Thursday, December 29, 2016

Tales Written in Leaves, Part II ~ Reading Insect Damage

Outside I look lived-in
Like the bones in a shrine.
~ Jeff Tweedy in the Wilco song One Sunday Morning (Song for Jane Smiley’s Boyfriend)

[This is the second of a two-part post on leaves.  The first dealt with deciduousness and where I might place the blame for having to spend many Fall hours raking leaves.]

Fossils are time travelers, dancing past those temporal constraints that bind the living.  Connecting past, present, and future, they often carry insights (sometimes profound) into events of deep time which can, perhaps, elucidate what is transpiring today and what may happen in the future.  All of this is contingent on us being smart enough to read and understand their messages.

My current obsession with leaves has exposed me to what I find to be a striking example of how intimate the interplay in fossils among past, present, and future can be.  Case in point is paleontological work on the insect damage appearing on fossil leaf compressions.  The beauty of such compressions is that they record an ancient interaction of then-living organisms, offering an opportunity to explore that once dynamic relationship.  As paleobotanist Peter Wilf has written, "Plant fossils, uniquely in the fossil record, present abundant and diverse information about at least two, and sometimes more (when there is evidence of predation) levels of a food web.”  (Insect-Damaged Fossil Leaves Record Food Web Response to Ancient Climate Change and Extinction, New Phytologist, volume 178, 2008.)

For example, the Paleocene fossil leaf from the Fort Union formation, which appeared in Part I of this post (previously published), exhibits several areas with insect damage.  The full fossil is shown below on the left with one area of damage marked; that same marked area is shown magnified on the right.

There is much to learn from such fossilized traces of past activity.  Consider, for example, the recent study which concluded that not only had animals and plants of the southern latitudes experienced widespread extinctions at the end of the Cretaceous Period (66 million years ago) as did their counterparts in northern latitudes, but that the southern biotas recovered more rapidly.  The basis for these findings?  Insect damage to leaves.

Geosciences doctoral student Michael P. Donovan and his colleagues compared (1) the diversity of insect damage in fossil leaves recovered from sites in North Dakota that straddle the end-Cretaceous, to (2) the diversity of damage on fossil leaves from sites in Patagonia, Argentina, covering a similar time period.  (Rapid Recovery of Patagonian Plant-Insect Associations After the End-Cretaceous Extinction, Nature Ecology & Evolution, Volume 1, 2016.)

To measure insect damage diversity, Donovan et al. identified instances of “damage type” occurring in the fossil leaves using the Guide to Insect (and Other) Damage Types on Compressed Plant Fossils (Conrad C. Labandeira et al., Version 3.0, Spring, 2007 – I refer to this subsequently as the Guide).  The current published version of the Guide identifies 150 distinct damage types (DTs) falling primarily into these categories:  hole feeding, margin feeding, skeletonization, surface feeding, piercing and sucking, oviposition, mining, and galling.  (More on some of these categories later.)  Paleoentomologist Labandeira and his colleagues note that each DT “is defined by a diagnostic suite of characters and is unambiguously separated from the other DTs.”

I will return to the Guide in a bit (it’s really quite a special work), but, first, it’s important to consider a premise upon which Donovan’s analysis rested:  that the diversity of insect damage is positively related to the diversity of the insects inflicting that damage.  This is a great example of a fossil-mediated intersection of past and present.  In assessing the impact of environmental change in the past, paleontologists have used the degree of insect damage diversity found in fossils from specific sites as a proxy for the richness of the diversity of insects that were present at the same time at those same sites.  Using traces of insect activity as a gauge of the mixture of insects active at a site in deep time is a function of necessity.  As Labandeira has noted elsewhere, plant fossils with evidence of insect activity are much more prevalent in the fossil record than insect body parts (Assessing the Fossil Record of Plant-Insect Associations:  Ichnodata Versus Body-Fossil Data, SEPM Special Publication No. 88, 2007).

Were it to be shown that, in reality, the diversity of insect damage types in fossils from particular locations bore little or no relationship to the diversity of insects there, then various findings regarding past impact of climate change on flora and fauna would be called into question.  But, in an instance of research on the past driving research in the present (of benefit to different groups of researchers), botanist Mónica R. Carvalho and her colleagues tested that specific premise by analyzing present-day forests (Insect Leaf-Chewing Damage Tracks Herbivore Richness in Modern and Ancient Forests, PLOS ONE, Volume 9, Issue 5, May, 2014).  As she noted, “Here, for the first time, we test directly for a quantitative relationship between the numbers of leaf-chewing insect species and the DT richness induced by the same sampled insects under observation, among single host-plant species.”

Using cranes in two tropical rain forest sites in Panama, they collected insects from the canopies of dominant angiosperms along with data on external damage types on canopy leaves.  Their findings:  insect species richness and damage type richness are, indeed, very strongly correlated.  “Insect-feeding damage, especially with specialized damage included, is likely to be a robust indicator of relative changes in herbivore diversity and composition in fossil and, of great potential importance, in living forest.”  Ah, things seem to work both ways - a tool used by paleontologists to gauge the impact of climate and other environmental changes in the past might have significant applications for tracking biodiversity changes today with clear implications for the future.

I would note that Carvalho used the Guide to quantify the leaf-chewing damage diversity she found in leaves collected in the rainforest canopies.  Yes, she was testing a paleontological hypothesis and, so, I guess, it made sense to apply the same quantifiable measures, based on the Guide, to contemporary leaves.  Is there a counterpart to the Guide that might be applied to evidence of insect damage found in living or recently fallen leaves?  Turns out there isn’t.  There are works that describe the traces of insect activity that one might find on today’s plants (a good one is discussed below), but the categorization of damage types that is the Guide’s seminal strength, allowing for quantitative analysis, is apparently unique to it.

Similarly, when biologist Jonathan M. Adams and his colleagues sought to assess in today's forests the validity of conclusions from paleontological studies that the diversity of insect damage types in leaves increased as temperatures increased (as measured through various proxies), they used the Guide (Present-Day Testing of a Paleoecological Pattern:  Is There Really a Latitudinal Difference in Leaf-Feeding Insect-Damage Diversity?, Review of Palaeobotany and Palynology, Volume 162, 2010).  As they noted, “The damage type system [as delineated in the Guide] was developed entirely from fossil examples because there is no similarly detailed classification in standard ecological and entomological literature” (emphasis added).  From their research, they concluded that, by and large, the paleontological pattern generally held for contemporary forests, a finding with potential implications for today’s warming world:  “It appears possible that with warming, ecologists, foresters and farmers will observe a greater range of types of insect attacks on plants.”

In a very limited and rather idiosyncratic way, I've done a little of my own marrying of the past (fossils) with the present, as I've explored some of the insect damage done to the leaves that cascaded down around me this past Fall.  It's mostly been just an exercise in finding examples of insect damage.  As I describe below, I've been using a handbook to explore some of the background for traces left by insects and other invertebrates on leaves today,  But, I also wondered how difficult it would be to use the fossil-based Guide to match its DTs to some of the instances of damage I've found, as Carvalho and Adams did.  No, I'm not engaged in any quantitative analysis, the kind of research for which the Guide was developed, nevertheless it seemed an interesting exercise.  Turns out I may have been able, in some limited way, to actually apply its precise descriptions and depictions of the kinds of damage insects did to damage they still do.

