Limbunyasphaera operculata is a new species that shows a small door opening into the cell.
Photo Credit
Riedman et al.
By 1.64 billion years ago, eukaryote organisms had already evolved out of prokaryote cells and had diversified into a range of complex organisms. For creationists, this was more than 1.6 billion years before the Universe existed and way back in the dim and distant past before humans were supposedly magicked out of dirt in 'Creation Week.
The prevailing scientific consensus was that eukaryotes only diversified significantly about 800 million years ago, but a paper published in the Paleaontological Society's journal Papers in Palaeontology throws this back to double that age almost to the beginnings of eukaryote evolution. The paper is the work of palaeontologists from the Department of Earth Science, University of California at Santa Barbara, Santa Barbara, California, USA and the Department of Earth & Planetary Sciences/Geotop, McGill University, Montreal, Quebec, Canada.
The team arrived at this conclusion by examining microfossils recovered from 430 samples from eight cores drilled by a prospecting company in Australia's Northern Territory. The cores used for this study spanned roughly 500 meters of stratigraphy, or 133 million years, with around 15 million years of significant deposition. They consisted of shale and mudstone: remnants of an ancient coastal ecosystem that alternated between shallow, subtidal mudflats and coastal lagoons.
The microfossils were extracted from the rock by disolving it in hydrofluoric acid, then examined under microscopes. The team recorded 26 taxa, including 10 previously undescribed species.
From the UC Santa Barbara news release:
The team found indirect evidence of cytoskeletons, as well as platy structures that suggest the presence of internal vesicles in which the plates were formed — perhaps ancestral to Golgi bodies, present in modern eukaryotic cells. Other microbes had cell walls made of bound fibers, similarly suggestive of the presence of a complex cytoskeleton.One question still to be answered is whether these early eukaryotes had mitochondria, so were aerobic or whether they were still anaerobic. All eukaryotes, which includes all animals, plants and fungi now have mitochondria, so the common ancestor of all modern eukaryotes must have acquired them at some point; the question is when.
The authors also found cells with a tiny trapdoor, evidence of a degree of sophistication. Some microbes can form a cyst to wait out unfavorable environmental conditions. In order to emerge, they need to be able to etch an opening in their protective shell. Making this door is a specialized process. “If you’re going to produce an enzyme that dissolves your cell wall, you need to be really careful about how you use that enzyme,” Riedman [lead author] said. “So in one of the earliest records of eukaryotes, we’re seeing some pretty impressive levels of complexity.”
Many people in the field had thought this ability emerged later, and the evidence for it in this assemblage further emphasizes how diverse and advanced eukaryotes were even at this early juncture. “The assumption has always been that this is around the time that eukaryotes appeared. And now we think that people just haven’t explored older rocks,” said co-author Susannah Porter, an Earth science professor at UC Santa Barbara.
Mitochondria are the descendants of bacteria which had become endosymbionts of early eukaryotes. These bacteria had evolved the ability to use the chemical energy in sugars such as glucose and store it in ATP which could then be used to power other metabolic processes. Incorporating them into the early eukaryotes would have given the eukaryotes a considerable advantage in the presence of atmospheric oxygen, to the extent that they quickly replaced the anaerobic eukaryotes.
The team give more technical details in their published paper:
AbstractClearly, if eukaryotes had evolved a degree of complexity indicating specialisation, they had been doing so for some considerable time, which pushes their evolution by endosymbiosis from archaea and bacteria back beyond 1.6 billion years. And they were to continue to evolve up to the point where they diversified again into single-celled and multicellular organisms.
Fine-grained, siliciclastic units of the >1642 ± 3.9 Ma late Palaeoproterozoic Limbunya Group, Birrindudu Basin host rich, well-preserved organic-walled microfossil assemblages that include members of total-group eukaryotes. These assemblages include taxa characteristic of this interval such as Tappania plana and Satka favosa, as well as less common taxa such as Gigantosphaeridium fibratum, Gigantosphaeridium floccosum, Kamolineata elongata (= Valeria elongata; new combination), and four new species. The new taxa include Limbunyasphaera operculata gen et sp. nov., the oldest known operculate taxon; the large septate filaments of Siphonoseptum bombycinum gen. et sp. nov.; the platy tubular form Birrindudutuba brigandinia gen. et sp. nov.; and Filinexum torsivum gen. et sp. nov., which bears a spirally twisted wall constructed of bound fibres. Our data show that eukaryotic fossils are particularly abundant in marginal marine environments such as tidal flats and back-barrier lagoonal settings. This is exemplified by the Blue Hole Formation, which features an especially diverse and complex assemblage. We also present a new within-formation eukaryotic species richness estimate for the Palaeoproterozoic to Tonian. This estimate indicates that the oldest eukaryote-bearing units already show species richness levels similar to those of the much younger and more heavily sampled Tonian period. Additionally, these oldest eukaryotic assemblages show significant morphological disparity, particularly in vesicle construction. These high levels of eukaryotic species richness and morphological disparity suggest that although late Palaeoproterozoic units preserve our oldest record of eukaryotes, the eukaryotic clade has a much deeper history.
