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

Abstract

The 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, Magnigondolella and Neogondolella. 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 new Neogondolella species (Ng. bucheri, Ng. darwinensis, Ng. praeacuta, Ng. sinuosa, and later Ng. spathiconstricta) and the first new Magnigondolella, Mg. mutata. Several of these plus Bo.? curvata sp. nov. also occur above the tardus Zone in British Columbia (BC). In the next younger ammonoid zone with Tirolites, the first Columbitella are Cb. joanae and Cb. weitschati. Middle Spathian Columbites and Procolumbites ammonoid beds in the USA are dominated by Cb. elongata, whereas the broadly equivalent strata in the north contain Cb. amica, Cb. brevis sp. nov. and Cb. paragondolellaeformis. Late Spathian radiation produces six new species of Magnigondolella: Mg. incurva, Mg.? minuta and Mg. trutchensis in the Prohungarites ammonoid beds, followed by Mg. acuminata, Mg. tozeri and Mg. peribola in the haugi and subrobustus ammonoid zones.

SPATHIAN (LOWER TRIASSIC) CONODONTS FROM THE <em>TIROLITES CASSIANUS</em> BEDS IN PALEOTETHYS-ISSUED NORTH DOBROGEA OROGEN (ROMANIA)

“…triangularis and Tr. symmetricus Zones from the middle and upper Spathian strata (Orchard 2022). The Tr.…”

An expanded Smithian–Spathian (Lower Triassic) boundary from a reefal build‐up record in Oman: implications for conodont taxonomy, high‐resolution biochronology and the carbon isotope record

“…Orchard (2007) mentioned that P 1 elements similar to ‘ Gladigondolella ’ carinata occur in Spathian collections from Oman and may represent the earliest representatives of that genus (recently described as Bo .? laii in Orchard 2021), although the other elements of the apparatus remain undescribed and do not correspond to those of the type species Gladigondolella tethydis , as reconstructed by Orchard (2005) from the Middle Triassic (hence the quotes). Gladigondolella tethydis itself is known to date only from Anisian strata and it was actually proposed as one of several proxies for the definition of the base of the Anisian (Goudemand et al .…”

“…13A), in Kashmir (M. Leu, collection from 2013 Guryul Ravine expedition stored at University of Zurich), or in North America (compare Fig. 18A with Orchard 2021, fig. 9N).…”

“…A formal description of this species is still pending. Although Orchard (2021) assigned this species to ‘ Borinella ’ laii (Chen et al . 2021), the latter usually develops a posterior denticle behind the large cusp, which is not the case in the illustrated specimen of Orchard (2021, fig.…”

Elevated sedimentation of clastic matter in pelagic Panthalassa during the early Olenekian

“…However, Koike (2016) revised the apparatus of Co. breviramulis to a normal octomembrate composition by merging the one reconstructed in Koike (1996) with components of the Ellisonia dinodoides (Tatge) apparatus in Koike (1994), which was reconstructed based on collections from the same interval in the same section. Although Koike (2016) continued to place the multielement species under the genus Cornudina, perhaps due to its more common usage (e.g., Chen et al, 2016;Orchard, 2005), the selection of Chirodella by the first reviser (Kozur & Mostler, 1971) has priority.…”