Complex origins of the Lusitania biogeographic province and northeastern Atlantic fishes

Vítor C Almada,Alberto Brito,Frederico Oliveira Almada,Joana I Robalo,André Levy,Joana Martins,Jesus Falcón Toledo,Sergio R Floeter

doi:10.21425/f55114493

Abstract

The Lusitania Province encompasses the warm temperate marine waters between the southern end of the English Channel, in the North, and Cape Juby or Cape Blanco, in the South, including the Mediterranean and the archipelagoes of the Azores, Madeira and the Canary Islands. Briggs and Bowen (2012) proposed that the warm temperate provinces, although retaining their provincial status, should be grouped with the adjacent tropical ones. Thus, they included the Lusitania Province in a warm eastern Atlantic region. We argue that the time elapsed since the Miocene was sufficient to allow the evolution of endemic species, genera and some higher rank taxa, a finding that emphasizes the convenience to avoid the integration of the province in this larger region. The tropicality index for the Lusitania Province is 1.82, indicating a prevalence of warm water over cold water fish. However, this value is strongly biased by the large differences between the Macaronesian archipelagos (4.08) and the mainland coasts of the Lusitania Province (0.66).

Highlights

The Lusitania Province encompasses the warm temperate marine waters between the southern end of the English Channel, in the North, to Cape Juby (Briggs and Bowen 2012) or Cape Blanco (Spalding et al 2007) in the South, including the Mediterranean and the archipelagoes of the Azores, Madeira and the Canary Islands.Recently, Briggs and Bowen (2012) pro‐ posed that the warm temperate provinces, al‐ though retaining their provincial status, should be grouped with the adjacent tropical ones
The Lusitania Province would be included in a warm eastern Atlantic region (EAR)
This change in bio‐ geographic classification is supported by two argu‐ ments: 1) many warm temperate areas harbor a composite of eurythermic species shared with the adjacent tropical or boreal prov‐ inces; 2) what are warm temperate areas had a tropical environment in the Miocene and were subjected to a complex cooling process that reached its peak in the Pleistocene glacial cycles (Briggs and Bowen 2012)

Summary

Introduction

The Lusitania Province encompasses the warm temperate marine waters between the southern end of the English Channel, in the North, to Cape Juby (Briggs and Bowen 2012) or Cape Blanco (Spalding et al 2007) in the South, including the Mediterranean and the archipelagoes of the Azores, Madeira and the Canary Islands. The Lusitania Province would be included in a warm eastern Atlantic region (EAR) This change in bio‐ geographic classification is supported by two argu‐ ments: 1) many warm temperate areas harbor a composite of eurythermic (and other) species shared with the adjacent tropical or boreal prov‐ inces; 2) what are warm temperate areas had a tropical environment in the Miocene and were subjected to a complex cooling process that reached its peak in the Pleistocene glacial cycles (Briggs and Bowen 2012). Important changes are occurring within the Lusitania Province with the introduc‐ tion of new species with ballast waters, Lessepsian migrants through the Suez Canal affecting faunal composition in the Mediterranean, and a tropicali‐

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