Allopolyploidisation in a geological collision zone: on the origin of the tetraploid Anthemis cupaniana Nyman (Compositae, Anthemideae) in Sicily

Abstract

The genus Anthemis has a circum-Mediterranean distribution and comprises c. 175 annual, biennial, and perennial species with polyploid species and species complexes found in its section A. sect. Hiorthia. In Sicily, the genus is represented by 13 species, one of these being the tetraploid A. cupaniana, which is endemic to the island and is distributed throughout the limestone mountains at elevations between 500 and 1800 m a.s.l. Discordant positions in phylogenetic trees based on two plastid regions (psbA-trnH and trnC-petN) and on one nuclear marker (nrDNA ITS1 + 5.8S + ITS2) reveal that the species is of allopolyploid origin, with the maternal parent from the species group around A. cretica and the paternal one from a monophyletic group comprising mostly N African representatives around A. pedunculata. Owing to the fact that the latter group also comprises the Sicilian perennial and diploid A. ismelia and that A. cretica has been found with diploid populations in the C Sicilian Madonie Mts, these two species are considered being the most probable parental diploids of A. cupaniana. The close relationship of A. ismelia with the N African A. pedunculata group supports the biogeographical interpretation of A. cupaniana being the result of a ‘collision’ between diploids from the southern (African) and northern (Eurasian) platforms after dispersal along a Pleistocene corridor in the Sicilian channel.

Karyomorphology of two subspecies of Anthemis maritima (Asteraceae) from Algeria

“…bolosii and another related species. Knowing that hybridization between related Anthemis species is not new as evidenced by various studies (Uitz 1970;Mitsuoka and Ehrendorfer 1972;Nagl and Ehrendorfer 1974;Oberprieler 1998;Oberprieler 2001;Tison and De Foucaul 2014;Oberprieler et al 2022b). This is also the case for the tetraploid A. cupaniana, which is native to Sicily, and has been shown to be the result of allopolyploidization (during the pleistocene).…”

“…Furthermore, A. pedunculata and A. maritima, are the only species that exhibit both diploid and tetraploid cytotypes. Phylogenetic investigations have also shown that the two com-plexes are closely related (Oberprieler 2001;Presti et al 2010;Oberprieler et al 2022b). The similarity in terms of chromosome size and type between the karyotypes of both subspecies leads us to propose the following hypothesis: the tetraploid cytotype of A. maritima may have resulted from either duplication (autopolyploidy) of the diploid cytotype of A. maritima subsp.…”

“…This is also the case for the tetraploid A. cupaniana, which is native to Sicily, and has been shown to be the result of allopolyploidization (during the pleistocene). Specifically, this involved a maternal parent from the A. cretica group and a paternal parent from the North African complex A. pedunculata (Horthia section), namely the diploid Sicilian A. ismelia (Oberprieler et al 2022b).…”

Lectotypification of Anthemis aetnensis (Asteraceae)

“…Anthemis L. (Asteraceae subfam. Asteroideae) in cludes around 175 species in the Mediterranean re gion and adjacent areas (Oberprieler et al, 2022a). Its geographical distribution comprises almost all of west ern Eurasia, northern Africa, the Mediterranean Basin, and a small part of eastern Africa (Lo Presti et al, 2010).…”