铁杉属为松科的一类常绿乔木, 间断分布于东亚和北美温暖、湿润的生境中。本研究从内蒙古中部卓资县下中新统汉诺坝组中发现了铁杉属的3块球果化石和2块叶化石标本, 系首次从同一地区同一地层中同时发现这两种器官类型的铁杉属化石。对于立体保存的球果化石, 借助Micro-CT进行观察和扫描, 重建化石三维形态; 而对于叶压型化石, 则进行角质层分析以观察叶的微细结构特征。将化石与铁杉属的现生植物及相关化石种进行详细对比, 最终将3块球果化石鉴定为铁杉属新种卓资铁杉(Tsuga zhuoziensis sp. nov.), 2块叶化石鉴定为云南铁杉相似种(Tsuga cf. T. dumosa)。卓资铁杉在形态上与现生的云南铁杉(T. dumosa)最为接近, 表明二者亲缘关系较近。根据云南铁杉的气候分布以及在内蒙古卓资已报道的早中新世化石现生亲缘种分布区的气候数据, 推测内蒙古卓资早中新世的年均温比现在高约6—10℃, 年降雨量高出约700 mm, 表明卓资早中新世比现在更加温暖、湿润。结合前人在河北围场早中新世发现的铁杉属植物化石, 进一步推断华北地区早中新世的气候环境整体比现在更加温暖、湿润。

Tsuga Carr. is a genus of evergreen trees in Pinaceae, with disjunct distributions in warm, humid ecosystems between East Asia and North America. In this study, we describe three cones and two leaves of Tsuga collected from the Lower Miocene Hannuoba Formation in Zhuozi County, central Inner Mongolia, China. This report represents the first time that these two organs of Tsuga have been found from the same geological horizon and locality. The morphology of the three-dimensionally preserved cones was examined using Micro-CT scanning, while the microstructures of the leaves were studied via cuticle analysis. Through detailed comparisons with extant Tsuga species and other related fossil taxa, these three cone specimens are assigned to a new species, Tsuga zhuoziensis sp. nov., and the two leaves are assigned to Tsuga cf. T. dumosa. Morphologically, the new species is most similar to extant Tsuga dumosa, suggesting a close phylogenetic relationship. Based on the climate preferences of Tsuga dumosa and the climate data of previously reported Early Miocene fossil relatives from Zhuozi, it is inferred that the mean annual temperature during the Early Miocene in this region was approximately 6–10℃ higher than that of today, with annual precipitation exceeding 700 mm. This indicates that the Early Miocene paleoclimate of Zhuozi was significantly warmer and wetter than that of the present. In conjunction with Tsuga fossils from the Early Miocene of Weichang, Hebei Province, this study further supports the inference that North China experienced a warmer and more humid climate during the Early Miocene than today.

陕西省自然科学基础研究计划项目(2025JC-YBMS-272)、长安大学中央高校基本科研业务费专项资金(300102272206)和国家自然科学基金项目(41872017)联合资助