Corbicula elatior, VON MARTENS, 1905

Bespalaya, Yulia V., Kropotin, Alexander V., Kondakov, Alexander V., Aksenova, Olga V., Gofarov, Mikhail Yu., Kim, Sang Ki, Lee, Jin Hee, Travina, Oksana V., Vikhrev, Ilya V., Vinarski, Maxim V. & Bolotov, Ivan N., 2023, A taxonomic reassessment of native and invasive species of Corbicula clams (Bivalvia: Cyrenidae) from the Russian Far East and Korea, Zoological Journal of the Linnean Society 197 (1), pp. 104-126 : 116-119

CORBICULA ELATIOR VON MARTENS, 1905

Corbicula elatior von Martens, 1905: 65 , pl. 2, fig. 5 ( Korea, Kyongsang-namdo and Kyonggi-do provinces)

= Corbicula suifuensis Lindholm, 1925: 29 [ Russia, Primorye Region, Suifun (nowadays Razdolnaya) River near Razdolnoye settlement]

= Corbicula amurensis Bogatov & Starobogatov, 1994: 149 , fig. 1D–F ( Russia, Khabarovsk Region, the Lower Amur river near Balbinskiy Cliff, 22 km upstream of Kalinovka settlement and 337 km from the mouth), synon. nov.

= Corbicula neƲelskoyi Bogatov & Starobogatov, 1994: 148–149 , fig. 1A–C ( Russia, Khabarovsk Region, the Lower Amur River near Balbinskiy Cliff, 22 km upstream of Kalinovka settlement and 337 km from the mouth), synon. nov.

= Corbicula sirotskii Bogatov & Starobogatov, 1994: 149 , fig. 1G–I ( Russia, Khabarovsk Region, Lower Amur River, 7 km upstream of Maxim Gorky settlement and 397 km from the mouth), synon. nov.

Type material: The lectotype [a pair of valves; ‘ Corbicula elatior Marts. , Naktonggang’; designated by Glaubrecht et al., 2007], ZMB 55.624 ; paralectotypes ZMB 38.439 (ten pairs of valves, one right valve; ‘ Corbicula elatior jung, Naktonggang , mittl. Arm Korea, Gottsche’) ; paralectotypes ZMB 38.429 (six pairs of valves, one right valve; ‘ Corbicula No. 1, N’aktonggang, Gottsche’ ) ; paralectotypes ZMB 38.430 b (three pairs of valves, one tiny right valve; ‘ Corbicula no. 2, Imjingang bei Imjin 20/9 Gottsche’); paralectotype ZMB 55.626 (a pair of valves; specimen depicted in Fig. 6 as ‘ C. elatior ?’) ( Glaubrecht et al., 2007).

Type locality: ‘ Mittlerer Arm des Naktonggang, Hauptfluss der Provinz Kyöngsangdo, zwischen Tongnai und Kimhai. Imjingang bei Imjin, Provinz Kyöngkwido, Korea’; South Korea: restricted to Naktong River near Kimhae, Kyongsang-namdo (NakdongRivernearGimhae, Gyeongsangnam Prov., 35°11 ′ 57 ″ N, 128°54 ′ 00 ″ E). Locality of paralectotypes: Prov. Kyonggi-do: Imjin River near Imjin ( Glaubrecht et al., 2007) .

Material examined: The type series. Our samples: Far East of Russia: lower reaches of the Lower Amur River near Nikolaevsk-on-Amur City, 53°7 ′ 12.948 ″ N, 140°50 ′ 47.646E ″, 17 July 2014, 28 specimens, Bolotov I.N. & Vikhrev I. V. leg. (lot nos RMBH Corb 15); Nizhnetambovskoe settlement, 16 September 2020, 50.952778N, 138.204444E , 89 specimens, Aksenova O. V., Kropotin A. V., Travina O. V. & Vinarski M. V. leg .; 61 specimens are stored in RMBH ; 28 specimens from the same locality are kept in LMBI under accession number 21-044; Nizhnetambovskoe settlement, 7 July 2021, 50.921111N, 138.1775E , 23 specimens, Aksenova O. V., Kropotin A. V., Travina O. V. & Khrebtova I.S. leg. ; one specimen from Razdolnaya River is kept in ZIN collection, accession number 3 .

