INTRODUCTION

Our knowledge on the malacofauna of historic Palestine is based on old literature (Tristram 1865, Germain 1921–1922, Bodenheimer 1935, Abdel Azim & Gismann 1956). Tristram (1865) recorded several species of the freshwater and land snails from Palestine, Jordan, Lebanon and Syria. Little is known on the diversity of freshwater snail fauna in the Palestinian Territories (West Bank). So far, a total of 10 species belonging to five families have been recorded (Heller et al. 2005, Bdir & Adwan 2012, Handal et al. 2015).

The Palestine Museum of Natural History (PMNH) and Palestine Institute for Biodiversity and Sustainability (PIBS) were established to promote biodiversity research in Palestine (Qumsiyeh et al. 2017). The aim of the current study is to provide new information regarding the freshwater gastropod species diversity in Palestine (West Bank) and expand the knowledge about their distribution.

MATERIAL AND METHODS

Freshwater snails were collected from 35 localities (Table 1, Fig. 1) from the Territories through several field visits to freshwater bodies during 2015–2021. Collected materials were deposited at the Palestine Museum of Natural History collection (PMNH). Freshwater habitats visited include springs, pools, temporary rain pools, water tanks, ponds, irrigation canals and rivers. Samples were collected by hand from underneath rocks, floating vegetation, around the edges or by means of a 2 mm pore size sieve for small-size and mud-dwelling species, since they are larger than 2 mm. All living specimens were preserved in 70% alcohol, while the dry shells were kept in plastic containers.

Table 1

List of sampling sites

Fig. 1

Map of the Palestinian Territories showing collecting sites

RESULTS

A total of 14 species of freshwater snails belonging to eight families (Cochliopidae, Melanopsidae, Neritidae, Lymnaeidae, Physidae, Planorbidae, and Thiaridae) in eleven genera (Bulinus, Eupaludestrina, Heleobia, Galba, Melanoides, Melanopsis, Mieniplotia, Physella, Planorbella, Radix, and Theodoxus) were collected from freshwater habitats in the Palestinian Territories.

Family Neritidae Rafinesque, 1815

Theodoxus jordani (Sowerby, 1844)

Figs 2–3

Figs 2–10

Shells of: 2 – black form of Theodoxus jordani; 3 – straited form of Theodoxus jordani; 4 – Eupaludestrina contempta; 5 – Heleobia sp.; 6 – Melanopsis buccinoidea; 7 – Melanopsis costata costata; 8 – Melanopsis saulcyi; 9 – Melanopsis cerithiopsis; 10 – Melanoides tuberculata. Scale bars – 5 mm (2–3), 3 mm (4–5), 5 mm (6–9), 5 mm (10)

Materials examined:

Distribution. Theodoxus jordani has a wide range of distribution extending from southern Anatolia, Syria, Lebanon, Jordan, Palestine, into Mesopotamia and southern Iran (Sands et al. 2020).

Remarks. Dagan (1971) considered that T. jordani and T. macri are the same species based on that both species have central tooth of common structure and the operculum articulation is identical. However, Roth (1987) reaffirmed the difference between the two species based on morphological evidences. Schütt & Ortal (1993) listed five subspecies of T. jordani recovered from plio-pleistocene sediments in the Jordan Valley; Theodoxus jordani jordani, Theodoxus jordani pliocostulcaus, Theodoxus jordani unicarinatus, Theodoxus jordani bicarinatus and Theodoxus jordani tricarinatus. Dagan (1971) and Bandel (2001) concluded that T. macri is a junior synonym of T. jordani. Sands et al. (2020) recognized T. jordani as a full species with a wide distribution across southern Turkey to southern Iran, and that the genus Theodoxus in Jordan and Palestine is represented by a single species, T. jordani, based on molecular analyses.

According to the map depicted by Sands et al. (2020), the distribution of Theodoxus macri is confined to southwestern Turkey and northwestern Syria. Thus, all previous records for T. macri from Palestine should be considered as T. jordani.

This species prefers clear and fast running water and was found attached to stones (Amr et al. 2014).

Family Cochliopidae Tryon, 1866

Eupaludestrina contempta (Dautzenberg, 1894)

Fig. 4

Materials examined:

Distribution. Jordan, Lebanon, Palestine, and Syria.