The late Palaeoproterozoic was a time of wonder, postdating the global increase in atmospheric oxygen that occurred between 2.5 and 2.1 Ga, referred to as the Great Oxidation Event (GOE; Lyons et al. 2014, 2021); a possibly global glacial interval known as the Huronian Icehouse Period from 2.45 to 2.22 Ga (Bekker 2015; Bekker et al. 2020) and a major perturbation to the global carbon cycle reflected in the Lomagundi–Jatuli isotopic anomaly (c. 2.3–2.1 Ga; Martin et al. 2013). In the wake of these events, and during the formation (c. 1.9–1.8 Ga) and break-up (1.7–1.3 Ga) of the supercontinent Nuna (Evans & Mitchell 2011), and shifts in ocean chemistry (e.g. Poulton et al. 2010; Rasmussen et al. 2012), significant steps in early eukaryotic evolution are hypothesized to have taken place (Chernikova et al. 2011.1; Parfrey et al. 2011.2; Eme et al. 2014.1; Betts et al. 2018; Porter & Riedman 2023).
Molecular clock analyses offer broad estimates for the timing of the emergence of eukaryotes, with the eukaryotic total group (marked by the appearance of the first eukaryotic common ancestor) probably appearing sometime between c. 3000 and 2300 Ma (Betts et al. 2018) and crown group eukaryotes (heralded by the last eukaryotic common ancestor; LECA) probably appearing between c. 1900 and 1000 Ma (Chernikova et al. 2011.1; Parfrey et al. 2011.2; Eme et al. 2014.1; Betts et al. 2018). Recently published palaeontological analyses have shown that the biosphere of the late Palaeoproterozoic to middle Mesoproterozoic was more complex than had previously been thought, pushing back on the narrative of an environmental throttle on eukaryotic diversification (e.g. Butterfield 2015.1; Reinhard et al. 2016), and suggesting that this interval was no humdrum giga-annum.
The oldest currently available evidence of eukaryotes dates from the latest Palaeoproterozoic Era with complexly ornamented taxa such as the concentrically striated Valeria lophostriata from the Changcheng Group (1673–1638 Ma: Lamb et al. 2009; Miao et al. 2019), the Ruyang Group (1711 ± 57–1411 ± 27 Ma: Agić et al. 2017) and the Mallapunyah Formation of the McArthur Group (c. 1650 Ma: Javaux 2007). The complex and highly variable species Tappania plana is also considered to be eukaryotic and is found in the Ruyang Group (Yin et al. 2005; Agić et al. 2017), the Bahraich Group (c. 1631 Ma: Prasad & Asher 2001) and younger units such as the c. 1500–1400 Ma Roper Group (Javaux & Knoll 2017.1), the c. 1580–1450 Ma Belt Supergroup (Adam et al. 2017.2) and the c. 1500–1100 Ma Kamo Group (Nagovitsin 2009.1). Although these fossils cannot be readily assigned to an extant lineage, they represent at least stem-group eukaryotes (i.e. those that branch off from the eukaryotic lineage before the origin of the crown group). Here we add to the fossil record of this interval, presenting new data on organic-walled microfossils of the late Palaeoproterozoic Limbunya Group from the Birrindudu Basin, northern Australia, and in particular the assemblage of the 1636 ± 5 Ma Blue Hole Formation.
