Globigerina Ooze from the H.M.S. Challenger Expedition ~ Not Moon Rocks

The H.M.S. Challenger (a British sailing vessel with an auxiliary motor) spent March 21, 1875, at latitude 7^o 45' N and longitude 144^o 20'  E, just to the west of the Caroline Islands in the western Pacific.  The ship, in the third year of its epic voyage of scientific discovery, would not return to England until May, 1876.  (The picture of the ship is from Report of the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873-76.  Narrative, Volume 1, First Part, 1885, p. 1.)

On this particular day, the Royal Navy seamen and the group of civilian scientists on board (called “the scientifics” by the crew) performed the same grueling tasks that they had performed with monotonous regularity since the beginning of the voyage.  In doing so, they were fulfilling the expedition’s charge from the British government and the Royal Society of London – explore the biological, chemical, and other physical attributes of the world’s oceans.  A specially equipped line was let down to determine the depth of the ocean at this specific location or “station,” measure the temperature at different depths, secure water samples at different depths, and recover a small sample of the bottom material.  In addition, a more substantial sample of fauna was collected from the bottom by means of dredging (at many stations,  trawling was used to secure this sample).  All of this made up a daylong process that required the ship to run its auxiliary engine (thereby burning scarce fuel) in order to remain at station and drag the dredge or trawl across the bottom.  On this day, the Challenger worked station 224.

(I've marked the location of station 224 with an arrow.  I realize that it's difficult to read this chart in this post.  This and other Challenger charts in much more readable size have been placed online by the University of Kansas Natural History Museum.  The section shown above is from chart 31.)

I wrote about the importance of the Challenger expedition from 1872 to 1876 in a previous post in which I reviewed Richard Corfield’s superb book titled The Silent Landscape:  The Scientific Voyage of HMS Challenger, 2003.  The book remains my primary resource on things Challenger.

In the first months of 1875, the Challenger, which had been in Hong Kong for nearly all of the last two months of 1874, sailed to the Philippines, New Guinea, and then the Admiralty Islands.  Of the present leg of its voyage which included station 224, Challenger scientist Henry Nottidge Moseley wrote, “The Admiralty Islands were left behind on March 10th, and a most tedious voyage, of a month’s duration, to Japan ensued.”  (Notes by a Naturalist.  An Account of Observations Made During The Voyage of H.M.S. “Challenger” Round the World in the Years 1872-1876, 1892, new and revised edition, p. 416.)

Among the data collected that day:  the ocean bottom lay 1,850 fathoms (2.1 miles) below the ship, it was 1.3^o C (34.3^o F) at the bottom, and the dredge came up full of Globigerina ooze.  (This information from station 224 appears in “Challenger” Expedition.  List of Observing Stations, Printed for the Use of the Naturalists Engaged in Preparing the Account of the Voyage, by C. Wyville Thomson, 1877, p. 40.)

Globigerina ooze.  Savor the phrase . . . just the phrase, not ooze, but this is such an evocative name, wonderfully capturing the essence of this muck.  The ooze is composed largely (by definition, at least 30 percent) of shells from foraminifera (single-celled protozoa) of the planktic Globigerinidae family.  The shells, the mineral remnants of dead foraminifera, slowly drift down through the water column and collect on the sea floor in staggering amounts.  The resultant calcium carbonate ooze today covers some 130 million square kilometers of the ocean floor; it is one of the planet’s principal ocean sediments, present generally at low and mid latitudes, and at depths from roughly 400 fathoms (2,400 feet) down to about 2,200 fathoms (2.5 miles) at which point the acid level of the water works to dissolve calcium carbonate shells.  Below those depths and in high latitudes, Radiolarian ooze is likely to predominate; this ooze is composed primarily of the siliceous skeletons of radiolaria (single-celled, planktic protozoa).  (Corfield, Silent Landscape, p. 62-63; John O. E. Clark and Stella Stiegelier, The Facts on File Dictionary of Earth Science, 2000, p. 147.)

