Mediterranean Syllidae (Annelida: Polychaeta) revisited: biogeography, diversity and species fidelity to environmental features

Abstract

The species diversity of Syllidae (Annelida: Polychaeta) on different coastlines within the Mediterranean Basin was analysed, including along the Salento Peninsula (Italy), which is thought to play a crucial role as a crossroads between different biogeographic areas. Analysis of biogeography, the assignment of species into 6 bioclimatic categories, a novel method to assess intermatrix correlation significance and the correlation between species distribution, and some environmental variables provided relevant tools to investigate the influence of a suite of ecological and historical factors on syllid distribution. Data showed that Syllidae could be considered a useful taxon for biogeographic speculations, even though bioclimatic and environmental analyses appeared significantly more informative. The Salento Peninsula revealed an affinity with some eastern Mediterranean coastlines. Syllid distribution suggested the existence of an 'Atlantism' gradient, decreasing eastwards and possibly corresponding to a temperature gradient when bioclimatic categories were analysed. In contrast to previous results, the Eastern and Western Basins did not show great differences in species diversity. The observed differences could, in part, be due to an 'author effect', due to the differing taxonomic updating of the available faunistic lists. Syllidae were found to be effective faunistic and ecological indicators, able to characterize different areas inside the Mediterranean Sea; thus, the present results could be used to stimulate further research on different aspects of the family.

Diversity, distribution and ecology of the family Syllidae (Annelida) in the Portuguese coast (Western Iberian Peninsula)

“…The coarse sand Syllid assemblage here described with Sphaerosyllis bulbosa, Syllis pontxioi and Trypanosyllis coeliaca is part of the coarse sediment macrobenthic community reported by Martins et al (in press), for the Portuguese continental shelf. This is a similar community to the gravels dominated by Astarte sulcata-Venus casina (Glémarec 1973) or the Venus community (Thorson 1957), identified in several European coasts, in Portugal with a high number of warm water species (e.g., Opisthodonta serratisetosa, Palposyllis prosostoma or Syllis licheri) cooccurring with boreal, Atlantic-Mediterranean, amphiAtlantic or cosmopolitan species (e.g., Odontosyllis gibba, Plakosyllis brevipes or Sphaerosyllis bulbosa; Musco and Giangrande 2005;. The fine sand Syllids assemblage dominated by the warm water species Parapionosyllis brevicirra, Syllis mercedesae and S. garciai is part of the Lusitanean macrofauna assemblage found in muddy sands of the southern Portuguese shelf (Martins et al in press).…”

Faunal and biogeographic analysis of Syllidae (Polychaeta) from Rovinj (Croatia, northern Adriatic Sea)

“…Concerning polychaetes, the northern Adriatic Sea hosts the highest percentage of cold-temperate Syllidae species within the Mediterranean, but it also shows the lowest taxonomic updating index (Musco and Giangrande, 2005a). In fact, research on northern Adriatic polychaete fauna started in the second half of the 19th century and continued from the first half of the 20th (see Amoureux, 1983 and literature cited) to the present (Požar-Domac, 1994 and literature cited; Zahtila, 1997;Castelli et al, 1999;Mistri et al, 2002;Aleffi et al, 2003).…”

“…It is also the most diverse polychaete family in the Adriatic Sea, with approximately 100 species (Musco and Giangrande, 2005a). Syllid distribution seems to be a good indicator of local environmental conditions and might be effective in assessing large-scale ecological changes, even over relatively short periods Musco and Giangrande, 2005a).…”

Description of a new species of Sphaerosyllis Claparède, 1863 (Polychaeta: Syllidae: Exogoninae) from the Alicante coast (W Mediterranean) and first reports of two other species of Syllidae for the Mediterranean Sea and the Iberian Peninsula

“…According to Galil (2006) and Por (1978), tropical species have been entering the Mediterranean through either the Suez Canal (Lessepsian migration) or the Strait of Gibraltar for decades. Furthermore, Bianchi & Morri (2003) and Musco & Giangrande (2005) suggested the possibility of a "tropicalisation" trend of the Mediterranean fauna. Another reason could be that the presence of these new reports and the new species is the result of a more intense scientific investigation.…”

“…According to Musco & Giangrande (2005), updating syllid inventories is necessary if aiming to detect possible migrations. In addition, also indicated several possibilities that might explain the ways of introduction of new reports for the Mediterranean Sea in their survey.…”