POBAM 2024: Deadline Approaching

Friend of the blog Aja Watkins is co-organizing POBAM (Philosophy of Biology at the Mountains) 2024. (Missed Aja’s essay? Read it here!) The deadline for abstract submissions is coming up in a week (3/30). Here is the complete call:

POBAM 2024: Philosophy of Biology at the Mountains Call for Abstracts

University of Utah; Salt Lake City, UT

July 17-19, 2024

The POBAM Workshop showcases new, innovative, interdisciplinary and collaborative work in the philosophy of biology. Submissions can be on any topic in the philosophy of biology, biologically oriented philosophy of science, or philosophically-informed biology. 

For 2024, you may submit a proposal for either a long talk (40 min talk, 20 min Q&A), short talk (20 min talk, 10 min Q&A), long talk with pre-read (20 min talk, 40 min Q&A; note that you will be required to submit a draft of a full paper well in advance of the conference for this option), or a 5-minute lightning talk + poster. The latter option includes a poster display as well as a chance to pitch your project to POBAM participants in a special “POBAM Poster Pitch” session.

Abstract submissions may be up to 500 words and must be prepared for blind review. Please indicate in your submission whether you are applying for a long talk, short talk, long talk with pre-read, or lightning talk + poster. Also, indicate if you wish to be considered for another category of talk if you are not selected for the one you prefer.

You will also have the option to submit a proposal for a professional development session, or indicate your interest in leading one of the following sessions: (1) Networking 101; (2) How to peer review a paper; (3) Demystifying the publication process; (4) Designing inclusive classroom activities; (5) Creating and sharing syllabi; (6) What is a philosophy of biology lab?; and (7) Navigating the job market.

All abstracts must be submitted through Easy Chair.

The deadline for submission is March 30, 2024.

The Mirror of Prehistory?

There is a new article in Aeon about the role that (human) prehistory plays in making sense of the present (specifically, the nuclear age). I imagine the editors were sitting on this one for the coronation of the Anthropocene Epoch. Anyway, that ain’t happening, so here it is.

This, I take it, is the big idea:

No two eras from human history began more differently than the atomic age and the prehistoric period. And yet, despite the difference in their temporal constitution and their positions at the extremities of human time – one in the deep past, the other in the 20th century – a reciprocal analogical relationship exists between them. We have learned to imagine one through the other.

Again: “In the 20th century, prehistory constituted a symbolic field that never ceased to nourish the anxious thinking of the atomic age.”

Now go read the article and meet me after the break.

* * *

Have you read it? Super! I just finished it myself. And I'm inclined to give a big shrug. Like, is it really the case that a deep reciprocal interaction existed between prehistory and the nuclear age? Or did a few scholars in the humanities use analogies with prehistory to say stuff about, like, the totemic function of nukes and the waywardness of nuclear society? The author has some interesting examples, but I can’t shake the feeling that they add up to less than what she claims for them.

I'm also skeptical of the notion that, in the 19th century, “understanding the deep past involved imagining the ruins of humanity and ejecting Homo sapiens from the evolution of life.” What's right about this claim is what Martin Rudwick has often said: that the sciences of geohistory were born when ideas from human history were transposed into the study of nature’s own history. But then what's this business about ejecting humans from the evolution of life? Also, the passage cited in support of this observation was written by a creationist scientist in 1844.

Okay, that's enough grumpiness from me. Happy Friday!

No Anthropocene, no problem

The Holocene continues! For anyone anxious about the impending (retrospective) termination of the present geological epoch, you can rest easy. The International Commission on Stratigraphy has your back:

“The decision is definitive,” says Philip Gibbard, a geologist at the University of Cambridge who is on the panel and serves as secretary-general of the International Commission on Stratigraphy (ICS), the body that governs the geologic timescale. “There are no outstanding issues to be resolved. Case closed.”

Of course, in the wonderful world of bureaucratic science, the case is never really closed, and it remains possible that future geologists will submit another proposal to the ICS. Check back in ten years.

*Update: actually, check back now. Some advocates of the new GSSP proposal are questioning the legitimacy of the vote:

the SQS [Subcommission on Quaternary Stratigraphy] chair, Prof Jan Zalasiewicz, from the University of Leicester, said: “The alleged voting has been performed in contravention of ICS statutes. Violation of the statutory rules included those about the eligibility to vote and other vital rules for securing a due scientific process. The [leak] has exposed the SQS, and by default its parent scientific bodies, to a considerable potential for reputational damage.”

