Rare stromatoporoids from the Lower Devonian (Emsian) of Nevada, and their biostratigraphic and paleobiogeographic significance

Abstract

Two previously known species of stromatoporoids are reported from Nevada: Stromatoporella perannulata, from the Bartine Member of the McColley Canyon Formation (middle Emsian); and Stictostroma moosense, from the Oxyoke Canyon Sandstone (uppermost Emsian). A new species, Syringodictyon nevadense n. sp., is described from the Coils Creek Member of the McColley Canyon Formation (upper Emsian). Stromatoporella perannulata also occurs in Emsian-age strata on Ellesmere Island, arctic Canada, and in strata of Emsian and/or Eifelian age in Ontario, New York, Ohio, and Kentucky. Outside Nevada, Syringodictyon is confined to the Emsian of Ellesmere Island, and Emsian/Eifelian of Ontario and New York. Stictostroma moosense is known from only the Emsian/Eifelian of Ontario. It is concluded that the three Nevada specimens are Emsian in age. This implies that in other localities where two of the species, S. perannulata and S. moosense, occur in strata where the placement of the Emsian-Eifelian boundary is in question, it might be higher than previously thought. The presence of the two species, plus Syringodictyon, in both the Old World Realm (Nevada, arctic Canada) and the Eastern Americas Realm (Ontario, New York, Ohio, Kentucky), infers a selective marine connection between the two realms that was not available to other taxa. The breach in the inter-realm barrier most likely occurred as a shallow seaway across the Canadian Shield. UUID: http://zoobank.org/e73023c6-88ca-4b4d-9b01-f74a75b99c43

Devonian stromatoporoid historical collections in the Natural History Museum, London (UK): redescription, taxonomic revision and implications for stromatoporoid global paleobiogeography

“…100 million-year evolutionary history, reaching their highest biodiversity in the Eifelian Stage (Stearn, 2015a), and during the Givetian-Frasnian Stages showing the highest abundance over global carbonate platforms manifested by reef occurrences (Copper, 2002). The extensive presence of Devonian stromatoporoids has attracted attention in taxonomy over the past two centuries, particularly in regions as western Europe (Goldfuss, 1825;Bargatzky, 1881;Nicholson, 1886Nicholson, -1892Lecompte, 1951Lecompte, -1952, Russia (Yavorsky, 1931(Yavorsky, , 1955(Yavorsky, -1967, Australia (Ripper, 1933(Ripper, , 1937aCockbain, 1984;Cook, 1999), North America (Parks, 1936;Galloway and St. Jean, 1957;Stearn, 1963;Stock, 2022), the Middle East (Mistiaen, 1985;Mistiaen and Gholamalian, 2000), and South China (Yang and Dong, 1979;Dong, 2001;Huang et al, 2022).…”