Birrindudutuba brigandinia gen. et sp. nov. All specimens are from the Blue Hole Formation, DD90VRB1 drillcore. A–C, holotype, DD90VRB1_425.57m, 58A_W28/4_(MAGNT P16020); note tearing between and around plates, not through the plates; C, note possible concave or lenticular shape of plates, particularly in the lower left edge. D–E, DD90VRB1_430.09m, 59_J31/3_(CSR0558-014). F, DD90VRB1_430.09m, 59_P37/3_(CSR0558-014). G, DD90VRB1_425.57m, GG13_N30/0_(MAGNT P16021). H, DD90VRB1_413.7m, GG12_R42/0_(MAGNT P16023). I, DD90VRB1_425.57m, 58A_V25/4_(MAGNT P16020). Scale bar represents: 20 μm (A, C, D); 50 μm (B, E–I)
Gigantosphaeridium spp. and Germinosphaera spp. A–E, Gigantosphaeridium fimbriatum. A–B, DD90VRB1_425.57m, GG13_K46/3_(MAGNT P16021). C, DD90VRB1_409.65m, 55_J31/3_(CSR0558-005). D–E, DD90VRB1_413.7m, GG11_L48/1_(MAGNT P16022). F, Germinosphaera bispinosa, DD90VRB1_425.57m, 58B_L35/3_(CSR0558-012). G, cf. Germinosphaera sp.; note frequent, fine processes covering vesicle; DD90VRB1_425.57m, GG13_G50/0_(MAGNT P16021). H–I, Gigantosphaeridium floccosum, DD90VRB1_409.65m, 55_K29/0_(CSR0558-005), Scale bar represents: 50 μm (A, C, D, F–H); 20 μm (B, E, I).
High magnification comparison of Valeria lophostriata and Kamolineata elongata. A, V. lophostriata, Mallapunyah Formation, drillcore MCDD0005 179.13m. B, K. elongata.
Satka favosa specimens from DD90VRB1. A, DD90VRB1_157.9m, 18_O22/4_(CSR0558-003). B, DD90VRB1_365.4m, 19_J23/4_(CSR0558-004). C, DD90VRB2_149.93m, 22B_N27/4_(CSR0558-002). D, DD90VRB1_413.7m, GG11_X41/4_(MAGNT P16022). E, DD90VRB1_157.9m, 18_O32/2_(CSR0558-003). F, DD90VRB1_413.7m, GG12_U18/4_(MAGNT P16023). Scale bar represents 20 μm.
Spiromorpha segmentata. In A, B, D and F–K, note tearing between segments, which in E has resulted in the preservation of a ring of only two segments. In B–D, G, J and K, note small divots or openings in terminal segments. In F, note thin annular strings associated with spaces between segments. The specimen in C is preserved in the process of fission or perhaps conjugation as hypothesized by Yin et al. (2005). In G–I, note complex arcuate folds or creases. A, DD90VRB1_413.7m, GG12_R40/1_(MAGNT P16023). B, DD90VRB1_413.7m, GG12_P37/2_(MAGNT P16023). C, DD90VRB1_420.27m, GG10_R30/3_(CSR0558-011). D, DD90VRB1_413.7m, GG12_O39/0_(MAGNT P16023). E, DD90VRB1_425.57m, 58A_L24/1_(MAGNT P16020). F, DD90VRB1_413.7m, GG12_T37/3_(MAGNT P16023). G, DD90VRB1_430.09m, 59_V33/3_(CSR0558-014). H, DD90VRB1_425.57m, 58A_U37/1_(MAGNT P16020). I, DD90VRB1_425.57m, 58A_M22/3_(MAGNT P16020). J, DD90VRB1_425.57m, 58B_O31/1_(CSR0558-012). K, DD90VRB1_425.57m, 58A_R31/4_(MAGNT P16020). Scale bar represents 20 μm.
Valeria lophostriata and unnamed species A and B. A, unnamed species A; note the finely granular texture, small frequent bumps visible along the periphery and bundles of fine processes; DD90VRB1_425.57m, GG13_L47/0_(MAGNT P16021). B–D, unnamed species B; note the square to rectangular elements that perhaps are vesicle regions separated by folding of the vesicle rather than distinct plates; B, DD90VRB1_157.9m, 18_U35/3_(CSR0558-003). C, DD90VRB1_157.9m, 18_L30/1_(CSR0558-003). D, DD90VRB1_157.9m, 18_X29/0_(CSR0558-003). E–F, Valeria lophostriata; note the typical fine striations that appear to be grouped into c. 1.5 μm ridges; DD90VRB1_425.57m, 58B_P14/4_(CSR0558-012). Scale bar represents: 20 μm (A–D, F); 10 μm (E).
Unnamed species C–H. A–C, unnamed species C, note the dark band tracing a great circle, particularly visible in C: A, DD90VRB1_413.7m, GG11_T44/4_(MAGNT P16022); B, DD90VRB1_413.7m, GG11_G45/4_(MAGNT P16022); C, DD90VRB1_413.7m, GG12_U33/3_(MAGNT P16023). D, unnamed species D; note parallel to semi-parallel fine linear elements; DD90VRB1_430.09m, 59_M24/0_(CSR0558-014). E, unnamed species E; note the black arrows indicating widely spaced striations; DD90VRB1_413.7m, GG12_P37/2_(MAGNT P16023). F, unnamed species F; note several flaps of vesicle, the protuberance at upper right may simply be overlapping filamentous fossil similar to Siphonophycus spp.; DD90VRB1_425.57m, GG13_U31/4_(MAGNT P16021). G, unnamed species G; note the bulb-shaped vesicle and tubular extension; DD90VRB1_425.57m, 58B_Y30/1_(CSR0558-012). H–K, unnamed species H; note woven texture; H–I, DD90VRB1_425.57m, 58B_T18/2_(CSR0558-012); J–K, DD90VRB1_425.57m, 58A_J39/3_(MAGNT P16020). Scale bar represents: 20 μm (A–G, I, J); 10 μm (H, K).
