Stratigraphical distribution of the Ordovician conodont Erraticodon Dzik in Argentina

• The conodont Erraticodon Dzik is studied from Ordovician outcrops from Argentina.
• Erraticodon patu is recorded in Floian-Dapingian deposits in North Western Argentina.
• Erraticodon hexianenesis from the Lenodus variabilis and Yangtzeplacognathus crassus zones in the Precordillera.
• E. cf. Erraticodon balticus from the L. variabilis to Eoplacognathus pseudoplanus zones (Precordillera).
• We propose use these species as biostratigraphic tools.

Three different species of the Ordovician genus Erraticodon Dzik are described and illustrated. Erraticodon patu Cooper is reported from the Lower–Midde Ordovician strata of the Acoite and Alto del Cóndor formations. E. cf. Erraticodon balticus and Erraticodon hexianensis from Middle Ordovician carbonate deposits of the San Juan Formation are analyzed and compared to specimens of these species from Australia, China, Newfoundland, and Baltica. E. patu and E. hexianensis are recorded for first time in the San Juan Formation of Precordillera. The elements of E. cf. E. balticus resemble closely E. balticus Dzik but lack the important denticle on the posterior process of the S elements. An evaluation of the stratigraphic occurrences of these species relative to those of key Lower and Middle Ordovician conodont species such as Trapezognathus diprion Lindström, Oepikodus intermedius Serpagli, Baltoniodus triangularis (Lindström), Baltoniodus navis Lindström, Yangtzeplacognathus crassus (Chen and Zhang) and Eoplacognathus pseudoplanus (Viira) indicates they value for biostratigraphic correlation.

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