Confounded Dolphin Teeth: More From the Chronicles of the Demise of My Fossil Collection

Many of the fossils I painstakingly collected over the years have entered into a curious limbo, resting now in gallon-sized plastic baggies that are distinguished only by general category of fossil (teeth, shells, etc.) and where found.  These fossils await a final disposition though I do know they won’t be kept.  (My previous post described what a poor job I did of curating the bulk of the collection.)  So far, a few fossils have resisted the deconstruction process as I’ve filled these large bags.  The pufferfish fossils highlighted in the previous post are one example.  A second group of fossils has managed to distract me and avoid the fate of those fossils in the big baggies.  This is a small clutch of tiny dolphin teeth collected along the shoreline of the Calvert Cliffs where the Calvert Formation is exposed (the portion of that formation yielding these teeth dates from possibly a bit less than 17 to about 14 million years ago).  I initially set them aside for two reasons:  I find them beautiful in their simplicity and, until now, I had never attempted to try and assign them to Miocene dolphin genus and species.  (Clearly, decommissioning my fossil collection will take forever if this is going to be my usual pattern of behavior.)

[Later edit:  Is it possible there are bony fish teeth mixed in with these?  I don't think so, but that would definitely confound this exercise even more.]

This post is focused on this effort in taxonomy and (to end any suspense) why it was a failure, despite the apparent diversity in teeth shown above.  I will acknowledge at the outset that much of that "diversity" is likely due to how worn these teeth are.  Nevertheless, there's a bit of a story about dolphin teeth to be told.

Some initial groundwork with terminology and relationships is necessary.  The cetaceans (commonly slapped with the general label whales) are divided into two main groups.  The odontocetes or toothed whales are a taxon which also includes dolphins and porpoises.  The other large category of cetaceans are the mysticetes or baleen whales.  Another point of clarification.  The small cetacean teeth I collected from the Calvert Cliffs shoreline are most likely from dolphins and should not be ascribed to porpoises:  the latter, extant from perhaps the mid Miocene onward, were denizens of the Pacific, and, reportedly, their fossils are particularly scarce prior to the Pleistocene.  (For more on this issue concerning porpoises, see text by Joy Pierce Herrington, in Fossil Marine Mammals (Digital Version), Volume IV of IV - Part 2, North Carolina Fossil Club, edited by Richard Chandler, 2017, pages 6, 118.)

Early on in this taxonomic endeavor, I was encouraged by learning of the recent publication of a superb description of the various toothed whales of the Calvert Cliffs written by paleontologists Stephen J. Godfrey and Olivier Lambert.  (Miocene Toothed Whales (Odontoceti) from Calvert Cliffs, Atlantic Coastal Plain, USA, Chapter 2 in The Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA, Volume 2, Turtles and Toothed Whales, edited by Stephen J. Godfrey, Smithsonian Contributions to Paleobiology, Number 107, 2023.)  It is an expansive treatise on these odontocetes, including discussions and descriptions of 16 dolphin species whose fossils have been found in material shed from the portion of the Calvert Formation along which I collected my dolphin teeth.  (This count is based on Figure 2.73 which lists the named odontocetes by stratigraphy.  I have assumed, possibly in error, that Shattuck-Zones 8 to 13 are responsible for my teeth.)

Yet, this volume, for all of its many merits, turns out to be a thin reed (at least for me) upon which to attempt any extensive taxonomic attribution of the dolphin teeth I have on hand.  I went so far as to create a spreadsheet listing each of the dolphin species described by Godfrey and Lambert, excerpting any text about, or pictures featuring, teeth.  A few of the authors’ descriptions and images prompted one or two rash and wild guesses as to identity, but I ultimately concluded not to suggest any.  Discretion is by far the better part of valor in this instance.  Beyond the Godfrey and Lambert volume, I searched extensively elsewhere for some sort of single guide to fossil dolphin teeth, something similar to the many volumes devoted to fossil shark teeth, and came up empty.  Clearly, I hoped someone had done the heavy lifting in creating such a guide.

There are several key reasons why my taxonomic exercise failed.  I have already mentioned the evident wear and tear on my specimens.  But, in reality, at the heart of my difficulties is the profound impact of evolution on the earliest harbingers of the cetacea that made their way from the land back to the water.  Dolphins, like all of the other toothed whales, evolved from mammals that had typically mammalian teeth with highly varied morphology.  Consider the differences among the teeth in your own mouth.  Over time, as the stem odontocetes evolved to become fully aquatic, their teeth changed markedly.  I was quite taken by a paragraph on these evolutionary changes to their teeth written by paleontologist Steve Brusatte in his terrific book The Rise and Reign of the Mammals:  A New History From the Shadow of the Dinosaurs to Us (2022).

