Introduction

The family Rissoidae includes some of the most diverse gastropod groups, with numerous genera inhabiting a great variety of environments, from shallow to bathyal depth, in the Mediterranean, Atlantic, Indo-Pacific, and the temperate Australian and New Zealand coasts (Ponder 1985). The first record of this family dates back to the late Lower Jurassic of Europe, with a discrete differentiation in Middle Jurassic (Ponder 1985; Conti et al. 1992; Kaim 2004; Schulbert and Nützel 2009). Strong diversification occurred during the Tertiary, particularly in the Euro-Mediterranean area (Sacco 1895; Seguenza 1903; Cossmann 1921; Lozouet 1998; Kowalke and Harzhauser 2004; Landau et al. 2004; Chirli 2006).

As with other small gastropods, most fossil rissoid shells preserve the larval shell (protoconch), which provides information on the larval biology of their respective species (Shuto 1974; Jablonski and Lutz 1983) and, in several cases, provides a helpful taxonomic tool for separating taxa (Ponder 1985). However, because of the high degree of diversification and confusion caused by convergence in shell characters, most of these gastropods are difficult to classify, particularly at the genus and species level. As a consequence, several attempts to separate groups at genus-subgenus level, especially within the very polymorph genus Alvania Risso, 1826 and closely related nominal genera, failed or simply showed the differences to be inconsistent (Ponder 1985; Garilli 2008; Garilli and Parrinello 2010). Conversely, successful results have been achieved in the Late Paleocene—Late Neogene genus Galeodinopsis Sacco, 1895 on the basis of an accurate taxonomic approach involving a detailed morphological study of protoconch and teleoconch characters, with special regard to teleoconch microsculpture (Garilli 2008). Notwithstanding this, the actual number of species within Galeodinospis is not at all defined, mainly due to the lack of a complete taxonomic setting. Actually several taxa, such as Alvania, Alvinia Monterosato, 1884, Arsenia Monterosato, 1891, Flemellia Nordsieck, 1972, and Manzonia Brusina, 1870, have been or could be related to Galeodinopsis but without the support of taxonomical comparative analyses based on in depth studies of teleoconch and protoconch features involving type species. Consequently the origin of Galeodinospsis and its possible phyletic relationships with close genera are still to be defined.

Fig. 1.

Location of the study sites in the Euro-Mediterranean area. Open circles, studied from bibliographic sources; shaded circles, studied from museum/private collections.

The main aim of this study is to provide an exhaustive taxonomic data set of Galeodinopsis allowing a rediscussion of its phyletic link to the other closely related rissoid taxa. We therefore describe in detail protoconch and teleoconch features of Galeodinopsis species from the Tertiary of central Europe and the eastern Atlantic-Mediterranean area (Fig. 1). Comparative studies between Galeodinopsis and type species of related genera are also provided. The palaeoecological and paleogeographical occurrences of Galeodinopsis is discussed. A new species of this genus from the Cenozoic of north-central Europe is also described.

Institutional abbreviations.—BGR, Bundesanstalt für Geowissenschaften und Rohstoffe, Berlin, Germany; IRSNB, Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium; MGUP, Museo Geologico G.G. Gemmellaro, Università di Palermo, Italy; MNHN, Muséum National d'Histoire Naturelle, Paris, France; MNHU, Museum für Naturkunde der Humboldt Universität, Berlin, Germany; MPOB, Museo di Paleobiologia e dell'Orto Botanico, Università di Modena and Reggio Emilia, Modena, Italy; MZB, Museo di Zoologia dell'Università di Bologna, Italy; MZPD, Museo di Zoologia P. Doderlein, Università di Palermo, Italy; SMF, Senckenberg Forschungsinstitut und Naturmuseum, Malakologie, Frankfurt am Main, Germany; UCBL, Université Claude Bernard Lyon 1, Lyon, France.

Other abbreviations.—AR, Agatino Reitano collection (Tremestieri Etneo, Catania, Italy); Coll(s)., collection(s); Ht, total shell height; EM, collection Ecole Nationale Supérieure des Mines de Paris; MF, Maurizio Forli collection (Prato, Italy) ex Stefano Palazzi collection (Milo, Catania, Italy); VG, Vittorio Garilli collection; W, shell width.

Historical background

Sacco (1895) described Galeodinopsis as a subgenus of Alvania, but Ponder (1985) did not follow this separation and considered Galeodinopsis to be a synonym of Alvania. Recently, Galeodinopsis has been re-evaluated as a distinct genus representing shells with characters shared by the genera Alvania and Manzonia Brusina, 1870 (Garilli 2008). In particular, mainly on the basis of the characters of the type species, the Miocene to Recent species Rissoa tiberiana Coppi, 1876 (Fig. 2), Galeodinopsis is characterized by an Alvania-like shape, with an inflated last whorl usually bearing varices and a large aperture resembling that of Galeodina Monterosato, 1884 (= Alvania according to Garilli 2008), and a Manzonia- like combination (see also below) of characters such as the double-rimmed outer lip, the teleoconch pitted microsculpture, and the netted protoconch 1 (Garilli 2008). Apart from the type species, only the Oligocene species “Rissoa Duboisii Nyst, 1845” has been included in Galeodinopsis, whereas the Recent Macaronesian species R. spreta Watson, 1873 was doubtfully considered a close species (Garilli 2008). The fossil species R. multicostata Speyer, 1864, compared with G. tiberiana by the same author, was tentatively placed in Alvinia, but without an in-depth critical review.