The Globigerina ooze is often white, but the color can change depending upon depth and the inorganic materials in the mix.  The ooze from station 224 had “a slight rose tinge” and, when dry, was “almost white . . ., slightly coherent, friable, chalky, earthy.”  This description of the ooze at station 224 comes from the Report on Deep-Sea Deposits Based on the Specimens Collected During the Voyage of H.M.S. Challenger in the Years 1872 to 1876, by John Murray (one of the scientifics) and geologist A.R. Renard (1891, p. 108).  (I’m not sure what “coherent” means in this context.)

Murray and Renard’s volume contains some incredibly beautiful plates of the faunal remains that the expedition collected from the deep sea.  One particularly striking figure (Plate XI, figure 5) shows the composition of Globigerina ooze (after a bit of washing) from station 13 in the North Atlantic from a depth of 1,900 fathoms (2.2 miles).  The authors noted that the material shown “consists chiefly of various species of pelagic Foraminifera, together with a few fragments of worm-tubes, Pteropods, and Ostacode valves.”  (Pteropods are planktic snails and ostracodes are crustaceans that live inside two hinged tests.)

Among the Globigerinidae foram shells that made the reverse trip from ocean bottom to the surface on March 21, 1875, at station 224 were many from the foraminifera called Sphaeroidinella dehiscens (Parker and Jones, 1865) (this foraminifera was known as Sphaeroidina dehiscens at the time).  A small sample of those recovered by the Challenger that day in March, 1875, is shown below, mounted (well, most of them remain mounted even after the passage of so much time) in an antique microscope slide from the period.

These particular specimens may not be very old.  As the ocean floors move away from the mid-ocean ridges (where the floor material is created), toward the edges of the ocean basins, they can, over millions of years, accumulate a deep covering of Globigerina ooze.  Richard Corfield writes, “In fact, the oldest sediment occurs at the far western edge of the biggest ocean basin of them all, the Pacific.  In this region the deepest sediment is 200 million years old – an age that places it firmly in the middle of the Jurassic period of Earth history.”  (The Silent Landscape, p. 138)  The S. dehiscens shells shown above are of more recent vintage since the species itself seems to have evolved only some 3 million years ago in the Pliocene epoch.  (Evolutionary Changes in Supplementary Apertural Characteristics of the Late Neogene Sphaeroidinella dehiscens Lineage (Planktonic Foraminifera), Bjorn A. Malmgren, et al., Palaios, 1996, Volume 11, p. 192-206.)

Nevertheless, these foraminifera shells exude a gravitas for me that far surpasses whatever significance I might attach to them because of their age.  These very shells were lifted from the Pacific Ocean 139 years ago by the men of the HMS Challenger.  They are simply amazing because of their connection to this historical voyage.  And there is also the remarkable fact that I own them and have them here before me, encased on a slide.

Well, wait, perhaps it’s not so remarkable that they have come into my possession because many, many people have Challenger specimens and these days they still frequently show up on eBay.  But, how did that happen?  After all, weren’t these specimens collected during an ocean expedition financed by the British government and conducted with a vessel of the Royal Navy staffed by Navy officers and crew?  Why didn’t they remain the property of the British Government like, say, the moon rocks brought back by the Apollo astronauts which are the property of the U.S. government?

The Challenger microfauna very quickly escaped from the scientifics and the other scientists enlisted in the production of the 50 volumes of official reports which took some 20 years to complete.  The sheer number of people involved is one key.  That’s certainly Peter B. Paisley’s hypothesis about the relatively quick appearance of Challenger specimens in the hands of the general public:  “With so many involved in analysis of the Challenger results, ‘leaking out’ of material for mounters was well-nigh inevitable.”  (Aquatic Life and British Victorian Microscopy, Micscape Magazine, October 2010.)  More importantly, the number of microfauna specimens hauled in with just a single passage of the dredge bordered on the countless.  So vast numbers of Challenger foraminifera and radiolaria and other specimens could disappear and no one would be the wiser, and the research would be unlikely to suffer.  In contrast, Apollo moon rocks remain preciously rare and so it’s not beyond the realm of possibility to keep control of all of them, enforcing governmental ownership, in a way decidedly impossible with the microscopic fauna brought home by the Challenger.  But, apparently even the former may be a challenge, since NASA has had a less than stellar record of keeping track of the Apollo moon rocks.  (See, for example, The Misplaced Stuff:  NASA Loses Moon, Space Rocks, by Seth Borenstein, The Boston Globe, December 8, 2011; and NASA’s Management of Moon Rocks and Other Astromaterials Loaned for Research, Education, and Public Display, NASA Office of Inspector General, Report No. IG-12-007, December 8, 2011.)

