Fig. 1. Transmitted-light (TL) photomicrographs of Q. magnifica from the Chuanlinggou Formation.
(A to D and K) Filaments with cells of varying length and width. (E) Four-celled filament with hemispherical terminal cell. (F and G) Filament with notably decreasing cell width toward one end. Note that (F) and (G) represent the same specimen; (F) lost the narrowest part of the filament as shown in (G). (H to J) Filaments displaying more uniformity of cell dimensions. (L) Two-celled filament with ovoid terminal cell. All specimens were handpicked from organic residues of acid maceration and photographed in wet mounts, except for (K), which was photographed from a permanent strew mount. Solid and empty gray triangles in (A), (C), and (K) indicate the longest and the shortest cells, respectively, within single filaments. tb, transverse band (interpreted as cross wall); tr, transverse ring (interpreted as partially preserved cross wall). Scale bar, 50 μm [(A) to (E), (I), (J), and (L)] and 100 μm [(F) to (H) and (K)].
(A to D and K) Filaments with cells of varying length and width. (E) Four-celled filament with hemispherical terminal cell. (F and G) Filament with notably decreasing cell width toward one end. Note that (F) and (G) represent the same specimen; (F) lost the narrowest part of the filament as shown in (G). (H to J) Filaments displaying more uniformity of cell dimensions. (L) Two-celled filament with ovoid terminal cell. All specimens were handpicked from organic residues of acid maceration and photographed in wet mounts, except for (K), which was photographed from a permanent strew mount. Solid and empty gray triangles in (A), (C), and (K) indicate the longest and the shortest cells, respectively, within single filaments. tb, transverse band (interpreted as cross wall); tr, transverse ring (interpreted as partially preserved cross wall). Scale bar, 50 μm [(A) to (E), (I), (J), and (L)] and 100 μm [(F) to (H) and (K)].
As though the abundant evidence of life on earth before about 10,000 years ago wasn't bad enough for creationists who believe the Universe and everything in it were was magicked out of nothing in 6 days around about then, a team of scientists led by led by Professor ZHU Maoyan from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NGIPAS), has now pushed the date of oldest-known multicellular, eukaryote organism back another 70 million years to a whapping 1.63 billion years before the supposed 'Creation Week'.
This would mean, if their superstition had any merit that creationists believe Earth has been around for just the last 0.0006% of the time that multicellular eukaryotes have existed on it.
And they wonder why people laugh!
The fossils were discovered in the Yanshan area of North China in the late Paleoproterozoic Chuanlinggou shale Formation which is about 1,635 million years old. The age of the fossils is constrained by a layer of volcanic ash ~40 m above the fossil horizon in the Kuancheng area, which has yielded a U-Pb zircon age of 1634.8 ± 6.9 Ma (23).
All complex life on Earth, including diverse animals, land plants, macroscopic fungi and seaweeds, are multicellular eukaryotes. Therefore, multicellularity is key for eukaryotes to acquire organismal complexity and large size, and often regarded as one major transition in Earth’s life history by scientists. However, it is still poorly understood when eukaryotes first evolved this innovation in their deep evolutionary history.
Fossil records with convincing evidence show that eukaryotes with simple multicellularity already appeared at 1.05 billion years ago, including red and green algae, and putative fungi. Older records claimed to be multicellular eukaryotes, but most of them are controversial due to their simple morphology and lack of cellular structure.
[The multicellular fossils] are unbranched, uniseriate filaments composed of two to more than 20 large cylindrical or barrel-shaped cells with diameters of 20–194 μm and incomplete lengths up to 860 μm (micrometers). These filaments show a certain degree of complexity based on their morphological variation.
MIAO Lanyun, first author
State Key Laboratory of Palaeobiology and Stratigraphy,
Nanjing Institute of Geology and Palaeontology,
Chinese Academy of Sciences, Nanjing, China.
State Key Laboratory of Palaeobiology and Stratigraphy,
Nanjing Institute of Geology and Palaeontology,
Chinese Academy of Sciences, Nanjing, China.