The genus Manzonia (Fig. 3), type species Turbo crassus Kanmacher in Adams, 1798, includes species most of which are characterized by ovate-conic-elongate shells bearing robust axial sculpture, formed by strongly curved to sinuous, opisthocline ribs in Manzonia s. s., and strong, smooth spiral cords on the base of the shell. Other relevant characters are the markedly duplicated peristome, the netted sculpture of protoconch 1 (in multispiral protoconchs assumed to indicate planktotrophic larval development; Fig. 3G₂) and a characteristic teleoconch microsculpture, consisted of a pitted surface on flat spiral cords (Ponder 1985; Moolenbeek and Faber 1987a) and roughly prismatic elements forming numerous, very fine spiral threads in the interspaces between primary cords (Garilli 2008; see Fig. 3A₂, B₂, G₄). Manzonia shells do not bear varices (apart from that surrounding the outer lip); to our knowledge the sole specimen with a varix on the last whorl is a Manzonia sp. from the early Late Miocene of Montegibbio (Modena, northern Italy) (Fig. 3H). Subgeneric division within Manzonia is still debated as well its degree of affinity to Alvania. The classification of Alvinia Monterosato, 1884 (type species Alvania weinkauffi Weinkauff, 1868 ex Schwartz von Mohrenstern ms) as a subgenus of Manzonia, as proposed by Ponder (1985) and accepted by Kowalke and Harzauser (2004), was not followed by Moolenbeek and Faber (1987c). Even the consideration of Flemellia Nordsieck, 1972 (new name for Seguenziella, Sacco, 1904, new name for Taramellia Seguenza, 1903, new name for Flemingia Jeffreys, 1884; see Ponder 1985) as a Manzonia-linked taxon appears to be controversial, because its type species, Turbo zetlandicus Montagu, 1815, was only provisionally placed in Manzonia (Flemellia) by Moolenbeek and Faber (1987c), while Ponder (1985) considered it to be a species of Manzonia (Alvinia), as he considered Flemellia to be a synonym of Alvinia. Conversely, Bouchet and Warén (1993) considered Flemellia to be a synonym of Alvania. The type species of Alvinia has a turrited-shouldered shell lacking the typical microsculpture and the marked duplication of the peristome (Figs. 4A, B, 5B) seen in the type species of Manzonia, and its protoconch is paucispiral and characterized by discontinuous spiral cords of rough tubercles. Alvania, type species Turbo cimex Linnaeus, 1758, and Arsenia, type Turbo punctura Montagu, 1803, have a conical-ovate shell without a shoulder, but with a simple outer lip; protoconch 1 in Alvania and Arsenia is characterized by spiral elements and very fine dots, and the microsculpture is weak to obsolete (Figs. 6, 7C–E). Some Alvania species bear stronger microsculpture with discontinuous fine threads representing a sort of Alvinia-impoverished pattern (Garilli 2008; Garilli and Parrinello 2010). The taxonomical state of the art is also complicated by the features of species such as T. zetlandicus and Rissoa testae Aradas and Maggiore, 1844 (type species of Actonia Monterosato, 1884, regarded as synonym of Alvania by Ponder [1985] and Bouchet and Warén [1993]): T. zetlandicus has a shell shape and microsculptural pattern (Figs. 4C₁, C₂, D, 5A) similar to those seen in the type species of Alvinia, and shares the netted pattern of protoconch 1 and the duplicated peristome (Fig. 4C₁, C₃, C₄) with Manzonia s.s.; R. testae (Fig. 8) has shell shape and protoconch characters comparable to those of Manzonia, but has a microsculpture similar to that of Alvinia and Flemellia. All this makes the relationship between Alvania, Alvinia and Manzonia yet to be established, despite Gofas (2010), supporting Ponder's (1985) view, emphasizing that even species lacking the pitted microsculpture may be regarded as closer to Manzonia than to Alvania. Ponder (1985) also suggested that Manzonia (Alvinia) may have diverged from Alvania early in the Tertiary.

Fig. 2.

Rissoid gastropod Galeodinopsis tiberiana (Coppi, 1876), type species of Galeodinopsis Sacco, 1895 from Rio Grizzaga sands, Gagliardella, Fogliano, Maranello, Modena, N Italy, type locality, Piacenzian, Pliocene. A. Specimen ex MF, MZPD Mal 2035a, in apertural view. B. Specimen ex MF, MZPD Mal 2035b, in dorsal view. C. Specimen ex MF, MZPD Mal 2035c showing typical Manzonia-like teleoconch microsculpture (C₁) and detail of protoconch 1 with netted sculpture (C₂). Black arrows indicate the protoconch 1/protoconch 2 boundary. Scale bars: A, B, 1 mm; C, 20 µm.

An exhaustive palaeontological dataset on these arguments, with emphasis on possible transitional steps between most of these taxa, has never been provided. The only well-established Manzonia species from the Paleogene of Europe are Alvania foraminata Lozouet, 1998, from the French Late Oligocene, Chattian, and Rissoa moulinsi d'Orbigny, 1852 known from the Chattian and Miocene of central-western Europe, both showing all the main distinctive characters mentioned above (see Lozouet 1998: fig. 9f–j; Garilli 2008). More species occurred during the European Neogene (Kowalke and Harzhauser 2004; Garilli 2008 and references therein), where diversification involved several indisputable Manzonia taxa such as Rissoa (M.) falunica Morgan, 1915, R. (M.) pontileviensis Morgan, 1915, Cyclostoma scalare Dubois, 1831, Flemingia subzetlandica Boettger, 1907 (possibly = M. zetlandica var. miocrassicosta Sacco, 1895; see Kowalke and Harzhauser 2004: fig. 8A; Fig. 3). Today, one of the most Manzonia species-rich provinces is represented by the northeastern Atlantic seamounts and the Macaronesian archipelago (Moolenbeek and Faber 1987a–c; Gofas 2007), where the high diversification is testified to by species somewhat morphologically distant from the type species, but showing some typical characters. Apart from doubtful Late Cretaceous records (Ponder 1985), the earliest occurrence of Alvania is from the Eocene of Europe (Le Renard 1990; MNHN Fossil Database of Tertiary shells and references therein), where this genus underwent strong diversification during Neogene—Recent time (e.g., Sacco 1895; Bouchet and Warén 1993; Giannuzzi-Savelli et al. 1996; Chirli 2006). As for Alvinia, less is known about the palaeontological record, although it is clear enough that species resembling the type species occurred earliest in the Eocene, Lutetian, of France (Le Renard 1990; MNHN Fossil Database of Tertiary shells, with references), also with shells not at all distant from Alvania. It assumed the characteristic turrited shape in the Miocene of the central Paratethys and of the North Sea Basin (see Bałuk 1975, as Alvania (Taramellia); Kowalke and Harzhauser 2004, with references).

Fig. 3.

Species of rissoid gastropod Manzonia Brusina, 1870. A. Manzonia scalaris (Dubois, 1831); specimen ex MF, MZPD Mal 2039 from Valea Cosului, Lapugy, Banat, Romania, Badenian, Miocene, in apertural view (A₁); microsculpture (A₂). B. Manzonia subzetlandica (Boettger, 1907); specimen ex MF, MZPD Mal 2038 from the same site as in A, in apertural view (B₁); microsculpture (B₂). C. Manzonia moulinsi (d'Orbigny, 1852), specimen ex MF, MZPD Mal 2037 from Albig, Alzey, Worms, W Germany, Rupelian, Oligocene, in apertural view. D. Manzonia pontileviensis (Morgan, 1915), specimen ex MF, MZDP Mal 2041 from Moulin de Charenton, Pontlevoy, Loire Basin, France, Middle Miocene, in apertural view. E. Manzonia falunica (Morgan, 1915), specimen ex MF, MZPD Mal 2040 from Ferriere-Larcon, Loire Basin, Middle Miocene, in apertural view. F, G. Manzonia crassa (Kanmacher in Adams, 1798), type of Manzonia; from N2 layer of Garilli (2011), Kyllini, Elea, NW Peloponnesus, Greece, Late Pleistocene. F. Specimen ex VG, MZPD Mal 2043a in profile view. G. Specimen ex VG, MZPD Mal 2043b, in apertural view (G₁); netted sculpture of protoconch 1 (G₂), white arrow indicates the protoconch 1/protoconch 2 boundary; teleoconch microsculpture (G₄), detail showing the typical pitted pattern formed by very short axial bridges (G₃). H. Manzonia sp., specimen ex MF, MZPD Mal 2042 from Rio delle Bagole, Montegibbio, Modena, N Italy, Tortonian, Late Miocene, in apertural view showing a varix on the last whorl. Scale bars: F, G₁, 1 mm; A₁, B₁, C₁, D, E, H, 500 µm; A₂, B₂, G₂–G₄, 20 µm; C₂, 10 µm.