At least, there isn’t a public marketplace involving the sale, purchase, and exchange of Apollo moon rocks like the one that almost immediately sprang up for microscope slides with mounted Challenger specimens.  By 1879, a popular science journal like Hardwicke’s Science-Gossip was running in its Exchanges column the following ads (Volume XV, Number 173, p. 120):

Wanted, good slides, in exchange for well-mounted slides of “Challenger” sounding. – H.R. 85 Worcester Street, Higher Broughton, Manchester

Good slides of diatom and globigerine ooze (“Challenger” dredging); also parasite from gill of salmon, in exchange for other good slides. – Nicholas Wright, 8 Duke Street, Lower Broughton, Manchester

Two days after quitting station 224, HMS Challenger had sailed to station 225, and the excruciatingly dull voyage to Japan was enlivened by what the scientifics discovered there on March 23, 1875.  The line went out and out . . . and still out some more, until a depth of 4,575 fathoms (5.2 miles) was recorded, the deepest point measured during the entire voyage.  (This area is called the Challenger Deep and is known to be nearly 7 miles deep.)  No Globigerina ooze that day; instead, Radiolarian ooze emerged from the bottom.

Postscript

In his comment (see below), Howard mentioned Henry B. Brady's report on the Challenger foraminifera and the truly marvelous drawings that appear there.  Here is one that shows a couple of shells from S. dehiscens.  This is just a portion of the full plate (LXXXIV) on which these shells appeared.  I made this photograph from the original 1884 publication (Report on the Foraminifera Collected by H.M.S. Challenger During the Years 1873-76, Zoology, Part 22, two volumes - plates are in the second volume); this specific volume is one held in the Smithsonian's natural history library.  Looking at this volume was quite a treat.  All of the plates can be seen at the 19thcenturyscience website.

Shadows in the Distance

This post has no fossils, but it does have stereoviews, Middlebury, Vermont, and The Dick Van Dyke Show.

[Note:  Stereoviews are paired photographs that can offer a three-dimensional view of a image.  They have been discussed previously in this blog at this link.]

I recently acquired a 19th century stereoview of Middlebury, Vermont, and, as a consequence, I found myself reliving an episode of The Dick Van Dyke Show, that wonderful TV series from the early 1960s.  I still revel in the show’s gentle comedic repartee and have never tired of the talented cast who surrounded the lanky, self-deprecating star whose skill at physical humor has been seldom surpassed.  The episode that entrapped me, as I studied my Middlebury stereoview, is a classic titled The Great Petrie Fortune.  First airing on Oct 27, 1965, it is episode 6 of season 5.  (On Amazon Prime, it's listed incorrectly, I think, as episode 6 of that season.)

In this episode, Rob Petrie (Dick Van Dyke) inherits a roll-top desk from his Great Uncle Hezekiah.  In a short movie filmed before his death, centenarian Hezekiah (Dick Van Dyke) tells Rob that the desk contains a fortune but it is wrapped up in a riddle.  He proceeds to dance a wheezy, fumbling soft shoe while singing a verse of Me and My Shadow.  He finally collapses on the desk.

Rob and wife Laura (Mary Tyler Moore) thoroughly explore the desk, revealing a trove of eccentric, mildly funny contents, along with a framed picture of Uncle Hezey as a baby, but no fortune.  In time, the Petries conclude these various, trivial objects were things Hezekiah was sentimentally attached to (for whatever reason) and so had value to the old man.  But they’re wrong.  As Rob more closely examines the baby picture, describing to Laura what he sees (a man standing on a flight of stairs while holding the baby, and, in the background, another man standing alone), he realizes it mirrors the verse from Me and My Shadow.  It’s the shadow, the man at the edge of this photograph taken in 1863 at Hezekiah’s birthplace, Gettysburg, Pennsylvania, that sends Rob into mild hysterics.  He peers at the edge of the frame, then frantically removes the picture:

Rob:  Honey, look at the other guy standing all alone on the stair and feeling blue . . . with a stove pipe hat and a beard.
Laura:  Rob that looks like . . . .
Rob:  The real Raymond Massey!!

