TY - JOUR

T1 - Seaweeds through time: Morphological and ecological analysis of Proterozoic and early Paleozoic benthic macroalgae

AU - Bykova, Natalia

AU - LoDuca, Steven T.

AU - Ye, Qin

AU - Marusin, Vasiliy

AU - Grazhdankin, Dmitriy

AU - Xiao, Shuhai

N1 - Funding Information: We would like to thank Benjamin Gill, Brian Romans, and Sterling Nesbitt for comments on the early version of the manuscript; LISA (Laboratory for Interdisciplinary Statistical Analysis) at Virginia Tech for providing help with statistical analyses; and Michal Kowalewski for advice on statistical analyses. We also thank John Huntley and two anonymous reviewers for constructive comments. This research was funded by NASA Exobiology and Evolutionary Biology Program (80NSSC18K1086), U. S. National Science Foundation (EAR 1250756, 1332320, 1528553), Russian Science Foundation (14-17-00409; 17-17-01241), Russian Foundation for Basic Research (18-05-70110; 20-35-70016), National Geographic Society (8227-07, 8637-09, 9031-11), National Postdoctoral Program for Innovative Talents (BX20180278 to Q.Y.), and a GSA Graduate Student Research Grant. This publication was prepared under Government Contract 0331-2019-0002 (Ministry of Education and Science of the Russian Federation). Publisher Copyright: © 2020 Elsevier B.V. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/11

Y1 - 2020/11

N2 - Benthic marine macroalgae or seaweeds are key ecological players in oceans today and have been since the Proterozoic. To date, however, morphological and evolutionary patterns for Precambrian macroalgae have been documented only in rather broad terms. To refine our understanding in this critical interval, we updated a dataset of Proterozoic to early Paleozoic noncalcified macroalgal fossils preserved as macroscopic carbonaceous compressions. The data were analyzed using non-parametric multidimensional scaling (NMDS) and functional-form group (FFG) approaches, in order to characterize morphological and ecological evolutionary patterns of these macroalgae. At the broadest scale, the results show progressive increases in thallus size, morphospace range, and aspects of ecological complexity such as canopy heights, surface area/volume ratios, and functional-form groups through time. These trends, however, are not always monotonous. In particular, significant increases in Proterozoic macroalgal morphological diversity and maximum size appear to have occurred in the Neoproterozoic (Tonian and Ediacaran periods, respectively). Analysis of Ediacaran macroalgal assemblages shows that macroalgae broadly follow the Ediacara-like fossil assemblages, with a significant drop in most studied metrics in the terminal Ediacaran stage (~550–539 Ma). The latter event occurs during the Kotlinian crisis experienced by Ediacara-type macro-organisms, highlighting the possibility that this extinction event during the Ediacaran-Cambrian transition affected both macroalgae and Ediacara-type macro-organisms. Our analysis also confirms an Ordovician increase in the morphological and ecological diversity of macroalgae.

AB - Benthic marine macroalgae or seaweeds are key ecological players in oceans today and have been since the Proterozoic. To date, however, morphological and evolutionary patterns for Precambrian macroalgae have been documented only in rather broad terms. To refine our understanding in this critical interval, we updated a dataset of Proterozoic to early Paleozoic noncalcified macroalgal fossils preserved as macroscopic carbonaceous compressions. The data were analyzed using non-parametric multidimensional scaling (NMDS) and functional-form group (FFG) approaches, in order to characterize morphological and ecological evolutionary patterns of these macroalgae. At the broadest scale, the results show progressive increases in thallus size, morphospace range, and aspects of ecological complexity such as canopy heights, surface area/volume ratios, and functional-form groups through time. These trends, however, are not always monotonous. In particular, significant increases in Proterozoic macroalgal morphological diversity and maximum size appear to have occurred in the Neoproterozoic (Tonian and Ediacaran periods, respectively). Analysis of Ediacaran macroalgal assemblages shows that macroalgae broadly follow the Ediacara-like fossil assemblages, with a significant drop in most studied metrics in the terminal Ediacaran stage (~550–539 Ma). The latter event occurs during the Kotlinian crisis experienced by Ediacara-type macro-organisms, highlighting the possibility that this extinction event during the Ediacaran-Cambrian transition affected both macroalgae and Ediacara-type macro-organisms. Our analysis also confirms an Ordovician increase in the morphological and ecological diversity of macroalgae.

KW - Ediacaran

KW - Functional-form groups

KW - Kotlinian crisis

KW - Macroalgae

KW - Morphospace

KW - Proterozoic

KW - CARBONACEOUS COMPRESSION FOSSILS

KW - ROHTAS FORMATION

KW - VINDHYAN SUPERGROUP

KW - SEMRI GROUP

KW - FUNCTIONAL-FORM

KW - BIOTA

KW - EVOLUTION

KW - NEOPROTEROZOIC DOUSHANTUO FORMATION

KW - NAMA GROUP

KW - EDIACARAN-CAMBRIAN TRANSITION

UR - http://www.scopus.com/inward/record.url?scp=85090035986&partnerID=8YFLogxK

U2 - 10.1016/j.precamres.2020.105875

DO - 10.1016/j.precamres.2020.105875

M3 - Article

AN - SCOPUS:85090035986

VL - 350

JO - Precambrian Research

JF - Precambrian Research

SN - 0301-9268

M1 - 105875

ER -