DOI: 10.5061/dryad.dbrv15f4x
title: Data for: Frond orientations with independent current indicators demonstrate the reclining rheotropic mode of life of several Ediacaran rangeomorph taxa

description: Fossils from the deep-sea Ediacaran biotas of Newfoundland are among the
 oldest architecturally complex soft-bodied macroorganisms on Earth. Most
 organisms in the Mistaken Point-type biotas of Avalonia — particularly the
 fractal-branching frondose Rangeomorpha — have been traditionally
 interpreted as living erect within the water column during life. However,
 due to the scarcity of documented physical sedimentological proxies
 associated with fossiliferous beds, Ediacaran paleocurrents have been
 inferred in some instances from the preferential orientation of fronds.
 This calls into question the relationship between frond orientation and
 paleocurrents. In this study, we present an integrated approach from a
 newly described fossiliferous surface (the “Melrose Surface” in the
 Fermeuse Formation at Melrose, on the southern portion of the Catalina
 Dome in the Discovery UNESCO Global Geopark) combining: (1) physical
 sedimentological evidence for paleocurrent direction in the form of
 climbing ripple cross lamination, and (2) a series of statistical analyses
 based on modified polythetic and monothetic clustering techniques
 reflecting the circular nature of the recorded orientation of Fractofusus
 misrai specimens. This study demonstrates the reclining rheotropic mode of
 life of the Ediacaran rangeomorph taxon Fractofusus misrai and presents
 preliminary inferences suggesting a similar mode of life for Bradgatia sp.
 and Pectinifrons abyssalis based on qualitative evidence. These results
 advocate for the consideration of an alternative conceptual hypothesis for
 the position of life of Ediacaran organisms in which they are interpreted
 as having lived reclined on the seafloor, in the position that they are
 preserved.
description: The data presented in this study were collected from a single
 fossiliferous surface of the Fermeuse Formation that crops out on the
 southeastern margin of the Catalina Dome, Bonavista Peninsula (see O’Brien
 and King 2005) (Fig. 2). A 0.1-0.6 mm thick ripple cross-laminated
 sandstone bed indicates a paleocurrent orientation of 102º SE. Data
 collection was grid-based, with 41 squares of approximately 1.5 x 1.5 m
 completely documented with respect to their paleontology. Grids were
 photographed and orientation data collected (n<sub>t</sub> =
 208 specimens of five different taxa were
 measured: <em>Fractofusus</em> n<sub>f</sub> = 190, <em>Pectinifrons</em> n<sub>p</sub> = 12, <em>Bradgatia</em> n<sub>b</sub> = four, <em>Primocandelabrum</em> n<sub>pr</sub> = one, and <em>Charniodiscus</em> n<sub>c</sub> = one). Fragmental specimens of all studied taxa were excluded from the analysis due to analytical difficulties and potential to introduce sampling bias. Only <em>Fractofusus</em> was included in the statistical analysis due to the low numbers of well-preserved specimens of all other taxa.  Morphometric traits were retrieved from field photography and analysed with the software ImageJ (Schneider et al. 2012). The data were analysed by the Gaussian finite mixture model-based clustering algorithms of the package mclust (Scrucca et al. 2016). The circular variable was tested to identify potential departures from uniformity using the packages circular (Agostinelli and Lund 2017) and CircMLE (Fitak and Johnsen 2017). Modified monothetic and polythetic cluster analysis were conducted aided by the monoClust package in R (Tran et al. 2021). 
description: Microsoft Excel; R.