Initially, I was drawn to this whole effort by the following lines in a flyer I came upon from a local group that works to protect a nearby creek:
This time of year, on each “imperfect” leaf, we see the signatures left by critters who drank or ate, or who sheltered between the very surfaces of the leaf, or who stashed their unborn against the day.  Innumerable and often unknown, these small critters are each one part of the whole – eating and being eaten, living and dying . . .  (Laura Mol, The Eco-Contemplative Opportunity of Imperfect Leaves, a flyer issued by Friends of Sligo Creek, October 20, 2016.)
At Laura Mol’s suggestion, I began my exploration of insect damage to present-day leaves with Tracks & Sign of Insects and Other Invertebrates:  A Guide to North American Species (2010) by naturalists Charley Eiseman and Noah Charney.  It’s a picture-rich introduction to the broad sweep of traces of insects (and other invertebrates) one might happen upon.  For leaves, in particular, it does a wonderful job of describing and showing myriad, often horrifying, modes of chewing, puncturing, egg laying, sucking, infesting, and otherwise abusing leaves.  I have to keep reminding myself that insects are in pursuit of their own good cause, the propagation of their species.

The damage insects do may be restricted primarily to the interior of the leaf (endophytic damage) or may involve all layers of the leaf.  From a number of leaves that I collected during the downpour of leaves of several weeks past, I found some nice examples of both kinds of leaf damage and show some of them below.  Most of these involve oak leaves because those are the trees that are most at hand.  My discussion of the possible origins of these different examples of insect damage is based largely on the Tracks & Sign handbook.  When I think I might have found a DT in the Guide that applies to the example in question, I provide the image of a fossil leaf compression from the Guide showing that DT.  (In a personal communication, Dr. Labandeira indicated that the Guide is in the public domain.)

I was particularly pleased to come upon a leaf from a Tulip tree (Liriodendron tulipifera) featuring the circuitous path tunneled out by a leaf miner.  This is the only example below that doesn't come from an oak.  This kind of tree is often called a Tulip Poplar around here, but it’s not a close relative of true Poplars.

I find leaf mining particularly interesting, so will indulge myself and consider it somewhat at length.  In leaf mining, a principal example of interior damage, insect larvae spend their time until maturity sheltered between two epidermal layers, eating the tissue they find there.  These leaf miners are typically the larvae of moths and flies.  Identification is aided immeasurably by that fact that, in many cases, different taxa of leaf miners create distinctive tunnels and specialize in particular kinds of trees.  Some mines remain narrow throughout their course, others start linear and end in blotches (broad areas in which the tissue is consumed), still others create mostly blotchy mines, sometimes with digit-like extensions.  Often fecal pellets line some portions of these mines.  Overall, the coupling of mine patterns and the host plant can be diagnostic of the insect behind the damage.

A portion of the mine in the Tulip tree leaf is shown below.  Given the specific tree host and the linear nature of the mine, this might be the work of a larva of the moth Phyllocnistis liriodendronella.

I would classify this leaf mining as the Guide’s DT43; the brief version of the Guide’s description reads:  “Short, serpentine, with linear margin; solid frass; expanding width.”  It should be remembered that any of these descriptions applies to the appearance of a DT in a fossil leaf compression.  (Frass is insect larvae excrement.)  DT43 is shown below.

Galls are another example of what is endophytic damage despite sometimes being very visible on the leaf surface.  Leaf galls are generated when leaves react to various kinds of foreign organisms including insect eggs.  Most apparently are prompted by mites and insects, particularly gall wasps or cynipids.  Here is a small section of a Pin Oak leaf (Quercus palustris) with several prominent galls.

I will hazard a guess that this is an example of DT80 (shown below), described in the Guide as follows:  “Small, hemispherical; thoroughly carbonized; diameters ~ 0.1 – 1.0 mm; 1˚ and 2˚ veins avoided.”  Are the galls in the Pin Oak leaf above avoiding those veins?

I’m not certain whether skeletonizing damage should be considered endophytic since there are various definitions of what constitutes the phenomenon.  In the one I've followed here, skeletonization need not go through all of the leaf layers.  Some insects or insect larvae skeletonize a leaf by consuming one side, leaving the vein network and the outermost layer of the leaf intact.  As a result, the skeletonized portions of such leaves, covered with the thin remaining layer, can be stunningly translucent when seen in just the right light or under magnification.

I was quite please with the pictures below which show a small skeletonized section of a leaf from a Northern Red Oak (Quercus rubra).  Each image is magnified 10 times:  the one on the left shows a portion of the skeletonized upper surface of the leaf – the mostly still complete outermost layer is evident; the one on the right is roughly this same area viewed from the underside, the veins stand out in stark relief, not covered at all and seemingly undamaged.  Clearly, the skeletonizing organism did its thing on the underside.

I’m uncertain about the DT applicable to this damage, but it may be DT16 (shown below):  “Interveinal tissue removed; reaction rim poorly developed.”  (Reaction rim is, I think, the margin around the damage and reflective of how vigorously the plant responded to the damage.)

Insects may puncture holes in leaves for many different reasons and in myriad configurations.  That the pattern of holes in this White Oak leaf (Quercus alba) is roughly circular may be a good clue as to the culprit, but neither of my references seem to be of much help.  [Later edit:  I should clarify that both sources provide many examples of insect damage involving holes, just no examples with the a pattern similar to that shown below.]

I will close on a somewhat ironic note.  Though I think I’ve matched some of the present-day examples of insect damage to specific DTs in the Guide, I’m stumped by the damage highlighted in the fossil leaf at the beginning of this essay.  Which DT is it?

Saturday, December 10, 2016

Tales Written in Leaves, Part I ~ Blaming the Bolide

In which the blogger confirms, yet again, the dangers of assuming he knows something.
The process has nearly run its course, though oaks and beeches are holding on,  During November and very early December in this area of the northeastern U.S., deciduous trees let go of their leaves in numbers beyond imagination (well, my imagination, at least).  Given that such trees dominate many forests here, it’s not surprising that we were blanketed in leaves.  Metallic growls disturbed daylight hours as folks with leaf blowers tried to corral the fallen leaves, saving the users’ backs while sacrificing their hearing.  Being old school, I chose to sacrifice my back.

While creating my own piles of leaves, dragging a dog through the mounds of leaves that decorated curbsides, or traipsing through nearby woods, I puzzled over this question:  Why am I surrounded by deciduous trees?

A couple of weeks ago, in an instance of serendipity, as I sorted through a stack of recent Natural History magazines, I happened upon a brief review from 2014 of a research article apparently on just that question.  Science writer Ashley Braun posited that this research showed that the impact of the extinction event at the end of the Cretaceous period selected for deciduous plants with their faster growth and disposable leaves.  (Reading Tree Leaves, Natural History, November 2014.)

I wondered whether it was fair to blame the seemingly never-ending cascade of leaves here principally on the Chicxulub bolide that burned through the atmosphere about 65 million years ago and smashed into the shoreline of the Yucatan.  (For many of the writers I’m currently reading, bolide seems to be the term of art for this extraterrestrial object, be it asteroid, comet, what have you.)  The atmospheric consequences of this impact (including an impact winter) are widely believed to have brought the Cretaceous period to an end, causing the extinction of many, many groups of terrestrial and marine organisms, including non-avian dinosaurs.  In North America, over half of all plant species were extinguished.  I was suspicious of this assignment of responsibility, believing, as I do, that the workings of natural history are, more often than not, complex tales of myriad interplaying factors.  Blaming the bolide seemed too simple.

Cretaceous flora included gymnosperms (producers of “naked seeds,” including conifers) which, depending upon whom you read, either were dominant throughout this period or had already been shouldered aside before the bolide impact by the recently appearing angiosperms (flowering plants producing “seeds within a vessel,” including sycamores).  It's mostly (though not exclusively) angiosperms that are deciduous and so the sources today of these myriad throw-away leaves.  And, it should be noted, many angiosperms are also evergreen.