Gone are all the complex cusps and ridges; gone is the lineup of incisors, canines, premolars, and molars; gone is the replacement of baby teeth with adult teeth; gone is the ability to chew.  Instead, all the teeth are conical pegs, which simply cut meat off fish or other whales, which the odontocete then swallows.  Some odontocetes barely use their teeth in feeding and lazily swallow their prey whole.  (p. 280)

I drew three key conclusions from Brusatte’s overview of the changes that occurred.

First, the end result of the process is, in his words, “conical pegs.”  Yes, the conical or peg-like aspect to all of these teeth renders them relatively indistinguishable without close study.  This is unlike fossil shark teeth which come in a plethora of different shapes and sizes which are key to sorting them by genus and species, a task relatively easy for some of them.  (By the way, the teeth of porpoises are not conical but, rather, spatulate or cupped at their end.)

That said, there is in fact some diversity in the dolphin teeth that could be found along the Calvert Cliffs.  At the most extreme, there are the teeth from the three species of the Squalodontidae family that are present here.  The squalodons or, as they are sometimes called, “shark toothed dolphins,” have very distinctive teeth.    Consider those depicted below which appeared in the Godfrey and Lambert volume (figure 2.2, scale bar is 10mm).

Certainly, a couple of these are nothing like the Calvert Formation dolphin teeth in my collection.

Godfrey and Lambert do identify a few potentially distinguishing features of the teeth of several other dolphin species, ranging from tiny cusplets to keels running down the teeth.  Nevertheless, given the state of my dolphin teeth and the inherent "sameness" of nearly all such teeth, I don’t feel I have the necessary guidance I need to go further.  Frankly, it's true that, by and large, Miocene odontocete teeth (other than those from squalodons) are reasonably and justifiably covered by Brusatte’s descriptive phrase “conical pegs.”  Further, isolated odontocete teeth (excepting those of squalodons) are seldom appropriately diagnostic as to genus or species.  This specific point is made quite convincingly by a paleontologist on the discussion site The Fossil Forum in an exchange of messages regarding a search for ID guides to odontocete teeth.  He posted on June 11, 2013:  "I have one piece of advice for you:  Prepare for failure and disappointment.  The general attitude amongst marine mammal researchers is that, with the exception of really distinctive species, isolated odontocete teeth are generally not identifiable even to the genus level, and often not even to the family level. . . .  Odontocete teeth do not preserve the same breadth of diagnostic information that shark teeth have."

A second point to be made from Brusatte’s description is that it suggests that teeth in the jaws of odontocetes are homodont, that is, they do not really vary in morphology by location on the maxilla or mandible – top, bottom, front, or back of the jaws, the teeth are all similar, which they generally are.  Godfrey and Lambert label the teeth of odontocetes (other than squalodons) as “roughly homodont.”  This works to reinforce the sameness of the fossil dolphin teeth we might find along the shoreline.

(As an aside, at this point it strikes me that, were dolphins cartilaginous like sharks, that is, not having a bony skeleton, the work of paleontologists like Godfrey and Lambert would be incredibly more difficult.  Having the remains of bony skeletons to aid in determining genus and species makes a critical difference.)

Finally, Brusatte noted that, in the course of their lives, odontocetes have a single set of teeth.  The impact of this on the relative abundance of odontocete teeth fossils is significant.  I’ll acknowledge that some Miocene dolphins and extant dolphins are very much polydonts, that is, they have many teeth, some species a couple of hundred or more.  Nevertheless, when one considers that an individual shark might in its life span shed tens of thousands of teeth, it’s no wonder shark teeth litter the shoreline along the Calvert Cliffs, while dolphin teeth don’t.

All of this adds up to what I found to be insurmountable hurdles for assigning the teeth I have to genus, much less species, and helps explain the "missing" guide to fossil odontocete teeth.

In conclusion, although I won't be assigning my dolphin teeth to genus and species and, as a result, they will remain unknown, I will assign them to the “keep” category.  Beauty, simplicity, and relative scarcity win out.  So, a bunch of teeth that I can only assign to a collecting location and the broad category of “dolphin teeth,” nevertheless avoids the bardo to which I’ve condemned many fossils from my collection, some of which could be identified.  Quite ironic!

