Identifications…

January 11th, 2011
Ah… well, yesterday I started to do some research on an article which may have the title of  ” The Vampires of the Sea.”  A twilight  article dealing with…

those bloodsuckers, bar none – Pyramidellid snails.   

Whether or not I develop this article fully depends on a lot of things, not the least of which the direction my muse (and I do have one – a characteristic I find “amusing”…  :-) ), takes me.  And also, of course, whether or not, I can find an editor who will accept it.  Anyway I am still in the very early stages of this thing, and I am trying to find some more background information about Pyrams. 

Now, like Yogi, I figure I am a bit “better than the average bear” with my knowledge of the group, but I really need to know more before I do anything that can be considered to be a reasonable and – hopefully – entertaining article about them.

Basically, the Gastropod family Pyramidellidae is a very large group of small… white… snails without any really nice identifying characteristics.  There are, quite literally, thousands of names applied to these snails, and how those names relate to the actual species – if any – of those snails is really open to question.  As with many marine groups – probably as with MOST marine groups – of animals, they are a taxonomic mess.  There are three basic reasons for this, the primary one is that they are all – dare I say it, again – small,  white, and feature-less snails.  If you think about it, once you have the basic constraints of a small, helically-coiled, shell, there are NOT a lot of ways that those constraints can be varied.   In point of fact, back in the 1960s, a paleontologist named David Raup, wrote a series of nice papers noting that virtually all marine animals with a “shell” can be easily described mathematically (Raup, 1962; 1966; 1969). 

The term “shell” in this sense is restrictive and excludes arthropods – even though they are “shellfish” they don’t have a “shell” in the way that Raup meant: “a non-living external covering to the animal.”  What arthropods have is an “integument” – a covering that is made of an intricate and complex fusion of living and secreted elements that is an integral part of the animal’s body, interiorally and exteriorly.  If you try to remove a shrimp’s “shell,” you are left with a mass of dead flesh.  If you try to remove a snail’s or a clam’s shell, you will find that, in many cases, it is quite possible to do this and still have a living animal.  And that animal may remain alive – in the case of some snails – indefinitely.  Clams without a shell perish in short order, as they can’t feed.  But snails without a shell can generally do everything shelled animals can do.   Everything, that is, except withstand the bite of a predator’s jaws.  Virtually every biologist who studies large populations of marine snails occasionally finds a shell-less one; probably an animal whose shell was eroded away by a sponge, or whose shell was cracked by a crab and, by a miracle, the shell was removed.  As an example, over the course of three years, I encountered two almost-naked specimens in one species, Ophiodermella inermis, that I worked on many years ago.

Ophiodermella inermis, photographed in Dyes Inlet, Washington.

Anyway… Raup found that virtually all mollusk and brachiopod shells were basically helical in shape, and that all fundamental shell shapes could be described by only three parameters, 1) the shape of the shell’s aperture, 2) the rate at which the shell’s aperature coiled around the central axis, giving the width of the animal, and 3) the rate at which the coiling moved along the central axis which determines the animal’s length.  As all of the functions occur simultaneously, how each of the parameters varies in relationship to the others changes both the absolute and relative proportions of the shell’s shape.

This diagram below shows how the shell parameters determine the difference in shell shapes for some snails commonly found in marine reef aquariums. The top shows a Nerite; here the shell aperture just moves in a spiral around the axis of coiling and moves outward at a rate that is not very large.  This results in a spirally-coiled shell where the whorls appear to overlap.  The other shells are trochoideans.  And here the parameter of “aperture shape” is circular.  The aperture moves around the axis of coiling at various rates – giving a turbinate or trochoid shape.  Additionally, the aperture moves along the axis of coiling determining whether the shell is squat or elongate.  Although the flat Stomatella seems to be very different from a conical Trochus in structure, with a little thought, it is easily possible to see how those shell shapes are related.

.Shell parameters illustrated by various snail shells; all shells grow in three dimensions but the position of the aperture in each successive whorl may change due to only 3 parameters. A. Growth of a shell where the aperture shape moves in a spiral within one plane; the nerite shell is an example of this. B. Here the aperture moves along the axis of coiling but remains tangent to that axis; the illustrated turbinid is an example of that growth. C. Here the aperture moves along the axis of coiling, but also translates or moves outward from that central axis. An opening called an umbilicus in the center of the shell is the result. The illustrated trochid shows this growth form, with the earlier positions of the growth generating aperture shown in gray. The shell of Stomatella is auriform, an extreme example of the prominence of the whorl translation rate.

Given that all molluscan shells can be basically described in this manner, if shells lack much distinctive coloring, sculturing, or extra ornamentation, it should be apparent that there really are not a lot discrete characteristics that can be used to uniqually differentiate any given shell from all others that are basically similar in shape.

That lack of potential characters is the first factor that has caused taxonomic problems with pyramidellid shells.

The second and third problems were two malacologists, William Healey Dall and Paul Bartsch.  Dall was the first curator of mollusks at the United States National Museum (aka the Smithsonian Institution).  Bartsch was his “disciple” and successor.  As curators at the Smithsonian, a lot (really A LOT!!!) of specimens (= dead shells) were sent to them by various collectors.  As they tried to identify these shells, they often found that the shells were not “quite” like shells in the museum’s collection – or in other museums’ collections.  This meant that these shells were then new to science and needed to be taxonomically, or scientifically, described.  Virtually all animals that are described from United States regions or by American authors have representative or “type” specimens deposited in the Smithsonian’s collections, so they had a lot of comparative material.  Presently, that is a huge number of specimens, several millions.  Back in Dall’s time, the collections were a lot smaller… but still relatively very large…  So, they had a lot of material with which to compare any given specimen in their descriptions.  Thus, if they decided a given specimen was a “new” species the odds would seem to favor the fact that it was new. 

Maybe…

Typically what these two ol’ boys did, was to let specimens accumulate until they had enough to write a short (or sometimes very LONG paper describing them all).  At the time, the custom was to describe a molluscan species on the basis of one shell. 

ONE

THE

TYPE.

The type was supposedly an “average” or representative shell that “typified” the species.  By the way, Dall and Bartsch were by no means alone in the way in which they described “their” species.  It was the standard method of the era.  They were, however, especially prolific, and it seems, especially “gifted” with the inability to find unique precise and useful descriptive terms.  Simply put, many of their descriptions are “precisely ambiguous,” they are written in ways that seem to precisely describe the specimen, but which don’t allow a reader to determine if a given questionable shell that they are holding in their hand is from that unique species.  I think this was because they didn’t include much or any information addressing variations between specimens of the same species.

And what about those variations?  Well, Dall, at least paid lip service to the concept of variation, but he generally didn’t include any useful way to describe variations in the species he described.  Any good field biologist knows that variation is quite literally “the stuff of life.”  For example, for little white snails, such as pyrams, if one collects one hundred specimens from a known species, they will vary in length, width, the number of whorls, slight color variations occur, the proportion of length to width will vary a bit, the number of ribs on whorl may vary, and on and on and on…  One specimen really can’t do it.

