克罗地亚最深的洞穴中发现一种透明蜗牛

Scientists discovered a new species of a peculiar¹（独特的） cave-dwelling snail² in one of the 20 deepest cave systems in the world, Lukina Jama-Trojama in Croatia. The newly discovered species belongs to a genus of minute air-breathing land snails³ that have lost visual orientation⁴ and are considered to be true eutroglobionts, or exclusive cave-dwellers. The study describing the new species was published in the open access journal Subterranean⁵ Biology.   The new species Zospeum tholussum is a miniature and fragile snail, with a beautifully shaped dome-like translucent⁶（透明的） shell. Only one living specimen⁷ was found during the expedition around the galleries of the Lukina Jama-Trojama cave system. The animal was found at the remarkable⁸ depth of 980 m, in an unnamed chamber⁹ full of rocks and sand and a small stream running through it.   All known species from the cave-dwelling genus Zospeum possess a limited ability to move. Their preference of a muddy habitat and the fact that they are usually located near the drainage system of the cave, in a close proximity¹⁰ to running water, however suggest that these animals are not exactly immobile. Scientists hypothesize that dispersal is achieved through passive transportation via water or larger mammals.   The Lukina Jama-Trojama is the deepest cave system in Croatia, extraordinary for its vertical¹¹ shape, long pits and great depth of -1392 m. From an ecological¹² point of view this cave system is extremely interesting for having three microclimatic layers: firstly entrance icy part with the temperature of about 1 °C, secondly¹³, middle part with the temperature up to 2 °C and bottom part with temperature till 4 °C. These unusual living conditions make the cave extremely interesting for scientist from a biodiversity point of view.