Geologica Romana 40 (2007), 215-225
NEW INSIGHT ON ARCHITECTURE AND MICROSTRUCTURE OF ELLIPSACTINIA AND SPHAERACTINIA (DEMOSPONGES)
FROM THE GARGANO PROMONTORY (SOUTHERN ITALY)
Antonio Russo* & Michele Morsilli**
* Dipartimento del Museo di Paleobiologia e dell’Orto Botanico, Università di Modena e Reggio Emilia - russo@unimo.it
** Dipartimento di Scienze della Terra, Università di Ferrara
ABSTRACT - Ellipsactinia and Sphaeractinia are two groups of organisms which represent very important stratigraphic markers, especially for the Jurassic and the Cretaceous, becoming the principal constituents of carbon- ate platform margins of these periods. Furthermore, because they lived exclusively in the Mesozoic Tethys sea, we consider them as good palaeogeographic and palaeoclimatic fossils. They were very abundant in Late Jurassic and Valanginian in the Adriatic and Apulian carbonate platforms.
The architecture and microstructure of these two groups are completely different. Ellipsactinia has a simpler architecture than Sphaeractinia, which exhibits an organization of lamellae and radial channels termed “dry-stone wall”, and the presence of astrorhizae-like structures. Also the microstructure is different. In Ellipsactinia there is a “water jet” (clinogonal) pattern of fibers, whereas in Sphaeractinia the fiber arrangement is spherulitic. In both the genera, rare, isolated and scattered, monaxon spicules are present.
The skeletal organization and the types of microstructures allow us to ascribe these two genera to Demospongiae.
KEY WORDS: Ellipsactinia, Sphaeractinia, Demosponges, microstructure, Mesozoic, Apulia.
INTRODUCTION
Ellipsactinia and Sphaeractinia are two groups of organisms very similar each to other, and they represent very important stratigraphic markers, mainly for the Jurassic and the Cretaceous, periods when they became the principal builders of carbonate platforms.
Furthermore, their distribution, limited to the Mesozoic Tethys, allow us to consider these organisms as excellent paleoclimatic and paleogeographic fossils. In Italy they were very abundant from Sicily to Friuli in Late Jurassic and Valanginian times.
Hill and Wells (in Moore, Treatise on Invertebrate Paleontology, Part F, 1956) include, with some reserva- tions, the genus Ellipsactinia in the family Hydractinidae Agassiz, 1862, and the genus Sphaeractinia in the fami- ly Actinostromatidae Nicholson, 1886, order Stromato- poroidea.
From an architectural and microstructural point of view, anyhow, these two groups, to which the two genera have been assigned, exhibit different peculiarities.
At present, the Hydractinidae are attributed to the Coelenterata, the gastric cavity of which makes four radi- al canals, the colonies are mainly incrusting with the caulomes rising from a chitinous or calcareous mat of tangled hydrorhizae with periderm. The stromatoporoids on the contrary, previously ascribed to Hydrozoa, are now considered, or at least a large part of them, as per- taining to the demosponges. Very interesting investiga- tions on Stromatoporoidea systematics have been made by Stearn (1971, 1974); Wood (1987), Reitner (1992);
and recently by Stock (2002) and Leinfelder et al.
(2005), which include, tout court, Ellipsactinia and Sphaeractinia in the stromatoporoid group.
The aim of this paper is to describe the micro- architecture and microstructure of Ellipsactinia and Sphaeractinia in order to provide a more precise system- atic placement for these two genera.
Previous works
The genera Ellipsactinia and Sphaeractinia were established in 1878 by G. Steinmann, and included by the author in family Corynidae. This family comprises other genera such as Hydractinia Van Beneden, Thalaminia Steinmann, Labechia Milne Edwards et Haime, Stromatopora Goldfuss, Loftusia Brady, Parkeria Carpenter, Cylindrohyphasma Steinmann, and Porosphaera Steinmann. The specimens described by Steinmann come from Stramberg (Moravia) and are Tithonian in age.
Initially, the genera Ellipsactinia and Sphaeractinia were monotypic, including only E. ellipsoidea and S.
diceratina, but Zittel (1879), in his Handbuch der Paläontologie, ascribed Ellipsactinia to the family Stromatoporidae Nicholson et Murie; the Stromato- poridae together with the families Milleporidae Mosley and Stylasteridae Gray constitute the suborder Hydrocorallinae Mosley. In contrast, the genera Hydractinia Van Beneden, Thalaminia Steinmann, Sphaeractinia Steinmann, Parkeria Carpenter, and, with some doubs, Loftusia Brady, were included in the subor- der Tubularina Ehrenberg.
Also Portis (1881) ascribed the same genera listed by Steinmann to Hydrocorallinae Hydrozoa, including two new species, Ellipsactinia fortisi and Sphaeractinia pedemontana, from the Upper Jurassic of Argentera, near the Stura Valley (Cuneo, Northern Italy).