From the Chronicles of the Demise of My Fossil Collection: Revelations of Some Pufferfish Fossils

I began writing this blog in December, 2008, a year or two after I started seriously collecting fossils.  Over the years I wrote about a wide range of topics related to paleontology and natural history, but I focused frequently (though much less so recently) on my adventures in collecting.  This post signals that I am into a new phase in my fossil collecting:  its endgame.

As part of a general downsizing of home and possessions, I am dismantling the bulk of my fossil collection.  My sense of regret over the process is prompted not so much by the dispersal of the fossils, but rather by the choices I made over the years for the collection, particularly how I stored and identified what I collected.  In the course of breaking things down, I came upon three fossils collected over 15 years ago (just prior to beginning this blog and early in my collecting); what they say about my collection is the focus of this post.

Here is the first of those fossils, a spindle-shaped piece of fossilized bone.

It came out of a drawer in one of the many small organizer cabinets (designed originally for workbench items like nails and screws) that housed much of the collection.  Overall, these drawers held more than a thousand baggies, often with more than a single fossil inside.  This specific bag shares one specific feature with nearly all of the others:  a label that identifies location and date of collection.  Where it differs from most of the bags is that the specimen inside is clearly not a shark tooth.

I did much of my collecting in a very few locations:  the western shoreline of the Chesapeake Bay, Maryland (fossils date from a swath of the Miocene Epoch, say roughly 18 to 8 million years ago); the shoreline of the Potomac River at Purse State Park, Maryland (fossils here are from the late Paleocene Epoch, about 59 to 56 million years ago); and a creek bed at Science Drive, Maryland (the hard-won fossils here date from perhaps 74 to 66 million years ago in the late Cretaceous Period).

According to the label on the bag shown above, I collected the fossil at the Lee Creek Mine, North Carolina, which, when we could collect there, yielded beautiful fossils from the Miocene, Pliocene, and Pleistocene Epochs, from perhaps about 14 to 1.5 million years ago.  I entered the mine (not quite what it sounds like given that the mine is a working surface phosphate mine) on Sunday, October 12, 2008, a truly remarkable occasion because I had gained access to this place considered quite holy by fossil collectors.  A picture I took that day shows the scene with a scattering of collectors in pursuit of treasures.

From this landscape of hills of grey sand punctuated by wide pools of dark water could come an amazing array of fossils, none more sought after than the teeth from the shark Carcharocles megalodon (the roots of its species name are Greek and, appropriately, mean “giant tooth”).  I didn’t find any meg teeth that day, but did find an array of wonderful fossils.  The bone in this bag was one of them but, over the years, I’d forgotten all about it.  It fell victim, in part, to the lapses of an aging memory and to how I curated my collection. 

The reason for all of the baggies among which this particular fossil bone lay hidden is a choice I made early on:  obsessively record when I collected a fossil.  The drawers were organized primarily by the location where fossils were found and secondarily by the kind of fossil (e.g., tooth or shell).  As a result, if I had many fossils from a particular location (certainly true for those I visited repeatedly over the years) and, even if many of the fossils were largely indistinguishable (to wit, any one sand tiger tooth is much like any other – identifying genus and species is often a chore), the specimens ended up in a multitude of bags distinguished only by collecting date, a piece of information that, in retrospect and despite the pleasant memories stirred up by what took place on the date on this bag, is largely meaningless.

When this piece of bone reemerged, after being long lost in the collection and in the mists of my memory, I took what had been the usual first step in identifying a fossil from the Lee Creek Mine:  page through Neogene and Quaternary Fossils of North Carolina:  A Field Guide, prepared by Richard Chandler (text) and John Timmerman (illustrations), published by The North Carolina Fossil Club.  Although the copy I currently have at hand is the 2011 revised edition, I once owned the 1994 edition of this guide and must have used it in 2008 when I got home from the mine.  This is an excellent and very handy publication; each of the fossils covered is nicely illustrated and identified.  There, on page 31 of the current edition, under the title Common Bony Fish Fossils, is a drawing of the very fossil in my bag along with several others.  (The image below of this portion of page 31 is included here with the kind permission of the guide’s authors.)

The spindle-shaped fish specimen in question is identified as a ventral postcleithrum.  The other fossils depicted are cited as suboperculum, preoperculum, and operculum.  The placement of the label “Sphoeroides hyperostosus (Pufferfish) Gill Plates” is a bit misleading because only the latter three bones, not the postcleithrum, are gill plates.  What is true is that all four of these fossils are abundant in the Lee Creek Mine and all come from S. hyperostotus (more on that below).  (In a private communication, one of the authors noted that a future edition would address the issue of that label placement.)

