AÇOREANA, 2014, Suplemento 10: 109-116 NEW RECORDS OF MARINE WOOD BORERS (BIVALVIA: TEREDINIDAE AND ISOPODA: LIMNORIIDAE) FROM SÃO MIGUEL, AZORES, WITH A DISCUSSION OF SOME ASPECTS OF THEIR BIOGEOGRAPHY Luísa M.S. Borges & Filipe O. Costa Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal e-mail: luisaborges2000@yahoo.co.uk Helmholĵ-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung GmbH, Max-Planck-Straße 1, 21502 Geesthacht, Deutschland/Germany ABSTRACT Specimens of the morpho-species Lyrodus pedicellatus (Bivalvia: Teredinidae) and Limnoria tripunctata and L. quadripunctata (Isopoda: Limnoridae) were extracted from wood samples collected during July 2012. Limnoria tripunctata and L. quadripunctata coexisted in the same wood piece, which is rare for limnoriids. All three species were recorded for the first time from São Miguel waters and L. quadripunctata was also recorded for the first time from the Azores. The recent recorded presence of these species in the Azores suggests a recent range expansion from southern Europe. RESUMO Espécimes da morfo-espécie Lyrodus pedicellatus (Bivalvia: Teredinidae) e espécimes das espécies Limnoria tripunctata e L. quadripunctata (Isopoda: Limnoriidae) foram extraídos de pedaços de madeira coletados durante o Workshop Sabrina, Mosteiros, São Miguel, Açores. L. tripunctata e L. quadripuncta foram encontradas a coexistir no mesmo pedaço de madeira, o que é uma observação rara em limnorideos. Este é o primeiro registo para estas três espécies em São Miguel e também o primeiro registo da espécie L. quadripunctata nos Açores. A ocorrência destas três espécies nos Açores, coincidente com o aumento da actividade destes organismos na última década na Europa, sugere uma recente expansão com origem no Sul da Europa. INTRODUCTION M arine wood borers are an heteregeneous group of xylotrophic (wood feeding) organisms, including bivalves (Teredinidae [Distel, 2003]) and Crustacea (Limnoriidae [Cragg, 2003]). They are considered serious pests due to the destruction they inflict on man- made wooden structures in the marine environment (Turner & Johnson, 1971). Indeed, economic and safety issues were the main motivation for the first scientific studies of the species in the 18th century, when outbreaks of wood borers in the wooden dykes of the Netherlands caused catastrophic destruction. Among the numerous reports produced on wood borers at the time (Clapp & Kenk, 1963), the most important was that of Sellius (1733) wherein he recognised three teredinid species, which were synonymised by Turner (1966) with Teredo navalis (Linnaeus, 1758), Nototeredo norvagica (Spengler, 1792) and Psiloteredo megotara (Hanley, 1848) and an isopod species, which was interpreted to be Limnoria lignorum (Rathke, 1799) (Clapp & Kenk, 1963). Since these early studies, a large number of teredinids have been reported upon from European waters from cold Norway (Santhakumaran & Sneli, 1978; Borges, 2007) to the warm Mediterranean Sea (Bobat, 1995; Borges, 2007; Sivrikaya et al., 2009). The large number of publications describing new teredinid species in the 18th, 19th and early 20th centuries created many synonyms. This situation left the systematics and taxonomy of the Teredinidae in a chaotic state. One of the reasons for this was probably the fact that teredinids are a particularly difficult group of bivalves