Gastropoda, Pulmonata, Helicidae)
Total Page：16
File Type：pdf, Size：1020Kb
Ruthenica, 2012, vol. 22, No. 2: 93-100. © Ruthenica, 2012 Published October 20, 2012 http: www.ruthenica.com On the origin of Cochlopupa (= Cylindrus auct.) obtusa (Gastropoda, Pulmonata, Helicidae) Anatoly A. SCHILEYKO A.N. Severtzov Institute of Ecology and Evolution of Russian Academy of Sciences, Leninsky Prospect 33, 119071, Moscow, RUSSIA; e-mail: [email protected] ABSTRACT. Land snail Cochlopupa obtusa (Drapar- py) is widely-used for the species of Helicidae dur- naud, 1805) is an endemic of Eastern Alps. The mol- ing many tens of years. Unfortunately, this name is lusk has very unusual for helicids pupilloid shell, but invalid because it is junior homonym of Cylindrus its reproductive tract is quite typical for the subfamily Batsch, 1789 (Gastropoda, Conidae) (type species Ariantinae (Helicidae). Neither this species nor any Conus textile Linnaeus, 1758, by subsequent desig- similar forms are totally absent in fossil deposits (the nation Dubois and Bour, 2010). earliest records of C. obtusa conventionally dated by the “pre-Pleistocene”). According to suggested hy- At the same time the generic name Cylindrus pothesis, this species is very young and was formed Fitzinger is a junior objective synonym of Cochlo- within the existing area at the end of Würm glaciation pupa Jan, 1830 with type species Pupa obtusa due to mutation of some representative of Ariantinae. Draparnaud, 1805 (by monotypy). Thus, the correct binomen for the representative of Helicidae in ac- cordance with the rules of the ICZN must be Coch- Introduction lopupa obtusa (Draparnaud, 1805). Some years ago I have written that I directed a In Eastern Alps, on the territory of Austria, lives petition to the International Commission on Zoo- a very peculiar species of the Helicidae family – logical Nomenclature where I ask to conserve the Cochlopupa obtusa (Draparnaud, 1805) (Fig. 1A). name by Fitzinger [Schileyko, 2006: 1786]. In fact, Externally this species is so drastically differs from at that time I did not send the petition (for reasons all other Helicidae, that it has been separated in not related to the case), but it is now evident that the independent genus constituting a separate mono- petition is not necessary. typic tribe Cylindruini [Schileyko, 2006]. At the So, formally the position of the genus and spe- same time, anatomical features clearly indicate that cies is follow: this species undoubtedly belongs to the Helicidae family [Martens, 1895; Sturany, Wagner, 1914; Schi- Fam. Helicidae Rafinesque, 1815 leyko, 1996] (Fig. 1B). This species is so strange that Adensamer [1937: 100] conventionally called Subfam. Ariantinae Mörch, 1864 the species “living fossil” (“lebendes Fossil”), al- though he himself understood that this term in the Genus Cochlopupa Jan, 1830 given case is not correct. Jan, 1830: 5 (Pupa subgen.); The peculiarity of Cochlopupa obtusa area is Cylindrus Fitzinger, 1833: 107, type species – Pupa obtusa that the snails live at altitudes of 1600-2500 m Draparnaud, 1805, by monotypy; nom. praeocc., non above sea level and is presented by 150 fully isolat- Batsch, 1789 (Gastropoda, Conidae). ed colonies (or groups of colonies) [Bisenberger et Type species – Pupa obtusa Draparnaud, 1805, al., 1999; Klemm, 1961, 1974] (Fig. 2). Backhuys by monotypy. [1969] names such a phenomenon “elevation ef- fect”. It is essential, that the animals conduct a Discussion: facts and interpretations secretive mode of life (they inhabit limestone rock slides) and have very limited individual activity. To understand the reasons of appearance of such The purpose of this publication is the analysis of an unusual shell of Cochlopupa obtusa and the the facts concerning the possible ways and time of formation of such a peculiar area, we must answer origin of this peculiar species. four somewhat interrelated questions: 1. How could On the generic name be formed such a peculiar area? 2. Where the spe- cies has originated? 3. Who could be an ancestor of The generic name Cylindrus Fitzinger, 1833 (type this species? 4. When the species could appear (i.e. species Pupa obtusa Draparnaud, 1805 by monoty- geological age of the species)? 94 A. A. Schileyko FIG. 1. Cochlopupa obtusa from Sengsengebirge, Hocher Nock, Haltersitz, 30 July, 2009. A – shell. B – reproductive tract and open penis. AG – albumen gland; DS – diverticle of spermathecal stalk; F – flagellum; MG – mucus gland; P – penis; PP – papilla of penis; PR – penial retractor; RS – reservoir of spermatheca; St – stylophore. РИС. 1. Cochlopupa obtusa из Зенгзенгебирге, Хохер Нок, Хальтерзитц, 30 июля 2009. А – раковина. В – репродуктив- ный тракт и вскрытый пенис. AG – белковая железа; DS – дивертикул протока семеприемника; F – флагеллум (бич); MG – слизистая железа; P – пенис; PP – папилла пениса; PR – ретрактор пениса; RS – резервуар семеприемника; St – стилофор. 