The effort to identify this once lost Lee Creek fossil exploded into a host of related (and semi-related) questions and issues.  Among the most immediate:  Pufferfish?  What is a ventral postcleithrum?  What are gill plates?  Doesn’t the fossil illustrated in the upper left of this display, identified as a suboperculum, look familiar?

Zoologist Katherine Ellott Bemis writes that “pufferfishes and their relatives are some of the most diverse fishes in terms of anatomy and natural history.”  (Pufferfishes and Their Relatives, Smithsonian, National Museum of Natural History, Ocean Life, January 2023.)   Their diversity extends to size, color, and defense mechanisms.  They are well known for their ability to defend themselves by inflating their body and extending spines, and for the lethal toxicity of some species.

In bony fish (which include pufferfish, extinct and extant), a gill plate is a bony flap, called the operculum, that covers the gills on either side of the fish, affording protection for the gills and aiding in respiration.  Generally, the operculum is a mosaic of several bony pieces (the opercular series) consisting of the preoperculum, suboperculum, interoperculum, and operculum.  I assume this last bone carries the same name as the full array of bones because it’s the one in the series that actually covers the gill chamber.

I should note that, after plowing through many detailed and tedious research articles about fish gill plates, I found the most cogent summary to be a piece by a former librarian and “pet enthusiast”  Kathryn Copeland titled What is the Function of the Operculum on a Fish?  It appears on the website:  ZooNerdy and was updated October 21, 2023.  I regret that she did not cite the underlying sources for the information she conveys.  That said, her piece squares with what I managed to understand from the research literature I plowed through.

I am puzzled about the postcleithrum which is not part of the opercular series and so is not a gill plate.  I believe it to be part of another series of bones running from the area of the pectoral fin to the cranial area.  My effort to find an accessible discussion of this bone and its function has so far been fruitless.  

Sphoeroides hyperostosus, the species cited by the North Carolina fossil guide, was named in 1992 by J.C. Tyler et al. based on a partial skull found at the Lee Creek Mine in the Yorktown Formation (Pliocene Epoch).  (A New Species of Sphoeroides Pufferfish (Teleostei: Tetraodontidae) with Extensive Hyperostosis from the Pliocene of North Carolina, Proceedings of the Biological Society of Washington, Volume 105, Number 3, 1992.)  This was a particularly important find because several of the bones in the skull were hyperostotic (i.e., swollen), a condition that prompted the authors to give the fossil its species name.  Tyler et al. assigned all of the kinds of bones depicted in the illustration from the North Carolina fossil guide to S. hyperostosus, distinguishing ventral postcleithrum bones from opercular bones.

The disarticulated hyperostotic opercular bones that are so common at Lee Creek Mine can reasonably assumed to be from S. hyperostosus because of their similarity to those from the Lee Creek skull.  We presume that the disarticulated ventral postcleithra from Lee Creek Mine are also from S. hyperostosus because it is the only species of Sphoeroides (and tetraodontid) known from Lee Creek and the disarticulated ventral postcleithra in general are similar to those of most species of Sphoeroides. (p. 463)

Until the work by Tyler and his colleagues, identification of source of these fossils had been problematic.  Now it was shown that all of these swollen bones were from an extinct species of pufferfish and that the condition of these bones was, as the authors concluded, “normal.”

As for my sense that I somehow already knew the suboperculum, it was a relief when, after some searching, I found a small plastic case (shown below) in the back of a drawer in the wooden cabinet that houses some of my better small fossils.

Of course, would it not have been logical and appropriate that, when these suboperculum bones graduated to the wooden cabinet housing my nicer pieces, they would have carried labels delineating not just collecting location and date, but also genus and species (given that I presumably knew them)?  But, no.  As the picture clearly shows, these two fossils were labelled simply “NS10-11.”  No other information, not even the bits I was most consistent in assigning to my specimens.  Tyler et al. had stated that S. hyperostosus was “known only from the Lee Creek locality” (p. 463), so that was most likely the source of these fossils.  Still, the differences in color and greater density that the black specimen exhibited raised real questions about its origin that only a deciphering of the alphanumeric data on the case could answer.  That process, described below, borders on being a separate shaggy dog story.