Zalasiewicz, supported by one of the SQS vice-chairs, said he had requested an inquiry “including instituting a procedure to annul the putative vote.”

For those interested in a more thorough write-up, the Science news team did a good job:

https://www.science.org/content/article/anthropocene-dead-long-live-anthropocene

And here are two Extinct entries on the Anthropocene, the first by Adrian Currie and Derek Turner, the second by yours truly:

The Future Geologist and the Anthropocene

Geological time and the philosophy of the "golden spike"

What’s in a name? What should be?

Nature recently ran an interesting piece on the absence of rigorous guidelines for naming dinosaur species. It seems to have been prompted by unpublished work by Emma Dunne and colleagues, which tries to quantify the volume of “problematic” dinosaur names in the literature. (Here “problematic” should be taken in the political sense, as indicating the presence of racist, sexist, or [neo-] colonial connotations) Dunne and colleagues found that about 3% of the names tick this box: not a large number, but not a negligible one either. In a database of ~1500 entries, it comes to about 45 names. Anyway, the ICZN is unlikely to act on this information for reasons having to do with taxonomic stability. It seems that other options are on the table, however, like a peer review process for new names in the literature.

For some related content, check out Jan Forsman’s piece on the first named dinosaur, Megalosaurus:

The Weird Early History of PaleontoloGY: ROBERT PLOT And Scrotum humanum

And also my essay on paleontology and colonialism:

Lords of Marble and the Spear

Philosophy of the Paleosciences Workshop at Egenis (Exeter)

There will be a conference on the philosophy of the paleosciences, hosted by Adrian Currie of the University of Exeter, August 12–16. The conference will take place in Exeter with a retreat along the Jurassic Coast. All travel costs for speakers will be covered. Here is the call for abstracts:

“Egenis, the Centre for the Study of the Life Sciences, will host a 2-day workshop on the philosophy of the paleosciences, followed by a 3-day retreat to the Jurassic Coast. Travel costs to Exeter and the retreat, as well as accommodation will be covered for all speakers.

Abstracts of no more than 500 words and CVs should be emailed to Adrian Currie at a.currie@exeter.ac.uk by the 1st of April. Topics can include anything related to the history, philosophy or sociology of the paleosciences, broadly construed. Get in touch with Adrian if you’ve any questions.

Invited Speakers

Alisa Bokulich (Boston University)

Max Dresow (Macalester College)

Andra Meneganzin (KU Leuven)

Derek Turner (Connecticut College)

Alison Wylie (University of British Colombia)

The Retreat will be based in the Kingcombe Meadows Nature Reserve and will involve both discussions surrounding a draft of Adrian Currie’s monograph The Science of Lost Worlds, as well as a set of extra-curricular activities on the Jurassic Coast.”

Conference: From Crisis to Coordination: Conversations Between Philosophy of Environmental Justice & Philosophy of Conservation Science

There is a conference on the intersection of the philosophies of conservation science and environmental justice taking place at the University of Minnesota this spring (May 23, 2024–May 25, 2024). Karen Kovaka, Romy Opperman, and Andrea Sullivan-Clarke are confirmed speakers. I will place the call for abstracts below.

* * *

Kyle Whyte’s “Against Crisis Epistemology” (2021) urges those concerned by climate change and for environmental justice away from a crisis epistemology and toward an epistemology of coordination. In contrast to a crisis epistemology— which is apt to intensify colonial oppression due to the assumption that present challenges are new, unprecedented, and urgent— epistemologies of coordination seek to address challenges by developing and renewing relations of kinship, expressed as moral bonds of mutual responsibility. Inspired by this recommendation toward coordination, this conference aims to promote dialogue among philosophers of environmental justice and of conservation science. We seek to discover what we can mutually cogenerate toward the common goals of stewardship and environmental justice. Central to the conference are the questions: What can philosophers of conservation science learn from those of environmental justice, and vice versa? What would coordination look like?

We aim for this conference to bring together philosophers working on environmental justice, climate change, conservation, and environmental science toward ends of coordination and collaboration and invite the submission of abstracts on these themes. Submissions needn’t cover all themes of the conference; we plan to have a robust group of participants that cover various areas and for the central morals to emerge collaboratively during our time together.

