A conventional view of trilobite autecology has envisaged these animals as particle feeding benthos, and does little to explain their morphological diversity within-habitat, nor the phylogenetic trends exhibited by particular clades. Phylogenetic analysis has led to new ideas about the relationships of major clades, and to concomitant advances in the way we understand the trilobite's adaptive deployment. In this new treatment the ventral surface is regarded as particularly important - and especially the relationship of the hypostome to the doublure, and its structure. The primitive mode of feeding is regarded as predatory/scavenging. This mode is retained by many trilobites having an attached and buttressed hypostome. It can be shown that modifications of the posterior margin of the hypostome - forks, 'mills' and the like - can be understood as adaptations for the manipulation of food. These trilobites made Rusophycus trace fossils. Particle feeding is regarded as an advanced character permitted by the detachment of the hypostome from the doublure in natant mode. The free floating hypostome may have assisted in the passage of particulate food forwards.into the digestive system. The result is a 'conservative ' morphology among trilobites of small size. The associated trace fossil are Cruziana of semiplicata type. A third feeding mode with vaulted cephalic shields is regarded as adapted to a form of feeding from suspension - this may go some way to explaining the aspect of the trinucleid fringe. "Bean" -like Rusophycus are associated. On the other hand, some bubble-like cephalic modifications which may have previously been associated with feeding are now better explained as adaptations for cephalic brooding. Trilobite communities comprised varying proportions of these different ecological types, and may have been optimised to avoid direct competition between species.
Structures without obvious counterparts or homologues among extant taxa tend to attract the attention of palaeontologists precisely because they are enigmatic. However, functional analysis of enigmatic structures can be problematic; studies of conodonts provide particularly good illustrations of some of the difficulties. The century and a half since the first speculation regarding conodont element function has seen the publication of diverse interpretations, hypotheses and opinions. These have drawn on a variety of analytical techniques with variable success, but most have been flawed by their reliance on a simple comparative methodology. The commonest approach has been based on analogy with extant organisms, and as knowledge of element structure, growth, skeletal architecture and biology of conodonts have improved, so have the constraints on these hypotheses. Nevertheless, even with the discovery of soft-tissue remains, no consensus view of element function emerged - a lack of agreement due primarily to difficulties inherent in the inference of function using analogy. Many such analyses are undermined by assumptions of functional optimality, but the real problem lies in the fact that analogy represent a useful tool in generating functional hypotheses but provides no means of rigorous testing. However, tests based on biophysical constraints can falsify functional hypotheses, and in the case of conodonts, predictions of allometry have been derived from the scaling relationships between surface areas, metabolic rate, and food requirements. Measured rates of element growth provide strong evidence that the conodont feeding apparatus did not form a suspension feeding array.
These tests still rely on a number of assumptions, the primary difficulty of this and almost all functional analysis of fossils being that functional data (i.e., direct observation and measurement of a structure in use) are unobtainable. But damage produced in life as a normal consequence of use can be preserved, and for fossils this represents the closest possible approximation of functional data. Using this approach, evidence of surface wear, microwear and recurrent patterns of damage indicates that conodont elements functioned as slicing, crushing and grasping teeth, some exhibiting precise interpenetrative occlusion.
The functional morphology of at least some groups of conodonts is now understood in detail, and this has broad implications for the way in which the conodont fossil record is interpreted. For example, the assumption implicit in many analyses of conodont palaeoecology, that the number of elements is proportional to the number of animals has been tested using evidence derived from functional analysis. Extending these results further, the evidence that conodonts were macrophagous supports scenarios that link the origin of vertebrates to an ecological shift from passive suspension feeding to active predation.
Glyptocystitids have a barrel-like or cylinder-shaped theca with a crown of sort arms in top and opposite it a flageliform stem. Externally, the theca has respiratory structures as discrete sets of rhomb-shaped folders groups, which are absent in Macrocystella, the most primitive known Glyptocystitid. Macrocystella has very thin and fragile plates, the surface is fold up with a triangular lattice pattern of hollow main and accessory ridges with thin walls. Each ridges continue in the adjacent plate making stronger plate joining, as result of it an overall rigid theca with very thin plates. Consequently, in Macrocystella respiratory surface and mechanical robustness are balanced by means of external ridges. Homocystites has tick plates with solid crests (homologous to primary ridges of Macrocystella) and internally has pectinirhombs which has thin folder walls.