In the article Braun described, Plant Ecological Strategies Shift Across the Cretaceous-Paleogene Boundary (PLoS Biology, Volume 12, Issue 9, September 2014), ecologist Benjamin Blonder and his colleagues focused on fossil angiosperm leaves from two formations in North Dakota – Hell Creek (Upper Cretaceous period) and Fort Union (Lower Paleocene epoch).  By doing so, Blonder keyed in on a slightly more than 2-million-year period that straddles the End Cretaceous event.

To get a very general sense of the kinds of fossils he and his colleagues worked with, I have included a few pictures of material from both of those formations.  The first pictures below show leaves that are part of a slab of matrix from the Hell Creek Formation that is currently on display in the Last American Dinosaurs exhibit at the Smithsonian’s National Museum of Natural History.

The next image shows a single leaf which was found in an outcropping of the Fort Union Formation in Montana.  It comes from my fossil collection.

At the outset of his article, Blonder noted that he was generating quantitative evidence relevant to a qualitative analysis from 1987 by paleobotantist Jack A. Wolfe about the appearance of the deciduous trait in plants across the boundary at the end of the Cretaceous.  It’s helpful to see what Wolfe outlined nearly three decades earlier (Late Cretaceous-Cenozoic History of Deciduousness and the Terminal Cretaceous Event, Paleobiology, Volume 13, Number 3, 1987).  Broad-leaved deciduous plants, Wolfe posited, evolved the deciduous trait to cope with climates that included “periods unfavorable to growth.”  It made evolutionary sense in those situations to speed up the production of leaves, disposable ones at that, emerging quickly to capture sunlight and dropping away before needing to be protected from freezing temperatures.

The global climate from the Late Cretaceous through the Eocene was, Wolfe described it, “generally warm and equable,” a climate that should not have favored deciduous plants.  Not unexpectedly, in the Late Cretaceous, “broad-leaved deciduous plants were of low diversity,” but a change in the composition of the flora marked the epochs (Paleocene and Eocene) immediately following the Cretaceous.  By the Paleocene, the Northern Hemisphere featured a “high diversity of broad-leaved deciduous plants . . . .”  Something or some things, he concluded had selected for the deciduous habit in Northern Hemisphere vegetation between the Cretaceous and Paleocene.  Wolfe suggested the “change resulted from a brief low-temperature excursion, probably an ‘impact winter.’”

Enter Blonder.  He analyzed changes in two key leaf variables during this narrow time period – leaf mass per area and minor vein density.  The first gauges plants’ investment in leaf construction (mass per area); the second relates to the transportation of water and carbon (vein density).  Variations in these investments fall across a spectrum from evergreen, “slow-return” leaves that are long lived with significant carbon tissue (relatively high mass per area and low vein density) to deciduous, “high-return" leaves that are shorter lived with less carbon tissue (relatively low mass per area and high vein density).

With results supporting Wolfe's analysis, Blonder found that, across the end-of-the-Cretaceous boundary, leaf mass per area fell while minor vein density rose.  The decline in leaf mass per area apparently resulted from the extinction of species abundant during the Cretaceous with high leaf mass per area; the rise in vein density across the boundary was affected primarily by the loss of species with low vein density.  In other words, overall changes were in the direction of increasing deciduousness.  In the impact and immediate post-impact period, fast growing plants were favored as deciduous species were selected for while evergreen species were selected against.  Rapid growth with disposable leaves was apparently the ticket to deal with this unstable environment.  Blonder has observed,
This tells us that the extinction was not random, and the way in which a plant acquires resources predicts how it can respond to a major disturbance. And potentially this also tells us why we find that modern forests are generally deciduous and not evergreen.  (As quoted by Daniel Stolte in Meteorite That Doomed Dinosaurs Remade Forests, University of Arizona, UA News, September 16, 2014.)
So, I guess that's where I end up in this post, where I started.  Though none of this suggests how challenging I found this whole exercise.  I became mired in the debate within the scientific community over whether angiosperms dominated Cretaceous flora or, instead, were widespread but marginalized.  Compounding my frustration was that it took me  much too long to realize that I was essentially equating angiosperm with deciduousness which made the conflicting positions on angiosperm dominance all the more confusing.

In closing, I hesitate to note that there’s some dissent (of course there is) from the position that angiosperms hold sway today.  See, for example, Timothy J. Brodribb et al., Elegance Versus Speed:  Examining the Competition Between Conifer and Angiosperm Trees (International Journal of Plant Sciences, Volume 173, Number 6, July/August 2012).  But I won't get into it.

[In a second post, tentatively titled Tales Written in Leaves, Part II ~ The Damage Done, I will turn to the stories that can be read on leaves about the travails of the summer just past, or of summers gone by millions of years ago.]

Sunday, November 6, 2016

A Tribute to Cartoonist Richard Thompson ~ Humor, Insight, and Side Glances to Natural History

Over the past couple of weeks, I’ve sought refuge from the world in The Complete Cul de Sac, volumes one and two (2013, Kindle edition; of note, being able to view in color those strips that ran in color is important).  It’s a compilation of the comic strips that first appeared in the Washington Post in 2004 and later went into nationwide syndication for five years, last appearing in September, 2012.  These two volumes feature a self-deprecating commentary by the cartoonist, Richard Thompson.

(This thumbnail image is from the Amazon website.)

From its debut to its farewell, Cul de Sac was a favorite of mine.  Thompson brought a discerning eye to the joys, anxieties, and confusions of children who are, of course, relatively new to a world upon which they are trying, and often failing, to impose their own sense of reality.  With warmth, humor, and insight, buttressed by delightful art, Thompson created a remarkably real family centering his attention on four-year-old Alice Otterloop, an outspoken, rather egomaniacal, erratic shooting star of a child, and her brother, the world-wary (and –weary), eight-year-old Petey, whose idea of a perfect day is one spent alone, lying on his bed, staring at a single page of a Little Neuro comic book.  (A bit of trivia of which I'm fond:  The Otterloops, who live in the suburbs of Washington, D.C., have a surname that is a play on the “outer loop” of the Beltway, the highway that encircles the city.)

I was away most of the summer and my contact with newspapers was a bit sporadic.  So, just a few days ago, in the midst of receiving solace from Cul de Sac, it was a brutal shock to learn that, this past July, Thompson died at age 58.  For several years, he had shown grace and courage as he endured an awful battle with Parkinson’s, a battle that wreaked havoc on his artistic career, forcing the end of his strip, and one that ultimately took his life.  As down as this news brought me, the achievement that is Cul de Sac remains, still offering laughter, wisdom, and, most of all, a curious sort of comfort.

For me, the best settings for the strip are in the Blisshaven Academy, A Preschool (so reads the sign outside the building, a former body shop) or in the school’s van, with Alice and her classmates –Marcus, Nara, Beni, Kevin (he of the “bucket head”), and, most certainly, the inimitable Dill (whose comments, at times strange and slightly disturbing, and other times wonderfully trenchant, can provide a counter-punchline in the final panel of a strip).

Thompson knew and, perhaps, understood, four-year-olds.  There’s no better indication of that than the strip of October 14, 2007 (see it on GoComics) in which the banjo-playing Timmy Fretwork comes to school to play and sing.  After announcing that his first song will involve a farmer and his dog Bingo, he makes the fateful and seeming inevitable mistake that adults succumb to with children at that age – responding to a raised hand and opening the floor to questions.

Nara:  I have a dog.

Miss Bliss (headmistress of the school):  Nara!  That’s not a question.

At which point, the chain reaction cannot be contained and the class explodes with comments.

Various members of the class:  I have a dog.  I have a dog, too!  I have two cats!  My dog runs fast.  My cat sleeps on my bed.  One time I saw my dog eat snow.

And then . . .

Dill:  One time I put a snow-globe in the microwave and pushed “Hot Dog”

In the final panel, the entire class is in the time-out corner.  And, yes, there’s one final comment.

