Callistocythere hosonosuensis Okubo, 1979

Ji, Su-Jung, Jung, Chuleui, Bang, Hyun Woo, Song, Min Ok, Jung, Jongwoo, Yoon, Seong Myeong, Lee, Seunghwan, Keum, Seoyoung, Yang, Hee-Min, Lee, Dongmin, Lee, Geon Hyeok, Oh, Jaeseok, Kim, Kichoon, Park, Hansol, Moon, Heejin, Joharchi, Omid, Kang, Yeseul, Eom, Keeseon S., Lee, Kyung Jin, Eun, Ye, Kim, Taeho, Karanovic, Ivana, Lee, Jeounghee, Choe, Seongjun & Min, Gi-Sik, 2023, Unrecorded species of Korean invertebrates discovered through the project of ‘ Discovery of Korean Indigenous Species’ II, Journal of Species Research 12 (1), pp. 68-89 : 83

33. Callistocythere hosonosuensis Okubo, 1979 ( Fig. 33 )

ŀğŅPḄḤṆḇNj (ṵAE)

Material examined. Bongam-ri (34°59.629′N, 128° 26.198′E), Gyeongsangnam-do, Korea; with plankton net; collected by I Karanovic on 31 March 2013 .

Deposition. NIBRIV0000835137.

World distribution. Japan and Korea.

Diagnosis. Size about 1 mm. Shell thick (strongly calcified) and laterally compressed. Surface covered with relatively large subdivided (in several) pits. Dorsal margin inclined towards posterior end with greatest height situated frontally. Anterior margin broadly rounded, posterior margin narrower, ventral margin concave around middle length. Radial pore canals poly-furcated anteriorly and posteriorly. Hingement consisting of two anterior terminal teeth on the left valve and two corresponding sockets on the right valve. Hemipenis with anterior process of right-angled triangular lamella with prominent concave hypotenuse; middle process of tongue-like lamella; posterior process of curved bottle-shaped tube with broadened end.

Remarks. This species resembles C. hayamensis Hanai, 1957 and C. angulata Okubo, 1979 but differs from both in the general outline and shell sculpturing, and most of all in the morphology of hemipenis, especially the bottle-shaped posterior process.

Figures

Fig. 33. Hemipenis of Callistocythere hosonosuensis Okubo, 1979. A. right valve; B. hemipenis.