It took awhile but I finally recalled that at some stage, when I attempted to organize my collection digitally, I fed data into the Trilobase application (versions 6 and 7) using “NS” for “non-shark” (as these fossils certainly were).  Since nothing comes easily, that foray into the digital world was at least one, if not more, computers ago, forcing me to find backup disk drives for those earlier PCs.  Eventually I did come upon a file identified as “non-shark,” but at this point I couldn’t open it because I had no functioning version of Trilobase application.  After a bit more screwing around, I downloaded a copy of the program and opened the file.  There they were, entries for NS10 and NS11:

Don't bother trying to read the text of these entries (though they are quite legible inside the program), I will transcribe the relevant information from each of these pages.

For NS10, I wrote the following description:

Height Dim:  5/8"
Pufferfish suboperculum:  part of opercular series of bones that make up what are called gill plates
tan and very light weight, repaired

For its location, I wrote:

this was on the surface at Lee Creek and just seemed familiar -- I had already found a ventral postcleithrum (had no idea what it was) but recognized the shape -- it's also one of the gill plate bones

I entered a personal note for this fossil:

first fossil repair attempted

The date of collection was 10/12/2008. 

For NS11, I entered this description:

Height Dim:  3/4"
Pufferfish suboperculum (see description for NS0010)
this is black, passes clink test -- feels like rock -- NS10 doesn't which still has a porous bony feel to it

I noted its location as:

Green Mill Run - screening in the stream

I also entered a note on this specimen:

this struck a chord -- so similar to what I found the day before at Lee Creek 

The date of the collection was 10/13/2008

How could I have forgotten how incredibly useful the Trilobase program was?  Too bad I didn’t use it religiously.

The dates on which these two subopercula were found are telling.  It’s not really surprising that my collection contained specimens found on October 12, 2008, at the Lee Creek Mine, and specimens collected the next day at the Green Mill Run site at Greenville, NC, some 50 miles from the mine.  (The stream actually appears to be named Greens Mill Run, but I never heard it called that.)  Once collectors had made the trek to Lee Creek, nearby fossil sites were fair game.  Doing Lee Creek and Green Mill Run back to back was par for the course.  The latter offered a very different collecting experience.  That Monday, I walked the streambed, shoveling and sifting gravel in pursuit of teeth, and I was alone.  Here’s a picture from that day.

What is surprising to me is that the same kind of fossil I found at the mine, turned up at a site 50 miles to the northwest.  I’m inclined to say:  So much for the notion that S. hyperostosus is unique to Lee Creek.  That said, where exactly any Green Mill Run fossil actually originated is uncertain.  Fossils found here are a mixture of ones from the Cretaceous Period forward to the Pliocene Era because the stream cuts through various geological strata.  One of these is the Yorktown Formation, the same one yielding all those S. hyperostosus fossils at the Lee Creek Mine.

The Trilobase entries that I unearthed offer more evidence that the clerks in charge of my memory had misfiled other pieces of information related to these fossils.  When I created the entry for the Lee Creek suboperculum, NS10, I already knew that it was associated with a fossil I had found the same day, a ventral postcleithrum.  Clearly, I had done some research on both, beginning with the earlier edition of the North Carolina fossil guide.  And even more disillusioning, I separately uncovered evidence that, shortly after the Lee Creek foray, I engaged in a long, detailed exchange of messages on a fossil listserv, a discussion that covered these very fossils, their origin and identification.

When I lay out all that I learned recently about what happened and didn’t happen to these three fossils in my collection, my reaction is:  WTF?  I should be subject to a bill of particulars over failures in my stewardship of fossils.

Here are the most salient parts of that charge:  The majority of my fossils ended up in a seemingly limitless multitude of plastic baggies labelled with only the barest of information associated with any one of them.  Yes, I identified the postcleithrum bone collected at Lee Creek, but I never labelled it with that information, noting only location and date collected.  I also did not create a Trilobase entry for it.  Further, the baggie with that bone “disappeared” into one of a number of plastic drawers full of Lee Creek material in myriad bags.  As a result, it was separated from the two suboperculum fossils that might have given it some context.  In addition, at one point, I obviously felt that the two suboperculum bones were important because I created entries for them in Trilobase and engaged in an extended give and take on a fossil listserv about them.  Nevertheless, as further evidence of my malfeasance, when it came time to put them in the cabinet with the “good” stuff, I simply slapped an “NS10-11” on their case, as if that would make sense to someone who might come upon them later, including me.  This action was taken despite the fact that the Green Mill Run specimen may actually have some broader scientific interest because it belies the notion that S. hyperostosus is unique to Lee Creek.  (On this issue, see the note below.)