An important feature of Qingshania, is the round intracellular structure (diameter 15-20 μm) in some cells. These structures are comparable to asexual spores known in many eukaryotic algae, suggesting that Qingshania probably reproduced by spores.
Fig. 3. TL photomicrographs of Q. magnifica with a small round or ovoid inclusion from the Chuanlinggou Formation.
(A, C, and D) Filaments with constant width. (B and E) Magnifications of dashed boxes in (A) and (C), respectively, showing details of round inclusions. (F) Filament of notably varying width. Note that the middle cell of the filament is cyathiform in shape. (G and H) Magnifications of dashed box in (F) and (D), respectively. All specimens were handpicked from organic residues of acid maceration and photographed in wet mounts. Scale bar, 50 μm [(A), (C), (D), and (F)].
(A, C, and D) Filaments with constant width. (B and E) Magnifications of dashed boxes in (A) and (C), respectively, showing details of round inclusions. (F) Filament of notably varying width. Note that the middle cell of the filament is cyathiform in shape. (G and H) Magnifications of dashed box in (F) and (D), respectively. All specimens were handpicked from organic residues of acid maceration and photographed in wet mounts. Scale bar, 50 μm [(A), (C), (D), and (F)].
The nearest modern organisms to these ancient fossils are the green, red, brown and yellow algae, suggesting that Qingshania was probably photosynthetic and probably belonged to an extinct stem group of Archaeplastid.
At present, the oldest unambiguous eukaryotic fossils are unicellular forms from late Paleoproterozoic sediments (~1.65 billion years ago) in North China and Northern Australia. Qingshania appeared only slightly later than them, indicating eukaryotes acquired simple multicellularity very early in their evolutionary history.
The authors give more technical details in their open access paper in Science:
Abstract
Multicellularity is key to the functional and ecological success of the Eukarya, underpinning much of their modern diversity in both terrestrial and marine ecosystems. Despite the widespread occurrence of simple multicellular organisms among eukaryotes, when this innovation arose remains an open question. Here, we report cellularly preserved multicellular microfossils (Qingshania magnifica) from the ~1635-million-year-old Chuanlinggou Formation, North China. The fossils consist of large uniseriate, unbranched filaments with cell diameters up to 190 micrometers; spheroidal structures, possibly spores, occur within some cells. In combination with spectroscopic characteristics, the large size and morphological complexity of these fossils support their interpretation as eukaryotes, likely photosynthetic, based on comparisons with extant organisms. The occurrence of multicellular eukaryotes in Paleoproterozoic rocks not much younger than those containing the oldest unambiguous evidence of eukaryotes as a whole supports the hypothesis that simple multicellularity arose early in eukaryotic history, as much as a billion years before complex multicellular organisms diversified in the oceans.
INTRODUCTION
The cell is the fundamental unit of life on Earth (1). The first organisms were most likely unicellular, and numerous clades still complete their life cycles as single cells. That said, multicellularity has arisen many times within bacteria and the Eukarya (2, 3). Most of these clades comprise simple multicellular organisms, with cell-cell adhesion but limited communication or differentiation among constituent cells; complex multicellularity, with greater directed intercellular communication and more pronounced cell and tissue differentiation, has arisen only six to seven times, all within the Eukarya (2, 3).
