the late cretaceous genera cuvillierinella ... - GeoScienceWorld

Journal of Foraminiferal Research, v. 41, no. 2, p. 167–181, April 2011

THE LATE CRETACEOUS GENERA CUVILLIERINELLA, CYCLOPSEUDEDOMIA, AND RHAPYDIONINA (RHAPYDIONINIDAE, FORAMINIFERIDA) IN SHALLOW-WATER CARBONATES OF PYLOS (PELOPONNESE, GREECE) VICENT VICEDO1,4, GIANLUCA FRIJIA2, MARIANO PARENTE3 ABSTRACT

AND

ESMERALDA CAUS1

are frequent among the large B-forms, which may reach diameters .1.5 cm. Rhapydioninid chambers have multiple apertures and are structurally subdivided into tubular chamberlets by an endoskeleton consisting of septula and floors. Septula separate external cortical chamberlets (‘‘logettes primaires’’ in Fleury, 1974; ‘‘logettes sube´pidermiques’’ in Reichel, 1984), while the floors divide the inner part of the chamber lumen into superposed levels of medullar chamberlets (‘‘logettes secondaires’’ in Fleury, 1974; Reichel, 1984). In certain genera (e.g., Pseudochubbina de Castro, 1990), the medullar chamberlets are distributed in a solid basal mass appearing as radial tubular passages. The chamberlets of the same chamber communicate through a preseptal space, whereas the chamberlets of consecutive chambers are connected by interlocular foramina. The endoskeletal elements and foramina show either parallel or crosswise-oblique disposition with respect to the radial axes of the cortical chamberlets. Residual pillars, rooted on the floors, support a trematophore in the central area of the apertural face. Some architectural characters of the shell, like the chamber arrangement or the final shape of the adult specimens, may be common to several genera within the Rhapydioninidae; thus their use of such characters as diagnostic at the genus level may lead to erroneous identifications. Several examples in the literature strengthen this opinion. The A and B forms of Rhapydionina Stache, 1913, as presently accepted, were originally described as two different genera, Rhapydionina and Rhipidionina, respectively (see discussion in Hottinger, 2007). The former included conical specimens, whereas the latter included fanshaped ones. Conversely, two separate genera, the Late Cretaceous Tethyan Cuvillierinella Papetti and Tedeschi, 1965, and the Early Tertiary age Caribbean genus Raadshoovenia van den Bold, 1946, were considered synonyms by various authors (further information in Fleury and Fourcade, 1990; Vicedo, 2008; Vicedo and others, 2009). The present article focuses on three genera: Cuvillierinella Papetti and Tedeschi, 1965, Cyclopseudedomia Fleury, 1974, and Rhapydionina Stache, 1913 that co-exist in the sediments belonging to the Late Cretaceous Global Community Maturation cycle (Hottinger, 2001), and whose microspheric shells during ontogeny tend to develop similar chamber arrangements and comparable shapes (Figs. 5.4, 9.8, 11.9). Detailed stereographs of the shell structures of each genus are presented to illustrate the similarities and differences that facilitate thin-section identifications. Two new species are described from the Upper Cretaceous of Pylos (Greece). Their chronostratigraphic age is precisely constrained by strontium isotope stratigraphy, which allows an evaluation of their biostratigraphic and phylogenetic relationships with the type species of the three genera.

Shell architectures of the larger foraminiferal genera Cuvillierinella, Cyclopseudedomia, and Rhapydionina were studied by comparing topotypes of previously described species with new specimens retrieved from Late Cretaceous shallow-water carbonates of Pylos (Peloponnese, Greece), where the three genera are found in association. The megalospheric generation of each genus exhibits a distinctive shell shape in adult specimens (i.e., fan-shaped in Cyclopseudedomia, conical in Rhapydionina, and cylindrical in Cuvillierinella). Although their microspheric adults are similarly thin, flat, and discoidal, they can be identified at the genus level by means of a detailed structural analysis. Cuvillierinella shows the septula to be interrupted by a large preseptal space, while Cyclopseudedomia and Rhapydionina exhibit continuous, non-interrupted septula. In addition, Cyclopseudedomia presents only one row of medullar chamberlets, whereas Rhapydionina shows numerous medullar chamberlets distributed in a thick basal layer. Two new species, Cuvillierinella pylosensis and Rhapydionina fleuryi, are described. The former is a more complex taxon than the type species, C. salentina, while the latter corresponds to a more primitive species, R. liburnica. Strontium-isotope stratigraphy indicates an uppermost Campanian–lowermost Maastrichtian age for these new species. INTRODUCTION Many sedimentary rocks, particularly shallow-water limestones, cannot be disaggregated by common methods. Their fossil content has to be identified in thin sections where they occur in non-oriented, random sections (cuts). Moreover, in some groups of larger foraminifera the genera inhabiting the same environments are so similar in shell shape and structure that they can be distinguished only by a precise three-dimensional structural analysis. Such is the case for axially compressed alveolinaceans (Rhapydioninidae), which inhabited the uppermost part of the photic zone in restricted carbonate platform environments (Vicedo, 2008). Rhapydioninids show an early stage of planispiral or streptospiral growth that produces subglobular to lenticular involute shells. Specimens that retain the juvenile coiling mode into the adult stage may become evolute and flattened, discoidal, or peneropliform. Those that become uniserial develop cylindrical to conical shells. Coiled adults 1 Departament de Geologia, Universitat Auto`noma de Barcelona, 08193-Bellaterra, Spain 2 Institut fu¨r Erd- und Umweltwissenschaften, Universita¨t Potsdam, Germany 3 Dipartimento di Scienze della Terra, Universita` di Napoli ‘‘Federico II’’, Italy 4 Correspondence author: E-mail: [email protected]

