published online - NEW ADVANCES IN ITALIAN PALAEONTOLOGY - Volume 2 (R. Sanfi lippo & A. Rosso Editors) atania 24-26 Maggio 2012 Bollettino della Società Paleontologica Italiana, 2013, i-x. Modena Faunas and ecological groups of Serpuloidea, Bryozoa and Brachiopoda from submarine caves in Sicily (Mediterranean Sea) Antonietta ROSSO, Rossana SANFILIPPO, Emma TADDEI RUGGIERO & Emanuela DI MARTINO A. Rosso, Università di Catania, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Sezione di Scienze della Terra, Corso Italia 57, I-95129 Catania, Italy; [email protected] R. Sanfi lippo, Università di Catania, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Sezione di Scienze della Terra, Corso Italia 57, I-95129 Catania, Italy; sanfi [email protected] E. Taddei Ruggiero, formerly at the Università di Napoli Federico II, Dipartimento di Scienze della Terra, Largo San Marcellino 10, I-80100 Napoli, Italy; [email protected] E. Di Martino, Università di Catania, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Sezione di Scienze della Terra, Corso Italia 57, I-95129 Catania, Italy; Department of Earth Sciences, Natural History Museum, Cromwell Road, SW7 5BD London, United Kingdom; [email protected] KEY WORDS - Serpuloideans, bryozoans, brachiopods, submarine caves, Sicily, Ionian Sea, Tyrrhenian Sea, Holocene. ABSTRACT - Serpuloideans, bryozoans and brachiopods, which are among the most representative sessile skeletonised invertebrates in marine caves, are examined herein from four selected submerged marine caves: the Ficarella Cave (NW Sicily, Tyrrhenian Sea), and the Gymnasium, Mazzere and Granchi Caves (SE Sicily, Ionian Sea). A large number of the identifi ed species are already known as typical representatives of cave communities or, at least, have been already found in submarine caves. In order to better understand the composition of these communities, a categorisation of cave species into ecological groups is proposed herein, based mainly on literature data: 1) Cave species; 2) Sciaphilic and/or “coralligenous” species; 3) Deep-water species; 4) Shelf species; 5) Shallow shelf species; 6) Unplaced species. The use of these different ecological groups is proposed as a tool for the analysis and interpretation of thanatocoenoses and fossil communities from caves. RIASSUNTO - [Faune a serpuloidei, briozoi e brachiopodi, e gruppi ecologici in grotte marine sommerse della Sicilia (Mar Mediterraneo)] - Sono stati studiati serpuloidei, briozoi e brachiopodi di quattro grotte sottomarine ubicate a circa 20 metri di profondità nella Sicilia NO (Grotta Ficarella) e SE (Grotte Gymnasium, Mazzere e Granchi). I gruppi sessili studiati sono tra i più rappresentativi negli ambienti di grotta e comprendono esemplari viventi e resti scheletrici campionati lungo le pareti e le volte, e nei sedimenti di fondo. Tutte le specie individuate (in totale 162) sono state inserite in sei raggruppamenti ecologici principalmente in base a dati di letteratura: 1) Specie di grotta; 2) Specie sciafi le e/o “coralligene”; 3) Specie di profondità; 4) Specie di piattaforma; 5) Specie di piattaforma superiore; 6) Specie senza preciso signifi cato. Le grotte di entrambe le aree sono colonizzate in prevalenza da specie del gruppo 2, spesso presenti con un elevato numero di esemplari, e subordinatamente da specie dei gruppi 1 e 3, che nell’insieme sono indicativi di associazioni di grotta. La differente incidenza delle specie superfi ciali fotofi le (gruppo 5) nelle varie grotte è indicativa di input esterni di differente entità provenienti da habitat antistanti le cavità, soggette a differenti gradi di esposizione. L’analisi dei differenti gruppi ecologici si propone come uno strumento investigativo utile nello studio delle tanatocenosi e delle associazioni fossili di grotta. INTRODUCTION in the Mediterranean area. The communities refl ect the geographical location, morphology and history of the Benthic ecosystems from shallow water submarine cave and the local pool of species, as well as the timing caves are unique in representing enclaves similar in and succession of larval infl ows, causing in turn, biotic composition to deeper environments but located only complexity and competition (Harmelin, 1980, 1985, a few metres below the sea level (Vacelet et al., 1994). 