Nara:  Every time that woman tries to cram culture down our throats, this happens.

In the Complete Cul de Sac, Thompson observed, of this particular strip, “I’m told this is a frighteningly accurate portrayal of classroom behavior, which worries me as it’s just my normal thought process.”  If another piece of dispositive evidence is needed that Thompson knew young children, check out the strip in which the preschoolers play Charades (November 1, 2009).

Oh, Petey’s bedroom is also one of my favorite venues.

This time through Cul de Sac, I was impressed at how the strip is, surprisingly often, a paean to natural history, at least, as it’s seen through young children’s eyes.  Here are just a few instances.  In various strips, we have a child:

  • observing that wild birds flying loose in grocery stores develop regional characteristics depending upon the aisle they live in (e.g., the cereal aisle denizens sport “gaudy, unnaturally hued plumage”), a situation summed up by Petey’s observation:  “Nature’s most interesting when it’s indoors.” (January 31, 2010)
  • spouting parodies of those hyped nature shows on TV – Dill explains that he knows how a “new old toy” came to be in the Blisshaven playground because “I saw it on a TV nature show called ‘Silly Migration:  Feral Toys of the North American Playgrounds.’” (October 9, 2011)
  • misconstruing the meaning of words such as “carnivores” - Alice:  “Yeah!  Carnivores are the cute ones, right?” (December 18, 2009)
  • lamenting animals gone extinct - when Alice thinks she’s met Mother Nature, Dill says, “Tell her to bring back those giant ground sloths.  I like those!” (April 25, 2010)

My favorite of all of the Cul de Sac strips ran on May 20, 2007, before the comic went into syndication (no link, sorry).  Its setting is the Blisshaven van; the class is on a field trip.  Miss Bliss tells them they’re on the way to the National Museum of Natural History.  Seeking some sort of recognition from the children about their destination, she blurts out a string of questions regarding the museum:  “Where the big elephant is?  And the Hope Diamond?  The insect zoo?”  Silence.  No reaction from the children.

Miss Bliss:  The dinosaurs?

Class:  AAH!

Then we spiral into the world of four-year-olds where they are amazingly articulate and informed about those things which interest them, and not so much about the rest of the stuff out there.

Kevin:  What do you think of recent theories that Tyrannosaurus rex was actually a scavenger and not a predator?

Beni (it’s possible that the speech bubble might be pointing to Dill):  What revisionist nonsense!

More informed debate from the preschoolers is interrupted by Miss Bliss.

Miss Bliss:  We aren’t looking at dinosaurs on this field trip.  We’re going to the Hall of Mammals.

Various class members:  What are “Mammals”?  Rocks, I think.  Must be something new.

Thank you, Richard Thompson.

Sunday, October 30, 2016

Micromollusks – Little Means A Lot

The key to taking the measure of biodiversity lies in a downward adjustment of scale.  The smaller the organism, the broader the frontier and the deeper the unmapped terrain.
                                   ~ Edward O. Wilson, Naturalist, 1994, p. 363-364.
“Whatever it is, it’s very, very little.”
                                  ~ line spoken by one of three jowly and mustachioed men crowded around a microscope in a cartoon by James Stevenson
Species diversity is a crucial gauge of the health of an ecosystem.  Botanist and ecologist Ruth Patrick, working with diatoms in river systems, showed that the health of those water environments can be measured by the diversity of the living communities they host (an indicator known as the Patrick Principle).  (See, Patrick Principle(s), a post on this blog.)  Comparing species diversity over time, particularly when ancient environments are involved, is important for understanding the effects of environmental change (most obviously something like, say, the end-Permian mass extinction).  But it’s a profound challenge.  How does one know whether the floral or faunal diversity for any time period and any location has been accurately measured?  It’s particularly a problem given how limited our knowledge is of the smallest organisms living today, much less those tiny entities that lived in the past.  This issue came to the fore recently for me as I sifted through a sample of matrix from a Pliocene formation.

A year ago, while on vacation at Bradenton Beach, Florida, a friend came upon massive grey mounds of shelly sand stretching across one end of a parking lot next to a local beach.  He was not the first to recognize that this material, dug from a nearby quarry, was a treasure trove of Pliocene Epoch fossil mollusk shells.  Climbing these piles, he began collecting fossil shells with purpose, knowing there was a death sentence hanging over this scene.  Yes, all too soon, this beach parking lot had been repaved with this three-million-year-old mixture of sand and fossils.

The fossil shells he saved from destruction are breathtaking in their diversity and their state of preservation.  Here are just a very few of the specimens he rescued.

I think this picture shows, from left to right, the following species:

  • Cancellaria conradiana (a Nutmeg Shell)
  • Terebraspira sp. (a Tulip Shell, though, for the life of me, I cannot figure out its species)
  • Fasciolaria apicina (a Tulip Shell)
  • Strombus floridanus (a Conch).
Among the resources I consulted were the gastropod section of Florida Museum of Natural History’s Invertebrate Paleontology Image Galleries; Roger W. Portell, et al., Southeastern Geological Society Field Trip Guidebook 56:  SMR Aggregates, Inc., Sarasota, Florida, May 19, 2012; Axel A. Olsson and Anne Harbison, Pliocene Mollusca of Southern Florida, 1979 reprint of the 1953 edition; and Carol Peterson and Bernie Peterson, Southern Florida’s Fossil Seashells, 2008 (a useful, self-published effort by two amateurs).

Knowing of my peculiar interest in microfossils (specifically, the shells from foraminifera and ostracodes), my friend collected the matrix he extracted from his finds and passed it on to me.  His container of choice for this offering was a coffee can whose delightfully rusting exterior belied the beauty of the myriad fossils hidden inside.  After working on this rich mixture for a bit, I find that I’m spending surprisingly little time collecting and identifying my usual suspects.  Instead, I have been diverted (in both senses of the word – redirected and entertained) by the many, many micromollusks that leaven this matrix.

A definition is in order.  Though somewhat widely used, the term micromollusk (or micromollusc in all of the English-speaking world outside of the U.S., which also uses mollusc instead of mollusk) is new to me and apparently not some codified category of mollusk.  In most instances, this term appears to be applied to any mollusk whose adult form does not exceed 5 mm in size.  The 2007 symposium titled Micromolluscs:  Methodological Challenges – Exciting Results used the definition of “molluscs no larger than 5 mm.”  Authors in this symposium also employed the label microgastropod to describe any adult gastropod up to 5 mm in size.  This definition is highly arbitrary and I find no particular reason for the 5 mm threshold dividing micro and macro.  Yet, given its usage elsewhere, it’s what I will employ in this post.  In fact, it’s certainly more useful for analysis than my preferred definition of a microfossil and, by extension, a micromollusk or a microgastropod:  “a specimen whose study requires magnification.”

Given that the matrix in the coffee can had, in effect, been screened already (component pieces had to be small enough to fit inside larger fossil shells), any specimens that came to me had to be relatively small, most likely falling below the 5 mm threshold.  I did some further screening, using a sieve with 1 mm square mesh which allows me to focus on still smaller specimens.  But, as is obvious from the several specimens pictured below, some that exceed 1 mm in a dimension are able to slip through.

Yes, there are foraminifera and ostracodes here in fairly large numbers, but what is striking is the abundance of micromollusks, principally microgastropods.  It’s a phenomenon I have not encountered to such an extent with any other matrix I’ve explored for my usual tiny quarries.

The purported source of the material probably explains why I am awash in these minute specimens.  The piles on the Bradenton Beach parking lot likely came from the quarries of SMR Aggregates, Inc., which mines material for use in the construction of roads, construction of buildings’ foundations, landscaping, and making of concrete.  If this is the actual source of this material, then its geological origins are the prized Pinecrest Beds of the Tamiami Formation.

