taxonID	type	description	language	source
03BF87A3C847FFB0FF3DFBC4FF5CA7F2.taxon	diagnosis	Diagnosis. Small (height up to c. 3 mm), conical to ovoid or occasionally globular shell with weakly to moderately convex whorls; umbilicus closed, chink-like or round and deep; aperture ovoid, with acute adapical tip; protoconch bears distinct, fine wrinkles and spiral threads; transition to teleoconch marked by distinct growth rim; rachidian tooth of radula with two pairs of basal cusps. Bursa copulatrix and seminal receptacle rs- 1 absent in female genitals.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C847FFB0FF3DFBC4FF5CA7F2.taxon	discussion	Remarks. The updated morphological diagnosis is based on previously collected data (especially concerning anatomy) as well as new information encountered during the present revision. The radula, characterised by two pairs of basal denticles on the rachidian tooth, differs from those found in the hydrobiid subfamily Pyrgulinae, which lacks basal cusps. In combination with anatomical characteristics, this traits was previously used to separate Caspiinae from Pyrgulinae and classify them as a distinct subfamily (Sitnikova & Starobogatov 1998). Hydrobiinae have one or two pairs of basal denticles on the rachidian tooth and have a bursa copulatrix and seminal receptacle, both of which are missing in Caspiinae. Boeters et al. (2015) reported the presence of rs- 2 in Clathrocaspia milae. Whether or not this feature is characteristic for any other Caspiinae is unknown at present and requires further study. Pyrgulinae have a bursa copulatrix; Turricaspiini, presently considered a tribe within Pyrgulinae (Anistratenko et al. 2019), have a seminal receptacle rs- 1 in addition (see Anistratenko 2008, 2013). Currently, the suprageneric systematic classification of Caspiinae is based on morphology alone. However, a current study in progress using molecular data for C. knipowitschii suggests that Caspiinae form a distinct clade within Hydrobiidae (B. Csányi et al., unpublished data); its subfamily status is thus retained here. Current systematics recognises three supra-specific taxa in the Caspiinae, i. e. Caspia, Clathrocaspia and Ulskia, which are variably treated as distinct genera (Neubauer et al. 2018; Wesselingh et al. 2019) or subgenera (Anistratenko et al. 2019). Here we follow the former approach and treat them as distinct genera. The three genera are differentiated based on details in the ornamentation of the protoconch and teleoconch. The key feature of Caspia is a superficially smooth shell occasionally with a single (or two) fine spiral keel (s) below the suture (Dybowski 1887 – 1888; Logvinenko & Starobogatov 1969; Anistratenko et al. 2019). Clathrocaspia is characterised by a welldeveloped reticulate teleoconch sculpture (e. g. Logvinenko & Starobogatov 1969; Anistratenko 2013; Boeters et al. 2015). Ulskia groups species with a superficially smooth shell, a dome-like, comparatively large protoconch and a microsculpture on protoconch and teleoconch consisting of tiny rows of grains organised in spiral rows. Minute species of the genus Andrusovia Brusina in Westerlund, 1903 are here attributed to the subfamily Caspiinae as well. Andrusovia has formerly been affiliated with a series of different families and even subclasses, including Valvatidae (Westerlund 1903), Planorbidae (Starobogatov 1970), Horatiidae (Starobogatov 2000) or Hydrobiidae (subfamily Belgrandiinae; Kantor & Sysoev 2006: 83). Although the valvatoid shells of Andrusovia strongly differ from those of Caspia, Ulskia and Clathrocaspia, the protoconch shares the unique type of growth and ornamentation typical among Caspiinae. Also, Andrusovia shares a similar type of spirally arranged teleoconch microsculpture with Ulskia. In addition, with an overall comparable size of the species involved, we consider these features evidence for grouping Andrusovia in Caspiinae. The systematic list following below is ordered alphabetically after genus and species and includes (i) species presently considered accepted, (ii) species of doubtful identity (taxa inquirenda and nomina dubia), and (iii) species that have previously been affiliated with Caspiinae but do not belong in the subfamily according to the present revision.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFB0FF3DFCC0FC32A038.taxon	type_taxon	Type species. Andrusovia dybowskii Brusina in Westerlund, 1903 (“ 1902 ”); by original designation. Caspian Sea, Recent.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFB0FF3DFCC0FC32A038.taxon	discussion	Remarks. The genus Andrusovia represents one of the most enigmatic groups of the Caspian Sea gastropods. Four species have been described (Westerlund 1903; Logvinenko & Starobogatov 1969; Starobogatov 2000), but the identity and validity of all was previously uncertain (Wesselingh et al. 1999). This was partly rooted in the absence of type material and partly in the short and ambiguous description provided for A. dybowskii by Brusina in Westerlund (1903). Because of the minute size, the shell morphology of Andrusovia has been studied in detail only recently and only based on fossil material (Neubauer et al. 2018). Since no animal has ever been found alive, none of the four species has been investigated anatomically; even whether these snails have an operculum is unknown. The recent detection of the syntypes of A. dybowskii and paratypes of Logvinenko & Starobogatov (1969) and Starobogatov (2000) allows for a proper revision of the species involved for the first time. Based on the comparison of all type material and additional data available, we conclude that only a single species occurs today, A. dybowskii. For Pleistocene specimens previously attributed to A. brusinai by Neubauer et al. (2018), as well as for late Holocene specimens from the South Caspian Basin, we introduce new species.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFBDFF3DFA7FFA28A2F6.taxon	description	Figs 2, 3	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFBDFF3DFA7FFA28A2F6.taxon	materials_examined	Type material. Previously, the syntype material of this species was presumed lost, but it was uncovered in the course of the present study in the “ Caspian Mollusca ” collection of the CNHM. The material consists of 37 specimens, which were split by Brusina into two tubes. A tube with four specimens bears the inscription “ U. ” in Brusina’s handwriting, which very likely means “ unicum ”, a term that Brusina often used to label type specimens in his col-lection (P. Crnčan, pers. comm. 06 / 2020). The handwriting on the labels of the material are near identical to the one on labels of the von Baer collection, confirming that the type material comes from that collection. Letters written by Brusina stored in the “ Caspian Mollusca ” collection of the CNHM prove that Władysław Dybowski sent material to Brusina after publication of his monograph on Caspian molluscs (W. Dybowski 1888: 53, 64 footnote). In a letter from Brusina to Benedykt Dybowski, along with which he sent material back to Lviv (dated 14 June 1905), he referred to the new species Andrusovia Dybowskii from “ Detritus [...] aus 46 Sežen Tiefe ”. This matches the label on the material in Zagreb (“ I iz 46 sež. dub. ”) as well as that on lot ZB-M W. Dyb. 116 (“ Detritus 46 Saž. tief ”). These labels refer to a collection depth of 46 fathoms (Russian “ sažen ” or “ sazhen ”, Croatian “ sežanj ”). At the time the samples were taken, most likely by Ulski during hydrographic expeditions in 1858 to 1864 (Anistratenko et al. 2018), the nautical fathom (morskaya sazhen) measured 1.853 m, denoting a collection of depth of approximately 85 m. Finally, the shells of the type series closely resemble the material from the von Baer collection in terms of morphology and preservation (Fig. 2; compare also Anistratenko et al. 2019), substantiating the interpretation that they originally come from the same lot. In order to fix the identity of Andrusovia dybowskii, we choose as lectotype a specimen from the lot containing four specimens (CNHM ZMKJ 50; Fig. 2 a, b, e); the remaining three shells in that lot are paralectotypes (CNHM ZMKJ 51 – 53). Additionally, several paratypes of other Andrusovia species here considered synonymous are found in MSU; the holotypes are however not traced. This concerns 5 paratypes of A. andrusovi (Lc- 24600, Lc- 24601, Lc- 24604), 2 paratypes of A. brusinai (Lc- 24598, Lc- 24599) and 8 paratypes of Horatia marina (Lc- 24613, Lc- 24614). Type locality. “ Mare Caspium ” (Caspian Sea) (Table 1, locality 26). The depth indicated on the collection labels (“ I iz 46 sež. dub. ”, meaning “ collected from a depth of 85 meters ”; see above) confines the type locality to the Middle or South Caspian Basin. Type locality of A. andrusovi: Caspian Sea off Cheleken Peninsula, Turkmenistan (locality 19); the paratypes studied herein come from a locality to the south of the type locality (locality 18). Type locality of A. brusinai: Eastern part of the middle Caspian Sea (locality 8); the paratypes derive from locality 22 in the South Caspian Basin. Type locality of H. marina: Northern part of the middle Caspian Sea (locality 2); the paratypes come from locality 22. Other material. 