Sunday, December 26, 2010

A relic of the Miocene

Asplenium azomanes (synonym of Asplenium trichomanes ssp. coriaceifolium) appeared on Earth as such for about 6 million years in Messinian period of Late Miocene after various hybridization and adaptive mutations. Given its allotetraploid chromosome and phenotypic characteristics is supposed result of hybridization between Asplenium azoricum, endemic to the Azores and a copy of trichomanes complex, perhaps the Asplenium trichomanes ssp. hastatum. In turn, its father Asplenium azoricum also allotetraploid, is the result of hybridization between the ancestral Asplenium anceps, endemic to the Azores, Madeira and the Canary Islands and a copy may be extinct genus Asplenium.

It was described to science in 1991 by Professor of the University of Valencia, born in Banyalbufar (Island of Mallorca, Spain), Josep Antoni Rosselló i Picornell. ( To him I dedicate this article, so much that he has taught me about these small ancestral ferns )

Asplenium anceps, the patriarch of the series, on the island of Madeira to 1,500 m, accompanied by Asplenium Adiantum-nigrum (left) and Polypodium vulgare (right).

Late Miocene, approximately 6 million years, there was a very dry and cold period that lasted a million years, called Messinian, which began to collide the European and African tectonic plates, forming the Betic-Rif Massif which closed passage of water from the Atlantic Ocean into the Mediterranean Sea. At the same time there was a global climate cooling in Antarctica froze and water accumulated on it in ice, lowering the ocean levels by about 100 meters.

The decline in rainfall by global cooling and the absence of water intake from the Atlantic Ocean transformed the Mediterranean into a desert with a few salty lakes. At the same time reducing the water level of the ocean surface made of the land that separated the Macaronesian islands of European and African continents, facilitating the exchange of plant and animal species between islands and continents around the Mediterranean, where the islands were transformed into mountains separated by deep valleys dried (Baleares, Corsica, Sardinia, Sicily, Malta, etc ...), which explains the existence of the Tyrrhenian endemics such as Arum pictum, Arenaria balearica, Asplenium balearicum, Brimeura fastigiata, Dracunculus muscivorus, Soleirolia soleirolii, etc ... and the Atlantic, which also explains the existence of hundreds of species, especially plants and ferns in particular, who live both on the Atlantic coast of the Peninsula Ibérica (Sierra de Sintra in Portugal and Cadiz, Galicia, Asturias and Cantabria in Spain), the Mediterranean and Atlantic coast of West Africa (Morocco, Algeria) and the Macaronesian archipelagos (Azores, Canary Islands, Madeira and Cape Verde), such as Woorwardia radicans, Davallia canariensis, Diplazium caudatum, Asplenium hemionitis, Pistacia atlantica, Euphorbia regis-juba, Astydamia latifolia, Dracaena draco, etc ...

Asplenium azoricum, son of Asplenium anceps and father of Asplenium azomanes on the island of Faial in the Azores Archipelago. It is very striking the phenotype resemblance with its father and its son.

This was because during the previous million years Messinian formed Asplenium azomanes, very adapted to the dry climate, populating the limestone oriented to the north and northwest of this vast region.

Asplenium Azomanes, son of Asplenium azoricum and grandson of Asplenium anceps in calcareous rocks in the town of Ubrique in Sierra de Grazalema Natural Park.

Last million years the Messinian period was the end of the Miocene with climate change, which resulted in global warming, which caused the ice to melt in Antarctica and raise the level of ocean water at about 60 meters . At the same time there was a new movement of European and African tectonic plates that are separated and between them formed a great groove, the Strait of Gibraltar, who broke the Betic-Rif Massif and allowed the water inlet of the Atlantic Ocean to the Sea Mediterranean. The water intake along with increased rainfall from global warming, brought up the water level of the Mediterranean, turning back into mountains the Balearic and Tyrrhenian islands and fragmenting the population of Asplenium azomanes in three regions: the westernmost Balearic Islands ( Mallorca, Ibiza and Formentera), south of the Iberian Peninsula (Cadiz, Malaga, Jaen, Albacete, Murcia and Almeria in Spain and Faro in Portugal) and northern Morocco (from Chefchaouen west of the Rif Mountains to the rocks surrounding the Chameau caves in the Beni Snassen mountains).

Distribution of Asplenium azomanes as 6 million years ago was the Betic-Rif Massif.

Asplenium azomanes in Mallorca has been hybridized with Asplenium trichomanes ssp. quadrivalens and has resulted in a hybrid extremely vigorous, very shade-intolerant and resistant, Asplenium X tubalense (synonym of Asplenium trichomanes nothosubsp. barreraense). This fern produces almost all spores no viable and aborted, but also a fertile diplospore, which explains its abundance in a patch wall Soller Valley.

Vigorous Asplenium X tubalense with fronds about 30 cm, extended into the light, in a wall patch of Sóller. Surprised by the extraordinary resemblance to its Macaronesian grandfather, Asplenium anceps.

Aborted and no viable spores of Asplenium X tubalense with fertile diplospore.

The whole family all the amazing saga of these antediluvian ferns.

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