The Pinecrest Beds are considered to be among “some of the most species rich and densely packed fossil horizons known in the world.”  (Portell, SMR Aggregates, p. 7.)  I describe the Pinecrest Beds as being from the Upper Pliocene Epoch (this epoch ended about 2.58 million-years-ago) based on an analysis by paleontologist Lauck Ward (Diagnostic Mollusks From the APAC Pit, Sarasota, Florida, Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Special Publication #36, Florida Geological Survey, 1992, Figure 1.)  In contrast, Portell, et al. posited that these beds straddled the Pliocene/Pleistocene boundary (SMR Aggregates, p. 5).  There is agreement that much of the Pinecrest was deposited in a relatively shallow (perhaps less than 100 feet deep), tropical to temperate marine environment.  Obviously, it was a very fecund environment with apparently high levels of species diversity.

Here is one slide with a selection of microgastropods from this material.  There are 61 specimens pictured here.  (There’s certainly something to be said about microfossils – storage is not the problem it is with every other fossil I collect.)

And here are three examples of these microgastropods:

Turbonilla sp.

For better or worse (possibly for the worse), the identification of this first specimen is based principally on Pliocene Molluscs From the Yorktown and Chowan River Formations in Virginia, written by geologist Lyle D. Campbell (Virginia Division of Mineral Resources, Publication 127, 1993, p. 103-104, image 520 on Plate 42).  [The discussion of this species has been edited after I initially uploaded this post.]  In fact, based on Campbell, I originally identified this as Turbonilla (Chemnitzia) beta, a species he asserted was new.  I don’t see the name being used later, and probably only the genus name (without the subgenus designation) is accurate.  I should note that Campbell did extensive work on mollusks, amassing a large and scientifically important collection (see below).  But, this particular volume of his has been taken to task.  Paleontologists Lauck W. Ward and Norman L. Gilinksy criticized it severely for myriad faults, ranging from “inadequate descriptions” to the “lumping together of clearly different taxa.”  And, from my perspective (an amateur looking for help in identifications), one of their most damning comments was that “the poor quality of the original specimen photographs makes clear identifications difficult.”  (Biostratigraphic Analysis of the Chowan River Formation (Upper Pliocene) and Adjoining Units, the Moore House Member of the Yorktown Formation (Upper Pliocene) and the James City Formation (Lower Pleistocene), Virginia Museum of Natural History, Memoir Number 3, Part A, 1993, p. 8).

Teinostoma sp.

For this second shell, I find several morphologically similar specimens identified as Teinostoma in Campbell (p. 60-61, and specimens 266 through 274 on Plate 27).  Also, several similar specimens identified as in the Teinostoma genus are pictured in Micromollusks of the Lower Pinecrest Beds, Upper Tamiami Formation, Sarasota County, Florida which appears on the Jaxshells (Jacksonville Shells) website.  The diversity of species within this genus thwarts me at present.

Ringicula guppyi

I am fairly confident about the final one, Ringicula guppyi, based on several sources, including the Florida Museum of Natural History, gastropod section of its Invertebrate Paleontology Image Galleries.  The photograph of the specimen with UF Catalog Number of 137290 is quite persuasive.

My (belated) discovery of micromollusks, and of microgastropods in particular, has reinforced my appreciation of the epigraph from biologist E.O. Wilson that begins this post.  As Wilson went on to observe, “Most of Earth’s largest species – mammals, birds, and trees – have been seen and documented.”  (Naturalist, p. 364.)  Size matters when it comes to our natural impulse to collect, identify, and categorize, if only because the big stuff is what’s easiest to find.  It’s the little that gets overlooked and ignored.

Seashells are an excellent case in point.  When malacologist Philippe Bouchet and his colleagues undertook to make a complete inventory of the diversity of extant mollusk species at a site in New Caledonia, they felt compelled to explain why such an effort was necessary.  They noted that, despite the fact that mollusks are regularly included in analyses of marine biodiversity, and that the long standing interest in seashells by malacologist and collectors has produced a great deal of information about species diversity, there is a serious gap.
[M]uch of the literature focuses on macromolluscs (‘seashells’) that can be collected by picking in the field, and tends to ignore or grossly underestimate the smaller species.  This is probably because micromolluscs require specific collecting/sorting attention and have a reputation to present formidable taxonomic difficulties.
(Philippe Bouchet et al., Assessing the Magnitude of Species Richness in Tropical Marine Environments:  Exceptionally High Numbers of Molluscs at a New Caledonia Site, Biological Journal of the Linnean Society, Volume 75, 2002, p. 422.)
Bouchet et al. showed how important a component the smallest mollusk species is of a fauna.  They found that, of the 2,581 mollusk species found at their site, fully a third (33.59%) were 4.1 mm in size or smaller (no 5 mm threshold used here).  It strikes me that, if work on living mollusks, such as that by Bouchet and colleagues, still needs to be done, the data on micromollusks in the fossil record must present much greater challenges to any consideration of changes in biodiversity reaching back into deep time.

The micromollusks of the Pliocene Pinecrest Beds have played a central role in analyses of changes in marine biodiversity in the western Atlantic coastal plain.  Before the early 1990s, it was generally understood that molluscan biodiversity in the western Atlantic tropical and subtropical environments had reached a peak across the Miocene and Pliocene Epoch, and then suffered serious losses, leading to a presently impoverished molluscan fauna.  In essence, there are fewer species living today than there were in the Pliocene.

In 1993, paleontologist Warren D. Allmon and colleagues challenged that assessment with an article in Science titled Diversity of Atlantic Coastal Plain Mollusks Since the Pliocene (Vol. 260, June 11, 1993).  For their reading of diversity in the Pliocene, they relied largely on gastropod fossils from the Pinecrest Beds.  They identified 460 species of gastropod larger than 5 mm and another 40 smaller than that from that geological location.  But, recognizing there is a size bias in the fossil record, they turned to data on all extant shallow water gastropods in Florida which showed that approximately 22% of those extant gastropods were 5 mm or smaller.  They assumed that this ratio was also applicable in the Pliocene and, so, estimated that there was a total of approximately 590 gastropod species living in the Pliocene in the area where the Pinecrest Beds were laid down.  Thus, of this total, an estimated 130 were microgastropods.

Armed with these estimates and data on the diversity of extant gastropods, Allmon et al. concluded that there had not been a loss of molluscan species diversity over this time period.  Although they found that fully 70% of the gastropod species in the Pinecrest are presently extinct, this loss has been made up by the appearance of many new species – rates of extinction seemed to have been balanced by rates of origination.  They acknowledged that more species might well turn up with further work in the Pinecrest, but suggested that any increase in Pliocene numbers would be balanced by the identification of new extant species.  The report on Pinecrest micromollusks posted on the Jaxshells (Jacksonville Shells) website (cited above) suggests that discovery of new micromollusk species continues apace, as does identification of new extant species (thought it's agnostic about whether they are in balance).

Micromollusks, microgastropods aren’t just curiosities.  They are integral parts of their environment, past and present, and, as such, have much to tell us.  So much so that, in 2015, the National Science Foundation awarded a grant to the University of Florida so that two collections of the Florida Museum of Natural History could be saved and permanently housed.  One of them, a collection of mollusks collected by Lyle Campbell, is described as “an exceptional, nationally unique inventory of fossil micro-mollusks.”  Under this grant, these collections will become research and teaching tools.  Products from this grant include two identification guides and 1,500 images – all to be made available online.  Frankly, I cannot wait.

And, if research applications aren’t sufficient motivation to get excited about micromollusks, I also embrace the sentiment attributed to Immanuel Kant:
Look closely.  The beautiful may be small.

