This is a small area in northern Iran, from the Caucasian-Euxino-Hyrcanian province of the Euro-Siberian region (Frey and Probst 1986). The district is limited to the Alborz Mountain and Caspian Sea, stretches from Talesh in Azarbaijan in the west to Gorgan in the east and characterized by predominantly deciduous forests.

The district is considered as one zone (Caspian zone) in this study. Fifteen endemic planthoppers of Iran have been recorded from this zone, 9 of which are endemic to the region (Table 1 and Fig. 2). The high and wall-like Alborz Mountain separates the south coast of the Caspian Sea from the Irano-Turanian region. This barrier not only prevents the fauna from migrating to south parts but also limits the high humidity of the Caspian Sea to the north and produces two very different climatic regions in the northern and southern slopes which can be considered a major factor for differentiating the fauna of north Iran from other parts of the country. Most of the Iranian endemic species common between Hyrcanian and other regions are limited to the Alborz Mt. and are distributed in areas very close to the borders of the Hyrcanian district. Malenia masirica Dlabola, 1986 (Derbidae) is the only endemic planthopper recorded in all three main regions. There are only a few records of the presence of this species in Iran which belong mostly to the southern Zagros, the Nubo-Sindian region, close to Irano-Turan, and one record of a female specimen from the north of Iran, all made by Dlabola (1986), and the specimens are deposited in Prague. Morsina persica Melichar, 1902 (Nogodinidae) is the only endemic planthopper common between the Caspian zone and the Nubo-Sindian in spite of the distance and lack of records in the Irano-Turanian. The species was originally described from south east of Iran by Melichar (1902) and there are also other published and unpublished records of this species from there, deposited in HMIM. However the only record of the presence of this species in the Hyrcanian district is made by Dlabola (1981) and he mentioned the species as an eremian faunal element which can be often found as oreal. According to this reference, the only specimen of this species from the north of Iran belongs to the museum of Plant Pests and Disease Research Institute, Tehran-Evin which is the former name used for HMIM, while it is not mentioned in the list of museum specimens (Mirzayans 1995) and is not currently existing in this museum either. However another specimen of this species is deposited in the HMIM museum collected from southeast of Iran, by the same collector and in the same date mentioned by Dlabola’s northern specimen. Therefore the presence of this species in the Hyrcanian district is doubtful and appears to be a mistake in recording the locality in Dlabola (1981).

Historically, the north of Iran was occupied by the old Tethys 55-20 mya (Ghorbani, 2002) so the occupation should have occurred after the area got dry. During the Pliocene ice age (100, 000 years ago) the region was used as a refugee, and species spread northwards after the ice age, which may be a reason for rather small numbers of endemic species in this region. Hedge and Wendelbo (1978) also indicated rather small numbers of endemic Phanerogamic plants in this area. However the area has a considerably different climate and fauna from other parts of Iran and has been considered as a separate zoogeographic division both by Zarudny (1911), Anderson (1968) and Emeljanov (1974).

According to Zohary (1973), the west of Iran is touched by the Saharo-Arabian region. Short and mild winters and long and dry hot summers are typical for this part of the country (Frey and Probst 1986). Two endemic planthoppers of Iran (Callodictya kazeruna (Dlabola, 1986) (Dictyopharidae) and Phantia helleri Linnavuori, 1962 (Flatidae)) have been recorded from this part while the former is in common with other parts of the Irano-Turan (Zagros Mt.) and the latter has a rather wide distribution in the Irano-Turanian and Nubo-Sindian regions (Fig. 2). Hence this region is not considered as an endemic zone in distribution patterns of endemic planthoppers.

The region covers nine tenths of the land of Iran and major parts of the Iranian Plateau, from central to south of Asia. The region consists of plains, deserts and mountains which are divided into 8 primary divisions in this study: Kerman, Karkas Mt., Humid Zagros, Dry Zagros, North Khorasan Mt., South Khorasan Mt., Southern slopes of Alborz Mt. and Deserts and Plains.

Kerman Mountains

The complex of the Kerman Mts located in the southeast of the Irano-Turanian region and partially in the Nubo-Sindian (Fig. 1). The mountain range is a part of the Zagros chain but far from the other mountains and surrounded by deserts. The mountain and the deserts around have been considered as a zoogeographic zone by Zarudny (1911). Twenty eight endemic planthoppers of Iran were recorded from this mountain range, 8 of which endemic for there (Table 1, Fig. 3). The mountain range appears to be rather isolated from the Zagros and is limited by the Jazmurian lowlands in the south, Dasht-e Lut kavirs and other Irano-Turanian plains on the other sides. The isolation of mountains by plains and deserts creates a rather suitable condition for isolating populations and speciation. The high mountains in this complex (eg.: Hezar: 4, 465 m, Lalehzar: 4, 351 m, Tang-e Dalfard, 3, 348 m) may be convenient places for relict species after the cold temperature of the Pleistocene ice age. However the fauna of endemic species is rather affected by both Nubo-Sindian (19 common species) and other parts of Irano-Turan (10 common species) (Fig. 3).

