Theodoxus gurur Sands & Gloeer, 2020

Sands, Arthur F, Gloeer, Peter, Guerlek, Mustafa E, Albrecht, Christian & Neubauer, Thomas A, 2020, A revision of the extant species of Theodoxus (Gastropoda, Neritidae) in Asia, with the description of three new species, Zoosystematics and Evolution 96 (1), pp. 25-66 : 25

Theodoxus gurur Sands & Gloeer sp. nov. Figures 12A, B , 13A-G , 14A-F

Type locality.

Suyunbaşı spring complex, Ayrancılar, İzmir, Turkey; 38.24826°N, 27.28117°E (Figs 3A , 12A, B ).

Holotype.

RMNH. MOL.342197 ( Suyunbaşı spring complex, Ayrancılar, İzmir, Turkey; 38.24826°N, 27.28117°E) stored in NMNL: Shell height 5.8 mm, width 6.0 mm (Fig. 13A-D ) .

Paratypes.

Twenty four specimens from Suyunbaşı spring complex, Ayrancılar, İzmir, Turkey; 38.24826°N, 27.28117°E: 11 in NMNL ( RMNH. MOL.342198, RMNH. MOL.342199; Fig. 13E-G ) and 13 in UGSB ( UGSB 20689, UGSB 20745, UGSB 20746; Fig. 14A-F ) .

Etymology.

The word " gurur " means “pride” in Turkish, referring to the PRIDE (Drivers of Pontocaspian Biodiversity Rise and Demise) programme (also see Acknowledgements). One of its aspects is understanding the evolution of mollusc species in the Pontocaspian and associated satellite regions in Anatolia and the Balkans.

Description.

Shell (Fig. 13A-C, E-G ): Hemispherical, transversely slightly elongate, consisting of typically 3-3.5 whorls that rapidly grow. Spire of low to moderate height for Theodoxus ; apex often corroded. Shell height ranges from 5-6.5 mm, width from 5.3-7.0 mm. Periostracum uniformly black; surface can be glossy, always finely striated with growth lines. Aperture semicircular; no serrations on the inner lip. Columellar plate smooth, flat to slightly concave, inclined towards aperture; blue-grey in colour.

Operculum (Fig. 13D ): Operculum plate made of two parts, calcareous base and conchioline lamella; calcareous base mostly light to dark brown; lamella light yellow-orange. Left adductor of operculum base slightly triangulate, no obvious callus on top right edge. Apophysis distinctively white; broader at top, narrower and attenuated at bottom. Rib-shield strong. Small, short rib-pouch. Small white pseudo-apophysis extends from base of apophysis.

Radula (Fig. 14A-F ): R-central tooth flanked by the A-central, B-central, C-central, E-lateral on each side. Additionally, two interconnected layers of marginal teeth occur, encasing central and lateral teeth. R-central with nearly rectangular face, slightly concave anterior edge. A-central large and flat with thin ridge; some curling of ridge on upper edge of cusp. B-central diminished, forms irregular “S” shape. C-central equally diminished, partly hidden below lower edge of E-lateral. E-lateral simple, with no serration on upper edge. First layer of marginal teeth comprises 35-37 teeth, which decrease in size away from E-lateral but increase in size and show serrations on edges of small faces; semidetached from second layer, which is fused and forms outer wall.

Differentiating features.

