evolutionnewsandviews--2020-09-15--Kimberella — Traces and a Trace-maker

Kimberella — Traces and a Trace-maker

Editor ’ s note : We are delighted to present a series of posts by paleontologist Günter Bechly on the Ediacaran organism Kimberella .
If identified as an animal , it would “ predate the Cambrian explosion of bilaterian animal phyla as a kind of ‘ advance guard.
’ ” The question is of interest for debates about evolution and arguments about intelligent design raised by Stephen Meyer , among others .
Find the full series about Kimberella here .
The association of Kimberella and its traces was assumed but not proven until the discovery of a lot of fossils @ @ @ @ @ @ @ putative trace-maker Kimberella caught in the act .
The body fossils are generally positioned at the focal points of the fan-shaped scratch marks ( Ivantsov 2013 , Gehling et al .
2014 ) , where “ one end of such a trail is in contact with the head side of the soft body imprint , as if continuing or ‘ flowing ’ from the body ” ( Ivantsov 2010b , 2012 ) .
The first such specimen was an illegally collected fossil from the White Sea area revealed by Mikhail Fedonkin at the @ @ @ @ @ @ @ Italy ) .
It was later returned to Russia by the museum ’ s director Giorgio Teruzzi ( Fedonkin 2001 , Fedonkin & Vickers-Rich 2007 , Ivantsov 2010b , 2012 , 2013 ) , who became the name patron for the new trace fossil species described by Ivantsov ( 2013 ) .
Numerous images of an association of Kimberella fossils with Kimberichnus traces have been provided in the published literature , i.e.
, by Gehling ( 1996 : fig .
5.13 ) , Seilacher ( 1999 : fig .
5 ) , Fedonkin @ @ @ @ @ @ @ , Fedonkin et al .
( 2007b : fig .
20 ) , Trusler et al .
( 2007 : figs 3-4 ) , Peterson et al .
( 2008 : fig .
2a ) , Seilacher & Hagadorn ( 2010 : fig .
1 ) , Ivantsov ( 2009 , 2010b : pl .
1 fig .
6 , 2012 : fig .
12 2013 ) , Gehling et al .
( 2014 : figs 5-7 ) , Scheltema ( 2014 : fig .
1B ) , Vinther ( 2015 : fig @ @ @ @ @ @ @ , Parkhaev ( 2017 : fig .
2b ) , and Giribet & Edgecombe ( 2020 : fig .
46.6B ) .
All these specimens leave hardly any doubt that Kimberella indeed was the maker of the Kimberichnus traces .
Several authors ( Buatois et al .
2014 , Gehling et al .
2014 , Tarhan et al .
2015 ) have convincingly argued that the taxonomic association of the traces , as well as their association with sand pellets ( see below ) , also excludes the fringe hypothesis by Retallack ( @ @ @ @ @ @ @ Ediacaran sediments are of terrestrial origin and that the fan-shaped arrays are “ too straight and sharp to be molluscan radular scratches ” and rather represent “ casts of needle ice ” crystals .
Nevertheless , this example shows how vastly the views of specialists can differ , even though they are all working with the same empirical data .
Lay people are often unaware how much of paleobiology indeed is relatively uncertain interpretation of poor evidence or sometimes even mere speculation .
In the best case it is an inference to the @ @ @ @ @ @ @ reconstruct an unknown past .
And we all know how fallible such a procedure can be .
Clusters of small round tubercles or pits ( 1.5-5 mm in diameter , occasionally even up to 10 mm ) on or near the scratch marks have been interpreted as either fecal pellets or as globular sand casts ( either or prey or of sediment ) from the feeding activity ( Fedonkin & Waggoner 1997 , Fedonkin et al .
2007b , Ivantsov 2010b , 2012,2013 , Gehling et al .
2014 , Vinther 2015 , @ @ @ @ @ @ @ 2019 ) , because they never occur beyond the Kimberichnus fans .
However , Budd & Jensen ( 2017 ) raised questions concerning the origin of these pellets and asked if they might even be only casts of pyrite crystals .
In my view this is highly unlikely , as it would not explain the strict association with the feeding traces .
Nevertheless , again we find the experts to wildly disagree .
Imagine this level of disagreement among expert witnesses in a courtroom .
What do you think a judge or jury @ @ @ @ @ @ @ are not done yet .
As remarked by Ivantsov ( 2017 ) , “ the study of the morphology of body and trace fossils makes it possible to reconstruct the feeding behavior of this animal in details.
” Here we go : Gehling ( 1996 ) , Gehling et al .
( 1995 , 2005 ) , Seilacher et al .
( 2005 ) , and Seilacher & Hagadorn ( 2010 ) claimed that the traces are clearly scratches rasped by a bilateral symmetric structure of two rows of teeth as in modern @ @ @ @ @ @ @ not move-on while it was browsing , but used a long proboscis that swung out more widely the further it extended away from the stationary body.
” Seilacher & Hagadorn ( 2010 : fig .
2 ) even proposed a detailed hypothetical reconstruction of the feeding apparatus and grazing process .
Seilacher & Hagadorn ( 2010 ) also remarked that “ This stationary feeding is quite different from the continuous grazing modes of modern gastropods and chitons and even those of Paleozoic mollusks.
” Likewise , Droser & Gehling ( 2015 ) cautioned @ @ @ @ @ @ @ for Kimberella … should not overlook some important differences from extant gastropod grazing behaviors.
” Seilacher & Hagadorn ( 2010 ) suggested that the stationary feeding strategy of Kimberella disappeared with the Cambrian explosion and its onset of active benthic macropredators , who would have easily bitten off the long proboscis .
This hypothesis is of course quite questionable , as none of the experts reconstructed Kimberella with such a long elephant-trunk-like proboscis , which is also not seen in any of the numerous fossils .
Mainly based on the 16 specimens at @ @ @ @ @ @ @ Gehling et al .
( 2014 ) provided the most elaborate study of the Kimberella feeding traces and reconstructed the feeding style as similar to the scratching of a mechanical shovel excavator : … each pair of grooves is interpreted as corresponding to a single excavation , produced by a rasping action on the substrate .
Due to a pendulum-like movement of the presumed proboscis , the scratch marks in each arcuate set are radially oriented and ascribed to a single focal point on the concave side of each set .
… The @ @ @ @ @ @ @ back toward the focal point … they fan in a manner that suggests repeated probing by a single organ with a pair of ‘ ‘ teeth ’ ’ … The trace fossil arrays of Kimberichnus teruzzii are interpreted as rasping excavations by benthic organisms feeding on biomats … The K. teruzzii scratch fans appear to have been executed by an extensible organ capable of three components of movement .
Each pair of scratches involved a radially directed scratch stroke , like that in living gastropods .
Arcuate sets of scratches were made by @ @ @ @ @ @ @ arcuate swings began with sets close to the anterior end of the animal .
At the end of each set the head end extended to make the next set , with a wider arc .
The fan was completed when the proboscis reached its limit of distal extension .
Having grazed a pie-shaped area of the biomat , the overlapping of scratch fans shows a variety of behaviors .
From specimens with evidence of Kimberella in place ( Figs .
5–7 ) , the animal appears to have first advanced over its previous @ @ @ @ @ @ @ then retreated , or rotated in place , before grazing a new sector of mat .
… Kimberichnus teruzzii is interpreted as the grazing trace of Kimberella quadrata armed with a proboscis bearing two ‘ ‘ teeth ’ ’ .
… Kimberichnus teruzzii and Kimberella quadrata represent the first record of systematic grazing by an epifaunal metazoan of bilaterian grade in the geological record .
The British mollusk specialist Jakob Vinther suggested that the scratch marks were generated by a more complex feeding apparatus similar to a molluscan radula ( Vinther 2015 ) @ @ @ @ @ @ @ organisms “ only Kimberella seems to have actively pushed sediments during self-powered movement ” ( Gehling et al .
2005 , Fedonkin et al .
2007b , Xiao & Laflamme 2009 ) .
The type and pattern of preservation of the feeding trace fossils suggests that “ Kimberella could possibly scratch the mat through its entire thickness or even tear off pieces from it ” ( Sperling & Vinther 2010 , Ivantsov 2012 , 2013 ) .
Ivantsov said that “ by stretching and contracting its body , Kimberella was able to pull @ @ @ @ @ @ @ in order to scratch the substrate covered by microbial mats on which it , probably , fed ” ( Ivantsov 2017 ) , and that “ the animal is believed to have repeatedly passed over the microbial mat during food gathering ” ( Ivantsov et al .
2019 ) .