Fig. 4.

Rissoid gastropod Alvinia weinkauffi (Weinkauff, 1868 ex Schwartz von Mohrenstern ms), type species of Alvinia Monterosato, 1884, matching Weinkauff's illustration (1885: pl. 21: 14, 15), and Alvinia zetlandica (Montagu, 1815), type species of Flemellia Nordsieck, 1972. A, B. Alvinia weinkauffi. A. Specimen ex VG, MZPD Mal 2047, Recent, infralittoral bottom off Capo Gallo, Palermo NW Sicily, in apertural (A₁) and profile (A₂) views. B. Specimen ex VG, MZPD Mal 2048, Recent, infralittoral bottom (37 m deep) off Formica Island, W Sicily, in dorsal view (B₁), protoconch in dorsal view (B₂), and close-up of sculpture (B3). C, D. Alvinia zetlandica, Calabrian, Early Pleistocene, Lazzaro, Vallone Catrica, Reggio Calabria, S Italy. C. Speci men ex MF, MZPD Mal 2046a, in apertural (C₁) and profile (C₂) views, protoconch in dorsal view (C₄) and close-up showing the netted sculpture of protoconch 1 (C₃). D. Specimen ex MF, MZPD Mal 2046b, in dorsal view. White arrows indicate protoconch/teleoconch demarcation. Scale bars: A, B₁, C₁, C₂, D, 1 mm; B₂, 150 µm; B₃, 75 µm; C₃, C₄, 30 µm.

Fig. 5.

Teleoconch microsculpture in the type species of rissoid gastropods Alvinia Monterosato, 1884 and Flemellia Nordsieck, 1972. A. Alvinia zetlandica (Montagu, 1815), type species of Flemellia, ex MF, MZPD Mal 2046a (same specimen as in Fig. 4C), Calabrian, Early Pleistocene of Lazzaro, Vallone Catrica, Reggio Calabria, S Italy, showing closely spaced spiral threads on shell surface at different magnifications. B. Alvinia weinkauffi (Weinkauff, 1868 ex Schwartz von Mohrenstern ms), type species of Alvinia, ex VG, MZPD Mal 2048 (same specimen as in Fig. 4B), Recent, infralittoral bottom (37 m deep) off Formica Island, W Sicily, showing narrow spiral threads on shell surface at different magnifications. Scale bars: A₁, B₁, 50 µm; A₂, B₂, 10 µm.

Material and methods

The examined material is housed in several European institutions. Part of this material was provided by private collectors or collected by the first author, and is now housed in MZPD. Another part, used for comparison, comes from samples collected during the oceanographic field trip CS'96 in the Strait of Sicily (vessel “Urania”, Chief Scientist Marco Taviani) and is now housed in MZB.

In the parts dedicated to each species of Galeodinopsis, a list of the material is provided with all information given on the original labels. An abbreviated list of essential synonymy and/or chresonymy is also provided. For all the discussed species, four to five shells were studied by SEM, using LEO 420 SEM and Philips XL30 ESEM. SEM pictures of the type specimen of Rissoa duboisii from Nyst coll. were provided by IRSNB. Those of material at UCBL were provided by Arlette Armand (U.F.R. Sciences de la Terre, Lyon, France). With the exception of material loaned by public institutions, specimens examined by SEM were cleaned in a Bransonic 5 ultrasonic machine using distilled water. Specimens from public institutions were cleaned using a very fine brush wet with distilled water. Particular attention was given to the protoconch and teleoconch microsculpture as sources of taxonomic characters at species and genus level. The number of protoconch whorls was counted according to Verduin's (1977) method. Shells were measured using a stereomicroscope provided with a cross-line micrometer eyepiece and/or by SEM micrometer tool. The type specimen of Rissoa duboisii was measured on the SEM images. All the shells contained in each studied lot were measured with the exception of Galeodinopsis tiberiana from MF (with more than 200 shells), for which only selected specimens were measured, in particular those assumed to be at terminal growth. Dimensions of the shell at MNHU (catalogue number MB.Ga.43) are from Tembrock (1964: pl. 7: 6). For lots containing numerous shells, measurements are given for selected specimens together with average value and standard deviation. Measurements are shown in Supplementary Online Material at  http://app.pan.pl/SOM/app59-Garilli_Parrinello_SOM.pdf. The position of varix/varices on the last whorl is indicated in degrees of the angle formed by the plane of the varix and the outer lip. Geographical and stratigraphical distributions of each discussed species are based on the examined material and the literature. Published records were critically evaluated on the basis of good illustrations, satisfactory descriptions and cross-checked references. As for material from institutions and private collections, in general we followed the stratigraphical attribution reported by the collectors.

Fig. 6.

Rissoid gastropod Alvania cimex (Linnaeus, 1758), type species of Alvania Risso, 1826, ex VG, MZPD Mal 2045, from N2 layer of Garilli (2011), Kyllini, Elea, NW Peloponnesus, Greece, Late Pleistocene. A. Specimen ex VG, MZPD Mal 2045a; shell in apertural view (A₁), protoconch in dorsal view (A₃), and a close-up of teleoconch surface (A₂) illustrating the very obsolete spiral elements and the incremental scars. B. Specimen ex VG, MZPD 2045b, shell (B₁) and protoconch (B₂) in profile view, and fine spiral threads on protoconch 1 (B₃). Scale bars: A₁, B₁, 1 mm; A₂, A₃, B₂, 100 µm; B₃, 30 µm.

Stratigraphical notes on some recovery areas

Agatino Reitano provided part of the analysed shells as coming from unspecified sandy layers cropping out between the ORTO 1 and KYLA3a samples of Dell'Angelo et al. (2012) in the Altavilla succession (Altavilla Milicia, NW Sicily, Italy). The age of these samples, presumably Late Zanclean— early Late Piacenzian, is from Dell'Angelo et al. (2012).

