Theodoxus and Neritina are distinguished from each other by their ontogeny (Bandel 2001). While the Theodoxus species hatch from the spawn as miniature adult, Nertina species leave their spawn as planktotrophic larva that will float in the sea for a more or less extended period before its metamorphosis to a crawling young. However, at the adult stage the taxonomic separation of species of the genera Theodoxusand Neritinais not always easy. As most of the Neritina spp. are marine species and usually have a denticulate border of the columella and two apophysis of the operculum, most species of the genus Theodoxus are limnic and have a smooth border of the columella and one apophysis (the “rib”); some also have a small apophysis, the peg, on the operculum (Glöer 2002). Further, in Neritina the peg is thick and strong, while in Theodoxus it is, if exists at all, small and weak. A revision of this family, particularly its subdivion in clearly defined genera is needed.

Khuzestan Province (Mansoorian 2001).

Zoological Museum Berlin (ZMB), “Neritina (Neritaea) anatolica var. mesopotamica, Ras el Ain, Mesopot. Hausknecht”.

The height of the largest shell of the examined syntypes from Zoological Museum Berlin was 7 mm. Mansoorian (1994) in his identification key described shell of this species as being 14 mm high. Considering his photos (Mansoorian 1994), he probably confused it with Neritina schlaeflii Mousson, 1874 (Figs 2f–g).

Iraq, Iran (Khuzestan).

Khuzestan Province (Chu et al. 1968, Massoud and Hedayeti-Far 1979).

Remark. According to the original description (Martens 1874) this species is characterized by the presence of denticulated border of the columella, and should be ascertained to the genus Neritina.

Iraq, Iran.

Khuzestan Province (Massoud and Hedayeti-Far 1979, Mansoorian 2001).

This speciesis characterized by a small shell with 6 mm in height and a small spire. The boder of the columella is straight and not denticulated. The operculum has a rib which is attenuated at its basis, the peg is thick and strong and split in two parts (fig. 2e).

Iraq, Iran.

Fars Province: IR13-07 [3 ex.]; IR14-07 [2 ex.]; Khorrasan Province: IR76-05 [1 ex]; IR 64-05 [1 ex.]; IR78a-05 [2 ex.]; IR79-05 [1 ex.]; Hormozgan Province: IR 17-11 [5 ex.]

Melanopsis sp., Radix sp., Planorbis intermixtus, Farsithyra farsensis, Physella acuta.

Martens (1879) synonymised Theodoxus doriae, the species reported by Issel (1863) from S Iran, with Theodoxus fluviatilis. Later on, Mansoorian (2000) described the operculum of Theodoxus doriae, which has only a rib, no peg. However, the shell illustrated by Mansoorian (1994) agrees well with Theodoxus fluviatilis. Thus we follow Martens’ (1879) synonymisation of Theodoxus doriae with Theodoxus fluviatilis. Our samples revealed onlythe presence of Theodoxus fluviatilis.

W- to Central-Palaearctic. Theodoxus fluviatilis has been considered by many authors to be an exclusively European species (see e.g. Zhadin 1952, Glöer 2002). But Bourguignat (1864), Brown (1994) and Van Damme (1984) mentioned it from NW Africa (Morocco, Algeria). Records of this species in Turkey (Yıldırım 1994), and in Iran, confirm its wide distribution. However, it does not occur in Siberia (Vinarski, pers. comm.).

Kerman Province (Biggs 1971); Mazandaran Province (Eichwald 1838, Eliazian et al. 1979).

This species has been described from the Caspian Sea. According to the original description (Eichwald 1838) this species is very distinct from the other Theodoxus spp. mentioned here.

Iran.

Isfahan and Fars Province (Starmühlner and Edlauer 1957).

NHMW 75000/E/50824, “Theodoxus pallidus Dunker” Persien, Brackiger Quellsee, 500 m, nördl. vom Niris-see, leg. Starmühlner 1949.

