Fig. 4 in Fig. 4 in Fig. 3 in Fig. 21. Sesarmops mora n in Paralbunea dayriti Author Jouladeh-Roudbar, Arash Department of Fisheries, Faculty of Natural Resources, University of Tehran, Karaj, Alborz, Iran. E-mail: jouladehroudbar @ ut. ac. ir jouladehroudbar@ut.ac.ir Author Ghanavi, Hamid Reza Department of Biology, Lund University, Lund, Sweden. * Correspondence: E-mail: hamid. ghanavi @ gmail. com (Ghanavi) hamid.ghanavi@gmail.com Author Doadrio, Ignacio Biodiversity and Evolutionary Biology Department, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain. E-mail: doadrio @ mncn. csic. es doadrio@mncn.csic.es text Zoological Studies 2020 2020-06-29 59 21 1 303 http://dx.doi.org/10.5281/zenodo.12822535 journal article 10.6620/ZS.2020.59-21 1810-522X PMC7807176 33456548 12822787 Acipenser nudiventris Lovetsky, 1828 – Native ( Fig. 18 ) Acipenser schypa Bonnaterre [ J. P. ] (ex Güldenstädt ) 1788: 16; Type locality: ‘ La mer du Nord’ (erroneous, is probably Caspian Sea ). Neotype : NRM 8946 (invalid). Acipenser nudiventris Lovetsky [A.] 1828: 78; Type locality: Aral Sea, Russia . No types known. Acipenser Eichwald schypa [C. E. von] 1831: 66; Type locality: Caspian Sea, unde Volga adscendit et Cyrum. Acipenser glaber Heckel [J. J.] (ex Fitzinger) in Fitzinger & Heckel 1836: 270; Type locality: Danube River, Austria . Syntypes :?NMW 91292 (1, dry). Acipenser nudiventris derjavini Borzenko [M. P.] 1950; Type locality: Kura River, Azerbaijan , Caspian Sea Region. Syntypes : (127) KVNIRO uncat. Common name : Pr: Ship, Tas mahi shekam brahne, Tas mahi, Mahi-ye kaviar, En: Ship Sturgeon, Bastard sturgeon. Diagnosis : Snout moderately long and pointed at tip. Mouth transverse and lower lip continuous, not interrupted at center. Barbels halfway between tip of snout and mouth, reaching the latter, no smaller plates between dorsal and ventral rows. Back is grey, flanks lighter, belly white. Meristic characters : D: 39–57, A: 23–37, GR: 24–45, DS: 11–17, LSC: 49–74, VS: 10–17, lost or absorbed in large adults. Distribution : Caspian Sea basin ( Fig. 19 ). In the past, the species was recorded from Kura and Aras Rivers, but it disappeared after the construction of a dam. According to Derzhavin (1934) and Armantrout (1980) , the species enters the Aras, Astara, Sefidrud, Tajan and Babol Rivers in Iran . See Acipenser gueldenstaedtii . Taxonomy . Conservation : IUCN: Critically Endangered A2cde (Gesner et al. 2010b).