Using only conchological features of periostracum colouration and patterning and shell shape, the hemispherical, glossy black, and finely striated shells of T. gurur sp. nov. are easily differentiable from T. altenai , which displays light ivory spots on a dark brown-black background (Figs 4A-G , 13A-G ), and T. gloeri , which lacks shell pigmentation and bears strong axial ribs on the shell (Figs 11A-C , 13A-G ). However, it is still challenging to differentiate T. gurur sp. nov. from some morphotypes of T. anatolicus , T. baeticus , T. fluviatilis , T. jordani , T. macri (G.B. Sowerby II, 1849), T. major Issel, 1865, T. pallidus (Dunker, 1861), T. syriacus (Bourguignat, 1852), T. velox , T. wesselinghi sp. nov., and T. wilkei sp. nov., which can share hemispherical, glossy black, and finely striated shells (Figs 5A-M , 6A-G , 8A-D , 10E-H , 13A-G , 15P-R , 16C-E, O, P , 18A-D , 19O, P , 20A-D , 21I-R , 22I, J , 24H-J , 27A-D ). Theodoxus gurur sp. nov. can be distinguished from Anatolian morphotypes of T. baeticus , which typically displays ivory blotches on brown background (Fig. 7A-D ); T. jordani , which typically displays brown diagonal zig-zag line patterning on an ivory background (Fig. 15E-L ) and T. velox , which tends to have white-ivory stripes on a dark background (Fig. 22K-M ). Moreover, T. jordani typically has a lighter columellar plate in comparison (Figs 13 , 15 - 17 ). Finally, the light to dark brown calcareous base of the operculum in T. gurur sp. nov. can help to distinguish it from T. altenai , T. anatolicus , T. baeticus , T. jordani , T. macri , T. major , T. pallidus , T. syriacus , and T. wesselinghi sp. nov., which typically have lighter calcareous bases ranging from ivory to cream or light brown (Figs 4 - 8 , 13 , 15 - 21 , 24 ); Theodoxus wilkei sp. nov., differs in its bright orange operculum (Figs 13 , 27 ).

More differentiating features occur in the structure of the operculum. These include the attenuated apophysis in T. gurur sp. nov. (Fig. 13 ), which is lacking or reduced in T. altenai and T. jordani (Figs 4 , 15 , 17 ). The lack of or an extremely diminished rib-pouch and rib-shield in T. altenai , T. anatolicus , T. jordani , and T. macri separate these species from T. gurur sp. nov. (Figs 4 , 5 , 13 15, 17, 18). Additionally, the presence of a pseudo-apophysis differentiates T. gurur sp. nov. from T. fluviatilis , T. major , T. pallidus , T. syriacus , T. velox , T. wesselinghi sp. nov., and T. wilkei sp. nov. (Figs 9 , 10 , 13 , 19 - 22 , 24 , 27 ). Theodoxus anatolicus , T. baeticus , T. jordani , and T. macri , in turn, appear to have overall larger pseudo-apophyses (Figs 5 - 8 , 13 , 15 , 17 , 18 ). Finally, the presence of a strongly defined callus on the top edge of the right adductor in T. altenai , T. anatolicus , T. baeticus , T. fluviatilis , T. pallidus , T. syriacus , T. wesselinghi sp. nov., and T. wilkei sp. nov. may help in differentiation from T. gurur sp. nov. (Figs 4 - 10 , 13 , 20 , 21 , 24 , 27 ). Also, the more angulated left adductor of the operculum base of this species differs from the rounded left adductor seen in T. syriacus , T. wesselinghi sp. nov., and T. wilkei sp. nov. (Figs 13 , 27 ).

Little is known about the radula of many recognised Theodoxus spp. Based on the available data, T. gurur sp. nov. can be distinguished by the rectangular face of the R-central from T. fluviatilis , T. jordani , T. wilkei sp. nov., and T. wesselinghi sp. nov., which have more square, triangulate or globular faces in comparison (see Baker 1923; Zettler 2008; Figs 14B , 25B , 28B ). The smooth upper edge of the E-lateral can be used to distinguish T. gurur sp. nov. from T. wilkei sp. nov. and T. major , which generally have large serrations (see Anistratenko et al. 2017; Fig. 14B, C ).

Remarks.

Our results, as well as the phylogeny of Sands et al. (2019a), suggest T. gurur sp. nov. belongs to a large clade of Anatolian and Mediterranean species that includes T. altenai , T. anatolicus , T. baeticus , T. jordani , T. macri , T. marteli , and an undescribed species from Spain ( Sands et al. 2019a; Fig. 2 ). The T. gurur sp. nov. lineage likely diverged from these species during the Pliocene (Fig. 2 ).

