The BBC gets evolution wrong again when describing a new discovery of early eutherian mammals

Well, after uncritically publishing a piece on the new “species” of orangutan (and not even seeking out any dissenting voices, unlike the BBC’s Discover Wildlife site), the BBC news site once again engages in a misleading piece of science reporting. The misguided piece has the headline below (click on screenshot to go there); I’ll get to the text in a minute:

But first, the finding, documented in a paper by Steven Sweetman et al. in Acta Palaeontologica Polonica (reference and free download below). What they found, in a fossil bed in Dorset, were two tiny teeth and several teeth fragments.  From the nature of these “tribosphenic” (three-cusped) teeth, they concluded that what they had was fossil material of a eutherian (placental) mammal from 145 million years ago: the earliest placental known after the therian ancestor (early mammal) split into the eutherians and metatherians (marsupials). In other words, this was on the placental side of the split between all placental mammals and marsupials, a split that took place about 160 million years ago. And it lived only about 15 million years after that split. That’s a very early eutherian mammal.

Can they conclude this from the teeth alone? I suspect so; paleontologists have a long history of studying teeth, and the authors are confident that these three-cusped teeth, which they identified as belonging to two species, are truly placentals rather than marsupials. Read the paper if you want to know more, but be aware that it’s full of paleontological jargon. At any rate, here are the teeth, which, as you can see, are only about 4 mm long (about a sixth of an inch).

Fig. 4. Stereo scanning electron micrographs of studied eutherian mammal specimens from the Ber riasian Purbeck Group of Dorset, southern England; in occlusal view. A. Durlstotherium newmani gen. et sp. nov., NHMUK PV M 99991. B. Durlstodon ensomi gen. et sp. nov., NHMUK PV M 99992.

Here’s a reconstruction of the two species in the paper, showing one of them being eaten by a theropod dinosaur:

(from paper): Fig. 7. Artist’s impression of the Purbeck lagoon at dusk with Durlstodon gen. nov. (left foreground), Durlstotherium gen. nov. (right and center foreground)and the theropod Nuthetes holding a captured Durlstotherium (centre middle distance). Artwork by Mark Witton.

These were clearly small shrewlike mammals, and probably nocturnal insectivores, something that we’ve long thought to be what the placental ancestor was like (see Dawkins’s The Ancestor’s Tale). A recent paper in Nature Ecology & Evolution by Roi Maor et al. (free download, reference and pdf link below) reconstructed the ancestral behavior of the first mammals by going back from the habits of extant mammals, and concluded that the chances were very high that the first mammals were nocturnal. That comports with an old hypothesis, which may well be true, that the earliest mammals were few, and were nocturnal because they were forced to hide from the many existing predatory reptiles. Only when the asteroid destroyed many reptiles, so the story goes, could mammals radiate into the many niches they occupy today, including those earlier filled by reptiles. This story might be what happened, for the radiation of mammals seemed to occur a while after the “ruling reptiles” had largely vanished.

This is all well and good. What is not well and good is the BBC’s characterization of this discovery. Here’s what they said (my emphasis):

Scientists who identified the specimens say they are the earliest undisputed fossils of mammals belonging to the line that led to humans.

They date back 145 million years.

Fossils of the oldest-known ancestors of most living mammals, including human beings, have been unearthed in southern England.

Teeth belonging to the extinct shrew-like creatures, which scampered at the feet of dinosaurs, were discovered in cliffs on the Dorset coast.

Scientists who identified the specimens say they are the earliest undisputed fossils of mammals belonging to the line that led to humans.

They date back 145 million years.

”Here we have discovered from the Jurassic coast a couple of shrew-like things that are to date unequivocally our earliest ancestors,” said Dr Steve Sweetman of Portsmouth University, who examined the ancient teeth.

We know with reasonable certainty that this was an early eutheran mammal. What we do NOT know, and what the BBC says is the case, is that these animals “belonged to the line that led to humans” and, worse, “are our earliest ancestors.” That last mischaracterization is even more dire given that it was pronounced by one of the paper’s authors.

