Radoman (1973) described this genus with its type species D. graeca Radoman, 1973, from the Daphne Spring in the valley of Tembe, North of Larissa. Schütt (1980) considered D. graeca a junior synonym of Valvata exigua Schmidt, 1856, described from “Greece”. Schütt (1980) designated a neotype from a group of small springs at Agia Paraskevi railway station, situated closely to the Daphne Spring, also in the valley of Tembe in Thessalia, but certainly not close to Thessaloniki as Kabat and Hershler (1993) state. Falniowski and Szarowska (2000) described Daphniola louisi from a small spring at the monastery at Kessariani, Athens, Attica. The description was not considered by Bodon et al. (2001), who followed either Schütt (1980) in synonymizing D. graeca with D. exigua, or Reischütz and Sattmann (1993) in including Valvata (Cincinna) hellenica Westerlund, 1898 in Daphniola exigua, thus rendering the genus Daphniola monotypic. Falniowski et al. (2007), applying soft-part morphology and anatomy as well as molecular markers, demonstrated the species distinctness of D. louisi, and identity of D. exigua with D. graeca. Gittenberger (1982) described Horatia hadei, a new species of Horatia he found 5 km SW of Yíthion (Gythion), southern Peloponnese. Later, Falniowski and Szarowska (2011a) collected this gastropod close to the (probably) destroyed type locality, and both, morphology and molecular data confirmed its classification within the genus Daphniola. Radea (2011) described D. eptalophos Radea, 2011 from the Parnassos Mountains. However, considering morphology, it is certainly not Daphniola especially in the intensively pigmented and massive penis. Its type locality is close (or rather the same) to the type locality of Graecoarganiella parnassiana Falniowski & Szarowska, 2011. Thus “Daphniola etalophos” is most probably a synonym of Graecoarganiella parnassiana, and clearly belongs to Graecoarganiella rather than Daphniola. Szarowska et al. (2014) found a few juvenile specimens (used for DNA sequencing) of Daphniola sp. on each of the two Aegean islands: Rhodos and Khios. Falniowski and Sarbu (2015) described D. magdalenae Falniowski, 2015 from the sulphide Melissotripa Cave in Thessalia. Finally, Radea et al. (2021) described D. dione Radea, Lampri, Bakolitsas & Parmakelis, 2021 from the Levkas Island (Ionian Sea), using morphology and molecular data. At two localities in North Peloponnese (1 and 2) we found another Daphniola taxon, whose morphology and COI sequences do not comply with any known Daphniola species.

Ethanol-fixed specimens, Panagitsa, large spring, Arcadia, Peloponnese, Greece, 37°46'21"N, 22°13'19"E (Fig. 2), altitude 500 m, sieved from sand at the spring head; 26.09.2009; Z.P. Eröss, Z. Fehér, T. Fehér, J. Grego and A. Hunyadi coll., holotype: ZMUJ-M.2137; paratypes: ZMUJ-M.2138-ZMUJ-M.2139, two paratypes; HNHM-105279, 10 wet and 25 dry paratypes, GNHM 39591, 10 paratypes, ZPE 25 dry paratypes, JG F1198, 11 wet and 72 dry paratypes.

Figure 2. 

Type locality of Daphniola longipenia sp. nov. Panagitsa, Arcadia, Peloponnese A spring reservoir B spring head.

MZ093460–MZ093464; MZ265368–MZ265372

Shell minute, valvatiform-trochiform, soft parts slightly pigmented, penis with extremely long and slender filament and small non-glandular outgrowth (lobe) on the left side. Readily distinguished from D. exigua, D. louisi, D. magdalenae and D. dione by the proportionally much lower spire of the shell, and the penis with a narrower base and a longer and thinner filament. Differentiated from the geographically (but not molecularly) most close D. hadei by the shell with usually lower spire, and the penis with smaller outgrowth and still longer and thinner filament.

Shell (Fig. 3A–E) valvatiform-trochiform, up to 1.00 mm tall, having 3.5 whorls, spire height 10–12% height of shell. Apex flat. Teleoconch whorls moderately convex, evenly rounded, growing rapidly in diameter. Aperture slightly elliptical, parietal lip complete, umbilicus very broad, outer lip simple, orthocline. Teleoconch with delicate growth lines, periostracum pinkish or yellowish. Shell parameters for holotype and a series of paratypes are given in Table 3. Inner and outer sides of operculum smooth. Operculum pinkish. Animal brownish, with some spots of black pigment.