Distribution.

Only known from the type locality (Figs 3A , 12A, B ).

Ecology.

The Suyunbaşı spring complex is part of a recreational park that has been heavily altered to channel and pool water for recreational activities (personal observation M.E.G.). The spring floor and channels are made up of a number of small to large stones or coarse sand, while macrophytes are largely absent (Fig. 12A, B ). Theodoxus gurur sp. nov. can be found attached to stones and concrete banking and co-occurs with Pseudamnicola sp. (personal observation M.E.G.).

Figures

Figure 2. Dated phylogeny of the genus Theodoxus constructed with BEAST, based on existing GenBank and newly incorporated data for COI, 16 S and ATPα (Suppl. material 1: Table S 1). Morphospecies where associations are queried are highlighted by a question mark after the species name (see the " Systematic checklist " for more information). Small green (PP ≥ 0.95) and red (PP <0.95) dots on nodes indicate the relative posterior probability support of divergence events. Node labels (1 - 32) correspond to divergence dates and HPD intervals in millions of years ago (Mya) for selected nodes (see Suppl. material 1: Table S 3). Dashed dark blue and light blue lines represent the minimum interspecific and maximum intraspecific variation determined by Sands et al. (2019 a) to aid Theodoxus spp. delimitation (see see Methods, Phylogenetics and species delimitation and that study for more information on the delimitation methods).

Figure 3. Occurrence map for Theodoxus spp. in Asia. All points conform to specimens used in the phylogenetic analyses (Suppl. material 1: Table S 1), except for T. gloeri for which no molecular data are available and only the type and paratype localities are indicated. Species are partitioned across four identical maps (A - D) to limit overlap of points as far as possible. Barring T. gloeri, closer related species are grouped together (Fig. 2).

Figure 4. Theodoxus altenai Schuett, 1965. A - C. Holotype from Lake Kirkgoez, Doesemealti, Antalya, Turkey (RNL V. 56 / 1, NMNL). D - G. Topotype (UGSB 24167) incorporated into the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 5. Theodoxus anatolicus (Recluz, 1841). A - D. Specimen collected at Isikli, Denizli, Turkey (UGSB 24168) incorporated into the phylogeny (Fig. 2); E - G. Lectotype of N. anatolica from Izmir, Turkey (MHNG-MOLL- 15028). H, I. Paralectotype of N. anatolica from Izmir, Turkey (MHNG-MOLL- 15028); J, K. Paralectotype of N. anatolica from Chios, Greece (MNHN-IM- 2000 - 32519); L, M. Syntype of N. belladonna from Izmir, Turkey (ZMZ 528908). Scale bars: 1 mm.

Figure 6. Theodoxus baeticus (Lamarck, 1822). A - C. Paralectotype of N. baetica from Andalusia, Spain (MHNG-MOLL- 51319). D) Operculum of a paralectotype of N. baetica from Andalusia (MHNG-MOLL- 51319); E - G. Lectotype of N. baetica from Andalusia (MHNG-MOLL- 51319); H-J; K; L; M; N. Five syntypes of N. meridionalis from Sicily (ZMB, without coll. no.); O - R. Topotype of N. guadianensis collected in the Guadiana River near Mertola, Portugal incorporated into the phylogeny (UGSB 22084); S - V. Specimen from Soller, Balearic Islands used in the phylogeny (UGSB 19162). Scale bars: 1 mm.