The “Middle Pliocene” age indicated by the respective collectors for some sites, following the three-fold Zanclean— Piacenzian—Gelasian division, is intended to be Piacenzian, according to the recently ratified, two-fold Pliocene stratigraphy (Gibbard et al. 2010).

Most of the species discussed here are from the Late Paleogene of Europe (mostly Germany and France), where the stratigraphy of the Eocene/Oligocene boundary has been debated (see Snyder et al. 1985 for a synthetic overview). As a consequence, the attribution of the Latdorfian Stage (partially corresponding to the Late Eocene/Early Oligocene Tongrian) (Müller 2011 with references) to the Eocene or to the Oligocene Series is still controversial. In the first case, involving a two-fold Oligocene (Rupelian—Chattian), the Latdorfian, as well as at least part of the Tongrian, should be included in the Late Eocene (Priabonian). In the second case, the Lat- dorfian would be the lower part of a three-fold Oligocene, as presumably intended by several 19th century and later authors (e.g., Speyer 1864; Koenen 1867; Wiechmann 1871; Görges 1957; Anderson 1960), who discussed some of the species here studied. This matter is made harder by the gap in many Late Paleogene successions due to the marked regression recorded at the Eocene/Oligocene boundary (Cavalier et al. 1981). The International Commission on Stratigraphy (see the International Stratigraphic Chart, available at  http://www.stratigraphy.org/index.php/ics-chart-timescale) has ratified a two-fold Oligocene (Rupelian—Chattian) subdivision. This stratigraphical issue is beyond the scope of the present article, for which we have considered material indicated as from Latdorf (or Latdorfian/Lattorfian) as older than that reported from Rupelian or Chattian. Material referred to middle Oligocene, following the three-fold division, therefore is Rupelian in age.

Fig. 7.

Rissoid gastropods Alvania areolifera (Sandberger, 1863) (A, B) and Alvania punctura (Montagu, 1803), type species of Arsenia Monterosato, 1891 (C–E). A. Specimen MNHU MB.Ga.7749.1, Waldböckelheim, Rheinland-Pfalz, W Germany, Rupelian, Oligocene, in apertural view. B. Specimen MNHU MB.Ga.7749.2, same site as in A, in dorsal view. C. Slender specimen ex VG, MZB 49971, Recent, station CS'96/54, 135 m deep, Graham Bank, Strait of Sicily, in dorsal view (C₁), protoconch (C₂), sculpture of protoconch 1 (C₃), detail of teleoconch microsculpture (C₄). D. Specimen ex VG, MZPD Mal 2044a, Sicilian, Early Pleistocene, Acqua dei Corsari, Ficarazzi, Palermo, NW Sicily, in apertural view. E. Specimen ex VG, MZPD Mal 2044b, with inflated last whorl, same site as in D, in dorsal view. Scale bars: A, B, C₁, D, 1 mm; E, 500 µm; C₂, 100 µm; C₃, C₄, 25 µm.

Fig. 8.

Rissoid gastropod Alvinia? testae (Aradas and Maggiore, 1844), type species of Actonia Monterosato, 1884, ex VG, MZB 49972, Recent, station CS'96/71, 118.9 m deep, Graham Bank, Strait of Sicily. A. Specimen ex VG, MZB 49972a, in profile view (A₁), note the profile of the outer lip comparable to that of Manzonia Brusina, 1870 and Flemellia Nordsieck, 1972; teleoconch microsculptural pattern (A₂, A₃) comparable to that of Alvinia and Flemellia. B. Specimen ex VG, MZB 49972b, in apertural view (B₁), showing the double-rimmed aperture comparable to that of Manzonia and Flemellia; protoconch in profile view (B₂), the netted sculpture of protoconch 1 (B₃), and a panoramic view of microsculpture (B₄). Scale bars: A₁, B₁, 1 mm; B₂, 100 µm; B₃, B₄, 30 µm; A₂, A₃, 10 µm.

An (Early) Chattian age is indicated for the deposit at Söllingen (Janssen, 1978a, 1979 and personal communication, 2014).

As for most of the material from the Paris Basin, the collecting sites (Jeure and other localities cited by Deshayes 1864) are from the “Sables supérieurs”, therefore from the Late Tongrian, actually (Early) Rupelian (Harris and Burrows 1891; Keen 1972). The material collected at (Château) Brunehaut (locality not cited by Deshayes 1864) is from the same age/formation (Harris and Burrows 1891). The Late Tongrian material from Klein-Spauwen “Tongrien ass. sup. Tg2b” (type locality of Rissoa duboisii Nyst, 1845) is also of Early Rupelian age (see also Anderson 1960: 25).

Systematic palaeontology

Fig. 9.

Rissoid gastropod Galeodinopsis biangulata (Deshayes, 1864) from Glimmerode, Hessisch-Lichtenau, SE of Kassel, Hessen, Late Oligocene, Chattian (A–E), Waldböckelheim, Rheinland-Pfalz, Rupelian sands (F). A. Specimen ex MF, MZPD Mal 2036a, in apertural view (A1); detail of a subsutural cord (A₂). B. Specimen ex MF, MZPD Mal 2036b, in profile view (B₁), teleoconch microscultpure (B₂). C. Specimen ex MF, MZPD Mal 2036c, in dorsal view (C₁); detail of protoconch showing traces of the netted sculpture on protoconch 1 (C₂); protoconch in dorsal view (C₃), black arrows indicate the protoconch/teleoconch boundary. D. Slender specimen ex MF, MZPD Mal 2036d in apertural view. E. Specimen ex MF, MZPD Mal 2036e with strong sculpture, in apertural view. F. Slender specimen MNHU MB.Ga.7744 with weaker sculpture resembling Manzonia areolifera sensu Cossmann (1921), in apertural (F₁) and dorsal (F₂) views. Scale bars: D–F, 1 mm; A₁, B₁, C₁, 500 µm; C₃ 200 µm; C₂, 50 µm; A₂, B₂, 20 µm.

Fig. 10.

