Ruthenica, 2006, 16(1-2): 89-91. ©Ruthenica, 2006

A new of the Held, 1837 (: : ) from Northwest Caucasus

Pavel V. KIJASHKO

Zoological Institute of Russian Academy of Sciences, Universitetskaya embankment, 1, Saint-Petersburg, 199034,

ABSTRACT. A new species Merdigera invisa Kijas- Mountains (Adygeja, Norhwest Caucasus). All of hko sp. nov. from the high-mountainous part of Nor- them were identified as a new species of Merdigera. thwest Caucasus is described. Taking into account the This species is described below. characters of this species, the diagnosis of the subfa- mily Merdigerinae Schileyko, 1984 is defined more exactly. Family Enidae Woodward, 1903 Subfamily Merdigerinae Schileyko, 1984 Genus Merdigera Held, 1837 Type species — Helix obscura Müller, 1774 There are discordant literature data on the dist- ribution of molluscs of the genus Merdigera Held, Merdigera invisa Kijashko, sp. nov. 1837 (type species — Helix obscura Müller, 1774) on Caucasus. A. Schileyko [1984] excludes Cauca- (Figs. 1 A, B, C) sus from the range of the sole representative of this genus, believing that «Multiple mentions about the Material. Northwest Caucasus, Adygeja, Lagonaki presence of the species “” obscura on Caucasus Mountains, southern foot of Lagonaki Ridge, right river- bank of Tsitse (right tributary of the river Psheha), (~ are due to the fact that the shell of this species is 1200 m above sea level), lime rocks. June 29, 2001; extremely similar to caucasian Akramovskiella um- coll. P.V. Kijashko (holotype and paratypes). Holotype brosa (Mousson, 1873)...» [Schileyko, 1984]. A. and 17 paratypes are stored in the Zoological Institute Kuznetsov [1999] published data that expanded the of Russian Academy of Sciences (St.-Petersburg, № 527- range of (Müller, 1774) from 2006). Europe eastward up to Dzungaria. Among other Diagnosis. The shell practically does not differ territories included into the range of this species, he from that of Merdigera obscura and Akramovskiella mentioned northwest Caucasus. However, molluscs umbrosa. Epiphallus approximately twice longer from Caucasian were not included in the list of than penis, without sharp flexures, flagellum very material studied by him. In the “Catalogue of mol- short. Border between penis and epiphallus not clear. luscs of Russia and adjacent countries” by Yu. Kan- Penis and penial appendix devoid inflations, verges tor and A. Sysoev [2005], the range of M. obscura and papillas, distal part of penis with thick walls, is given according to Kuznetsov. It includes Wes- proximal rather thin-walled, inner surface smooth, tern, Central and partially Southern Europe; Balkan with small blurred annular pillaster on border with Peninsula; northwest Africa; territories of Byelorus- epiphallus. Penial appendix weakly subdivided into sia (Vitebsk Region); Russia (the Tver, Smolensk, sections. A1 by its size and shape similar to proximal Yaroslavl regions, suburbs of St.-Petersburg and part of penis, inside with high annular pilaster on Moscow, northwest Caucasus); (mountain border between A1 and A2. A2 — thin-walled, ap- Crimea); Uzbekistan (western Tien Shan) and Ka- proximately twice as long as A1. Diverticle of sper- zakhstan (Dzungaria). Taking into account the pre- mathecal stalk reaching albuminous gland. Penial sence of Merdigera in Crimea, Central Asia and retractor with two branches standing apart immedi- Kazakhstan, molluscs of this genus undoubtedly ately near to male ducts, one branch attached to should live on Caucasus as well. However, I could proximal part of penis, another to middle of A1. not find information about specimens of Merdigera [Диагноз. Раковина практически не отличается от from Caucasus reliably identified by anatomic cha- Merdigera obscura и Akramovskiella umbrosa. Флагел- racters. люм очень короткий, иногда практически отсутствует. Эпифаллус примерно в два раза длиннее пениса, без In summer 2001, eighteen specimens of terrest- резких изгибов. Граница между пенисом и эпифаллу- rial molluscs similar to Merdigera obscura have сом не выражена. Пенис и пениальный аппендикс ли- been collected by me in the expedition to Lagonaki шены вздутий и папилл, дистальная часть пениса с