33 specimens in the “ Caspian Mollusca ” collection of the CNHM (CNHM ZMKJ 49) and 61 specimens (ZB-M W. Dyb. 8, 26 – 28, 35, 70, 116) from unknown locations in the Caspian Sea (locality 26).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFBDFF3DFA7FFA28A2F6.taxon	description	Description. Broad conical shell with up to three whorls; measuring up to 1.34 mm in height, 1.27 mm in width. Protoconch consists of c. 1.05 – 1.15 whorls measuring approximately 380 – 415 µm; surface bears distinct, densely malleate sculpture, occasionally accompanied by 3 – 4 spiral threads on initial half whorl; triangular portion reaching from lower suture at c. 0.5 – 0.8 whorls to upper suture at end of protoconch lacks malleate sculpture but bears irregular, bulgy growth rims; protoconch – teleoconch transition marked by strong growth rim. Teleoconch whorls moderately convex, typically weakly flattened and weakly stepped, separated by distinct suture. Spire height variable: last whorl attains c. 71 – 84 % of total shell height. Umbilicus funnel-shaped, round, very narrow. Umbilicus may be surrounded by bulge in some specimens, which is occasionally more pronounced and forms distinct keel. Aperture broadly ovoid to near circular, strongly attached to base of last whorl, which sometimes results in weak concavity at parietal margin and slightly asymmetric shape. Peristome thin or sometimes slightly thickened; distinctly sinuate in lateral view, with protruding central part and indentations adapically and abapically. Fine prosocyrt growth lines cover shell. In a few specimens, faint irregular spiral grooves appear on last whorl.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFBDFF3DFA7FFA28A2F6.taxon	discussion	Remarks. The previous concepts of A. dybowskii applied in the literature were based on a low-spired morphology. While the phrase “ conoidea vel discoidea ” (i. e. conical or disciform) in the original description comprises a great variety of shell shapes, Logvinenko & Starobogatov (1966) considered only disciform specimens to represent Andrusovia dybowskii. This led them to believe the genus belongs in Planorbidae, and they listed it as subgenus of Anisus and synonymised the species with Anisus eichwaldi (Clessin & W. Dybowski in W. Dybowski, 1887). Starobogatov (2000) revised this opinion and considered shells with depressed spire to represent A. dybowskii and classified Andrusovia in Horatiidae. Based on this concept, he introduced two more species based on variation of spire height: Andrusovia brusinai for high-spired forms and Andrusovia andrusovi for specimens with a spire height intermediate between A. brusinai and A. dybowskii (sensu Starobogatov 2000). He additionally classified Horatia marina Logvinenko & Starobogatov, 1969 in Andrusovia as well. He already noted the similarity of that species to his A. brusinai, but despite strong overlap in all measurements and ratios he still considered both species distinct. The newly discovered type series demonstrates that the previous concepts of A. dybowskii applied by Logvinenko & Starobogatov (1966) and Starobogatov (2000) were misapplications: the type series contains only forms that are high-spired or slightly less so; no disciform specimens are found (which makes Brusina’s original description quite misleading). Comparing the available type material for all three species shows that they cannot be sufficiently separated. Specifically, A. brusinai and A. marina (Fig. 2 g, h, y – aa, ad, ae), which partly co-occur in the same localities, are near identical to the type series of A. dybowskii. The comparably low-spired morphology of Andrusovia andrusovi (Fig. 2 ae) is not found among the type series of Brusina and only few shells in the von Baer collection come close (Fig. 2 x). Given the variation in spire height observed among the specimens of A. dybowskii, we consider A. andrusovi to range within its variability. In addition to variation in spire height, some specimens (particularly the more slender ones) may bear a weak bulge (Fig. 2 f, s, z) or a distinct keel (Fig. 2 l, v, aa) surrounding the umbilicus. This trait variability is also seen in the type series. Given the overall high morphological variability of A. dybowskii and the variable expression of this trait, we consider it to range with intraspecific variation. If live material of this species could be collected, a molecular study might provide more insights about the systematic significance of this and other traits. In summary, we consider all these morphologies to belong to a single polymorphic species, A. dybowskii, rendering A. andrusovi, A. brusinai and A. marina its junior subjective synonyms. This also makes the subgenus Horatia (Caspiohydrobia) Logvinenko & Starobogatov, 1969, with H. marina as type species, a junior subjective synonym of Andrusovia (see also Anistratenko et al. 2019).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C846FFBDFF3DFA7FFA28A2F6.taxon	distribution	Distribution. Endemic to the Caspian Sea, found in the Middle and South basins at depths between 34 and 311 m.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	description	Fig. 4 urn: lsid: zoobank. org: act: 528249 A 2 - 5494 - 4 E 14 - BA 1 F- 4 AB 37949 EA 0 D	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	materials_examined	Type material. Holotype: RGM 1309839: 1.81 x 1.80 mm (shell height x width; Fig. 4 b, c, h). Paratypes: RGM 1309840: 1.52 x 1.44 mm (Fig. 4 a, d, g); LV 201509 (MSU): 1.54 x 1.55 mm (Fig. 4 e, f, i). Type locality. Selitrennoye, Astrakhan region, Russia (Table 1, locality 1); northern Caspian Basin; GPS coordinates: 47 ° 10 ’ 21.19 ” N, 47 ° 26 ’ 25.41 ” E (WGS 84). Age. Hyrcanian, early Late Pleistocene, c. 107 ± 7 ka (van de Velde et al. 2020). Other material. 36 specimens (RGM 1310206).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	etymology	Etymology. Referring to the supposed position as predecessor to modern Andrusovia. The name is a noun in apposition.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	diagnosis	Diagnosis. Low trochiform, conical, comparably large Andrusovia with up to four well rounded whorls, wide umbilicus, broadly ovoid aperture, weakly sinuate and weakly thickened peristome.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	description	Description (emended from Neubauer et al. 2018). Shell broad trochiform, about as high as wide, with up to 4 whorls. Rarely, specimens with slightly elevated spire occur. Protoconch high domical, about semi-circular in profile; initial part immersed; consists of 1.1 whorls, measuring 300 μm in diameter; nucleus about 90 μm wide; protoconch surface finely but strongly malleate near lower suture, rest appears eroded; P / T boundary sharp, marked by massive growth constrictions near lower suture. Teleoconch whorls highly convex, with maximum convexity in adapical half, producing slightly stepped spire. Last whorl attains 74 – 81 % of shell height. Aperture broadly ovoid, slightly inclined, with faint concavity at contact to penultimate whorl. Peristome slightly thickened and expanded at columella and base; sinuate in lateral view, with weakly protruding central part and weak adapical indentation. Umbilicus wide, deep. Fine prosocyrt growth lines cover shell. On one specimen, traces of spiral threads occur on base.