Rissoid gastropod Galeodinopsis biangulata (Deshayes, 1864) from the Oligocene of the Paris Basin. A. Possible syntype specimen UCBL EM 31000, Deshayes collection, in profile view, resembling Deshayes' illustration (1866: pl. 24: 30). B. Original label of the same specimen. C. Specimen UCBL, EM 30996, Paris Basin collection from Jeures, in apertural view. D. Specimen UCBL, EM 30997, Deshayes collection, in profile view (D₁); protoconch in profile view (D₂), white arrows indicate the protoconch/teleoconch boundary; detail of protoconch showing trace of the netted sculpture on protoconch 1 (D₃), white arrow indicates the protoconch 1/protoconch 2 boundary. E. Specimen UCBL, EM 30998, Deshayes collection, in apertural view, matching Deshayes' illustration (1866: pl. 24: 29) and resembling Manzonia areolifera sensu Cossmann (1921). F. Specimen UCBL, EM 30999, Deshayes collection, in apertural view. Scale bars: A, C, D₁, E, F, 1 mm; D₂, 100 µm; D₃, 30 µm.

Fig. 11.

Rissoid gastropod Galeodinopsis germanica sp. nov., abandoned mine-pit Höllkopf, Glimmerode, south of Hessisch-Lichtenau, Hessen, Germany, Chattian (Late Oligocene) Kasseler Meeressand. A. Holotype SMF 335576, in apertural (A₁), dorsal (A₂), and profile (A₃) views. B. Paratype SMF 336790, in apertural view. C. Paratype SMF 336789, in apertural (C₁) and dorsal (C₂) views; protoconch in dorsal view (C₃), white arrows indicate approximate position of the protoconch/teleoconch boundary; details of protoconch showing sculpture on late protoconch 2 (C₄), protoconch 1 and early protoconch 2 (C₅). D. Paratype SMF 336788, in apertural view (D₁), teleoconch sculpture (D₂), details of microsculpture showing the typical Manzonia-like pitted pattern (D₃, D₄), and the Alvinia-like pattern (white arrows) on the obsolete subsutural cord (D₅). E. Paratype SMF 336787, in apertural view. Scale bars: A₁–A₃, D₁, E, 1 mm; B, C, 300 µm; C₃, D₂, 100 µm; C₄, C₅, 30 µm; D₃, D₅, 20 µm; D₄, 10 µm.

Fig. 12.

A–I. Rissoid gastropod Galeodinopsis semperi (Wiechmann, 1871), the type specimen IRSNB 3956 (Nyst coll.) of synonymous Rissoa duboisii Nyst, 1845, Tg2b layer of Klein-Spauwen, Belgium, Late Tongrian. Specimen in apertural (A), profile (B), and dorsal (C) views; early teleoconch whorls (D); protoconch in profile view (E), black arrows indicate the protoconch/teleoconch boundary; subapertural view (F); detail of protoconch 1 showing trace of the netted sculpture (G); detail of teleoconch sculpture (H); microsculpture on spiral cord (I). J. Original label in Nyst's handwriting with the citation of “type” and references to the original description and illustration in Nyst, 1845. Scale bars: A–C, 1 mm; D 200 µm; E, F, H, 100 µm; G, 50 µm; I, 30 µm.

Fig. 13.

Rissoid gastropod Galeodinopsis semperi (Wiechmann, 1871) from the Paleogene of Germany. A. Juvenile specimen BGR X1239, same specimen as illustrated by Tembrock (1964: pl. 7: 7) as Alvania (Arsenia?) multicostata (Speyer, 1864) var.?, from drill hole Drehna 5/1960, Lusatia/Brandenburg, Oligocene, Chattian, in apertural view (A₁); protoconch in profile view (A₂), white arrows indicate the protoconch/teleoconch boundary; detail of protoconch 1 showing trace of the netted sculpture (A₃); detail of teleoconch sculpture (A₄); teleoconch microsculpture showing the almost flat subsutural cord (A₅). B. Specimen MNHU MB.Ga.7745.1 with delicate sculpture from Magdeburg?, Sachsen-Anhalt, Oligocene, Rupelian, in apertural (B₁), dorsal (B₂), and profile (B₃) views; teleoconch microsculpture on spiral cord (B₄). C. Specimen MNHU MB.Ga.43, from Latdorf, Latdorfian, same specimen classified by Tembrock (1964: pl. 7: 6) as Alvania (Arsenia?) multicostata (Speyer, 1864) var.?, in apertural (C₁) and dorsal (C₂) views. D. Specimen MNHU MB.Ga.7745.2 from Magdeburg?, Sachsen-Anhalt, Oligocene, Rupelian, in apertural view, strongly resembling Rissoa multicostata Speyer, 1864 from the original illustration (pl. 41: 3). Scale bars: B₁–B₃, C, D, 1 mm; A₁, 200 µm; A₂, 100 µm; A₃–A₅, B₄, 20 µm.

Fig. 14.

Rissoid gastropods Galeodinopsis tiberiana (Coppi, 1876) (A–C, F, G) and G. cf. tiberiana (D, E), from the Neogene of the Mediterranean area. Altavilla Milicia, Palermo, NW Sicily, Late Zanclean—early Late Piacenzian, Pliocene (A, D, E); Stirone River, San Nicomede, Parma, N Italy, Pliocene (B); Rio Grizzaga sands, Gagliardella, Fogliano, Maranello, Modena, N Italy, Piacenzian, Pliocene (C, F, G). A. Specimen ex AR, MZPD Mal 2032, in apertural view, showing the typical G. tiberiana-morph. B. Specimen ex MF, MZPD Mal 2034 in profile view, showing the sinuous outer lip curved backwards in the lower part. C. Specimen ex MF, MZPD Mal 2035d, in apertural view, showing more axial and spiral elements. D. Specimen ex AR, MZPD Mal 2033a, in apertural (D₁), profile (D₂), and dorsal (D₃) views, somewhat transitional between specimen as in C and galeodiniform specimens as in E and in Fig. 15; protoconch in profile view (D₄). E. Galeodiniform specimen ex AR, MZPD Mal 2033b, in apertural (E₁) and profile (E₂) views, tentatively assigned to G. tiberiana. F. Specimen ex MF, MZPD Mal 2035e, showing detail of teleoconch sculpture with marked axial ribs. G. Specimen ex MF, MZPD Mal 2035f, showing protoconch in profile view. Black and white arrows indicate the protoconch 1/protoconch 2 and protoconch/teleoconch boundaries, respectively. Scale bars: A–C, D₁–D₃, E, 1 mm; D₄, F, G, 100 µm.

Fig. 15.

