Theodoxus baeticus (Lamarck, 1822)

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 baeticus (Lamarck, 1822) Figures 6A-V , 7A-P , 8A-P

Neritina Baetica Lamarck 1822: 188; Martens 1879: 234-235, pl. 23, figs 1, 2; Kobelt 1899: 13-14, pl. 214, figs 1350, 1356.

Neritina varia : Menke 1828: 27 (nomen nudum).

Neritina callosa Deshayes in Geoffroy Saint-Hilaire et al. 1835: 156, pl. 19, figs 16-18; Martens 1879: 232-233, pl. 22, figs 27-30; Kobelt 1899: 11-12, pl. 213, figs 1345, 1346.

Neritina varia Rossmässler 1835: 18; Martens 1879: 225-226, pl. 21, figs 17-19; Kobelt 1899: 9, pl. 213, figs 1338.

Nerita meridionalis Philippi 1836: 159-160, pl. 9, fig. 13.

Nerita Philippii Récluz 1841: 341-342.

Neritina elongatula Morelet 1845: 96-97, pl. 9, fig. 4; Martens 1879: 228-229, pl. 22, figs 16-19; Kobelt 1899: 10-11, pl. 213, figs 1341, 1342.

Neritina inquinata Morelet 1845: 93-94, pl. 9, fig. 2.

Neritina guadianensis Morelet 1845: 95-96, pl. 9, fig. 3; Martens 1879: 231-232, pl. 22, figs 22-26; Kobelt 1899: 16, pl. 215, figs 1357, 1358.

Neritina violacea Morelet 1845: 92-93, pl. 9, fig. 1.

Neritina Velascoi Graells 1846: 20-21, unnumbered plate, figs 25-30.

Neritina Anatensis G.B. Sowerby II 1849: 535, pl. 116, figs 247, 248.

Neritina meridionalis : Martens 1879: 227-228, pl. 4, figs 27-29, pl. 22, figs 11-15; Kobelt 1899: 9-10, pl. 213, figs 1339, 1340.

Neritina Hidalgoi Crosse 1880: 320-322; Kobelt 1899: 12, pl. 214, fig. 1347.

Theodoxus (Neritaea) varius callosus : Bank 2006: 52.

Theodoxus (Neritaea) varius varius : Bank 2006: 52.

Theodoxus baeticus : Glöer 2018: 135-136, figs 5-16; Glöer 2019: 38-39, figs 21, 22.

Theodoxus elongatulus : Welter-Schultes 2012: 27, unnumbered text figures.

Theodoxus meridionalis : Alba et al. 2016: 48, figs 4, 9; Glöer 2019: 46-47, fig. 33.

Theodoxus velascoi : Welter-Schultes 2012: 30, unnumbered text figures.

Theodoxus (Theodoxus) cf. meridionalis : Alba et al. 2016: 44-52, figs 2, 3, 5.

Theodoxus callosus : Glöer 2019: 39-40, fig. 23.

Type locality.

Freshwaters of Andalusia, Spain (no precise locality given).

Type material.

Two syntypes of N. baetica are stored in MHNG (coll. no. MHNG-MOLL-51319) . We designate here the syntype illustrated in Figure 6E-G as lectotype ( MHNG-MOLL-51319) . Forty syntypes of N. meridionalis , consisting mainly of empty shells in addition to a few specimens with operculum, are housed in ZMB (without coll. no.; Glöer 2018) . The holotype (by monotypy) of N. callosa is supposed to be stored in UCBL (coll. no. UCBL-EM 33336), but it could not be found (E. Robert pers. comm. 07/2018) .

Remarks.

Across the Mediterranean region a number of widely used nominal species exist that show considerable variation in shell shape and periostracum patterning, yet relatively similar operculum structures (including the presence of a pseudo-apophysis, ivory colouration of the calcareous base of the operculum, and a minimal rib-shield; Figs 6 - 8 ). These species include T. baeticus , T. callosus (Deshayes in Geoffroy Saint-Hilaire et al. 1835), T. varius ( Rossmässler, 1835), T. meridionalis (Philippi, 1836), T. elongatulus (Morelet, 1845), T. guadianensis (Morelet, 1845), T. velascoi (Graells, 1846), and T. valentinus (Graells, 1846), as well as a number of species already synonymised under the above, including Nerita philippii Récluz, 1841, Neritina inquinata Morelet, 1845, Neritina violacea Morelet, 1845, Neritina anatensis G.B. Sowerby II, 1849, and Neritina hidalgoi Crosse, 1880. Most of these species were described from the Iberian Peninsula. Recent insights from molecular phylogenetics and morphological reviews indicate the presence of either a single species ( T. meridionalis ) or two species ( T. meridionalis and T. valentinus ), while all others may be considered junior synonyms ( Bunje and Lindberg 2007; Ramos 2014; Martínez-Ortí et al. 2015; Alba et al. 2016; Sands et al. 2019a). Based on a reinvestigation of type material, Glöer (2018) recently showed that T. meridionalis is a junior synonym of T. baeticus . Theodoxus baeticus has previously been considered a junior synonym of T. fluviatilis , a view that was first rejected on the basis of molecular data by Bunje and Lindberg (2007). Here, we consider all species listed above except for T. valentinus as synonyms of T. baeticus . Theodoxus valentinus differs from T. baeticus in its unique shell shape, showing a high spire and two bulgy keels. Specimens with similar morphology obtained from nearby the type locality of T. valentinus (near Xàtiva, Spain) grouped with T. baeticus in our analyses (Figs 2 , 8Q-T ; Suppl. material 1: Table S1), which may suggest the two species are synonyms. We refrain here from a final conclusion on the matter until topotypic material of T. valentinus is genetically studied.

Our phylogenetic analysis indicate that T. baeticus diverged from other species likely during the early Pleistocene and shares a close relationship with an undescribed species from Spain (see Sands et al. 2019a) and T. marteli (Pallary, 1918) from northern Africa (Fig. 2 ).

Distribution.

Considering the synonymies proposed here, T. baeticus is a widespread species throughout the Mediterranean region. It is present across the Iberian Peninsula, the Balearic Islands, Sicily, Tunisia, and the Balkans ( Bănărescu 1991; Bandel 2001; Bank 2006; Fehér and Erőss 2009; Zettler and van Damme 2010; Martínez-Ortí et al. 2015; Sands et al. 2019a). Within our study region, the species is only noted from the freshwater drainages of the Gulf of Gökova in south-west Anatolia (Fig. 3A ).

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 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.