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FIGURE 1. Geographic location and schematic log of the Late Cretaceous succession of Pylos, Peleponnese, southern Greece.

MATERIAL AND METHODS

STRONTIUM ISOTOPE STRATIGRAPHY

STUDIED AREA: LOCATION AND LITHOSTRATIGRAPHY

One of the problems most commonly encountered when studying Upper Cretaceous shallow-water carbonates is the relatively poor chronostratigraphic resolution attained by benthic foraminiferal biostratigraphy. Even though the succession of the biostratigraphic events can be usually worked out in detail, the definition of their chronostratigraphic age is often at best uncertain because there is generally little, if any, possibility to correlate the shallow-water sequences with the biostratigraphic zonations of ammonites or plankton that have been tied into the global chronologic time scale. Over the past two decades, strontium isotope stratigraphy (SIS) has become a widely used tool for geologic agedating and correlation (McArthur and Howarth, 2004), and its applicability in shallow water carbonate sequences has been demonstrated (Steuber, 2003). The Late Cretaceous, especially the late Turonian–Maastrichtian (90–65.5 Myr), is particularly favorable for SIS because the marine 87Sr/86Sr reference curve is very well-constrained across this time interval and is characterized by a very high gradient allowing for potential resolution of ,500 kyr. In this study we analyzed five rudist fragments from two horizons (Py-6 and Py-10) within the rotaliid interval at about 14 and 10 m respectively below the base of the rhapydioninid interval (Fig. 1). The best-preserved shells were selected after thorough diagenetic screening (procedure described in Frijia and Parente, 2008a, b). Geochemical analyses were performed at the Institut fu¨r Geologie, Mineralogie und Geophysik of the Ruhr-Universita¨ t (Bochum). Petrographic observations with a stereomicroscope and SEM revealed that, of the five shell fragments examined, three (Py-6D, Py-6G, Py-10B) show excellent

This study is based on the Late Cretaceous shallow-water carbonates of Pylos, in southern Peloponnese, Greece, where the three studied genera occur together and can be observed in the same thin-section. In addition, Pylos is the type locality of Cyclopseudedomia smouti Fleury (type species of the genus). The rhapydioninids appear irregularly in a 10-m-thick interval in the middle part of the studied succession (Fig. 1), where dolomitization has not completely obliterated the microfossils. This interval is constituted by dolostones and limestones with a wackestone-packstone texture in which larger foraminifera are associated with fragments of small, thin-walled rudists. The underlying interval (,20 m thick) consists of dolostones and limestones with rotaliids (‘‘Rotorbinella’’ scarsellai Torre) and rudist fragments, while the overlying interval (15 m thick) is also represented by dolomites and limestones, but with agglutinated foraminifera belonging mainly to the biserial conical genus Cuneolina. The Cretaceous section is overlain by a Paleogene carbonate succession containing a rich fauna of alveolinids and nummulitids. All the described species came from the samples Py-12 and Py-13 (Fig. 1; see Vicedo, 2008, for stratigraphic details). The rhapydioninids are associated with Scandonea sp., miliolids, and radiolitid rudists. For comparison with the Pylos species, we examined type specimens of Cuvillierinella salentina Papetti and Tedeschi from Poggiardo, Lecce, southern Italy (see Papetti and Tedeschi, 1965), and Rhapydionina liburnica (Stache) from Vra´bcˇe, Slovenia (see Bignot, 1971).