Starmühlner and Edlauer (1957) provide a detailed description of the anatomy of this species but did not consider the operculum, the most important diagnostic feature. On the other hand, as figured in Starmühlner and Edlauer (1957), the receptaculum seminis and the bursa copulatrix differ in length (while being of equal length in Theodoxus fluviatilis).

The re-examination of the specimens of Theodoxus pallida (Dunker, 1862) from Edlauer’s collection in NHMW clearly shows that this species is distinct from Theodoxus fluviatilis due to the shape of shell and the operculum (Fig. 3). As already mentioned by Dunker (1862) the spire in Theodoxus pallida is higher than in Theodoxus fluviatilis, and furthermore the apophysis of the operculum is broader and not attenuated at its basis (Fig. 3c). In addition the callus at border of the operculum in Theodoxus pallida is much stronger (Fig. 3c arrow).

Iran.

Khuzestan Province (Chu et al. 1968, Massoud and Hedayeti-Far 1979, Mansoorian 1994, 2001), Mazandaran Province (Mansoorian 2000).

According to Ramakrishna and Dey (2007) this species is widely distributed on the Indian subcontinent.

Seistan and Baluchestan Province (Annandale et al. 1919).

Iran.

Buccinum praemorsum Linnaeus, 1758

Melanopsis praerosa L. is a misspelling of Melanopsis praemorsa L.

Kerman Province(Martens 1874); Khuzestan Province (Prashad 1921, Chu et al. 1968, as Melanopsis nodosa: Massoud and Hedayeti-Far 1979, Mansoorian 2001).

Fars Province: IR13-07 [23 ad., 25 juv.].

Farsithyra farsensis.

Asia Minor, Syria, Palestine, Iraq, Iran.

Kerman Province (Issel 1863, Martens 1874, Biggs 1936, 1937, Starmühlner and Edlauer 1957, 1961, 1965); Fars Province (Starmühlner and Edlauer 1957); Yazd Province (Starmühlner and Edlauer 1957); Khuzestan Province (Mansoorian 1994, 2001); Mazandaran Province (Starmühlner and Edlauer 1957, Mansoorian 2000); Gilan Province (Starmühlner and Edlauer 1957); Bushehr Province (Starmühlner and Edlauer 1957).

Hormozgan Province: IR17-11 [2 ex.]; IR19-11 [1 ex.].

NHMW “Melanopsis doriae Issel” Persien, Kerman, aus teilweise eingestürztem Kanal, leg. Starmühlner 1949/50.

Melanoides tuberculatus, Thiara scabra, Farsithyra farsensis.

Starmühlner and Edlauer (1957) studied the anatomy of Melanopsis doriae and Melanopsis kotschyi showing differences in the nervous system. Furthermore they found differences in some features of the opercula between these species, and showed a strong morphological plasticity of the shells (see: Starmühlner and Edlauer 1957, plate 1: Figs g’, g’’, g’’’ and h’, h’’). Re-examintion of Melanopsis doriae from Edlauer’s collection in NHMW shows that the shell (Fig. 4) is slimmer than the shell of Melanopsis sp.

Iran.

Fars Province (Starmühlner and Edlauer 1957).

Seeremarks under previous species.

Iran.

Kerman Province (as Melanopsis variabilis:Martens 1874); Seistan and Baluchistan Province (as Melanopsis deserticola: Annandale and Prashad 1919); Isfahan and Yazd provinces (Biggs 1937); Fars province (as Melanopsis buccinoidea variabilis:Starmühlner and Edlauer 1957, as Melanopsis praerosa:Starmühlner 1961); Khuzestan Province (Chu et al. 1968, as Melanopsis praerosa:Massoud and Hedayeti-Far 1979, Manssorian 2001).