Thursday, September 29, 2016

Transitions ~ Fossil Stem Turtles and Antique Theater Playbills

In which the blogger persists in his mad quest to find connections between two disparate subjects, come hell or high water.
I began my summer studying literature on the evolution of the turtle shell and ended it engrossed in a wonderful doctoral thesis on British theater playbills.  Unexpectedly, I found that these two topics had something important in common.  Both speak to the challenge of identifying and understanding transitions.  Recognizing where, when, why, and how transitions occur, say between one species and a daughter species, or from one function for a specific body part to another function, is a core issue in paleontology, one often particularly difficult to determine from, or map in, the fossil record.  As to British theater playbills, the doctoral thesis I read grappled with the transition of playbill to play program, offering, in the process, a perspective on a core issue for understanding transitions – it’s critically a matter of definitions.  [Note:  This discussion below of the turtle shell draws heavily on an article I wrote for a fossil club newsletter.]


In an article published in July this year, paleontologist Tyler R. Lyson and his colleagues provocatively hypothesized that the turtle’s shell got its start in the Permian (some 260 million years ago) in the lizard-like reptile, Eunotosaurus africanus.  (Fossorial Origin of the Turtle Shell, Current Biology, July 14, 2016)  To understand the nuances of Lyson’ hypothesis, it’s helpful to first consider the shell in extant turtles.  The shell consists of two principal elements:  the arched carapace on the dorsal side of the animal, and the flat shield-like plastron on its ventral side.  Pictured below is the skeleton of a yellow-bellied slider (Trachemys scripta scripta) on display at the Smithsonian’s National Museum of Natural History.  A section of the carapace has been cut and hinged to expose the plastron.  The horny scutes, that, in life, adhere to the bones that make up the carapace and plastron, have been wired to the skeleton.  (The signage at the Museum is silent on whether this is an actual skeleton or a cast.)

According to Lyson, Eunotosaurus, which lived in the drought-stricken Karoo Basin of South Africa, shows evidence of the earliest known steps toward fashioning at least one aspect of a turtle shell – the carapace.  The most complete Eunotosaurus fossils have broadened dorsal ribs and a reduced number of vertebrae and ribs (the purported incipient carapace), along with powerful shoulders, forelimbs, and large claws.  The incipient carapace shell, Lyson posits, helped the animal with a fossorial (e.g., burrowing) lifestyle, enabling it to escape the rigors of its terrestrial environment which was an ancient floodplain where any bodies of water were certainly short-lived.  The price it paid by adding rigidity to its dorsal side (thereby, sacrificing easier and more efficient breathing and locomotion) was outweighed by the advantages of burrowing aided by this incipient carapace.  Lyson doesn’t deny the obvious current role of the shell in protecting the animal, but asserts that defense is an “exaptation,” a function that the shell acquired later.

Overall, Lyson’s is a striking hypothesis, challenging the widely held belief that the turtle shell evolved as a defensive structure, and that its initial stages occurred in an aquatic environment.  The entire issue is awash in questions of transitions, of where to draw lines.  Most critically, Lyson’s hypothesis rests on an identification of so-called “stem turtles,” those species that we consider antecedents to “crown turtles,” as well as his characterization of the environments within which the known stem turtles lived.  A stem turtle shares some, but not all, of the traits we deem necessary for a species to be considered a true or crown turtle.

Is Eunotosaurus actually a stem turtle as Lyson would have it?  The challenge is determining where the transition from non-turtle reptile to stem turtle occurs, and there are consequences for how we do that.  If Eunotosaurus is the earliest known stem turtle, then, not only might the fossorial hypothesis about the shell’s original purpose be correct, but so would terrestrial and Permian beginnings for turtles.

But, if it isn’t a stem turtle, then there are younger candidates among known fossils which appear to tell a somewhat different story.  Among these are the following two.

1)  Pappochelys rosinea, dating from the middle Triassic (about 240 million years ago), had, in addition to what appears to be an incipient carapace, paired gastralia (bones that some reptiles have in their abdominal walls) and some ossification and fusion in the ventral region which, while not constituting a plastron, seem headed in that direction.  The animal lived in a lacustrine (i.e., having lakes) environment.  Paleontologists Rainer Schoch and Hans-Dieter Sues, who first described Pappochelys, conclude that it probably “lived along the lakeshore or frequently entered the lake,” and that its features were “consistent with aquatic or semi-aquatic habits”  (A Middle Triassic Stem-Turtle and the Evolution of the Turtle Body Plan, Nature, Volume 523, July 30, 2015, p. 587.)

2) Odontochelys semitestacea, which lived about 220 million years ago in the Triassic, was, until recently, very widely accepted as the earliest known stem turtle.  Although it had an only partially evolved carapace with some broadening of the dorsal ribs, its plastron was fully developed.  (Chun Li, et al., An Ancestral Turtle from the Late Triassic of Southwestern China, Nature, Volume 456, November 27, 2008.)  Fossils of this animal have been found in what was, in the Triassic, a near-shore marine environment, which lead Li et al. to conclude that the characteristics of Odontochelys are “indicative of primarily aquatic habits and of a possible aquatic origin of turtles.”  (p. 500.)

I am struck by another question that poses somewhat of a transition issue.  How should we characterize a lacustrine environment?  Lyson looked at the available candidates for stem turtles and concluded that Odontochelys was the outlier because of the fairly clear aquatic nature of its place of origin.  He argued that the rest, including those coming from lacustrine environments such as Pappochelys and the stem turtle with the earliest complete turtle shell in the fossil record, Proganochelys quenstedti (Triassic, about 215 million years ago), should be considered terrestrial in origin.  I do wonder whether environments which feature lakes are to be so easily deemed terrestrial.  Isn’t it possible that the species found in such environments lived in the lake waters, or moved between lake and land in their quotidian activities?

Also, I see an argument to be made that the morphological changes that paleontologists see as leading to carapaces and plastrons might have had two concurrent functions – aid for burrowing and for defense.  An animal that spent even just part of its time in lake waters might benefit from, at least, the beginnings of a plastron to deal with predators coming from below, and might also do some burrowing when on land, aided by an incipient carapace.  Further, did these ancient species hibernate, a burrowing activity that modern turtles living on land and in water may engage in?

There might well have been other functions of the various features of the turtle shell.  For instance, some have suggested that the plastron served as ballast for aquatic species, helping them stay properly oriented.

Odontochelys offers up yet another transition conundrum.  Why is Odontochelys’s plastron the earliest completed element of the turtle shell that we know from the fossil record?  It's already been suggested that a water dwelling species might benefit from the protection it provided against predators coming from below or for its possible function as ballast.  But, there are alternative hypotheses about where in the development of the turtle Odontochelys should be placed.  Paleontologists Robert R. Reisz and Jason Head, for example, suggest that Odontochelys was part of a radiation of turtles from land to sea and that the partial carapace was the remnant of what had been, in some older species, a complete carapace.  (Turtle Origins Out to Sea, Nature, Volume 456, November 27, 2008.)  In other words, this species was in the process of losing the carapace while retaining the full plastron which was functionally useful in a marine environment.  Further, this suggests there may be fossils from terrestrial stem turtles older than Odontochelys with complete shells waiting to be discovered, and that evolution of the plastron and carapace occurred in an essentially terrestrial environment, possibly in support of burrowing.

I have to assume that finding more fossils that further illuminate the evolutionary process that led to today’s turtle will also fuel continuing debates about whether some particular new fossil find represents a stem turtle or not, and what flows from that.


Late this summer, when I acquired two antique British playbills, I found myself, once again, exploring transitions.