Kimberella quadrata, an Edicaran organism, by Masahiro miyasaka / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0).
Editor’s note: We are delighted to present a series of posts by paleontologist Günter Bechly on the Ediacaran organism Kimberella. If identified as an animal, it would “predate the Cambrian explosion of bilaterian animal phyla as a kind of ‘advance guard.’” The question is of interest for debates about evolution and arguments about intelligent design raised by Stephen Meyer, among others. Find the full series about Kimberella here.
The association of Kimberella and its traces was assumed but not proven until the discovery of a lot of fossils that show these traces together with the putative trace-maker Kimberella caught in the act. The body fossils are generally positioned at the focal points of the fan-shaped scratch marks (Ivantsov 2013, Gehling et al. 2014), where “one end of such a trail is in contact with the head side of the soft body imprint, as if continuing or ‘flowing’ from the body” (Ivantsov 2010b, 2012). The first such specimen was an illegally collected fossil from the White Sea area revealed by Mikhail Fedonkin at the Museum of Natural History in Milan (Italy). It was later returned to Russia by the museum’s director Giorgio Teruzzi (Fedonkin 2001, Fedonkin & Vickers-Rich 2007, Ivantsov 2010b, 2012, 2013), who became the name patron for the new trace fossil species described by Ivantsov (2013). Numerous images of an association of Kimberella fossils with Kimberichnus traces have been provided in the published literature, i.e., by Gehling (1996: fig. 5.13), Seilacher (1999: fig. 5), Fedonkin (2003: fig. 16), Fedonkin et al. (2007b: fig. 20), Trusler et al. (2007: figs 3-4), Peterson et al. (2008: fig. 2a), Seilacher & Hagadorn (2010: fig. 1), Ivantsov (2009, 2010b: pl. 1 fig. 6, 2012: fig. 12 2013), Gehling et al. (2014: figs 5-7), Scheltema (2014: fig. 1B), Vinther (2015: fig. 3C,D,F), Parkhaev (2017: fig. 2b), and Giribet & Edgecombe (2020: fig. 46.6B). All these specimens leave hardly any doubt that Kimberella indeed was the maker of the Kimberichnus traces.
Several authors (Buatois et al. 2014, Gehling et al. 2014, Tarhan et al. 2015) have convincingly argued that the taxonomic association of the traces, as well as their association with sand pellets (see below), also excludes the fringe hypothesis by Retallack (2013), who suggested that these Ediacaran sediments are of terrestrial origin and that the fan-shaped arrays are “too straight and sharp to be molluscan radular scratches” and rather represent “casts of needle ice” crystals. Nevertheless, this example shows how vastly the views of specialists can differ, even though they are all working with the same empirical data. Lay people are often unaware how much of paleobiology indeed is relatively uncertain interpretation of poor evidence or sometimes even mere speculation. In the best case it is an inference to the best explanation, using circumstantial evidence to reconstruct an unknown past. And we all know how fallible such a procedure can be.
Pellets
Clusters of small round tubercles or pits (1.5-5 mm in diameter, occasionally even up to 10 mm) on or near the scratch marks have been interpreted as either fecal pellets or as globular sand casts (either or prey or of sediment) from the feeding activity (Fedonkin & Waggoner 1997, Fedonkin et al. 2007b, Ivantsov 2010b, 2012,2013, Gehling et al. 2014, Vinther 2015, Coutts et al. 2016, Coutts 2019), because they never occur beyond the Kimberichnus fans. However, Budd & Jensen (2017) raised questions concerning the origin of these pellets and asked if they might even be only casts of pyrite crystals. In my view this is highly unlikely, as it would not explain the strict association with the feeding traces. Nevertheless, again we find the experts to wildly disagree. Imagine this level of disagreement among expert witnesses in a courtroom. What do you think a judge or jury would have to conclude? But we are not done yet.
Reconstructing the Feeding Mode
As remarked by Ivantsov (2017), “the study of the morphology of body and trace fossils makes it possible to reconstruct the feeding behavior of this animal in details.” Here we go:
Gehling (1996), Gehling et al. (1995, 2005), Seilacher et al. (2005), and Seilacher & Hagadorn (2010) claimed that the traces are clearly scratches rasped by a bilateral symmetric structure of two rows of teeth as in modern radulas, and that “Kimberella did not move-on while it was browsing, but used a long proboscis that swung out more widely the further it extended away from the stationary body.” Seilacher & Hagadorn (2010: fig. 2) even proposed a detailed hypothetical reconstruction of the feeding apparatus and grazing process.
Seilacher & Hagadorn (2010) also remarked that “This stationary feeding is quite different from the continuous grazing modes of modern gastropods and chitons and even those of Paleozoic mollusks.” Likewise, Droser & Gehling (2015) cautioned that “the suggestions of molluscan affinities for Kimberella … should not overlook some important differences from extant gastropod grazing behaviors.”
Seilacher & Hagadorn (2010) suggested that the stationary feeding strategy of Kimberella disappeared with the Cambrian explosion and its onset of active benthic macropredators, who would have easily bitten off the long proboscis. This hypothesis is of course quite questionable, as none of the experts reconstructed Kimberella with such a long elephant-trunk-like proboscis, which is also not seen in any of the numerous fossils.
Like a Mechanical Shovel Excavator?
Mainly based on the 16 specimens at the South Australian Museum in Adelaide, Gehling et al. (2014) provided the most elaborate study of the Kimberella feeding traces and reconstructed the feeding style as similar to the scratching of a mechanical shovel excavator:
… each pair of grooves is interpreted as corresponding to a single excavation, produced by a rasping action on the substrate. Due to a pendulum-like movement of the presumed proboscis, the scratch marks in each arcuate set are radially oriented and ascribed to a single focal point on the concave side of each set. … The rasping motion appears to have been directed back toward the focal point … they fan in a manner that suggests repeated probing by a single organ with a pair of ‘‘teeth’’ … The trace fossil arrays of Kimberichnus teruzzii are interpreted as rasping excavations by benthic organisms feeding on biomats … The K. teruzzii scratch fans appear to have been executed by an extensible organ capable of three components of movement. Each pair of scratches involved a radially directed scratch stroke, like that in living gastropods. Arcuate sets of scratches were made by stepwise lateral shifts between strokes. The arcuate swings began with sets close to the anterior end of the animal. At the end of each set the head end extended to make the next set, with a wider arc. The fan was completed when the proboscis reached its limit of distal extension. Having grazed a pie-shaped area of the biomat, the overlapping of scratch fans shows a variety of behaviors. From specimens with evidence of Kimberella in place (Figs. 5–7), the animal appears to have first advanced over its previous excavations to a new stationary locus and then retreated, or rotated in place, before grazing a new sector of mat. … Kimberichnus teruzzii is interpreted as the grazing trace of Kimberella quadrata armed with a proboscis bearing two ‘‘teeth’’. … Kimberichnus teruzzii and Kimberella quadrata represent the first record of systematic grazing by an epifaunal metazoan of bilaterian grade in the geological record.
The British mollusk specialist Jakob Vinther suggested that the scratch marks were generated by a more complex feeding apparatus similar to a molluscan radula (Vinther 2015). He said that
specimens are found in great abundance on surfaces that also preserve distinct scraping traces named Kimberichnus Ivantsov, 2013 (Fig. 3B), which is also well known from Australia (Gehling et al. 2014). These traces suggest a mode of feeding on the microbial mats involving two larger teeth (forming paired grooves), and a series of smaller denticles (as evidenced by the presence of relief outside the tooth marks indicating feeding over a larger area by a more elaborate feeding apparatus than the visible paired teeth marks; Fig. 3B).
Among all Ediacaran organisms “only Kimberella seems to have actively pushed sediments during self-powered movement” (Gehling et al. 2005, Fedonkin et al. 2007b, Xiao & Laflamme 2009). The type and pattern of preservation of the feeding trace fossils suggests that “Kimberella could possibly scratch the mat through its entire thickness or even tear off pieces from it” (Sperling & Vinther 2010, Ivantsov 2012, 2013). Ivantsov said that “by stretching and contracting its body, Kimberella was able to pull and push its head part bearing teeth in order to scratch the substrate covered by microbial mats on which it, probably, fed” (Ivantsov 2017), and that “the animal is believed to have repeatedly passed over the microbial mat during food gathering” (Ivantsov et al. 2019).
Next, “Kimberella — Locomotory Tracks.”