1. Way of formation of the Cochlopupa 1909], but the fate of Cochlopupa obtusa is reason- area ably traced only after the very last and the most powerful glaciation (Würm), which ended, on geo- To answer the first question (taking into account logical scale, quite recently – just 10-12 thousand the characteristics of the area), it is appropriate to years ago. search among external factors, primarily the geo- The analyses of microfossilized plant pollens logical history of the Eastern Alps, (in particular, found in geological deposits, has chronicled the the history of climate and glaciations), and the dramatic changes in the European environment dur- presence of suitable (calcified) soil. ing the Würm glaciation. During the height of this Since the Oligocene, Mediterranean geosyncli- glaciation, ca 24,000-10,000 years ago, significant nal area has undergone intensive folding (Alpine part of the territory of Austrian Alps (except for the orogeny). Actually the Alps as a mountain system easternmost parts) was covered with thick ice fields emerged in the upper Miocene, i.e. about 10 million [van Husen, 1987] (Fig. 2). Thus, all Recent mala- years ago [Popov et al., 2009], but what is known cofauna of Eastern Alps arose due to invasion from about malacofauna of the Eastern Alps before the adjacent territories or from some refugia within last glacial time, does not contribute to understanding 10-12 thousand years [Ložek, 1982], since, I am the history of the species and its area. As said repeating, at the time of Würmian glaciation most above, there are serious reasons to believe that the of surface of Eastern Alps (except for easternmost formation of the Cochlopupa area is connected, in parts) has been covered with ice shield. Herbert Ant particular, with glaciations. [1969: 249] writes that “Keineswegs ist aber die In total, during the Holocene 4 glacial periods Annahme berechtight, dass es im Sinne einer Tabu- took place in the Eastern Alps [Penck, Brückner, la-rasa-Theorie zur völligen Auslöschung gekom- On the origin of Cochlopupa obtusa 95 FIG. 2. Localities of Cochlopupa obtusa [after Klemm, 1973] superimposed on the map of Würm glaciation in Eastern Alps [after van Husen, 1987]. Asterisk – Vienna. Square – Klagenfurt. Circle – Innsbruck. Triangle – Salzburg. Thick line indicates the border of Austria. РИС. 2. Места находок Cochlopupa obtusa [из: Klemm, 1973], наложенные на карту Вюрмского оледенения в Восточных Альпах [по: van Husen, 1987]. Звёздочка – Вена. Квадрат – Клагенфурт. Кружок – Инсбрук. Треугольник – Зальц- бург. Толстая линия обозначает границу Австрии. men ist” (“by no means is reasonable to assume that climate the lace of Cochlopupa area is gradually in terms of tabula rasa theory it [fauna] has come to becoming increasingly sparse due to the extinction of the complete obliteration”); nevertheless we must populations which inhabited the lower parts of slopes, accept the fact that the elements of malacofauna are i.e., figuratively speaking, the snails were raised fol- preserved only at the margins of the ice fields, and lowing the snow line, and the area eventually ac- among these elements Cochlopupa obtusa has ne- quired the modern appearance. I would like to remind ver been found. and underline once more, that, judging from actual Thus, I see two possibilities to explain the pres- situation, ancestors of Cochlopupa obtusa, whoever ence of the species in the Eastern Alps and peculiar- they were, lived in rather cold places. ities of its range: either snails migrated from some- Taking into consideration mode of life of Co- where, or the species appeared here. Since nothing chlopupa (secretive, little active), random dispersal like Cochlopupa in Europe is absent and apparently ways, such as passive migrations of snails from one never was, I am inclined to assume that the second isolated mountain to another by wind, birds, large way is the only possible one, and Cochlopupa ob- flying insects, etc., could theoretically occur, but tusa originated in situ. the likelihood of such events is extremely low. More- Based on the above, I propose a hypothesis that, over, such events, considering the number of colo- in my opinion, could explain the formation of such nies of Cochlopupa obtusa, must have been repeat- a kind of area. ed often enough (at least 149 times); this circum- At the end of the Würm glaciation, 10-12 thou- stance additionally lowers the probability of pas- sand years ago, when glaciers began to melt rapidly, sive dispersal of the snails. the climate of the East-Alpine region was still cool, Finally, we must also bear in mind that these and this cold-loving species has been widespread snails live almost everywhere (at these altitudes) over the discussed territory. During subsequent where there is limestone. This may indicate either a warming of climate the populations lived in the high dispersal capacity of the species or that its valleys of the Eastern Alps, got in adverse condi- initial distribution was much less sparse (almost tions and become extinct; with further warming of unbroken). Taking into account the above, I am 96 A. A. Schileyko definitely inclined to the second supposition. Oth- phenomenon: the most glaring example – muta- erwise, it turns out that as soon as somewhere ap- tions in the direction of whorls coiling.