Hoernes (1884) assigned the two named genera to the
family Stromatoporidae, suborder Hydrocorallinae, order Tubulariae. Nicholson (1886) listed Sphaeractinia and Ellipsactinia among the Actinostromatidae, order Stromatoporoidea Nicholson and Murie, 1878.
Steinmann (1888) described a new species of Sphaeractinia without providing a specific name; this species was later redescribed and named by Canavari (1893) as Sphaeractinia steinmanni.
The family Ellipsactinidae, order Stromatoporoidea Nicholson and Murie, class Hydroida has been estab- lished by Canavari (1890), who included in this family the genera Ellipsactinia and Sphaeractinia. In the first genus Canavari (1890) included various species, among which are some established by himself: E. ellipsoidea Steinmann, 1878, E. portisi Canavari, 1893, E. tyrrheni- ca Canavari, E. micropora Canavari, E. caprense Canavari, E. africana Canavari, E. polypora Canavari and E. ramosa Canavari. In the second genus he includ- ed, besides the already known species S. diceratina Steinmann, S. pedemontana Canavari, S. steinmanni Canavari, also the new species S. dicotoma Canavari.
Osimo (1910), ascribed the genera Ellipsactinia and Sphaeractinia to Hydrozoa, particularly Tabularia group.
Kühn (1927, 1939) assigned the Sphaeractiniae to stromatoporids (at that time considered Hydrozoa), strictly related to Disjectoporidae, and established the new order Sphaeractinoidea.
Steiner (1932), on the contrary, included the family Ellipsactinidae in the order Stromatoporoidea.
Lecompte (1951, 1952) included Ellipsactiniae and Sphaeractiniae in the family Actinostromatidae, order Stromatoporoidea.
In 1956, Hill & Wells, in the “Treatise on Invertebrate Paleontology”, included tentatively the genus Ellipsactinia in the family Hydractiniidae Agassiz, 1862, order Hydrozoa, whereas the genus Sphaeractinia was included, also doubtfully, in the family Actino- stromatidae Nicholson, 1886, order Stromatoporoidea.
Bachmayer & Flügel (1961) ascribed the genera Ellipsactinia (type species E. ellipsoidea, Steinmann, 1878) and Sphaeractinia (type species S. diceratina Steinmann, 1878) to the family Sphaeractinidae Waagen
& Wentzel 1887, order Sphaeractinoidea Kühn, 1927, class Hydrozoa Owen, 1843. Within this order they included also the family Actinostromariidae Hudson, 1955, now assigned to class Demospongiae Sollas, 1875, phylum Porifera Sollas, 1875.
Babayev (1973), as regards these two genera, followed the classification of Steinmann.
Grubić (1959), besides listing all the sphaeractinids known at that time, established a new species, Sphaeractinia cylindrica, collected by himself in west- ern Serbia, Tithonian-Valanginian in age.
In 1961, Grubić revised the Sphaeractiniae, splitting them into Triassic, Liassic and Paleogene.
The Triassic listed species are:
Lithopora koehneni Tornquist, 1900, a species that subsequently Dehorne (1920) and Steiner (1932) assigned to the genus Ellipsactinia Steinmann
Stromactinia triassica Vinassa de Regny, 1901 Circopora sp. (following Grubić it is a synonym of C.
caucasica)
Circopora caucasica Moiseew, 1944 Sphaeractinia rothpletzi Leuchs, 1931 Sphaeractinia kinzigensis Leuchs, 1931
According to Grubić, these last species show morpho- logic features and microstructures that are quite different from true Sphaeractiniae; again, a restudy of the type material appears necessary. Nevertheless Ellipsactinia bonomi Vialli is considered as strikingly different from all the other fossil Hydrozoa, so it belongs to Anthozoa, close to Alcyonaria, Stolonifera.
In the Liassic group, Grubić included: Ellipsactinia ellipsoidea Steinmann, Ellipsactinia caprense Canavari, Ellipsactinia tyrrhenica Canavari, Ellipsactinia africana Canavari, and Ellipsactinia bonomi Vialli, 1938. In this group G. Meneghini (1884) and Canavari (1893) includ- ed taxa found in Tunisia, such as Ellipsactinia ellip- soidea Steinmann, E. caprense Canavari, E. tyrrhenica Canavari, and E. africana Canavari.
Among the Paleogene sphaeractinids, Capeder (1898) described Ellipsactinia gassino (from the Calcare di Gassino - Gassino Limestone), Ellipsactinia ponzone (from the Calcare di Ponzone - Ponzone Limestone) and Ellipsactinia prasco (from the Calcare di Prasco - Prasco Limestone), considering them as the last anomalous taxa of the Sphaeractiniae family. The aspect of these three forms should be the same of the Sphaeractinia, never observed in Ellipsactinia. Nevertheless Capeder’s Sphaeractinia species show characters not seen in any Sphaeractiniae known until that time.