LATE CRETACEOUS RHAPYDIONINIDS

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FIGURE 2. Thin section and scanning electron micrographs of radiolitid rudist shells from Late Cretaceous of Pylos, Peleponnese, southern Greece. A Compact portion of the outer shell layer under parallel nichols; arrows point to microdrill scars;. B Same as A but under crossed nichols, showing the well-preserved, original fibrous-prismatic microstructure of the shell (specimen from sample Py-10B). C, D Compact portion of outer shell layer showing totally obliterated fibrous-prismatic microstructure under crossed nichols (specimen from sample Py-6A) and in the SEM (specimen from sample Py-10A).

preservation of the original prismatic microstructure (Figs. 2A, 2B), while two (Py-6A and Py-10A) show partial to complete alteration (Figs. 2C, 2D). The five shell fragments, plus the micritic matrix of sample Py-10, were analyzed for Sr-isotopes in order to compare the isotopic composition of petrographically pristine shell fragments with altered ones and to gain deeper insight into the diagenetic path. Another three shell fragments were analyzed for Fe, Mn, Mg, and Sr (Table 1). Diagenetic alteration of biogenic calcite usually results in a pattern of decreasing Sr accompanied by increasing 87 Sr/ 86Sr, Mn, and Fe (Al-Aasm and Veizer, 1986; McArthur, 1994). Decreasing 87Sr/86Sr with diagenesis has also been observed (Steuber and others, 2005). Although all of our analyzed shell fragments had low amounts of Mn and Fe, this is not necessarily indicative of good preservation (Steuber and others, 2005). The two shell fragments considered altered on the basis of petrographic observations yielded 87Sr/86Sr values slightly lower than the best-

preserved ones (Table 1). The micritic matrix of sample Py10 had the lowest 87Sr/86Sr value, which reinforces the hypothesis that, in the studied section, the diagenetic path from pristine shells to altered shells to micrite is one of diminishing 87Sr/86Sr ratios. A similar diagenetic pattern has been documented by Steuber and others (2005) for Upper Cretaceous rudist limestones from Brac Island (Croatia). Samples Py-6 and Py-10 were collected from two levels only 4 m apart and there is no sedimentological evidence of any significant gaps in-between. For the purpose of SIS, these two samples can be considered as representative of the same stratigraphic level. Internal consistency of the Sr isotope ratios of different samples from the same stratigraphic level is considered a very strong argument for good preservation (McArthur, 1994). The 87Sr/86Sr values of the three shell fragments selected as pristine by petrographic and geochemical screening are within analytical uncertainty (Table 1), further reinforcing the hypothesis that they preserve the original Sr-isotope signature of seawater.

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TABLE 1. Sample

Elemental concentrations, Sr-isotope ratio, and SIS age of the material from the Late Cretaceous of Pylos, Greece. See text for explanation. Component

Py-6A* Py-6D Py-6G Py-10A* Py-10B Py-10M mean

rudist rudist rudist rudist rudist micrite

87

Sr/86Sr

0.707709 0.707726 0.707721 0.707706 0.707733 0.707663 0.707727

6 2 s.e. (*1026)

Fe (ppm)

Mn (ppm)

Sr (ppm)

Mg (ppm)

6 6 6 1 6 6 7

8 2 1

1 1 0,2

815 1060 1071

1777 1735 1172

87

Min

Age (Ma)

Max

70.63

71.14

71.71

86

* Altered shells. The numerical age has been calculated from the mean Sr/ Sr value of the three pristine shells (in bold character).

The numerical age of the samples was calculated from the look-up table of McArthur and others (2001 [version 4: 08/ 04]) that is tied to the geological time scale of Gradstein and others (2004). The 87Sr/86Sr mean value of 0.707727, obtained from the three pristine rudist fragments, translates into a ‘‘preferred’’ numerical age of 71.14 Ma (Table 1). This age is within the uppermost Campanian and correlates with the lower part of Nostoceras hyatti ammonite zone and with the middle part of the Globotruncana gansseri planktic foraminiferal zone. The first level with rhapydioninids occurs 10 m above Py10. There is no sedimentological evidence for the existence of a significant hiatus between these horizons, and taking into account the error bar on the SIS numerical age (see Table 1 and Fig. 2), an uppermost Campanian–lowermost Maastrichtian age is inferred for the rhapydioninid-bearing carbonates. ARCHITECTURE OF STUDIED GENERA GENUS CUVILLIERINELLA Type species: Cuvillierinella salentina Papetti and Tedeschi, 1965.

