Contr. Tert. Quatern. Geol. 30(1-2) 29-39 1 fig., 5 tabs Leiden, June 1993 The distribution of Pliocene Nassariidae (Mollusca, Gastropoda) from the western Mediterranean: palaeoecological and historical considerations Carles Gili and Jordi Martinell Facultad de Geologia Universidad de Barcelona Barcelona, Spain Gili, Carles, & Jordi Martinell. The distribution of Pliocene Nassariidae (Mollusca, Gastropoda) from the western Mediterranean: palaeoecological and historical considerations. — Contr. Tert. Quatern. Geol., 30(1-2): 29-39, 1 fig., 5 tabs. Leiden, June 1993. The palaeobiogeographyand palaeoecology (and possible factors determining these) oftwenty-seven species ofnassariid gastropod which inhabited the Mediterranean and of the Atlantic Ocean the Pliocene Tables of for these parts during are analysed. presence-absence species and faunal affinity indexes are presented. The study ofthe causal factors ofthis distribution is based onecological aspects, mainly available and historical with the of conditions and relying on outcrop data, aspects regard to present knowledge general changes prevailing in the area during the Pliocene. Key words — Mollusca, Gastropoda, Nassariidae, Pliocene, Mediterranean,palaeobiogeography,palaeoecology. C. Gili and J. Martinell, Departamento de Geologia dinamica, Geofisica i Paleontologia, Facultad de Geologia, Universidad de Universitaria de Barcelona; zona Pedralbes, E-08071 Barcelona, Spain. Contents (1976, 1982b), Gili & Martinell (1990) and Gili (1991). A taxonomic revision, based on modern cri- Introduction 29 p. is in order deal with teria, a necessary step to more Material and methods p. 29 general palaeontological problems, especially when Distribution characteristics 31 p. working at the specific level. considerations 34 Ecological p. and The present study comprises a qualitative Historical considerations p. 36 quantitative analysis of presence-absence tables of Conclusions 37 p. the within the species study area (western Mediter- Acknowledgements p. 38 ranean) and relates the results obtained to data References p. 38 available on the ecological conditions expressed in the strata from which the species have been col- and the historical Introduction lected, on modifications having occurred in the the area during Pliocene. of this of The aim study is to present a description the distribution of geographical patterns twenty- MATERIAL AND METHODS seven species of nassariid gastropod which inhab- ited the Mediterranean and the Atlantic The material under consists of data parts of study locality Ocean the Pliocene. for of the Nassarius during The palaeobiogeo- twenty-seven species genus distribution is with the aid of 1806 lat. in in graphical interpreted Dumeril, s. (Table 1) outcrops the the causal both and factors, ecological historical, eastern and western Mediterranean and in some which underlie such distribution Atlantic close the Strait of patterns. localities to Gibraltar; As is made the have been in a starting point, reference to sys- they grouped the fourteen basins or tematic revision of the species studied by Martinell zones indicated in Fig. 1. 30 the location ofthe basins - Fig. 1. Map showing studied. Abbreviations are as follows: MA Atlantic Morocco; H - Huelva; MM - Mediterranean Morocco; A - Algeria; BE - Baix Ebre; BL - Baix Llobregat; AE - Alt - - - Empordà; R Roussillon; CR Rhône basin; AM Alpes Maritimes; CI - western Italian basin; S - Sicily; T - Tunisia; NI - northern Italy. the has and another Part of present study focused on outcrops species were located (Table 1), study of in northwestern Mediterranean indicated the In basins, as the strata in which species occur (Table 2). in Table 2. Data have been obtained from direct based these a addition, a quantitative analysis on of fossil with tables comparison our own collections speci- using faunal affinity matrices as calculated housed in various and universities the Dice index mens museums according to (Cheetham & Hazel, de carried (Museu de Geologia Barcelona; Institut Royal 1969) was out (Tables 3 and 4). Every table des Sciences naturelles de la Belgique, Brussels; was used for the analysis of different aspects of the Departement des Sciences de la Terre, Universite biogeographical study. Claude Bernard, Lyon; and Museum national By grouping the data available for all deposits of d'Histoire naturelle, Paris), making sure that any one basin distinguished (Table 1), it is possible locality data could be verified and taphonomic to determine whether problems result from 'non- characteristics were known. These data have been significant' absences or collection failure. This pro- the complemented with bibliographical data thought to cedure permits inclusion in the same register of be relevant with to the studied