In 1959, Grubić established a new Sphaeractinia species: Sphaeractinia poljaki; this species was revised later by him (Grubić, 1983a). This taxon was recorded for the first time by J. Poljak in 1938 as Sphaeractinia sp.
In the same paper Grubić (1959) points out the preva- lence of these forms in Tithonian-Valanginian deposits and debates the origin of these two genera from a com- mon ancestor in the stromatoporoids. Furthermore, the author divides the Ellipsactiniae and the Sphaeractiniae on the basis of different morphologic features.
Geological and stratigraphical setting
The study fauna comes from samples collected in the Monte Sacro limestone: a stratigraphical unit of Upper Jurassic-Berriasian age cropping out in the Gargano Promontory (Apulia, southern Italy) (Fig. 1).
The Gargano Promontory, mainly consists of carbon- ate rocks, belongs to the Apulia Carbonate Platform, a major Mesozoic paleogeographic element southern mar- gin of the Tethys Ocean (Bernoulli, 1972; D’Argenio, 1976; Bosellini et al., 1999).
Structurally it is a part of the foreland of the Apennine chain, broadly deformed into a gentle anticline with a WNW-ESE axis (Martinis, 1965). This area is also affected by numerous faults with various trends and kinematics (Funiciello et al., 1992; Bertotti et al., 1999;
Brankman & Aydin, 2004). The most prominent feature is the Mattinata fault, a regional E-W shear zone that crosses the entire Gargano area.
The Gargano area, together with the Maiella Mountain, is the only place where the transition between platform and slope-to-basin facies crops out (Bosellini et al., 1999). In other areas, the eastern margin of this plat- form lies offshore under the Adriatic Sea, about 20 to 30 km from the present coastline (De Dominicis &
Mazzoldi, 1989).
The Jurassic to Eocene successions of the Gargano were divided into different second-order stratigraphic
sequences, bounded by unconformities of different types and origins, that represents various depositional envi- ronments (Bosellini et al., 1993; Morsilli & Bosellini, 1997; Bosellini et al., 1999; Bracco Gartner et al., 2002;
Conti et al., 2005).
For the purpose of present paper we consider only the lowest sequence called Monte Sacro Sequence (Fig. 2, Morsilli & Bosellini, 1997) spanning in age from the Callovian p.p. to the Valanginian p.p., and particularly the Monte Sacro Limestones, which corresponds to the bioconstructed margin of the Apulia Carbonate Platform.
This unit, Oxfordian p.p. to Berriasian in age, crops out
Fig. 1 - Facies distribution of the Gargano Promontory during the Early Cretaceous. Symbols: 1) inner platform facies; 2) oolitic shoals; 3) Ellipsactinia margin (Monte Sacro Limestones); 4) slope to basin facies (slightly modified after Morsilli & Bosellini, 1997).
Fig. 2 - Schematic depositional profile and facies belts. From left to right listed the facies association from F1 to F8. Samples collected mainly in the F5 (modified after Morsilli & Bosellini 1997).
in a narrow and arcuate belt from M. d'Elio to Mattinata (Fig. 1).
Monte Sacro Limestones consists of massive wacke- stones with Ellipsactinia, Sphaeractinia and, in some areas, stromatactis-like features. The outcropping thick- ness can be estimated to be about 300 m (the base is not exposed). This formation has been referred to a “bank reef” (Mattavelli & Pavan, 1965; Martinis &
Pavan,1967; Cremonini et al., 1971). The same facies has been interpreted as an “external margin” on the Capri Island (Barattolo & Pugliese, 1987) and as repre- senting a “slope environment” in the Marsica area (Colacicchi & Praturlon, 1965; Colacicchi, 1967).
Morsilli & Bosellini (1997) in a sedimentological study divided the Monte Sacro Sequence in 8 facies associations, where Monte Sacro Limestones corre- sponds mainly to the Facies Associations n. 5 (Fig. 2).
F5 was divided in four main lithofacies with a variable areal distribution.
The lithofacies are:
F5A: massive wackestone with Ellipsactinia, Sphaeractinia, stromatoporoids, Tubiphytes sp. Stroma- tactis are common in some areas.
F5B: poorly stratified rudstone with stromatoporoids and some branching and single corals, Ellipsactinia is rare. The matrix consists of skeletal grainstone.
F5C: massive grainstone with fragments of stromato- poroids, Ellipsactinia, corals, gastropods (Nerinea sp.) and crinoid ossicles. Stromatactis are very abundant.
F5D: small lenses of skeletal grainstone (2-4 m wide and 30-40 cm thick), frequently laminated (low angle concave-convex lamination) and interbedded with F5A and F5C.