The origin of pectinirhombs is here proposed as a modification of the secondary thecal ridges. This changes involve the increase of plates thick and the appearance of a "new thecal surface" from the external edge of accessory thecal ridges of Macrocystella. Similarly, the "old thecal surface" corresponds to the bottom of the folder-like structure of pectinirhombs. In these evolutionary changes, respiratory surface and mechanical robustness are balanced by means of thecal ridges. The discrete distribution of pectinirhombs is possible thanks to an increased affectivity of gaseous interchange throughout the walls of them.
A model of Homocystites was used in an eolic experiment. Whatever initial position, the theca turns around its axis and the periproct is orientated downstream. In that position, vorticity appears downstream of the theca when theca breaks the symmetry of the laminar flow regime as a Von Karman vortex trail. Furthermore, we will suggest a potential function of the thecal ridges to break the symmetry of the laminar flow regime, generating vorticity around theca creating upward funnels which could resuspend low-density particles from the bottom. This could justify the small size of the crown of this rhombiferans when they are compared with the crown of crinoids.
Recent bivalves appear to have a far greater diversity, in both taxonomic and ecological terms, than they have ever had before and the class has an excellent fossil record, arguably the best of any invertebrate group. These two facts should combine to make them one of the most promising candidates for truly palaeobiological work.
It widely believed that the primitive members of the class had relatively simple, bi-layered shells composed wholly of aragonite. Recent bivalves, however, show complex arrangements of different microstructures and employ both aragonite and calcite mineralogies. It is curious that the primitive arrangement (retained by some taxa) is mechanically superior to many of those which are derived. It is clear that the selection pressures which have driven this evolution must have been for factors other than strength alone. It has been suggested, based on knowledge of inorganic salts, that calcitic microstructures have lower solubilities that those of aragonite and that they have evolved as adaptations against shell dissolution.
Simple experiments have been used to test the relative solubilities of different shell microstructures. The results show that calcitic microstructures are not necessarily more resistant and indeed that solubility is determined by factors other than polymorph type. These finding have implications for our understanding of pre-mortem and post-mortem loss of shell material.
Planktonic graptolites responded with evolutionary innovation to the hydrodynamic demands of the water column. These demands, and the solutions which graptolites used to overcome them, can be determined experimentally. Models of graptolites are assessed in wind tunnels, using parity of Reynolds numbers to retain the utility of the analogue and laser Doppler anemomentry to measure flow in a non-invasive way.
Graptolite proximal ends were constructed in such a way as to determine a specific orientation for early growth stages, and this orientation changed twice or three times during early ontogeny. Spines and processes in this region were costly, in terms of the energy required to build them, but had a definite function which must have been vital to the survival of the colony.
Later colony orientation was controlled by the overall shape of the rhabdosome. Later spines and processes developed on thecae were used to generate effective feeding patterns around the thecal apertures. The shape of the apertures themselves controlled flow over the rhabdosome.
It is very important to determine those elements of graptolite form which were functional, in order to discriminate these from features which appear to be useless but conserved through evolutionary time, and which can give insight into the phylogeny of the group.
Planktonic foraminifera are undoubtedly one of the most studied groups of fossils. Their microscopic shells, found in great abundance in deep-sea sediments, have been used to reconstruct past climatic changes, to assess patterns of morphological evolution, and not the least, to establish high-resolution correlations of Late Cretaceous and Cenozoic sedimentary sequences. Yet, despite the intensity with which this group is investigated, little is known about the relationship between the form and the function of their shells. Many attempts have been made to explain the recurrent development of certain modifications of the shell during geological time, often suggesting a close link between individual morphologies and specific environmental parameters. Recent studies have shown, however, that none of these explanations is universally valid.
Planktonic foraminifera provide a unique tool for assessment of rates and patterns of morphological evolution. It is in this group of fossils where the best documented examples of evolutionary transitions between species have been described. Yet, although the fossil record of planktonic foraminifera allows direct tracing of ancestry, quantification of rates of morphological change and tracking of spatial patterns of speciation, the insufficient knowledge of the function of their shells has been gravely limiting the interpretation of such data. Recent advances in DNA extraction from modern planktonic foraminifera, as well as stable isotopic studies of habitat changes of their fossil relatives have cast additional doubts on the biological meaning of the well documented evolutionary patterns in this group. If there are cryptic species of planktonic foraminifera, if changes in the shape of their shells during the evolution occur out of phase with changes in their ecological preferences, does it mean that shell form is in fact not subjected to the machinery of natural selection?