The evolution of multicellularity is a question of history and process, and paleontological records can potentially tell us when and under what conditions multicellular eukaryotes first evolved. Fossils found on several continents show that in the oceans, simple multicellular eukaryotes, such as uniseriate filaments and coenobia, arose long before the advent of complex multicellular animals and algae (2, 3); prokaryotic multicellularity extends even further back into the Archean (4). Relatively abundant late Mesoproterozoic to early Neoproterozoic populations include forms interpreted as red [Bangiomorpha pubescens, ~1050 million years (Ma), arctic Canada (5, 6)] or green [Proterocladus antiquus, ~950 Ma, North China (7)] algae, as well as putative early fungi [Ourasphaira giraldae, ~890 Ma, Arctic Canada (8)] and eukaryotic problematica, including Eosolena loculosa [~1030 Ma, Siberia (9)], Arctacellularia tetragonala [~1000 Ma, Congo (10)], and Archaeochaeta guncho [~950 Ma, northwestern Canada (11)]. Less common records of both cellularly preserved microfossils such as Eosolena minuta from northern Siberia (12) and decimeter-scale carbonaceous compressions from North China (13) extend the record of eukaryotic multicellularity back to the early Mesoproterozoic era. If their stratigraphic placement is correctly interpreted, then phosphatized microfossils from India (14) would add substantially to this record. The coiled ribbon–like macrofossil Grypania from India not only shows clear evidence of multicellularity and large size consistent with a eukaryotic affinity (3), but it also has been interpreted as a possible giant cyanobacterium (15). Other coeval (16) and older records (17) of Grypania are more controversial because of the absence of preserved cellular structure, much like pyritic macrostructures reported from ~2.1-Ga shales in Gabon (18) and carbonaceous compressions from the ~1630-Ma Tuanshanzi Formation in North China (19), whose biological origins are uncertain.
Large uniseriate filaments described as Qingshania magnifica, with cell diameters up to 250 μm, were described as early as 1989 by Yan (20) from thin sections of shales within the late Paleoproterozoic Chuanlinggou Formation, North China, and interpreted as primitive green algae. Owing to the poor image quality of the material described and its publication in a relatively difficult-to-access journal, this report has received little attention since its publication. Here, we revisit the question of Paleoproterozoic multicellularity and report abundant, organically preserved multicellular filaments extracted from shales of the Chuanlinggou Formation in the Yanshan Range, North China. Their overall morphology and size range, as well as stratigraphic position, suggest that these filaments can be assigned to Q. magnifica. Our materials reveal conspicuous morphological details and additional characters (e.g., spheroidal intracellular structures), which, in combination with spectroscopic evidence, provide strong support for the interpretation of these fossils as eukaryotic, thus indicating that eukaryotes evolved simple multicellularity and likely, photosynthesis, early in the history of the domain.
Fig. 8. Overview of early evolution of the Eukarya along with fossil records.
(A) Simplified eukaryotic tree with divergence time estimates of major branches by molecular clock study. LECA, last eukaryotic common ancestor. Dashed gray lines represent hypothetical stem-group eukaryotes, which are extinct. Tree topology and molecular clock estimates are from (67). Abbreviation: Pha., Phanerozoic. (B) Representative fossil records of early eukaryotes. The oldest unambiguous eukaryotic fossils are unicellular forms, e.g., Tappania plana and Shuiyousphaeridium macroreticulatum from ~1650-Ma Ruyang Group [images courtesy of L. Yin, reprinted from (75) with permission from Elsevier]; Dictyosphaera macroreticulata, Germinosphaera alveolata, and Valeria lophostriata from the Changzhougou Formation and lowermost Chuanlinggou Formation in North China [reprinted from (76) with permission from Elsevier]. The Q. magnifica represents the current oldest convincing multicellular eukaryote from ~1635-Ma upper Chuanlinggou Formation in North China. The oldest red alga is Bangiomorpha pubescens from ~1050-Ma Hunting Formation, Canada [image courtesy of N. Butterfield, reprinted from (5) Cambridge Univ. Press, reproduced with permission]. The oldest green alga is P. antiquus from ~950-Ma Nanfen Formation in North China [image courtesy of Q. Tang, reprinted from (7) with permission from Springer Nature]. The oldest putative fungus is O. giraldae from ~890-Ma Grassy Bay Formation in Canada [image courtesy of C. Loron, reprinted from (8) with permission from Springer Nature]. The oldest amoebozoans are vase-shaped microfossils, e.g., Cycliocyrillium torquata from ~750 to 730 Ma Kwagunt Formation, Chuar group in Arizona [image courtesy of S. Porter, reprinted from (79) Cambridge Univ. Press, reproduced with permission]. Scale bars, 500 μm (the image of the oldest green algal fossil equals) and 50 μm (the rest).
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