I still laugh, though, perhaps, this is a punch line that only works for generations that are slowly aging out of the picture.  Raymond Massey (1896-1983) memorably portrayed Abraham Lincoln in the movies.  Rob has inherited a Mathew Brady photograph of Lincoln (sheepishly, I'll admit that the way Rob manhandles the photograph in this scene now causes me to wince).

And then there’s the Middlebury stereoview (the earlier post cited at the outset describes how to view this stereoview to see the three dimensional effect).

Here’s just the right image.

On the reverse side is the stamp of the photographer O.C. Barnes of Middlebury and the handwritten words, “Main St., Middlebury, Vt.”

Here's how I tell the story.  One winter morning, sometime in the 1870s, photographer Oscar Barnes positioned his equipment at the top of Main Street in Middlebury, Vermont.  He stood opposite the Congregational Church at the northeast end of the street, and looked southwest, down Main into the village.  Snow covered the road and frosted the branches of the trees.  (Admittedly, it might have been early spring, it was Vermont, after all.  Morning?  An informed guess based on what I think are shadows he captured in the photographs he took that day.)

Earlier that morning, I see Barnes (in my mind’s eye only) guiding a horse-drawn carriage, with a darkroom built onto it, to the top of Main Street.  But, no, perhaps that’s too rich for a photographer who advertised in the Middlebury Register that his shop was located “in the poorest old building you’ll find on Main St.,” where “the ceiling is low and the floor far from level.”  So, perhaps he’d trudged through the snow, hauling his equipment himself, and then pitched a tent to serve as his darkroom.  (Appropriately enough, the building housing his shop was called “Poverty Hall.”  Later in the decade, his ads included the line:  “Farm produce taken in exchange.”  Barnes was a regular advertiser in the Register; the first ad cited here ran several times in 1873, including the March 25th issue.  The second is from April 18, 1879; it ran in a number of issues.  Digitized copies of the Register can be found at the Library of Congress’ Chronicling America:  Historic American Newspapers.)

No matter how he did it, he had to get a darkroom to the snowy site; the “wet collodion” process that he and other photographers used at the time demanded it.  In the darkroom, Barnes took glass plates coated with a viscous collodion mixture and bathed them in a silver nitrate solution, making them sensitive to light.  He then slipped a wet plate into a light-proof holder and, at that point, he left the darkroom and hurried to his camera.  The plate had to be exposed while still wet.  He slid the holder with the plate into the camera, which he had to have previously focused for the picture.  He then carefully exposed the plate, relying on his experience to tell him how long to leave the camera lens uncovered.  After that, he resealed the light-proof holder, removed the holder with its precious cargo, and dashed back into the darkroom to develop the exposed plate.

On this particular morning, Barnes created two images because he would be printing stereoviews of the scene.  I hope he had a stereoscopic camera and could make the images concurrently.  Otherwise, he had to go through this process twice, the second time with the camera moved two to three inches to the right or left.  The photographer with a shop in Poverty Hall might well have had to resort to the latter method.

As demanding as the wet collodion process could be under ideal conditions (say, in the confines of one’s shop), clearly going into the field compounded the difficulties, but, to top it all for this particular session at the head of Main Street, Barnes had to deal with cold temperatures which could wreak havoc on the procedure.

And, still, despite the challenges of a nascent photographic technology and the weather, Barnes created a work of art.

In these photographs, he captured the stillness that so often accompanies a snowfall, the softening of the edges and the integration of the whole.  There is harmony here, the village sits gently in nature.  The framing is fascinating.  There is a tunnel effect as the center is framed partly with the snowy branches of the trees on the left in the immediate foreground that reach over the viewer, as well as with the several trees deeper into the picture on opposite sides of the street.  The lamp post on the left imparts a balance to the framing and is, perhaps, the single most important element giving the stereoview its three dimensional effect.