Here, I present data on morphological evolution in a late Neogene planktonic foraminifer lineage. A detailed investigation of the changes in the relative abundance and size of secondary openings in the shells of this lineage suggests that there was a strong selection against this character. Thus, it seems that at least in some cases morphological evolution of planktonic foraminifera may indeed reflect the biological processes of natural selection. This implies that recent findings on the functional morphology of planktonic foraminiferal shells do not imply a threat to studies of morphological evolution in this group; rather they provide a challenge and a great prospect for future investigations.
Radiolarians are unicellular marine plankton belonging to the rhizopoda, a group of organisms that use long thin threadlike external extensions of the protoplasm in feeding and movement. Radiolarians are micro-heterotrophs, feeding on smaller plankton, although some species also harbor photosynthetic symbionts. Radiolarians secrete shells of opaline silica that are extremely well preserved in the fossil record, allowing study of their evolution. The shell is partly deposited within the highly structured cytoplasm of the cell, and partly in the external envelope of vesicles and feeding rhizopods. The deposition of the shell is under tight developmental control and is apparently species specific, and the shell form of species is quite stable on evolutionary time scales. Radiolarian shells are found in a bewildering variety of forms, including cones, spheres, discs, spirals, rings, valves, and thousands of variations on these themes. If the geometric distinctiveness of the bauplan were the only criterion, radiolarians would be classified into many different phyla. Yet radiolarians share a similar ecologic niche to other planktonic organisms, such as planktonic foraminifera, that are vastly less diverse in their skeletal and cytoplasmic architecture.
If the morphology of organisms is primarily functional, why should this dramatic difference exist? For what functional purposes do radiolarians possess this great diversity of form?
Crown-group Asteroidea and Ophiuroidea (asterozoans, Echinodermata) are highly distinct both in terms of functional morphology and mode of life. For example, extant asteroids move utilising tube feet, whereas ophiuroids locomote by virtue of highly flexible muscular arms; most asteroids are active predators of small benthos, whereas the majority of ophiuroids are detritivores. However, the earliest representatives of each class differ far less markedly. Asterozoans first appeared during the Upper Tremadoc (Lower Ordovician) and initially included a number of bizarre or 'intermediate' taxa that have proved hard to classify. Yet by the Caradoc, less than 40 million years later, asteroids and ophiuroids had developed many of their crown -group structural features and were functionally distinct. Placement of such intermediate forms is crucial in understanding the pathways followed during the origin and subsequent diversification of asterozoans.
To set this morphological and functional divergence in an evolutionary context, type material for every Ordovician genus of asteroid, ophiuroid and somasteroid has been restudied and homologies of plate systems between genera established. This in turn has been used to generate a cladistic hypothesis for early asterozoan origins and relationships. Placement of taxa within a robust phylogenetic scheme allows the order in which the key crown-group distinctions appeared to be determined and provides a framework for interpreting the asterozoan radiation in a functional and ecological sense. Calibration of phylogenetic data with the stratigraphic occurrences of taxa allows an evaluation of the rapidity in which species numbers (biodiversity) and morphological distinctiveness (disparity) were obtained in these animals, and a comparison to contemporaneous diversifications in the Lower Palaeozoic biota.
Although for the purposes of systematics it is convenient to treat organisms as sets of uncorrelated characters, it is clear that at least some aspects of morphology in a particular organism form tightly integrated units. The extent to which the morphology of an organism is integrated effectively determines how valid the idea of a 'body plan' is for that individual. Structural and functional integration may be investigated by drawing up networks of relationships between different morphological components, a technique championed by Dullemeijer for vertebrates, but rarely applied to invertebrates. This surprisingly tricky task emphasises both how complex apparently simple systems are, and also which components of the system are the most and least constrained. However, identification of the degree of constraint within the system allows the following interesting questions to be addressed: first, does the system constraint have an effect on the morphologies adopted in an adaptive radiation? secondly, in cases where system constraint is overcome, how can this occur?