Abstracts ought to be roughly 250 words long and prepared for anonymous review. They may be submitted to Bennett McNulty (mcnu0074@umn.edu) by February 29th, 2024. We expect to review abstracts and notify submitters by mid-March.

Limited funding may be available to support graduate students, contingent faculty, and others without institutional funding. If you do not have institutional funding and would like to receive this funding, should it be available, please let us know in your abstract submission email.

Finally, for those that cannot attend in person, we will provide the option of virtual participation in the conference via Zoom.

Organisers:

Max Dresow (Macalester College)

Michael Bennett McNulty (University of Minnesota)

Ália Kel O’Loughlin (University of Minnesota)

Lauren Wilson (University of Minnesota)

Jobs in philosophy of the historical sciences

Well here’s something you don’t see every day: a job ad for philosophy of historiography and the historical sciences. Here's the full ad:

2 JOBS: Philosophy of Historiography and the Historical Sciences- Senior and Junior Research Fellowships

The two fellowship are pure research positions.  They are open to all candidates whose profiles match the above requirements.  Other than their research prospects and records, the identity of the candidates will remain behind a veil of ignorance.  Most notably, the fellowships are open to all qualified candidates irrespective of their nationalities, social classes, statuses of their universities, ethnicities, and genders.  The choice of candidates will follow strictly the quality and quantity of prospective future research in the philosophy of historiography and the historical sciences. Knowledge of the Czech language is not required, but successful candidates will be encouraged to acquire the language during the years of their fellowship.  The University of Ostrava will assist in providing Czech language courses. The prospective salaries suffice for comfortable living in the Czech Republic for an applicant and her or his immediate family and include health insurance and other benefits.  While the fellowships guarantee income for four years subject to satisfactory progress in research efforts, the research team will attempt continuously to secure further grants to preserve, sustain and perpetuate its mission beyond this time horizon.

The successful candidates will be affiliated with the Department of Philosophy at the Faculty of Arts, the University of Ostrava. The Department’s staff pursue a broad range of research interests, including metaphysics, logic, ethics, aesthetics, political philosophy, philosophy of religion, philosophy of nature, and the history of philosophy (ancient, medieval, modern, & contemporary)).

The successful candidates will further become members of the Centre for the Philosophy of Historiography and the Historical Sciences at the University of Ostrava – a new research centre, led by Aviezer Tucker and David Cernín. See the Centre’s Web page at: https://ff.osu.eu/phil-hist/

Ostrava is the second largest urban conglomeration in the Czech Republic/ Chechia.  The cost of living in Ostrava is significantly lower than the European Union average.  Ostrava has frequent, regular, pleasant and cheap train links to Prague, Vienna, and Cracow that take 3-4 hours, and an international airport with regular flights to airports in and out of Europe, including London and Warsaw.  Ostrava has a vibrant art and culture scene, including the summer “Colors of Ostrava” international performing arts festival and the world-famous Janacek Symphony Orchestra.  

1. Senior Research Fellowship R3 (cf. https://euraxess.ec.europa.eu/europe/career-development/training-researchers/research-profiles-descriptorsin) in the philosophy of historiography and the historical sciences for 4 years. 

Requirements:

• At least five years past the PhD. 

• At least 8 publications indexed in the Web of Science and/or SCOPUS databases and/or 2 monographs);H-index (WoS or Scopus) of at least 2 or Scholar 4 or at least 35 citations.

• Proven ability to publish high quality research in the philosophy of historiography and the historical sciences in English.

• Readiness to initiate and participate in grant applications.   

To Apply:

• Submit by October 27 to PersonalniFF@osu.cz ; please, follow the guidelines at https://www.osu.eu/job-opportunities/?kdepr=0&prace=2430

• Four years research proposal and plans in the philosophy of historiography and the historical sciences of up to five pages;

• Brief cover letter;

• Curriculum vitae;

• List of publications, highlighting the candidate’s two best publications in the philosophy of historiography,

• Scanned copy of the PhD diploma;

• Nominal-formal consent to the processing of personal data (as required by EU regulation); the required form is available at https://dokumenty.osu.cz/osu/uredni-deska/personalistika/consent-to-data-processing.docx

2.       Junior Research Fellowship R2 (cf. https://euraxess.ec.europa.eu/europe/career-development/training-researchers/research-profiles-descriptorsin) in the philosophy of historiography and the historical sciences for 4 years. 