Figure 3.

Venn diagrams for the number of endemic species in Kerman Mts and other areas with common species.

Zagros mountains (Humid and Dry Zagros and Karkas Mt.)

The Zagros mountain chain stretches from northwest of Iran to southeast near the Strait of Hormoz and is considered as the south branches of the Alpine-Himalayan orogenic belt (Dewey et al. 1986). The formation of the Zagros orogenic belt is subjected to controversy. Some geologists believe it has been made by the collision between the Afro-Arabian and Eurasian plate during the Cenozoic (Takin 1972, Agard 2005). As a result of this collision, several parallel folds were formed (Alan, 1969). The long mountain chain divides the Mediterranean climatic zone from the arid regions of west Asia. It is also a barrier between Mesopotamia and the Plateau of Iran with some corridors for the distribution of the fauna between the two zones (Anderson 1968).

In this study the Zagros chain was divided into 3 primary zones (Fig. 1): “Humid Zagros” in the northwest which consists of higher mountains and is affected by Mediterranean winds, “Dry Zagros” in the southeast with a drier climate and rather isolated mountains as the result of wider parallel valleys, and the Karkas mountain which appears to be a rather isolated mountain surrounded by Maranjab kavir and other lower lands around. Two different zones in northwest and southeast Zagros are also applied by Hedge and Wendelbo (1978) for distribution patterns of endemic phanerogamic plants, named: Armeno-Kurdic and Zagros, respectively. Similarly, Zarudny (1911) recognized the northwest of Zagros as a separate zone with a fauna similar to the Caucasus. Northwest of Zagros, (Armenian) was mentioned as a different area from southeast of Zagros, (Zagrossan) in Emeljanov (1974) as well. However both of them were considered as divisions of “Middle Eastern mixed”.

A total of 36 endemic planthoppers of Iran have been recorded from Zagros Mts, 19 of which are endemic to the Zagros (Table 1), 17 endemic to Dry Zagros, and 2 in common with Dry Zagros and Karkas Mt. or Humid Zagros (Fig. 4). The Venn diagram (Fig. 4) shows there are no endemic species for Humid Zagros and Karkas Mt. and the fauna of Iranian endemic planthoppers in those primary zones are mainly in common with Dry Zagros and partially with the south Alborz and Caspian zones. Therefore, those two primary divisions of the Zagros Mountains are not considered as endemic zones. Differently from the wall-like Alborz Mt., the Zagros chain comprises series of parallel ridges and valleys. The distances between mountains increases from northwest to southeast. Although the wider lower lands between the mountains in the south of Zagros (Dry Zagros) form corridors for the distribution and migration of species, mountains surrounded by those lower lands can provide a vicariant condition for speciation or at least prevent the distribution of species to other locations. The fauna of endemic planthoppers in Dry Zagros has some species in common with the Nubo-Sindian (10) and Kerman Mt. (2) which can be explained by the rather short distance between them.

Figure 4.

Venn diagram for the number of endemic species in Zagros Mts. (Humid Zagros, Dry Zagros and Karkas Mt.) and other areas with common species.

Khorasan mountains

It is believed that Iran has been connected to central Asia since the Oligocene. Then the plateau of Iran was uplifted during the Tertiary orogeny and consequently Kope Dagh (Northeast of Iran), Hindukush and Himalaya were created (Anderson 1968). Mountains in northern Khorasan are a continuation of the Alborz but lack the wall-like integration of the Alborz and the humidity of the Caspian Sea, and mountains in both northern and southern Khorasan are rather parallel with the Zagros. In this study they were considered as different primary zones due to their distances and the distribution of endemic planthoppers.

A total of 11 Iranian endemic planthoppers have been recorded from Khorasan Mts, 5 of which are endemic to this mountain range (Table 1), 3 in the south, 1 in the north and 1 in common (Fig. 5). The cluster analysis shows the similarity of the northern and southern fauna (Fig. 6). Hence the two mountains can be considered as a same zone in the distribution pattern. While south parts, which are surrounded by Kavir-e Lut and Dasht-e Kavir to the west and lowlands in Afghanistan to the east, have more endemic species and appear to be more suitable places for speciation.

Figure 5.

Venn diagram for the number of endemic species in Khorasan Mts and common species with other areas.

Figure 6.

Cluster diagram for the endemic areas of Fulgoromorpha in Iran.

Southern slopes of Alborz

The Alborz mountain chain represents a north branch of the Alpine-Himalayan orogenic system (Dewey et al. 1986). It stretches from northwest of Iran to southeast of the Caspian Sea and includes the highest mountain of west Asia, Damavand 5, 670 m. It forms a consistent barrier between the fauna of the Caspian zone and the Plateau of Iran.

