Ectothermic vertebrates (Actinopterygii, Allocaudata, Urodela, Anura, Crocodylia, Squamata) from the Miocene of Sandelzhausen (Germany, Bavaria) and their implications for environment reconstruction and palaeoclimate
Ectothermic vertebrates (Actinopterygii, Allocaudata, Urodela, Anura, Crocodylia, Squamata) from the Miocene of Sandelzhausen (Germany, Bavaria) and their implications for environment reconstruction and palaeoclimate
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DOI：
10.1007/s12542-010-0050-4
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发表时间：
2010-03-01
影响因子：
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通讯作者：
Boehme, Madelaine
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作者：
Boehme, Madelaine
早至中新世化石所在地桑德尔斯豪森已经产生了48种外温脊椎动物，因此代表了中新世最多样化的外温动物群之一。鱼类、两栖动物和爬行动物的35个分类群，其中包括3个新种：Pelobates fahlbuschi nov.SP.(Pelobatidae，最丰富的脊椎动物)、巴伐利乌斯(Tropidophorus bavaricus nov.)SP.(Lygoominae)和Bavaricordylus molassicus nov.SP.(Cordylidae)，并对其进行了描述。另外还有三个种是新种，但还没有命名：林蛙科。11月将军。Et sp.，AnGuidae Gen.INTER.SP.11月和Palaeobanus sp.11月(双鱼科)。为了恢复古环境和过去的水文条件，引入了一种新的方法(牙齿替换法，TRM)，该方法可以检测淡水鱼Taphocoenose中的原生成分。TRM在上淡水莫拉塞的45个地点进行了测试，给出了合理的结果，与其他分析方法一致。因此，它被认为是区分桑德尔豪森地区常年和季节性水状况的可靠方法。利用TRM分析表明，三德尔豪森古水文具有从临时水到永久水的变化特征。在临时水条件期间(单位B至单位D，下部)，生态系统受到季节性洪水的驱动，剩余的河岸水池没有产生原生鱼类种群，而是两栖动物的产卵地(两栖水池)。根据赤眼蜂的绝对优势，建议在干旱季节在沙质和不受地下水影响的土壤附近建立一个基本开放的栖息地。SP.由于河岸池塘类型的永久水条件的建立，该生态系统改变了上部(单元D1的后期和单元D2和E)，保留了原生的古Caraecarassius/Channa鱼类种群(鱼塘)。重建的降雨值表明，观测到的水文条件的变化可能是由气候驱动的。剖面下部为半干旱/半湿润区，年平均降水量为571 mm，上部为亚湿/湿润区，年平均降水量为847 mm。降水量增加约280毫米可能是由于在D2和E单元期间，降水季节较少，伴随着区域地下水位较高，根据几种嗜热爬行动物的出现，并与古植物学和氧同位素数据一致，桑德尔豪森的气候被解释为副热带气候，年平均温度从18A摄氏度到20.8A摄氏度，平均冷月温度从12.6A摄氏度到13.3A摄氏度，平均暖月气温从25.1A摄氏度到28.1A摄氏度。
The Early to Middle Miocene fossil locality Sandelzhausen has yielded 48 species of ectothermic vertebrates and thus represents one of the most diverse ectotherm faunas of Miocene age. Thirty-five taxa of fishes, amphibians and reptiles, including three new species: Pelobates fahlbuschi nov. sp. (Pelobatidae, the most abundant vertebrate), Tropidophorus bavaricus nov. sp. (Lygosominae) and Bavaricordylus molassicus nov. sp. (Cordylidae), are described. Three additional species are new, but are not named yet: Ranidae indet. nov. gen. et sp., Anguidae gen. indet. sp. nov. and Palaeoblanus sp. nov. (Amphisbaenidae). In order to reconstruct the palaeoenvironment and past hydrologic conditions, a new methodology (the tooth replacement method, TRM) is introduced, which allows for the detection of autochthonous components within freshwater fish taphocoenose. TRM is tested on 45 localities from the Upper Freshwater Molasse and gives reasonable results in agreement with other analytical approaches. It is therefore viewed as a reliable method to distinguish perennial from seasonal water conditions at the Sandelzhausen locality. Using the TRM it was demonstrated that the palaeohydrology of Sandelzhausen is characterized by a change from temporary water to permanent water conditions. During the period of temporary water conditions (units B to D1, lower part) the ecosystem was driven by seasonal inundations, and the remaining riparian pools have yielded no autochthonous fish population, but acted as spawning places for amphibians (amphibian pool). A mostly open habitat in the close vicinity, with sandy and non-groundwater-affected soils during the dry season, is suggested based on the absolute dominance of the spadefoot Pelobates fahlbuschi nov. sp. This ecosystem changed up-section (late part of unit D1 and during D2 and E) due to the establishment of permanent water conditions of riparian pond type, preserving an autochthonous Palaeocarassius/Channa fish population (fish pond). The reconstructed precipitation values suggest that the observed change in hydrologic conditions was probably driven by climate. The lower part of the section gives semi-arid/sub-humid values, with 571 mm mean annual precipitation (MAP), whereas the upper part yields sub-humid/humid values of 847 mm MAP. The increase in precipitation by about 280 mm was perhaps caused by a less seasonal precipitation regime with concomitant higher regional groundwater tables during units D2 and E. Based on the occurrence of several thermophilous reptile species, and in agreement with palaeobotanical and oxygen isotope data, the climate of Sandelzhausen is interpreted as subtropical with mean annual temperatures from 18A degrees C to 20.8A degrees C, mean cold month temperatures from 12.6A degrees C to 13.3A degrees C and mean warm month temperatures from 25.1A degrees C to 28.1A degrees C.