Figure 3. 

Shells of gastropods: D. longipenia A–D locality 2 (holotype, 2A32, 2B26, 2B27) E locality 1 (2A29); Daphniola hadei F locality 3 (2A27) G locality 4 (2B19) H locality 5 (2B20) I D. louisi, locality 6 (2A33) J–K Graecoarganiella parnassiana, locality 7 (2A28, 2B23) L–O Isimerope L locality 8 (2A30) M locality 9 (2A31) N locality 10 (2B21) O locality 11 (2A22) P cf. Islamia sp., locality 12 (2A34). Scale bar: 1 mm.

Female reproductive organs (Fig. 4) with a broad loop of the oviduct, a big bursa copulatrix with a long duct, and two moderately small receptacula seminis. Penis (Fig. 5) extremely long and narrow, simple, with an almost vestigial outgrowth proximally on its left edge, and a prominent sharp-terminated filament, vas deferens not visible inside.

Figure 4. 

Pallial and renal section of female reproductive organs of Daphniola longipenia [bc – bursa copulatrix, cbc – duct of bursa, ga – albuminoid gland, gn – nidamental gland, gp – gonoporus, ov – oviduct, ovl – loop of (renal) oviduct, rs – seminal receptacles (in black) rs₁ and rs₂ (as defined by Radoman 1973, 1983): rs₁ – distal, rs₂ – proximal]. Scale bar: 250 μm.

Figure 5. 

Penis of Daphniola longipenia, bar equals 200 μm.

The specific epithet longipenia refers to the extremely long filament of the penis.

Apart from the type locality (our locality 2), this species was also found in the spring at the W edge of Katarraktis, Achaia, Peloponnese (our locality 1).

Westerlund (1898) described Valvata (Cincinna) hellenica Westerlund, 1898, from “Vyteria in Arkadien”. Reischütz and Reischütz (2004) identified Westerlund’s “Vyteria” as Vitina, situated about 15 km from Panagitsa. They reported Hauffenia hellenica (Westerlund, 1898) also from Panagitsa spring. Our D. longipenia is most probably the gastropod reported by them. However, their identification of “Vyteria” as Vitina remains doubtful. The shell of the lectotype of Valvata hellenica presented by Reischütz and Sattmann (1993) looks different (Fig. 6) (enormously high and massive body whorl, another size and outline of the aperture). Valvata hellenica was reported several times from localities scattered throughout Greece, often in generic combination with Hauffenia or Daphniola. It can be assumed that these records report more than one species; or it was mentioned as a younger synonym under Daphniola exigua (e.g., Bodon et al. 2001). Summarising, the description of a new species is the most appropriate solution.

Figure 6. 

A shell of lectotype of Valvata hellenica presented by Reischütz and Sattmann (1993) B shell measurements: a – shell height, b – body whorl breadth, c – aperture height, d – spire height, e – aperture breadth, α – apex angle.

In our trees (Figs 7, 8), D. longipenia is clearly distinct from all the other species of Daphniola and forms a distinct sister clade opposite to the remaining currently known Daphniola species. The high genetic distance (p-distance 0.106) can be found between D. longipenia and D. hadei (p-distance 0.106), whose localities are most close, and who share the most similar shell morphology, female reproductive organs and penis). In general, the genetic distances between D. longipenia and the other Daphniola varies from 0.097 (for D. exigua) to 0.141 (for D. magdalenae) (Table 4).

Figure 7. 

Phylogenetic tree for COI showing relationships between the studied snails. Bootstrap supports (>60%) and Bayesian probabilities are given.

Figure 8. 

Phylogenetic tree inferred from connected COI and H3 sequences. Bootstrap supports (>60%) and Bayesian probabilities are given.

MZ093457–MZ093459; MZ265365–MZ265367

At the localities 3, 4 and 5 (Fig. 1, Table 1) gastropods were collected, whose shells (Fig. 3F–H), soft parts morphology and anatomy, clearly identified them as belonging to this species. Their molecular data (Figs 7, 8) were identical or nearly identical with the ones published in the GenBank. Their localities are situated somewhat north of the type locality.