Nonetheless, the conception of a species at the time, which was reinforced by rules of Linnaean taxonomy implied that there was no variation in a species.  This was a result of considering all species to be divinely created.  If a creator designed each species, he/she/it/they would obviously get it right the first time and there could be no variation.  That was all fine and dandy up until the publication of The Origin of Species in 1859.  Once the concept of evolution became established, the concept of a species HAD to include variation.  And so it did.

In concept.

But in practice…  Well, let’s just say the idea of variability in a species was not an easy one to get across.  Modern descriptive statistics is just that, modern, so at that time there was no formal way to estimate variability.  The concept of a standard deviation wasn’t there.  Even including a range of sizes in a species description was rarely done.

In essence, for any species – the idea of that species was “crystalized” within a single typical specimen, the type.

Over his lifetime, Dall described 5,302 species in every group of animals defined at the time, from mammals to mollusks.  Most, however, were snails.  Bartsch described an additional 905.  The heyday of these descriptions extended from the 1870s through about 1925 for Dall (several years after he died, actually, as Bartsch published some of Dall’s descriptions after his death).  Bartsch retired in 1945 and died in 1960, and I think his last taxonomic publications were in the 1950s.

Modern day molluscan taxonomists who work in the Pacific where these men had the largest taxonomic effect have a love-hate relationship with them.

Love…about 0.000001%,  Hate… well, do the subtraction.

Simply put, it is essentially impossible to differentiate most small snail species described by these men.  They gave lip service to the concept of species variability, but using the typological approach and their writing style such variability was impossible to descibe.  Interestingly enough, that is not the case with many other prolific describers of molluscan species that were writing at the same time.  Henry Pilsbry was another malacologist who described a lot of species; according to his article in Wikipedia, he wrote over 3,000 scientific papers and described over 5,000 species.  His descriptions have stood the test of time well, so the problems with Dall and Bartsch were due to Dall and Bartsch.

How bad is the situation, really? 

Pretty bad.   Really!

For example, if a large collection of pyramidellids or other small snails is taken from one bay or locality, their parameters will vary, of course.  If those specimens can be determined by other means (ecological parameters, for example) they are all found to by one species, it would be nice – satisfying even – to put one valid name on them.  And… by examining the works of Dall and Bartsch, one can often find numerous – perhaps several dozen – entirely satisfactory species names that will fit within that single collection of specimens from a single species from a single small bay.

Amongst the references I downloaded (thanks to Google’s digitizing, many books in the public domain are downloadable) was:

Dall, W. H. and P. Bartsch. 1909. A monograph of West American Pyramidellan Mollusks.  United States National Museum, Bulletin 68. 1-258 pp, 30 pl.

This monograph contains 258 pages of species descriptions…  And 30 plates of illustrations…. As an example , take a look at this one.

This is one of many plates of illustrations showing species of TurbonillaTurbonilla is one of the genera of pyrams that has species that will attack Tridacna.  Do you think you could use such images as these to differentiate between any two them reliably?

Could anybody?

When I discuss specific animal groups in my articles for the reef aquarium hobby, I like to give examples of those species…

CORRECTLY IDENTIFIED examples of those species.

And, please excuse me, so that I may now go and start beating my head against the wall.

Because it will feel soooo good when I quit. 

An aside… 

Oh… for those of you who might know mammals, the Dall sheep and the Dall porpoise were named after William Healey… AND here is something I will bet you probably didn’t know.  His name “Dall” was pronounced rhyme with “Gal,” NOT “Gall,” as it is most often used.   See… I even give you a piece of “party” trivia to amuse your friends with.  Of course, if you do so, you risk never being invited to such parties again.

References:
Raup, D. M. 1962. Computing as an aid in describing form in gastropod shells. Science. 138:150-152.

Raup, D. 1966. Geometric analysis of shell coiling: general problems. Journal of Paleontology. 40:1178-1190.

Raup, D. M. 1969. Modeling and simulation of morphology by computer. Proceedings of the North American Paleontological Convention. September 1969:71-83.

Until later,

Cheers,

Sky Sharks And SCUBA

December 19th, 2010

Hi Folks,

My wife and I got treated to quite a show yesterday.  For several hours, a male prairie falcon was cruising around our yard hunting doves.   These latter birds are Eurasian collared doves, one of several introduced pest birds (think large white/gray/tan pigeons) found locally – thesea are  probably descended from birds released by some non-thinking idiot who decided it would be cool to release doves symbolizing something or other at a ceremony somewhere near here.  Anyway, said skyrats appeared about four years ago, and have been doing well here.

Eurasian Collared Dove

Periodically, though, a truly native sky shark comes by to thin the herd a bit, and that is what happened yesterday.   It was great entertainment to watch the falcon, though I doubt the doves thought so. :-)  I saw him miss his target by inches on one pass; the dove was surprisingly agile in the air when the situation warranted!   The falcon was around for a while, and then vanished.   I hope he finally got dinner and settled down near by to enjoy his repast.

Almost exactly a year ago, we had a similar opportunity to watch a goshawk for a few days, and the second picture, below, shows the final outcome.  The first picture was taken a few days before the second one, and it appeared to be the same animal.  In the second image, the hawk is standing over his plucked prey that he has been eating.

Sharp-shinned Hawk in the poplar outside my office window.

Sharp-Shinned Hawk and Dinner

It was an amazing show.

Of such events, are the sciences of behavioral biology, or ethology, and ecology, made.  And people who study these things in terrestrial environments truly lose out.  I used to tell my students that one of the very neat things about being an ecologist who worked subtidally using SCUBA was that one got to see a lot more interactions than one’s terresterially-bound counterparts.

If you think about it, how many times have you seen a predatory animal in nature around you (excluding those events caused by humanity or human pets ) actually kill and eat a prey organism?  I would wager that the total sum of those events witnessed by anybody is pretty small; I know it is with me, and I look for them.  It is possible to calculate some sort estimat of the odds of seeing such an interaction at any given moment.  For example, if a person is 35 years old, that person has been alive about 1 billion seconds.  If each second is a discrete a moment of observation, the rough, back-of-the-envelope odds of having seen such an event through that person’s lifetime are easy to work out.  First, assume that about of the third of the time has been spent sleeping, so subtract a third of the billion away, phffftt!, and now there 667,000,000 million potential moments of observations.  Then assume that for the first third of the persons’s life she or he was effectively unaware of the world (childhood, teen-aged years, and so forth), so subtract a third of the previous remains and now there about 444,700,000 million potential observational moments.  Now, drop out a another third for meals, and other daily mindless activities, and now there about 296,400,000 million observational times.  Being generous, let’s say our victim subject was outside observing nature 1/10 of each day (and I think that will be a vast over estimate for most folks, but, what the hey, let’s go with it), so now there are 29,640,000 potential moments of observation.  And if that person witnessed 10 natural events wherein one animal killed and ate another (and I suspect that would an overestimate), that means our subject’s odds of seeing such an event were 10 in 29,640,000, or 1/2,964,000, or (very roughly) 0.0000003.