All of this is so bittersweet.  Among the sweetness are some good memories of fossil collecting trips and, I’ll admit, some pleasure from the research I pursued for this post (though it was often over ground I’d trodden years ago).  The bitterness comes from regret over those decisions made back when and the slapdash way I took care of my specimens.  That my recollection of the specifics associated with this trio of pufferfish fossils has proven difficult for my mental clerks to recover is quite disheartening.

I guess these are among the usual emotions stirred up by downsizing. 

Note
The online Paleobiology Database indicates two locations at which the extinct species S. hyperostosus has been found:  Lee Creek Mine in North Carolina and the Austin Sand Pit in South Carolina.  The only evidence for the latter is the mention of this species in a list of the fossil vertebrates purportedly found in the Pit.  The Paleobiology Database’s source citation for this list is a 2018 research paper in which I found with no description of either the origin or the process for compiling the list.

The Fish Are Dead, Long Live the Fish

It’s been a long time since I found a book as fascinating and as frustrating as Naming Nature:  The Clash Between Instinct and Science by biologist and science writer Carol Kaesuk Yoon.  Though it came out in 2009, I only recently tumbled to its existence (how it came to my attention is described later in this post).  

This account of the history of scientific taxonomy from Carolus Linnaeus (1707-1778) to the present had me engrossed from the outset even as I began muttering objections, not to the story per se that she tells it, but to the dire impact she ascribes to it.

In Yoon’s telling, taxonomy, the systemic categorizing of entities in the natural world, had its formal, scientific birth in the early 1700s with the publication of Linnaeus’ Systema Naturae, which, through its multiple editions, displayed his effort to identify and label all known plants and animals.  It is to Linnaeus that we owe the two-part nomenclature in use today which gives each species a unique name identifying genus and species.  His taxonomic system was based on the appearance of organisms, an understanding that species were immutable, and on his intuition about which were related to others.  Yoon writes, “He had, by his own example, validated the ancient notion that life should be ordered based entirely upon one’s individual perceptions.”  (p. 49)

In time, the original underpinnings of this system would be challenged and largely overthrown, a movement fueled initially by Darwin’s theory of evolution which revealed how much the natural world was in flux and that species are not fixed.  The goal of taxonomy changed, the order it depicted would come to be based on evolutionary relationships, a shift which, as related in Yoon's book, challenged most people's view of the world.  In essence, after Darwin (1809-1882), “what evolutionary history tells us must be grouped together and what a person perceives should be grouped together in the natural order need not correspond at all.”  (p. 76.)  Yoon describes the various phases that taxonomy went through following Darwin, from evolutionary taxonomy to numerical taxonomy to molecular taxonomy and to cladistics.  (More on the last shortly.)

A critical part of her thesis is that humans have a natural (evolution- and brain-based) drive to categorize and label what is found in the living world.  This innate impulse evolved in our earliest ancestors who, in order to survive, needed to use their senses to quickly identify and distinguish between what was benign and what was toxic in the world around them – which plants were edible or poisonous, which animals were prey or predator, and which fellow humans might be friendly or hostile.  Yoon posits, because our brains developed to provide us with this view of the world, we continue to want to make distinctions based on how we experience the world, using our particular constellation of senses.  This sensory perception of the world is called our umwelt, a concept at the heart of Yoon’s treatise.  (I wrote previously about the markedly distinctive umwelts of many different species of animals when I reviewed Ed Yong’s brilliant book, An Immense World:  How Animal Senses Reveal The Hidden Realms Around Us (2022).)

Yoon argues that the history of changes in scientific taxonomy following Darwin is largely an account of battles to separate it from the human umwelt, to make it truly scientific and grounded in evolution.  She writes that, in these fights, conscious or, often, unconscious adherence to our umwelt drove some taxonomists to hold tight to a classification system that treated species as definite and real, physical appearance as the best organizing principle, and intuition as a useful tool for organizing groups.  After all, that is what our umwelt tells us about the living world – appearances are critical and groups are fixed.  The taxonomists who adhered to those traditional methods based on general appearance of organisms fought the changes and lost.

