I got a request via ResearchGate to give feedback to a recently published palaeobotanical monograph. I'd love to, but I can't, really; I'm simply not qualified. But I can give some tips how to enrich a description of a palaeoflora to put palaeobotany in a better light.
Let's be frank. Palaeobotany is a fringe-science laughed at by neontologists, or worse, just ignored. Our research is hardly taken seriously, because it's mostly descriptive and methodologically boring. Proof of point are the far too many of dating and plant biogeographic papers, including top-tier journals, that are at odds with the fossil record and, in not a few cases, the tectonic-climatic past of our world.
One can't blame this (solely) on the neontologists; a main reason for their negligence is that palaeobotany doesn't engage with them and their results. Palaeobotanical monographs are not only a lot of work but usually contain a huge wealth of information vital to neontological research but it's simply not made apparent.
Thus, I did answer the request (privately), which is (for the most part) reprinted here.
I would be very happy to give feedback to any interesting collection of fossils but I'm simply not qualified.
Note that I only (well, mostly) analysed palaeobotanical data during my career but worked very little with actual fossil material. I'm just a phylogeneticist and data analysist that helped the real palaeobotanists to put their material and data into an evolutionary context. The fossil (or taxonomic) experts are the first authors of any palaeobotanical or systematic-botanical paper I co-authored. This may be unusual, usually the first authors are the molecular guys, the analysists. But I always felt that the person who collected the actual data and did most of the work has to be first author, not the person who knows how to press the right buttons on a computer. I also left the writing of introductions and discussion mostly to them, because they knew their plants. My job was usually to get results and fancy them up in an appealing, even eye-catching way, and engage when there was conflict/ were surprises, so we could find out why.
|Fossils are invaluable sources of information. Let's show exactly that!|
Nonetheless: some general tips to palaeos
I do have some general tips. Something easy to add but too rarely done in palaeobotany, which would increase the general interest in palaeobotanical monographs/ taxonomic papers. Papers representing usually are a lot of work but extremely underappreciated by the scientific community.
Show what you have found in one figure
When you work with nicely preserved and rich fossil assemblages – especially from crucial time frame frames such as the Paleocene or Eocene, the time when many modern temperate angiosperm genera evolved and started to radiate – I would always show a doodle of a recent dated tree.
Given the taxonomic breadth of high-diverse floras: an all angiosperm dated tree pruned down to orders, maybe families in particularly interesting cases (e.g. for Fagales). Then just map the fossils one found into that tree so the readers can see how well they fit (or not). A template how this can look like can be found in fig. 2 of this paper:
Grímsson F, Grimm GW, Zetter R, Denk T. 2016. Cretaceous and Paleogene Fagaceae from North America and Greenland: evidence for a Late Cretaceous split between Fagus and the remaining Fagaceae. Acta Palaeobotanica 56:247–305.
|A coloured, updated version of Grímsson et al. (2016), fig. 2|
Our 2016 paper is, essentially, "just" a systematic-taxonomic paper but realising the general relevance of our fossils, we didn't stop with the description ("Systematic Palaeobotany" section) but put them into a general framework. Here: simply comparing the place and age of our fossils with the current molecular synopsis of the group and published dated phylogenies.
For the fun of it, I also included a re-analysis of the Fagales data used by Li et al. (2004; see Grímsson et al. 2016, fig. 1), which is still the basis for the Fagales phylogeny (A solved a decade ago...). Any palaeobotanist can have the same. Tabulating age estimates from papers doesn't require any special knowledge about dating. For a bit more, just contact your local neontologists and ask for a Master or Ph.D. student interested in a little side project. Or, when picking the next Master/Ph.D., why not pick one that knows how to use or is interesting in, e.g., R. Recognising fossils requires profound long-term training (and a certain talent), there are no short-cuts. But harvesting and re-analysing available molecular data just needs some scripting skills these days. Running a standard analysis, astonishingly little skills at all; thanks to dedicated programmers trying to make their softwares idiot-proof and maintain active communities such as BEAST, IQTree and RAxML-NG.
Picking the cherries: Do I have fossil that could be game changers?