Figure 7. Theodoxus baeticus (Lamarck, 1822). A - D. Specimen (T. callosus - morphoype) collected in Akyaka, Turkey (UGSB 19118); E - H. Specimen (T. callosus - morphotype) collected in Kato Tragana, Greece (UGSB 2488); I - L. Specimen (T. varius - morphotype) collected at the Blue Eye Nature Monument, Albania (UGSB 24170); M - P. Specimen (T. meridionalis - morphotype) collected at the Ketana Oasis, Gabes, Tunisia (UGSB 18111). All specimens, except A-H, were used in the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 8. Theodoxus baeticus (Lamarck, 1822). A - D. Specimen from Cuquillo, Granada, Andalusia, Spain (UGSB 22089); E - H. Specimen (T. meridionalis - morphotype) collected in the Palancia River, Navajas, Spain (UGSB 22090); I - L. Specimen (T. elongatulus - morphotype) from Arrancada, Pombal, Portugal (UGSB 22080); M - P. Specimen (T. velascoi - morphotype) from Montanejos, Castellon, Spain (UGSB 22082). Theodoxus cf. valentinus (Graells, 1846). Q - S. Specimen conforming to T. valentinus from the Verd River, Masalaves, Spain (UGSB 21787); T. Operculum of a specimen conforming to T. valentinus from the same locality as Q-S (UGSB 22087). All specimens, except Q-S, were used in the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 9. Theodoxus fluviatilis (Linnaeus, 1758). A - D. Specimen collected close to Oued Laabid, Morocco (UGSB 18106) (Fig. 2); E - H. Specimen from the Danube River, Woerth an der Donau, Germany (UGSB 24173); I - L. Specimen (T. euxinus - morphotype) collected in the Papuc Creek, Kiyikoey, Turkey (UGSB 24172) (Fig. 2); M - P. Specimen (T. euxinus - morphotype) from Ovidiopol, Ukraine (UGSB 18124); Q - S. Specimen (T. heldreichi - morphotype) collected in Lake Egirdir, Turkey (UGSB 20361); T, U. Specimen (T. danasteri - morphotype) collected in Krasna Kosa, Ukraine (UGSB 18417) (Fig. 2); V. Opercula of a T. danasteri - morphotype from Lake Skadar, Montenegro (UGSB 24171). Specimens A-D, I-L and T-U were used in the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 10. Theodoxus fluviatilis (Linnaeus, 1758). A - D. Specimen (conforming to T. sarmaticus) from the Dnieper-Bug estuary, Ukraine (UGSB 18328); E - H. Specimen (T. subthermalis - morphotype) from Novy Afon, Abkhazia, Georgia (UGSB 18402); I - K. Syntype of N. saulcyi from near the Penteli Monastery, Greece (MHNG-MOLL- 111736); L. Specimen (T. saulcyi - morphotype) from Stilos, Crete, Greece (UGSB 20519) incorporated into the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 11. Theodoxus gloeri Odabasi & Arslan, 2015. A - C. Paratype from Balikdami Wetland-Sakarya River, Eskisehir, Turkey (coll. Gloeer). Scale bar: 1 mm.

Figure 12. Type locality of Theodoxus gurur Sands & Gloeer sp. nov. A, B. Suyunbasi spring complex, Ayrancilar, Izmir, Turkey, 38.24826 ° N, 27.28117 ° E.

Figure 13. Theodoxus gurur Sands & Gloeer sp. nov. A - D. Holotype from the Suyunbasi spring complex, Ayrancilar, Izmir, Turkey stored in NMNL (RMNH. MOL. 342197); E - G. Paratype from same locality and storage facility (RMNH. MOL. 342199). Scale bars: 1 mm.

Figure 14. Radula of Theodoxus gurur Sands & Gloeer sp. nov. paratypes (UGSB 20689). A. Portion of the radula showing full sets of teeth; B. Magnified view of the central and lateral teeth; C. Magnified view of the lateral and marginal teeth; D. Magnified view of the first row of marginal teeth; E. Merging point between the first and second rows of marginal teeth; F. Magnified view of the faces of inner marginal teeth belonging to the first row. Scale bars: 100 μm (A-D), 20 μm (E-F).