Arthropods - including stem-group forms - represent an excellent case study for the application of these techniques because of their complex morphology that is often well-preserved in the fossil record. Cambrian arthropods are particularly well-represented because of their abundance in the various Cambrian lagerstätten. Phylogenetic analysis of early arthropods allows distinct ecological and functional scenarios to be postulated for the ancestors of various major groups, and thus the ecology of the radiation may be analysed. In particular, it can be seen that the assembly of the euarthropod body plan was accompanied by considerable ecological and morphological diversifications which indeed appear to have been constrained by functional and structural considerations. Functional analysis suggests that these constraints, such as those acting on dorsal sclerites, limb movement and in particular the overall muscle system, and which had to be overcome before the euarthropod body plan could evolve - would have only been avoidable in animals of large size. Morphological and functional analysis thus allows the strong hypothesis to be put forward that not only did the ancestral euarthropod happen to be of a large size, but that it had to have been.
Heteromorph ammonites have been envisaged as exploiting a wide variety of different lifestyles, from planktonic filter feeders to active demersal predators. A useful tool for interpreting ecology is the orientation of the ammonite during life. This depends upon estimating the centres of mass and buoyancy, which is related to the size and shape of the soft body parts and their association with the shell.
The classic study of this by Trueman (1941) assumes that the ammonite completely occupied the living chamber of the shell. More recent studies have challenged this assumption, postulating that the soft body parts may have been much larger (Ebel, 1992) or smaller (Monks & Young, 1998) than previously thought. Differences in body size have profound implications in the orientation of the shell and consequently the ability of the ammonite to swim or crawl about on the sea floor.
Cladistic analyses of the Albian radiation of the heteromorph ammonites and the occurences of certain morphologies in sediments of particular environments give some clues to the evolution of the group. Certain forms, which the model devised by Monks and Young (1998) suggests are likely to be planktonic (Monks, in press), are restricted to deeper water facies. They may be ecological analogues to the modern deep water cranchid squids.
Ebel K, Lethaia, 25, 179-193, (1992).
MonksN, Bolletino Malacologico, in press, (1999).
Monks N & Young JR, Palaeontologica Electronica, 1, (1998).
Trueman AE, Quarterly Journal of the Geological Society of London, 384, 339-383, (1941).
The Rugosa show some very conspicious examples of solitary corals. These corals do not have a round shape but are unilaterally flattened (a slipper like shape, Calceola) or they have a rectangular shape (Goniophyllum). Furthermore these corals have a lid by which the can close their polypars. The internal structure of the soft bodies of these corals and some of their structural functional aspects can be reconstructed on the basis of biological and morphological knowledge on the recent corals, in order to give testable models for internal structure and evolutionary pathways from the rugose bauplan to the bauplan of Calceola and Goniophyllum. The soft body of a rugose coral consists of a gastrovascular cavity that is filled by water, an actinopharynx that closed in a valve like manner, internal single mesenteries that act as tethers between the oral disc, pedal disc, and body wall, and tentacles that are formed on the oral disc at the sites of the mesenteries. During their individual development, new mesenteries are added only in four insertion zones and as a consequence automatically septa are added only in the spaces between the mesenteries. This arrangement causes structural-functional limitations for the evolution of the rugose corals and for their abilities to form colonies or reefs. But in some cases structural-functional limitations open new evolutionary pathways. The examples of the lid corals represents such new pathways in evolutionary transformation of a rugose coral. Calceola as well as Goniophyllum evolve by quite simple modifications of the general bauplan of a rugose coral. Their peculiar shapes, the lids and especially the even hinges between the calyx and the lid(s) are caused only by mechanical necesseties. Under special conditions (such as high sedimentation rates) these bauplans represent suitable survival strategies.
Numerous important groups of plankton protists have mineralized skeletal (sensu lato) structures - notably diatoms, radiolarians, planktonic foraminifera, silicoflagellates, and coccolithophores. The relative success of such groups strongly indicates that the skeletal structures they produce have adaptive value, but understanding the functions they perform and their functional morphology is problematic. Common problems include, the intrinsically passive role of these structures and the difficulty of making useful observations on live organisms. Coccolithophores present an extreme case, since: coccoliths are entirely extracellular structures and in culture naked cells frequently occur and are apparently as viable as calcified cells. So these elaborate sructures cannot play any essential role in cell physiology, despite which they have continued to be produced through 200 Ma of evolutionary history. Perhaps in consequence, the function of coccoliths has been extensively analysed. From this a number of generalisations can be drawn. First, much of the apparent fine scale complexity and diversity is a function of biomineralization processes. Second, the most pervasive general trend is toward production of a robust, continuous, but permeable, extracellular cover. Various morphotypes apparently adapted toward this end recur homoeomorphically. For these protective functions are most likely. Third, in oligotrophic environments a wide range of morphotypes produce relatively delicate extended cell-coverings, for which the likely function is modification of cell-environment interactions. Fourth, various species show elaborate modifications of coccolith morphology which seem likely to be adaptations toward secondary functions probably including flotation modification, light concentration and carbon fixation (none of which are tenable as universal functions of coccoliths).