If either of these species are our earliest ancestors, it must have been the species that produced all extant eutherian mammals, including us. We don’t know that: all we know is that it was on the eutherian side of the eutherian/metatherian split, and lived soon after that split occurred. Further, we don’t even know if it was OUR ANCESTOR, for it could have been part of a radiation of these small creatures that went extinct without leaving descendants. In fact, given the frequency of extinction (99% or more of fossils represent species that died out without leaving descendants), that’s the likeliest result. It may be our relative, but not our ancestor.

It’s like saying that, if the diagram below represents the phylogeny of hominins, that Aredepitchecus ramidus or Sahelanthropus tchadensis was “our earliest ancestor”, or “one of the oldest-known ancestors of living humans”. The shrews, like the many hominin species in the diagram below that went extinct, were neither our ancestors nor “unequivocally our earliest ancestors”.  The two hominin species just named were certainly our relatives, and on the hominin side of the hominin/chimp split, but they weren’t on the lineage leading to modern humans, nor were they our ancestors.

It irks me when a respected site like the BBC gets this kind of science reporting wrong. Because the writer doesn’t understand evolution, or wanted to make the findings more “gee-whizzy”, she wrote a misleading article.  Pity.

UPDATE: I added this comment underneath the BBC’s report:

 

Addendum by Greg Mayer

Jerry and I have been discussing this this morning, and he invited me to add my two cents here.  As Jerry correctly points out, it is in general difficult or impossible to say that a particular fossil is an ancestor, as opposed to being a member of the group that includes an ancestor (the latter sometimes phrased as “near” the ancestor), since the chance of that fossil being exactly in the ancestral line (as opposed to near it) is slim.

But it’s also objectionable to call something the “earliest ancestor” without qualification (as the article, and even more regrettably, at least one of the the scientists involved, do), even if you think it is in the exact ancestral line. And that’s because the earliest ancestor goes back to the beginning of life: the “earliest ancestor” of every life form on earth is a billions-of-years-old urprokaryote, and it is the same ancestor for all of life (unless life arose more than once). We also have, of course, have myllokunmingiid, fish, reptilian, etc.  ancestors that come between our bacterial and earliest mammalian ancestors. So, we must specify the taxon, to which we belong, of which the fossil in question is supposed to be the earliest known member. What they should have said is that the new fossils are the earliest known members of the group from which all later eutherian mammals (including Homo) are descended, or for brevity, the “earliest known eutherian”. (Reader Andrew Norman got this right in the comments here earlier this morning.)

This case reminds me of a similar, and erroneous, claim in the press about Protungulatum (although the BBC did better that time), and of the Darwinius scandal.

h/t: H. Stiles

________

 Sweetman, S. C. Grant Smith, and David M. Martill. 2017. Highly derived eutherian mammals from the earliest Cretaceous of southern BritainActa Palaeontologica Polonica in press, available online 07 Nov 2017 doi:https://doi.org/10.4202/app.00408.2017

Maor, R., T. Dayan, H. Ferguson-Gow, and K. E. Jones. 2017. Temporal niche expansion in mammals from a nocturnal ancestor after dinosaur extinction. Nature Ecology & Evolutiondoi:10.1038/s41559-017-0366-5

30 Comments

  1. ThyroidPlanet
    Posted November 7, 2017 at 9:39 am | Permalink

    At first I thought this was more about orangutangate

  2. BJq=
    Posted November 7, 2017 at 9:42 am | Permalink

    Question for all (and Jerry in particular): do outlets like the BBC get these things wrong so often because the authors have agendas, or because these outlets don’t bother/care to hire scientifically literate journalists to run the portions of their organizations dedicated to science?

    • mikeyc
      Posted November 7, 2017 at 9:55 am | Permalink

      Could be simple ambiguity or being imprecise in language. We scientist like to be precise in the way we describe scientific work – it kind of goes with the territory. But to a non-scientist imprecision isn’t that big a deal. So when a scientist says; “this creature is one of our earliest ancestors” they mean it in a direct sense – they mean there is evidence to suggest the creature is an actual ancestor. When a non-scientist says the same thing they are often much fuzzier meaning something like it’s on the family tree and its early so it’s an ancestor. One would hope the BBC would hire someone with a scientist’s perspective to write these , just so as to avoid these issues.