Figure 15. Theodoxus jordani (G. B. Sowerby I, 1836). A - D. Specimen from the Avakas Gorge, Peyia, Cyprus (UGSB 18321) incorporated into the phylogeny (Fig. 2); E - H. Specimen collected in the Ceyhan River, Eski Misis, Adana, Turkey (UGSB 20777); I - L. Specimen from the Orontes River, Antakya, Hatay, Turkey (UGSB 24175) used in the phylogeny (Fig. 2); M - O. Specimen (T. euphraticus - morphotype) from the Seyed Hosein Park spring, near the Bishapur, Fars, Iran (UGSB 22233); P - R. Topotype of N. jordani from the River Jordan, Israel (UGSB 24177) incorporated into the phylogeny (Fig. 2); S, T. Specimen (T. euphraticus - morphotype) from the Karun River, Ahvaz, Iran (UGSB 21681); U. Specimen (T. niloticus - morphotype) collected in the Nile River, Egypt (UGSB 24178) used in the phylogeny (Fig. 2); V. Specimen (T. euphraticus - morphotype) from the Karun River, Ahvaz, Iran (UGSB 21682). Scale bars: 1 mm.

Figure 16. Theodoxus jordani (G. B. Sowerby I, 1836). A, B. Syntype of N. euphratica from the Euphrates River at Samawah, Iraq (ZMZ 528916); C - E. Syntype of N. michonii from Syria (MHNG-MOLL- 111706); F - H. Syntype of N. karasuna collected from the Karasu River, south-eastern Turkey (ZMZ 528937); I, J; K, L. Two syntypes of N. ponsoti from Lake Muzayrīb, Syria (MNHN-IM- 2000 - 32754); M. Syntype (labelled as paratype) of N. ponsoti from Lake Muzayrīb (MT 820, RBINS); N. Syntype of N. jordani var. turris collected in the Sea of Galilee (ZMZ 528930); O, P. Syntype of N. bellardii from the Litani River, Beqaa valley, Lebanon (ZMZ 528918). Scale bars: 1 mm.

Figure 17. Theodoxus jordani (G. B. Sowerby I, 1836). A - C. Syntype of N. meridionalis var. mesopotamica from near Diyarbakir, Turkey (ZMZ 528914); D, E. Specimen (T. mesopotamicus - morphotype) collected in Sanliurfa, Turkey (UGSB 23426) and used in the phylogeny (Fig. 2); F - H; K - M. Two syntypes of N. cinctella collected at the source of River Chabur near Ras al-Ayn, Syria (ZMB / Moll 21732); I, J. Topotype of N. cinctella from the same locality (UGSB 18762). Scale bars: 1 mm.

Figure 18. Theodoxus macri (G. B. Sowerby II, 1849). A - D. Specimen collected close to Harbiye Falls, Harbiye, Antakya, Turkey (UGSB 24179); E - H. Specimen from Lake Yenisehir, Reyhanli, Turkey (UGSB 24180); I, J. Specimen from Lake Balik, Adalar, Turkey (UGSB 24181). All specimens (A-J) were used in the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 19. Theodoxus major Issel, 1865. A, B. Specimen (T. pallasi - morphotype) collected in the Caspian Sea, offshore from Aktau, Kazakhstan (UGSB 20712); C, D. Specimen (T. pallasi - morphotype) collected in the Aral Sea, Kazakhstan in 1979 (UGSB 19129); E - H. Specimen (T. pallasi - morphotype) from the Shahpol River, Aliabad Askar Khan, Iran (UGSB 18091); I - K. Specimen of T. major collected at the outflow of Lake Akna, Aknalich, Armenia (UGSB 20482); L - N. Specimen (T. astrachanicus - morphotype) collected in Utlyukskij Liman, Ukraine (UGSB 18130); O, P. Specimen of T. major collected in the Hrazdan River at the inflow of the Yerevan Reservoir, Armenia (UGSB 20496); Q - T. Specimen of T. major from Zoeram, North Khorasan, Iran (UGSB 21661); U, V. Specimen of T. schultzii collected in the Caspian Sea, offshore from Aktau, Kazakhstan (UGSB 20714); W - Y. Lectotype of T. pallasi from Caspian Sea, Dagestan, Russia (ZIN 54547 / 63); Za, Zb. Syntype of N. schultzii from the Caspian Sea (ZIN, no. 5 in systematic catalogue). Specimens E-K and O-T used in the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 20. Theodoxus pallidus (Dunker, 1861). A - D. Specimen from Haji Abad, Fars, Iran (UGSB 22227); E - H. Syntype of N. pallida from southern Iran (ZMB 108.792); I, J; K, L. Two syntypes of N. pallida from southern Iran (ZMB 108.793); M - P. Specimen (T. doriae - morphotype) from a spring near Harat, Yazd, Iran (UGSB 21706); Q, R; S, T; U, V; W - Y. Four syntypes of N. doriae from the thermal springs of Kerman, Iran (MSNG, without coll. no.). Specimens A-D and M-P were used in the phylogeny. Scale bars: 1 mm.