Pretty slim odds (!) of seeing some interesting natural event such as predation.

Back to my point about working underwater in the marine world, I could see animals kill and eat other animals many times during a hour’s dive, and often did so.   Below are a couple of images  recording some of those times (and be sure to click on the sculpin image to see the shrimp’s antenna).   Obviously, the moral of the story, of course, is that one must dive to really observe and understand nature.

A Buffalo Sculpin, Enophrys bison, that has just eaten a shrimp, note the antenna visible protruding from the mouth.

A red rock crab, Cancer productus, eating a scallop.

Yeah, sure!!!

But the point that visible large animal to animal interactions are more evident in the marine environment is, I think, a valid one.

Behavior and Marine Aquariums

Thinking about the point made above, and making a not-so-tortuous connection to marine aquaria, those boxes of water full of critters may be (depending, of course, on how the boxes are set up, and what’s in them) quite reasonable analogues to a natural environment.  And that means, any aquarist with such a tank should expect to see predatory (and other “natural” ecological or behavioral) events occurring with some reasonable frequency in their systems.

And, of course, all of us aquarists (or at least of us who observe our systems) do see these events.  Everytime we feed some live animal to our livestock, we see predation, albeit those are staged events, but with suspension-feeding animals, corals for example, within the staged event, the actual feeding behavior on the part of the coral, is likely essentially the same as when the “real thing” occurs in nature.  But even if those “wo/man-made” events are factored out, all aquarists have seen unintened predation occur in our systems, and sometimes rather frequently, as when when a newly-observed acoel flatworm on the aquarium wall is seen to capture and eat a copepod.  In fact, by observing some of these types of events any aquarist worth their artificial (sea)-salt can – for some animals, at least – see interactions that have never been seen in nature, and depending on the interaction – such as with the flatworm and copepod example – such events may be exactly what occurs in the real world, or a mimic so close that the difference is immaterial.

So, folks, on this cold winter, while the snow outside blankets the northern hemisphere, those of you with coral reef aquaria kick back and relax and enjoy the tropical world in your living room.

It’s a world of your making and if you have done your job, properly, it is a VERY real world.

For the rest of you, it is time to shovel snow!

Until later,

Cheers,

Coral Problems

December 17th, 2010

Hi Folks,

A most interesting and interesting article discussing the problems with identifying stony corals, in particular, some species of Hawai’ian Montipora has recent been published.

The background for the article is that last year several parties petitioned to have 83 stony corals to be listed under the United States Endangered Species Act. The National Marine Fisheries Service (NMFS), a branch of the National Oceanic and Atmospheric Administration (NOAA) is charged with assessing the coral species in question to determine, among other things, if they actually are endangered.  If the corals are listed, the act is supposed to provide some more protection for the species, and probably most importantly, designate critical habitat for these corals.

Of course, the whole “assessment” process ultimately depends upon somebody’s ability to identify individual colonies of coral species in question and that, in turn, depends upon the validity scientific description of those species.  The basic fundamental issues are:

1) Is the given species well-enough described to be reliably identified?  Keep in mind, that by being listed on the petition, at least somebody thinks the indivual colonies in that species can be identified.

2) If the species is identifable, can it be assessed to determine if it is endangered?

The article discussed in the Coral feature was officially published on 2 December, 2010, in the electronic (online and free access) peer-reviewed journal, PLoS One:

 

Forsman ZH, Concepcion GT, Haverkort RD, Shaw RW, Maragos JE, et al. (2010) Ecomorph or Endangered Coral? DNA and Microstructure Reveal Hawaiian Species Complexes: Montipora dilatata/flabellata/turgescens & M. patula/verrilli PLoS ONE 5(12): e15021. doi:10.1371/journal.pone.

I urge you all to read, at least, the Abstract (= the authors’ short summery) of the article, but I am also a realist and realize that while a few of you will look at the Abstract, and some of you may actually read or download and save the article, most people who scan this blog probably won’t.

So…

Here is a brief summary of the summary – if you will, an abstracted abstract.  And if this is creative document would it then be “abstract art?”    Yeah, I know, “Boo!… hiss!”

The researchers examined the genetic codes for a relatively large number of well-known and well-characterised proteins found in the corals’ cells, as well, they also looked at how the subcellular structures called mitochondria vary genetically between the samples.  They also microscopically compared, in fine detail, some of the visible physical structures of each specimen.  

When added together, these different examinations revealed four distinct groupings of specimens (called “clades”), and when each specimen was identified with traditional taxonomic methods, the four clades contained these species: I) M. patula/M. verrilli, II) M. cf. incrassata, III) M. capitata, IV) M. dilatata/M. flabellata/M. cf. turgescens.  So, sophisticated statistical analyses of skeletal microstructure and genetics separated specimens of 7 “species,” based on traditional taxonomy, into 4 groups that represent -probably- actual groups.  I think whether or not one wants to consider that each of these groups represents a species is probably dependent on how one feels about this type of analysis.  To me, yup, I’ll buy in to consideration of each group as representation of a species.  The microcharacters of the size and shape of verrucae or papillae were the only reliable physical characters that could be used in identifying the groups, while gross features such as any aspect of colony-level morphology was so highly variable as to be useless.

The authors noted that previous studies on how observable structures in corals vary from specimen to specimen have revealed that fragments taken from the same colony can exhibit strikingly different growth forms if grown in different environments.   Additionally, the extent of both genetic and morphological intraspecific variation in corals is poorly understood. This is clearly creates problems for assessment of species in the context of the Endangered Species Act as  structurally-based taxonomy – not molecular or genetic information – is the current basis for estimating species distributions, abundance, and extinction risk.

This study identified no fixed genetic or fine-scale morphological differences between M. flabellata, M. cf. turgescens, and M. dilatata, or between M. patula and M. verilli; in other words, these 5 named species appear to be only 2 natural species.  The authors noted that the geographic ranges of these groups are likely to extend beyond Hawai’i into the central Pacific and that individuals within “species” of these complexes are either actively interbreeding (which means they are not separate species), or they are from separate species that are very closely related (e.g., evolutionarily separated within the last one million years) and cannot be distinguished from one another.  Now that these complexes have been identified, work is needed to determine if the nominal species within each complex freely interbreed.

Finally, the authors note:

Unfortunately, this study provides little guidance for determining if these specific species are valid and should be listed under the ESA, but perhaps more importantly; it highlights major gaps in the present understanding of species as opposed to population-level variation in corals. This study is an example of how knowledge of species boundaries in corals is not only necessary for understanding patterns and processes of biodiversity and evolution, but is essential for conservation.

In short, the article is a “fun read.” 

One of the many take home messages is obviously that corals are exceptionally difficult critters to identify.  Generally, if we choose the proper characters, we can identify them to genus.  Beyond that… don’t even try.  As it stands now, we have so few data across the range of most tropical stony reef-forming (and presumably, non-reef forming as well) corals, that distinguishing any specific species is an impossible task. 