      Imprecision, no agendas. IMO

      • BJ
        Posted November 7, 2017 at 11:46 am | Permalink

        In this particular case, it’s easy to go with your explanation. But every day we see reporting on “science” (often it’s not even science, just some BS pop psychology/sociology from a non-peer reviewed crap “study”) that gets things so wrong and is so obviously sensationalized/biased/completely misunderstand the story that your explanation can’t account for it.

    • DiscoveredJoys
      Posted November 7, 2017 at 10:12 am | Permalink

      My suspicion is that newspapers and broadcasters employ humanities trained people who write attractively but don’t fully understand what they are writing about – because they are cheaper to hire or buy freelance articles from.

      People trained in the sciences and who can write attractively are rather rarer and more expensive. They may be less willing to stick to the organisation’s view of the world too.

      • Posted November 7, 2017 at 12:35 pm | Permalink

        However, one of the wonky statements was made by an author of the paper, not by the BBC’s writer!

    • Curt Nelson
      Posted November 7, 2017 at 10:54 am | Permalink

      My take on this kind of erroneous reporting is that it’s done to make the stories sensational, to attract more readers.

    • Posted November 7, 2017 at 1:41 pm | Permalink

      Most likely a story was written after an interview with the principle scientists, or at least with someone with similar credentials who is familiar with the work. That journalist may have published accurately.
      Then, another journalist takes that story and converts into a story that would be clickbait and/or sell newspapers.

    • Craw
      Posted November 7, 2017 at 5:20 pm | Permalink

      Both. Agendas drive confirmation bias. So if you don’t know much, and reporters don’t know much, it’s easy and comfortable to succumb to confirmation bias.

  3. DrBrydon
    Posted November 7, 2017 at 10:26 am | Permalink

    Well, perhaps that dabster meant it was the ancestor of all people from Dorset, beens it was found there? Still it’s ramshacklum. [Sarcasm with Dorsetshire dialect.]

  4. Andrew David
    Posted November 7, 2017 at 10:33 am | Permalink

    Even if this fossil was of a species that was definitely our ancestor, wouldn’t it be necessary to qualify it as “our earliest known, eutherian ancestor?”

    Or are “known” and “eutherian” taken as granted in this context?

    Or am I missing some other (perhaps obvious) explanation?

  5. Posted November 7, 2017 at 10:34 am | Permalink

    My guess is that the media’s imprecision comes from non-scientists parsing scientists’ sentences and failing to pick up on important distinctions. I doubt their tolerance for imprecision is higher, though perhaps it is for some reporters and some media outlets. The best we can do is write posts like this so they feel some heat when they get it wrong.

  6. GBJames
    Posted November 7, 2017 at 10:38 am | Permalink

    sub

  7. Posted November 7, 2017 at 10:38 am | Permalink

    The BBC was supposed to be improving its science journalism after discussions with the Royal Society. I see no evidence that has happened. They still, like most of the British media, just quote hyped press releases from journal publishers, authors, university or other institutional publicity mongers and the like.

  8. Posted November 7, 2017 at 10:40 am | Permalink

    Darren Naish (excellent scientist & communicator) –
    How Many White Rhino Species Are There? The Conversation Continues
    Is there one white rhino species, or two? And what, if anything, can we do about these intractable debates on lumping versus splitting?
    https://blogs.scientificamerican.com/tetrapod-zoology/how-many-white-rhino-species-are-there-the-conversation-continues/

  9. Posted November 7, 2017 at 10:56 am | Permalink

    If it isn’t the line that led to humans, it can’t be newsworthy. After all, we are the whole reason for the universe to exist.

  10. lkr
    Posted November 7, 2017 at 11:04 am | Permalink

    Good catch, and yes, it’s annoying that everything is interesting only to the extent it’s a “direct ancestor of we-all.

