Clinal variation and evolution in the Hutera - Rhynchosinapis complex of the Sierra Morena (south-central Spain)

Abstract

Geographical distribution and phenetic variation are studied for a group of related endemic species at present assigned to the genera Hutera and Rhynchosinapis. The presence of Rhynchosinapis hispida is recorded for five localities on the western part of the range studied. The area of R. longirostra is further explored to give twelve localities over an extended area of 100 km. Five additional localities, to give a total of seven, are also recorded for Hutera leptocarpa, and the limits between the area of this species and that of R. longirostra are tentatively established. Some populations which show intermediate and gradative characters between these taxa are referred to two new varieties and to three new genetic forms. The small area where H. rupestris occurs in the adjoining Sierra de Alcaraz is also explored. A numerical study of ten differential characters over fifteen populations of the above taxa, shows an obvious correlation between phenotype and geographical distribution, and sheds light on their possible phylogenetic relationship. Hutera leptocarpa and Rhynchosinapis longirostra seem to be schizoendemics which have recently and independently evolved from ancestors similar to the more widely distributed R. hispida. Hutera rupestris should not be regarded as a relict, but rather as a recent invader into the adjoining calcareous sierras. No solid basis has been found to maintain two separate genera and so the new combinations Hutera hispida and Hutera longirostra are proposed for the basionyms Rhynchosinapis hispida and Rhynchosinapis longirostra respectively. Conservational aspects are also discussed.