Enjoy the article!!

Cheers,

Angels of Death

December 15th, 2010

Hi Folks,

Here are a couple of great links pirated from the Deep Sea News blog.

The subject of that blog’s discussion is what the author calls “sea angels,” rather beautiful predatory swimming snails in the genus Clione.   Embedded below is a movie of one swimming lifted from YouTube.   These pretty liddle snails were called “sea butterflies” in the Pacific NW – off the British Columbia and Washington coasts, where I had many chances to observe them, both during and after my graduate studies.

In that area, the common species reaches lengths of about 2 cm – 3cm, roughly an inch or so, but most of the individuals I have seen have been smaller.   These are shell-less snails, found in the water of the colder oceans through out the world.  They swim all their lives.

“Sea angels” and “sea butterflies” ….. ah…. such cute names…

Sorta like calling a hunting tiger, “Fluffy,” or a semi-starved, very hungry, fresh-from-hibernation-and-in-a-(REALLY)-bad-mood Grizzly bear, “Snuggles.”  

Individuals in Clione species snails are specialized predators that appear obligately bound to eat only another pelagic swimming snail.  At least that is the reading from the snail biology gospel; in reality I don’t think they have been studied well enough to know if they have any alternative prey.   While Clione individuals lack shells, their prey do have shells and look rather like a regular snail; both species have large extensions of their foot which they flap like wings.  This gives all of these snails the group name of Pteropods, or “wing-foot,” snails. 

I have embeded another movie, this one showing Clione individuals attacking and eating their prey, Limacina.  And as you watch the movie, I think you will see why I consider the name of Sea Angel to be a bit…. inappropriate.  Unless, that is, it is modified to be the “Sea Angel of Death.”

Swimmers near bathing beaches should be thankful that Clione individuals don’t reach about 2 m long (6.6 ft) and have a taste for humans.

A few times when I was teaching a course about Marine Invertebrates at a university field station/marine laboratory on Vancouver Island, I was lucky enough to be able to have had my theaching assistants collect some individuals both Clione and Limacina within a day or two of one another.   For the class, I would take a large graduated cylinder – these are about 3 feet long and several inches in diameter.  And then I would put in one or two Clione individuals and let them become acclimated, typically that only took a minute or two.  Then I would have the students gather around, and would introduce two or three Limacina.   The rapidity and apparent “ferociousness” (this is a anthropomorphic adjective, but after watching the Clione at work, it seemed to fit, but probably a better adjective is “efficiency”) of the attack would typically leave the students, quite literally, speechless.

Most of the time marine biologists (and I suppose other folks who see such things) typically regard snail predation as a slow and rather leisurely process (albeit animals like Cone snails will also demonstrate the other extreme).  After all, an oyster drill (a muricid whelk) drilling a hole through a bivalve shell is hardly action that is exciting, except, perhaps, to the participants.  

Then, if you are very lucky, you get to see something like Clione attacking a Limacina.  Wow!!!  It kinda blows away the stereotypes and misconceptions…

If you think about this system, wherein one pelagic snail lives by preying only on another pelagic snail, a bit further, I think it is really cause for wonder.  At best, Clione – the predators – are found in aggregations (I really don’t think one could call them “schools,” or “herds” or “flocks”) or patches maybe several meters in volume, and with a few snails per cubic meter.  More often the patches arel larger a few hundred meters on a side, and the density is one or two snails per 5 or 10 cubic meters.

So… lots of water… not many predators….just swimmin’ along being their little sea angelic selves, and with a LOT of water between them.  

Now… the prey – and the same sort of situation.  Lots of water, not many prey.

Two diffuse patches of animals in a very large body of water, what are the odds that any one snail of either species will encounter an individual of the other species?

Well, the odds have to be pretty good or the animals wouldn’t be here!  But still, it is not like these are pedestrians on the sidewalk along a busy street bumping into one another. 

I don’t know of any research that has been done investigating these interactions ecologically in nature.  I suspect the logistics of such research would make it prohibitively expensive (lots of ship time, for example), but the questions raised by the necessity of such interactions are really pretty interesting, I think you will agree.

Perhaps they are being studied at the present.  The author of Deep Sea News blog mentions a student/researcher/photographer, Natalia Chervyakova of Moscow University, who has taken some images of Clione feeding in nature – an amazingly difficult proposition.  Here are some of her images from the White Sea.  These are some of the most spectacular underwater macro photographic images I have ever seen.   And having taken thousands of underwater shots, including a number of planktonic macro shots, I can attest to the skill and effort involved and demonstrated by these images.  I would have killed to have been able to get one – 1 – image like these.  I would have killed a lot more, to have had the skill to be able to do it repeatedly.

Finally, shelled pteropods, similar to Limacina in some regards, are at the base of the zooplankton food chain throughout much of the world’s ocean.  They are especially abundant in the very rich fishery regions of the cold temperate and boreal seas, where they eat phytoplankton and convert it into their tissue. In turn they are eaten by many other organisms.  Two or three times removed, they are the fish flesh or krill that is harvested for human consumption or use, to say nothing of the top predators in those ecosystems, whose trophic position has been usurped by humans.   These pteropods have aragonitic shells, and as the oceans acidify they will be amongst the first to be affected by this interesting tiny experiment in the alteration of the ocean’s physical parameters.  “Affected” … A nice polite word for “Exterminated” by both human action (the addition of massive amounts of excessive carbon dioxide to the atmosphere) and inaction (no attempt to slow down those additions).

The sheer and utter stupidity of the human species, both individually and collectively is truly mind-boggling.  Here we are, well on our way into the sixth major mass extinction event in the Earth’s existence, and politicians play games of posturing over public images and the majority of the public wastes its time paying attention to the foibles of ephemeral pseudo-entertainer or some ridiculous sporting event.  I guess over the symbolic grave of humanity, our epitaph should be, “Considering their potential and abilities, they had their priorities straight.”

Until later,

Cheers,

Ah, The Good News Just Keeps On Coming…

December 9th, 2010

Today’s reading material is by J. E. N. Veron, courtesy of a link in the Yale 360 blog, “Is the end in sight for the world’s coral reefs?”

Of course, the aswer to the question posed in the title to this essay is obvious and is rather succinctly stated by Veron as well:

“It is a difficult idea to fathom. But the science is clear: Unless we change the way we live, the Earth’s coral reefs will be utterly destroyed within our children’s lifetimes.”

Now… for a show of hands… Is there anybody out there that thinks we will change the way we live, 1) at all, or 2) in time to save coral reefs from going the way of the non-avian dinosaurs? 

Hey, its not all bad, we could start a betting pool as to the year or month when the scientists of that future time could declare that the last coral reef finally wasn’t one anymore!