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	discussion	Remarks. Neubauer et al. (2018) wrongfully attributed this species to the extant Andrusovia brusinai, which is here considered a junior synonym of Andrusovia dybowskii (see above). Andrusovia antecessor sp. nov. differs from that species in the larger size, the more whorls while having an equally small (compared to subfossil shells) or smaller (relative to recent shells) protoconch, the more regular coiling resulting in a perfectly conical shape, and the rounded whorls. The overall similarity (and the lack of other known species) suggests that both species are closely related; given the age, A. antecessor sp. nov. might be a phylogenetic predecessor of A. dybowskii. The smaller protoconch (and thus smaller hatching size) combined with a larger adult size of Andrusovia antecessor sp. nov. compared to modern A. dybowskii suggests a faster growth rate or, alternatively, a longer lifetime. Growth rates in gastropods typically correlate positively with temperature (e. g. Kevrekidis & Wilke 2005; Shanahan et al. 2005; McCreesh et al. 2014). Similarly, the time of hatching can occur earlier under warmer conditions (Cancino et al. 2003). The scenario of an increased growth rate in A. antecessor sp. nov. as a function of temperature fits well to the supposed warmer climate during the Hyrcanian (Yanina 2014; Krijgsman et al. 2019).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84AFFBBFF3DFF49FE5BA167.taxon	distribution	Distribution. Endemic to the Caspian Sea, known only from the Late Pleistocene strata of the type locality. Reconstructions of the paleoecology suggest a shallow (15 – 25 m), lower mesohaline (5 – 8 psu) open lake environment (van de Velde et al. 2020).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	description	Fig. 5 urn: lsid: zoobank. org: act: 3 A 413153 - 1 A 98 - 47 A 7 - A 93 A-B 00 CC 7 CE 8 E 04	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	materials_examined	Type material. Holotype: RGM 1310292: 0.83 x 0.90 mm (Fig. 5 a, j, k, r). Paratypes: RGM 1310293: 0.93 x 0.99 mm (Fig. 5 b, m); RGM 1310294: 0.81 x 0.89 mm (Fig. 5 c, d, l, q, s); RGM 1310295: 0.75 x 0.81 mm (Fig. 5 e, f, i, p, t). Type locality. South Caspian Basin off Kura delta, Azerbaijan (locality 25 f, sample 14 - 1); GPS coordinates: 39 ° 17 ’ 13.14 ” N, 49 ° 36 ’ 7.62 ” E (WGS 84). Age. Subfossil, late Holocene (Hoogendoorn et al. 2005). Other material. Three specimens from localities 25 d and 25 f (RGM 1310296 – 1310298).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	etymology	Etymology. From Cyrus, the Latin name of the Kura River.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	diagnosis	Diagnosis. Low trochiform, conical, small Andrusovia with up to three convex, slightly stepped whorls, wide umbilicus, broadly ovoid aperture, weakly sinuate and weakly thickened peristome, strongly wrinkled protoconch with faint spiral threads and teleoconch microsculpture consisting of fine, densely spaced, slightly irregular, raised spiral threads, which are typically dissected into elongate beads.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	description	Description. Small shell, slightly broader as high, with up to three whorls with stepped appearance. Protoconch low domical, cap-like, consisting of 1 whorl that measures c. 290 – 305 µm; protoconch covered with densely malleate sculpture that may become wider meshed and spikier on second half; faint traces of up to four spiral threads appear on first half near lower suture in some specimens; final triangular portion reaching from lower suture to end of protoconch, starting at c. 0.75 whorls, devoid of malleate sculpture but bearing growth rims that increase in strength towards transition to teleoconch; transition marked by growth stop and onset of fine prosocyrt growth lines. Teleoconch whorls covered with dense microsculpture consisting of fine, densely spaced, slightly irregular, raised spiral threads, which are typically dissected into elongate beads. Suture incised and deep. Body whorl attains c. 80 % of total shell height, forms shallow base. Aperture wide, ovoid, with weak notch at contact to penultimate whorl; umbilicus circular, wide, deep. Peristome slightly thickened, sinuate.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	discussion	Remarks. The new species resembles A. dybowskii superficially concerning the low trochiform shape, but it is distinctly smaller, has a lower spire, a smaller protoconch (290 – 305 µm versus 380 – 415 µm) at approximately the same number of whorls, more convex whorls and a teleoconch microsculpture that is so far unknown in any other Andrusovia species. Only specimens formerly attributed to Andrusovia andrusovi (here considered a synonym of A. dybowskii; see above) more closely match A. cyrensis sp. nov. in terms of the depressed shell, but we consider the larger size, larger protoconch, more thickened shell and (apparent) lack of teleoconch microsculpture (Fig. 2 ae), 3 c, h) sufficient to distinguish them on the species level. The Pleistocene Andrusovia antecessor sp. nov. is even larger and has a higher spire with more whorls.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84DFFB9FF3DFBBCFF4DA481.taxon	distribution	Distribution. Caspian Sea. So far only known from the late Holocene of the Kura delta deposits (South Caspian Basin).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84FFFB9FF3DFD98FEFFA7C9.taxon	type_taxon	Type species. Caspia baerii Clessin & W. Dybowski in W. Dybowski, 1887; by subsequent designation (Westerlund 1903). Caspian Sea, Recent.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84FFFA7FF3DFCCFFE0FA436.taxon	description	Fig. 6	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84FFFA7FF3DFCCFFE0FA436.taxon	materials_examined	Type material. Lectotype (ZB-M W. Dyb. 96) and 116 paralectotypes (ZB-M W. Dyb. 95 - 97) (designated by Anistratenko et al. 2019). Type locality. “ Kaspi-See ” (Caspian Sea, without further details; Table 1, locality 26). Other material. 41 specimens in Starobogatov’s ZIN collection labelled as “ Caspia tadjallipouri ” (an unavailable collection name), collected from the eastern part of the middle Caspian Sea (locality 7).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84FFFA7FF3DFCCFFE0FA436.taxon	description	Description. Shell small (up to 2.05 mm in height, 0.96 mm in width), slender, elongated-ovoid to slightly cylindric, with up to five whorls. Protoconch comprises c. 1.1 – 1.2 whorls bearing minute wrinkles and fine spiral threads (7 in Fig. 6 r) placed at irregular interspaces; final 0.1 whorls of protoconch thickened (sometimes markedly), showing no or only traces of sculpture, except irregular growth lines; transition to teleoconch abrupt, marked by growth rim and onset of growth lines. Teleoconch whorls low convex, sometimes flattened in whorl centre, sometimes producing step-like appearance. Sometimes 1 or 2 fine spiral threads appear below suture, occasionally accompanied by weak striation across whole whorl profile. Last whorl attains slightly more than half of shell height. Aperture ovoid, with weak adapical angulation, sometimes slightly expanded laterally. Umbilicus covered by inner lip. Shell surface smooth, translucent, glossy. Growth lines slightly prosocline and faintly sigmoid.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84FFFA7FF3DFCCFFE0FA436.taxon	discussion	Remarks. The slender shell of Caspia baerii and the weak teleoconch striation allow distinction from all other Caspiinae. The shell morphology is variable to some extent with respect to shell elongation and the expansion of the aperture, but these differences range within intraspecific variability. In Starobogatov’s material we found the “ holotype ” and 40 “ paratypes ” of a catalogue taxon he intended to describe as “ Caspia tadjallipouri ”. The shells of “ Caspia tadjallipouri ” fit very well to the lectotype of Caspia baerii in terms of shape and sculpture and are considered conspecific herein (Fig. 6 g – j, q). W. Dybowski (1887: 36 – 37) and subsequent authors (Kolesnikov 1950; Golikov & Starobogatov 1966, 1972; Logvinenko & Starobogatov 1969) mentioned one or two fine spiral keels below the suture. However, the type material only occasionally shows weak spiral threads, which typically overlap visually with the base of the previous whorl shining through the translucent shell, giving the misleading impression of a stronger keel or bulge (compare light and SEM photographs, Fig. 6 e and k, f and l).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C84FFFA7FF3DFCCFFE0FA436.taxon	distribution	Distribution. Caspian Sea. This species was mentioned from depths between 200 and 400 m in the South Caspian Basin off Azerbaijan (Mirzoev & Alekperov 2017, who reported the species as Turricaspia baerii), but the taxonomy applied in that paper is questionable and needs re-examination. No depth data is available for the material we studied (locality 7), but according to the coordinates it is approximately 70 m. No living specimens of C. baerii have been found to date.