Can material of a putatively extinct new species of Ruta (Rutaceae), preserved with mummies, provide new knowledge about evolution in the Canary Islands flora?

Abstract

Based on analyses carried out with plant material found in mummy shrouds preserved in the archaeological museum El Museo Canario, a putatively extinct new species of Ruta (Rutaceae) was identified and is described here as R. museocanariensis. The mummies were found in the funerary sites of Acusa and the Barranco de Guayadeque on Gran Canaria, Canary Islands, Spain. This article discusses taxonomic relationships with other species of the genus, aspects of colonization and evolutionary processes on islands. The archaeological plant material consists of vegetative and reproductive branches with leaves, remains of flowers and capsules. Several morphological traits, especially the type of fruits, establish a clear difference between Ruta species from Gran Canaria and the mainland (dehiscent) and species from the W Canary Islands (indehiscent). The discovery of R. museocanariensis, with dehiscent fruits, suggests that indehiscence is a post-colonization evolutionary process in the Canary Islands. It also supports a stepping-stone model of inter-island colonization with Gran Canaria as its starting point, in agreement with the age of the islands and to some extent with their distance from the mainland.