MZ093456, MZ265364

The shell morphology (Fig. 3I), soft-part anatomy and molecular data (Figs 7, 8) of the gastropods collected at locality 6 (Fig. 1, Table 1), all showed that they belonged to this species. It has to be noted that the molecular variability in this species (p-distance 0.044) (Fig. 7) is much larger than in D. hadei (p-distance 0.013). The new record of D. louisi, located on Evvoia Island, considerably expands the range of the species, which so far was only known from Attica. The close phylogenetic relationship with the two juvenile Daphniola specimens collected on the Aegean islands, Rhodos and Khios, now combined with the present record from Evvoia, seems to confirm the ideas about the means of dispersal of Daphniola from continental Greece to the Aegean islands (Szarowska et al. 2014).

MZ093454–MZ093455; MZ265362–MZ265363

Falniowski and Szarowska (2011b) described a new, so far monotypic, genus of Hydrobiidae from Greece, Parnassus Mountains, S of Eptalofos, N of Kalania, found in a cistern and a small spring in a grassy pasture on a mountain pass. The type species, G. parnassiana Falniowski & Szarowska, 2011, is so far known only from the type locality. At the locality 7 (Fig. 1, Table 1), mouth of Erkinas Gorge, Kria 2, Boeotia, Livadia, we found gastropods, whose shells (Fig. 3J–K), and soft-part morphology indicated they belonged to Graecoarganiella, and were practically identical to G. parnassiana. Anatomy was not studied since the material was scarce and not fixed well enough. Our locality 7 is not far (about 35 km) from the type locality of G. parnassiana. The molecular data – partial sequences of COI – of our population showed rather high distinctness (Fig. 7). However, as can be seen in the same phylogram, these differences (p-distance 0.038) are a little lower than the ones within Daphniola louisi (0.044). Thus, inclusion of our new population in Graecoarganiella parnassiana is seemingly justified.

MZ093450–MZ093453; MZ265358–MZ265361

When describing Graecoarganiella parnassiana from the Parnassus Mts., Falniowski and Szarowska (2011b) reported three young hydrobiid specimens found at Mainalo Mountain, Peloponnese, WSW of Piana, WNW of Tripolis, in a medium-sized spring and cistern. Their COI sequence was interpreted as indicating a distinct species congeneric with Graecoarganiella parnassiana. Later, Radea et al. (2013) found other species at Megali Vrisi, Pharmakas Mt., and described it as a representative of a new monotypic genus Isimerope, with I. semele as the type species. In our tree (Fig. 7) Graecoarganiella and Isimerope are quite distinct (p-distance 0.096), but form a well-supported clade (bootstrap value of 100%, Bayesian probability 1.0). The shells are very similar, and the same holds true for the radulae. The lack of a ctenidium, and egg capsules laid in the umbilicus of the shell, might be considered as unique shared character states. The penes and female reproductive organs of the compared taxa do not differ more than could be expected by different season of collection or fixation technique.

At the four localities: 8, 9, 10 and 11 (Fig. 1, Table 1) we collected gastropods, whose shells (Fig. 3L–O), soft parts morphology (not well-fixed material reduced the possible examination) and molecular data (Fig. 7) showed them as belonging to Isimerope. Again, as in the case of Graecoarganiella, our specimens of Isimerope may represent distinct species, but as in Daphniola, the molecular differences may be considered as within- species level variation (p-distance 0.035).

Our molecular data clearly show the close relationship of Isimerope and Graecoarganiella, contradicting their classification to different subfamilies (Belgrandiinae de Stefani, 1877 and Horatiinae D. W. Taylor, 1966, respectively), as stated in WORMS (WoRMS Editorial Board 2021). Both more anatomical and molecular data, as well as a broad-scale revision of the systematics of the Truncatelloidea proposed by Bouchet et al. (2017) are badly needed.

MZ093465; MZ265373

At the locality 12, in Mili, Argolis, in a spring below the power station, a gastropod was found (Fig. 3P), whose molecularly inferred phylogenetic position (Fig. 8) remains enigmatic. Its sister taxon is Islamia Radoman, 1973. The clade’s bootstrap support for two concatenated loci is 100%, strongly suggesting that both mOTUs belong to the same taxon, but the genetic distance between them seems too high (p-distance 0.135). The p-distances in COI were 0.109 and 0.138 between this taxon and Fissuria Boeters, 1981 and Alzoniella Giusti & Bodon, 1984, respectively, although the shell morphology still suggests an affiliation with Islamia. Anyway, with only one more shell and lack of molecular data on the other Greek Islamia species, a justified taxonomic decision has to be postponed until more, and better, preserved specimens are available.