Any regular (if there are any – I really am sorry about the aperiodic nature of the blog, the explantion of that would take too long to write and really isn’t important – but I do hope to do better in the very near future) readers of this impossibly unperiodic electronic space in the aether, have surely noticed my lack of optimism as well.  I think many of scientists who voice public optimism are privately much more “pragmatic” than their public utterances seem to imply and in some – few – cases I have heard about, almost suicidal from the depression and grief of being in the position of observing and documenting this aspect of what is now becoming known in the paleontological community as “The 6th Extinction.”  — The name derives from an examination of the fossil record, wherein there are 5 major extinction events that punctuate the history of life.  On the plus side, so far… life has always recovered and rediversified after these extinction events.  On the negative side, once the cause of the event has been removed, that recovery has always taken tens of millions of years.  Evolution is sure and certain – but to refill a lot of “vacant ecological niches” takes a lot of time.

The positive take is that the changes that occur over the next few decades that will happen should be “interesting.”

And young people today will get to see another interesting phenomenon, where 30 or 40 years from now, new students of marine biology will see this changed (and to my – by then-  long dead eyes) and depauperate, truly ghastly, world as “normal,” the status quo; rather like tourists who now go diving for the first time on (the pathetic algal covered ruins of) what used to be the coral reef at Cozumel or other Caribbean vacation spots, and think they are seeing a thriving coral reef. 

This is what Jeremy Jackson, now one of the “grand old researchers” of the Caribbean coral reefs refered to, in 1997, as “sliding baselines.”  (The underlined emphasis is mine, to emphasize that this has happened to me, too).   

J. B. C. Jackson (1997) Reefs since Columbus. Coral Reefs 16, Suppl.: S23-S32:

 “The problem is that everyone, scientists included, believes that the way things were when they first saw them is natural. However, modern reef ecology only began in the Caribbean, for example, in the late 1950s when enormous changes in coral reef ecosystems had already occurred. The same problem now extends on an even greater scale to the SCUBA diving public, with a whole new generation of sport divers who have never seen a “healthy” reef, even by the standards of the 1960s. Thus there is no public perception of the magnitude of our loss.

 Another insidious consequence of this “shifting baseline syndrome” is a growing ecomanagement culture that accepts the status quo, and fiddles with it under the mantle of experimental design and statistical rigor, without any clear frame of reference of what it is they are trying to manage or conserve.  These are the coral reef equivalents of European “hedgerow ecologists” arguing about the maintenance of diversity in the remnant tangle between fields where once there was only forest.”  

And now, on the cusp of 2011, it is ever so much worse.   We live in a sick world (in all senses of that phrase) run by an aggregration of dunces. 

On that happy note,

Cheers! ??

Diodogorgia Behavior

September 13th, 2010

I have been burning the proverbial solidified lipid light source at the proverbial points of illumination as of late, working on preparing my manuscript of my first Diodogorgia feeding behavior manuscript.  I am opting to try to place it in one of the most widely read journals; a journal with a very significant rejection rate.   This is a generalized journal and very widely read and it gets a lot of manuscripts submitted to it.  Having a finite – and relatively small –  size, this means most manuscripts are rejected, but fortunately, they are rejected “without” prejudice, so they can be submitted elsewhere, and most are and probably most get published.    So, I have the customary backup plan: “B,” for the almost certain rejection.  I have heard the odds of success are about 1 in 20, so…   I am trying to convince myself that my work will not get accepted and that I shouldn’t be too upset with that likely outcome.  

Oh, yeah… THAT will work. 

I want this thing to be published in this journal so badly I can taste it, so the inevitable rejection will hurt.   I am old enough, and my research is limited enough, that my odds of ever doing some more work that I would think would be of suffiicent importance to even try to place in such a journal again are so small as to be non-existant.  It will be this time, or never.  You may have noticed I haven’t mentioned the name of the journal, either.  Some readers can probalby guess which journal I am shooting for, but I don’t want to jinx the process by naming the journal. 

Jinxing…  What a funny thing, I am absolutely certain that my mentioning the journal’s name will have no effect on the process whatsoever – still, a primal part of my reptilian soul tells me not to mention what journal it is.   Sooner or later, I will let the readers of this blog in on my first choice of journals, probably after I have submitted it to the next choice. 

 At least, I should be able to turn the work around into a different manuscript for another journal relatively rapidly.   And I think my second choice – probably the specialized journal, Invertebrate Biology –  will accept my stuff without any qualms. 

For the last few days I have been making illustrations.  A number of these have been almagamations of images made from sequential video frames to show some of the behavioral processes of food capture or rejection.   And all of these have to be within a specific size category and most of them should be grayscale.  Even though I knew that such an outcome was likely, it is amazing how much information disappears along with the color.  I probably will submit both color and gray-scale versions of the same image.  Perhaps the reviewers will opt for one over the other.   However, color images cost a lot more, and that money comes from the author.

Argh… the cost issues are awful.  My readers – if there are any – in the scientific realm will realize this, but most other folks probalby don’t know that the costs for publication in these peer-reviewed journals are, at least on paper, borne by the authors.  Often there are other sources that will help an impoverished author like myself, but unlike the commercial press that I normally write for, not only is the submission and selection process anguishing, you get to pay for the whole thing – or at least part of it, just to make you feel worse, I suppose.

Well, at least most journals will publish accepted papers regardless of the author’s ability to pay.  Which is good, ’cause I have NO ability to pay.

I suppose it is time to get back to the process, so I will try to periodically keep you posted here.

Until next time,

Cheers,

Why?

July 22nd, 2010

It is time for my usual and periodic rant about the idiocies apparent in the coral reef aquarium hobby.  The particular thorn-in-the-paw that has set me off this time is one of the usual ones that have been beating around the scientific blogosphere over the last year or so; specifically, the lack of scientific literacy amongst the public – or in my case, the particular subset of the public that I sometimes interact with – the average aquarists I try to advise, or work with, or write for.  I have to throw in a caveat here; there are a fair number of very good aquarists, who can actually look up articles, and act upon what they read.  However, they are a small subset of the total number, and are the exceptions rather than the rule.  If you count yourself amongst this group, and have actually read something in the peer-reviewed literature, I hope the rest of this diatribe does not offend you.

I suppose I may be guilty of one on the mistakes I warn my readers about, that being making unwarranted generalizations.  Still…  It seems like trying to introduce common good husbandry based on scientific knowledge practices to the majorit of this group of folks is a useless task.

Nothing I propose is based on anything other than scientifically determined facts and good common sense, buttressed by those facts.  Most of the time following the suggestions would save a lot of money.  In all cases, it would result in healthier, longer-lived animals.  And after 15 years of doing this, I think I could count on the fingers of one hand the number of people who regularly correspond with me who seem to “get it.”  And, even though there are probably more, the fact of the low numbers is damned discouraging.

