In this article, we report on two proboscidean upper tusks from a new locality in Iran, Kivi-1 (KIV). The tusks are oval to circular in cross-section, lack an enamel band, are strongly curved and double-twisted, and turn inwards at the tip. This morphology permits the attribution to Choerolophodon, an elephantimorph proboscidean well distributed during the Miocene in the Old World and already known from the late Miocene of Iran. Although the known upper tusks of Choerolophodon are few, the current data indicate that the curvature of the upper tusks may have biostratigraphic significance: in earlier and more primitive representatives from the early and middle Miocene of Eurasia, the curvature is less pronounced, whereas in the later and more derived ones from the late Miocene, it is strong. Based on this feature, we propose that the horizons from which these tusks derive date to the upper Miocene. During this epoch, two choerolophodont species were present in the Greco-Iranian palaeobiogeographic province, C. anatolicus and C. pentelici, the latter one well represented in the nearby Maragheh faunas. Because more diagnostic specimens are so far lacking, we attribute the KIV specimens to Choerolophodon sp. indet. “derived morph”. Based on the presence of either C. anatolicus or C. pentelici in KIV, a relatively open palaeoenvironment is assumed, in agreement with previous palaeoecological reconstructions from the wider region during this period.

中文翻译：

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来自上中新世新地方的Choerolophodon（Proboscidea，哺乳动物）：Kivi-1（伊朗）

在本文中，我们报告了来自伊朗一个新地区Kivi-1（KIV）的两个长喙象牙。牙的横截面为椭圆形到圆形，没有牙釉质带，弯曲强烈且扭曲了两次，并在尖端向内弯曲。这种形态可以归因于Choerolophodon，这是一种象形的长喙类，分布在旧世界的中新世时期，从伊朗的中新世就已经知道了。虽然已知的choerolophodon的上upper牙很少，当前数据表明上牙的曲率可能具有生物地层学意义：在较早和较原始的欧亚大陆中新世早期和中期代表中，曲率较不明显，而在较晚和较衍生自欧亚大陆的中生代中中新世晚期，很结实。基于此特征，我们建议这些牙从中得出的地层要追溯到上中新世。在这一时期，希腊-古古生物地理省C出现了两种变色龙物种。anatolicus和Ç。pentelici，后者在附近的马拉格（Maragheh）动物群中有很好的表现。由于到目前为止缺少更多的诊断标本，因此我们将KIV标本归因于霍乱恐怖菌 indet。“派生变体”。基于两个C的存在。anatolicus或Ç。在KIV的pentelici中，假定在此期间相对开放的古环境与先前从更广阔的地区进行的古生态重建相一致。