REASSESSMENT OF THE DEVONIAN PROBLEMATICUM PROTONYMPHA AS ANOTHER POST-EDIACARAN VENDOBIONT

Abstract

Protonympha is an enigmatic fossil represented by two species from the Middle Devonian (Protonympha transversa) and Late Devonian (Protonympha salicifolia) of New York. Although interpreted in the past as a polychaete worm or starfish arm, Protonympha is not found with marine fossils, but with fossil plants. This fossil plant community was a swamp woodland of Lepidosigillaria whitei, with ground cover of Haskinsia colophylla, fringing brackish to freshwater coastal lagoons of the Catskill Delta. Protonympha shares with Ediacaran Vendobionta a quilted body of unskeletonized biopolymer that is unusually resistant to burial compaction. In overall form, Protonympha is most like the Ediacaran genus Spriggina. Protonympha has branching and tapering tubular structures radiating from the bottom. These rhizine-like structures, thallus stratification and internal chambers revealed by petrographic thin sections suggest affinities with lichenized fungi. As for Cambrian Swartpuntia and Ordovician-Silurian Rutgersella, Protonympha may have been a post-Ediacaran vendobiont. □ Devonian, New York, Problematicum, Protonympha, vendobiont.

Internal structure of Cambrian vendobionts Arumberia, Hallidaya, and Noffkarkys preserved by clay in Montana, USA

“…This three-dimensional pattern is comparable with thin sections of enigmatic Ediacaran Vendobionta (Seilacher, 1992): Chinese Yangtziramulus zhangi (Xiao et al, 2005;Shen et al, 2009), Namibian Pteridinium simplex (Jenkins, 1992;Grazhdankin & Seilacher, 2002), Swartpuntia germsi (Narbonne et al, 1997), and Ernietta plateauensis (Jenkins et al, 1981;Ivantsov et al, 2015), and Siberian Charnia masoni (Grazhdankin et al, 2008). Also comparable are internal chambers of Silurian Rutgersella (Retallack, 2015a) and Devonian Protonympha (Retallack, 2018). Despite these constructional similarities, these other fossils have subhorizontal zig-zag sutures, midribs, or vanes not seen in Arumberia.…”

“…At intervals of 1-2 mm this central carbonaceous seam has short vertical seams reaching either up or down in the same direction as the flexure at the point of juncture. This distinctive double layer "quilting" (in the sense of Seilacher, 1992) is identical to that of Dickinsonia (Retallack, 2016a), Rutgersella (Retallack, 2015a), and Protonympha (Retallack, 2018), but more complex than the single layer "quilting" pattern of Yangtziramulus (Shen et al, 2009), Pteridinium (Grazhdankin & Seilacher, 2002) and Ernietta (Ivantsov et al, 2015). The vertical struts at inflections also differentiate it from a thin abiotically leached layer.…”

“…The Arumberia-Noffkarkys-Hallidaya community of Fishtrap Lake, and many other localities listed above are evidence that this community did not go extinct at the end of the Ediacaran, and may have persisted into the Ordovician (Bland, 1984;Went, 2005;Budd & Jensen, 2017). Other vendobionts Rutgersella and Protonympha persisted in intertidal to terrestrial habitats in the Silurian (Retallack, 2015a) and Devonian (Retallack, 2018). Thus terrestrial "Mattresslands" of vendobionts (Retallack & Broz, 2020) were unaffected by the evolution and intensification of burrowing organisms of marine "Wormworld" (Schiffbauer et al, 2016).…”

Ediacaran survivors in the Cambrian: suspicions, denials and a smoking gun

“…In this respect, the diversity dynamics of the Ediacaran biota are similar to those of some later clades (Budd & Mann, 2020b;Barnes et al 2021) showing a long period of relative abundance, a partial extinction event and then another long period of survival at lower diversity before eventual extinction, apparently without descendants. Thus, potential causes of their total extinction should be sought, not solely in events around the Cambrian boundary, but in their overall diversity dynamics (taking into account their long Cambrian range) and their last occurrence record, which would be ~508-505 Ma (Aria & Caron, 2017;Landing et al 2020;Saleh et al 2020) based on Thaumaptilon from the Burgess Shale (though see Retallack (2018) for suggestions of a Devonian occurrence).…”

Palaeoproterozoic (2.2 Ga) life on land near Medicine Bow Peak, Wyoming, U.S.A.

“…Radially quilted "Gabonionta", 15-36 mm long, permineralized by pyrite between laminae of grey shales of the FB Formation near Franceville, Gabon, are dated between 2099 ± 30 Ma and 2083 ± 30 Ma, and described as "large colonial organisms with coordinated growth" (El Albani et al, 2010. Although structurally comparable with cellular slime molds such as Dictyostelium (Bonner, 2009), Vendobionta such as Rutgersella (Retallack, 2015a), and bacterial colonies (Ben-Jacob et al, 1994;Shapiro, 1998), these may have been Archaeosporalean fungi like Horodyskia (Retallack et al, 2013a) and Diskagma (Retallack et al, 2013b).…”