Description. Test free, dimorphic, porcelaneous; ovate, discoidal, or crosier-shaped. Megalospheric forms start with spherical proloculus with flexostyle followed by chambers in streptospiral arrangement; shells tend to stabilize their axis of coiling throughout early ontogeny resulting in involute planispiral with ovate axial section.

Adult shells uncoil and become crosier-shaped. Microspheric forms have small glomerulus followed by chambers spirally arranged as in A-forms; however, adult shells typically assume flattened peneropliform to discoidal shape. Endoskeleton may be irregular, low-density. Chamber lumen divided into cortical and medullar chamberlets not clearly differentiated in size, but the former appears to be slightly larger than the latter. Septula continuous between chambers, not reaching next septum except in peripheral, external part of shell (Fig. 3). Preseptal space well developed. Cuvillierinella pylosensis Vicedo and Caus, n. sp. Figs. 4.1–4.13, 5.1–5.5 1974 Raadshoovenia salentina (Papetti and Tedeschi); Fleury, pl. 50, figs. 1–14; pl. 52, figs. 4–6.

Etymology. From the village of Pylos. Holotype. PUAB-82007 (axial section, Fig. 4.7) from uppermost Campanian–lowermost Maastrichtian, upper part of Globotruncana gansseri planktic foraminiferal zone. Deposited in the micropaleontological collection of Departament de Geologia, Universitat Auto`noma de Barcelona, Spain. Description of holotype. Test ovoid, slightly streptospiral; megalosphere diameter 140 mm; endoskeleton apparent in second whorl; equatorial diameter 0.8 mm. Paratypes. PUAB-82008, PUAB-82009, PUAB-82010, PUAB-82011, and PUAB-82012 (Figs. 4.3, 4.6, 4.11, 4.13, and 5.5 respectively).

FIGURE 3. Cuvillierinella Papetti and Tedeschi. 1 Drawing of internal structure of two successive adult chambers (not to scale). 2 Transmitted light microphotograph of part of Cuvillierinella pylosensis n. sp. in thin section (from Fleury 1974, pl. 52, fig. 5). 3 Sketch of external view of Cuvillierinella (B-form); grey square (A) indicates area of previous image. Key to abbreviations: ap 5 aperture, ap f 5 apertural face, bl 5 basal layer, c chl 5 cortical chamberlets, E 5 embryo, f 5 flexostyle, flo 5 floor, fo 5 foramina, G 5 glomerulus, m chl 5 medullar chamberlet, prp 5 preseptal space, rpi 5 residual pillars, s 5 septum, sl 5 septulum.


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FIGURE 4. Cuvillierinella pylosensis n. sp. from uppermost Campanian–lowermost Maastrichtian of Pylos, Peleponnese, southern Greece: transmitted-light micrographs of megalospheric generation in thin sections of cemented carbonates (scale bars 5 0.5 mm). See Figure 3 caption for key to abbreviations. 1 Oblique section close to the axial plane. 2–4, 6, 13 Slightly oblique axial sections; note the presence of the flexostyle in 3 and 6. 5, 7–9 Axial sections. 10 Longitudinal section of the uniserial stage. 11 Equatorial section. 12 Tangential section of three successive chambers.

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FIGURE 5. Cuvillierinella pylosensis n. sp. from uppermost Campanian–lowermost Maastrichtian of Pylos, Peleponnese, southern Greece: transmitted-light micrographs of microspheric generation in thin sections of cemented carbonates (scale bars 5 0.5 mm; note large size of specimens). See Figure 3 caption for key to abbreviations. 1 Oblique off-center section. 2, 3 Oblique off-center sections showing wide preseptal space. 4, 5 Axial sections of adult discoidal shell fragments.


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FIGURE 6. Cuvillierinella salentina Papetti and Tedeschi from middle Campanian of Poggiardo, Lecce, southern Italy: transmitted-light micrographs of topotypes in thin sections of cemented carbonates, (scale bars 5 0.5 mm). See Figure 3 caption for key to abbreviations. 1–6 Megalospheric generation: 1–3, axial sections (note the 2 or 3 early streptospiral whorls of undivided chambers); 4–5, equatorial sections (note the last chambers tending to acquire the uniserial habit); 6, detail of the uncoiled stage of growth in a specimen of Cuvillierinella. 7–9, microspheric generation: 7, 8, axial sections showing well-preserved glomerulus; 9, oblique section close to equatorial plane showing uniserial arrangement of last chambers.