cf. Dictyosphaera macroreticulata. Note circular to oval markings on the vesicles. All specimens are from the Blue Hole Formation, DD90VRB1 drillcore. A, DD90VRB1_365.4m, 19_T27/4_(CSR0558-004). B, DD90VRB1_417.4m, 56A_R37/1_(CSR0558-008). C, DD90VRB1_413.7m, 20B_N29/1_(CSR0558-007). D, DD90VRB1_413.7m, GG12_M37/3_(MAGNT P16023). Scale bar represents 20 μm.
Kamolineata elongata comb. nov. and Filinexum torsivum gen. et sp. nov. A–B, Kamolineata elongata; note fraying of fibres at edges of degraded specimen B: A, DD90VRB1_420.27m, GG10_V32/0_(CSR0558-011); B, DD90VRB2_149.93m, 22B_R17/1_(CSR0558-002). C–E, Filinexum torsivum; note fine fibres in a spiralling pattern that gives a rhomboidal appearance: C, DD90VRB1_425.57m, GG13_U32/0_(MAGNT P16021); D, holotype, DD90VRB1_425.57m, GG13_T32/1_(MAGNT P16021); note individual fibres visible and frayed at the right end of specimen, also faint annulations; E, DD90VRB1_413.7m, GG11_V39/0 (MAGNT P16022). Scale bar represents 20 μm.
Limbunyasphaera operculata gen. et sp. nov., all specimens from DD90VRB1, depth 413.7 m. In A–D and F, the vesicle has opened, showing pylome and attached operculum. In A–E, note the dark circle on operculum and lighter coloured region outward from that dark circle. In G, the operculum still in place, dark line and edge of operculum just barely visible. In H, the operculum appears to be on the back side of the fossil and a dark body is seen inside the vesicle. In I and J, the operculum appears to have begun to separate from the pylome. A, DD90VRB1_413.7m, GG12_R26/0_(MAGNT P16023). B, DD90VRB1_413.7m, GG12_H35/3_(MAGNT P16023). C, DD90VRB1_413.7m, 20A_Q38/4_(CSR0558-006). D, holotype; DD90VRB1_413.7m, GG11_S29/4_(MAGNT P16022). E, DD90VRB1_413.7m, 20A_O21/3_(CSR0558-006). F, DD90VRB1_413.7m, 20A_T37/0_(CSR0558-006). G, DD90VRB1_413.7m, GG12_F41/4_(MAGNT P16023). H, DD90VRB1_413.7m, GG12_P28/1_(MAGNT P16023). I, DD90VRB1_413.7m, 20B_N26/3_(CSR0558-007). J, DD90VRB1_413.7m, 20B_F15/4_(CSR0558-007). Scale bar represents 20 μm.
Siphonoseptum bombycinum gen. et sp. nov. Note the thin, delicate vesicle with frequent longitudinal folds. In B, D, E and G, specimens show possible differentiation of terminal chamber. In C and I, note small, dark, circular bodies associated with annulations; in particular on I, they appear to be on the outside of the vesicle or of significantly different character, given that the vesicle has torn around but not through them. In E and F, note the ruffled appearance associated with annulations (white arrow in F); in F, the black arrow indicates flexible cross-walls bulging beyond annulation. A, DD90VRB1_413.7m, GG11_L34/0_(MAGNT P16022). B, holotype; DD90VRB1_413.7m, GG12_L41/4_(MAGNT P16023). C, DD90VRB1_413.7m, GG12_Q24/0_(MAGNT P16023). D, DD90VRB1_413.7m, GG12_H21/1_(MAGNT P16023). E, DD90VRB1_425.57m, 58A_P26/1_(MAGNT P16020). F, DD90VRB1_413.7m, GG12_F35/3_(MAGNT P16023). G, DD90VRB1_420.27m, GG10_N31/4_(CSR0558-011). H, DD90VRB1_413.7m, 20B_H38/3_(CSR0558-007). I, DD90VRB1_430.09m, 59_F25/3_(CSR0558-014). Scale bar represents 50 μm.
