1. The Historical Background
1.1 The Tethys and the Origins of the South West Asiatic Barrier
In order to appreciate the subject of the present monograph, one needs an
understanding of the historical perspective back to the time of the Tethys Sea.
This might seem purely academic, but the worldwide circumtropical marine
connection which ceased to exist about 12 million years ago is the methodological
baseline for the marine zoogeographical processes in our area.
The very existence of the question is based on two fundamental misunderstandings: first, there never was a homogenous Tethys fauna at the species level
which extended all around the tropical belt. Even in the "golden age" of the
Tethys, there were well-established provinces with vicariant species within this
belt. The second misunderstanding is related to the antiquity of the breakup of the
Tethys and the extreme environmental changes which followed: there is absolutely no possibility of any conspecific populations surviving in situ on both sides
of the faunal divide of South West Asia.
Nevertheless, the existence of"Tethys relicts" has time and again been accepted
by different authors: Kosswig (1942), Tortonese (1951), Steinitz (1951), Ekman
(1967), Klausewitz (1968), Kosswig (1967) and de Lattin (1967). Upon closer scrutiny ofthe articles by these authors, one fmds that there are actually no examples
of conspecific relicts given, and so-called relicts are merely representatives of
tropical genera still found today in the Mediterranean.
Ekman (1967, p.88) states carefully: "As regards the Mediterranean, the term
("Tethys relicts") should imply that the organisms in question owe their presence
in this sea solely to the former extent of the Tethys Sea in the Mediterranean and
that they cannot have died out there ... and afterwards migrated into it". Nevertheless, in the same paragraph it folIows: " ... The number of real Tethys relicts
may, however, be not inconsiderable".
Kosswig (1956, p. 86) states, concerning the Mediteranean: "There are grounds
for supposing that the ancient tethic fauna has entirely disappeared ... ". However,
the same author (1967, p.322) admits the possibility that the fish Aphanius dispar ... "left colonies behind it in Palestine during its retreat towards the Indian
Ocean before the closing of the Mediterranean in the East".
Let us now discuss the facts. A marine contact-ofthe Mediterranean with the
central Indian Ocean existed through South West Asia and northern India until
sometime in the first half of the Miocene (Fig.2). Even then, there were clear
differences on the species level between the Mediterranean-South West Asiatic
1.1 The Tethys and the Origins of the South West Asiatic Barrier
In order to appreciate the subject of the present monograph, one needs an
understanding of the historical perspective back to the time of the Tethys Sea.
This might seem purely academic, but the worldwide circumtropical marine
connection which ceased to exist about 12 million years ago is the methodological
baseline for the marine zoogeographical processes in our area.
The very existence of the question is based on two fundamental misunderstandings: first, there never was a homogenous Tethys fauna at the species level
which extended all around the tropical belt. Even in the "golden age" of the
Tethys, there were well-established provinces with vicariant species within this
belt. The second misunderstanding is related to the antiquity of the breakup of the
Tethys and the extreme environmental changes which followed: there is absolutely no possibility of any conspecific populations surviving in situ on both sides
of the faunal divide of South West Asia.
Nevertheless, the existence of"Tethys relicts" has time and again been accepted
by different authors: Kosswig (1942), Tortonese (1951), Steinitz (1951), Ekman
(1967), Klausewitz (1968), Kosswig (1967) and de Lattin (1967). Upon closer scrutiny ofthe articles by these authors, one fmds that there are actually no examples
of conspecific relicts given, and so-called relicts are merely representatives of
tropical genera still found today in the Mediterranean.
Ekman (1967, p.88) states carefully: "As regards the Mediterranean, the term
("Tethys relicts") should imply that the organisms in question owe their presence
in this sea solely to the former extent of the Tethys Sea in the Mediterranean and
that they cannot have died out there ... and afterwards migrated into it". Nevertheless, in the same paragraph it folIows: " ... The number of real Tethys relicts
may, however, be not inconsiderable".
Kosswig (1956, p. 86) states, concerning the Mediteranean: "There are grounds
for supposing that the ancient tethic fauna has entirely disappeared ... ". However,
the same author (1967, p.322) admits the possibility that the fish Aphanius dispar ... "left colonies behind it in Palestine during its retreat towards the Indian
Ocean before the closing of the Mediterranean in the East".
Let us now discuss the facts. A marine contact-ofthe Mediterranean with the
central Indian Ocean existed through South West Asia and northern India until
sometime in the first half of the Miocene (Fig.2). Even then, there were clear
differences on the species level between the Mediterranean-South West Asiatic