Mazandaran Province: IR02-05 [11 ad., 48 juv.]; Khorrasan Province: IR64-05 [12 ad., 39 juv.]; IR79-05 [3 ad., 4 juv.]; IR78a-05 [8 ad., 15 juv.]; IR78c-05 [2 ex.]; Fars Province: IR17-07 [2 ex]; Hormozgan Province: IR19-11 [21 ex.].

Galba truncatula, Theodoxus fluviatilis, Planorbis intermixtus, Grossuana sp., Farsithyra farsensis.

The species of this genus have a high morphological plasticity and many species have been described. Glaubrecht (1993) tried to solve the complicated taxonomy by proposing to consider all circum-Mediterranean Melanopsis spp. as being part of one ‘superspecies’, Melanopsis praemorsa. However, we follow Neubert (1998) who believes that this approach does not solve the problem. In recent literature the ‘superspecies’ notion tends to be abandoned and the former species names are being reinstituted (see: Heller et al. 2005; Van Damme et al. 2010. This means that the smooth unsculptured species Melanopsis praemorsa sensu stricto (terra typica: Spain) is actually a western Mediterranean species and that unsculptured morphs from the Levant belong to other species, such as Melanopsis buccinoidea, Melanopsis ammonis, Melanopsis dircaena, Melanopsis khabourensis and Melanopsis meiostoma (Heller et al. 2005). Those from Mesopotamia have been described under Melanopsis variabilis, Melanopsis deserticola, Melanopsis buccinoidea and Melanopsis praemorsa. Further study is necessary to establish under which name or names the Iranian populations should be placed.

Hormozgan Province (Ghasemi et al. 2011).

Hormozgan Province:IR14-11 [21 ad., 6 juv.]; IR-20-11 [10 ex.].

Ecrobia grimmi, Pseudamnicola sp.

Indo-Pacific coast.

Seistan and Baluchestan Province (as Melanoides scabra var. elegans: Annandale and Prashad 1919); Isfahan Province (as Melanoides scabra: Biggs (1937); Hormozgan Province (Starmühlner and Edlauer 1957).

Hormozgan Province: IR08-11 [13 ex.]; IR17-11 [2 ex.].

Farsithyra farsensis, Melanoides tuberculatus, Physella acuta, Melanopsis doriae.

Indo-Pacific coasts.

Seistan and Baluchestan Province: IR8a-11 [5 juv.], IR8-11 [18 ex.]. Hormozgan Province: IR10-11 [3 ex.], IR17-11 [10 ad., 9 juv.], IR18-11 [1 ad., 8 juv.], IR19-11 [2 ex.].

Melanopsis doriae, Thiara scabra, Farsithyra farsensis.

Kerman Province (as Melania tuberculata: Issel 1863), Martens 1874, Biggs 1936, 1937, Starmühlner and Edlauer 1957); Seistan and Baluchestan Province (as Melanoides pyramis, Melanoides tigrina: Annandale and Prashad 1919, Biggs 1937); Hormozgan Province (Biggs 1937, Starmühlner and Edlauer 1957), (as Melania tuberculata: Starmühlner (1961); Isfahan Province (Biggs 1937); Yazd Province (Starmühlner and Edlauer 1957, as Melania tuberculata: Starmühlner 1965); Khuzestan Province (Chu et al. 1968, Mansoorian 2001); South Iran (Manssorian 1994); Fars Province (Starmühlner and Edlauer 1957): Mazandran Province (Starmühlner and Edlauer 1957, Mansoorian 2001).

The species Melanoides pyramis and Melanoides tigrina, which have been mentioned by Annandale and Prashad (1911) from Seistan and Baluchistan, have been listed by Westerlund (1886) as subspecies. However, due to the high morphological plasticity of Melanoides tuberculatus and in absence of any geographical seperation of these taxa, we list all Melanoides taxa under Melanoides tuberculatus.

S Asia, Arabia, Near East, Africa.

Mazandaran Province (Mansoorian 2000); Gilan and Lorestan Province (Mansoorian 2000).

Mazandaran Province (Forcart 1935).