evolutionnewsandviews--2020-09-15--Doctor’s Diary: No “Butts” About It

Doctor’s Diary: No “Butts” About It

Editor ’ s note : Dr. Simmons is a physician and the author most recently of Are We Here to Re-Create Ourselves ?
He is a Fellow with Discovery Institute ’ s Center for Science & Culture .
“ How did human butts evolve to look that way ?
” So asks Darcy Shapiro , a PhD in evolutionary anthropology from Rutgers University , writing at the site Massive Science .
Shapiro ’ s article is intriguing , entertaining , yet falls short .
She writes that the evolution of bipedal-walking primates was primarily caused by the shifting of select @ @ @ @ @ @ @ Why these bones shifted and changed shape is not clearly stated .
But that is just the question .
And it ’ s made more interesting by the fact that fossils do not document the gradual evolution of the human pelvis .
Instead its appearance seems to have been “ very rapid.
” Whatever the case , the process resulted in the larger , more desirable human buttocks ( I mean , desirable in a strictly scientific sense , of course ) .
Consider the striking and symmetric increase in adipose tissue in @ @ @ @ @ @ @ us .
Apes barely have this .
Their butts are mostly flat .
Other differences include the following : many primate butts ( not ours ) can change at mating time to a violet red color and swell to several times their normal size .
I ’ ve not seen this phenomenon in humans , not during my four years in medical school , my rotations during specialty training which included OB , nor during my more than 44 years of practice .
Some primates can also get markedly enlarged perianal glands , @ @ @ @ @ @ @ buttocks , I ’ m sorry to say , a rather unappealing appearance .
Fortunately , we didn ’ t inherit that trait , either .
Shapiro comments that our large brains and the use of language with symbols are distinguishing human features , but not nearly as distinguishing as our butt .
Honestly ?
Seriously ?
Perhaps that is tongue in cheek , but one can ’ t be sure .
I agree all butts are important , and , as I age , maybe sitting down has become more important to @ @ @ @ @ @ @ to think that our intelligence remains the most important quality .
The author offers a nice , smooth story , but one that is fitted to selected facts .
It ’ s so smooth that you can easily envision a documentary film showing primates achieving increasingly erect bipedal walking as butts change into their present shape .
Perhaps evolution occurred to permit reaching higher and higher hanging fruit , doing pull-ups on chinning bars , or eventually playing basketball .
We do know that basketball players were under six feet tall a hundred @ @ @ @ @ @ @ over seven feet .
Proof of evolution ?
Another change involves the shape and size of the gluteus maximus , the major muscle in our backside .
There are two of them .
They are the ones we sit on .
Was foresight at work ?
One aimed at our eventually fitting into lounge chairs and car seats ?
Maybe we lost our tails for the same reason .
We also lost prehensile toes , which makes hanging in trees more treacherous .
These days I wouldn ’ t even consider it .
@ @ @ @ @ @ @ do not have butts that are proportionally as big as humans .
Indeed , that seems true , but I ’ m not aware of research where someone has actually gone out and measured butts on a variety of primates .
Or sought a comparative , random cross-section of human butts measured when the subjects least expect it .
Maybe researcher safety was an issue .
We have a lot of fossilized pelvic bones from the past , but no soft tissues to compare .
Perhaps the famed Lucy had a wonderfully shaped @ @ @ @ @ @ @ .
One might ask why primate arms shortened while the legs lengthened .
Perhaps , knuckle walking resulted in too many splinters or the powers of natural selection knew there would be an upcoming need to do desk work .
According to research from the University of Leiden , chimps recognize each other by their butts .
We are inclined to use faces .
Good thing , I think .
But why did the pelvis really need to change shape at all ?
Monkeys and apes can walk upright , albeit in a @ @ @ @ @ @ @ do with birthing .
Pelvic outlets , where the baby ’ s head comes out first , are strikingly different between the great apes and humans .
Might it be that human babies are often double the size of gorilla babies ( 5-10 pounds compared to 3-4 pounds ) and evolution knew this would eventually be a problem ?
Of note , our babies have to look sideways to get through and then look downward .
In seriousness , Shapiro commits a classic error : she identifies a set of features needed for @ @ @ @ @ @ @ evidence for evolution , constructing a just-so story to account for its origin when that could be equally well explained by intelligent design .
After all , designers use foresight and goal-oriented thinking to piece together multiple features and components that work in coordination to perform a function .
As Shapiro explains , this coordination is exactly what we see in the carefully crafted shape of the bones , muscles , and fat tissue of our butts to allow us to efficiently walk upright , and also to do something that evolution could @ @ @ @ @ @ @ periods of time and do intelligent work at our desks .
This coordination is not evidence of blind and unguided evolution but rather of purposeful action by an intelligent agent .
Design is implied , no “ butts ” about it .

The Three Graces, by Raphael / Public domain.
Editor’s note: Dr. Simmons is a physician and the author most recently of Are We Here to Re-Create Ourselves? He is a Fellow with Discovery Institute’s Center for Science & Culture.
“How did human butts evolve to look that way?” So asks Darcy Shapiro, a PhD in evolutionary anthropology from Rutgers University, writing at the site Massive Science.
Shapiro’s article is intriguing, entertaining, yet falls short. She writes that the evolution of bipedal-walking primates was primarily caused by the shifting of select bones and muscles in the pelvis. Why these bones shifted and changed shape is not clearly stated. But that is just the question. And it’s made more interesting by the fact that fossils do not document the gradual evolution of the human pelvis. Instead its appearance seems to have been “very rapid.” Whatever the case, the process resulted in the larger, more desirable human buttocks (I mean, desirable in a strictly scientific sense, of course).
Humans and Apes
Consider the striking and symmetric increase in adipose tissue in each cheek, which is unique to us. Apes barely have this. Their butts are mostly flat. Other differences include the following: many primate butts (not ours) can change at mating time to a violet red color and swell to several times their normal size. I’ve not seen this phenomenon in humans, not during my four years in medical school, my rotations during specialty training which included OB, nor during my more than 44 years of practice. Some primates can also get markedly enlarged perianal glands, bulging from the rectum and giving the buttocks, I’m sorry to say, a rather unappealing appearance. Fortunately, we didn’t inherit that trait, either.
Shapiro comments that our large brains and the use of language with symbols are distinguishing human features, but not nearly as distinguishing as our butt. Honestly? Seriously? Perhaps that is tongue in cheek, but one can’t be sure. I agree all butts are important, and, as I age, maybe sitting down has become more important to me, but I’m inclined to think that our intelligence remains the most important quality.
The author offers a nice, smooth story, but one that is fitted to selected facts. It’s so smooth that you can easily envision a documentary film showing primates achieving increasingly erect bipedal walking as butts change into their present shape. Perhaps evolution occurred to permit reaching higher and higher hanging fruit, doing pull-ups on chinning bars, or eventually playing basketball. We do know that basketball players were under six feet tall a hundred years ago and now many are well over seven feet. Proof of evolution?
Another change involves the shape and size of the gluteus maximus, the major muscle in our backside. There are two of them. They are the ones we sit on. Was foresight at work? One aimed at our eventually fitting into lounge chairs and car seats? Maybe we lost our tails for the same reason. We also lost prehensile toes, which makes hanging in trees more treacherous. These days I wouldn’t even consider it.
Perilous Research
Dr. Shapiro states that the great apes do not have butts that are proportionally as big as humans. Indeed, that seems true, but I’m not aware of research where someone has actually gone out and measured butts on a variety of primates. Or sought a comparative, random cross-section of human butts measured when the subjects least expect it. Maybe researcher safety was an issue. We have a lot of fossilized pelvic bones from the past, but no soft tissues to compare. Perhaps the famed Lucy had a wonderfully shaped buttocks. We don’t know. One might ask why primate arms shortened while the legs lengthened. Perhaps, knuckle walking resulted in too many splinters or the powers of natural selection knew there would be an upcoming need to do desk work.
According to research from the University of Leiden, chimps recognize each other by their butts. We are inclined to use faces. Good thing, I think. But why did the pelvis really need to change shape at all? Monkeys and apes can walk upright, albeit in a bowlegged fashion. Perhaps it had to do with birthing. Pelvic outlets, where the baby’s head comes out first, are strikingly different between the great apes and humans. Might it be that human babies are often double the size of gorilla babies (5-10 pounds compared to 3-4 pounds) and evolution knew this would eventually be a problem? Of note, our babies have to look sideways to get through and then look downward.
A Classic Error
In seriousness, Shapiro commits a classic error: she identifies a set of features needed for some function, but conflates that with evidence for evolution, constructing a just-so story to account for its origin when that could be equally well explained by intelligent design.
After all, designers use foresight and goal-oriented thinking to piece together multiple features and components that work in coordination to perform a function. As Shapiro explains, this coordination is exactly what we see in the carefully crafted shape of the bones, muscles, and fat tissue of our butts to allow us to efficiently walk upright, and also to do something that evolution could never have anticipated: sit for long periods of time and do intelligent work at our desks.
This coordination is not evidence of blind and unguided evolution but rather of purposeful action by an intelligent agent. Design is implied, no “butts” about it.