Tappania plana specimens from drillcore DD90VRB1. Occasionally processes arise from broad conical swellings (D, E, G), but sometimes there is little to no conical base to the processes (B, C, F). Processes sometimes flare distally (A, D) or terminate in fine bristles (B). A, DD90VRB1_420.27m, GG10_T33/0_(CSR0558-011). B, DD90VRB1_420.27m, GG10_T33/0_(MAGNT P16022). C, DD90VRB1_413.7m, GG12_G42/4_(MAGNT P16023). D, DD90VRB1_413.7m, GG12_J49/1_(MAGNT P16023). E, DD90VRB1_413.7m, GG11_O39/4_(MAGNT P16022). F, DD90VRB1_420.27m, GG10_M22/2_(CSR0558-011). G, DD90VRB1_413.7m, GG11_L12/1_(MAGNT P16022). H, DD90VRB1_419.52m, 57_W25/2_(CSR0558-010). Scale bar represents 20 μm.
Leiosphaeridia spp., Pterospermopsimorpha sp., Navifusa majensis, Siphonophycus spp., Oscillatoriopsis obtusa, Tortunema patomica. A, Oscillatoriopsis obtusa, DD90VRB1_413.7m, GG11_V45/3_(MAGNT P16022). B, Tortunema patomica, DD90VRB1_417.4m, 56B_Q33/0_(CSR0558-009). C, Siphonophycus robustum, DD90VRB2_87.7m, 60_Q37/0_(CSR0558-001). D, Siphonophycus solidum, DD90VRB1_425.57m, 58A_T27/1_(MAGNT P16020). E, Siphonophycus septatum mass, DD90VRB1_425.57m, GG14_L48/3_(CSR0558-013). F, Oscillatoriopsis obtusa, DD90VRB1_413.7m, GG11_U28/2_(MAGNT P16022). G, Siphonophycus typicum, DD90VRB2_87.7m, 60_Q23/0_(CSR0558-001). H, Siphonophycus kestron, DD90VRB1_419.52m, 57_K29/4_(CSR0558-010). I, Siphonophycus punctatum, DD90VRB1_425.57m, 58B_H22/1_(CSR0558-012). J, Navifusa majensis, DD90VRB1_413.7m, GG12_F42/0_(MAGNT P16023). K, Pterospermopsimorpha sp., DD90VRB1_413.7m, 20A_L35/1_(CSR0558-006). L, Pterospermopsimorpha sp., DD90VRB1_425.57m, 58A_W20/0_(MAGNT P16020). M, Pterospermopsimorpha sp., DD90VRB1_425.57m, GG13_Q19/2_(MAGNT P16021). N, Navifusa majensis; specimen perhaps in fission; DD90VRB1_413.7m, GG12_U46/4_(MAGNT P16023). O, Leiosphaeridia minutissima, DD90VRB1_419.52m, 57_M34/1_(CSR0558-010). P, Leiosphaeridia crassa, DD90VRB1_419.52m, 57_O23/4_(CSR0558-010). Q, Leiosphaeridia jacutica, DD90VRB1_413.7m, GG12_E44/2_(MAGNT P16023). R, Leiosphaeridia tenuissima, DD90VRB1_413.7m, GG12_G46/2_(MAGNT P16023). Scale bar represents: 20 μm (A, F, O–R); 50 μm (B–E, G–N).
Unnamed species I and J from the Blue Hole Formation, DD90VRB1 drillcore. A–F, unnamed species I; note granular texture and faintly banded appearance; A–B, DD90VRB1_425.57m, GG13_P48/3_(MAGNT P16021); C–D, DD90VRB1_413.7m, GG11_F41/3_(MAGNT P16022); E, DD90VRB1_413.7m, GG11_T44/4_(MAGNT P16022); F, DD90VRB1_413.7m, GG12_P42/1_(MAGNT P16023). G–H, unnamed species J; note woven texture; DD90VRB1_420.27m, GG10_H16/2_(CSR0558-011). Scale bar represents: 20 μm (A, D, E, F, H); 50 μm (B, C, G).
Riedman, L.A., Porter, S.M., Lechte, M.A., dos Santos, A. and Halverson, G.P. (2023),
Early eukaryotic microfossils of the late Palaeoproterozoic Limbunya Group, Birrindudu Basin, northern Australia.
Pap Palaeontol, 9: e1538. https://doi.org/10.1002/spp2.1538
Copyright: © 2023 The authors.
Published by John Wiley & Sons Ltd on behalf of The Palaeontological Association. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
So, another casual and unintentional refutation of basic creationist dogma and another demonstration of the lie that scientists are abandoning the TOE as the best explanation of the observable evidence.
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