those which lived all of the regard species (Gili, species at or many in 1991). localities in one basin, but are found only one or few Literature data should be used with caution ifone localities. This table results from a direct study is level it is the material working at species as quite common to of and from a literature search. whether the the encounter uncertainty as to specific To ensure a maximum reliability of data, author that for need be name used by one corresponds to those the various zones to as homoge- applied to our material. Consequently, these data neous as possible. Therefore, we have fewer data for do the have been used only sparingly as they not allow a following basins: Moroccan Atlantic, Moroccan and more precise discrimination. Mediterranean, Algeria Tunisia, mainly The following course was taken: a qualitative because these are the basins that have been studied in the least analysis based on presence-absence tables was car- detail. This fact must be taken into ried out, in relation to the basins in which the account when interpreting the results and when 31 SPECIES H BEBE BL AE R CR AM CI S T A MM MA NI N. Bas. N.JV. pliomagnus (SACCO, 1904)1904) + + + +t + + + + + +++ + + + + 14 N.JV. companyoicompanyoi (FONTANNES,(FONTANNES, 1879) + + + +++ + + + ++ + 9 N. obliquatusobliqualus (BROCCHI,(BROCCHI, 1814) + 11 N.JV. clathratusclathratus (BRONN, 1788)1 788) + +f + + + ++++ ++++ + 10 + + 1 1 N.JV. prismaticus (BROCCHI,(BROCCHI, 1814) + ++ + + +++ + + + ++ + 11 N.JV. bisotensisbisotmsis (DEPONTAILLER,(DEPONTAILLER, 1879)1879) + 1 1 N.JV. ligusticus (BELLARDI, 1882)1882) + 1 N.JV. aff.aff. ligusticus (BELLARDI, 1882) + 1 14 N.JV. semistriatussemistriatus (BROCCHI, 1814) + ++ + + 4-++ + ++ + + +++ + + + + N.JV. elatuselatus (GOULD,(GOULD, 1845) ++ + + + +++ + ++++++ + + + 11 M. martinelli (GILI,(GUJ, 1992) ++ 11 N.JV. cabrierensiscabrierensis (FLSC.(FISC. & TOURN., 1873) + + + + + + + + 8 N.JV. macrodon (BRONN, 1831)1831) + +++ + + ++++ + + + 8 N.JV. reticulatus (LINNÉ,(LINNÉ, 1758) + + + + +++ + + + ++ + + 11 N.JV. corrugatus (BROCCHI, 1814) + 11 N.JV. bugellensis (BELLARDI, 1882) ++ + +3+ 3 + N.JV. angulatus (BROCCHI,(BROCCHI, 1814) + + + ++ + +++ + + + + + + 12 N.JV. asperulus (BROCCHI,(BROCCHI, 1814) + ++ + + + ++66 N.JV. serraticosta (BRONN, 1830) ++ ++ ++ + + ++ +++ + + + + 11 N.JV. catulloi (BELLARDI, 1882) + ++ + + ++55 N.JV. productusproduclus (BELLARDI, 1882)1882) + + + 3 N.JV. turbinellus (BROCCHI, 1814)1814) + + + +4+ 4 N.JV. quadriserialis (BON.(BON. inin MICH., 1838) + +2+ 2 N.JV. bollenensis (TOURNOUER,(TOURNOUER, 1838) + + ++ + 4 N.JV. gibbosulusgibbosulus (LINNÉ, 1758)1758) + +++ + +++ + + +++8+ 8 N.JV.pyrenaiatspyrenaicus (FONTANNES, 1879) + + + ++ + ++66 N.JV. temtoturritus (BORSON, 1820) + ++ + +++ + +++ + +f + 99 N. Sp.-Basin 12 5 14 15 14 14 22 1212 1313 10 88 8 6 22 Table 1. Presence of species in the various basins. Abbreviations are as follows: N. Bas. - number of basins; N. Sp.-Basin - number of species in each basin. conclusions. The table of The use of the index a drawing presence per out- affinity permits quantifica- tion of the thatexist between faunas of crops (Table 2) permits to distinguish more concrete relationships of the distribution within each basin aspects or different basins (Table 3), or between different out- between different zones. Yet, not only must our crops within the same basin or between different all Data obtained allow diverse knowledge of the fauna then be comparable for zones (Table 4). to test but also of be distribution and deposits, a uniformity sampling must hypotheses as to patterns underly- ensured. Therefore, this table depends exclusively ing causes. on the material and deposits studied personally. of the Thus, only twenty-three twenty-seven species have been considered. Another essential factor, ta- DISTRIBUTION CHARACTERISTICS phonomy, must be considered when evaluating eco- those beds of the logical factors of distribution. Only for The overall distribution twenty-seven species which has demonstrated the in the is follows: a taphonomic study used present investigation as fossil fauna to correspond to a palaeocommunity or — twenty are found both in the eastern and western 'census assemblage' (Hallam, 1972; Kidwell & Bos- Mediterranean; useful. Others this cri- — fifteen found also in the Atlantic to ence, 1991) are not meeting are adjacent terion must be disregarded. Thus, the fauna from the Mediterranean; the Can — five restricted the Albareda outcrop (Baix Llobregat basin) are to western Mediterranean; has — restricted in northern not been considered as it represents an accu- two are to deposits Italy Adriatic Pliocene of the mulation level, its record corresponding to a (the eastern thanatocoenosis (Fiirsich, 1990). Mediterranean).