the Atlantic. This contrasts sharply with the current setting, where strong NorthSouth barriers separate the Pacific Ocean from the Atlantic, and the AtlanticMediterranean domain from the Indian Ocean. During the Eocene, the biota of the
Tethys Ocean was a tropical-type community of warm waters whose current representatives are mostly found in coral reefs of the Indian and Pacific oceans. The
Oligocene communities of Tethys differed, biogeographically, largely from those of
the Eocene, due to the disappearance of a large number of genera and the appearance
of others with Atlanto-Mediterranean affinities that we can find nowadays in the
Mediterranean (Cappetta and Ledoux 1970). Vestiges of the fish fauna of this Tethys
can be found in species that, geographically, currently occur both on the American,
Mediterranean, or Asian coasts, such as Blennius cristatus and Zeus faber (together
with their related species), as is also the case of the genera Pagrus, Sparus, Echelus,
and Cepola (Quignard 1978).
The final closure of the Tethys seaway, called the Terminal Tethyan Event (TTE),
took place during the first half of the Neogene period, approximately 12–18 My BP,
affecting mainly the eastwards communication with the Indian Ocean, probably with
recurrent re-establishment and interruptions of the connexion, and giving place to
the Paleomediterranean Sea (Steininger and Rögl 1979). Although the Red Sea
started opening about 24 My BP (Segev et al. 2017), when rifting occurred between
the African and the Arabian plates, and received its first waters from the Tethys Sea,
it seems to have never restored a seaway into the Paleomediterranean from the Indian
Ocean, despite a tantalizing isthmus of only 13 m above sea level. The significant
impact of the TTE on circumtropical biota has been widely recognized (Harzhauser
et al. 2007).
To the West, reasonable communication with the Atlantic Ocean persisted for
several million years after the TTE. The Paleomediterranean communicated with the
Atlantic by two straits (Martín et al. 2014): the Betic Strait (occupying part of the
current valley of the Guadalquivir) to the north and the Rifian Strait to the south of
the Betic-Rif arc. The biotic composition of that sea was very different from now,
with most of its flora and fauna still direct inheritances of the Tethys Sea, and with
numerous fossil occurrences of coral reefs (Perrin and Bosellini 2013).
Continued compression and sedimentary infilling triggered the closure of these
straits (Krijgsman et al. 1999; Rouchy and Caruso 2006; Martín et al. 2014),
isolating the Paleomediterranean Sea from the World oceans in the Messinian
(upper Miocene). The Mediterranean Sea started then as a concentration basin,
i.e. the contributions of rivers and precipitation did not balance the evaporation
losses. Therefore, a process of gradual and almost complete desiccation of the
Mediterranean Sea occurred in less than thousand years. This is the renown but
still not fully understood “Messinian Salinity Crisis”, which affected the Mediterranean in a brief but drastic episode, dated 5.97–5.33 My BP. There is still no
agreement as to whether the whole basin dried out (Hsü et al. 1973), or if the
deposition of hundreds of metres of salt and gypsum layers occurred within a deep
sea basin (see revision in Krijgsman et al. 2018), but in any case the impact on the
biota could be so great as to wipe out the Tethyan heritage of biota across the whole
basin. Pérès and Picard (1964) mention, however, the existence of a relic
11 Biogeographical and Macroecological Context of the Alboran Sea
433
Tethys Ocean was a tropical-type community of warm waters whose current representatives are mostly found in coral reefs of the Indian and Pacific oceans. The
Oligocene communities of Tethys differed, biogeographically, largely from those of
the Eocene, due to the disappearance of a large number of genera and the appearance
of others with Atlanto-Mediterranean affinities that we can find nowadays in the
Mediterranean (Cappetta and Ledoux 1970). Vestiges of the fish fauna of this Tethys
can be found in species that, geographically, currently occur both on the American,
Mediterranean, or Asian coasts, such as Blennius cristatus and Zeus faber (together
with their related species), as is also the case of the genera Pagrus, Sparus, Echelus,
and Cepola (Quignard 1978).
The final closure of the Tethys seaway, called the Terminal Tethyan Event (TTE),
took place during the first half of the Neogene period, approximately 12–18 My BP,
affecting mainly the eastwards communication with the Indian Ocean, probably with
recurrent re-establishment and interruptions of the connexion, and giving place to
the Paleomediterranean Sea (Steininger and Rögl 1979). Although the Red Sea
started opening about 24 My BP (Segev et al. 2017), when rifting occurred between
the African and the Arabian plates, and received its first waters from the Tethys Sea,
it seems to have never restored a seaway into the Paleomediterranean from the Indian
Ocean, despite a tantalizing isthmus of only 13 m above sea level. The significant
impact of the TTE on circumtropical biota has been widely recognized (Harzhauser
et al. 2007).
To the West, reasonable communication with the Atlantic Ocean persisted for
several million years after the TTE. The Paleomediterranean communicated with the
Atlantic by two straits (Martín et al. 2014): the Betic Strait (occupying part of the
current valley of the Guadalquivir) to the north and the Rifian Strait to the south of
the Betic-Rif arc. The biotic composition of that sea was very different from now,
with most of its flora and fauna still direct inheritances of the Tethys Sea, and with
numerous fossil occurrences of coral reefs (Perrin and Bosellini 2013).
Continued compression and sedimentary infilling triggered the closure of these
straits (Krijgsman et al. 1999; Rouchy and Caruso 2006; Martín et al. 2014),
isolating the Paleomediterranean Sea from the World oceans in the Messinian
(upper Miocene). The Mediterranean Sea started then as a concentration basin,
i.e. the contributions of rivers and precipitation did not balance the evaporation
losses. Therefore, a process of gradual and almost complete desiccation of the
Mediterranean Sea occurred in less than thousand years. This is the renown but
still not fully understood “Messinian Salinity Crisis”, which affected the Mediterranean in a brief but drastic episode, dated 5.97–5.33 My BP. There is still no
agreement as to whether the whole basin dried out (Hsü et al. 1973), or if the
deposition of hundreds of metres of salt and gypsum layers occurred within a deep
sea basin (see revision in Krijgsman et al. 2018), but in any case the impact on the
biota could be so great as to wipe out the Tethyan heritage of biota across the whole
basin. Pérès and Picard (1964) mention, however, the existence of a relic
11 Biogeographical and Macroecological Context of the Alboran Sea
433