    BTW, scond-last paragraph: should be Ardipithecus afarensis [spelling].

  11. Posted November 7, 2017 at 11:37 am | Permalink

    Ha! I read the headline and thought “do they mean “the earliest organism that was the ancestor of humans but not chimps” or do they mean “the earliest single celled blob that could reproduce”. Turns out, I was wrong, it was “earliest placental mammal”. However, it could also have been earliest tetrapod,, earliest primate, earliest mammal, earliest fish, etc etc etc.

    The BBC (and others) have done this several times for different animal groups to which we belong, always without acknowledging that we don’t know if the fossil is an ancestor or not nor if it is the earliest organism of the specific type in question.

  12. Posted November 7, 2017 at 1:07 pm | Permalink

    It’s all about ratings and we pedantic scientists are just a load of party-poopers and wet blankets.

  13. Clemens
    Posted November 7, 2017 at 1:36 pm | Permalink

    Many thanks Jerry Coyne for this explanation.

    Unfortunately it seems that not only the BBC was imprecisely. A lot of other news sites has used a very similar (fully misleading) headline. For example here is a German site regarding that discovery: http://www.n-tv.de/wissen/Wohl-aelteste-Vorfahren-des-Menschen-entdeckt-article20120926.html

    Because I could not believe that these tooth were really from a 145 million year old primate, I start a search on google. This page has been listed under the first results. – so I get the correct information. 😉 Many thanks & kind regards from the alps of Central Europe

  14. Robert Bakker
    Posted November 7, 2017 at 3:29 pm | Permalink

    The blurb can’t get the correct date: It’s not from the “Jurassic Coast”. As the authors clearly state, the wee chompers come from the Purbeck Mammal Beds, famous for the last century and a half. Early Cretaceous, not Jurassic. Very, very early Cretaceous. Perhaps a bit later than our Breakfast Bench mammals from Wyoming. The Purbeck sample is, indeed, important because the Jurassic/Cretaceous transition seems to record a major faunal disruption. New turtles, new giant ‘dactyls, new families of mammals, now including a hint of an ur-placental — a very exciting addition.

    • Michael Fisher
      Posted November 7, 2017 at 5:08 pm | Permalink

      @ Robert Bakker

      Thanks for the extra, correct info! What is your opinion of the artists impression up top with respect to the background sauropods? Do we think they walked around in lagoon water that’s clearly 3-4 metres deep [assuming adult sauropods in the pic]

  15. ploubere
    Posted November 7, 2017 at 3:43 pm | Permalink

    Given that the statement in question was made by one of the authors, it’s not reasonable to blame the reporter entirely, who presumably was simply writing what that author said.

    What should have happened is that the reporter had enough science background to see a problem with the statement and then asked for clarification. But if the author stuck by the statement, it’s not the reporter’s job to correct it, but to report what was stated by the expert.

  16. ashdeville
    Posted November 7, 2017 at 4:21 pm | Permalink

    Hi Jerry – best wishes from Dorset! I’d swear my cat brought one of them things in this morning!

  17. Craw
    Posted November 7, 2017 at 5:17 pm | Permalink

    I just want to mention once again, Murray Gell-Mann Amnesia Effect.

  18. gravelinspector-Aidan
    Posted November 9, 2017 at 6:19 am | Permalink

    I’ve got to go out and do stuff just now (pulling shoes on), but I’ll read this more carefully when I get back.

    from the Ber riasian Purbeck Group of Dorset,

    That should be “Berriasian” ; a time period in the Early or Middle Cretaceous. Lots of activity in the opening of the Indian Ocean and re-shuffling of Madagascar in that period, not that that has anything to do with Dorset.

  19. Bharathi
    Posted November 16, 2017 at 9:16 pm | Permalink

    Could you comment on this article which draws from that report among other sources?
    https://knappily.com/Environment/meet-some-of-the-oldest-known-mammal-ancestors/5a041bdfc7415d671d12ff0b


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