This facies association was interpreted as indicative of an external gently dipping margin (5-10°), below fair- weather wave base at a depth between 10 and 50 m (Bosellini & Morsilli, 1994). F5D is probably the result of storm wave action. F5C is related to wave action or small storms in the shallowest zone of this facies associ- ation (Morsilli & Bosellini, 1997).
Architectural and microstructural organization of the genus Ellipsactinia
In spite of the name, which indicates an elliptical shape, this morphology is quite rare. More usually, on the contrary, they have cylindrical, subconical, more or less slender shapes, which sometimes show incipient bi- or trifurcation. In some cases the shape is more irregular.
The sizes of the body ranges from few centimetres to more than 15 centimeters high. Very often the body may envelope small clasts, upon which the colony grows up asymmetrically mainly following a preferential direction (Fig. 3).
Fig. 3 - Field picture of Ellipsactinia showing the elongate shape of specimen, the “first lamella” (on the left of figure) and the differential erosion of lamellae (eroded and black) and interlaminar spaces (white and filled by calcite). Road from Foresta Umbra to Carpino. x 1.
Fig. 4 - The SEM microphotograph shows the “first lamella” pierced by pores, and the eroded lamellae showing the small sticks which cor- respond to radial channels, filled by calcite, crossing the lamellae. The interlamellar spaces are in relief because filled by calcitic cement.
Ellipsactinia specimen.
Fig. 5 - Thin section of Ellipsactinia specimen. Particular of “first lamella” with pores, and some following lamellae (larger and dark) separated by interlamellar spaces (narrow and white). x 7.
Architectural organization
The calcareous skeletal structure consists of superim- posed lamellae, more or less thick and spaced, linked by calcareous vertical pillars, similar to the stromatoporoid bauplan. These superimposed lamellae, deeply arcuated in the central part, converge towards the periphery, where they tend to blend. Sometimes the lamellae are deformed by small foreign bodies (Fig. 4).
In Ellipsactinia, generally, the lamellae are thicker than the interlamellar spaces.
In longitudinal section the lamellae show two kinds of pores (Fig. 5): larger, and smaller, with a diameter larg- er half part of previous ones, which represent the ending of radial channels. Also the first lamina or “parent lamel- la” (sensu Poljak, 1936) shows pores large about 100- 160 µm (Fig. 6), and others larger about 50-70 µm. The basal part of the coenosteum, which includes the first 5- 6 lamellae, shows the interlamellar spaces larger than those of the upper part of colony (Fig. 7).
The natural transversal cross section shows, on surface of half part of specimens, because of a differential ero- sion, the interlamellar spaces filled by a calcite fibro- lamellar cement, to be protrusive. The lamellae, on the contrary, in origin probably made up of aragonitic fibres, are eroded and appear as empty spaces (Figs. 3, 8). These spaces show calcitic interconnections (very similar to interlamellar pillars, as interpreted by previous authors such as Meneghini and Oppenheim), but they represent on the contrary the radial channels (Figs. 4, 8). These small channels cross perpendicularly the lamellae, and are generally filled by diagenetic calcite.
As pointed out by Canavari (1893), the original empty spaces (interlaminar empty spaces and channels) now are filled by diagenetic calcite and appear white, on the contrary the lamellae, probably constituted by fibrous- lamellar aragonite, now, because of the erosion, appear as empty spaces on surface. All the specimens studied in the present paper from the Gargano area show this type of differential erosion (Fig. 3). Canavari (1893) described, for specimens collected from Rocca Calascio, near Monte Camarda, southern part of Gran Sasso d’Italia, a reverse situation: i.e., the laminae are not erod- ed, and then are protruding, whereas the interlaminae
spaces are not filled, and then appear as empty spaces.
The true pillars (Fig. 9), in Ellipsactinia, generally connect two lamellae; sometimes they may be superim- posed on each other connecting several lamellae (Fig.
10). In this case they may simulate the tubuli. In the Ellipsactinia the pillars are fairly rare.
In longitudinal section, and/or in SEM observations, linear pseudotubuli (Fig. 11) crossing several lamellae are present. They appear, in thin section, as white struc- tures, 0.18 mm large and up to 3.5 mm long. They are produced by superposition on each other of some radial channels. Observed at the SEM, on the contrary, they appear filled by calcite, and they seem in relief.
Microstructure
As observed above, the skeleton of Ellipsactinia is entirely recrystallized in calcite. Neverthless it is possi-
Fig. 6 - Tangential thin section of “first lamella” and following lamel- lae to show the pore types in Ellipsactinia. x 6.
Fig. 7- Detail of “apical” part of Ellipsactinia showing “first lamella”, following lamellae and interlamellar spaces. On the left are visible few
“radial channels”. SEM photograph.
Fig. 8 - Detail of Ellipsactinia to show the radial channels (simulating
“false pillars”) of eroded lamella and interlamellar spaces filled by cal- cite (in relief).
ble to distinguish the original microstructure with an organization of fibers following a “water jet” (clinogo- nal) pattern (Fig. 13). These fibers start from a basal point and diverge going up to form a penicillate or
“water jet” arrangement. Generally each lamella consists of two superimposed layers of such fibers disposition.
