of Gibbula
or a few main characters (such as sculpture, protoconch
shape, coloration pattern) pool, other remarkable
characters decidedly diverge. Although a certain degree
of similarity does exist between G. umbilicaris and G.
mariaeangelae n. sp., any attempt to better understand
the systematic-phylogenetic setting of the new species
would be risky on the basis of the resemblances noted
here.
The description of Gibbula mariaeangelae n. sp. and
G. marialuisae n. sp. from Cartiera Mulino and Kyllini,
together with the recently discovered G. olympica, from
the same Greek site (Garilli et al., 2005), contributes to
a more detailed knowledge of the genus Gibbula in the
Mediterranean Pleistocene. Further studies would be
useful for better outlining composition and diversity of
this genus through the Neogene-Quaternary, and for better
understanding the phylogenetic relations between fossil
and extant species.
ACKNOWLEDGMENTS
My special thanks to Stefano Palazzi (Modena, Italy) for
his precious and indefatigable assistance during the field work
“Kyllini 2004”. He also picked paratypes 1 and 2 of Gibbula
mariaeangelae n. sp. and reviewed an early draft of the
manuscript. I also warmly thank Eugenio Di Liberto (Palermo,
Italy), Luca Galletti and Francesco Pollina (APEMA, Palermo),
who assisted me during field working at Kyllini. Luca Galletti,
with passion, also helped me in sampling the Cartiera Mulino
site. Thanks also to Giuseppe Buccheri and Antonino Greco
(Dipartimento di Geologia e Geodesia, University of Palermo)
for supporting the above mentioned field trip, to Maria
Antonietta Rosso (Dipartimento di Scienze della Terra,
University of Catania, Italy), who allowed access to the Cartiera
Mulino collection, and to Evi Vardala-Theodorou (Goulandris
Natural History Museum, Kifissia, Greece), who provided the
catalogue number of G. mariaeangelae n. sp. (holotype). I am
also grateful to Luca Bertolaso (Correggio, Reggio Emilia, Italy)
for providing useful literature. This article greatly benefited from
the comments by the referees Rafael La Perna (Dipartimento di
Geologia e Geofisica, University of Bari, Italy) and Robert
Marquet (Institut Royal des Sciences Naturelles de Belgique,
Département de Paléontologie, Brussels, Belgium). I am
extremely grateful to Alan G. Beu (Institute of Geological and
Nuclear Sciences, Lower Hutt, New Zealand), who added
valuable comments to the revised manuscript and improved my
English.
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Manuscript received 21 October 2008
Revised manuscript accepted 14 March 2009