In time, though, I came to find his composition puzzling, mysterious even.  Where is the viewer's eye supposed to come to rest?  What was Barnes really focusing on?  The clutch of buildings in the center of the lower third of the photograph?  Perhaps.  But my attention inevitably was drawn to the shadowy profiles of buildings in the far background, buildings on a hill to the southwest overlooking the village.

Here's a closeup in grayscale.

And that same closeup with the shadowy buildings marked.

I studied those distant buildings and suddenly recognized them – the real Raymond Massey!!

I was looking at Old Stone Row, the buildings that constituted the initial, principal core of Middlebury College – Painter Hall (on the right, built in 1815), Old Chapel (center, 1836), and Starr Hall (left, 1860, burned in 1864, and rebuilt in 1865).    As an alumnus of Middlebury College, I hate to admit how long it took me to realize what I was looking at.

They are shown here in a drawing from 1860.

(This image was downloaded from the Digital Collection at Middlebury on the Middlebury College website and is included here with the permission.  Its resource identifier is a12pf.ls.panoramic.1860.)

I'd like to think that Barnes, with a wink, deliberately hid his true focus.  Regardless, he certainly added an unexpected dimension for me.  And I suppose it only appropriate that, as I close this post (March 12, 2014), Middlebury, Vermont, is slated to be walloped with a massive, late winter snowstorm.


Note

In addition to various print resources which explain the wet collodion process in detail, there are a couple of excellent short videos on the web that delineate what photographers like O.C. Barnes went through to take their photographs.  I particularly like the video from the Getty Museum titled The Wet Collodion Process.  Also very informative is one from the George Eastman House titled Untold Stories:  The Collodion Process.

A Lot of Species?

I struggle with the identification of foraminifera species.  Of course I do, because I believe the differences among these species are often mind-numbingly subtle, and the total number of fossil species is huge.  (Foraminifera are single-celled, shell-bearing protozoa that date back to the Cambrian.  A number of previous posts on microfossils have featured forams.)

As for the first proposition (subtle differences), the distinction between two species can hinge on something as challenging to discern as whether the opening (the aperture) that appears in each shell’s last chamber is "toothed" or not.  By now, I know to couch any identification I settle on with a disclaimer.  For example, the foraminifera pictured below is from the species Florilus chesapeakensis, . . . unless it’s not.

(This microfossil was found at Randle Cliff Beach on the western shore of the Chesapeake Bay, and is probably about 16 million years old – early Middle Miocene.  The scale bar is in microns - a thousand to a millimeter - so the bar is 0.4 millimeters wide.  This identification is informed by Thomas G. Gibson’s Key Foraminifera from Upper Oligocene to Lower Pleistocene Strata of the Central Atlantic Coastal Plain, in Geology and Paleontology of the Lee Creek Mine, North Carolina, I, edited by Clayton E. Ray, Smithsonian Contributions to Paleobiology, Number 53, 1983, p. 355 – 453.)

Recently, I began to wonder about the second assumption of mine (that the number of foram species is enormous).  For much of the time I've worked with the fossil shells from foraminifera, I've felt my life was being complicated by a never ending host of species.  So, when people are foolish enough to listen, I complain, "Good grief, there are 60,000 known species and most are extinct."  (Don’t take this number as gospel, because, as I found while putting together this post, there is no gospel.)

A couple of weeks ago, upon hearing that, somebody foolishly responded, saying that I was overreacting because 60,000 wasn't so large in the scheme of things, and consider, he continued, that the number of bird species might be an order of magnitude larger than that.  (Don't take that observation about bird species as gospel, it's wrong.)

That got me thinking about what the number of foraminifera species (living and fossil) really might be, and whether I was justified in thinking it was a lot, either on its own or in comparison to other taxonomic groups.