 The Aquarium Advice Form Of Gresham’s Law

 Gresham’s law in economics states that “Bad money drives out good.”  Basically, if two types of currency circulate simultaneously, and their exchange rates are governed by law, the artificially overvalued money tends to drive the other, artificially undervalued, or “the more valuable or good,” money out of circulation.  In the aquarium hobby world, it is the artificially overvalued advice, mostly advertisments, but some other advice as well, drives out or submerges the artificially undervalued advice, that based on scientific evidence.

One probably shouldn’t take this analogy too far, but it works pretty well on the short run.  Advice that is overvalued is that which is continually trumpeted by advertisements.  This advice is everywhere in short bursts, it is easily learned, and it is often repeated by people who don’t know how to test or evaluate it or probably more correctly, don’t care to test or evaluate it.  As we all know, continual exposure to a patent falsehood claimed to be true will result in that falsehood being accepted as the truth by the majority of the audience exposed to the repeated message.  This was discovered and explicitly stated by Joseph Goebbels, and has been exploited by every propagandist since then.  Of course, it was probably intuited by every natural-born scam artist since the first travelling caveman sold defective obsidian on his way through an ancient valley.  And it continues to be inuited today, and exists well in the advertisements aimed at aquarium hobbyists. 

The undervalued advice in my example, scientifically determined knowledge, requires the recipients to think about it and to implement it often in the face of an overwhelming amount of contrary advice.  That is hard to do, particularly when the recipients are today’s typical Americans who have never had any training in how to evaluate ideas or claims, and whose knowledge of science and the scientific method have been formed by shows such The X-Files

There are numerous examples of how idiotic advice seems to rise to the top in the aquarium hobby, but my favorites for today are the use of strontium and iodine as additives in aquaria.

Strontium is a known coral poison affecting calcium metabolism.  It has been demonstrated to reduce calcium transport across the coral’s surface membranes, and that is definitely not a good thing.  Fortunately, it doesn’t kill corals outright, and the the concentrations found in natural sea water, evolution has given corals the ability to detoxify it.  Still, adding it to an aquarium, to “boost” coral growth is not a really sterling example of the intelligence of the average reef aquarist.

Then there is the addition of iodine.  This material, often added in one of the many formulations called Lugol’s solution, is an essential material, in very small amounts.  The amounts necessary in a reef aquarium are so tiny as to be effectively unmeasurable.  Excess amounts of iodine are amazingly lethal.  Like many budding scientists who worked in freshwater systems, I learned about Lugol’s solution in my limnology classes, where it was used as a preservative. 

Yeah, that’s right.  A preservative, a material used to kill organisms and make them so toxic that nothing could eat them. 

Good stuff, to be adding to one’s aquarium, to be sure.  Especially as it is impossible to hobbyists test for iodine in aquaria as it has exceptionally complicated chemistry and no cheap test kits are available.  But that doesn’t matter, as you see, we all know that iodine is essential for crustaceans.  Particularly because it is necessary for crustacean molting.

Necessary for molting in crustaceans… You know, crustacean molting has been investigated in great detail by arthrophysiologists for as long as there have been scientific arthropod studies.  This is well over 100 years, and there is an amazing body of literature about the chemical aspects of molting in crustaceans.  Litereally, there are thousands of articles.  Turning to the Advanced Search in Google Scholar to get an estimate of the number of articles turned 11,800 hits, about 210 of these articles contain a mention of iodine.  A few of those discussing iodine inside the molting fluid and in the water outside the animal, along with all other ions the researcher could measure, but most of the mentions of iodine were as a component of various testing chemicals, not normally found in the animal but used as a reagent to indicate some other factor.

The sum total of articles mentioning iodine in any of its many forms as being necessary for molting was…   

Wait for it…

Zero.

One would think that if iodine were necessary for crustacean molting, there would be a plethora of articles describing its action.  There are for every other necessary chemical, such as 3,820 for phosphate, 3,210 for copper, 2,680 for iron, 2,520 sulfate, 4,080 for calcium.  Iodine zip…   Search engines turn up a lot of false positives, and depending on how one queries for iodine, hits can be found.  But, when those articles are examined, NONE of them discuss iodine as a necessity for molting. 

 Negative evidence is, of course, difficult to deal with.  The old saw, “Absence of evidence is not evidence of absence,” remains as sharp as ever.  Still, one would think that somewhere along the line, if iodine were a requirement for arthropod molting, some researcher over the last century would have found it.

Anecdotal stories from aquarists seems to indicate that iodine supplementation seems to cause some changes in molting.  My suspicion, my very strong suspicion, is that iodine poisons the molting process and causes premature molting.  Repeated iodine forced -molts result in premature death.   At the very least.  Now, I would love to be shown to be wrong.  But, I am not going to hold my breath waiting for such evidence to appear.

Below are some references about strontium in corals, they are all worth reading.  It is particularly enlightening to read the first two, and then the rest.  The first one tells how increasing strontium causes increased growth in corals.  The second one tells how that growth was an artifact of the experimental system.  The first one is used by incompetent aquarists to support their supposition about adding strontium.  These aquarists are incompetent because they didn’t read the next article.  And the subsequent ones.  

Of course if you want to read an article in the scientific peer-reviewed literature detailing with the necessity of iodine in crustacean molting.  You will have to find it.  I couldn’t.  

On the other hand, the aquarium version of Gresham’s law is alive and well, just check out any aquarium vendor and their online advice about iodine and strontium.

More later…

Cheers,

Strontium References:

Swart, P. K. 1980. The effect of seawater chemistry on the growth rates of some scleractinian corals. In: R. Tardent and P. Tardent (Editors). Developmental and Cellular Biology of Coelenterates. Proceedings of the Fourth International Coelenterate Symposium. Interlaken. pp. 203-208.
Swart, P. K. 1981. The strontium, magnesium and sodium composition of recent scleractinian coral skeletons as standards for paleoenvironmental analysis. Palaeogeogrraphy, Paleoclimatololy, Paleoecology. 34:115-136.

Chalker, B. E. 1981. Skeletogenesis in scleractinian corals: the transport and deposition of strontium and calcium. In: S.C. Skoryna (Ed.) Handbook of Stable Strontium. Plenum Press. New York, pp. 47 63.
Ip, Y. K. and P. Krishnaveni. 1991. Incorporation of strontium (90Sr2+) into the skeleton of the hermatypic coral Galaxea fascicularis. Journal of Experimental Zoology. 258:273-276.
Wright, O. P. and A. T. Marshall. 1991. Calcium transport across the isolated oral epithelium of scleractinian corals. Coral Reefs. 10:37-40.
Greegor, R. B., N. E. Pingitore, Jr. and F. W. Lytle. 1997. Strontianite in coral skeletal aragonite. Science. 275:1452-1454.

Good Stuff

July 3rd, 2010

I have been going from a bare bones, sorta, tank back to something that is an approximation of a natural system.  My aquarium is nothing I would call a reef tank a the present time, more like the emulation of a habitat someplace near a reef.  In other words, no stony corals, yet.  And probably not for a long time.  For the last couple of years my system has mostly been focused on maintaining my research animals.  And it had been an adequate system, as far as it went, it just wasn’t the most aesthetic aquarium of all times.  In fact, it was pretty much the other extreme.  To a large extent, this condition was due to my health problems, which finally seem to be fading a bit.  I simply didn’t have the time to maintain it properly.