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FIGURE 7. Cyclopseudedomia Fleury. 1 Drawing of internal structure of two successive adult chambers (not to scale). 2 Transmitted light photomicrographs of thin-sections (pictures A, B and C). 3 Sketch of external view; lines A, B and C indicate locations of areas shown in preceding image. See Figure 3 caption for key to abbreviations.

Type locality. Citadel of Pylos (Peloponnese, Greece) (36u54941.820 N, 21u41918.110 E). Type level. Uppermost Campanian–lowermost Maastrichtian (upper part of Globotruncana gansseri planktic foraminiferal zone). Diagnosis. This species exhibits strong dimorphism (a ratio of 1:5 between the maximum diameter of A and B forms). Its megalosphere is typically 130–160 mm (exceptionally 200 mm) in diameter; about half of which is covered by a long flexostyle. The involute megalospheric nepiont consists of one to two streptospiral whorls of undivided chambers followed by two planispiral whorls. Five to six chambers compose each planispiral whorl. These coiled juveniles have a maximum diameter of 0.9–1.1 mm. Adult A-forms measured along the uncoiled part of the shell can reach a length of 1.7 mm. The microspheric generation starts with a glomerulus followed by spirally arranged chambers which tend to become flattened and flabelliform in the latest stages of growth. Even though the B-form may attain a diameter of 10 mm, being very flat with a small proloculus makes it very difficult to find a perfectly centered section. Such sections are scarce in our material, but Fleury (1974) illustrated a well-preserved equatorial section (Fleury, 1974, pl. 52, fig. 5) from the same stratigraphic level. The total number of chamberlets per chamber in the third whorl is 9–10. The size of the cortical chamberlets measured in a plane parallel to the periphery of the shell is 40–50 mm, whereas the size of the medullar chamberlets is about 30–40 mm. The preseptal space is well developed and occupies one third to one half of the total space of the chamber. Discussion. The new species differs from the type-species C. salentina (Fig. 6), by its strong dimorphism. Cuvillierinella salentina exhibits little or no dimorphism while in C. pylosensis n. sp. the maximum diameter ratio of between the A and B forms is 1:5. The megalosphere diameter is larger in C. pylosensis (130–160 mm) than in C. salentina (80– 120 mm). Cuvillierinella pylosensis shows a reduction of its streptospiral nepiont compared with that of C. salentina (see Figs. 4 and 6). Endoskeleton elements appear earlier in C. pylosensis than in C. salentina. All of these characteristics

suggest that C. pylosensis is a more evolved species than C. salentina. This hypothetical phylogenetic relation is confirmed by the age of the type levels of these two species. In fact the type locality of C. salentina, considered upper Santonian in age by Papetti and Tedeschi (1965) and upper Campanian (lower Maastrichtian?) by De Castro (1990), has been recently dated as middle Campanian (76.6 6 0.6Ma) by SIS (Schlu¨ter and others, 2008). A middle Campanian age is consistent with the occurrence of discontinuous patches of limestones with uppermost Campanian ammonites unconformably overlying the limestones with C. salentina (Giudici and others, 1994). The presence of a long flexostyle in the embryo of C. pylosensis is similar to that of Murciella cuvillieri Fourcade, 1966. Nevertheless, C. pylosensis shows an irregular, lowdensity endoskeleton with few chamberlets per chamber, while M. cuvillieri shows a regular disposition of the skeleton elements, resulting in numerous chamberlets closely spaced. Further, C. pylosensis preserves an initial streptospiral coiling with one or two initial whorls of undivided chambers as in C. salentina, whereas M. cuvillieri exhibits a planispiral or a slightly streptospiral coiling in its early stages. GENUS CYCLOPSEUDEDOMIA Type species: Cyclopseudedomia smouti Fleury, 1974.

Description. Test free, large, dimorphic, flat, flabelliform to discoid shape. Chambers elongate, and their arrangement varies from planispiral to peneropliform or annular. A-form consists of very large spherical megalosphere followed by flexostyle. Elongation of chambers following embryo increases rapidly, and shell becomes peneropliform in earliest ontogenetic stages. Adult chambers do not reach annular growth. Microspheric nepiont is small and poorly known, but B-forms can be distinguished by their large-size. Flattened, peneropliform adult B-form acquires annular chamber arrangement in latest stages of growth. Shell structure consists of septula and floors, which subdivide cambers lumen into cortical and medullar chamberlets, respectively. Subcylindrical cortical chamber-


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FIGURE 8. Cyclopseudedomia smouti Fleury from uppermost Campanian-lowermost Maastrichtian of Pylos, Peleponnese, southern Greece: transmitted-light micrographs of megalospheric topotypes in thin sections of cemented carbonates (scale bars 5 0.5 mm). See Figure 3 caption for key to abbreviations. 1 Slightly oblique equatorial section of peneropliform specimen. 2, 3, 6–8 Axial sections showing eccentric protuberance produced by large megalosphere. 4, 5 Oblique center sections close to equatorial plane.