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFD0FFE8DA2B5.taxon	description	Fig. 8	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFD0FFE8DA2B5.taxon	materials_examined	Type material. Holotype (ZIN # 1 in systematic catalogue) and 74 paratypes (ZIN collection). Four specimens labelled as paratypes of Caspia brotzkajae (IZAN, unnumbered lot) from a late Holocene drilling borehole taken in the southern part of Odessa region, Ukraine (Table 1, locality 32), do not belong to that species but instead to C. knipowitschii (see there). Type locality. Caspian Sea shores of Dagestan, Russia, at a depth of ca. 60 – 75 m (locality 10). The paratypes were retrieved from locality 12 close by the type locality. Other material. 17 specimens in Starobogatov’s collection, marked as “ type material ” of “ Caspia alighadzhievi ”, an unavailable catalogue name; collected in 1957 and 1960 near Derbent (Dagestan, Russia) at a depth of 60 m and in the eastern part of the middle Caspian Sea at a depth of 73 m (localities 6, 11).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFD0FFE8DA2B5.taxon	description	Description. Broadly ovoid shell with about 4 whorls and large body whorl (ratio of body whorl height / shell height approximately ¾). Protoconch consists of about 1.2 whorls that measure c. 400 μm, bearing irregular wrin-kles and faint spiral threads. Teleoconch covered by fine but distinct reticulate sculpture, with numerous spiral keels that are equally prominent across whorl profile and have interspaces that are approximately as wide as keels; only uppermost 1 – 2 keels are usually more prominent and slightly wider spaced; in some shells, uppermost keel forms weak subsutural ramp that results in slightly stepped outline. Aperture wide, sometimes laterally expanded; umbilicus covered in most shells, sometimes present as thin slit.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFD0FFE8DA2B5.taxon	discussion	Remarks. Compared to other Clathrocaspia species, C. brotzkajae is more bulbous, has a larger body whorl and a more expanded aperture. Only C. logvinenkoi from the Black Sea Basin is even more bulbous but smaller. Originally, four specimens from the Holocene of the Danube Delta, Ukraine, were attributed to that species (Anistratenko & Prisjazhnjuk 1992). These shells are more slender and have a smaller aperture; they rather resemble C. knipowitschii and are referred to this species herein. In turn, the specimen illustrated as “ Pyrgula knipowitchi ” in Logvinenko & Starobogatov (1969) from the Caspian Sea shows a very bulky shell that is highly reminiscent of and considered conspecific with Clathrocaspia brotzkajae. In the collection of Starobogatov we found the “ holotype ” and 16 “ paratypes ” of a catalogue taxon Starobogatov named “ Caspia alighadzhievi ”. The material shows close similarities with the holotype of C. brotzkajae (Fig. 8 g – j, m), described from the same region, and we consider Starobogatov’s material to belong to that species.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFD0FFE8DA2B5.taxon	distribution	Distribution. Known only from the Caspian Sea shores of Dagestan, Russia. No living specimens have been encountered.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFE4CFC0DA7F7.taxon	type_taxon	Type species. Caspia pallasii Clessin & W. Dybowski in W. Dybowski, 1887; by original designation. Caspian Sea, Recent.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C851FFA7FF3DFE4CFC0DA7F7.taxon	discussion	Remarks. Because of the number of Clathrocaspia species presently accepted and the different concepts that have been applied to these species (see Remarks sections below), we provide here an overview of all accepted Clathrocaspia species to allow for comparison of relevant shell traits (Fig. 7).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C853FFA3FF3DF9F4FE29A20A.taxon	description	Figs 9, 10 Pyrgula (Caspia) gaillardi, N. Espece — Tadjalli-Pour 1977: 107, fig. 8. C. [aspia] (Cl. [athrocaspia]) gaillardi (Tadjalli-Pour, 1977) — Sitnikova & Starobogatov 1998: 1363 – 1364, fig. 1.13.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C853FFA3FF3DF9F4FE29A20A.taxon	materials_examined	Type material. Holotype, Faculté de Médecine Vétérinaire de l’Université de Téhéran; not studied. One paratype should be in ZIN (“ Un spécimen paratype a été déposé au Musée Malacologique de Leningrad ”; Tadjalli-Pour 1977: 107), but it could not be found. Type locality. Caspian Sea, Astara-Hachtpar (Iran), 0 – 30 m. Other material. Kantor & Sysoev (2006: 87) were unable to locate identified samples in the ZIN collections, but we retrieved a lot in the Starobogatov collection containing 12 specimens determined as “ Caspia gaillardi ”, collected in the Middle Caspian Basin off Apsheron Peninsula (Table 1, locality 13). Additional five specimens come from the South Caspian Basin off Cheleken Peninsula (locality 18, labelled as “ Caspia subgmelini ”) and six specimens derive from late Holocene deposits of the Kura delta (localities 25 a and 25 f, RGM 1310299 – 1310304).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C853FFA3FF3DF9F4FE29A20A.taxon	description	Description. Shell comparably large, broadly conical, consisting of up to 5 low to moderately convex, slightly stepped whorls. Protoconch bulbous, ranges around 320 – 335 µm and consists of c. 1.2 whorls; surface strongly sculptured, with distinct wrinkles that increase in size and become more irregular towards teleoconch; final triangu-lar part of protoconch always devoid of wrinkles (Fig. 10 a – i); additionally, spiral threads occur on first half whorl (Fig. 10 e, g, h). Teleoconch covered with strong reticulate sculpture, with sharp ribs and subquadrangular interspaces; spirals dominate, axials faintly sigmoid. Aperture ovoid, sometimes detached, leaving slit-like umbilicus; in other cases, basal columellar margin expands beyond columella and covers umbilicus.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C853FFA3FF3DF9F4FE29A20A.taxon	discussion	Remarks. The material in the Starobogatov’s collection fits well to C. gaillardi as described and illustrated by Tadjalli-Pour (1977), regarding the broad conical shape with five whorls, the marked sutures, the strong sculpture and the comparably large size. Similarly, five specimens labelled in Starobogatov’s collection as “ Caspia subgmelini ” (an unavailable collection name; Fig. 9 f – i) collected off Cheleken Peninsula fit well to C. gaillardi, and so do specimens from the Holocene deposits off the Kura delta (Fig. 9 j – n). Some of the specimens only have a less stepped spire than is typical of C. gaillardi, but we consider this to range within intraspecific variability. Sitnikova & Starobogatov (1998) provided data on the female reproductive anatomy and the radula of this species. They noted that the studied morphological characters of C. gaillardi and C. gmelinii are almost identical. Also Wesselingh et al. (2019) listed the species as a tentative synonym of C. gmelinii. However, C. gmelinii is much smaller and has a less stepped outline and a weaker reticulate sculpture. Specimens of C. gaillardi also show a certain similarity to C. pallasii, but the latter species can be distinguished by its larger, bulbous protoconch and the more slender shell. The stepped teleoconch of C. gaillardi and the comparably high last whorl also differentiates it from C. isseli.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C853FFA3FF3DF9F4FE29A20A.taxon	distribution	Distribution. Caspian Sea, South Basin to southern part of Middle Basin, known only from shallow waters (max. depth of 44 m).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C854FFA0FF3DFF49FDC3A58E.taxon	description	Fig. 11	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C854FFA0FF3DFF49FDC3A58E.taxon	materials_examined	Type material. Lectotype (ZB-M W. Dyb. 77) and 82 paralectotypes (ZB-M W. Dyb. 77 and 91) (designated by Anistratenko et al. 2019). Type locality. “ Kaspi-See ” (Caspian Sea, without further details; Table 1, locality 26). Other material. Thirty specimens in Starobogatov’s collection (ZIN) taken off Cheleken Peninsula (Turkmenistan; locality 20) and nine specimens from the eastern part of the middle Caspian Sea, labelled in Starobogatov’s collection as “ Caspia valkanovi subbaeri ” (locality 3) and “ Caspia mediocaspica ” (localities 3, 4), two unavailable collection names, are referred to C. gmelinii herein. In addition, 29 specimens labelled as “ sowinskii ” [sic] were found in the Starobogatov collection (ZIN). Although not unambiguously stated, it is likely to be the type series of Pyrgula sowinskyi Logvinenko & Starobogatov, 1969. The material was collected from the western part of the South Caspian Sea close to the Kura river mouth and Salyan berth at a depth of 88 m (locality 24). No other identified material of that species has been found in ZIN (Kantor & Sysoev 2006: 104). Several of the probable paratypes match C. gmelinii and are referred to here; the rest is referred to C. pallasii.