1997, 2000; Bianchi & Morri, 1994; Martì et al., 2004). Consequently, habitats and life within caves differ Hence, each cave has its peculiar species composition, markedly from those of neighbouring systems. Reduction even though caves of the same geographical area share a in light and water motion, and exchange with external certain number of species. Even for the relatively well- environments are claimed as the most important factors investigated Mediterranean Sea, knowledge mostly relates that strongly shape cave communities (Harmelin, 1986, to caves of the western European coasts (Harmelin, 1969, 2000; Bianchi & Morri, 1994; Bussotti et al., 2006 inter 1985, 1986, 1997, 2000; Harmelin et al., 1985; Balduzzi alias). These factors usually show a distinct negative et al., 1989; Di Geronimo et al., 1993; Taddei Ruggiero, gradient inward the caves. Water infl ow and hydrodynamic 1994; Taddei Ruggiero et al., 1996; Martì et al., 2004 inter energy control oxygen and food availability, maintaining alias), while data on central and eastern sectors is still existing populations, and favouring the diffusion of larvae fragmentary and some studies deal with single taxonomic coming from the outside. Specifi cally, colonisation of groups (Di Geronimo et al., 2000; Sanfi lippo & Mòllica, karstic coastal submarine caves is initially produced 2000; Bussotti et al., 2006; Denitto et al., 2007; Pitruzzello by larvae from neighbouring shelf and adjacent slope & Russo, 2008; Rosso et al., 2012). Nearly nothing is entering the caves after their fl ooding caused by land/sea known about thanatocoenoses and their relationships with interactions, during the post Würmian sea-level rising communities (Monteiro-Marquez, 1981; Di Geronimo et ISSN 0375-7633 doi:10.4435/BSPI.2013.18 ii Bollettino della Società Paleontologica Italiana, 2013 al., 1993, 1997, 2000; Rosso et al., 2012), though they are with a 10 m wide entrance opening between 17 and 30 informative about cave’s colonisation history. m in depth. The floor rises inward roughly following In this context, and taking into account that Sicily is the stratification, ending in a partly subaerial chamber. a region rich in submarine caves still poorly known, the Collapsed blocks, accumulated at places on the floor, present paper aims to: 1) contribute to the knowledge of partly obstruct the entrance. Coarse sediments cover the cave communities from W and E Sicily employing the floor, and their rippled surfaces in the outer zones point main skeletonised sessile invertebrates (and therefore to bottom currents. the most adequate taxa for a comparison with the Living and dead specimens (thanatocoenoses) were thanatocoenoses); 2) explore hard surfaces (walls and examined from 14 selected sites (Fig. 1), two sites from vaults) as well as soft sediments for both living and both the FI and the MZ Caves and five sites from both dead communities; 3) categorise all species found into the GM and the GR Caves. Generally, from each site, ecological groups; 4) test the proposed species categories rocky substrates from the vault and the walls plus bottom as a possible tool to interpret fossil cave communities and sediments were collected, except at the entrances where compare present day caves using thanatocoenoses. the sampling concerned only hard surfaces. Conversely, only sediment samples were taken from the “old” site at the GM Cave and from the FI Cave. Further details on the MATERIALS AND METHODS examined caves, sampling methods and associated faunas can be found in Di Geronimo et al. (2000), Pitruzzello & Materials come from four selected submerged marine Russo (2008) and Rosso et al. (2012). caves (Fig. 1): the Ficarella Cave (FI) located on the E Analysis was focused on three main taxonomic groups: coast of the Capo S. Vito headland, W of Palermo (NW serpuloideans, bryozoans and brachiopods. Sicily, Tyrrhenian Sea), and the Gymnasium (GM), Low magnification images were taken through a Mazzere (MZ) and Granchi (GR) Caves, located in Zeiss Discovery V8A stereomicroscope equipped with different settings along the Maddalena Peninsula, in the an Axiocam MRC and Axiovision acquisition system; Plemmirio Marine Protected Area (PMPA), S of Syracuse SEM images were performed with a LMU Tescan Vega (SE Sicily, Ionian Sea). The PMPA caves open in a Tertiary Scanning Electron Microscope at the Università di Catania carbonate succession and develop sub-horizontally, and a Jeol JSM5310 at the CISAG of the Università di following the rock layering. Caves are elongated, with Napoli “Federico II”. length ranging from 35 m to 65 m. They share blind Materials belong to the Rosso (bryozoans) and ends and a unique entrance, located at about 20 m in Sanfilippo (serpuloideans) collections, deposited at the depth, 3-8 m wide and 1.5-3 m high. The cave vaults do Sezione Paleontologica of the Museo di Scienze della not exceed 3.5 m in height; the floors are nearly flat and Terra of the Università di Catania (PMC). Brachiopods are largely covered by muddy deposits with an abundant housed at the Università di Napoli “Federico II”, Taddei coarser bioclastic fraction. The FI Cave is 130 m long collection (NPMT.R). Fig. 1 - Studied submarine caves and their location in northwestern