evolutionnewsandviews--2020-09-18--Tour to Meyer: Make Your Best Case for the Theory of Intelligent Design

On a new episode of ID the Future , Rice University chemist James Tour and Discovery Institute philosopher of science @ @ @ @ @ about the origin of life and intelligent design .
They assess an exchange about the @ @ @ @ @ and Jeremy England , and Tour notes his hesitance about ID .
Professor Tour asks @ @ @ @ @ best case for the theory of intelligent design .
Download the podcast or listen to @ @ @ @ @ is excerpted from a longer interview Dr. Tour conducted with Dr. Meyer as part of @ @ @ @ @ , The Science & Faith Podcast : Follow the Evidence .

Photo: James Tour interviewing Stephen Meyer.
On a new episode of ID the Future, Rice University chemist James Tour and Discovery Institute philosopher of science Stephen Meyer continue their conversation about the origin of life and intelligent design. They assess an exchange about the former between physicists Brian Miller and Jeremy England, and Tour notes his hesitance about ID. Professor Tour asks Dr. Meyer to make his best case for the theory of intelligent design. Download the podcast or listen to it here.
The episode is excerpted from a longer interview Dr. Tour conducted with Dr. Meyer as part of his excellent new video series, The Science & Faith Podcast: Follow the Evidence.


evolutionnewsandviews--2020-09-18--Reform It Altogether — More on the Naturalistic Parabola

Editor ’ s note : This is part 2 of a series by Dr. Nelson , “ Trapped in the Naturalistic Parabola.
” On Saturday , September 12 , I presented a webinar about design triangulation , a method of functional analysis in biology ( or in complex systems generally ) with great promise for helping intelligent design , as a scientific enterprise , to climb free of what I ’ ve called the hopeless grip of the “ naturalistic parabola.
” The pdf of that webinar is available here .
Some background .
Recently , a doctoral student whom @ @ @ @ @ @ @ and then at the Discovery Institute Summer Seminar , told me that she had read a large unpublished manuscript with the transcripts of an ID research meeting , held at Calvin College nearly twenty years ago .
I was present at that meeting , along with Steve Meyer , Bill Dembski , Rob Koons , and other familiar names .
This student told me that my transcribed remarks focused in particular on the need for ID to provide “ something new , something of its own ” to the scientific dialogue .
So @ @ @ @ @ @ @ for a long time .
And Discovery Institute colleagues have occasionally chided me for my obsession .
There is more than one way , they object , to conceive of the empirical content of any scientific theory .
Your single-minded focus , Paul , on novel predictions from ID , unjustifiably privileges that epistemic virtue over equally valuable desiderata , such as explanation or unification .
Get over your novel predictions craving already .
Well , all right .
I learned my Michael Scriven like a good boy , just like every other @ @ @ @ @ @ @ .
But many years of lectures on ID at colleges and universities in the U.S. and overseas have taught me that the naturalistic parabola is all too real .
For example : not long after the Calvin College ID research meeting , I was speaking at Wayne State University in Detroit , about ID and evolutionary theory .
Following the talk , as I was packing up my computer , a young biochemist on the Wayne State faculty , who identified himself as a Christian ( thus , he acknowledged , he was @ @ @ @ @ @ @ maybe ) , approached me at the podium .
You spent a lot of time in your talk criticizing evolutionary theory , he began , and I can agree with much of what you said .
But what can you offer me using design ( he asked ) that I can take back to my lab and apply ?
I have never forgotten his question , or my fumbling reply .
It struck me that , indeed , nearly all of my talk had addressed shortcomings in evolutionary theory .
By implication , @ @ @ @ @ @ @ only I had said almost nothing about it .
Life in the Naturalistic Parabola Ain ’ t Much to Crow About And that is because , since my first days as an undergraduate studying evolutionary biology and the philosophy of science ( 1980-1984 ) , and then into graduate school , I had been living mentally , at least where biological inquiry was concerned , mostly within the naturalistic parabola .
Everybody else in academic biology lived there , so…it seemed natural .
But not , it turns out , if one also @ @ @ @ @ @ @ in science .
Figure 1 shows natural selection as the evolutionary process proposed by Darwin , and held chiefly responsible by neo-Darwinian theory in the 20th century , as the cause of adaptive biological complexity .
I spent literally thousands of study hours probing the logical and evidential structure of the theory of natural selection .
I wanted to learn about the evidence for selection , but also to satisfy myself — in light of the evidence that selection needed , to explain macroevolution , but which did not exist — that the @ @ @ @ @ @ @ not accomplish what Darwin , or Dawkins , or my biology professors ( some of them , anyway ) thought it could .
Having done my due diligence , I could put a red X through selection ( see Figure 2 ) .
What next ?
“ What next , ” however , if one is living within the naturalistic parabola , will be governed by the parabola itself .
Figure 2 shows the route ( blue arrow ) taken by many evolutionary theorists , who themselves were unsatisfied with the neo-Darwinian case @ @ @ @ @ @ @ Michael Lynch , for instance , now at the BioDesign Institute of Arizona State University , wrote in 2007 that “ it is a leap to assume that selection accounts for all evolutionary change , particularly at the molecular and cellular levels .
The blind worship of natural selection is not evolutionary biology .
It is arguably not even science ” ( Lynch 2007 , 369 ) .
Lynch argues that what has come to be known as constructive neutral evolution ( CNE ) is far more significant .
Segue to CNE , @ @ @ @ @ @ @ Ann Gauger , Steve Meyer , and I critiqued constructive neutral evolution in Chapter 8 of the Theistic Evolution volume ( Meyer , Gauger & Nelson 2017 ) .
Once again , I spent long hours plowing through the CNE literature , attending talks by CNE theorists , and discussing CNE , pro and con , at ID research meetings .
Could CNE build the ribosome , the photosynthetic apparatus , or ATP synthase ?
Or any animal body plan ?
Almost certainly not .
Put another red X through a proposed evolutionary @ @ @ @ @ @ @ You Can Do That All Day and Never Make a Lick of Progress Nope .
As the saying goes , after someone sits through a bad movie : you ’ ll never get those hours back .
The blue arrow within the parabola will move on to the next naturalistic proposal ( see Figure 3 ) , and on again , after that , indefinitely into the future .
The failure of CNE , when it comes , will not be the end .
It couldn ’ t be , as along as @ @ @ @ @ @ @ .
Natural selection , when it tumbled for many evolutionary theorists in the last two decades of the 20th century , certainly wasn ’ t the end .
The naturalistic project goes on , my friend : shoulder to the wheel .
The reader should be able to see now , if it wasn ’ t obvious in part 1 of this series , the abject futility of trying to construct a theory of biological design within a philosophical framework , naturalism , fundamentally committed to another goal .
Reform it altogether , @ @ @ @ @ @ @ triangulation is a stumbling step in that direction .
Reform it altogether , and let the naturalistic parabola go on its own way .
Meyer , Stephen , Ann Gauger , & Paul Nelson .
2017 .
Theistic Evolution and the Extended Evolutionary Synthesis : Does It Work ?
In J.P. Moreland et al.
, eds.
, Theistic Evolution : A Scientific , Philosophical , and Theological Critique .
Wheaton , IL : Crossway .