Requirements:

• Candidates should have received their PhD at least five years ago,  but excellent well published candidates who graduated less than five, but more than three years, ago will be considered

• The candidate should have at least 4 publications indexed in Web of Science or Scopus databases and/or one monograph);H-index (WoS or Scopus) of at least 1 or Scholar 3, or at least 20 citations.

To Apply:

• Submit by October 27 to PersonalniFF@osu.cz ; please, follow the guidelines at https://www.osu.eu/job-opportunities/?kdepr=0&prace=2429

• Four years research proposal and plans in the philosophy of historiography and the historical sciences of up to five pages;

• Brief cover letter;

• Curriculum vitae;

• List of publications highlighting the candidate's two best publications in the philosophy of historiography

• Scanned copy of the PhD diploma;

• Nominal-formal consent to the processing of personal data (as required by EU regulation); the required form is available at https://dokumenty.osu.cz/osu/uredni-deska/personalistika/consent-to-data-processing.docx

For more details see:

https://www.osu.eu/job-opportunities/?kdepr=0&prace=2430

Job Opportunities / University of Ostrava

Ships that pass in the Night

Today is Stephen Jay Gould's birthday. Were he still alive, he would be eighty-two years old. As it happened, he died in 2002 when he was only sixty.

As if to commemorate this occasion, a paper appeared yesterday in Nature Communications (“Bayesian Analyses Indicate Bivalves did not Drive the Downfall of Brachiopods Following the Permian-Triassic Mass Extinction”). In a nutshell, it is a Bayesian analysis of diversification dynamics in brachiopods and bivalves, using data from the Paleobiology Database. Here is how the authors describe the study:

First, we estimate the origination and extinction rates, and diversity of the post-Cambrian brachiopods and bivalves using fossil occurrence data from the Paleobiology Database (PBDB). This analysis shows the long-term pattern of their diversification history and highlights the importance of the Permian–Jurassic interval in assessing the brachiopod-bivalve switch. We then exhaustively revise the taxonomy and stratigraphy of the global fossil record of Permian–Jurassic brachiopods and bivalves and use these bespoke datasets to examine the dynamics of the brachiopod-bivalve switch at high temporal resolution, with emphasis on differences between ecological guilds and geographical regions. Finally, we use a multivariate birth-death model (PyRateMBD38) to evaluate the potential factors driving the extinction and recovery of brachiopods and bivalves across the [Permian-Triassic mass extinction]. (Guo et al. 2023, 1)

What does this have to do with Gould? In 1980, Gould and C. Bradford Calloway published an article called, “Clams and Brachiopods—Ships that Pass in the Night.” The allusion is to Longfellow, who wrote of “Ships that pass in the night, and speak each other in passing; Only a signal shown and a distant voice in the darkness.” What Gould and Calloway tried to show was that clams and brachiopods spoke to each other only in passing; that in spite of the fact that brachiopod decline roughly tracked bivalve diversification, the case for competitive displacement was thin. Instead, the “supposed replacement of clams and brachiopods” was produced by a single event, the Permian-Triassic mass extinction, “which affected brachiopods profoundly and clams relatively little” (Gould and Calloway 1980, 383). From this they concluded that “passive extrapolation of microevolutionary theory into the vastness of geological time [often leads] paleontologist astray.” Although competitive interaction “may rule in local populations,” differential response to mass extinction “[sets] the relative histories of large groups through geological time. Similarly, adaptive superiority and design cannot have much to do with the macroevolutionary success of clams.”

Gould and Calloway’s argument was influential but hardly decisive. As Guo et al. report, “the decline of brachiopods after the PTME has [subsequently] been attributed to intense predation, decreased ability to expand habitat distribution, or increased energy flux”(Guo et al. 2023, 2). All these scenarios imply the competitive replacement of brachiopods by bivalves. But the new analysis favors the Gould/Calloway scenario. As the authors write: “Insight from a multivariate birth-death model shows that the extinction of major brachiopod clades during the PTME set the stage for the brachiopod-bivalve switch, with differential responses to high ocean temperatures post-extinction further facilitating their displacement by bivalves. Our study strengthens evidence that brachiopods and bivalves were not competitors over macroevolutionary time scales, with extinction events and environmental stresses shaping their divergent fates” (Guo et al. 2023, 1).