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FIGURE 9. Cyclopseudedomia smouti Fleury from uppermost Campanian–lowermost Maastrichtian of Pylos, Peloponnese, southern Greece. Transmitted-light micrographs of topotypes in thin sections of cemented carbonates (scale bars 5 0.5 mm). See Figure 3 caption for key to abbreviations. 1–6 Megalospheric generation: 1, slightly oblique axial section of two successive chambers showing wide residual pillars; 2, slightly oblique axial section showing alignment of medullar chamberlets; 3, 4, oblique sections; 5, 6 oblique sections close to axial plane; image 6 displays eccentric protuberance produced by megalosphere and the aligned medullar chamberlets of successive chambers. 7, 8 Microspheric generation: 7, offcenter section parallel to axial plane of large discoidal shell showing medullar chamberlets increasing in obliquity; 8, oblique section.

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FIGURE 10. Rhapydionina Stache. 1 Drawing of internal structure of two successive adult chambers (not to scale). 2 Transmitted-light micrographs of microspheric Rhapydionina liburnica in thin-sections. 3, Sketch of the external view of Rhapydionina (B-form); A and B denote sections shown in preceding image. See Figure 3 caption for key to abbreviations.

lets disposed in thick external row. Medullar chamberlets generally arranged in single row in central area of chamber (rarely two or more in last stages of growth). Cortical chamberlets larger than medullar ones, but difference is less evident than in Rhapydionina (see below). Poorly developed preseptal space connects chamberlets within the same chamber. Septula continuous between chambers, not interrupted by preseptal space. Residual pillars short, but large compared to chamberlet diameter (Fig. 7). Cyclopseudedomia smouti Fleury, 1974 Figs. 8.1–8.8, 9.1–9.8 1974 Cyclopseudedomia smouti Fleury; pl. 51, figs. 1–12; pl. 52, figs. 1–4

Description. Dimorphism pronounced with a 1:5 ratio between maximum diameters of A and B forms. A-form has voluminous megalosphere (300–400 mm diameter) with short, wide flexostyle covering about one quarter of megalosphere’s periphery. The large-size megalosphere produces an eccentric protuberance in the shell. Flexostyle followed by chambers arranged in spiral in no more than one whorl. Adult specimens peneropliform, up to 3 mm in diameter. B-forms annular, discoidal, may reach 15 mm in diameter. Basic structure corresponds to that described for genus. Cortical chamberlets with mean diameter of 45–60 mm regularly distributed in external row. Medullar chamberlets varying 30–50 mm in diameter form a row in center of chamber. Increasing chamber size at final stages of annular growth may result in an additional row of medullar chamberlets. Discussion. Three species have been ascribed to the genus Cyclopseudedomia: C. smouti, ‘‘C.’’ hellenica Fleury, 1979a and ‘‘C.’’ klokovaensis (Fleury, 1979a). In the present work the material from the type locality of ‘‘C.’’ hellenica has not been analyzed, but specimens figured by Fleury (1979b, pl. 1, figs. 1–23) illustrate some characteristics that reveal structural differences with the genus Cyclopseudedomia (type species C. smouti). For example, the low-density endoskeleton and the wide preseptal space (see Fleury 1979b, pl. 1, figs. 1–4, 21, 22) exhibited by ‘‘C.’’ hellenica suggest a close relationship with Cuvillierinella rather than

Cyclopseudedomia. The position of the septula is crosswiseoblique in ‘‘C.’’ klokovaensis (see Fleury 1979a, pl. 4, figs. 1–18,) and parallel in Cyclopseudedomia. Thus, generic placement of ‘‘C.’’ hellenica and ‘‘C.’’ klokovaensis needs further investigation. GENUS RHAPYDIONINA Type species. Peneroplis liburnica Stache, 1889

Description. Test porcelaneous, dimorphic, cylindroconical to fan-shaped. Megalospheric forms characterized by flexostylic embryo followed by chambers with streptospiral or planispiral arrangement in earliest stages of growth, later adding uniserial stage consisting of numerous cylindrical chambers. Microspheric forms exhibit poorly developed spiral stage; adults large with arched chambers in flaring, peneropliform arrangement; structurally, radial septula separate cortical chamberlets in peripheral part of chamber lumen. Solid basal layer and numerous irregularly disposed medullar chamberlets developed in central part of shell. Shape and size of cortical and medullar chamberlets show great differences. Cortical chamberlets large and elongate rectangular; medullar ones small, subcircular cavities. Septula continuous from one chamber to next, not interrupted by preseptal space that is restricted to central part of chamber (Fig. 10). Rhapydionina fleuryi Vicedo and Caus, n.sp. Figs. 11.1, 11.9 1973 Rhapydionina liburnica (Stache); Hamaoui and Fourcade, pl. 10, figs. 3, 8.