So…

I have been in the process of converting my aquarium into a more attractive system designed to maintain and support my research beasties of the present, my Diodogorgia colonies.  Now, like any good scientist, I don’t want to spend any more time than is absolutely necessary in this exercise.  I am NOT one of those aquarium hobbyists who spends all waking hours puttering around his/her system.  Nope.  I want to put the animals in the system, and sit back and enjoy it as I can, relaxing… Not working.

My research has shown that Diodogorgia colonies need strong, and more-or-less laminar currents to feed well.  It just can’t capture prey very well in either particularly slow currents or stagnant situations, nor in strong currents that are irregular, the type of water flow generated by so-called wavemakers, and oscillators.  So I have created a Diodogorgia gully along one side of my system with the wall of the aquarium being one side, and live rock being the other.   At one end of the aquarium, I have three relatively powerful powerheads to create the current.  I can’t, in this situation, use propeller type pumps, because the ones I have create a noise in the tank that irritates my spouse – apparently anywhere in the house (and, it is a noise I can’t hear, sigh…)  .  So…  a compromise, but it seem to be working so far.

Yesterday’s event of notice was the arrival of a shipment of sand bed and “maintenance” critters from Indo-Pacific Sea Farms.  I been periodically purchasing this type of critter from this vendor for over ten years, and other than the fact that some of the animals are misidentified (more about that below), I have nothing but good things to say about the operation.  The animals arrive in good order, ALWAYS.  The animals arrive in labeled bags, ALWAYS.  And the animals are reasonably priced, ALWAYS.   

Yesterday, I got a shipment of “bristle worms” – amphinomids or fire worms, the classic scavengers, some of their “Mama Mia” worms – these are cirratulid worms, not terebellids as it states on the webpage.  See this online article to tell the diffence between the two types of worms.  Nobody in the hobby, as near as I can tell, actually sells terebellids, but many folks misidentify cirratulids as terebellids.  Folks,  the presence of a lot of tentacles isn’t the sole diagnostic characteristic for a terebellid, those tentacles have to arise from a specific body region and the whole worm has to have the proper morphology.   Similarly with the cirratulids.  These two types of worms are NOT hard to tell apart. 

This is one of the cirratulids I got from IPSF. They do well in a good sand bed and are great detritivores.

I also got some mini-stars, small brittle stars, and some of the the “miracle mud,” some sediment containing real microscopic sediment critters, as a recharge for my sand bed.  This latter stuff is what live sand should be when it is sold, but other than IPSF, I don’t know of any vendor that actually sells it.

Finally, I finished off my order with some good grazing snails, three of the Trochus IPSF sells, and an order of grazing columbellids.  Although IPSF calls the latter Strombus maculata, they are clearly not a strombid.  However, that misidentification doesn’t get in the way of their grazing abilities, which are truly awesome.  These little snails are probably a species of Euplica, but that is really not important.  And here is an article that discusses the differences between the columbellids and the conchs (= strombids).  Again, they are not hard to tell apart, and the columbellids are really the best grazing snails in the business; additionally, they survive far better in reef tanks than do strombids.

This is one of the columbellids added to my system. See the linked article for differences between these animals and conchs (strombid snails).

Finally, and the thing that makes IPSF a REALLY great place to buy from, is that all of this stuff is aquacultured.  They raise it all.  YES!!!!  A marine aquarium animal vendor that is doing business like it should be done.   I had a heck of a good time yesterday adding all of these animals and a few other things, some algae, besides to my tank.

Until later,

Cheers.

Macroalgae(s)

July 2nd, 2010

Any recent visitor to my “expert” forum on the Marine Depot site may have noticed a new posted note about feeding – and about the language.  More to the point, not just about the language, but about the use of words that seem on their way to becoming ubiquitous amongst reef aquarists.  These are  the “invented” words that form from unfamiliar terms, such as “algae,” giving rise to algaes (sic) by itself, or in the combined forms:  micro- and macro-algaes (sic).  The case that pushed me over the edge this particular time was zooplanktons (sic), supposedly – I think – as a plural word for a zooplankter, a single zooplankton entity.   However, I will point out, I couldn’t discern from the sentence where it was used, what the writer meant.   Arrgh!!!

Ah, isn’t illiteracy wonderful? 

The marine aquarium hobby is an expensive undertaking, this generally means that two types of people become hobbyists:  those who can easily afford it, and those whose interest in the animals/hobby is so great that they make all sorts of sacrifices to participate.  As one might expect there are relatively few of the latter folks, although in many cases, when one can identify them, they often are amongst the more knowledgeable of hobbyists.  The point of this statement is that to be able to afford such a hobby, one often has to have a well-paying job, and following this train of thought to full derailment, such jobs are often domain of people that have a so-called “good” education. 

So… why are so many of these people illiterate?   

For that is what the misuse of the these simple terms implies.  Either the people have not been exposed to fact that the plurals of many words are not made by simply plopping an “s” down at the end of the word, or they are not aware of such strange tools as “dictionaries.”   I suppose the problem is that these folks read or hear the term and become aware of some sort of meaning for it from the context wherein they find it.  And, away we gooooo……

Probably the word in this regard that captures most people is “algae.”  People see the word and kinda, sorta, somehow get a warm, fuzzy, or cold, slimy, idea of what algae means; all the time not realizing that algae is a plural term.  More than likely this is because the original user of the word, hasn’t a clue about the word, either. 

It is really interesting, and more than a little disheartening, to read something one of these people writes and to realize that they don’t have a frigging clue as to what any single alga is.  Let alone what many algae are.  They have no conception that algae are not plants – but, hey, don’t try to pin them down on what a plant is, either.   You really don’t want to know what they think it is.

The marine coral reef aquarium hobby is by some sort of necessity technical.  It has to be, there are no common names for many of the organisms, and most of the techniques for maintain the organisms verge on being complicated culture methods requiring more than a little bit of scientific or technical background.  While there are many aquarists who are very well versed in the sciences or engineering, there are unfortunately quite a large number of wannabes who just don’t have a clue about what they need to do to keep their organisms alive, or for that matter what their organisms even are (oh, they may use a name, they just don’t realize what the name implies).  The sad part of all of this is that they, in most cases, already have the organisms as they have purchased some critters and some equipment because of some smooth-talking salesperson.   Generally, the budding aquarist seems to think they have something like a gold fish (hey, the fish they have is golden… that make it a gold fish, right?).  And the equipment they purchase, instead of being a set of expensive devices specifically tailored toward keeping these strange creatures alive, is simply a series of “black boxes” of unknown and unknowable function.  All our aquarist has to do is to follow some simple instructions, and their animals will be thriving.

Sigh.  It is hard to tell who is more to blame here;  the clueless individual or the mercenary salesman.