Perhaps the most valuable contributions of functional considerations have, however, been to focus thought on aspects of coccolithophorid biology and palaeobiology which are otherwise often conveniently ignored. In order to make reliable palaeobiological inferences we need to develop an holistic understanding of our organisms, and attempting to address the awkward questions posed by functional analysis can form a major contribution to this.
The Adriatic carbonate platform (ACP) (Triassic - Upper Eocene) was place where many organisms appeared, evolved, spread and disappeared according to their evolutionary trends, paleoecologic conditions (on local or regional scale) and tectonic synsedimentary events. Adaptation on paleoecologic conditions through changes in forms is well preserved in rudists and orthophragminids (studied on several sections exposed along the Eastern Adriatic Coast).
All rudists that appear on the ACP after the Early Turonian transgression were elevators (Skelton & Gili, 1991). Density of rudist congregations ranges from highly sparse to densely packed congregations (Gili et al., 1995), and their appearances were quite diverse. Within limestones originated on the carbonate platform is possible to recognise paleoecological zonation, from shallowest part of subtidal with densely packed Radiolites thicket, over mixed radiolitid-hippuritid assemblage, to rare Vaccinites-Hippurites assemblage of outer shelf. Complete mutual support of Radiolites individuals (slim, cylindrical shells) resulted in dense packing, which may have prevented possible colonisation of the other benthos. Difference in diversity of the congregations could be due to fact that small bodied radiolitids were probably more r-strategists. By contrast, some large-bodied taxa (as Vaccinites) probably were K-strategists (Gili et al., 1995). The monospecific nature of the Radiolites thickets could also reflect the rapid settlement of larvae on a temporarily available shallow subtidal substratum, perhaps followed by passive biochemical attraction of later conspecific recruits or competitive interference with other settlers (Skelton et al., 1995). By contrast, Vaccinites and Hippurites preferred slightly deeper subtidal environments that presumably have less tendency for hypersaline fluctuations.
Orthophragminae, informal name for Paleogene larger foraminifera (Drooger, 1993) includes two systematically independent families, Discocyclinidae and Orbitoclypeidae (Ferrandez-Canadell, 1998). In Paleogene transgressive sedimentary successions orthophragminids, among larger foraminifera, had appeared as the last (Ypresian) and did disappeared as the last (Bartonian).Studies of orthophragmina-bearing limestones reveal: 1) the first occurrence of orthophragminids characterised their great morphologic diversification (less abundance), with predominant thick, large assilinids, operculinids and nummulitids. Orthophragminid shells (average T/D ratio > 1) exhibit conspicuous ornaments in central part (if umbo is developed otherwise size of these structures slightly diminishing towards the test periphery) interpreted as far as lenses collecting light for symbionts (Ferrandez-Canadell & Serra-Kiel, 1995). Lateral chamberlets are spacious (average dimension 80 µm in diameter and 40 µm high) divided by lamellae 0.03-0.09 µm thick. 2) less diversified larger benthic paleocommunity composed of flat operculinids, small nummulitids and orthophragminids occur in the upper part of the succession, along with common occurrence of planktic foraminifera. Orthophragminids are extremely thin (T/D ration about 0.17), flattened lateral chamberlets (average dimensions about 120 µm in diameter and 30 µm high) are separated by lamellae 0.012-0.014 µm thick; piles regularly distributed all over the tests (their size differences are negligible).
Drooger WJ, Verh. Kon. Ned. Ale. Wet., afd. Natuurk., E. Reeks, 41, 241 pp, (1993).
Ferrandez-Canadell C, Journal of Foram. Research, 28/2, 135-140, (1998).
Ferrandez-Canadell C & Serra-Kiel J, Rev. Esp. Paleontol, No Homenaje G. Colom, 129-135, (1995).
Gili E, Masse J-P & Skelton PW, Palaeogeogr., Palaeoclimatol., Palaeoecol, 118 (3-4), 245-267, (1995).