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C854FFA0FF3DFF49FDC3A58E.taxon	description	Description. Small, slender shell with tightly packed, low convex whorls. Protoconch low domical, comparably small (c. 320 – 345 µm), bearing faint, irregularly distributed wrinkles and spiral threads (Fig. 11 t – v). Teleoconch covered by delicate reticulate sculpture that is usually restricted to last two whorls, sometimes even to last whorl. Aperture slender ovoid, typically tightly attached.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C854FFA0FF3DFF49FDC3A58E.taxon	discussion	Remarks. Specimens labelled as “ Caspia valkanovi subbaeri ” and “ Caspia mediocaspica ” from the eastern part of the middle Caspian Sea may be considered varieties with slightly larger shells (“ subbaeri ”) or slightly rounder whorls (“ mediocaspica ”), but they match C. gmelinii in terms of the overall shape and the striated to weakly reticulated surface and the small protoconch (Fig. 11 i, j, o, p). Furthermore, several specimens of the (presumed) type series of Pyrgula (Caspia) sowinskyi Logvinenko & Starobogatov, 1969 fit well to the type series of C. gmelinii and are considered synonymous (Fig. 11 k – n, s). A part of that material, however, matches shells of C. pallasii in terms of the elongate shape and bulbous protoconch. Since there is no proof of the material being the actual type material and which of the specimens is the holotype, the true identity of P. sowinskyi remains dubious. Logvinenko & Starobogatov’s (1969) concept of C. gmelinii, in turn, does not match well with the type series; the specimen they illustrate rather resembles C. gaillardi in the larger, broader, stepped shell. Clathrocaspia gmelinii differs from C. pallasii in its more ovoid shell with shallower suture, the more delicate reticulate sculpture and especially the smaller protoconch (c. 320 – 345 µm for C. gmelinii versus c. 420 – 430 µm for C. pallasii; Figs 11 t – v), 12 r, s). A morphologically even closer species is C. knipowitschii described from the Dniester river liman in the Black Sea Basin (Makarov 1938). Clathrocaspia knipowitschii has typically a broader shell and more convex whorls, but there are specimens with low convex whorls as well (Fig. 13 g, h, j) that strongly remind of C. gmelinii. The identities of the two species have not been assessed anatomically or genetically yet (also due to the lack of living material). Until further information becomes available, we consider them as distinct species, with C. knipowitschii being restricted to the Black Sea Basin and C. gmelinii being a Caspian element. Live specimens of C. gmelinii in the Caspian Sea have only been studied by Sitnikova & Starobogatov (1998), who provided data on the female reproductive anatomy and the radula.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C854FFA0FF3DFF49FDC3A58E.taxon	distribution	Distribution. Caspian Sea. The exact locality and depth range of the type series is not known, the other studied material was retrieved from the eastern part of the Middle Basin and the north-eastern and north-western parts of the South Basin from depths of 32 – 88 m.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFA0FF3DFE94FC24A01E.taxon	description	Fig. 12 i – l, q	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFA0FF3DFE94FC24A01E.taxon	materials_examined	Type material. Holotype not traced, should be in ZIN. In contrast to Kantor & Sysoev (2006: 100), who stated that no identified material of this species is found in ZIN, we could locate two lots with 23 specimens in the collection of Starobogatov, which he labelled as “ Caspia isseli ”. Likely, these are paratypes of C. isseli. However, the collection includes a variety of morphologies, some of which match the typical C. isseli as described by Logvinenko & Starobogatov (1969) (e. g. Fig. 12 i, j), while some resemble C. pallasii closely and should be classified under that species (e. g. Fig. 12 g, h). Given the lack of the holotype, the identity of C. isseli is doubtful. For the time being, we use all of the presumed paratypes that are not misidentified C. pallasii to characterise C. isseli. Type locality. Originally given as “ Southern Caspian Sea between 40 – 75 m water depth ” without details on the locality. The presumed paratype material derives from the Caspian Sea off Apsheron Peninsula, Azerbaijan (Table 1, locality 14), and off Cheleken Peninsula, Turkmenistan (locality 21). Other material. A single shell from Holocene deposits of the Kura delta (locality 25 f, RGM 1310305).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFA0FF3DFE94FC24A01E.taxon	description	Description. Slender, elongate, conical shell with up to 5 low convex, tightly coiled whorls. Protoconch bulbous, bears small wrinkles and thin spiral threads throughout (Fig. 12 q). Strong reticulate sculpture covers teleoconch, whereas spiral keels are more prominent than axial ribs (Fig. 12 i – l). Small subsutural ramp occurs above first keel, sometimes resulting in slightly stepped outline (Fig. 12 l). First 1 – 2 keels are always more prominent and separated by wider interspaces than the ones following abapically. Aperture adjoined, base steep.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFA0FF3DFE94FC24A01E.taxon	discussion	Remarks. The material Starobogatov distinguished as C. isseli and C. pallasii contains a mix of both. In addition to the mix up in the type material of C. isseli (see above), Starobogatov’s material of C. pallasii also contains specimens of C. isseli (e. g. Fig. 12 k). Despite their overall similarity in shell shape, C. pallasii can be distinguished from C. isseli by the consistently lower base, the less convex whorls, the slightly detached aperture and the larger and more bulbous protoconch. Clathrocaspia isseli differs from C. gmelinii in its more slender shape.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFA0FF3DFE94FC24A01E.taxon	distribution	Distribution. Endemic to the Caspian Sea, only known from two localities in the South Basin (from depths of 40 and 107 m). Also found in Holocene deposits of the Kura delta.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFACFF3DFA64FECBA58E.taxon	description	Fig. 13 a – d, f – p	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFACFF3DFA64FECBA58E.taxon	description	P. [yrgula] (Caspia) knipowitchi [sic] (Makarov, 1938) — Golikov & Starobogatov 1966: 354, fig. 1 (6).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFACFF3DFA64FECBA58E.taxon	description	Caspia (Clathrocaspia) knipowitchi [sic] Makarov, 1938 — Anistratenko & Prisjazhnjuk 1992: 19, fig. 2 b.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFACFF3DFA64FECBA58E.taxon	materials_examined	Type material. The types of C. knipowitschii are lost. All material of Makarov that was supposedly stored in Odessa was almost certainly destroyed during World War II (M. Son and I. Sinegub, pers. comm. 05 / 2020); despite considerable effort, the material could not be located in any collection. To fix the identity of C. knipowitschii we designate a neotype. Unfortunately, there is no topotypic material from the mouth of Dniester River in any collection we are aware of, and no fresh material was encountered there during an expedition in 2016. Thus, we choose as neotype a specimen from the nearest possible location with similar ecological settings, i. e. the mouth of the Dnieper River near Kherson, from where Makarov (1938) also reported specimens. The neotype (IZAN 522 / 1) fits well to the original description in terms of size, shape and sculpture. The type material of C. makarovi includes the holotype (ZIN 4492 / 1), collected by S. A. Zernov in 23 / 09 / 1908 (during the “ Academician Baer ” steamship expedition), and 126 paratypes (ZIN 4499 / 2 – 4501 / 10), collected by S. A. Zernov in 15 / 08 – 15 / 09 / 1909 (during the “ Meotida ” steamship expedition). Type locality. The neotype comes from the mouth of Dnieper River near Kherson, Kherson region (Ukraine) (Table 1, locality 30 b). The original (lost) type series comes from the mouth of Dniester River. The type locality of C. makarovi is the Dnieper River liman (locality 31). Other material. Fifty two specimens from the neotype locality (IZAN 522, locality 30 b) and three specimens from the close-by locality 30 c (UGSB 25234 – 25236). Further 19 specimens were retrieved from Holocene deposits of near Kiliya, Odessa region, Ukraine (IZAN unnumbered, locality 32); this also includes four paratypes of C. brotzkajae from the same lot referred to C. knipowitschii herein. 