The Euro-Siberian species Bithynia tentaculata (Linnaeus 1758) has often been mentioned from Iran, Turkey and Greece. However, this species could not be found in Greece (Glöer et al. 2010) and probably does not occur in Turkey. The southern distribution border of this species lies possibly in N Bulgaria (Georgiev pers. comm.). An analysis of the specimens from NMB published by Forcart (1935) as Bithynia tentaculata shows that these specimens represent Bithynia forcarti sp. n. (see below). Thus, Bithynia tentaculata most probably does not occur in Iran and has been confused with Bithynia forcarti sp. n. or possibly with Bithynia mazandaranensis sp. n. (see below).

Euro-Siberian.

Mazandaran Province, Tschalekuti.

(NMB 11517a): shell height 7.5 mm, width 5.6 mm.

Mazandaran Province, Tschalekuti (NMB 11517a, 26 ex.), Geniste d. Babul (NMB 11517b, 1 ex., NMB 11571c, 10 ex.)

Named after Lothar Forcart in appreciation on his studies of Iranian freshwater snails.

The whitish shell is conical with 5.5 whorls, which are convex with a deep suture and a small and acute apex. The convex whorls are flattened at the suture. The umbilicus is open. The aperture is ovate, angled at the top. The margin of the aperture is, from lateral view, slightly sinuated. The surface is smooth with fine growth lines. Shell height 5.5 – 7.5 mm, width 5.0 – 5.6 mm.

Due to theshape of the aperture (angled at the top), Bithynia forcarti sp. n. resembles Bithynia mazandaranensis sp. n. (see below). However, from the latter species it can be easily distinguished by the stepped whorls.

Formerly (Forcart 1935) this species has been confused with Bithynia tentaculata.

Border of Lake Urmia, W Azarbayian, 1949 leg. Starmühlner.

NHMW (50940): shell height 10.3 mm, width 5.6 mm.

9 ex. from the type locality.

Named after Ferdinand Starmühlner, who collected this species in 1949.

The whitish shell is elongated conical with 6.5 whorls, which are convex with a deep suture and a small and acute apex. The umbilicus is open. The aperture is ovate. The margin of the aperture is, from lateral view, straight. The surface is smooth with fine growth lines. Shell height 8.2 – 10.3 mm, width 4.6 – 6.4 mm.

This slim species isthe largest Bithynia sp. known in Iran. It can be easily distinguished from the other Bithynia spp. by the larger dimensions of elongated shell with the stepped whorls and the not angled aperture.

This species has been misidentified by Starmühlner and Edlauer (1957) with Bithynia troschelii.

Mazandaran Province, Nowshahr city, pond near Caspian Sea, 51°31'E, 36°38'N, 18 June 2005.

(ZMH 79369):Shell height 8.0 mm, width 5.0 mm.

Named after the region where the species was collected.

The horn-coloured shell is conical with 5.5 whorls, which are slightly convex with a clear suture and an acute apex. The umbilicus is closed. The aperture is ovate, angled at the top. The margin of the aperture is, from lateral view, sinuated. The surface bears a lattice structure. Shell height 8.0 mm, width 5.0 mm, aperture height 3.6 mm.

The new species resembles Bithynia tentaculata but differs from it by the following features: (i) the operculum is more angled (Fig. 7c), (ii) the whorls are more convex (Fig. 7a–b), and (iii) the surface has longitudinal and transverse striae (Fig. 7d).

Planorbis carinatus, Anisus sp., Valvata cristata, Valvata nowshahrensis sp. n., Hippeutis complanatus.

Probably this species formerly (e.g., Mansoorian 2000) was confused with Bithynia tentaculata. Because we had only an empty shell of this species, we do not know if it belongs to the genus Bithynia or Pseudobithynia, so our generic assignment is tentative. To address this question, anatomical studies of more specimens are necessary.

Isfahan Province – (as Amnicola ejecta: Biggs 1937).