Skelton PW & Gili E, First International Conference on Rudists, October 1988, Proceedings (ED. by M. Sladic-Trifunovic). Sebian Geological Society, Issued only as reprint from unpublished volume, 71-86, (1991, in press).
Skelton PW, Gili E, Vinces E & Obrador A, Palaeogeogr. , Palaeoclimatol. , Palaeoecol, 119, 107-126, (1995).
Previous work has shown that the size and shape variability of living organisms tend to be highly correlated. This observation was also identified within a number of planktonic foraminifera species. Many of these species show a correlation of size and shape variability with environmental conditions (e.g. Hecht 1976, Naidu & Malmgren 1995). Detailed studies of species size variation revealed geographic and downcore patterns of average test sizes. However, the correlation between size and environmental parameters is restricted to the optimal environmental conditions for the individual species.
The purpose of this study is to extend the use of the size-ecology relationship to a global scale. Assuming an assemblage is adapted to its environmental conditions, it is reasonable to test for a correlation between the average test size of the whole assemblage and its specific ecology. Therefore, the average size of undifferentiated foraminifera was measured using an automated system.
Various size parameters such as maximum diameter, width and area of planktic foraminiferal tests in 22 globally distributed surface sediment samples were measured. An average of 700 foraminifera larger than 150 µm were analyzed in each sample. The foraminifera were strewn on a picking try, digitized up to 6 at a time with a frame- grabber and shape parameters were recorded using Image Analyst/Mac Rail software. The correlation of the calculated mean diameters and areas with temperature, salinity (NOAA) and primary productivity (Antoine et al. 1996) was analyzed.
Size variability within each assemblage is small in polar areas and increases towards tropical regions. Mean diameters correlate with mean annual sea surface temperatures. Mean diameters are significantly smaller over the temperature range of 10°C to 18°C than in areas with colder surface waters. In warm subtropical surface waters the mean diameters increase to a maximum and decrease again in tropical waters. Assemblages from partially dissolved or winnowed samples depart from this general pattern.
Mean diameter of planktonic foraminiferal assemblages is positively correlated with annual primary productivity. The influence of temperature and primary productivity can not yet be resolved as these factors are correlated with each other in most of the samples analyzed so far. However, the scatter of the size versus temperature relationship in subtropical regions is reduced when samples from eutrophic and oligotrophic environments are considered separately. Future work will resolve more clearly the individual effects of temperature and food supply.
Hecht AD, J. Foram. Res., 6, 295-311, (1976).
Naidu PD & Malmgren BA, Paleoc, 10, 117-122, (1995).
World Ocean Atlas, NOAA server, (1994).
Antoine D, André JM & Morel, A, Global biogeochemical cycles, 10, 57-69, (1996).
The linkage between benthic Foraminifera morphology and environment are widely documented in literature. Starting from this sound substrate of data an analysis of the morphofunctional and morphoadaptive characteristics of the assemblages from eight stratigraphical sections has been led. These sections are located in Western Monferrato (NW Italy) and have been dated as Lower-Middle Miocene in age on the base of planktic Foraminifera. The analysis of benthic assemblages has allowed to distinguish 10 morphotypes, based on test shapes and coiling, partly modifying the morphological categories used in the recent literature. Six morphotypes typical of infaunal microhabitats, four morphotypes connected to epifaunal microhabitats and two characteristic of epiphitic microhabitats were recognized. Each microhabitat is characterized by particular palaeoenvironmental gradients such as physicochemical properties of the substrate, mainly depth, lithological nature of the bottom, dissolved oxygen concentration, organic matter content and food availability. In detail the study of the quantitative ratios between the more frequent morphotypes has allowed to distinguish three associations closely connected to the characters of the lithofacies and indicative of definite bathimetric zones, respectively related to inner platform, outer platform and upper slope environments. The effectiveness of the use of foraminiferal morphogroups in palaeoenvironmental reconstructions has been tested by means of the comparison with autoecological information derived from quantitative analysis of each benthonic taxa recognized. Such comparison demonstrates the clear connection existing among the frequency of the taxa, their morphofunctional and morphoadaptive characteristics and their microhabitat preferences. These results stress the importance that the study of foraminiferal morphotypes plays in the palaeoecological reconstructions: the method has proved to be considerably reliable and definitely more rapid and of easy performance in respect to a traditional synecological analysis of the assemblages. In this context it is more than ever evident the necessity to integrate palaeobiological data and litho-sedimentological data.
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