Some context for this acquisition is probably in order.  When I was a college student, I worked for two summers as a page at the Folger Shakespeare Library in Washington, D.C., retrieving items from the closed stacks and vaults of the library for researchers.  An ongoing project of mine was to assign dates to myriad 18th century British playbills, many of which omitted the year of the performance.  Memories of my time spent with those thin, often yellowed sheets of paper with their relatively crude printing flooded back when, in August, I was wandering through an antique store and came upon two very early 19th century British playbills in frames.  Their allure was irresistible; they now hang over my desk.  (They are roughly 7 1/2 inches wide and 12 1/2 inches high.)

British playbills, it turns out, evolved over several centuries.  The first extant bill for an indoor performance at a theater performance is dated 1687; bills for outdoor performances predate that.  Over time, their roles changed and expanded, sometimes also serving as play programs, and ultimately being superseded by programs.  David Robert Gowen wrote a marvelous thesis titled Studies in the History and Function of the British Theatre Playbill and Programme 1564 – 1914 (University of Oxford, 1998).  In this volume, Gowen considers the function, content, and form of playbills, delineating in detail how these were transformed.

Perhaps the most telling assertion Gowen makes is that there is no precise, absolute way to classify playbills as to their function, content and form.  From the outset, apparently, playbills defied easy characterization.  The roles they assumed, the formats they displayed, the text they contained varied over time.  It wasn’t some linear trajectory.  At times, early in their history, they were simply announcements of an upcoming performance, but soon they also became more, advertisements for a play, for actors, and for theaters.  They often concurrently served as aids to understanding and following a play when they began providing such things as a listing of the cast and a precis of the plot.  They sometimes grew to a large size, the better to promote a performance, but theater patrons were known to fold them to make them more manageable.  They were ephemera, destined to disappear (covered over, torn down, weathered away) once a performance took place, even as they were also long preserved mementos, ways of remembering a performance.  They were pasted to posts (yes, there were posts erected for this purpose) and walls while also being distributed as loose flyers.  They were distributed for free and also sold.  On occasion they were spread around town for free in the morning and sold at the theater in the evening.

So, what, at first blush, might seem an easy distinction to make – between playbill and program – is not.  Without universally accepted agreements on the structure of a playbill, what information it conveyed, and how it was to be used, it may not be surprising that drawing a clear line in this instance may be, according to Gowen, impossible to do.  For instance, one might argue that, when the playbill assumed the function of supporting an audience member in attendance at a performance with appropriate content, a transition had been made and the playbill was now effectively a program.  But, Gowen writes,
If, based solely on its content, the programme is seen to have evolved from the playbill by 1737 with the regular inclusion of a cast list, a more formalistic approach towards the classification of this principal variant of the bill of the play suggests that the programme emerged more than one hundred years later, in the 1850s, by which time the content of playbills averaging approximately twenty-six inches in height and seventeen inches in width was reformatted and printed in small format impositions.  (p.172)
So, in the 18th century, even if the function and content of the playbill were sometimes serving the theater patrons during a performance (arguably hallmarks of a program), the form of the playbill had yet to make the relevant transition.  Interestingly enough, I don’t see Gowen arguing here that the transformation of playbill to program occurred in the 1850s.  Rather, his position seems to be that, given the whole muddled history of the British playbill and program, this distinction lies largely in the eye of the beholder, and perhaps it’s not a distinction that can be made.

The lessons learned from reading Gowen’s thesis offer some help in thinking about questions of transitions in paleontology.  On the one hand, the notion that much depends upon one’s definitions is critical and relevant (what attributes must an ancient species have to be considered a stem turtle?  is there universal agreement on that or is it up for debate?).  On the other hand, throwing up one’s hands in surrender (as Gowen does), because no one else has fashioned widely accepted definitions of the parameters to be applied, isn’t really helpful.

Nevertheless, I cannot fault him too severely because, as far as doctoral theses go, this one is a pip.  Readable, accessible, informative, and often funny (e.g., there was a code of conduct among the folks who pasted up playbills which, among other things, discouraged covering over some rival’s playbill if the glue on it wasn’t dry).

There’s one final instance of a problematic transition that emerges from these playbills of mine.  Both announce a performance by Edmund Kean in the lead role of King Lear at London’s Theatre Royal, Drury Lane – the first for August 30, 1820; the second for February 24, 1823.  (One passing observation – in that 1820 performance, Junius Brutus Booth played Edgar, the legitimate son of the Earl of Gloucester.  Booth was the father of John Wilkes Booth, Abraham Lincoln’s assassin.)

The question of a transition centers on the play itself.  In his compelling The Year of Lear:  Shakespeare in 1606 (2015), English professor James Shapiro describes how, as early as the First Folio, efforts were made to lighten the darkness, the brutality of the play.  As a result, what was acted for some 150 years as Shakespeare’s King Lear was, he asserts, actually Nahum Tate’s revision of the play in which “Lear lives and Cordelia and Edgar will marry and inherit his kingdom.”  David Bevington and David Scott Kastan assert that “the appeal of his [Tatum’s] sentimentalized adaptation was so powerful that Shakespeare’s play simply disappeared from the theater for a century and a half.”  (William Shakespeare King Lear, edited by Bevington and Kastan, 2004, p. xxiii.)

So, when is King Lear actually Shakespeare’s King Lear?  What can be missing without threatening that identity?  Are the darkness and brutality of the ending essential to his play?  Are Lear’s death and Cordelia’s death critical?  Is the Fool crucial?

My playbill of 1823 actually marks part of an important reversal, offering a seminal point in the transition back to a play that is increasingly the one that Shakespeare wrote, rather than being, at its core, Tate’s.  In a performance on February 10, 1823, at the Drury Lane Theatre, a great deal of the play was restored to its original form.  This was considered, by some, to be “the first fully recorded performance of the play given approximately as Shakespeare intended it to be acted.”  (Oscar Fay Adams and A. Wilson Verity, Introduction, in The Works of William Shakespeare, edited by Henry Irving and Frank A. Marshall, Volume VI, 1889, p. 331.)  Though it did not go far enough for other critics.  Still more of Shakespeare was returned to the play in the performance announced by my bill dated February 24, which states in brackets below the title of the play, “With original Passages of Shakespeare restored.”  Nevertheless, is this version really Shakespeare’s Lear when the Fool still hasn’t made it back and Cordelia and Edgar continue to be part of a love story?  I guess that depends upon your definition of what constitutes King Lear.

Saturday, August 6, 2016

The Surprising Garvies Point Museum and Why I Mostly Stopped Paying Attention

The Garvies Point Museum, nestled on the Garvies Point Preserve, a 62-acre tract of woods and meadows along the shore line of Glen Cove, New York, surprised me in several ways.

First, this Nassau County entity belies its local government origins by being a significant museum (is this much too cynical of me?), offering visitors a very rich array of geological, paleontological, and archaeological specimens, focused primarily on New York, with particular attention to Long Island.

Second, the unique geology of the preserve gets due attention in the museum displays, and, so, it is a pleasant experience, and an educational bonus, at that, to be able to walk along the shoreline below the museum and see examples of that geology in the “real world.”

Finally, I was amazed, and rather disappointed, by my inability to read and absorb much of the text-dense signage featured in the museum.  I’ll admit that I finally stopped paying attention to most of the signs.  That concerns me because it suggests I may actually be one of those museum visitors against whom I’ve been inclined to rail – the ones with a limited or, even, nonexistent attention span, the ones who feel a museum should entertain, rather than instruct.  Needless to say, in this post, I’ve shifted the blame for my loss of focus onto the museum.