Interbedded with the lamellae there are the interspaces filled by an ortho-fibrous calcitic cement (Fig. 12). Also
Fig. 12 - SEM microphotograph. Particular of an interlamellar space filled by ortho-fibrous cement. Ellipsactinia specimen.
Fig. 13 - SEM microphotograph. Particular of lamella microstructure showing the “water jet” (orthogonal) disposition of fibers. Ellipsacti- nia specimen.
Fig. 14 - SEM microphotograph. Particular of a monaxon spicule in Ellipsactinia.
Fig. 9 - Detail of thin section of Ellipsactinia showing the pillars. x 17.
Fig. 10 - Detail of thin section of Ellipsactinia showing the pillars laid one upon the other to form a “pseudotubulus”. x 12.
Fig. 11 - Detail of thin section of Ellipsactinia showing two “pseudo- tubuli”. x 13.
in this case this filling is made up of two superimposed layers separated by a thin discontinuity surface. There are present rare monaxon spicules, which lie on the tis- sue, without being immerged into the skeletal tissue, giv- ing the idea that they are fallen in (Fig. 14).
Architectural and microstructural organization of the genus Sphaeractinia
As in Ellipsactinia, the generic name, Sphaeractinia is related to the shape, but this is not always true. In fact the morphology varies from globular to elliptical, cylindri- cal, and sometimes shows incipient of bi- or trifurcation.
The size of colonies is variables, but generally they are smaller than Ellipsactinia. Very often the colony can envelope small clasts, upon which the colony grows up (Fig. 15).
Architectural organization
The superimposed lamellae, dark in colour, are thinner in the “marginal zone” (sensu Grubić 1983), and their tickness is about 0.18-0.20 mm, whereas the interlami- nar spaces may have the same tickness or be thicker, more than 0.30 mm.
The first lamella or “parent lamella” is pierced by numerous pores with diameters large about 0.30-0.50 µm (Fig. 16). The lamellae have a regular trend, some- times arched and convergent towards the astrorhizae-like organized radial tubuli. They show numerous large pores, and, sometimes, in tangential thin section it is possible to observe a meandriform skeletal tissue (Fig.
17).
As in Ellipsactinia, the lamellae, on surface, are erod- ed for some millimetres, and appear as empty spaces, whereas the interspaces are filled by calcitic cement and are in relief. On the longitudinal surface, these empty spaces, corresponding to original eroded lamellae, show interconnections representing the radial channels (Fig.
18). These small channels cross perpendicularly the
Fig. 15 - Field photograph of Sphaeractinia, in which are clearly visible the lamellae course, the radial channels and, on lower middle part of pic- ture, the “radial tubuli” arranged like astrorhizae pattern. Road from Foresta Umbra to Carpino.
Fig. 16 - Thin section of Sphaeractinia showing the “first lamella”
pierced by two type of pores (smaller and larger), the lamellae deeply perfored, and, on the upper left, the pillars laid one upon the other to form a “pseudotubulus”. x 7.
Fig. 17 - Tangential thin section of Sphaeractinia showing the meandriform tissue of lamellae and the pseudotubuli (lower part of picture). x 5.
lamellae, and generally are filled by diagenetic calcite.
The pillars (Fig. 19), on the contrary, connect two lamellae, and are much more numerous compared with Ellipsactinia. They are well ordered and superimposed
to each other like a “dry-stone wall”. Also in Sphae- ractinia pseudotubuli(Fig. 19) are present, but, unlike Ellipsactinia, there are also bundles of tubuli convergent towards the exterior, near the periphery, which have a special pattern simulating the astrorhizae of stromato- porids. The internal wall of these tubuli is lined by a dark film. These structures, typical only of Sphaeractinia, have been already observed by Canavari (1893), and are called radial tubuli (Figs. 20, 21).
Very rare and sparse monaxon spicules are present also in Sphaeractinia.
Microstructure
As in Ellipsactinia, also the skeleton of Sphaeractinia is entirely recrystallized to calcite. Neverthless it is pos- sible to distinguish the original microstructure with an organization of fibers following a “spherulitic” pattern (Figs. 22, 23). These fibers start from a central point and radiate all over the directions to form a spherulitic arrangement. Interbedded with the lamellae there are the interspaces filled by a “dog-tooth” calcitic cement (Fig.
24). There are present rare monaxon spicules, which lie on the tissue, without being immerged in the skeletal tis- sue, giving the idea that they are fallen in.
CONCLUSIONS
The classification of fossil sponges is based on the mineralogical composition and shape of the spicular skeleton, and therefore the lack of a spicular skeleton in most sponges makes their “natural” classification diffi- cult.
