Acanthodian scales and worm tubes from the Kapp Kjeldsen Division of the Lower Devonian Wood Bay Formation, Spitsbergen

Abstract

Results of a thin section study of bonebeds from the Kapp Kjeldsen Division are presented and discussed. The material for this study was collected in the talus on the south‐eastern side of Bockfjorden, northern Spitsbergen. The stratigraphical position of the Kapp Kjeldsen Division within the Devonian strata of Spitsbergen is shown in Table 1. The thin sections for this study were not made to standard thickness, but are slightly thicker for better resolution of the vertebrate material. Each thin section was individually polished. The photos are made with crossed nichols.

Adaptive function and phylogenetic significance of novel skeletal features of a new Devonian microconchid tubeworm (Tentaculita) from Wyoming, USA

“…Only their calcified female fructifications (gyrogonites) are usually fossilized and provide evidence for the presence of the charophyte. Such microconchid–gyrogonite associations are known from the fossil record (Racki and Racka, 1981; Ilyes, 1995; Zatoń and Peck, 2013; Shcherbakov et al, 2021), indicating that at least some microconchids might have colonized these algae. Assuming that Aculeiconchus n. gen. microconchids lived similarly to some bryozoans, their basal spines could be the sole evidence of the former presence of algae to which they attached.…”

“…On the basis of numerous examples, Zatoń et al (2016b) rejected this hypothesis and supported the idea that microconchids originated in the Late Ordovician in shallow shelf environments and later colonized marginal marine environments, and eventually freshwater habitats by the Early Devonian through the evolution of osmoregulation (Zatoń et al, 2012a), as did ostracodes during their invasion of freshwater habitats (Bennett, 2008). Indeed, the colonization of freshwater habitats by microconchids is supported by firm paleontological evidence, e.g., their coexistence with such terrestrial or freshwater components as vascular plant remains (Sandberg, 1963; Brower, 1975; Mastalerz, 1996; Zatoń and Mazurek, 2011; Caruso and Tomescu, 2012; Florjan et al, 2012; Zatoń and Peck, 2013; Shcherbakov et al, 2021), charophytes (Ilyes, 1995; Zatoń and Peck, 2013; Shcherbakov et al, 2021), spinicaudatans, and freshwater ostracodes and bivalves (Trueman, 1942; Zatoń and Peck, 2013; Shcherbakov et al, 2021).…”

Acanthodians from the Silurian–Devonian boundary beds of Novaya Zemlya Archipelago, Russia

“…Early Devonian acanthodians have been described from several Arctic regions that were relatively close by at the time, including: Severnaya Zemlya: acanthodian articulated fish and isolated scales described by Valiukevičius (1992Valiukevičius ( , 1994Valiukevičius ( , 2003a; Spitsbergen: acanthodian scales, jaw bones and fin spines reported by Ørvig (1957, 1969), Blieck et al (1987), Ilyes (1995) and Harland (1997), plus Pragian-Emsian acanthodian trace fossils Undichna by Wisshak et al (2004); and Chukotka: rare acanthodian scales described by Mark-Kurik et al (2013). The late Silurian-Early Devonian acanthodians from the Baltic countries, on the other hand, have been extensively described, starting with Pander (1856).…”