“So on the ocean of life we pass and speak one another; Only a look and a voice, then darkness again and a silence.” Happy birthday, Gould.

A golden spike for the Anthropocene

Yesterday, the Anthropocene Working Group proposed that the “golden spike” for the Anthropocene should be symbolically driven into a sediment core extracted from Crawford Lake in Ontario. A “golden spike” is a point in the stratigraphic column that serves as the official marker for the start of a time period, in this case, the proposed (but not yet ratified) Anthropocene epoch. The Anthropocene has been controversial, for reasons previously debated on this very blog. I find myself in sympathy with what Jacquelyn Gill recently told a reporter from Nature:

The work to define an age of human impacts has taken “a tremendous amount of effort, to solve a problem that I don’t think exists” … “We all already know what we mean when we say the Anthropocene.”

Still, others maintain that the ratification of the Anthropocene is a matter of political importance, and moreover, that failure to ratify it might have undesirable political consequences. (See the linked article from friend of the blog Hernán Bobadilla.)

You can expect more soon from Extinct on the golden spike announcement. [Update: follow this link.]

A very problematic problematic fossil

Problematic fossils were once a major problem in (especially invertebrate) paleontology. It was the kind of problem for which conferences were convened and edited volumes organized. One such volume, edited by Alberto Simonetta and Simon Conway Morris, begins thus:

Problematical taxa are one of the most intriguing, and most ignored, of the problems in biology. The tendency to relegate them to the sidelines of enquiry, and the dustbin of classification, is understandable, but such treatment threatens to remove an area of great interest to evolutionary biology.

In short, problematica were really quite problematic, and the problems they raised struck many as important ones.

The volume I just quoted from appeared in 1991, at the high point of paleontological distress about problematic fossils. Since then, things have cooled off considerably. The reason is that many problematica have found a home in the stems of living groups: a solution that splits the difference between the old solutions of (1) erecting a new high-level taxon to accommodate the aberrant form, or (2) “shoehorning” the fossil into a living taxon (meaning a crown group). Doug Erwin summarized the new attitude at the recent MBL-ASU History of Biology Seminar. Once a source of great difficulties, the outstanding Cambrian problematica are now the sort of thing you “give graduate students [to figure out].” In Kuhnian language, problematica have shifted from being anomalies to being mere puzzles.

There is one major exception to this trend, however, and that is the Tully monster. A comical animal with stalked eyes and a long proboscis, fossils of Tullimonstrum gregarium are known only from the Upper Carboniferous Francis Creek Shale of Illinois. Yet here they exist in great abundance. The first fossils of the Tully monster were discovered in 1966. Since then, the animal has been compared to a gastropod, conodont, polychaete, nemertean, and nectocarid, to name a few groups. It has also, more recently, been assigned to the vertebrates: a placement that seemed to receive a decisive confirmation with the recent report of a notochord, along with “cartilaginous arcualia, gill pouches, articulations within the proboscis, and multiple tooth rows adjacent to the mouth” (McCoy et al. 2016, 496). (These features conspired to place Tullimonstrum on the lamprey stem, based on an analysis of over 1,200 specimens.)

But recent work by a team of Japanese paleontologists casts doubt on this identification. This team, led by Tomoyuki Mikami of the National Museum of Nature and Science in Tsukuba, performed high-resolution 3D scans of more than 150 Tully monster specimens, along with x-ray micro-computed tomographic analysis of the stylets (mouthparts). What this revealed was that several features previously interpreted as signs of vertebrate ancestry are not comparable to those in vertebrates. These include the Tully monster’s tri-lobed brain, tectal cartilages, and fin rays. More damaging, Mikami and colleagues showed that Tullimonstrum’s body segmentation differs from that the vertebrate pattern in extending from the preoptic head region to the tail. In their words, “no known vertebrate lineage has ever shown a preoptic segmented structure contiguous with somatic segmentation” (Mikami et al. 2023, 5). This suggests that “[the] body segmentation of Tullimonstrum probably reflects a non-sclerotized, possibly internal structure,” consistent with the interpretation that the Tully monster is either a non-vertebrate chordate or a protostome.