Seventeen endemic planthoppers of Iran are recorded from the south of Alborz, 12 of which endemic to the region (Table 1, Fig. 7). The southern slopes of Alborz have an absolutely different climatic condition from the northern Slopes due to the lack of corridors for receiving the humidity of the Caspian Sea. The presence of the Dasht-e Kavir desert in the south can be another factor for preventing the distribution of populations and probably speciation. There is only one common endemic planthopper between the southern slopes of Alborz and northern Khorasan whereas three species in common with the Zagros show a relationship with the western mountains.

Figure 7.

Venn diagram for the number of endemic species in southern slopes of Alborz and common species with other areas.

This part of the country in southern and southeastern Iran is the only region which is not considered as Palaearctic but as a part of the Oriental. A varied terminology has been used for this region. Hedge and Wendelbo (1978) used the term “Sahara-Sindian” to show a west to east continuum from southwest Asia to Send deserts while Frey and Probst (1986) preferred Nubo-Sindian because they believed the distribution patterns of the Nubo-Sindian province are obvious here while Saharo-Arabian and Mediterranean species have migrated to this region.

By subtracting the endemic species of a small part of the Kerman Mountain from the Nubo-Sindian, 54 recorded endemic species of Iran, which is more than half of the total, are distributed in this region and 32 of these are endemic to the region (Table 1). The distribution of endemic Fulgoromorpha shows three rather separate groups which are recognized as three primary zones here: Baluchestan, the Strait of Hormoz and the coasts of the Persian Gulf (Fig. 1). The cluster analysis showed the similarity of the fauna of the endemic species in the Strait of Hormoz and the Persian Gulf coasts (Fig. 8) so those two primary zones can be considered as a same zone. Anderson (1968) found a discontinuity in the faunal elements of southern and southeastern Iran and justified it with the relatively recent position of the Persian Gulf and lower sea levels during the Pleistocene which must have caused dry land contact between Iran and Arabia. This belief is confirmed by evidence for ecological continuity across the two sides of the Persian Gulf. Therefore the higher sea levels after the ice age can also produce a vicariant condition in the Persian Gulf coasts and isolating endemic species between mountains and a different climate condition to the north and the waters of the Persian Gulf to the south. The number of endemic species in the Nubo-Sindian is reduced from east to west which may be because of the isolation of the eastern species by the Kavie-e Lut and Jazmurian lowlands. On the other hand, the Venn diagram (Fig. 9) shows a rather high number of common species between Baluchestan and the two other adjacent areas. Hence according to our current knowledge of distribution patterns of endemic planthoppers, the Baluchestan primary zone can also be united with the other primary zones of the Nubo-Sindian region. The area was also considered mainly as one division (Makran mixed) with a very small area of Baluchestan in southeast (Sind plane) by Emeljanov (1974). According to Ghorbani (2002), some parts of Baluchestan, the Strait of Hormoz and the area between them had been occupied by the old Tethys so the common endemic species between Baluchestan and two other primary zones in southern Iran should have crossed the area after drying.

The final 6 endemic zones (Caspian zone, South slopes of Alborz, Khorasan Mts, Zagros Mts, Kerman Mts and Baluchestan and Persian Gulf coasts) are shown in Fig. 10. The cluster analysis on six final endemic zones of Iranian planthoppers (Fig. 6) indicates Baluchestan and Perisan Gulf coasts the only region which is considered as a part of the Oriental Region, as the most different zone from the others. Then Zagros Mts, Kerman Mts, Alborz, Khorasan Mts and Caspian zones are diverging, respectively. Alscal analysis produced a map according to the similarity of endemic zones. Rotating the similarity map canvas horizontally (Fig. 11), makes it more comparable with the geographic map (Fig. 10). The Caspian zone and the Nubo-Sindian region are located in similar situations in both maps. While the Khorasan zone is closer to the Caspian zone in the similarity map rather than its geographic situation. This similarity can be justified by the possibility of specimens migrating between two zones at the end of the wall-like mountains of Alborz at the east of the Caspian zone. This is why the southern slopes of Alborz go farther in the Alscal map and confirms the efficiency of the barrier of the Alborz mountain in separating species of the two adjacent zones. Although the Zagros mountain has rather similar situations in both maps, it is farther from the Nubo-Sindian in similarity rather than its geographic situation. The reason may be the higher number of endemic species in Baluchestan rather than in the coasts of Persian Gulf and the Strait of Hormoz close to the Zagros Mountains. The situation of the Kermann Mts in the similarity map moved from its geographic situation towards the north. The rather far distance of this zone from the others, confirms the isolation of the species living there. However, deleting the doubtful record of Morsina persica, common between the Caspian zone and the Nubo-Sindian part of the Kerman Mountains may move the situation of the Kerman zone in the similarity map towards the south.

The records of the endemic planthoppers of Iran belong to recent 110 years (Mozaffarian and Wilson 2011). The nature of Iran, like any other land, has been exposed to various changes during this long period by events, such as agriculture, war, fire in woods and forests, overgrazing, urbanization and so on. Hence, probably the presence of some endemic species with a limited distribution and the probable extinction of some of them should be subjected to further investigations.