We present the first discovery of Late Paleozoic conodonts in Argentina, marking the southernmost occurrence of this fossil group in the dominantly cold, high latitudes of Gondwana. Recovered from the siliciclastic Río del Peñón (RDP) Formation at the Rincón Blanco section in the northern Precordillera, La Rioja Province, the fossil assemblage includes Neognathodus colombiensis and Neognathodus “pre-colombiensis,” precisely indicating the early Moscovian (late Atokan in North America) N. colombiensis Zone. Furthermore, the conodont fauna establishes a crucial temporal constraint for the brachiopod Tivertonia jachalensis–Streptorhynchus inaequiornatus (TS) Zone, which is a widely employed biostratigraphic unit in southern South America. The warm-water affinity of Neognathodus is in accordance with the record of typical paleoequatorial faunal elements in the TS Zone in several central western Argentinian basins, thus reinforcing the idea of a climatic amelioration in the southern latitudes of Gondwana during the early Moscovian.

中文翻译：

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阿根廷晚古生代牙形石的首次文献记录：冈瓦纳西南部晚古生代冰河期的生物地层学和古气候限制


我们在阿根廷首次发现了晚古生代牙形刺，标志着该化石群出现在寒冷的高纬度冈瓦纳古大陆的最南端。该化石组合是从拉里奥哈省普雷迪勒拉北部 Rincón Blanco 地段的硅质碎屑 Río del Peñón (RDP) 地层中发现的，其中包括 Neognathodus colombiensis 和 Neognathodus “pre-colombiensis”，准确地表明了早期莫斯科时期（北美晚期阿托坎时期） ) N. colombiensis 区。此外，牙形刺动物群为腕足动物 Tivertonia jachalensis-Streptorhynchus inaequioratus (TS) 区建立了关键的时间限制，该区是南美洲南部广泛使用的生物地层单位。新颌龙的温水亲和力与阿根廷中西部盆地TS区典型古赤道动物群的记录一致，从而强化了莫斯科早期冈瓦纳南纬地区气候改善的观点。