Even with these restrictions, it is possible to include Ellipsactinia and Sphaeractinia in the class Demo- spongiae, phylum Porifera, because of their microstruc- ture and skeletal organization. The systematic position at
Fig. 21 - Thin section of Sphaeractinia. Particular of radial tubuli (like astrorhizae pattern). x 17.
Fig. 20 -Thin section in Sphaeractinia. In the lower part of picture is clearly visible the radial tubuli arranged like astrorhizae. x 7.
Fig. 18 - SEM microphotograph. Detail of two interlamellar spaces (white and in relief) with an intercalated lamella showing the sticks of radial channels pointed out by differential erosion in Sphaeractinia.
Fig. 19 - Longitudinal thin section in Sphaeractinia showing numer- ous deeply perforated lamellae, pillars and pseudotubuli. x 7.5.
lower level, on the contrary, must be better defined.
There are, in fact, differences in the microstructure between these two genera. Ellipsactinia has a “water jet”
(clinogonal) fiber arrangement, whereas Sphaeractinia shows a spherulitic microstructure.
The genus Ellipsactinia Steinmann includes forms with peculiar features: laminae larger than the interlam- inar spaces, few pillars with an irregular arrangement
and finally, tubuli (pseudotubuli), very long but not in astrorhizae arrangement.
The genus Sphaeractinia Steinmann, instead, is char- acterized by laminae usually narrower than the interlam- inar spaces, “dry-stone wall” pattern of the laminae, which may exhibit meandriform structures, large num- ber of pillars also placed upon, numerous pseudotubuli and, near the periphery, radial tubuli with astrorhizae arrangement. Radial canals and spiculae are common features in both genera.
According to our preliminary research, it seems that Sphaeractinia is more abundant than Ellipsactinia in the Gargano. Further research is necessary to establish whether these two genera inhabited the same environ- ment.
Our interpretations are preliminary and should stimu- late further studies.
ACKNOWLEDGEMENTS - We thank Dr. Paolo Serventi and Claudio Gentilini for technical support. A particular thank to Prof. J. Pignatti, Università “La Sapienza”, Roma, for English improvement and useful suggestions.
Contribution to MIUR PRIN project 2004045107 (Palaeo- climatic forcing on building organism communities, carbonate productivity and depositional systems of some Italian Meso- Cenozoic shelf deposits). Bosellini A., coordinator.
Fig. 22 - SEM microphotograph. Sphaerulitic microstructure of Sphaeractinia lamella.
Fig. 23 - SEM microphotograph. Sphaerulitic organization of fibers making a sphaerulitic pattern.
Fig. 24 - SEM microphotograph. In the central part of picture the lamella tissue sandwiched by “dog-tooth” calcitic cement in a Sphaeractinia specimen.
REFERENCES
Babayev R.G. (1973) - Discovery of a rare Tithonian hydroid polyp in the USSR. Paleontological Journal, 7 (2), 237- 239.
Bachmayer F. & Flügel A. (1961) - Die Hydrozoen aus dem Oberjura von Ernstbrunn (Niederösterreich) und Stramberg ( ˇCSR). Palaeontographica, A, 116, 122-141.
Barattolo F. & Pugliese A. (1987) - Il Mesozoico dell'Isola di Capri. Quaderni Accademia Pontaniana, 8, 1-37, Napoli.
Bernoulli D. (1972) - North Atlantic and Mediterranean Mesozoic facies, a comparision. Initial reports of the Deep
Sea Drilling Project (Hollister C.D., Ewing J.I. et al. eds.), 11, 801-807, U.S. Government Printing Office, Washington D.C.
Bertotti G., Casolari E. & Picotti V. (1999) - The Gargano Promontory: a Neogene contractional belt within the Adriatic plate. Terra Nova, 11, 168-173.
Bosellini A. & Morsilli M. (1994) - Il Lago di Varano (Gar- gano, Puglia settentrionale): una nicchia di distacco da frana sottomarina cretacea. Annali Università di Ferrara (N.S.), Sez. Scienze della Terra, 5(1), 39-52.
Bosellini A. & Morsilli M. (1997) - A Lower Cretaceous drowning unconformity on the eastern flank of the Apulia Platform (Gargano Promontory, Southern Italy).
Cretaceous Research, 18, 51-61.
Bosellini A., Morsilli M. & Neri C. (1999) - Long-term event stratigraphy of the Apulia Platform margin (Upper Jurassic to Eocene, Gargano, southern Italy). Journ. Sedimentary Res., 69 (6), 1241-1252.
Bracco Gartner G., Morsilli M., Schlager W. & Bosellini A.
(2002) - Toe-of-slope of a Cretaceous carbonate platform in outcrop, seismic model and offshore seismic data (Apulia, Italy). International Journal of Earth Science, 91, 315-330.
Brankman C.M. & Aydin A. (2004) - Uplift and contractional deformation along a segmented strikeslip fault system: the Gargano Promontory, southern Italy. Journal of Structural Geology, 26, 807-824.