The true villain in her piece are the cladists whose cladistic analysis (from the Greek clade meaning branch) came to the fore beginning in the 1970s, following the upheaval wrought by the numerical taxonomists (who drove as many different morphological characteristics as possible of different groups through computer algorithms to generate trees of relationships) and the molecular taxonomists (who relied on the study of what we cannot see – molecules – to determine the relationships among organisms).

Though Yoon describes cladistics, I had to look to additional sources to try and get a better grip on it.  Not sure I succeeded.  As I understand it, cladistics rejects general physical appearance as an organizing principle.  In this system, only shared derived characters, that is, evolutionary novelties that are unique to an ancestor group and passed down to descendants, should be used to identify the evolutionary affinity among different taxa.  A taxon that includes only those groups of organisms exhibiting the same evolutionary novelties is monophyletic, a clade.  A clade is a “natural taxon which is a group of organisms that exists in nature as a result of evolution.  Although there are many  possible groupings of organisms, only a few groupings comprise natural taxa.”  (E.O. Wiley, et al., The Compleat Cladist:  A Primer of Phylogenetic Procedures, University of Kansas Museum of Natural History, Special Publication No. 19, October 1991, p. 3.)  Groupings that are not clades may be considered “artificial” in this schema.

I found a discussion on cladistics that paleontologist Donald R. Prothero included in his book Bringing Fossils to Life:  An Introduction to Paleobiology (1998) useful.  He noted that hair and mammary glands are found only in mammals and, thus, are considered shared derived characters for all animals classified as mammals.  Other features, such as four limbs and backbones, are not helpful in separating mammals from vertebrates because these attributes are found in a multitude of other kinds of animals, originating in some ancestor species to all of these animals.  They can, however, be useful in identifying larger clades that include mammals, such as the vertebrates (which, in the graphic below, include sharks, frogs, and mammals).  (Prothero, p. 47-48.)  Here is a very simple cladogram reflecting this example (it is largely based on figure 4.2 in Bringing Fossils to Life, p. 48).

This cladogram is annotated to identify examples of evolutionary novelties (e.g., vertebrae) that arose in an unknown ancestor group and were inherited by descendants from that group.  These diagrams do not identify a specific ancestor group in which shared derived characters arose because, in practice, such a group likely will never be known.  Instead, the goal for such graphs is the identification of the evolutionary relationship among groups, that is, which cluster of groups form clades.

There’s the rub.  Cladistics “does away” with the so-called artificial groups of organisms, those groupings that are not truly clades.  In their drive to promote their taxonomic system, cladists were motivated to target their methodology on special groups of organisms whose demise as taxonomically valid groups were particularly stunning, groups that most of us outside of science and some within science had long held dear and, based on our umwelt, certainly real.  The cladists’ most celebrated and reviled “kill” which they promoted repeatedly may well have been that of fish which, as a group, is not a clade and so, according to cladistics, is artificial, in other words, “dead.”

The death of the fish was a special moment each time it was an enacted because it was as grating, as disturbing, as umwelt-insulting as possible. It was, in essence, a direct attack on whatever was left of the taxonomist allegiance to their antiquated instincts.  (Yoon, p. 259.)

The cladogram below, from The University of California Museum of Paleontology, shows the clade that consists of the ancestor group of all that we consider to be fish.  Its descendants sharing its evolutionary novelties are shown.  Unfortunately, among all these fish is a group (highlighted in yellow) that includes animals we certainly don't identify as fish:  tetrapods.  Tetrapods are four-limbed organisms which include myriad groups such as mammals and, thus, us.  As a result, cladistics posits that fish, as the group is typically perceived, is not a valid clade because it excludes the tetrapods and their descendants.  To make fish a valid evolutionary group, we have some less than satisfactory options.  We might decide to include the tetrapods, thereby making us fish.  We might remove the tetrapods, but, to do so, we would have to drop all of the animals that are shown to the left of the lobe-finned fishes and tetrapods in the cladogram, i.e., the hagfish, lampreys, sharks, and rays.  And, so, fish are dispensed with by the cladists.

(The cladogram above is from A Fisheye View of the Tree of Life:  What Is a Fish?, part of the University of California Museum of Paleontology’s Understanding Evolution website.  It is reproduced under the Attribution-NonCommercial-Sharealike 4.0 Creative Commons License.)

It’s a fascinating story that Yoon tells, this conflict between an increasingly evolutionary-based taxonomy and the innate, human umwelt that sees the order of the natural world in mostly Linnaean terms.  Most of the objections I had as I followed her narrative centered on how much she engages in hyperbole to oversell the apparent impact on the rest of us (those outside of science) of the triumph of the cladists.