Rissoid gastropod Galeodinopsis cf. tiberiana (Coppi, 1876), from the Late Zanclean—early Late Piacenzian, Pliocene of Altavilla Milicia, Palermo, NW Sicily. A. Specimen ex AR, MZPD Mal 2033c with varix, in apertural (A₁), dorsal (A₂), and profile (A₃) views, protoconch (A₆), detail of protoconch 1 with trace of the netted sculpture (A₄), the Manzonia-like teleoconch pitted microsculpture on spiral cord (A₅). B. Specimen ex AR, MZPD Mal 2033d without varix in apertural (B₁), dorsal (B₂), and profile (B₃) views, details of teleoconch sculpture (B₄, B₅) and microsculpture (B₆), protoconch in profile view (B₇). Note the variability of the outer lip: weakly sinuous and curved backward in the lower part (A₃) to almost straight and opisthocline (B₃). Black and white arrows indicate the protoconch 1/protoconch 2 and protoconch/teleoconch boundaries, respectively. Scale bars: A₁–A₃, B₁–B₃, 1 mm; A₆, B₄, B₅, B₇, 100 µm; A₄, A₅, B₆, 20 µm.

Discussion

Taxonomy and evolutionary notes.—The European Tertiary Galeodinopsis species are characterized by a conical- ovate/conical-turrited, Alvania/Alvinia-like shell shape, with a discretely to strongly inflated last whorl and a duplicated peristome outlining a wide aperture. The common occurrence of varices on the last whorl is another important character distinguishing Galeodinopsis. Whereas varices occur in galeodiniform species attributed to Alvania (as a possible case of non-phyletic convergence, see Garilli 2008), they never occur within Alvinia and they very rarely occur in Manzonia. To our knowledge, the only known case of a varicose Manzonia specimen, illustrated in the present paper (Fig. 3H), might be interpreted as a teratological case. The combination of a Manzonia-like netted protoconch 1 and pitted microsculpture possibly represents a further diagnostic character distinguishing Galeodinopsis. However, the characteristic microsculpture is manifested only from the Chattian (Late Oligocene), in Galeodinopsis germanica sp. nov., whereas the older Galeodinopsis species, G. biangulata and G. semperi (Late Eocene—Early Oligocene), have a sort of “protopitted” microsculpture that possibly represents an ancestral character. This microsculpture is due to the near absence (in G. semperi) or strong reduction (in G. biangulata) of the numerous microscopic axial ribs, forming very short bridges between the ridges of the primary spiral cords in the typical pitted pattern. This pattern is comparable to that shown by the living type species of Alvinia (A. weinkauffi), and it particularly resembles that shown by Rissoa testae (type species of Actonia) and Turbo zetlandicus (type of Flemellia). These last two species possibly are related to Alvinia, particularly the former species, which shows the typical turrited shell shape as in A. weinkauffi. It is noteworthy that both Rissoa testae and Turbo zetlandicus show characters (the netted pattern of protoconch 1, the profile of the outer lip and the duplicated peristome) comparable to those of Manzonia species, stressing a certain affinity to this genus. A sort of “protopitted” microsculpture can be seen also in Alvinia planicincta Le Renard, 1990 (see MNHN Fossil Database of Tertiary shells), which lived in the Paris Basin during the late Early Eocene (Early Lutetian), long before the first appearance of Galeodinopsis. Other Alvinia characters, such as the conical-turrited shells usually provided with a subsutural ramp, indicate that the relationship between this group and the oldest Galeodinopsis species is close. In particular, it is worth emphasizing that some of the oldest species attributed to Alvinia from the Eocene of the Paris Basin (see Le Renard 1990) resemble the typical inflated shape of Galeodinopsis. This taxonomical setting demonstrates that Alvinia is morphologically closer to Galeodinopsis than to Manzonia. However, the relationship between this last genus and Alvinia is still remarkable.

The oldest representatives of Manzonia, M. foraminata and M. moulinsi, date from the Oligocene of central western Europe, but its radiation occurred in the European Neogene, when different species lived in the Atlantic province, the Mediterranean area and the Paratethys. From the Oligocene onwards the European Manzonia species differentiated according to evolutionary trends generally involving the strengthening of axial sculpture (in most of the here considered species), a proportional decrease in peristome size and of the width/height ratio (particularly remarkable in the type species), and the remarkable strengthening of the basal cords (evident in the morphological lineage M. foraminata— M. moulinsi) (Fig. 16). Conversely, the greatest diversification within Galeodinopsis occurred in the Late Paleogene of France and Germany, with evolutionary trends involving strengthening of axial sculpture and proportional decrease in the peristome size (G. semperi—G. germanica sp. nov. lineage), on one side, and, on another side (G. semperi—G. biangulata lineage), reinflation of the last whorl (Fig. 16). As for G. tiberiana, this species shows shell characters shared by G. biangulata and G. semperi (mainly the very inflated last whorl) and by G. germanica sp. nov. (mainly the curved axials prevailing over spirals). It is therefore difficult to indicate the origin of G. tiberiana, even hypothetically. However, its pitted teleoconch microsculpture might suggest a possible lineage with G. germanica sp. nov. Particularly, G. germanica sp. nov. has (more than any other congeners) characters so close to those of the Chattian species Manzonia foraminata that the lineage G. germanica sp. nov.—M. foraminata might be interpreted as a transitional step from Galeodinopsis to Manzonia. However, the hypothesis that Manzonia derives from Galeodinopsis through this lineage should be based on a more exhaustive data set. Actually, on the basis of the material studied here, the origin of Manzonia is to be backdated to the Early Oligocene, as Manzonia moulinsi has been recorded from the Rupelian of Germany and therefore preceded the first appearances of G. germanica sp. nov. and M. foraminata (very recently described from the Chattian of the North Sea and Aquitaine Basins, respectively). However, due to the problems of classifying these fossil rissoids and the obsolete approach dedicated to this group, often badly illustrated, especially by old authors (see also Lozouet 1998, for a discussion), it seems to be implausible that these last two species may have been recorded from the Early Oligocene sites under different names.

Fig. 16.

Schematic trend of morphological variation/diversification and supposed lineages within Tertiary species of Galeodinopsis Sacco, 1895 and some Tertiary—Quaternary representatives of Manzonia Brusina, 1870, and synthetic view of the main features of species/group of species. Gray circles indicate stable taxonomic characters; black circles indicate novel characters. The image of Manzonia foraminata is modified from Lozouet (1998).

The shells of Galeodinopsis tiberiana (AR coll.) from the Pliocene of Altavilla (Sicily) are from a mixture of samplings collected at different layers of the Altavilla Milicia succession. These shells showed such wide variation that a somewhat doubtful determination as G. cf. tiberiana was preferred for the smaller ones bearing more numerous axial ribs, which are obsolete to lacking on the last whorl. This characteristic morph, never observed from other localities, appears so distant from the typical ones that it might be interpreted as the result of incipient speciation (chronospeciation?). Detailed, microlayer-by-microlayer sampling of the Altavilla succession, allowing understanding of chronological variations through transitional morphs, possibly would help to verify this assumption.