Etymology. In honor of Prof. Jean-Jacques Fleury of Lille, France, who worked for many years on the Rhapydioninidae. Holotype. PUAB-82013 (Fig. 11.1) from uppermost Campanian–lowermost Maastrichtian, upper part of Globotruncana gansseri planktic foraminiferal zone. Deposited in the micropaleontological collection of Departament de Geologia, Universitat Auto`noma de Barcelona, Spain.

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FIGURE 11. Rhapydionina fleuryi n. sp. from uppermost Campanian–lowermost Maastrichtian of Pylos, Peloponnese, southern Greece. Transmitted-light micrographs of specimens in thin sections of cemented carbonates (scale bar 5 0.5 mm). See Figure 3 caption for key to abbreviations. 1–7 Megalospheric generation: 1–3, oblique-centered sections showing small proloculus (smaller than that of megalospheric R. liburnica); 4–7, longitudinal sections of uniserial stage. 8, 9 Oblique off-center sections of microspheric generation.


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FIGURE 12. Rhapydionina liburnica Stache from upper Maastrichtian, Vra´bcˇe, Slovenia. Transmitted-light micrographs of specimens in thin sections of cemented carbonates (scale bars 5 0.5 mm). See Figure 3 caption for key to abbreviations. 1–3, 5 Megalospheric generation: 1, section showing early coiled stage followed by uncoiling into uniserial stage with short cylindrical chambers. 2, 3, 5, sections showing early coiled to late uniserial stages (note the length of the latter stage in image 5). 4, 6 Microspheric generation: 4, transverse section. 6, fan shape that distinguishes microspheric from megalospheric Rhapydionina (note preseptal space restricted to central part of chamber, endoskeleton in central area).

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Description of holotype. Test conical, streptospiral to uniserial; proloculus diameter 40 mm; test length 1.6 mm. Paratypes. PUAB-82014 (Fig. 11.2) and PUAB-82015 (Fig. 11.9). Type locality. Citadel of Pylos (Peloponnese, Greece; 36u54941.820 N, 21u41918.110 E). Type level. Uppermost Campanian–lowermost Maastrichtian, upper part of Globotruncana gansseri planktic foraminiferal zone. Diagnosis. Dimorphic. Megalospheric forms are represented by small cylindrical to conical shells, which may reach 1.7 mm in length and 0.7 mm in diameter. Small megalospheres (40–50 mm diameter) are followed by a long flexostyle and two streptospiral whorls of undivided chambers. A maximum of 7–10 low-cylindrical, uniserial chambers constitute the adult shells. Microspheric forms are fan-shaped and can reach up to 2 mm in length and 3 mm in width; those containing the proloculus and the earliest stages of growth are scarce in thin sections because their large and very thin tests are usually fragmented. Endoskeleton elements start at the first uncoiled chamber, and the cortical and medullar chamberlets follow the same structural pattern of the type species. Cortical chamberlets have 40–60 mm in diameter, while medullar ones have a maximum diameter of 40 mm. Discussion. Rhapydionina fleuryi differs from R. liburnica (Fig. 12), which is considered to be a late Maastrichtian species (Bilotte, 1998), by the dimensions of both shell and megalosphere. Maximum dimensions of megalospheric shells of R. liburnica are 1.8 mm width and 7 mm length with 180–320 mm diameter megalosphere, whereas those of R. fleuryi are 0.7 mm width and 1.7 mm length with 40– 50 mm megalosphere. The initial coiled stage of growth is more developed in R. fleuryi and its structure of fewer elements appears later in ontogeny. These characteristics suggest that R. fleuryi is the more primitive form, as would be expected from their biostratigraphic order. The inferred phylogeny agrees with their respective biostratigraphic ages. CONCLUSIONS The megalospheric generations of Cuvillierinella, Cyclopseudedomia, and Rhapydionina are readily distinguished by shape. Cuvillierinella is crosier-shaped and its chamber arrangement varies from streptospiral to planispiral before uncoiling. Cyclopseudedomia constructs flat shells with very large proloculi followed by coiled, peneropliform chambers. Rhapydionina has a cylindro-conical shape defined by a short coiled stage followed by a uniseries of numerous short-cylindrical chambers. The microspheric generations of the three genera similarly tend to develop thin, flattened, discoidal shells during their ontogeny. These B-forms are characterized by spiral, flaring peneropliform to annular chamber arrangements. Cuvillierinella presents a poorly developed and irregular endoskeleton. The septula are interrupted by a large preseptal space, and they do not reach the next septum, except in the interiomarginal part of the chamber. There is no significant difference between cortical and medullar chamberlets. Cyclopseudedomia has continuous, non-interrupted septula, which individualize a thick external row of