A specimen, scan, and interpretive drawing of Tullimonstrum (from Mikami et al. 2023)

Just what was Tullimonstrum? That remains to be definitively established. In the meantime, it is a fine thing that this creature has kept its secret through a half-century of research, now powered by x-ray tubes and particle accelerators, and pursued by scientists all over the world.

Forthcoming event: Boston Colloquium on Philosophy of the Geosciences

Attention Extinct readers! There is a fantastic two-day event coming up on May 5th and 6th. That’s a Friday and a Saturday. It is taking place at Boston University but is fully hybrid. Here is your link to register: https://www.bu.edu/cphs/

Extinct founder Derek Turner will be speaking on day 1, along with recent contributor and friend of the blog Aja Watkins. Another recent contributor and friend of the blog, Federica Bocchi, will be speaking on day 2. They are surrounded by a who’s-who in the philgeo community, including some founding members (Rachel Laudan, Robert Frodeman, Carol Cleland). There is also a good showing from historians of the geosciences, including past Extinct contributors David Sepkoski and Lukas Rieppel. Check it out!

Give and take

We’ve talked before about the importance of comparative reasoning in anatomical reconstruction. (Please read “Problematica”!) Well, it just so happens that there have been some splendid examples in the news lately.

The first comes from the journal Diversity, where Russell Engelman of Case Western University just chopped Dunkleosteus in half relative to previous estimates of maximum body length. Dunkleosteus, if you don’t know, is an armored placoderm hailing from the Late Devonian. It has, I submit, the ugliest mug of any fish in the fossil record. (For real. Check this thing out.) Previous best guesses placed its maximum length around 5–10 meters, with most estimates settling near the upper end of that range. But according to Engleman, this is too high. His claim is based on a new proxy for body size: orbit-opercular length, which corresponds to the distance between the anterior margin of the eye socket and the posterior margin of the head. The measure fulfills three desiderata for a body length proxy for Dunkleosteus: (1) it accurately measures body length across fishes in general, (2) it is measurable on arthrodire* fossils, and (3) it accurately predicts body length in complete arthrodire specimens. (Arthrodira is the group that includes Dunkleosteus.)

The results of Engleman’s analysis are most vividly expressed in the graphical abstract reproduced above. If you prefer it in writing: large arthrodires like Dunkleosteus “were much smaller than previously thought,” with the largest known individuals probably reaching lengths of no more than ~4.1 meters (13.5 feet). Moreover, “[the] length estimate for Dunkleosteus… result in an animal with a very deep and wide body relative to its total length.” (#Chunkleosteus) This body type is consistent with other arthrodires whose proportions can be more directly figured, but even still Dunkleosteus is an “extremely girthy” outlier. Nothing like it exists in the present oceans, although lungfish, coelacanths, and tuna provide the closest living analogs.

At this point you might be justifiably upset that reanalysis tends only to diminish the size of iconic paleontological monsters. (This is the third example of this phenomenon I have discussed, in addition to the two in this installment of “Problematica.”) But happily, a reanalysis of the sauropod Mamenchisaurus sinocanadorum demonstrates the expansive power of the practice. M. sinocanadorum is known from a single specimen, and this a highly incomplete one. Yet fortunately for researchers, the probable sister taxon of M. sinocanadorum provides a useful model for estimating the length of its neck.

Life reconstruction of M. sinocanadorum. Credit: Júlia d’Oliveira

Here’s where things get fun. The sister taxon, Xinjiangtitan, has the longest preserved neck of any known vertebrate, measuring just under 13.5 meters (about 44 feet). For comparison, that’s about the length of an adult male humpback whale. But based on “functional centrum length measurements” (which measure the distance between the two points at which a centrum articulates with an adjacent centrum), researchers were able to derive a simple scaling factor that puts the M. sinocanadorum neck at 14.4 meters! When they further adjusted the figure to factor in allometry, this jumped to 15.1 meters (nearly 50 feet), which they describe as a “conservative” estimate. As Jack Tamisiea* observes, “This would account for roughly half of its estimated total body length and is equivalent to just over eight giraffe necks stacked end-to-end.”

[* Jack Tamisiea has you covered. Here is his story on Dunkleosteus.]

Reanalysis is not simply an exercise in diminution, then. The Lord giveth and the Lord taketh away: and so it goes with paleontology.