Image credit: Damir Belavić via Pixabay.
Editor’s note: This is part 2 of a series by Dr. Nelson, “Trapped in the Naturalistic Parabola.”
On Saturday, September 12, I presented a webinar about design triangulation, a method of functional analysis in biology (or in complex systems generally) with great promise for helping intelligent design, as a scientific enterprise, to climb free of what I’ve called the hopeless grip of the “naturalistic parabola.” The pdf of that webinar is available here.
Been A Long Time Coming
Some background. Recently, a doctoral student whom I came to know via email, and then at the Discovery Institute Summer Seminar, told me that she had read a large unpublished manuscript with the transcripts of an ID research meeting, held at Calvin College nearly twenty years ago. I was present at that meeting, along with Steve Meyer, Bill Dembski, Rob Koons, and other familiar names. This student told me that my transcribed remarks focused in particular on the need for ID to provide “something new, something of its own” to the scientific dialogue.
So I’ve fussed about this point for a long time. And Discovery Institute colleagues have occasionally chided me for my obsession. There is more than one way, they object, to conceive of the empirical content of any scientific theory. Your single-minded focus, Paul, on novel predictions from ID, unjustifiably privileges that epistemic virtue over equally valuable desiderata, such as explanation or unification. Get over your novel predictions craving already.
Well, all right. I learned my Michael Scriven like a good boy, just like every other philosophy of biology student in the 1980s. But many years of lectures on ID at colleges and universities in the U.S. and overseas have taught me that the naturalistic parabola is all too real. For example: not long after the Calvin College ID research meeting, I was speaking at Wayne State University in Detroit, about ID and evolutionary theory. Following the talk, as I was packing up my computer, a young biochemist on the Wayne State faculty, who identified himself as a Christian (thus, he acknowledged, he was philosophically pre-disposed to find ID worthwhile, maybe), approached me at the podium. You spent a lot of time in your talk criticizing evolutionary theory, he began, and I can agree with much of what you said.
But what can you offer me using design (he asked) that I can take back to my lab and apply?
I have never forgotten his question, or my fumbling reply. It struck me that, indeed, nearly all of my talk had addressed shortcomings in evolutionary theory. By implication, the ID alternative was more promising — only I had said almost nothing about it.
Life in the Naturalistic Parabola Ain’t Much to Crow About
And that is because, since my first days as an undergraduate studying evolutionary biology and the philosophy of science (1980-1984), and then into graduate school, I had been living mentally, at least where biological inquiry was concerned, mostly within the naturalistic parabola. Everybody else in academic biology lived there, so…it seemed natural. But not, it turns out, if one also wants to be an independently creative dissenter in science.
Figure 1.
Figure 1 shows natural selection as the evolutionary process proposed by Darwin, and held chiefly responsible by neo-Darwinian theory in the 20th century, as the cause of adaptive biological complexity. I spent literally thousands of study hours probing the logical and evidential structure of the theory of natural selection. I wanted to learn about the evidence for selection, but also to satisfy myself — in light of the evidence that selection needed, to explain macroevolution, but which did not exist — that the process, while perfectly real, could not accomplish what Darwin, or Dawkins, or my biology professors (some of them, anyway) thought it could. Having done my due diligence, I could put a red X through selection (see Figure 2). What next?
Figure 2.
“What next,” however, if one is living within the naturalistic parabola, will be governed by the parabola itself. Figure 2 shows the route (blue arrow) taken by many evolutionary theorists, who themselves were unsatisfied with the neo-Darwinian case for the centrality of natural selection. Michael Lynch, for instance, now at the BioDesign Institute of Arizona State University, wrote in 2007 that “it is a leap to assume that selection accounts for all evolutionary change, particularly at the molecular and cellular levels. The blind worship of natural selection is not evolutionary biology. It is arguably not even science” (Lynch 2007, 369). Lynch argues that what has come to be known as constructive neutral evolution (CNE) is far more significant.
Segue to CNE, then, to check it out. Ann Gauger, Steve Meyer, and I critiqued constructive neutral evolution in Chapter 8 of the Theistic Evolution volume (Meyer, Gauger & Nelson 2017). Once again, I spent long hours plowing through the CNE literature, attending talks by CNE theorists, and discussing CNE, pro and con, at ID research meetings.
Could CNE build the ribosome, the photosynthetic apparatus, or ATP synthase? Or any animal body plan? Almost certainly not. Put another red X through a proposed evolutionary mechanism. Getting somewhere, finally!
You Can Do That All Day and Never Make a Lick of Progress
Nope. As the saying goes, after someone sits through a bad movie: you’ll never get those hours back. The blue arrow within the parabola will move on to the next naturalistic proposal (see Figure 3), and on again, after that, indefinitely into the future. The failure of CNE, when it comes, will not be the end. It couldn’t be, as long as one is committed to the naturalistic project. Natural selection, when it tumbled for many evolutionary theorists in the last two decades of the 20th century, certainly wasn’t the end. The naturalistic project goes on, my friend: shoulder to the wheel.
Figure 3.
The reader should be able to see now, if it wasn’t obvious in part 1 of this series, the abject futility of trying to construct a theory of biological design within a philosophical framework, naturalism, fundamentally committed to another goal. Reform it altogether, said Hamlet to the players.
Design triangulation is a stumbling step in that direction. Reform it altogether, and let the naturalistic parabola go on its own way.
References
Lynch, Michael. 2007. The Origins of Genome Architecture. Sunderland, MA: Sinauer.
Meyer, Stephen, Ann Gauger, & Paul Nelson. 2017. Theistic Evolution and the Extended Evolutionary Synthesis: Does It Work? In J.P. Moreland et al., eds., Theistic Evolution: A Scientific, Philosophical, and Theological Critique. Wheaton, IL: Crossway.


evolutionnewsandviews--2020-09-18--Kimberella and Controversial Relationships — A Chronological Synopsis