228 specimens derive from late Holocene deposits from six piston cores in the Razim-Sinoe lake complex, Romania (RGM 1309843 and unnumbered; localities 33 a – f).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFACFF3DFA64FECBA58E.taxon	discussion	Remarks. Detailed descriptions of Clathrocaspia knipowitschii and C. makarovi were provided by Anistratenko (2013), including information on protoconch, radula and operculum. Here we review all material presently available for both species, including the holotype of C. makarovi. Both species comprise a wide range of shell variability, concerning size, shape (elongate versus more bulky) and whorl convexity. Although typical C. knipowitschii sensu Makarov (1938) (Fig. 13 a, b) and C. makarovi sensu Golikov & Starobogatov (1966) (Fig. 13 c, d, f) can be clearly distinguished, there are numerous intermediate morphologies that do not allow establishing clear species boundaries. Moreover, the different forms co-occur in the same habitats. Only the protoconch of C. makarovi is slightly smaller than that of C. knipowitschii (Anistratenko 2013) though this feature is also slightly variable. Given the morphological similarity these differences may be considered as intraspecific variation. Moreover, unpublished genetic data suggest that recent populations of Clathrocaspia inhabiting the Dnieper-Bug estuary and determined as C. makarovi and C. knipowitschii belong to a single species (T. Wilke, pers. comm. 05 / 2020). Hence, we confirm the previous assumption of Wesselingh et al. (2019) and consider C. makarovi as a junior synonym of C. knipowitschii. As already discussed by Wesselingh et al. (2019), Clathrocaspia milae closely resembles C. knipowitschii. Boeters et al. (2015) distinguished the two species based on the degree of cover of the umbilicus, the shape of the peristome and the size and number of whorls of the protoconch. Most of these characteristics are found to be quite variable within populations of C. knipowitschii. Until molecular information is available we only tentatively list C. milae among the synonyms of C. knipowitschii. Moreover, while soft-body morphology of C. milae was described by Boeters et al. (2015), data on the anatomy of C. knipowitschii are not yet available. The concept of C. knipowitschii applied in the literature differs largely among authors. For example, C. knipowitschii sensu Logvinenko & Starobogatov (1969), who list the species among the Caspian Sea gastropods, is much broader than “ real ” C. knipowitschii; their illustration closely resembles C. brotzkajae, and we consider their record synonymous with that species (see also Remarks section of that species).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C856FFACFF3DFA64FECBA58E.taxon	distribution	Distribution and ecology (including C. makarovi). Restricted to the Azov-Black Sea Basin, where the species occurs in Taganrog bay, delta of the Don, Dnieper, Dniester, Danube rivers, estuaries and coastal lakes of NW part of the Black Sea Basin (Golikov & Starobogatov 1972; Anistratenko 2007 a; our data). Also known from Holocene deposits of the Danube Delta (Anistratenko & Prisjazhnjuk 1992) and offshore Crimea (in phaseoline silt; Golikov & Starobogatov 1966, 1972). In the Dnieper-Bug estuary, C. knipowitschii inhabits lotic waters of the Dnieper riverbed and its branches usually at a depth of 2 – 10 m. In 2015, a maximal population density of 4590 spec. / m ² and a and biomass of 7.73 g / m ² were measured in the Dnieper across from Kherson Hydrobiological Station on silty sand among the colonies of Dreissena at a depth of 2 m (Alexenko & Kucheryava 2019, T. Alexenko, pers. comm. 06 / 2020). Snails prefer substrates such as sand, silty sand, as well as the shells or shell fragments of bivalves and gastropods; in some localities in the Southern Bug snails occurred on stones at 1 m depth (Alexenko & Alexandrova 1987; Alexenko & Kucheryava 2019).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFE94FCEAA1E6.taxon	description	Fig. 13 e	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFE94FCEAA1E6.taxon	materials_examined	Type material. Holotype (ZIN 4438 / 1) and 18 paratypes (ZIN 4439 / 2 – 4443 / 6). Collected by S. A. Zernov in 15 / 08 – 15 / 09 / 1909, steamship “ Meotida ”. Type locality. Black Sea, offshore of Crimea near Alushta (Table 1, locality 29). The material comes from phaseoline silts, which typically contain reworked Neoeuxinian (Late Pleistocene) shells (Wesselingh et al. 2019). The preservation of the type material is typical for this kind of reworked material (pers. obs. F. P. W. 06 / 2020). Likely, the subspecies is an extinct Late Pleistocene lineage of C. knipowitschii. Other material. None.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFE94FCEAA1E6.taxon	description	Description. Slender shell with five low convex whorls. Shell surface poorly preserved, only traces of reticulate sculpture are visible. Aperture ovoid, adjoined, leaving no umbilicus. Base steep.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFE94FCEAA1E6.taxon	discussion	Remarks. Originally this taxon was described as the Black Sea’s fossil subspecies of Clathrocaspia gmelinii, but later Alexenko & Starobogatov (1987) considered it to belong as subspecies in Clathrocaspia makarovi, based on the co-occurrence of that species in the Azov-Black Sea Basin. Kantor & Sysoev (2006: 88) went a step further and listed aluschtensis as a synonym of makarovi. The holotype (Fig. 13 e), which is illustrated here for the first time, indeed shows a close resemblance to the type of Clathrocaspia makarovi (= knipowitschii; Fig. 13 f) but differs by a slightly more slender shell and more flattened whorls. Given the differences in morphology and stratigraphy, we consider aluschtensis as an extinct subspecies of C. knipowitschii that inhabited the Black Sea during the Holocene.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFE94FCEAA1E6.taxon	distribution	Distribution. Known only from the type locality / stratum.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFB3CFDE6A282.taxon	description	Fig. 14	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFB3CFDE6A282.taxon	description	C. [aspia] (Cl. [athrocaspia]) logvinenkoi (Gol. et St.) — Alexenko & Starobogatov 1987: 36.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFB3CFDE6A282.taxon	materials_examined	Type material. Holotype (ZIN 4489 / 1) and one paratype (ZIN 4490 / 2) collected by Mordukhay-Boltovskoj in 1937. Type locality. Delta of the Don River (Russia) (Table 1, locality 27). Other material. Three specimens collected in 2006 from the same region as the type locality (IZAN 2006.06.1 – 3; Anistratenko 2007 a).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFB3CFDE6A282.taxon	discussion	Remarks. A detailed description of the species was provided by Anistratenko (2007 a). The peculiar shell with broad conical shape, an occasional weak subsutural bulge and thickened peristome strongly suggest that it represents a distinct species. However, the paucity of material makes it difficult to assess whether it is only a local variety of C. knipowitschii.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85AFFACFF3DFB3CFDE6A282.taxon	distribution	Distribution. Known only from the type locality, where only two living individuals have ever been found (holotype and paratype). This species seems to prefer freshwater, since the salinity at the type locality fluctuates between freshwater and ca. 1 ‰ (Shokhin et al. 2006; V. V. A., unpublished data). It has never been mentioned from Holocene or any fossil deposits so far.