As I experienced first-hand, not a few of our foremost palaeo-alpha males think molecular dating (or any molecular data-based analysis) is "flim-flam", "nonsense", "useless", etc. There is a bit of truth to it but not because it is, but because people of their format (and insane influence within palaeobotanical circles) don't engage in it! And when they do, it's – scientifically speaking – bullshit (Wilf et al., Science, 2019; Surviving parsimonists...). Luckily, there is a generation growing up including people having an open mind and fancying getting away from the dead-beaten track of the Old Unwise Men (but still too many are caught in their webs; interesting parallel to the current political situation: old men with 80s-philosophies blocking any development).
|Unrepresentative fossil = house-number |
|Fossil close to the molecular tree's MRCA = sensible minimum estimate|
Finding and describing fossils that give new, better age constraints, a more comprehensive picture of past distribution, is pretty much the only high-valued currency palaeobotany has to offer to the rest of science.
One can't blame (solely) neontologists for publishing house-numbers — a classic is: Miocene radiation for genera that can be traced back to the Eocene, as evidenced by any well-done monograph of an Oligocene, Eocene and even Paleocene flora. When reading primary palaeobotanical literature, it's very rare to see even the slightest discussion of/ comparison with neontologist's results even when the described fossils proof them wrong. As palaeontologists, we don't need to understand how molecular dates were generated, if the age estimates are challenged by the mere existence of our fossils. Nonetheless, even experienced palaeobotanists shy back from pointing out the obvious. So, neontologists can only discuss their results compared to other equally biased, equally outdated earlier reconstructions. Note that not all but many studies rely on the same fossils, handed from one molecular dating paper to the next, none of which was reviewed or critically accompanied by somebody with an idea about the fossil record of the studied group, its factual history.
Given the insane amount of neontological papers published – now fuelled by easy-to-collect and speedy-to-analyse Big Data – how can we find the dates, we need to discuss at hand of our new (or reinterpreted) fossils? How to identify potentially precious fossils?
- Steven's Angiosperm Phylogeny Website is a most comprehensive resource to find the latest papers and dates for any angiosperm group.
- For more specific inquires, check: http://www.timetree.org/
Try for instance the pair Pterocarya, a Juglandacea, and Castanopsis, a crown-Fagaceae; the "most-recent common ancestor" (MRCA) of the two gives you estimates for the split between Fagaceaeae and most other Fagales (except Nothofagaceae): the stem-age of Fagales.
|TimeTree query 29/10/2020 for MRCA of Pterocarya (Juglandaceae) and Castanopsis (crown-Fagaceae)|
A nice spread of estimates from 105 Ma (Ma = Mega-annum = 1 million years [myrs]), to insanely young 25 Ma (black dots refer to individual studies). The collectively preferred estimate "Estimated tiem" (KT boundary–Danian) is at least 20 myrs too young. As shown above, the modern Fagales were diverged 80 myrs ago. This divergence represents the Fagales crown-age, thus, the stem-age must be older. Only the plotted oldest estimates, hence, the median time, may be close to the truth – even though being largely based on suboptimal data (prone to sampling issues).
Why is this important for palaeobotanical papers? It doesn't matter for the paper, but it does matter for its value beyond palaeo-taxonomy. There is no rule that says systematic palaeobotanical papers should be merely self-evident and otherwise utterly unsexy!
There's a demanding market to sell this particular kind of fruits. Even somebody with my limited fossil knowledge directly sees that the age estimates collected by TimeTree demonstrate a huge number are still much too young. Expectedly, one should add: Commonly applied node dating provides absolute minimum estimates and we usually lack the data to test how minimal they are (The most common errors regarding node dating).
Whenever you monographed a fossil flora, it's worth checking how many of your fossils are "too old" or close to the oldest estimates in dating literature. Those ones need to be highlighted and over-featured. And advertised as dating constraints.
One way to do so could be using a service by Palaeontologica Electronica, the fossil calibrations database.
However, last additions were 2016; after that the journal published numerous monographic/ taxonomic papers, none of which included notable dating constraints? Hard to believe.
Think of making an additional little paper. We all claim that quality is the essence of science, but career-wise, quantity beats quality. Impact-wise: when you reached a certain quantity, your measured "quality" automatically increases, too (The stag cracked the 30).