Description: The shell is large, triangular, and the ventral margin is rounded ( Fig. 6 ). The umbo issignificantly prominent and slightly offset. Sculpture is represented by well-marked deep concentric ridges; the width of the ribs and distance between them are variable in the same specimen. External shell coloration varies from dark brown, greenish brown to yellow–brown, sometimes with light or dark concentric bands. Internal shell coloration varies from matte white with pale violet marks to light purple. Hinge has a heterodont dentition type, with three cardinal teeth on each valve and two crenulated lateral teeth. Siphons conical, both narrow, with a row of short papillae. Black pigment is concentrated in rings internally at the base of both siphons and in the edge of the mantle forming the siphons. The outer surface of the siphons is white; on the inside, the siphons are bright orange. The papillae of both siphons are without dark rings. Corbicula elatior is dioecious.

Differential diagnosis: This species could be distinguished from the sympatric Corbicula leana , C. f l u m i n e a a n d C. j a p o n i c a b y t h e f o l l o w i n g combination of characters: larger size, significantly prominent umbo, well-marked deep concentric ridges, external shell with light or dark concentric bands, the siphons without dark pigmentation and with short papillae.

Distribution: East Asia: Amur River and the Korean Peninsula ( Graf & Cummings, 2021). The records of this species in the South Primorye Region (Razdolnaya River) and China (Itunghe River) ( Zatravkin & Bogatov, 1987) need to be checked.

Comments: Considering that the samples from the Lower Amur River are genetically identical to the samples from the Seomjin River ( South Korea) collected by Park & Kim (2003), we also analysed the original descriptions of some nominal species described from South Korea: C. producta , C. elatior , C. colorata and C. papyracea . Presumably, C. producta is a junior synonym of C. fluminea (for details, see Discussion). According to their original descriptions ( Heude, 1887; von Martens, 1905), C. colorata and C. papyracea are small clams with a flattened umbo. At the same time, the specimens of Corbicula from the Lower Amur River are distinguished by a relatively large shell and prominent umbo. We were unable to find any significant conchological differences between our samples of Corbicula from the Lower Amur and the type specimens of nominal species described by Bogatov & Starobogatov (1994) ( Figs 6 , 7 ). The original morphological description of C. elatior published by von Martens (1905) ( Fig. 7E ) corresponds well to the morphological features of our samples from the Lower Amur River. Hence, we assume that C. elatior represents a species endemic to the Far East of Russia and the Korean Peninsula. The nominal species C. amurensis , C. neƲelskoyi and C. sirotskii are considered here junior synonyms of C. elatior .

Figures

Figure 6. Morphology and anatomy of Corbicula elatior from the Khabarovsk Region (Russia). A, variability in shells of Corbicula samples from the lower course of the Amur River near the Nizhnetambovskoe settlement. B, young individuals of C. elatior from the Amur River near the Nizhnetambovskoe settlement. C, Amur River near the Nizhnetambovskoe settlement. D, morphology and anatomy of Corbicula elatior Martens, 1905 from the Lower Amur River (lot no. RMBH Corb 0015/3). E, gills. F, longitudinal section of the siphon. G, outgrowths on the mantle edge on the different part of mantle.

Figure 7. Samples of Corbicula elatiorfrom museum collections.A,holotype ofCorbicula amurensisBogatov & Starobogatov, 1994 with its labels: ZIN; Russia, Khabarovsk Region, lower course of the Amur River. B, holotype of Corbicula sirotskii Bogatov & Starobogatov, 1994 with its labels: ZIN; Russia, the lower course of the Amur River. C, holotype of Corbicula neƲelskoyi Bogatov & Starobogatov, 1994 with its labels: ZIN; Russia, the lower course of the Amur River. D, samples of C. elatior from the Razdolnaya River (ZIN RAS No. 3, 18/08/1928, A. Derzhavin leg.). E, lectotype of Corbicula elatior Martens, 1905 with its labels: ZMB, No. 55624: Nakdong River near Gimhae, Gyeongsangnam Prov. Scale bars: 2 mm in A–C, E; 5 mm in D. Photographs: M. V. Vinarski.