Editor ’ s note : We are delighted to present a series of posts by paleontologist Günter Bechly on the Ediacaran organism Kimberella .
If identified as an animal , it would “ predate the Cambrian explosion of bilaterian animal phyla as a kind of ‘ advance guard.
’ ” The question is of interest for debates about evolution and arguments about intelligent design raised by Stephen Meyer , among others .
Find the full series about Kimberella here .
Glaessner & Daily ( 1959 ) figured a specimen of Kimberella as a “ problematic fossil , possibly belonging to @ @ @ @ @ @ @ 1966 ) compared Kimberella with Leptomedusae , Trachymedusina , and Carybdeida ( Cubozoa or box jellies ) .
They agreed that “ the existence of most of its characters in one or more of these groups indicates its medusoid affinities.
” Their main argument was an assumed homology of the apparent “ segmented zones ” with the gonads in some jellyfish groups .
Wade ( 1972 ) discussed the assumed medusoid affinities , agreed with the interpretation of the segmented zones as medusoid gonads and gastric pouches , and even believed themselves to @ @ @ @ @ @ @ Kimberella is “ probably a Scyphozoan ” ( true jelly ) .
Jenkins ( 1984 , 1992 ) thoroughly reviewed and reevaluated the morphology of Kimberella and came to somewhat different interpretations ( e.g.
, concerning the puckered gonads ) but also concluded that a medusoid affinity is obvious .
He described in detail for Kimberella the presence of medusoid organs like the bell , 2-3 puckered gonads , subumbrella , rhopalia , and pedalia supporting the tentacles .
He suggested that Kimberella is a cubozoan box jelly and even is the direct @ @ @ @ @ @ @ , which are responsible for many severe accidents for swimmers on the Australian coast .
Such a cubomedusoid affinity was also endorsed by Glaessner ( 1984 ) .
It is remarkable , indeed , how detailed a medusoid morphology was projected onto Kimberella fossils and later recognized as pure fantasy .
After the new and better preserved White Sea material was discovered in 1994 and described by Fedonkin & Waggoner ( 1997 ) , Fedonkin ( 1998 ) , and Waggoner ( 1998 ) , these authors totally rejected the previous medusoid interpretation @ @ @ @ @ @ @ organism “ had no tentacles , no tetraradiate symmetry , and no bell.
” They also rejected a possible affinity with the more typical Ediacaran organisms .
Instead they interpreted Kimberella as “ a bilaterian , more complex than a platyhelminth [ flatworm ] , and more like a mollusk than anything else living.
” Nevertheless , Fedonkin & Waggoner offered the qualification , “ We can not prove a molluscan affinity conclusively ; some definitive molluscan synapomorphies , like the radula , can not be seen , and others are open to @ @ @ @ @ @ @ 1999 ) thought that the trace fossils “ record a bilateral radula and its usage in pendulum grazing , which is definitely a molluscan feature … as is the impression of a broad muscular foot.
” Seilacher ( 1999 ) speculated that “ the Kimberella animal could have been a halkieriid , ” which is a mollusk-like Cambrian organism .
Independent of its affiliation , however , he thought that it could be properly modeled after modern “ soft limpets.
” Erwin ( 1999 ) was very skeptical of previous attributions of Ediacaran @ @ @ @ @ @ @ “ those who would assign Ediacaran fossils to protostomes and deuterostomes have generally failed to identify any diagnostic characters which unambiguously support such assignments .
At present then , claims of a higher metazoan affinity must be regarded as unproven.
” Nevertheless , he characterized Kimberella as “ triploblastic , benthic organism with a broad , well-muscled foot and a broad visceral cavity .
Such an organism would have required at least a hemaeocoel .
No appendages are present ( as is true of all Ediacaran forms ) nor is a mouth apparent.
@ @ @ @ @ @ @ is not clearly a mollusc ( Fedonkin and Waggoner ’ s preferred interpretation ) or even a protostome , it is more complex than a cnidarian ” and “ Kimberella could also represent a stem-group bilaterian ” before the protostome-deuterostome ancestor .
Budd & Jensen ( 2000 ) commented as follows : “ Perhaps the strongest case for an Ediacaran bilaterian body fossil has been made by Fedonkin & Wagonner [ sic ] ( 1997 ) for Kimberella , which they describe as mollusk-like .
It is a relatively large , bilaterally symmetrical @ @ @ @ @ @ @ both a dorsal shell and a ‘ foot ’ .
Nevertheless , Kimberella does not possess any unequivocal derived molluscan features , and its assignment to the Mollusca or even the Bilateria must be considered to be unproven ( cf .
Erwin , 1999 ) .
” Martin et al .
( 2000 ) called Kimberella the “ oldest well-documented triploblastic bilaterian , ” but still admitted that “ whether Kimberella at 555 Ma indicates that the protostome-deuterostome split is even older is not yet resolvable.
” Erwin & Davidson ( 2002 ) @ @ @ @ @ @ @ accepted bilaterian fossil ” and “ oldest convincing remains of bilaterians are fossils of an already well-developed animal ” and “ demonstrable adult bilaterian form.
” Furthermore , they said that Kimberella “ is interpreted as a benthic animal , most likely of protostome affinity , and possibly a mollusk.
” Dzik ( 2003 ) did not consider the Kimberella fossils as ventral casts but rather as “ external molds of the collapsed upper surface of the body.
” Therefore , he claimed that the similarity to limpet soles is quite superficial and @ @ @ @ @ @ @ .
He also said that “ the main argument for the molluscan nature of Kimberella remains thus its association with putative radular marks proposed by Seilacher ( 1999 ) .
However , it is unclear what these structures truly represent.
” Instead , Dzik thought that the stable width between supposed gut and the body surface was filled with a kind of mesoglea and mesogleal muscles , which “ would point to ctenophoran affinities of Kimberella.
” He therefore interpreted Kimberella as a freely swimming animal and possible comb jelly .
Fedonkin ( @ @ @ @ @ @ @ new interpretation of Kimberella as a mollusk-like triploblastic animal.
” Seilacher et al .
( 2003 , 2005 ) called Kimberella a “ soft limpet ” and “ primitive mollusk , ” and said that “ the molluscan nature of Kimberella is expressed by impressions of the flat foot and the margin of a soft dorsal shield seen in ventral deathmasks of the bodies , ” which he obviously considered as putative synapomorphies .
Valentine ( 2004 ) listed Kimberella as “ a possible eutrochozoan ” and “ a mollusc-like bilaterian organism.
” @ @ @ @ @ @ @ “ although Kimberella is interpreted as having a cap-shaped shell , there is evidence only of a relatively rigid dorsal region , and assignment to Mollusca is based on general similarity of form.
” Mainly based on Fedonkin & Waggoner ( 1997 ) , Caron et al .
( 2006 ) considered Kimberella as an earliest stem group mollusk , succeeded by the Lower Cambrian stem group mollusks Odontogriphus , Wiwaxia , and Halkieria .