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85DFFAAFF3DFC19FE2AA4DA.taxon	description	Fig. 12 a – h, m – p, r, s	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85DFFAAFF3DFC19FE2AA4DA.taxon	materials_examined	Type material. Lectotype (ZB-M W. Dyb. 104) and 67 paralectotypes (ZB-M W. Dyb. 5, 74, 104 and 105) (designated by Anistratenko et al. 2019). Type locality. “ Kaspi-See ” (Caspian Sea, without further details; Table 1, locality 26). Other material. 16 shells in ZIN collection of Starobogatov collected off Cheleken Peninsula (locality 16). In addition, a part of the type material of C. isseli (localities 14, 21) and Pyrgula sowinskyi (locality 24) belong to C. pallasii (see discussion under C. isseli and C. gmelini above). Also, the material includes several specimens from the Middle Caspian Basin (locality 9), labelled as “ paratypes ” of “ Caspia microcingulifera ”, an unavailable collection name coined by Starobogatov (ZIN, no number).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85DFFAAFF3DFC19FE2AA4DA.taxon	description	Description. Slender elongate shell, with 5 poorly convex, sometimes slightly stepped whorls. Protoconch large, bulbous, measuring c. 1.3 whorls and c. 420 – 430 µm in diameter (Fig. 12 o, p, r, s). Teleoconch sculpture consists of fine to prominent reticulum, whereas spiral keels are more prominent in most specimens. Last whorl comparably small, often compressed. Base low, aperture small and broadly ovoid, often laterally slightly expanded; umbilicus absent or very narrow.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85DFFAAFF3DFC19FE2AA4DA.taxon	discussion	Remarks. A certain variability in shell elongation, whorl convexity and sculpture expression is evident among the type series (Fig. 12 a – e). The typical features of C. pallasii are the slender elongate shell, the poorly convex whorl and the large, bulbous protoconch (Fig. 12 o, p, r, s), which distinguish the species from C. isseli and C. gmelinii. These typical features are also found in at least one paratype of P. sowinskyi (Fig. 12 m, n); this specimen is considered to belong in C. pallasii. Finally, the ZIN collection of Starobogatov contains a “ holotype ” and 12 “ paratypes ” of “ Caspia microcingulifera ”, an unavailable collection name. A part of the material, which was collected in the middle Caspian Sea (localities 6, 9), closely resembles Clathrocaspia pallasii (Fig. 12 f) and is referred to this species here. The so-called “ holotype ” and at least one of the “ paratypes ” do not belong to C. pallasii; they are discussed under the chapter dealing with doubtful names below.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85DFFAAFF3DFC19FE2AA4DA.taxon	distribution	Distribution. Endemic to the Caspian Sea, reported from water depths between 50 and 150 m (Logvinenko & Starobogatov 1969). Tarasov (1996 b) mentioned this species from 311 – 870 m. No living specimens of C. pallasii have ever been found.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85CFFAAFF3DFE20FACBA722.taxon	type_taxon	Type species. Caspia ulskii Clessin & W. Dybowski in W. Dybowski, 1887; by original designation. Caspian Sea, Recent.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85CFFA9FF3DFD43FB22A6D2.taxon	description	Fig. 15 a – d, f – i	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85CFFA9FF3DFD43FB22A6D2.taxon	materials_examined	Type material. Holotype (ZIN 4357 / 1) and five paratypes (ZIN # 9). Further 88 probable paratypes are listed in ZIN systematic catalogue (ZIN ## 2 – 8, 10 – 18), collected by B. M. Logvinenko in various parts of the Middle (ZIN ## 2 – 8) and South (ZIN ## 10 – 18) Caspian Sea between 26 / 06 / 1956 and 06 / 08 / 1957. Type locality. Caspian Sea off Apsheron Peninsula (Table 1, locality 15). The five paratypes studied herein come from the same locality; the other 88 probable paratypes derive from 16 different samples collected offshore Apsheron Peninsula, Kura delta and Cheleken Peninsula as well as in the northern part of the Middle Caspian Basin. Other material. One specimen from the Caspian Sea off Apsheron Peninsula (locality 15), labelled as “ paratype ” of “ Caspia turrita ”, an unavailable collection name coined by Starobogatov (ZIN, no number).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85CFFA9FF3DFD43FB22A6D2.taxon	description	Description. Small (up to 2.09 mm in height, 1.21 mm in width), slender shell with up to 4.5 low-convex, sometimes weakly stepped whorls. Protoconch unknown. Last whorl typically more bulgy than previous whorls. Aperture slender ovoid, poorly inclined, leaving wide umbilicus.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85CFFA9FF3DFD43FB22A6D2.taxon	discussion	Remarks. The holotype of U. schorygini (Fig. 15 a, b) shows a certain similarity to the lectotype of U. ulskii (Fig. 16 a), but it has a more elongated shell, a relatively lower and slightly projecting last whorl, a wide umbilicus and weakly convex whorls. These features are found — with some variability — also in the paratypes and distinguish the species from U. ulskii. However, that species is known for its highly variable shell, and U. schorygini might just be another morphological variety. Until there is clear evidence (genetic or morphological) that the two species cannot be separated, U. schorygini is maintained as a valid species. The ZIN collection of Starobogatov contains material from the Caspian Sea off Apsheron Peninsula (localities 14 and 15) labelled with the unavailable collection “ Caspia turrita ”, including a “ holotype ” and 18 “ paratypes ”. The “ holotype ” is not Caspiinae but a juvenile individual of a Pyrgulinae, perhaps a species of Caspiella (Fig. 15 e, j), while some “ paratypes ” are real Ulskia. At least one “ paratype ” (Fig. 15 c, d) resembles U. schorygini (which was collected from the same locality) concerning the conical shell and wide umbilicus and is tentatively referred to that species.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85CFFA9FF3DFD43FB22A6D2.taxon	distribution	Distribution. Middle and South basins of the Caspian Sea, from depths of 45 – 170 m.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85FFF96FF3DFC28FEB3A7BA.taxon	description	Figs 16, 17	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85FFF96FF3DFC28FEB3A7BA.taxon	materials_examined	Type material. Lectotype (ZB-M W. Dyb. 76) and 33 paralectotypes (ZB-M W. Dyb. 76 and 99) (designated by Anistratenko et al. 2019). The holotype of P. behningi (ZIN # 1) and 82 paratypes (ZIN ## 2 – 11) are listed in ZIN systematic catalogue, collected by B. M. Logvinenko in 26 / 06 / 1956 – 04 / 08 / 1957. As for P. nana, we found a specimen labelled as “ holotype ” in the Starobogatov collection (ZIN), as well as 13 probable paratypes. Type locality. “ Kaspi-See ” (Caspian Sea, without further details; Table 1, locality 26). Type locality of P. behningi: Western part of the South Caspian Sea in the vicinity of the Kura River mouth, 120 m (locality 23). The paratypes were collected off Apsheron Peninsula (Azerbaijan) (locality 14). Type locality of P. nana: western part of the Caspian Sea near Apsheron peninsula, 88 m (locality 15); the 13 probable paratypes were retrieved in the eastern part of the South Caspian Sea off Cheleken Peninsula, Turkmenistan (locality 20). Other material. The “ holotype ” and 6 “ paratypes ” of “ Caspia clessiniolaeformis ”, an unavailable collection name coined by Starobogatov (ZIN, no number), collected in 1957 and 1962 in the eastern part of the Middle Caspi-an Sea at a depth of 56 – 71 m (localities 5 and 17). Further three specimens labelled by Starobogatov as Caspia ulskii come from locality 17 (ZIN, no number), three from Selitrennoye (locality 1, RGM 1309810, 1309809, 1309856) and five specimens from the Kura delta (localities 25 d and 25 f, RGM 1310306 – 1310310).