Probably due to the small size of this species, Biggs (1937) assigned this species belongs to the genus Amnicola, although Mousson (1874) described it as a Bythynia, and pointed out that the operculum is characteristic for Bythinia and different from Amnicola (syn. to Pseudamnicola). Furthermore, Biggs (1937) found his species in the mountains, while the original description of Bithynia ejecta comes from the lowland, indicating the Biggs’s species is not conspecific with Bithynia ejecta and probably represents an undescribed species.

North Iran (Caspian Sea) – Eliazian et al. (1979).

This species could not be found in any of the neighbouring countries of Iran. Eliazian et al. (1979) don’t mention the source that led to their identification. The record and taxonomic status of this species is questionable and needs new confirmation.

Some authors (e.g Subba Rao 1989, Nesemann et al. 2007) mention Gabbia as a genus. However, it seems not possible to distinguish the genera of the Bithyniidae by the shape of opercula (Mandahl-Barth 1968) and/or by shell forms, because these characters are found to be variable. On the other hand, the examined material of the family of Bithyniidae can be easily separated by the characteristics of penis morphology (having a penial appendix: Bithynia Leach 1818; or lacking a penial appendix: Pseudobithynia Glöer & Pešić 2006). In our study, we tentatively use the name Gabbia as a subgenus for small Bithynia species with a globular shell, originating from India.

Seistan and Baluchestan Province (as Amnicola sistanica: Annandale and Prashad 1919).

Annadale and Prashad (1919) described this species as Amnicola (Alocinma) sistanica and depicted the penis morphology. Due to the presence of a penial appendix this species is ascertained to the genus Bithynia. The members of the genus Pseudamnicola (formerly Amnicola) have no penial appendix.

Iran; only known from N Seistan.

Markazi and Lorestan Provinces (Glöer and Pešić 2006).

Lorestan Province:IR26-07 [10 ex.].

Planorbis intermixtus, Radix sp.

Iran; Markazi and Lorestan Provinces.

Fars Province (Glöer and Pešić 2009).

Iran; known only from the locus typicus (Dasht Arzhan village, Shiraz to Kazerum road).

Hormozgan Province:IR14-11 [12 ad., 20 juv.].

Cerithidea cingulata,, Ecrobia grimmi, Pseudamnicola sp.

New for Iran.

Previously only known from the brackish part of rivers along the coast of Croatia (Radoman 1983).

Isfahan Province (Biggs 1971).

Fars Province (Starmühlner and Edlauer 1957).

Probably this species has been confused with one of the following species (Ecrobia grimmi, Heleobia dalmatica), so all former records of this species in Iran are questionable. The record for this species is kept until the original material of Biggs could be studied.

Hormozgan Province:IR14-11 [12 ad., 20 juv.].

Cerithidea cingulata, Heleobia dalmatica, Pseudamnicola sp.

On the base of molecular results, Haase et al. (2010) concluded that Ecrobia grimmi from the mixomesohaline Lake Sawa (Iraq) was possibly transported by migrating birds from the Caspian Sea. The identification of our material of Ecrobia grimmi as well of Heleobia dalmatica was confirmed by using molecular techniques (Martin Haase pers. communication). An analysis of the specimens from NHMW published by Starmühlner and Edlauer (1957) as Hydrobia acuta shows that these specimens probably belong to Ecrobia grimmi (see Fig. 8c).

Caspian Sea; Iraq, Iran.

Tehran Province – “Frauenfeldia elburensis” Starmühlner and Edlauer (1957).

Starmühlner and Edlauer (1957) originally described this species as Frauenfeldia elburensis. However, the genus name Frauenfeldia is preoccupied, and thus, the species of this genus have been re-assigned to Belgrandiella, Boleana, Graziana and Sarajana (Radoman 1983). Due to the shape of the aperture in original description (see Starmühlner and Edlauer 1957) we affiliate this species to the genus Belgrandiella.