These authors especially mentioned the following commonalities between Kimberella and the soft-bodied organism Odontogriphus : dorso-ventrally flattened ovoid @ @ @ @ @ @ @ dorsal exoskeleton shown by the integrity of the dorsum relative to soft anatomy ; a non-cuticularized ventral sole ; and iterated structures ; as well as the ( inferred ) presence of an anterior radula .
Butterfield ( 2006 ) disagreed with a molluscan affinity of Odontogriphus and Wiwaxia because a “ more detailed analysis of these fossil structures , however , reveals pronounced anatomical and histological discrepancies with molluscan analogues , such that they are more reliably interpreted as primitive features of the superphylum Lophotrochozoa.
” This author also remarked that contrary @ @ @ @ @ @ @ , “ no such traces are found in association with Odontogriphus or Wiwaxia , and , in any event , it is questionable whether a two-rowed ( or even a four-rowed ) feeding apparatus could work in any way analogous to a belt-like radula.
” Butterfield concluded that “ The dilemma of interpreting fossil ‘ worms ’ as molluscs or annelids — or for that matter brachiopods , chaetognaths , arthropods or chordates — is hardly new .
In some cases , the problem is simply a dearth of diagnostic features ( e.g @ @ @ @ @ @ @ can only be reliably identified as a probable bilaterian ) .
” Conway Morris & Caron ( 2007 ) considered two alternative positions for Kimberella and Odontogriphus , either as successive stem lophotrochozoans or as successive stem mollusks , but they preferred the former alternative as better supported by their cladistic analysis .
However , they admitted that the “ bootstrap values are generally very low and the most parsimonious tree is far from robust , ” which is just another way to say that the results are not well supported and thus @ @ @ @ @ @ @ ( 2007a ) simply listed Kimberella as a member of the phylum Mollusca , which “ may be related to living chitons ( amphineurans ) and monoplacophorans.
” Fedonkin et al .
( 2007b ) closed their abstract with the statement that “ the structural complexity of Kimberella poses questions about the time of origin of the triploblastic metazoans.
” They also compared many structures with those of mollusks and concluded that Kimberella had a “ fundamentally mollusc-like architecture.
” Budd ( 2008 ) said that the claim for a bilaterian affinity of @ @ @ @ @ @ @ discovery of the molluscan affinities of the rather similar Odontogriphus from the Burgess Shale ” ( Butterfield 2006 , Caron et al .
2006 ) .
Butterfield ( 2008 ) described isolated microscopic teeth from the early Cambrian Mahto Formation in Alberta ( Canada ) , which he identified as components of a molluscan radula and the oldest fossil record of this structure .
He showed that similarities with the feeding apparatus of the Cambrian organisms Odontogriphus and Wiwaxia are only superficial .
Concerning Kimberella he said : “ Tellingly , Caron et @ @ @ @ @ @ @ identification of radula-bearing fossils to Late Ediacaran Kimberella based solely on the presence of co-occurring sedimentary scratch marks , whereas Conway Morris and Caron ( 2007 ) argue that both Kimberella and Odontogriphus are just as likely to represent stem-group lophotrochozoans ( despite coding both forms as having a ‘ muscular foot ’ and ‘ distichous radula ’ ) .
Whether Kimberella , Orthrozanclus , or Halkieria … had a radula remains to be seen ….
” Parkhaev ( 2008 ) mentioned that Kimberella “ was interpreted as a primitive mollusc-like organism ” @ @ @ @ @ @ @ Kimberella with traces of crawling ( Figure 3.1B ) prove the animal nature of this organism and favor its molluscan affinity , ” but cautioned , “ however , to determine whether Kimberella is really a mollusc , specimens are needed that show a defined head with a ventral mouth.
” Peterson et al .
( 2008 ) noted that “ one taxon in particular , Kimberella , has generated much discussion as a possible triploblastic metazoan.
” Based on several similarities with mollusks ( i.e .
external form , inferred radula-like organ @ @ @ @ @ @ @ well as their molecular clock estimate of a divergence between annelids and mollusks about 570 million years ago , the authors concluded that “ it is possible , if not probable , that Kimberella is allied with modern molluscs.
” Davidson & Erwin ( 2009 ) discussed the usual characters ( body size and shape , apparently muscular foot , associated scratch marks ) , but cautioned that “ Although many of these features are similar to those of a mollusk … , it is probably premature to assign Kimberella to the Mollusca.
@ @ @ @ @ @ @ fossil so far only Kimberella “ shows convincing bilaterian characters ” and “ can reasonably be considered as representing a protostome.
” More specifically they claimed that Kimberella “ marks the first appearance of a lophotrochozoan lineage ” and represents the only Ediacaran organism that “ clearly lies above the protostome–deuterostome divergence , ” which therefore must predate 555 million years .
They also thought that “ the appearance of Kimberella and the oldest metazoan traces at this time is unlikely to be a coincidence.
” Ivantsov ( 2009 ) concluded that “ @ @ @ @ @ @ @ some very early stage in the evolution of trochophore animals , may be even to the proto-molluscan stage.
” Xiao & Laflamme ( 2009 ) said that Kimberella “ has the best phylogenetic resolution so far ” as a bilaterian animal “ and is interpreted as possible mollusc.
” Rozhnov ( 2010 ) mentioned that “ Some Vendian organisms , primarily Kimberella probably had a higher level of organization , judging from its more complex structure and traces of feeding … However , even this quite exceptional case can not be unequivocally interpreted @ @ @ @ @ @ @ organized than would be required by their supposed molluskan level of organization.
” Seilacher & Hagadorn ( 2010 ) discussed Kimberella as “ early bilaterian ” and “ earliest mollusks.
” They thought that the “ fan-shaped scratches — perhaps more than the inferred morphology of Kimberella or the early Cambrian appearance of radular teeth … indicate that such key crown-group mollusk features as a radula and muscular foot had already evolved before the Cambrian .
This also implies that Lophotrochozoa , in which Mollusca are nested … had already originated by this @ @ @ @ @ @ @ that even though Kimberella is believed to be a proto-mollusk , “ the anatomy of Kimberella , as currently understood , is rather distant from typical mollusks and this introduces some uncertainty regarding its widely accepted identity as a pre-Cambrian member of the Spiralia.
” He also discussed a possible relationship with the mollusk-like Cambrian genera Halkieria , Wiwaxia , and Odonatogriphus .
Erwin et al .
( 2011 ) considered Kimberella as “ confidently assigned to the crown of Metazoa ” and as “ bilaterians , and possible molluscs.
” They erected @ @ @ @ @ @ @ and the somewhat similar genus Solza .