I realized how seriously my inattentiveness had compromised me after I spent some time researching, as best I could, the Scotsman Thomas Garvie (1775-1842) whose name is associated with both museum and preserve.  He emigrated to the United States in 1803, three years after receiving a diploma in surgery and pharmacy from the Royal College of Surgeons in Edinburgh.  He and his father settled in Musketa Cove, east of New York City.  (“Musketa” means “this place of rushes” in the language of the Matinecocks, the local Native American people.)  Here he practiced medicine (with blood-letting as one of his usual treatments).  Thomas acquired an estate of some 90 acres that ran along the shore of the cove.  Among his varied economic interests was the mining of clay from the high quality deposits on his property; the clay was sold for pottery making.  In 1827, he unsuccessfully negotiated with Cornelius Vanderbilt for a steamboat run from New York City to Musketa Cove where the boats would dock at his wharf.  Though steamboats did begin to travel regularly between the Cove and City, they weren’t under Vanderbilt’s auspices and used a different wharf in the Cove.  This transportation connection would, ultimately, prove critical in turning the area into a summer retreat for the city’s wealthy, but it struggled at first because, so the story goes, potential visitors thought the place’s name was “Mosquito Cove,” a decided turnoff.  So, in 1834, at a town meeting, the name was changed.  The current Garvies Preserve consists largely of land that was part of Garvie’s estate.  The Garvie family cemetery is within the confines of the preserve.

My expectation was that I would find, through this research, that Garvie was the museum and preserve namesake because he was an avid student of natural history, that, perhaps, unusual for his time and place, he understood the geology of why his estate had its clay deposits, or that he was a thoughtful collector of Native American artifacts.  But nothing that like emerged.

Instead, it dawned on me (much later than it should have) that I hadn’t paid close enough attention to the name of the museum and the preserve.  It’s the Point that bears his name (albeit sans an apostrophe in the appropriate place), and, thus, only indirectly the museum and preserve.  So, I was wrong in thinking that the museum or preserve saluted some substantial aspect among Garvie’s intellectual interests.  I suppose an argument could be made that his work with clay deposits could have been sufficient justification (the deposits are Cretaceous in origin and are being squeezed to the surface by weight of the many feet of glacial material deposited much later on top), but that’s no excuse for my failing to pay attention to the actual name.

As for the museum, I enjoyed it and, despite what I write below, would recommend a visit.  I do have to admit I really struggled with it.  Perhaps one of the underlying reasons for my difficulties is that, even with limiting most of its focus to New York and Long Island, the museum seeks to cover a great deal of territory in some detail.  The architects of its geological and paleontological displays had no qualms about exploring complex aspects of Earth’s history such as the geological processes that have reshaped the planet, New York, and Long Island (ranging from plate tectonics to the movement of glaciers during various Ice Ages); the diversity of plant and animal life that have come (and mostly gone) and are captured in fossils mostly found in the State and some on the Island; or, finally, the broad array of gems and minerals created by these geological processes.

The geology and paleontology exhibits in the museum provide a wealth of information which surrounds an impressive array of specimens, including two more instances of fossils being found on Long Island which I was happy to add to my very short list of such occurrences.  A few of these specimens are highlighted below.

Tracks of a carnivorous dinosaur, possibly a Coelophysis, were found in rocks on Long Island; they were most likely carried here by glacier action some 22,000 years ago.  It would seem that Coelophysis was from the very Late Triassic, not the Jurassic as the museum displays would have it.

Impressions of Cretaceous flora have been found in pieces of mudstone, sandstone, and shale where Long Island’s Cretaceous bedrock outcrops in a few places.  The Garvies Point Preserve shoreline is one of those spots.  The kinds of plants captured in those sedimentary rocks suggest that the climate at the time was warm and wet.  Shown below are impressions of magnolia and sassafras leaves.

The workings of glaciers on Long Island appropriately receive a great deal of attention in the museum.  Some erratic rocks moved from what is now Connecticut and further north and found along the preserve shoreline highlight a few display cases.  The modest sized erratic shown below is Ordovician gneiss with fine bands of feldspar and amphibole.  I thought it quite beautiful (no excuse for cutting off a bit in the single picture I took).

Another geological phenomenon that marks the Garvies Point Preserve are concretions that occur in great number along the shoreline here.  Among these are the so-called "Indian Paint Pots" (shown below) and "Rattle Stones."  The first involves pyrite nodules which, when exposed to the air, are transformed into iron oxide and, through wave action, are worn relatively smooth and round.  In Rattle Stones, iron oxides precipitate around lumps of material, primarily Cretaceous clay, which then shrink and solidify inside the concretion – hence, the rattling.

Then there’s "Puddingstone," a conglomerate probably formed initially during the Cretaceous when mud covered an accumulation of quartz pebbles.  The Puddingstone found here is unique and was probably carried onto the preserve shoreline by the glacier of the Wisconsin Age, about 25,000 years ago.  Some nice pieces are displayed in the museum.

Great stuff and just a very few of the treasures on display.  But, sadly, I think there’s too much going on in these jam-packed rooms in the museum and that kept me (and I suspect most visitors) from coming away with much understanding of the important stories told through the museum’s displays.  Yes, it could be that in my dotage my attention span has atrophied, but maybe not.

I have long felt that natural history museums have an obligation to inform even as they might try to increase traffic by pushing entertainment.  It’s a balancing act in which the glitz of the entertainment side often prevails.  If these museums err in striving for the proper balance, I’d rather they err on the side of an information mission.  (I should be careful about what I wish for.)

A museum’s educational mission should be accomplished partly by carefully crafted signage providing accessible, overarching messages.  Less is more in this instance.  Though I want natural history specimens to be put into context, that’s a challenge because the context is often (always?) complex.  Present that context in all of its complicated glory and the visitor is lost; dummy things down too much and, though the visitor might think he or she’s learned something, the science may have been diminished to the point of no return.

Laudably, the Garvies Point Museum has embraced its information mission with a passion, but seems to have gone too far in that direction.  As a result, the visitor is buffeted by wave after wave of text-dense signs.  Sort of like a science fair gone wild.

Consider the following signs and ponder what a casual visitor might learn about the processes generating concretions found at Garvies Point, the Milankovitch cycles and their impact on climate (okay, you might not be able to read the text, but there’s certainly a lot of it), and Cretaceous clay at Garvies Point:

To cope, I resorted to photographing many of the signs in the museum so I could read them carefully later, and I photographed specimens so I might see how they illustrate the stories those signs sought to tell.  I had no choice but to do this, given my inability to read and absorb the text on display while I was walking through the rooms at the museum.

This post gives short shrift to the archaeological side of the museum which is a shame because the museum does nicely with its exhibits on the history of Native American life on Long Island.  Displays and dioramas depict native cultures at various periods.  I assume only a portion of the museum’s collection of projectile points are exhibited; the number and diversity presented to the visitor is striking.

When I walked out of the museum, I reentered a brutally hot and humid summer afternoon.  The sane decision would have been to retreat to the car and begin the drive home.  Instead, risking dehydration and sunstroke, I started along one of the preserve's paths that cross through the woods and meadows.  It led me down to the shoreline which is not only serene and beautiful, it also links back wonderfully to exhibits just left behind in the museum.

Consider the following.

The beach is littered with glacial erratics.

I even came upon some Cretaceous clay bubbling up to the surface of the beach under the pressure of the overlying mess left by glaciers.

I spotted a Puddingstone conglomeration.

And, I also came upon an Indian paint pot concretion with its interior filled with sand.

And, thankfully, none of these specimens was accompanied by a sign.


For background on Thomas Garvie, I relied primarily on material on the Garvies Point Museum and Preserve website, an article titled History of Glen Cove, by Antonia Petrash, et al., which appears on the Glen Cove Public Library website, and an article titled An Early 19th-Century Physician:  Dr. Thomas Garvie, by Peter Luyster Van Santvoord (The Nassau County Historical Society Journal, Volume XXVII, Winter-Spring, 1966).
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