Treasure trove from the Early Triassic

How did life respond to Earth’s greatest mass extinction? This is the subject of a new study in Science.

First some background. It has long seemed that the Early Triassic was a relatively boring time in the history of life, dominated by those “weedy” species that made it through the end-Permian catastrophe. A popular model of ecosystem recovery imagined a gradual refilling of the trophic “bucket,” beginning with the lowest levels and proceeding to higher and higher ones. The matter has remained obscure, though, in virtue of the death of lagerstätten from the earliest Triassic. (Lagerstätten provide privileged windows into the structure of past ecosystems. So, the dearth of lagerstätten from the earliest Triassic makes it difficult to assess the extent of trophic diversity during the first three million years of this period.)

But ask and you shall receive—or at least that’s how it seems to work in the rocks of South China. Back in 2015, paleontologist Xu Dai discovered the oldest Mesozoic lagerstätte in a succession of rocks near Guiyang. It dates to about a million years after the end-Permian extinction, and bursts with fish, shrimp, lobsters, ammonoids, sponges, conodonts and forams. This is a genuine treasure trove, which suggests a more rapid recovery from the end-Permian extinction than has previously been entertained. Maybe it was the case that more occupants of high trophic levels dodged the Permian extinction than we thought. Or maybe important elements of the modern marine fauna radiated quickly, despite inhospitable conditions in the earliest Triassic. At any rate, it seems that notions of a slow and stepwise recovery are no longer adequate. The story of earth’s greatest extinction just got more interesting, again.

For those interested in a quicker read, here’s a write-up from the news team at Nature (also, sadly, paywalled).

Oily blobs from the underworld

How many nails must be pounded into a coffin before it ceases to spring open? Find out now, in Science Advances!

Defenders of the biogenicity of the ~3.5 Ga Apex chert “microfossils” have been fighting a rearguard action since 2002, when Martin Brasier and colleagues published a damning reanalysis of the specimens and their geological context. These specimens were once thought to be the oldest known fossils in the fossil record. William Schopf, who described the specimens in a celebrated paper, claimed that they occurred in a sedimentary bedded chert, and more spectacularly (since they greatly predate evidence for significant oxygenation) that they may have been related to oxygen-producing cyanobacteria. But Brasier and colleagues showed that the specimens most likely originated in a hydrothermal setting, ruling out a cyanobacterial interpretation. They also showed, for example, that parts of the original specimens were cropped out of the published photographs (and not represented in the accompanying interpretive drawings), all of which led them to conclude that the putative fossils were in fact abiotic structures that formed around recrystallizing mineral grains during a series of hydrothermal events.

I am going to write about the Apex chert sometime, because what I have related is only the beginning of the story. But from my extreme outsider’s perspective, it seems that Brasier and friends gained the upper hand in 2002 and never relinquished it. (Martin Brasier died tragically in 2014, when a severely overtired man fell asleep at the wheel and collided with Brasier’s car. It is an extremely sad story, not least because it is impossible to read about the circumstances of the accident and not feel sorry for the man who caused the crash.) Anyway, this new publication is the latest chapter in the now thirty-year saga of these probably-not-actually-fossils. It argues that the carbon associated with the specimens is not biological in origin. But it also raises a question: where did the organic molecules in the chert come from? One possibility is from a reaction between water and rocks, an intriguing suggestion that nonetheless does not exclude the possibility that life existed during this time.

For the full story, follow the link above to the open-access article. A more accessible write-up can be found here.

A "Neo-Gouldian" argument for evolutionary contingency

The route from acceptance to publication is BJPS is a long one. As a result, there are many papers that are in the queue, waiting to be assigned an issue.

One that is nearing the front of the queue is this contribution from T.Y. William Wong, called “The Neo-Gouldian Argument for Evolutionary Contingency.” It is happy timing, since it was recently announced that the next MBL-ASU History of Biology Seminar will be called “Replaying Life’s Tape: Historical Contingency in the Life Sciences.”

Very roughly, the paper seeks to update Gould’s arguments about the contingency of life’s history in light of recent studies of Cambrian disparity and the selectivity of mass extinctions. I should say that this description is based entirely on the abstract: I haven’t had a chance to read the paper yet. But it seems likely to be interesting to readers of this blog.