Boehme, Madelaine; Vasilyan, Davit; Winklhofer, Michael
Habitat tracking, range dynamics and palaeoclimatic significance of Eurasian giant salamanders (Cryptobranchidae) - indications for elevated Central Asian humidity during Cenozoic global warm periods.
In: Palaeogeography Palaeoclimatology Palaeoecology, Vol. 342: pp. 64-72
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Environmental fluctuations are a driving force in vertebrate evolution,but cryptobranchids (giant salamanders) show little morphologic changesince the Jurassic. Here we analyze their fossil distribution in theCenozoic of Eurasia and show that morphologic stasis is also maintainedby stable environments, making giant salamanders an ideal proxy-groupfor environmental and palaeoclimatic studies. The climate space ofrecent and fossil cryptobranchids is best characterized by high humiditywith mean annual precipitation values over 900 mm. The recordedpatchiness of their fossil record can be explained by habitat trackingand/or range expansion from higher altitudes into lowland settingsduring humid periods with increased basinal relief. In Central Asiacryptobranchids are recorded from five intervals, four of them areglobal warm periods: Paleocene-Eocene Thermal Maximum, Late Oligocenewarming, Miocene Climate Optimum, and Mio-Pliocene transition. Thisdistribution suggests that during global warmth the Asian cold highpressure zone during winter months may be weak or absent, thus moistwesterly winds penetrate far into the continent. The presence ofcryptobranchids also indicates that the aridification across theEocene-Oligocene boundary as reported from Mongolia and northwesternChina, does not occur in the Zaysan Basin, probably due to increasedupslope precipitation in the rising Altai Mountains.