We have another successful thesis defence from our lab! Congrats to newly minted Dr. Kai Zhou on the successful defence of his PhD thesis.
Kai studied carbonate ichnology of the upper Miocene complex of the Las Negras area, Almeria, southeastern Spain, within a paleoenvironmental and sequence stratigraphic framework.
We are excited to see where you take your career. Congratulations on this monumental achievement!
Written by Jack Milligan
A new paper was published in Nature Ecology and Evolution by Dr. Claire Browning and co-authors, including our own Dr. Gabriela Mángano and Dr. Luis Buatois, examining trace fossils of a meiofaunal ecosystem that flourished in the immediate aftermath of the end-Ordovician extinction event (444 million years ago).
The trace fossils studied in this paper come from the Soom Shale Lagerstätte, South Africa. Three-dimensionally preserved ichnofossils, including two burrow/trail morphotypes and microcoprolites, were scanned using micro-computed tomography. These trace fossils are attributed to a low-diversity meiofaunal benthic community, dominated by nematodes and foraminifera. The ichnofossils are preserved in and consistently occur within fossilized marine-snow-bearing beds. Marine snow describes episodic deposition of organic material, including phytoplankton and phytodetritus, generated when wind-blown dust particles are then bound together with phytoplankton blooms in the surface water. The Soom Shale Lagerstätte provides a remarkable insight into one of the oldest meiofaunal trace-fossil records, and the earliest account of an ancient behavioural response to episodic marine snow deposition.
Check out Clarie Browning’s blog post about this research on Springer Nature Research Communities, and read the paper in Nature here.
Written by Jack Milligan
Dr. Romain Gougeon, Dr. Gabriela Mángano, Dr. Luis Buatois, Dr. Guy Narbonne, Dr. Brittany Laing, and Dr. Maximiliano Paz have just published their research on bioturbation at the onset of the Cambrian Explosion within the monograph series Fossils and Strata. This is the culmination of 4 field seasons that took place from 2016 to 2021 at the Cambrian-type section in Newfoundland. The monograph consists of a comprehensive ichnotaxonomic review that is essential to understanding the Cambrian explosion from a trace-fossil perspective.
Romain Gougeon and colleagues conducting fieldwork in Newfoundland, Canada. See Fossils and Strata for open access monograph.
The Chapel Island Formation is a 1000+ m-thick, mainly siliciclastic succession that is well-exposed in coastal cliffs of Burin Peninsula, southeastern Newfoundland, eastern Canada. This unit contains an outstanding record of the transition from the Ediacaran (635–538 Ma) to the Cambrian (538–487 Ma). Fossils from the Chapel Island Formation include an incredible diversity of trace fossils, with some intervals rich in small shelly fossils. The monograph integrates sedimentologic and ichnologic information for the whole formation, reinforces the status of the current Cambrian Global Stratotype Section and Point for the Cambrian System, and advocates for the need for more comprehensive and multi-disciplinary approaches and studies to fully decipher the scale, tempo, and loci of the early evolution of animal life on Earth.
Congratulations to Romain and the team on this incredible achievement! You can check out Romans’ ResearchGate profile here, where you can read other studies he’s authored on the Chapel Island Formation throughout the years. These include the origin of the shelf sediment mixed layer and the impact of outcrop quality on trace fossil datasets.
Written by Jack Milligan and Romain Gougeon
Former Ichnoplanet students Martín Farina, Verónica Krapovickas and co-authors have published a study on mammalian trackways from the Neogene Vinchina (Middle to Late Miocene) and Toro Negro (Late Miocene to Early Pleistocene) formations, in the La Rioja Province Vinchina Basin, Argentina!
Northwestern Argentina has an outstanding ichnological record of the Cenozoic vertebrate faunas. This study reports five mammalian trackways and the diversity of the trackmakers responsible. Of the four ichnospecies identified, three are new. The trackways come from deposits interpreted as floodplains of both meandering and anastomosed fluvial systems.
Pichipoda is a novel ichnogenus that has a didactyl to monodactyl manus and tridactyl mesaxonic pes impressions with robust digits with blunt tips. Two ichnospecies are assigned to Pichipoda, including P. manganae and P. vizcainoi. P. manganae (P. manganaei) is the largest ichnospecies of Pichipoda and has a didactyl manus, and the manus of P. vizcainoi shows an almost monodactyl morphology. Tridactylonicha marsicanae is another novel ichnogenera and ichnospecies, described by a tridactyl to didactyl paraxonic manus and tridactyl mesaxonic pes impression with long, slender, and pointed tips of the toe impressions. Dolichotichnus marae has tetradactyl paraxonic manus and tridactyl mesaxonic pes impressions.
P. manganae and P. vizcainoi are interpreted as being produced by armadillos, with P. vizcainoi being attributed most likely to tolypeutines. Before this study, ichnofossils attributable to fossil armadillos were unknown, meaning this is the beginning of our understanding of the trace fossil record of this group and can help us to ask further paleobiological questions. T. marsicanae is interpreted as being produced by hegetotheriids, a family belonging to the extinct group of South American ungulates, the Notoungulata. D. marae is most likely produced by dolichotines, a group of caviid rodents.
Astute readers will notice the etymology of P. manganae honours our very own Dr. Gabriela Mángano, which we here at Ichnoplanet firmly endorse. The contributions Dr. Mángano has made to ichnology are unmatched, and it is fitting that these newly described trace fossils act as a reflection and reminder of her great career.
Congratulations to the authors, including Martin and Verónica, on this amazing study. We know the continued research into the small mammal trackways of Cenozoic Argentina is filling in an important gap in our understanding of vertebrate faunas within South America, and we await what new discoveries have to say.
Read the paper in the Journal of South American Earth Sciences here.
Written by Jack Milligan
Dr. Buatois was featured in a new Nature article, where he commented on recent work done by the Palaeoburrows Project based at the Federal University of Rio Grande do Sul in Porto Alegre, Brazil.
In conjunction with the University of the Extreme South of Santa Catarina (UNESC) in Criciúma, Brazil, paleontologists and archaeologists have been studying a series of massive caves that have had multiple architects and inhabitants during the Pleistocene. The caves are found within a consolidated eolian sandstone unit of the early late Cretaceous Botucatu Formation (100 Ma). This makes the sandstone soft enough to burrow through and consolidated enough that the caves wouldn’t collapse.
The walls of the caves preserve large claw-like markings, as well as inscriptions and graffiti by ancient and modern humans, respectively. The large claw-like marks on the walls of the cave point to the original inhabitants of the cave, proposed to be giant ground sloths. They would construct these burrows for multiple reasons, including potentially to sharpen their claws and to seek refuge from megafaunal predators.
These would be not only the largest palaeoburrows, but the largest trace fossils known so far. From this research, a novel ichnogenera and two novel ichnospecies were named, Megaichnus minor and Megaichnus major. These palaeoburrows are so far known from Brazil and Argentina, and are attributed to giant ground sloths like Scelidotherium and Glossotherium. Work is ongoing to refine the classification scheme for palaeoburrows, conservation, and opportunities for international collaboration on future studies.
Paleoartist reconstruction of extinct giant ground sloths and armadillos by Renato Pereira Lopes.
You can read the original study in Ichnos and the news feature in Nature. Listen to a Radio-Canada interview (in French) where PhD student Dmitri Ponomarenko comments on these spectacular paleoburrows here.
Written by Jack Milligan
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