Photo: Dorsal mold of Kimberella quadrata from the Ediacaran of Russia, showing the cuticular dorsal shield with tubercular nodes and the tapered oral end; by Aleksey Nagovitsyn: Wikimedia, GNU FDL).
Editor’s note: We are delighted to present a series of posts by paleontologist Günter Bechly on the Ediacaran organism Kimberella. If identified as an animal, it would “predate the Cambrian explosion of bilaterian animal phyla as a kind of ‘advance guard.’” The question is of interest for debates about evolution and arguments about intelligent design raised by Stephen Meyer, among others. Find the full series about Kimberella here.
Glaessner & Daily (1959) figured a specimen of Kimberella as a “problematic fossil, possibly belonging to the Siphonophora.”
Glaessner & Wade (1966) compared Kimberella with Leptomedusae, Trachymedusina, and Carybdeida (Cubozoa or box jellies). They agreed that “the existence of most of its characters in one or more of these groups indicates its medusoid affinities.” Their main argument was an assumed homology of the apparent “segmented zones” with the gonads in some jellyfish groups.
Wade (1972) discussed the assumed medusoid affinities, agreed with the interpretation of the segmented zones as medusoid gonads and gastric pouches, and even believed themselves to see possible tentacles. Wade suggested that Kimberella is “probably a Scyphozoan” (true jelly).
Pure Fantasy
Jenkins (1984, 1992) thoroughly reviewed and reevaluated the morphology of Kimberella and came to somewhat different interpretations (e.g., concerning the puckered gonads) but also concluded that a medusoid affinity is obvious. He described in detail for Kimberella the presence of medusoid organs like the bell, 2-3 puckered gonads, subumbrella, rhopalia, and pedalia supporting the tentacles. He suggested that Kimberella is a cubozoan box jelly and even is the direct ancestor of the modern chirodropid sea wasps, which are responsible for many severe accidents for swimmers on the Australian coast. Such a cubomedusoid affinity was also endorsed by Glaessner (1984). It is remarkable, indeed, how detailed a medusoid morphology was projected onto Kimberella fossils and later recognized as pure fantasy.
After the new and better preserved White Sea material was discovered in 1994 and described by Fedonkin & Waggoner (1997), Fedonkin (1998), and Waggoner (1998), these authors totally rejected the previous medusoid interpretation of Kimberella and found that this fossil organism “had no tentacles, no tetraradiate symmetry, and no bell.” They also rejected a possible affinity with the more typical Ediacaran organisms. Instead they interpreted Kimberella as “a bilaterian, more complex than a platyhelminth [flatworm], and more like a mollusk than anything else living.” Nevertheless, Fedonkin & Waggoner offered the qualification, “We cannot prove a molluscan affinity conclusively; some definitive molluscan synapomorphies, like the radula, cannot be seen, and others are open to other interpretations.”
Seilacher (1997, 1999) thought that the trace fossils “record a bilateral radula and its usage in pendulum grazing, which is definitely a molluscan feature … as is the impression of a broad muscular foot.” Seilacher (1999) speculated that “the Kimberella animal could have been a halkieriid,” which is a mollusk-like Cambrian organism. Independent of its affiliation, however, he thought that it could be properly modeled after modern “soft limpets.”
Erwin (1999) was very skeptical of previous attributions of Ediacaran organisms to animals. He said that “those who would assign Ediacaran fossils to protostomes and deuterostomes have generally failed to identify any diagnostic characters which unambiguously support such assignments. At present then, claims of a higher metazoan affinity must be regarded as unproven.” Nevertheless, he characterized Kimberella as “triploblastic, benthic organism with a broad, well-muscled foot and a broad visceral cavity. Such an organism would have required at least a hemaeocoel. No appendages are present (as is true of all Ediacaran forms) nor is a mouth apparent.” He said that “although this is not clearly a mollusc (Fedonkin and Waggoner’s preferred interpretation) or even a protostome, it is more complex than a cnidarian” and “Kimberella could also represent a stem-group bilaterian” before the protostome-deuterostome ancestor.
Budd & Jensen (2000) commented as follows: “Perhaps the strongest case for an Ediacaran bilaterian body fossil has been made by Fedonkin & Wagonner [sic] (1997) for Kimberella, which they describe as mollusk-like. It is a relatively large, bilaterally symmetrical organism, which they reconstruct as possessing both a dorsal shell and a ‘foot’. Nevertheless, Kimberella does not possess any unequivocal derived molluscan features, and its assignment to the Mollusca or even the Bilateria must be considered to be unproven (cf. Erwin, 1999).”
Martin et al. (2000) called Kimberella the “oldest well-documented triploblastic bilaterian,” but still admitted that “whether Kimberella at 555 Ma indicates that the protostome-deuterostome split is even older is not yet resolvable.”
Erwin & Davidson (2002) considered Kimberella as “the oldest generally accepted bilaterian fossil” and “oldest convincing remains of bilaterians are fossils of an already well-developed animal” and “demonstrable adult bilaterian form.” Furthermore, they said that Kimberella “is interpreted as a benthic animal, most likely of protostome affinity, and possibly a mollusk.”
An Artifact of Fossilization
Dzik (2003) did not consider the Kimberella fossils as ventral casts but rather as “external molds of the collapsed upper surface of the body.” Therefore, he claimed that the similarity to limpet soles is quite superficial and rather an artifact of the fossilization process. He also said that “the main argument for the molluscan nature of Kimberella remains thus its association with putative radular marks proposed by Seilacher (1999). However, it is unclear what these structures truly represent.” Instead, Dzik thought that the stable width between supposed gut and the body surface was filled with a kind of mesoglea and mesogleal muscles, which “would point to ctenophoran affinities of Kimberella.” He therefore interpreted Kimberella as a freely swimming animal and possible comb jelly.
Fedonkin (2003) of course affirmed the “new interpretation of Kimberella as a mollusk-like triploblastic animal.”
Seilacher et al. (2003, 2005) called Kimberella a “soft limpet” and “primitive mollusk,” and said that “the molluscan nature of Kimberella is expressed by impressions of the flat foot and the margin of a soft dorsal shield seen in ventral deathmasks of the bodies,” which he obviously considered as putative synapomorphies.
Valentine (2004) listed Kimberella as “a possible eutrochozoan” and “a mollusc-like bilaterian organism.” However, this author also commented that “although Kimberella is interpreted as having a cap-shaped shell, there is evidence only of a relatively rigid dorsal region, and assignment to Mollusca is based on general similarity of form.”
Mainly based on Fedonkin & Waggoner (1997), Caron et al. (2006) considered Kimberella as an earliest stem group mollusk, succeeded by the Lower Cambrian stem group mollusks Odontogriphus, Wiwaxia, and Halkieria. These authors especially mentioned the following commonalities between Kimberella and the soft-bodied organism Odontogriphus: dorso-ventrally flattened ovoid shape; large size; a cuticular dorsal exoskeleton shown by the integrity of the dorsum relative to soft anatomy; a non-cuticularized ventral sole; and iterated structures; as well as the (inferred) presence of an anterior radula.
Butterfield (2006) disagreed with a molluscan affinity of Odontogriphus and Wiwaxia because a “more detailed analysis of these fossil structures, however, reveals pronounced anatomical and histological discrepancies with molluscan analogues, such that they are more reliably interpreted as primitive features of the superphylum Lophotrochozoa.” This author also remarked that contrary to the Kimberichnus traces attributed to Kimberella, “no such traces are found in association with Odontogriphus or Wiwaxia, and, in any event, it is questionable whether a two-rowed (or even a four-rowed) feeding apparatus could work in any way analogous to a belt-like radula.” Butterfield concluded that “The dilemma of interpreting fossil ‘worms’ as molluscs or annelids — or for that matter brachiopods, chaetognaths, arthropods or chordates — is hardly new. In some cases, the problem is simply a dearth of diagnostic features (e.g. Kimberella, which on current evidence can only be reliably identified as a probable bilaterian).”
Two Alternative Positions
Conway Morris & Caron (2007) considered two alternative positions for Kimberella and Odontogriphus, either as successive stem lophotrochozoans or as successive stem mollusks, but they preferred the former alternative as better supported by their cladistic analysis. However, they admitted that the “bootstrap values are generally very low and the most parsimonious tree is far from robust,” which is just another way to say that the results are not well supported and thus not reliable.
Fedonkin et al. (2007a) simply listed Kimberella as a member of the phylum Mollusca, which “may be related to living chitons (amphineurans) and monoplacophorans.” Fedonkin et al. (2007b) closed their abstract with the statement that “the structural complexity of Kimberella poses questions about the time of origin of the triploblastic metazoans.” They also compared many structures with those of mollusks and concluded that Kimberella had a “fundamentally mollusc-like architecture.”
Budd (2008) said that the claim for a bilaterian affinity of Kimberella “has been revitalized by the discovery of the molluscan affinities of the rather similar Odontogriphus from the Burgess Shale” (Butterfield 2006, Caron et al. 2006).
Butterfield (2008) described isolated microscopic teeth from the early Cambrian Mahto Formation in Alberta (Canada), which he identified as components of a molluscan radula and the oldest fossil record of this structure. He showed that similarities with the feeding apparatus of the Cambrian organisms Odontogriphus and Wiwaxia are only superficial. Concerning Kimberella he said: “Tellingly, Caron et al. (2006) extend their identification of radula-bearing fossils to Late Ediacaran Kimberella based solely on the presence of co-occurring sedimentary scratch marks, whereas Conway Morris and Caron (2007) argue that both Kimberella and Odontogriphus are just as likely to represent stem-group lophotrochozoans (despite coding both forms as having a ‘muscular foot’ and ‘distichous radula’). Whether Kimberella, Orthrozanclus, or Halkieria … had a radula remains to be seen ….”
Parkhaev (2008) mentioned that Kimberella “was interpreted as a primitive mollusc-like organism” and that “the recent finds of Kimberella with traces of crawling (Figure 3.1B) prove the animal nature of this organism and favor its molluscan affinity,” but cautioned, “however, to determine whether Kimberella is really a mollusc, specimens are needed that show a defined head with a ventral mouth.”
Peterson et al. (2008) noted that “one taxon in particular, Kimberella, has generated much discussion as a possible triploblastic metazoan.” Based on several similarities with mollusks (i.e. external form, inferred radula-like organ, association with scratch marks) as well as their molecular clock estimate of a divergence between annelids and mollusks about 570 million years ago, the authors concluded that “it is possible, if not probable, that Kimberella is allied with modern molluscs.”
Davidson & Erwin (2009) discussed the usual characters (body size and shape, apparently muscular foot, associated scratch marks), but cautioned that “Although many of these features are similar to those of a mollusk …, it is probably premature to assign Kimberella to the Mollusca.” They concluded that among the Ediacaran fossil so far only Kimberella “shows convincing bilaterian characters” and “can reasonably be considered as representing a protostome.” More specifically they claimed that Kimberella “marks the first appearance of a lophotrochozoan lineage” and represents the only Ediacaran organism that “clearly lies above the protostome–deuterostome divergence,” which therefore must predate 555 million years. They also thought that “the appearance of Kimberella and the oldest metazoan traces at this time is unlikely to be a coincidence.”
Freeman (2009) commented that “another bilaterian, Kimberella, is a putative stem group mollusc.”
Ivantsov (2009) concluded that “most likely, Kimberella was related to some very early stage in the evolution of trochophore animals, may be even to the proto-molluscan stage.”
Xiao & Laflamme (2009) said that Kimberella “has the best phylogenetic resolution so far” as a bilaterian animal “and is interpreted as possible mollusc.”
Ivantsov (2010b, 2011) considered Kimberella as a “trochophore animal of a pre-molluscan stage.”
Rozhnov (2010) mentioned that “Some Vendian organisms, primarily Kimberella probably had a higher level of organization, judging from its more complex structure and traces of feeding … However, even this quite exceptional case cannot be unequivocally interpreted. Anatomically they could be more simply organized than would be required by their supposed molluskan level of organization.”
Seilacher & Hagadorn (2010) discussed Kimberella as “early bilaterian” and “earliest mollusks.” They thought that the “fan-shaped scratches — perhaps more than the inferred morphology of Kimberella or the early Cambrian appearance of radular teeth … indicate that such key crown-group mollusk features as a radula and muscular foot had already evolved before the Cambrian. This also implies that Lophotrochozoa, in which Mollusca are nested … had already originated by this time.”
A Possible Relationship
Dzik (2011) wrote that even though Kimberella is believed to be a proto-mollusk, “the anatomy of Kimberella, as currently understood, is rather distant from typical mollusks and this introduces some uncertainty regarding its widely accepted identity as a pre-Cambrian member of the Spiralia.” He also discussed a possible relationship with the mollusk-like Cambrian genera Halkieria, Wiwaxia, and Odonatogriphus.
Erwin et al. (2011) considered Kimberella as “confidently assigned to the crown of Metazoa” and as “bilaterians, and possible molluscs.” They erected a new clade Kimberellomorpha to accommodate Kimberella and the somewhat similar genus Solza.
Next, “Kimberella and Controversial Relationships — A Chronological Synopsis, Continued.”