And if you have new oldest/very old records in your flora, why not reach out and recruit a data analyst or keen young computer-affine person to do some dating on your own? Keep in mind, as palaeontologist you know what you're working with, so there's no need your dating buddy has any idea about the studied organism.
|A chronogram from a paper with a palaeo-palynologist as first author (Grímsson et al. 2017, open access and open data).|
You have new oldest fossils? Hire somebody harvesting gene banks and do a dating (it's really easy and quick if you know how). Even with respect to all data-wise shortcomings, still better than leaving it to data-ignorant neontologists that, in spite of better molecular data, have failed again (Trivial but illogical...)
Put your fossils in a more general context
Even if one focusses on one sort of fossils, macrofossils, mesofossils or microfossil, one should consider the known fossil record of the respective time and area (e.g. as a short discussion paragraph) to give the paper are broader, more general appeal. A (maybe a bit too much) but outstanding example are the the Lavanttal papers by Grímsson et al. (2010–2020+): in the discussion of each described fossil taxon you are pointed to earliest records to give the reader a general idea. Where feasible, we did discuss neontological data/ relevance, too, even build up on an earlier palaeo-ecological concept (see Pt IV and V; all open access).
- Grímsson F, Zetter R, Baal C. 2011. Combined LM and SEM study of the Middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin, Austria: Part I. Bryophyta, Lycopodiophyta, Pteridophyta, Ginkgophyta, and Gnetophyta. Grana 50:102–128.
- Grímsson F, Zetter R. 2011. ... Part II. Pinophyta (Cupressaceae, Pinaceae and Sciadopityaceae). Grana 50:262–310.
- Grímsson F, Meller B, Bouchal JM, Zetter R. 2015. ... Part III. Magnoliophyta I – Magnoliales to Fabales. Grana 54:85–128.
- Grímsson F, Grimm GW, Meller B, Bouchal JM, Zetter R. 2016. ... Part IV. Magnoliophyta 2 – Fagales to Rosales. Grana 55:101–163.
- Grímsson F, Bouchal JM, Xafis A, Zetter R. 2020. ... Part V. Magnoliophyta 3 – Myrtales to Ericales. Grana 59:127–193.
Each volume so far was a huge work, but when you look at the access and download statistics, this work is appreciated by thousands of people in the scientific community (which necessarily includes neontologists, given how few palaeobotanists are left). However, only a tiny fraction of them credit their appreciation by citing the papers, they used as reference for their own work.
|Fig. 1 from Grímsson et al. (2020, Lavanttal flora, pt V), Schroeder-type categories based on Köppen signatures (Denk et al. 2013) established for the taxa found in the flora and provided as open data online supplement.|
Short-cited papers and related posts
- Denk T, Grimm GW, Grímsson F, Zetter R. 2013. Evidence from "Köppen signatures" of fossil plant assemblages for effective heat transport of Gulf Stream to subarctic North Atlantic during Miocene cooling. Biogeosciences 10:7927–7942 — open access.
- Grímsson F, Kapli P, Hofmann C-C, Zetter R, Grimm GW. 2017. Eocene Loranthaceae pollen pushes back divergence ages for major splits in the family. PeerJ 5:e3373 [e-pub] — open access — related posts:
- Using consensus networks to understand poor roots
- Trivial but illogical – reconstructing the biogeographic history of the Loranthaceae (again)
- Li R-Q, Chen Z-D, Lu A-M, Soltis DE, Soltis PS, Manos PS. 2004. Phylogenetic relationships in Fagales based on DNA sequences from three genomes. International Journal of Plant Sciences 165:311-324
- Wilf P, Nixon KC, Gandolfo MA, Cúneo NR. 2019. Eocene Fagaceae from Patagonia and Gondwanan legacy in Asian rainforests. Science 364:eaaw5139. — related posts:
- Ockham's Razor applied but not used: can we do DNA-scaffolding with seven characters
- Why we may want to map trait evolution on networks, pt 1 – Introduction
- ... pt 2 – Topological ambiguity
- Surviving parsimonists: just tree-naive or tree-blindfolded?
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