cortical chamberlets. Medullar chamberlets, smaller than cortical ones, are disposed in a row in the central area of the shell. In Rhapydionina the radial septula form a row of large, rectangular cortical chamberlets in the peripheral part of the chamber, while the numerous, small, subcircular medullar chamberlets are distributed irregularly in a central solid basal layer. Septula are not interrupted by the preseptal space, which is restricted to the central part of the chamber. Endoskeleton elements of all three genera continue from one chamber to the next. The architectural characteristics of Cuvillierinella pylosensis n. sp show that this species is more evolved than the typespecies, C. salentina. Conversely, Rhapydionina fleuryi n. sp. is more primitive than R. liburnica. Strontium isotope chronostratigraphy places the type level of C. pylosensis and R. fleuryi in the uppermost Campanian–lowermost Maastrichtian. Their phylogenetic relationship, inferred from the architectural characters, agrees with ages indicated by Srisotope stratigraphy. This opens the possibility of using the rhapydioninids to build a Late Cretaceous biozonation for the Tethyan restricted shallow-water carbonate facies, which could then be correlated with the open-marine biozonation based on lamellar-perforate orbitoidal foraminifera. ACKNOWLEDGMENTS We extend our sincere thanks to Prof. Lukas Hottinger (Basel) for his very useful comments about rhapydioninids, and to Dr. Katica Drobne (Lujbiana, Sloveny) for providing us with material from Slovenia. Financial support for this investigation in the frame of the projects CGL2006-02899/BTE and CGL2009-08371 (subprograma BTE) is gratefully acknowledged. REFERENCES AL-AASM, I. S., and VEIZER, J., 1986, Diagenetic stabilization of aragonite and low-Mg calcite. I. Trace elements in rudists: Journal of Sedimentary Petrology, v. 56, p. 763–770. BIGNOT, G., 1971, Contribution a l’e´tude des espe`ces liburniennes des genres Rhapydioninia Stache 1913 et Rhipidionina Stache 1913: Revue de Micropaleóntologie, v. 13, p. 222–236. BILOTTE, M. (coord.), 1998, Cretaceous biochronostratigraphy 2 larger benthic foraminifera, in Graciansky de, P.-C., Hardenbol, J., and Vail, P. R. (eds.), Mesozoic and Cenozoic sequence stratigraphy of European basins. Society of Economic Paleontologists and Mineralogists, Special Publication 60, Chart 5. DE CASTRO, P., 1990, Osservazioni paleontologiche sul Cretacico della localita´-tipo di Raadshoovenia salentina e su Pseudochubbina n. gen.: Quaderni dell’Accademia Pontaniana, v. 10, p. 116. FLEURY, J.-J., 1974, Contribution a la connaissance des Rhapydionininae (foraminife`res, Alveolinidae) Cre´tace´s: Geóbios, v. 7, p. 307–332. ———, 1979a, Le genre Murciella (foraminife`re, Rhapydionininae), dans le Cre´tace´ supe´rieur de Gre`ce (zone de Gavrovo-Tripolitza): Geóbios, v. 12, p. 149–185. ———, 1979b, A propos d’une nouvelle espe`ce du Cre´tace´ terminal de Gre`ce. Place du genre Cyclopseudedomia parmi les Rhapydionininae (foraminife`res, Alveolinidae): Revue de Micropaleóntologie, v. 22, p. 19–28. ———, and FOURCADE, E., 1990, La super-famille Alveolinacea (foraminife`res): syste´matique et essai d’interpretation phylogeńe´tique: Revue de Micropaleóntologie, v. 33, p. 241–268. FOURCADE, E., 1966, Murciella cuvillieri n.gen. n.sp. nouveau foraminife`re du Seńonien supe´rieur du sud-est de l’Espagne: Revue de Micropaleóntologie, v. 9, p. 147–155.


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Received 5 March 2010 Accepted 14 July 2010