North American Spathian (upper Olenekian, Lower Triassic) neogondolellin conodonts

AbstractThe taxonomy and biostratigraphy of poorly known neogondolellin conodonts from mostly Spathian (upper Olenekian, Lower Triassic) strata are described from widespread localities in North America: high latitude Canadian Arctic, mid‐latitude British Columbia (BC), and lower latitudes in the USA. The occurrence of the neogondolellins in key sections and in matrix of dated ammonoid collections is documented. Neogondolellins characteristic of seven ammonoid zones are identified. Fifteen new conodont species are assigned to four genera:Borinella,Columbitella,MagnigondolellaandNeogondolella.Borinella, more common in the Smithian, undergoes a radiation in the early Spathian ‘tirolitid n. gen. A’ ammonoid beds of California eventually resulting in five newNeogondolellaspecies (Ng. bucheri,Ng. darwinensis,Ng. praeacuta,Ng. sinuosa, and laterNg. spathiconstricta) and the first newMagnigondolella,Mg. mutata. Several of these plusBo.? curvatasp. nov. also occur above thetardusZone in British Columbia (BC). In the next younger ammonoid zone withTirolites, the firstColumbitellaareCb. joanaeandCb. weitschati. Middle SpathianColumbitesandProcolumbitesammonoid beds in the USA are dominated byCb. elongata, whereas the broadly equivalent strata in the north containCb. amica,Cb. brevissp. nov. andCb. paragondolellaeformis. Late Spathian radiation produces six new species ofMagnigondolella:Mg. incurva,Mg.?minutaandMg. trutchensisin theProhungaritesammonoid beds, followed byMg. acuminata,Mg. tozeriandMg. peribolain thehaugiandsubrobustusammonoid zones.