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85FFF96FF3DFC28FEB3A7BA.taxon	discussion	Remarks. The characteristic features of Ulskia ulskii are the small (up to 2.15 mm in height, 1.20 mm in width), slender and usually stepped shell with a tightly coiled aperture that rarely leaves an umbilicus (Fig. 16 a – z), a striated – wrinkled protoconch demarcated by a distinct but not particularly bulgy growth rim (Fig. 17 a – o) and a teleoconch microsculpture that consists of tiny, irregular, elongated beads (Fig. 17 b, c, f, i, k, m). Ulskia ulskii is a highly variable species with respect to shell shape. Neubauer et al. (2018) provided a detailed description for material from the Pleistocene of Russia (Fig. 16 t, v – z). These specimens are more elongate and slightly larger but otherwise fit well to the lectotype series of U. ulskii. Similarly, Holocene specimens from the Kura delta tend to be more slender and have a less stepped outline (Fig. 16 p – s, u), but the morphological variation is fluent and does not allow establishing clear species boundaries. Rather we consider all these differences to reflect intraspecific variation. The range of variation also covers the holotype of Pyrgula nana Logvinenko & Starobogatov, 1969 (Fig. 16 g, h) and P. behningi Logvinenko & Starobogatov, 1969 (Fig. 16 l – o), which closely resemble some of the paralectotypes of U. ulskii. We thus follow the previous opinion of Neubauer et al. (2018) and consider P. nana a junior synonym of U. ulskii; Pyrgula behningi is a new synonym of U. ulskii. Furthermore, we found in the ZIN collection of Starobogatov material labelled with the unavailable collection name “ Caspia clessiniolaeformis ”. The “ holotype ” and 6 “ paratypes ” of “ Caspia clessiniolaeformis ” collected in the eastern part of the Middle Caspian Sea fall in the morphological range of U. ulskii (Fig. 16 i, j).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C85FFF96FF3DFC28FEB3A7BA.taxon	distribution	Distribution. Endemic to the Caspian Sea, reported from water depths between 45 and 170 m (Logvinenko & Starobogatov 1969; data of ZIN catalogue). Tarasov (1996 b) mentioned the species from 478 m in the South Caspian Basin.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C860FF95FF3DFAC8FE24A58F.taxon	description	Fig. 18 i – m	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C860FF95FF3DFAC8FE24A58F.taxon	materials_examined	Type material. Holotype and 44 paratypes should be in the ZIN collection; despite major effort, none of the specimens could be located in this institution. One paratype, being a subadult specimen with partially destroyed aperture, was retrieved in the collection of the NMNH NASU (IKOFZ-It- 167). Type locality. Dnieper river near Kherson, Kherson region, Ukraine (Table 1, locality 30 a). The only retrieved paratype was collected from the Dnieper delta (locality 30 d). Other material. One specimen from the type locality, collected in 1982 by T. L. Alexenko and determined by her in cooperation with Ya. I. Starobogatov (UGSB 25237). One specimen from the late Holocene deposits of near Kiliya, Odessa region, Ukraine (IZAN unnumbered, locality 32).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C860FF95FF3DFAC8FE24A58F.taxon	discussion	Remarks. Alexenko & Starobogatov (1987) considered this species similar to the Caspian C. gmelinii, from which it is said to differ only in the more inflated whorls, the weaker sculpture and a slightly smaller shell. In combination with the measurements provided with the original description, C. stanislavi rather resembles the holotype of C. makarovi, which is present considered a synonym of C. knipowitschii. Thus, C. stanislavi is very likely too a synonym of C. knipowitschii, but a final decision requires investigation of the type material, foremost the holotype, and / or a genetic study once fresh material becomes available (Wesselingh et al. 2019). The species is treated as a taxon inquirendum.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C860FF95FF3DFAC8FE24A58F.taxon	distribution	Distribution. Endemic to the Black Sea Basin, known today only from the delta of the Dnieper River in the vicinity of Stanislav village and Dnieper-Bug liman (Ukraine). One shell was retrieved from late Holocene deposits of the Danube Delta.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C863FF94FF3DFEE1FD72A482.taxon	description	P. [yrgula] (Caspia) baeri [sic] valkanovi subsp. n. — Golikov & Starobogatov 1966: 354 – 355, fig. 1 (9).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C863FF94FF3DFEE1FD72A482.taxon	materials_examined	Type material. Holotype only (ZIN 4367 / 1). Type locality. Southern shore of Crimea, from phaseoline silts (Table 1, locality 28), probably reworked from Neoeuxinian (Late Pleistocene) strata (compare C. knipowitschii aluschtensis).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C863FF94FF3DFEE1FD72A482.taxon	discussion	Remarks. Originally this taxon was described (Golikov & Starobogatov 1966) as the Black Sea subspecies of Caspia baerii, but later Alexenko & Starobogatov (1987) considered it a separate species and so restricted C. baerii to the Caspian Sea. Records of C. valkanovi are known off the southern Crimean coast as (sub) fossil shells only. The holotype is poorly preserved and does not allow a proper assessment of identity and status. The general shape and size are indicative of the genus Clathrocaspia and traces of the reticulate sculpture can be seen under high magnification. The shell resembles closely the holotype of the subfossil subspecies C. knipowitschii aluschtensis retrieved from the same deposits (Fig. 13 e), and both might be synonyms. Furthermore, we are not entirely certain as to the stratigraphic age of the stratigraphic origin of this species. The phaseoline silt is a marine Holocene unit, which may contain reworked Late Pleistocene Neoeuxinian species (Wesselingh et al. 2019). Given the uncertainty related to the species’ identity and age, we treat this taxon as a nomen dubium.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C863FF94FF3DFEE1FD72A482.taxon	distribution	Distribution. Endemic to the Black Sea Basin.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF94FF3DFCC0FEC6A6ED.taxon	type_taxon	Type species. Rissoa caspia Eichwald, 1838; by subsequent designation (Logvinenko & Starobogatov 1969). Caspian Sea, Pleistocene (?).	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF94FF3DFC32FDFDA3D4.taxon	description	Fig. 19 f – h	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF94FF3DFC32FDFDA3D4.taxon	materials_examined	Type material. Kantor & Sysoev (2006: 99) stated that in ZIN no identified material of this species is found. We detected a lot in the ZIN collection of Starobogatov with six specimens and determined as “ Caspia derzhavini ”. Since this material is a single lot that was labelled by Starobogatov himself it is very likely the type material. Type locality. Caspian Sea, probably near Cheleken Peninsula (Table 1, locality 21). Other material. None.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF94FF3DFC32FDFDA3D4.taxon	discussion	Remarks. The shells of this species have a very slender elongate shape, and the protoconch ornamentation differs largely of that found in Caspiinae, showing irregular spiral threads on a smooth surface. Shape and protoconch features strongly remind of Laevicaspia (Neubauer et al. 2018). The small size and the short shell with only about five whorls suggest L. derzhavini is a juvenile Laevicaspia, and it might well be a synonym of a previously described Laevicaspia species. This problem cannot be properly solved from the material available for the species, which is why we consider L. derzhavini as a nomen dubium.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF94FF3DFC32FDFDA3D4.taxon	distribution	Distribution. Middle and South Caspian Sea, 45 – 81 m (Logvinenko & Starobogatov 1969). Tarasov (1996 b) mentioned the species from 311 – 870 m.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF93FF3DF92AFB38A4A6.taxon	description	Fig. 19 a – e	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF93FF3DF92AFB38A4A6.taxon	materials_examined	Type material. Holotype only (IZAN, unnumbered lot). Type locality. Drilling borehole 37 near Kiliya, south of Odessa region (Ukraine); Holocene sediments of Danube Delta (Table 1, locality 32). Other material. None.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF93FF3DF92AFB38A4A6.taxon	discussion	Remarks. This species was originally attributed to the genus Caspia due to its small size and shell outline. A restudy of the holotype of Caspia obventicia suggests reallocation of this species to the Pyrgulinae. The morphology strongly reminds of the genus Laevicaspia as recently revised by Neubauer et al. (2018). Laevicaspia obventicia is known only from the holotype, therefore further field studies are required to collect material and assure its validity and distinction from the highly variable L. lincta.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
03BF87A3C862FF93FF3DF92AFB38A4A6.taxon	distribution	Distribution. Only known in subfossil state from the type locality in the Danube Delta.	en	Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V., Wesselingh, Frank P. (2021): A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae). Zootaxa 4933 (2): 151-197, DOI: 10.11646/zootaxa.4933.2.1