One would like to think that people don’t view these beautiful living things as disposable, but all too many of them have the asinine  philosophy that animals are put on Earth for man’s benefit, another unfortunate piece of garbage thought spawned by our dominant religions superstitions.  In this case,  who cares if one doesn’t know how to take care of the animals properly, it is no big deal.  One would like to think that people would try to learn about keeping these organisms before they purchase them – and to the credit of many, they do.  But far too many don’t.  These are the people who can’t read enough to know that they don’t know what one alga does, let alone what many algae mean in the context of a marine aquarium. 

And so it goes, and questions will arise about microalgaes, and phytoplanktons, and…

I will beat my head against the wall, ’cause it will feel SOOOO good when I stop.

Until later,

Cheers,

Pre-Iridiana, A Found World

April 25th, 2010

Early in the last century Sir Arthur Conan Doyle wrote about Professor Challenger, a “scientist” who found bits and snatches of the world of dinosaurs still living, most famously, on plateaux in the Amazonian jungle. There he found living pterosaurs, dinosaurs,  and all manners of strange and wonderfully monstrous animals. Alas – maybe – the animals that Doyle wrote about vanished from the living world in the aftermath of an impact of a rather small asteroid with the Earth, some 65.5 million years ago. During the vast span of intervening years, the Earth has changed. Very dramatically!! The world of the dinosaurs really was not the world of man, but it has only been in the last couple of decades have we been truly able to realize how different these two worlds were from one another.

Until recently, except for the foolishness of the massive floods and perfect gardens found in some of the religious mythologies of the world, if people thought about what the world was like in the distant past, they visualized it pretty much as the world they saw around themselves.   As a scientific viewpoint developed in the nineteenth century, particularly within the basic science of geology, there were many acrimonious debates between those individuals who contended that all changes were gradual and based on the same or similar processes as were seen in action today, the uniformitarianists, and the catastrophists, who contended that many calamitous changes, mostly floods of a truly biblical nature, radically altered and changed both the landscape and the life on it. By the beginning of the 20th century, the catastrophists were pretty much considered to be all wet, and uniformitarianism carried the day, the week, the month, the year, the decade, the generation… but not quite the century.

By the beginning of the 21st century, thanks to some brilliant insight, and a lot of hard work, it had become clear that although the world’s environments had stayed rather consistent for long periods, there have been times of drastic change, after which literally everything, from climate to biota, changed. For most folks, the most notable of those drastic changes was the one that ended the domination of the world’s bioata by the larger non-avian dinosaurs, the Cretaceous epoch, about 65.5 million years ago. Although, by far and away, not the largest of these mass extinction events,  the devestating changes triggered by the impact of a small asteroid off shore of the northern presumptive Yucatan peninsula were damaging enough;  resulting in wholesale changes in the Earth’s biota, virtually every large terrestrial animal species went extinct, along with many marine species.  Subsequent changes in the Earth’s climate resulted in today’s world; a much different globe than that the larger dinosaurs dominated.

Although this event, the Cretaceous/Tertiary Mass Extinction, closed the door on the non-avian dinosaurs, it allowed mammals, more-or-less by default, to adaptively radiate and come to dominate the world.  Nonetheless, the extinction event, while it changed the biota, did not wipe away the evidence of the world that had existed.  That world holds, for many people, particularly evolutionarily oriented biologists, a fascination due the awesomely different biosphere that was present.  

About a month ago, I received as a gift, the book titled, The Cretaceous World, by Peter Skeleton and his coauthors. Over the last few weeks I have been enjoying learning about that long gone world. Very well-written, and exceptionally well-illustrated, the book is designed as a text, but unlike many texts, this one is as alive as the inhabitants of the world it describes are not. Pulling together geological, oceanographic, and biological data, much of it gathered in the last few years, the authors create a world that is awesome in its differences from the present one. From discussing in detail forests at the latitude of Pt. Barrow, Alaska, to describing ferocious storms in the central Tethys seaway, along with the immense deserts of the equatorial latitudes, the authors take the reader on a memorable mental tour of a long-lost world.

I have so enjoyed this book that I want to tell people about it.  In a way, it is the most wonderful type of science fiction, although I am certain the authors would not appreciate that description.  However, they describe in detail a world that changed over the 80 million year history of the Cretaceous, a world based on very hard, and very good science, and have assisted the reader to clothe this world with their mental images.  We really will never know what the Cretaceous world looked like, nor will we ever find out much about the vast majority of the animals that lived there (because they were invertebrates and didn’t fossilize), but we have a good basis for knowing the world itself.  So, what we see in our mind’s eye may be “science fictional,” but it is the hardest of science fiction, that based on and consistent with all the facts.  This world would not be the benign, kind and friendly world of  Jurassic Park.  Humans in the Cretaceous would find the climate oppressive, the flora unfamiliar, the oceans utterly strange, and full of dangerous reptilian predators, although those are not discussed in the book.  And, in general, the megafauna positively frightening and exceedingly dangerous; Cretaceous Park would be a great place for a well-prepared scientist to visit, but you really wouldn’t want to live there. 

The animal life, however interesting, is not the center of the discussion.  While putting the story together for their students, the authors have really given the rest of us a rare glimpse of an alien World, from a geologist’s perspective.   We become aware of the almost familiar orientation of the continents,  but the huge oceanic areas render the land masses of those continents much smaller than what is experienced today.  While the continents are tectonically moving, they haven’t – yet – encountered each other in the massive collisions that have characterized the last 50 million years.  There are not a lot of impressive mountains.  Lots of hills, to be sure, but nothing like the Himalayan plateau, and the Alps are in the future as well.   Coral reefs are the dream of the cnidarians’ future, but – Wow!, this is the world of the Clamrades!  There are huge expances of clam beds comprised of, in many cases, huge clams.  What most geologists don’t really seem to flash on, the author’s of this tome missed it as well, is the amount of biomass that must have existed planktonically in the shallow seas.  These seas were not the clear blue seas of today’s coral reefs, they were gorpy, green, and thick with life.  The huge carbonate “platforms” of the Cretaceous had to feed on something, and clams have a lot higher metabolic rate than do corals. 

And the temperatures!  Baby, it’s hot out there!!!  Diving in the shallow equatorial seas would kill a scuba diver.  There would be no way to dump the body’s excess heat, and any exertion at all would be lethal.  Rather like diving in the hottest extremes of the Persian Gulf today, one could not spend a lot of time in those oceans.  One probably wouldn’t want to, though, as humans could have been considered to a good snack for some of the mosasaurs and other swimming arrays of teeth; LARGE swimming arrays of teeth, that dominated those seas. 

The  Cretaceous world that the authors describe in detail, really for the first time, is in effect, like an extrasolar world, only one that is 65.5 million light years away in space and time.  This world would be a great star of documentaries, although you couldn’t pay me enough to go film the action; nonetheless, I would love to see it.

Enjoy the book and learn about a wholly new place, the Olde Earth.

Until later, 

Cheers!