On the one hand, the question of the number of species belonging to any taxonomic group or groups is, I think, a scientifically worthwhile one to explore.  On the other hand, expecting a straightforward answer is the mark of an amateur.

Casting my net broadly (why not?), I began with the body of literature about the total number of living species on Earth, those known and yet-to-be-discovered.  Describing the value of addressing this overarching question, the eminent British zoologist Robert M. May observed that this knowledge

is important for full understanding of the ecological and evolutionary processes which created, and which are struggling to maintain, the diverse biological riches we are heir to.  (Why Worry about How Many Species and Their Loss?, PLoS Biology, Volume 9, Issue 8, August, 2011.)

Methods for counting the Earth's known living species vary, as certainly do those for estimating the number of the unknown living species.  For instance, Camilo Mora and colleagues recently applied a methodology based on consistent patterns they found for the number of species at different taxonomic levels in well documented groups.  Applying those patterns to all groups, they predicted that there are roughly 8.7 million eukaryotic species (those having cells with nuclei) on Earth, give or take 1.3 million.  (About 1.2 million species of the grand total, they estimated, were known.)  Previous estimates of the total number of living species, known and unknown, ranged from between 3 and 100 million.  (Camilo Mora, How Many Species Are There on Earth and in the Ocean?, PLoS Biology, Volume 9, Issue 8, August, 2011.)

For their work, Mora et al., turned to the online Catalogue of Life.  In 2001, the Integrated Taxonomic Information System (a group of government and other organizations in North America), and Species 2000 (a worldwide collaboration of taxonomists) joined forces to create the Catalogue of Life with the goal of listing every valid living species on Earth.  I applied this database to my foraminifera count.  In the Catalogue's 2013 Annual Checklist, the order Foraminiferida is listed as having 1,348 (extant) species.  Damn, I thought, not enough!  (So much for a dispassionate search for truth.)

But, for the moment, I decided to accept that number (and the Catalogue's taxonomic placement of the foraminifera, more on that in a bit) and see how it compared to the other orders in the Catalogue.  I managed (with a some tedious work) to create a list of the number of species in each order included in the Catalogue across all kingdoms.  Of this total of 1,069 orders, only 93 featured more total species than the Foraminiferida.  The mean number of species per order was 1,263; the median was just 56.  So, even this suspiciously small number of foraminifera species is at the upper end of the spectrum of orders in terms of valid living species.  Good.

Even better, my sense of problems with the Catalogue's count of foram species was validated when I learned that, for their estimates of protozoa species in the ocean, Mora et al. turned to the World Register of Marine Species (or WoRMS), a government and privately funded effort led by taxonomic experts, because its protozoa data were much more complete.  The Catalogue and most other taxonomic analyses place the foraminifera in the protozoa kingdom.  WoRMS includes the World Foraminifera Database, which, as of February 27, 2014, listed 6,625 valid modern foraminifera species and 1,731 valid fossil species, for a total of 8,084 species.  (I assume the total is less than the addition of the modern and fossil counts because the two categories are not mutually exclusive.)

That's better, but still not 60,000, and the number of fossil species seemed laughingly low.

Ultimately, I did rediscover the source of that nice round number I'd been using.  It was in a volume I turn to often, Donald Prothero's Bringing Fossils to Life (1998).  He wrote,

Over 3600 described genera and perhaps 60,000 species of foraminifera are currently recognized, making them more diverse than any other group of marine animals or plants.  (p. 190)

Unfortunately, I have to assume he lumped living and fossil species together.  The source of his estimate is probably Stephen J. Culver’s 1993 piece on foraminifera (Chapter 12 in Fossil Prokaryotes and Protists, edited by Jere H. Lipps) which isn't any more precise about what's included or how the number was derived.