A few living species from the Macaronesian area, Rissoa moniziana Watson, 1873 and R. spreta Watson, 1873, show some similarities to Galeodinopsis, in particular in their quite inflated last whorl, the weak basal cords and the Manzonia- like microsculpture (Moolenbeek and Faber 1987c: figs. 58–60). The former species has been regarded as belonging to Manzonia (Moniziella) (Moolenbeek and Faber 1987c); the latter has been considered a species of Manzonia (Flemellia) (Moolenbeek and Faber 1987c). The identity of Moniziella is uncertain (see Moolenbeek and Faber 1987c). However, Ponder (1985) put it in synonymy with Alvinia. We have shown that Alvinia and Flemellia lack the pitted surface; therefore the placement of R. moniziana in this group should be questioned.

Palaeobiogeography and palaeoecology.—The oldest occurrences of Galeodinopsis are from the Late Eocene/very Early Oligocene in the North Sea Basin, as testified by the records of G. biangulata and G. semperi in the Latdorfian beds of Germany and of G. semperi in the Late Tongrian of Belgium. The German part of this area, including the satellite basins (e.g., those in the Rhine Graben), was the main hosting area for Galeodinopsis species, as three of its four species lived there; G. biangulata also lived in the Early Oligocene Paris Basin (Fig. 17). The Late Eocene—Oligocene palaeogeographic reconstructions of those areas (Vincent 1990; Rögl 1999: figs. 2, 3; Rasser et al. 2008, with references) outline the North Sea and Paris Basins (N Atlantic realm) as distinct marine provinces separated by the Thule bridge, a wide land-passageway putting Great Britain in communication with central-western continental Europe until the Late Oligocene. At this time sporadic communications between the Atlantic and North Sea Basin occurred in the Channel area, as indicated by Janssen (1978b) on the basis of some Late Oligocene marine faunal affinities between the North Sea Basin and the Aquitaine Basin. However, it is possible that a southernmost connection favoured these interchanges as supposed by Rasser et al. (2008). The distribution of G. biangulata (Fig. 17) indicates that a faunal interchange (possibly unidirectional) between the North Sea and Paris Basins started in the Early Oligocene, when the Thule land-bridge was already in-filled (at least intermittently) in the Channel area, much earlier than had been supposed. The linkage between G. germanica sp. nov. and Manzonia foraminata (from the North Sea and Aquitaine Basins, respectively) suggested here, as well as the Oligocene distribution of M. moulinsi (Aquitaine and North Sea Basins), support the existence of an alternative, southern route towards the Atlantic domain of the Aquitaine Basin, likely through the Upper Rhine Graben (Fig. 17). More palaeobiogeographical data could be useful for understanding whether this interchange was unidirectional, from the North Sea Basin southwards, as suggested by the oldest occurrence of M. moulinsi in the Early Oligocene of Germany.

Fig. 17.

Distribution of European species of Galeodinopsis Sacco, 1895, based on material studied and that from the literature. Dark and light grey vertical segments roughly indicate the Late Paleogene Paris Basin and the southern part of the North Sea Basins, respectively; white segments represent the Mainzer Basin—Upper Rhine Graben (from Rögl 1999 and Rasser et al. 2008, modified). The horizontal black and dark grey segments approximate the Iberian Late Neogene and Aquitaine Late Oligocene—Early Miocene Atlantic domains, respectively; orange dots indicate the southernmost part of the Thule land-bridge joining England with continental Europe (from Vincent 1990, adapted and modified); green line indicates a hypothetical reconstruction of the Late Paleogene shoreline in the North Sea and Paris Basins, allowing communication (smaller red arrow) between the two areas from the Early Oligocene. The red line indicates part of the Central European shoreline (according to Rögl 1999) during very Early Neogene time, showing northwards shifting of the southern coasts of the North Sea Basin. The larger red arrow indicates the hypothesized connection to the Aquitaine Basin. 1, Upper Eocene/very early Oligocene, Latdorf (Koenen 1867; Tembrock, 1964) and Magderburg (Müller 2011); 2, Oligocene, Rupelian, Söllingen (Speyer 1864; Koenen 1867); 3, Oligocene, Chattian, Sternberg (Wiechmann 1871; Anderson 1960); 4, Oligocene, Rupelian, Amsdorf (Gründel 1997); 5, Oligocene, Chattian, Freden (Anderson 1960); 6, Oligocene, Chattian, Ahnetal (Anderson 1960); 7, Oligocene, Chattian, Glimmerode; 8, Middle Oligocene, Magonza basin at Waldböckelheim (Sandberger 1863; Anderson 1960); 9, Oligocene, Chattian, Doberg (Wiechmann 1871); 10, Oligocene, Chattian, Krefeld (Wiechmann 1871), Rumeln (Anderson 1960 ), and Moers (Janssen 1978a); 11, Oligocene, early Rupelian, Klein-Spauwen (Nyst 1845); 12, Oligocene, Rupelian, Paris Basin (Deshayes 1864); 13, Middle Pliocene, Mondego (Landau et al. 2004); 14, Pliocene, Estepona (Landau et al. 2004); 15, Pliocene, Sidi Moussa (Cossmann 1921); 16, Pliocene, Altavilla and Trappeto (Garilli 2008); 17, Lower Pliocene, Magliano Sabina (Garilli 2008); 18, Lower Pliocene, Siena (Chirli 2006); 19, Mio-Pliocene, Modena, Parma, and Piacenza (Coppi 1876; Garilli 2008); 20, Lower to Upper Pliocene, Savona and Asti (Garilli, 2008).

From a palaeocological point of view, it is remarkable that all Galeodinopsis species studied have a multispiral protoconch, indicative of planktonic larval development and, in general, of a high dispersal capability, higher than in species with direct larval development. Notwithstanding this, Galeodinopsis seems never to have lived in the eastern part of the southern margin of the North Sea Basin, nor in the Paratethyan area, even though communication between the North Sea and Mediterranean/Paratethyan areas was established during that time, especially in the Early Oligocene, when ocean circulation supplied water from the North Sea to the Paratethys (Rögl 1999: figs. 1, 2). The distributional gap in the North Sea Basin may be at least partially explained by the paralic condition that affected the southeastern part of the North Sea Basin during Late Oligocene time (Rasser et al. 2008).