In her telling, most of the ills that currently plague the human relationship to the natural, living world stem from that separation of the scientific view of that world from that of the human umwelt.  She posits, “Taxonomists abandoned their umwelt, and we did so along with them.”  (p. 283.)  People, she argues, stopped caring about the living world largely because, as defined by the cladists, the natural order no longer squared with our umwelt.  As a result, gone were the amateur naturalists who could name a multitude of butterflies or beetles and, in their stead, have come consumers who can cruise the malls and identify myriad products on the basis of their logos.  As this has been happening, the natural world has been under siege with species disappearing at an accelerating and alarming rate and, she posits, we do not care because science has turned its back on our umwelt.

Really?  Science dominates our consciousness to that extent?  There are points at which I think she realized how much she may have gone overboard about the consequences of the rise of the evolutionary-based taxonomy, and decided to leaven her message with some additional forces that might have contributed to our purported disconnect from nature.  Consider this passage which begins with her central message and then segues into a discussion of how more than taxonomy might be at work:

Maybe it's no coincidence that, as taxonomy’s relationship with the living world began to change in many ways, so did everyone else's.  It wasn't just scientists who were stepping away from luxuriating in the sights, smells, and sounds of the living world.  The rest of us were, too.  The 1960s certainly wasn't an age of spending one's weekends collecting shells or butterflies.  But even beyond the decline of pure natural history pursuits, whose once obvious appeal had become largely mysterious, other factors were conspiring to decrease our chances for interaction with the living world.  The paying work that brought people into regular, intimate contact with nature – small-scale farming, hunting, and fishing – was on the decline, the inefficient individual replaced by much more efficient industrial scale machinery.  (Yoon, p. 207.)

Frankly, I think she has it right at the end of that quotation:  the rate of urbanization and industrialization probably has had much more to do with changes in people’s daily relationship with nature than did any of the musings of cladists.

I also wonder whether the loss of the human umwelt in scientific taxonomy can really explain why human beings might be so unconcerned and accepting, as Yoon sees it, of the decimation of different species.  Wasn't it often so in the past?  Even when taxonomy still largely enshrined the human umwelt, we drove countless species into extinction.  Think of the passenger pigeon, for instance.  Go back still further, to say, 52,000 to 9,000 BCE, well before we had science at all, when we were still thoroughly immersed in our umwelt for our very survival, and what do we find?  Early humans across this span of time were most likely at the center of the extinction of the world’s megafauna.  (See, for example, Hannah Ritchie, Did Humans Cause the Quaternary Megafauna Extinction?, Our World in Data, November 30, 2022.)  We humans seemingly have for a very long time had no compunction about doing away with entire species.  Cladistics doesn't really merit the blame here.

An unscientific sample of one (me) suggests how limited the impact of the cladists and the death of fish have had on our (my) understanding of the natural world.  Earlier this year, I read science writer Lulu Miller’s widely acclaimed book Why Fish Don’t Exist:  A Story of Loss, Love, and the Hidden Order of Life (2020), a book that (deliberately) defies facile categorization, flowing among genres:  memoir (of finding personal and sexual identity), biography (of David Starr Jordon (1851-1931), a renowned ichthyologist and the first president of Stanford University, and a thoroughly despicable individual whose view of static categories within the natural order led him to eugenics), and popular science (of the death of fish).  

Until I read Miller’s book, I was blissfully unaware of the “calamitous” consequences of the rise of cladistics, something that clearly had no impact on me.  Was I previously aware of cladistics?  Yes.  Did my nascent understanding of cladistics somehow wrest me away from my love of natural history and my connections to the living world?  No.  I never felt it threatened my sense of the world around me.  Even more damning, it was Miller’s book itself that alerted me to the demise of fish as a “real” category of organisms.  So much for the impact (at least on me) of the “death” of fish.

Let me expand my unscientific sample of one to a larger, but still unscientific, sample of two by including Lulu Miller herself.  She has written and reported on science for NPR, and currently cohosts NPR’s Radiolab; so, she’s presumably certainly well read and attuned to what is going on in the world of science.  But she writes that her introduction to the cladists and what they did to fish was in fact Yoon’s book published in 2009.  How can that be, if the triumph of the cladists in the 1970s and 1980s left all of us disconnected from nature and uncaring about its fate?  I doubt that she was, and I know I wasn’t.

Nevertheless, despite my grumblings about Naming Nature, it merits a reading.