Remarks. Schütt (1991) reported this species from four localities in the Dead Sea area (Ein Turabe, En Hakikar, Enot Zuqim, and Enot Qane). This species is associated with springs and wetlands which has slightly saline muddy sediment. They are found attached to roots of aquatic submerged vegetation (Amr et al. 2014). In Jordan, two species are known, Eupaludestrina contempta (Dautzenberg, 1894) and Eupaludestrina longiscata (Bourguignat, 1856).

Heleobia sp.

Fig. 5

Materials examined:

Distribution.: Species of this genus are known from Jordan, Palestine, Syria and Lebanon.

Remarks. Originally, this genus was placed as Semisalsa. Molecular data suggests that species of the genus Semisalsa should be reassigned under the genus Heleobia (Wilke et al. 2001). Milstein et al. (2012) stated that H. phaeniciaca (Pallary, 1939) distributed in humid areas of Palestine is very common. The specimen collected from Nablus-Nabe’ Zawata is similar to Heleobia sp. described by Milstein et al. (2012) by having small and smooth shell.

Family Melanopsidae Adams et Adams, 1854

Melanopsis buccinoidea (Olivier, 1801)

Fig. 6

Materials examined:

Distribution. Jordan, Palestine, Lebanon, Syria, Greece, Cyprus and southern Turkey.

Habitat. Clear freshwater springs and pools. This species is mostly associated with Theodoxus jordani (Amr et al. 2014).

Remarks. Glaubrecht (1993) gave a very comprehensive treatment for the species of the genus Melanopsis in the Mediterranean Basin based on morphometric features. He referred to populations of this genus in Jordan and Palestine as Melanopsis praemorsa buccinoidea and Melanopsis praemorsa costata. Heller et al. (2005), also based on morphological features, recognized M. buccinoidea as the species occurring in Palestine with variations. According to Amr et al. (2014) there are two forms of this freshwater snail; the Levant form (elongated) and the Jordan Valley form.

Melanopsis costata costata (Olivier, 1804)

Fig. 7

Materials examined:

Distribution. Levant and Iran.

Remarks. Heller et al. (2005) stated that four subspecies for this species are known in the Levant; namely M. c. costata, M. c. lampra, M. c. jordani, and M. c. obliqua whereas M. c. obliqua and M. c. jordani are common along the lower and upper Jordan River, respectively. This species is usually found submerged in mud in springs and swamps.

Melanopsis saulcyi (Bourguignat, 1853)

Fig. 8

Materials examined:

Distribution. Jordan, Palestine and Syria.

Remarks. This species differs from other ribbed species (i.e. M. costata) by having more ribs that are bumpy in appearance (Heller et al. 2005). This species is mostly associated with slow running water, usually close to aquatic plants (Amr et al. 2014).

Melanopsis cerithiopsis Bourguignat, 1884

Fig. 9

Materials examined:

Remarks. This species was recovered from archeological sites in Tell Jenin and Jericho (Biggs1963, Ezzughayyar & Swaileh2014). It was found in sympatry with M. buccinoidea in the lower Jordan Valley. Schütt (1987) considered this species as a relict form of Melanopsis that was common between Euphrates and the Jordan Valley. Heller et al. (2005) considered M. cerithiopsis as a synonym of M. saulcyi.

Family Thiaridae Gill, 1871

Melanoides tuberculata (O. F. Müller, 1774)

Fig. 10

Materials examined:

Distribution. Worldwide all over most of Africa, Asia and Australia.

Remarks. Melanoides tuberculata is associated with freshwater bodies (i.e. springs, streams and swamps) that are considered slightly saline. It is considered as a common species within the West Bank, as it is spread alongside the Jordan River Valley, especially around the Dead Sea basin and Jericho district.

Mieniplotia scabra (O. F. Müller, 1774)

Fig. 11

Figs 11–17

Shells of: 11 – Mieniplotia scabra; 12 – Radix natalensis; 13 – Galba truncatula; 14 – Physella acuta; 15–16 – Bulinus truncatus; 17 – Planorbella duryi. Scale bars – 5 mm (11–16), 10 mm (17)

Materials examined:

Distribution. South and Southeast Asia, and the Indo-Australian Archipelago extending eastwards to the western Pacific Islands. It is considered as introduced to the Middle East.

