Sponge spicule assemblages from the Cambrian (Series 2–3) of North Greenland (Laurentia): systematics and biogeography

Abstract

Isolated microscopic spicules from disarticulated scleritomes demonstrate the presence of a diverse sponge fauna otherwise not evident from the macrofossil record in carbonate successions deposited during the unnamed Cambrian Series 2 and Cambrian Series 3 (Miaolingian) in North Greenland. Most of the spicule morphotypes are not recognised from faunas of articulated sponges known from contemporaneous siliciclastic strata elsewhere. Assemblages are described in terms of four Cambrian stages and contain numerous spicule morphotypes not previously recorded from Laurentia. Many of the spicules can be correlated worldwide, however, extending current knowledge of the biogeographic distribution of sponge spicule-based taxa in the Cambrian. In particular, similar Cambrian Stage 4 (Series 2) and Miaolingian assemblages (Wuliuan, Drumian and Guzhangian stages) faunas are recorded from tropical palaeolatitudes in Australia, South China, Siberia and Laurentia, although this may in part reflect a methodology focused on the preparation of the carbonate samples that dominate these successions. New spicule-based taxa: Eiffelia floriformis n. sp., Australispongia? inuak n. sp., Celtispongia dorte n. gen. n. sp., Sanningasoqia borealis n. gen. n. sp., Speciosuspongia inughuitorum n. sp., Sulukispicula gelidae n. gen. n. sp.

An outer shelf shelly fauna from Cambrian Series 2 (Stage 4) of North Greenland (Laurentia)

“…7.11). In the context of North Greenland spicule assemblages, these distinctive spicules were reported by Peel (2019a) from several localities within the Kap Troedsson and Aftenstjernesø formations in North Greenland. The four paratangential rays may lie within a single plane perpendicular to the axial ray, but they are often inclined, or slightly curved, towards it.…”

“…Remarks. -Botting and Muir (2018) considered that the widely used name Calcihexactina Sdzuy, 1969 for spicules of this type lacked any useful meaning, and Peel (2019a) recommended that it should be restricted to the type suite. Common hexactins and rare pentactins from GGU sample 315045 are characterized by long, slender rays of uniform diameter and with a circular cross-section (Fig.…”

“…Peel (2019a) reported robust spicules of the calcarean Eiffelia from the Aftenstjernesø and Kap Troedsson formations at several localities in North Greenland. Single specimens of six-rayed (Fig.…”

“…Botting and Muir (2018) considered that the widely used name Calcihexactina Sdzuy, 1969 for spicules of this type lacked any useful meaning, and Peel (2019a) recommended that it should be restricted to the type suite.…”

“…The bivalve Fordilla Barrande, 1881 may be locally common in southern Peary Land, but is not present at Navarana Fjord. Published records include Peel et al (1974), Runnegar and Pojeta, (1992), Atkins and Peel (2004, 2008), Vendrasco et al (2011a), and Peel (2019a, b).…”