Canavari M. (1890) - Notizie paleontologiche. Atti Soc. Tosc.
Sc. Nat., Proc. Verb., 7, 250.
Canavari M. (1893) - Idrozoi titoniani della regione medi- terranea appartenenti alla famiglia delle Ellipsactinidi.
Memorie del Regio Comitato Geologico d’Italia, 4 (2), 155-209.
Capeder G. (1898) - Sulla probabile presenza delle Ellipsacti- nie nei calcari a Litotamni terziari. Torino.
Colacicchi R. (1967) - Geologia della Marsica orientale. Geol.
Rom., 6, 189-316.
Colacicchi R. & Praturlon A. (1965a) - Stratigraphical and paleogeographical investigations on the Mesozoic shelf- edge facies in Eastern Marsica (Central Apennines, Italy).
Geol. Rom., 4, 89-118, Roma.
Colacicchi R. & Praturlon A. (1965b) - Il problema delle facies nel Giurese della Marsica Nord-orientale. Boll. Soc. Geol.
It., 84 (1), 55-66, Roma.
Conti M.A., Morsilli M., Nicosia U., Sacchi E., Savino V., Wagensommer A., Di Maggio L. & Gianolla P. (2005) - Jurassic dinosaur footprints from Southern Italy:
Footprints as indicators of constraints in paleogeographic interpretation. Palaios, 20, 534-550.
Cremonini G., Elmi C. & Selli R. (1971) - Note illustrative della carta geologica d'Italia alla scala 1:100.000, Foglio 156 "S. Marco in Lamis". Servizio Geologico d'Italia, 66 pp., Roma.
D’Alessandro A., Laviano A., Ricchetti G. & Sardella A.
(1979) - Il Neogene del Monte Gargano. Boll. Soc. Paleont.
It., 18 (1), 9-116.
D'Argenio B. (1976) - Le piattaforme periadriatiche: una rassegna di problemi nel quadro geodinamico mesozoico dell'area mediterranea. Mem. Soc. Geol. It., 13 (1974), 137- 159.
De Dominicis A. & Mazzoldi G. (1989) - Interpretazione geologico-strutturale del margine orientale della piatta- forma Apula. Mem. Soc. Geol. It., 38 [1987], 163-176.
Funicello R., Montone P., Salvini F. & Tozzi M. (1992) - Caratteri strutturali del Promontorio del Gargano. Mem.
Soc. Geol. It., 41 [1988], 1235-1243.
Grubić A. (1959) - Eine neue Sphaeractinie. Bulletin du Muséum d’Histoire Naturelle, Art. Glasnik, A, 11. Beograd.
Grubić A. (1961) - Nov osvrt na proleme stratigrafije
Sferaktinida. Zavod za Geoloˇska i Geofiziˇcka Istraˇzivanja, Vesnik A, 19. Beograd.
Grubić A. (1983a) - Sphaeractinia poljaki Grubić from Prokletije. Vesnik A, 41. Beograd.
Grubić A. (1983b) - Result of paleontological and biostratigraphic study of Sphaeractiniids from Serbia and Montenegro. Mémoires du Service Géologique et Géophysique, 21, 1-51. Beograd.
Hoernes M. (1884) - Elemente der Paläontologie. Leipzig.
Hooper J.N.A. & Van Soest R.W.M. (Eds.) (2002) - Systema Porifera. A Guide to the Classification of Sponges. Vol. 1 and 2, Kluwer Academic/Plenum Publishers, New York.
Kühn O. (1927) - Zur Systematik und Nomenklatur der Stromatoporen. Neues Jahrb. Mineralogie, Paläontologie, Geologie, Abt. B, Centralbl., pp. 546-551.
Kühn O. (1939) - Hydrozoa. In: Schindewolf O.H., Handbuch der Paläozoologie, 2A, 1-68.
Lecompte M. (1951-52) - Les Stromatoporöides du Dévonien Moyen et Supérieur du Bassin de Dinant. Inst. Roy. Sci.
Nat. Belg., Pt. 1 (1951), Mém. 116, 1-125; Pt. 2 (1952), Mém. 117, 216-359.
Lecompte M. (1952) - Revision des Stromatoporöides mésozoïques des collections Dehorne et Steiner. Inst. Roy.
Sci. Nat. Belg., Bull., 28 (53), 1-39.
Leinfelder R.R., Schlagintweit F., Werner W., Ebli O., Nose M., Schmid D.U. & Hughes G.W. (2005) -Significance of stromatoporoids in Jurassic reefs and carbonate platforms - concepts and implications. Facies, 51, 299-337.
Martinis B. (1965) - Osservazioni sulla tettonica del Gargano Meridionale. Boll. Serv. Geol. It., 85, 45-93.