Figure 21. Theodoxus syriacus (Bourguignat, 1852). A - D. Specimen collected at Sultankoeyue, Mardin, Turkey (UGSB 24182); E - H. Specimen from the Yanarsu Stream, Alicli, Turkey (UGSB 20518). I - L. Specimen collected near Basdegirmen, Diyarbakir, Turkey (UGSB 24183); M - O; P - R. Two specimens collected by Bourguignat from Iskenderun, Turkey (MHNG-MOLL- 111712). All UGSB specimens incorporated into the phylogeny (Fig. 2). Scale bars: 1 mm.

Figure 22. Theodoxus velox V. Anistratenko in O. Anistratenko et al., 1999. A - D. Specimen from the Dnieper River, Kiev, Ukraine (UGSB 24186); E - H. Specimen collected in the Danube delta, Vylkove, Ukraine (UGSB 24184) used in the phylogeny (Fig. 2); I, J. Holotype from Dnieper Delta, Zbur'ivka Liman, Ukraine (IZAN); K - M. Specimen from Lake Sapanca, Yeni Esme, Turkey (UGSB 20691). Theodoxus sarmaticus (Lindholm, 1901). N - P; Q - S; T - U. Three syntypes from the Oskol River, near Golubino, Russia stored in ZIN (coll. no. 6099 / 24). Scale bars: 1 mm.

Figure 24. Theodoxus wesselinghi Sands & Gloeer sp. nov. A - D. Holotype collected in the Sakarya River, Caykoey, Bilecik, Turkey (RMNH. MOL. 342200); E - G. Paratype from the same location as the holotype (RMNH. MOL. 342202); H - J. Paratype from Fele, Isparta province, Turkey (RMNH. MOL. 342204); K - M. Paratype from Eflatun Pinari, Konya province, Turkey (RMNH. MOL. 342206). All photographed material (A-M) is stored in NMNL. Scale bars: 1 mm.

Figure 25. Radula of Theodoxus wesselinghi Sands & Gloeer sp. nov. paratypes. A. Portion of the radula showing full sets of teeth (UGSB 20688); B. Magnified view of the central teeth (UGSB 20688); C. Magnified view of the lateral and marginal teeth (UGSB 20686); D. Magnified view of the first and second rows of marginal teeth (UGSB 20688); E. Magnified view of the first row of marginal teeth (UGSB 20686); F. Magnified view of the faces of inner marginal teeth belonging to the first row (UGSB 20685). Scale bars: 100 μm (A-E), 20 μm (F).

Figure 27. Theodoxus wilkei Sands & Gloeer sp. nov. A - D. Holotype (RMNH. MOL. 342208); E - G. Paratype (RMNH. MOL. 342210); H - J. Paratype (RMNH. MOL. 342211). All photographed material is from the Cifteler Spring, Cifteler, Eskisehir, Turkey and stored in NMNL. Scale bars: 1 mm.

Figure 28. Radula of Theodoxus wilkei Sands & Gloeer sp. nov. paratypes (UGSB 20687). A. Portion of the radula showing full sets of teeth; B. Magnified view of the central and lateral teeth; C. Magnified view of the lateral and first and second rows of marginal teeth; D. Magnified view of the lateral teeth; E. The first row of marginal teeth; F. Magnified view of the faces of inner marginal teeth belonging to the first row. Scale bars: 100 μm (A-D), 20 μm (E-F).