Remarks. This is considered as an invasive freshwater snail to the Palestinian Territories. Heller et al. (2014) found that this was the most common freshwater snail in Lake Tiberias accounting for > 95% of the snails’ populations, affecting native species (i.e. Melanopsis costata, Melanoides tuberculata, Theodoxus jordani and Bithynia phialensis). It was reported from the Jordan River (Nasarat et al. 2014).

Family Lymnaeidae Rafinesque, 1815

Radix natalensis (Krauss, 1848)

Fig. 12

Materials examined:

Distribution. Tropical Africa, Yemen, Oman and Saudi Arabia.

Remarks. This snail is found in marshes, swamps and other different types of steady water bodies (Amr et al. 2014). It is also implicated in the transmission of fasciolosis in different countries in Africa (Brown 1994).

Galba truncatula (O. F. Müller, 1774)

Fig. 13

Materials examined:

Distribution. Wide distribution range across Europe and east and south Africa and the Middle East.

Remarks. Galba truncatula is considered as the main intermediate host for several species of the genus Fasciola. It is mostly found in irrigation canals and swamps. It has the tendency to adhere to muddy edges of rivers and springs (Amr et al. 2014).

Family Physidae Fitzinger, 1833

Physella acuta (Draparnaud, 1805)

Fig. 14

Materials examined:

Distribution. This is a widespread species in northern America, Europe, Eurasia, and Africa.

Remarks. Physella acuta is one of the most common species found in steady water bodies in the West Bank including temporary irrigation ponds with plastic cover and swamps.

Family Planorbidae Rafinesque, 1815

Bulinus truncatus (Audouin, 1827)

Figs 15–16

Materials examined:

Distribution. Africa, southwest Asia and Portugal, Sardinia and Corsica.

Remarks. This species was reported in Palestine (Abdel Azim & Gismann1956, Saliternik & Witenberg 1959). The snails were found in three sites in three different districts. It prefers still waters such as reservoirs, ponds, slow running waters, and irrigation canals. In the Middle East and Africa, this species acts as intermediate hosts for Schistosoma haematobium (Brown 1994).

Planorbella duryi (Wetherby, 1879)

Fig. 17

Materials examined:

Distribution. This species is endemic to Florida, USA, and now introduced to several countries through aquatic plants used in aquaria.

Remarks. Planorbella duryi is an invasive species which was introduced to our area (Roll et al. 2009). This species was found at the Palestine Museum of Natural History pond, that may have been imported along with an aquatic plant from Jerusalem botanical garden to the museum in Bethlehem.

DISCUSSION

In an earlier study, Handal et al. (2015) reported 10 species of freshwater snails from the West Bank. We added four additional species: Bulinus truncatus, Melanopsis cerithiopsis, Planorbella duryi, and Heleobia sp. The status of Theodoxus jordani and Theodoxus macri is clarified based on recent revisions (Sands et al. 2020); all previous records of T. macri are now considered as T. jordani.

Most species recorded are considered endemic to the Levant, including all species of the genus Melanopsis, T. jordani and E. contempta, while the species B. truncatus, G. truncatula, P. acuta, R. natalensis and M. tuberculata have a wide distribution. A total of at least 33 species of freshwater snails were reported from historic Palestine (Milstein et al. 2012), while 22 species were reported from the Jordan River (Amr et al. 2014).

Nineteen species of invasive freshwater snails were reported as introduced species to Palestine (Roll et al. 2009). Mieniplotia scabra, an invasive species that became well established in Lake Tiberias, caused almost the eradication of four native species (Heller et al. 2014). It is now common in waterbodies in the Jordan Valley within the Jordanian territories (Nasarat et al. 2014). Planorbella duryi was also introduced and is expanding its range within the historic Palestine as well as the West Bank (Roll et al. 2009, Milstein et al. 2012). Although not reported in the current study, Pyrgophorus sp., which is another invasive species, was reported from several localities near the Jordan Valley (Milstein et al. 2012).