Martinis B. & Pavan G. (1967) - Note illustrative della Carta Geologica d’Italia alla scala 1:100 000, Foglio 157, Monte Sant’Angelo. Servizio Geologico d’Italia, Roma, 56 pp.
Mattavelli L. & Pavan G. (1965) - Studio petrografico delle facies carbonatiche del Gargano. Rend. Soc. Miner. It., 21, 207-246.
Moore C. (1956, ed.) - Treatise on Invertebrate Paleontology.
Coelenterata, Part F. Geological Society of America and University of Kansas Press., pp. 120-126.
Morsilli M. & Bosellini A. (1997) - Carbonate facies zonation of the Upper Jurassic-Lower Cretaceous Apulia platform margins (Gargano Promontory, Southern Italy). Riv. It.
Paleont. Strat., 103 (2), 193-206.
Nicholson H.A. (1886) - A Monograph of British Stromatoporoids. Palaeontographical Society, London.
Oppenheim P. (1889) - Beiträge zur Geologie der Insel Capri und der Halbinsel Sorrent. Zeitschrift der deutschen geologischen Gesellschaft, 41 (3), 442-490.
Oppenheim P. (1891) - Ueber das Alter des Ellipsactinien- Kalkes in alpinen Europa. Zeitschrift der deutschen geologischen Gesellschaft, 42, 778.
Ortolani F. & Pagliuca S. (1989) - Tettonica transpressiva nel Gargano e rapporti con le catene appenninica e dinarica.
Mem. Soc. Geol. It., 38 [1987], 205-220.
Ortolani F. & Pagliuca S. (1992) - Il Gargano (Italia meridionale): un settore di “avanpaese” deformato tra le catene appenninica e dinarica. Mem. Soc. Geol. It., 41 [1988], 1245-1252.
Osimo G. (1910) - Alcune nuove stromatopore giuresi e
cretacee della Sardegna e dell’Appennino. Mem. d. R. Acc.
delle Sc. di Torino, Serie II, 61 [1909-1910], 277-292.
PetkovićK. (1950) - Titon-Valanˇzinijen u Istoˇcnoj Srbiji. II O Znaˇcaju Nalaska Ellipsactinida u Sprudnim Kreˇcnjacima Suve Planine i Njima Sliˇcnim Ekvivalentnim Tvorevinama. Geoloˇski Anali Balk. Polnostrva, 17, 17-39.
Beograd.
Pfender J. (1937) - Quelques Hydrozoaires de la Syrie septentrionale. Notes et Mém. Haut-Comm. Républ. franç.
Syrie-Liban, Serv. Trav. publ., Sect. Etudes géol., 2, 1-125.
Poljak J. (1936) - Prilog poznavanju titonskih Hidrozoa Velike Kapele iz familije Ellipsactinida. Glasnik Hrvatskog prir.
Drustva, 41-48, 255-271.
Portis A. (1881) - Sui terreni stratificati di Argentera, Valle della Stura di Cuneo. Memoria paleontologico-geologica.
Mem. d. R. Acc. delle Sc. di Torino, Serie II, 34, 25-99.
Reitner J.(1992) - Coralline Spongien. Der Versuch einer phylogenetisch-taxonomischen Analyse. Berliner Geowiss. Abh., (E) 1, 1-356.
Remeš M. (1905) - Fauna der sog. exotischen Blöcke des Stramberger Kalksteine in Ryschalitz (Mähren). Bull. Inter.
Acad. Sci. Boheme, 10, 1-5.
Rigby J.K. (Coordinating Author, 2003) - Porifera. Revised.
Vols. 2 and 3., Treatise on Invertebrate Paleontology, Part E. The Geological Society of America, Inc. and The
University of Kansas, Boulder, Colorado and Lawrence, Kansas.
Stearn C.W. (1972) - The relationship of stromatoporoid to sclerosponges. Lethaia, 5, 369-388.
Stearn C.W. (1975) - The stromatoporoid animal. Lethaia, 89- 100.
Steiner A. (1932) - Contribution à l’étude des Stromatopores Secondaires. Bull. Lab. Géol. Univ. Lausanne, 50, 1-117.
Steinmann G. (1878) - Fossile Hydrozoen aus der Familie der Coryniden. Palaeontographica, 25, 101-124.
Steinmann G. (1888) - Ueber das Alter des Appenninkalkes von Capri. Berichte der Naturforsch. Gesellsch. zu Freiburg i. B., 4 (3), 48-52.
Turnšek D. (1997) - Mesozoic Corals of Slovenia. ZRC SAZU, 513 pp. Ljubljana.
Wood R. (1987) - Biology and revised systematics of some Late Mesozoic stromatoporoids. The Palaeontological Association. Special Papers in Palaeontology, 37, 1-89.
Zittel K.A. (1879) - Handbuch der Paläontologie. Bd. I, Paläozoologie, p. 286, München u. Leipzig.
Accettato per la stampa: Ottobre 2007