Of course, I recognize that any count of species (living or fossil, targeted to a single taxon or all taxa) is burdened by myriad challenges, some of them potentially fatal.  Taxonomies can be revised substantially over time.  What it means for a species to be recognized or valid may not be consistently applied.  A mixing of counts of known species and estimates of as-yet-to-be-discovered species may muddy the water.  And the definition of what constitutes a species is probably one of such an effort’s biggest bugaboos (particularly problematic for efforts like Mora's which cross multiple taxa).  According to Lynn Margulis and Karlene V. Schwartz much of this applies to foraminifera taxonomic work:

Unfortunately, although foram lifecycle stages often correspond to extreme changes in shell morphology, paleontologists assume that each morphotype represents a different species.  Protistologists and geologists have different aims and terminologies; thus, the taxonomy of the foraminiferans is in rather a mess.  The bewildering complexity of their organisms and their life cycles assures both groups of scientists much taxonomic work for a long time. (Five Kingdoms:  An Illustrated Guide to the Phyla of Life on Earth, 2nd edition, 1988, p. 119.)

Even if mess is too harsh a term, the higher level taxonomy of foraminifera is in flux.  Efforts have been made to elevate the foraminifera from an order to a class or to a phylum (see discussion in Short Treatise on Foraminiferology (Essential on [sic] Modern and Fossil Foraminifera), by Jean-Pierre Bellier et al., first published online July 1, 2010).  Either of these changes has been adopted only in some taxonomic treatments of forams.  The rest stick with order.  Most confusing.

So, where does that leave me?  One approach would be go with the 60,000 species estimate, despite its squishiness, and, further, assume that perhaps 6,000 to 7,000 of those are living and the rest fossil.  Another would be to stick with the World Foraminifera Database and its much lower, but possibly more defensible, totals, rounding them for ease to 6,600 modern and 1,700 fossil species.  But when I poked around the Database I was pleased to find that its administrators make it clear that they recognize the number of fossil species is a substantial undercount of the valid names that it should list and which "will take many years to add in."

So, for the moment, I will continue to use the 60,000 figure.  I'd like to have proof one way or the other (though, the higher the better).

One last item - the assertion that the number of bird species dwarfs the foram species count.  At least here I have certainty - it's wrong.  If we accept the Catalogue of Life as our source (Mora et al. accepted it for every taxa except marine protozoa), then the current number of extant species in the Aves class is 9,924.  (Back in 1946, the eminent evolutionary biologist Ernst Mayr offered up a hard count of known species, 8,616, and posited that the "final" total would certainly be within 10 percent of that, if not much closer.  (The Number of Species of Birds, Auk, Volume 63, January, 1946.))  So, counts of known living species of birds and foraminifera are not an order of magnitude apart.

Perhaps, there are many living bird species yet to be discovered.  Well, no, not according to those who study these issues.  Daniel P. Bebber et al. explored how changing rates over time in the discovery of new species within different taxonomic groups could be used to predict how many species remain to be found.  (Predicting Unknown Species Numbers Using Discovery Curves, Proceedings of The Royal Society B, Volume 274, 2007, p. 1655.)  For birds, they asserted, the unknown number should be small given that the count of existing bird species was “more or less complete.”  The best estimate from their methodology was that the actual number of living bird species – those yet to be discovered added to the 9,924 already known – was between 9,994 and 10,061.

What of the fossil record?  For birds, I'm not quite sure what to make of it.  There’s debate over its adequacy and its reach (how far back it goes).  It's generally thought that the hollow bones of birds don't fossilize readily and, as a result, many feel the fossil record is weak and likely to remain so.  (See, for example, English ornithologist Ian Newton's The Speciation and Biogeography of Birds, 2003, p. 16.)  That means that relatively few fossil bird species may be known.  For instance, Neil Brocklehurst and his colleagues looked at avian fossils from the Mesozoic Era and concluded there were 124 valid bird species in 82 genera identified from that era.  (The Completeness of the Fossil Record of Mesozoic Birds:  Implications for Early Avian Evolution, PLoS One, Volume 7, Number 6, June 2012, p. 4.)  I haven't found decent counts of the number of fossil avian species known from the Cenozoic.

I seriously doubt that the number of fossil species of bird could ever match that of foraminifera whose shells readily fossilize and whose traces in the fossil record go back into the Cambrian.  Lots of time and lots of species.

I've come full circle.  Though I may be wrong about it, my impression remains that the number of foraminifera species, living or fossil, is inordinately large.  And all of those species are intent on complicating my life.