PHYLOGENY AND HISTORICAL BIOGEOGRAPHY OF LIMPETS OF THE ORDER PATELLOGASTROPODA BASED ON MITOCHONDRIAL DNA SEQUENCES

• Published in: Journal Molluscan Studies
• Main Authors: NAKANO, TOMOYUKI, OZAWA, TOMOWO
• Format: Text
• Language: English
• Published: Oxford University Press 2004
• Subjects: Articles; Antarctic; Pacific; Nacella; Antarc*; Antarctica
• Online Access: http://mollus.oxfordjournals.org/cgi/content/short/70/1/31; https://doi.org/10.1093/mollus/70.1.31

Using new and previously published sequences of two mitochondrial genes (fragments of 12S and 16S ribosomal RNA; total 700 sites), we constructed a molecular phylogeny for 86 extant species, covering a major part of the order Patellogastropoda. There were 35 lottiid, one acmaeid, five nacellid and two patellid species from the western and northern Pacific; and 34 patellid, six nacellid and three lottiid species from the Atlantic, southern Africa, Antarctica and Australia. Emarginula foveolata fujitai (Fissurellidae) was used as the outgroup. In the resulting phylogenetic trees, the species fall into two major clades with high bootstrap support, designated here as (A) a clade of southern Tethyan origin consisting of superfamily Patelloidea and (B) a clade of tropical Tethyan origin consisting of the Acmaeoidea. Clades A and B were further divided into three and six subclades, respectively, which correspond with geographical distributions of species in the following genus or genera: (A1) northeastern Atlantic ( Patella ); (A2) southern Africa and Australasia ( Scutellastra , Cymbula and Helcion ); (A3) Antarctic, western Pacific, Australasia ( Nacella and Cellana ); (B1) western to northwestern Pacific ( Patelloida ); (B2) northern Pacific and northeastern Atlantic ( Lottia ); (B3) northern Pacific ( Lottia and Yayoiacmea ); (B4) northwestern Pacific ( Nipponacmea ); (B5) northern Pacific ( Acmaea and Niveotectura ) and (B6) northeastern Atlantic ( Tectura ). Approximate divergence times were estimated using geological events and the fossil record to determine a reference date. Divergence of the two major clades likely occurred as far back as the early Cretaceous. The phylogeny also suggests that nine principal geographic clades were formed during the late Mesozoic to early Cenozoic in association with the disruption of Pangea, which gave rise to new oceans and seaways.