Galeodinopsis tiberiana is the only Neogene Galeodinopsis, from the Mio-Pliocene (palaeo)Mediterranean and the Pliocene of Atlantic Portugal, namely areas with a tropical- subtropical climate (Monegatti and Raffi 2001). Today this species is the sole well-established living species of Galeodinopsis, having been recorded from an area (West African coasts, from Mauritania to Angola) that is constrained by an analogous climatic setting. This suggests that the extinct Galeodinopsis species also required warm climatic conditions. Tropical to warm-temperate conditions have been inferred for the Palaeogene of Europe (Vincent 1990) and, more specifically, subtropical conditions were indicated for the Late Oligocene of the North Sea Basin (Rasser et al. 2008). Actually, a warm (possibly tropical-subtropical) climatic regime in the Paleogene of the North Sea Basin is suggested by the analogies (at least at genus level) between the highly diverse molluscan assemblages from the Mediterranean Neogene and the Late Eocene—Oligocene of Germany, southwards to the Mainz basin: several molluscan taxa characteristic for warm climate, such as Bathytoma Harris and Burrows, 1891, Isognomon Lightfoot, 1786, Ficus Röding, 1798, Gemmula Weinkauff, 1875 and others, have been recorded in those areas (Janssen 1978b, 1979; Gründel 1997; Monegatti and Raffi 2001; Müller 2011). Furthermore, warm, tropical to subtropical, marine climatic conditions were inferred for this part of central Europe with particular regard to the Latdorfian faunal complex and similar assemblages of younger (Oligocene) age (Müller 2011). It is remarkable that from the middle Eocene onwards, the Cenozoic continental history of central Europe, in accordance with global marine oxygen isotope records, was characterized by the increasing degree of seasonality, and a short-term cooling at the base of the Aquitanian, approximating the Oligocene/Miocene boundary, was recorded in the Weisselster Basin, in central Germany (Mosbrugger et al. 2005). Also from a palaeogeographical point of view, the area of central-western Europe underwent remarkable changes. During the Early Miocene, marine regressive conditions rewrote the palaeogeography of the North Sea Basin, triggering the progressive reduction of its southernmost part, which was constrained to higher (presumably relatively colder) latitudes. Regressive conditions also caused the disappearance of satellite basins such as those in the Rhine Graben (e.g., the Mainz Basin; Rögl 1999). This palaeogeographic-climatic evolution was possibly responsible for the disappearance of Galeodinopsis from the mid-high latitudes of Central Europe and for its migration to the Iberian Atlantic coasts and into the (paleo)Mediterranean during Mio-Pliocene time. At the end of the Pliocene, at around 2.6 My B.P. (approximating the Piacenzian/Gelasian boundary), the marked onset of the continental ice sheet in the Northern Hemisphere (Shackleton et al. 1984) triggered stepwise climatic deteriorations at lower latitudes, causing the Mediterranean extinction of several molluscan taxa (Monegatti and Raffi 2001). The new climatic regime probably was the main cause of the disappearance of Galeodinopsis from the Mediterranean and its further migration towards the subtropical-tropical West Africa coasts, where this genus still lives.

As for the ecological/bathymetrical requirements of Galeodinopsis, it is remarkable that for the Late Paleogene around Magderburg and Glimmerode (southern part of the North Sea Basin), where G. biangulata and G. semperi lived, the palaeofauna indicates normal marine conditions in rocky-sandy shore environments (Janssen 1978b; Mueller 2008, 2011). Also, the requirements of G. tiberiana are comparable, as indicated by its occurrence in the Pliocene sands of the Mediterranean Altavilla site, the depositional setting of which was mainly referred to infra-circalittoral shelf conditions (Dell'Angelo et al. 2012).

Conclusions

At least four European rissoid species are identified as belonging to Galeodinopsis: G. biangulata, G. germanica sp. nov., G. semperi, and G. tiberiana. A possible incipient speciation from G. tiberiana to the morph here tentatively determined as G. cf. tiberiana should be verified by in-depth studies based on more material well dated stratigraphically.

Species of Galeodinopsis are warm, marine, shallow-water taxa, from rocky or sandy bottoms. The genus originated during the Late Eocene—Early Oligocene in the southern part of the North Sea Basin. A combination of palaeogeographical and climatic events probably played an important role in determining the disappearance of Galeodinopsis from central Europe at the end of the Oligocene, and its Neogene shifting to lower Euro-Mediterranean latitudes. Climatic deterioration events are possibly the main cause of the disappearance of this genus from the Mediterranean and the eastern Atlantic midhigh latitudes during the Pliocene and its later migration to the Recent tropical coasts of West Africa. The palaeobiogeography deduced for Galeodinopsis indicates that connections between the North Sea and Paris Basins through the Channel area commenced during the Early Oligocene. Also, a connection between the Aquitaine Basin and the southernmost part of the North Sea Basin likely formed during the Late Oligocene, possibly through the Upper Rhine Graben, as testified by the occurrence in those areas of Manzonia moulinsi.

In the light of the in-depth taxonomic data set provided here, the combination of characters such as the teleoconch microsculpture and the netted pattern of protoconch 1 represents a very diagnostic key within Galeodinopsis and Manzonia, which should be regarded as a monophyletic group much closer to Alvinia than to Alvania. As for Alvinia, species such as Turbo zetlandicus (type of Flemellia) could be regarded as belonging therein; even Rissoa testae, type of Actonia, might be included therein, although more exhaustive argumentations are needed. In particular, the chronological/ transitional lineage Alvinia—Galeodinopsis—Manzonia is supported by shell and protoconch 1 characters and, above all, by the analyzed microsculpture: raised and variably closely spaced ridges in Alvinia; wider and closely spaced ridges in the ancestral species of Galeodinopsis, flat and almost fused ridges in other Galeodinopsis and Manzonia species. Effectively, on one side, the oldest Galeodinopsis species appear to have evolved from some early Late Eocene species that could be regarded as Alvinia; the strong relationship between Alvinia and Galeodinopsis is supported by several characters shared by G. biangulata and, especially, G. semperi, and the type species of Alvinia and Flemellia. On the other side, the similarities between Galeodinopsis and Manzonia are so obvious, particularly for the hypothesized lineage G. germanica sp. nov.—Manzonia foraminata, that the latter genus appears to have evolved during the Oligocene from the former rather than from Alvania/Alvinia. Therefore, Galeodinopsis can be seen as a taxon intermediate between Alvinia and Manzonia.

The only well-established living species of Galeodinopsis, G. tiberiana, could be seen as a very interesting tool for investigating the supposed lineage Alvinia—Galeodinopsis—Manzonia. In particular, more independent characters, such as those based on genetic and anatomical comparisons between Manzonia species (such as the Euro-Mediterranean type species M. crassa), Alvinia species (such as the NE Atlantic-Mediterranean species A. weinkauffi and A. zetlandica) and the West African species G. tiberiana could be extremely interesting for this purpose. Similar studies on the Macaronesian Rissoa moniziana and R. spreta, which show intermediate character between Manzonia and Galeodinopsis, would be useful as well to shed light on a number of living species of Galeodinopsis.