31 August 2009

Whole lotta bones

Yesterday we were at the National Museum of Natural History in D.C. and looked at the interesting exhibition Written in Bone. The exhibition is about the forensic investigations of human skeletons and how forensic techniques have been applied to the bones of the 17th century English colonists in Jamestown, Virginia and St. Mary’s City, Maryland.

Written in Bone was quite informative and, as you can imagine, there were lots and lots of bones on display.

This is the skull of a late 20s man who had a couple of "pipe facets" thru his front teeth where he had habitually kept his pipe. I marked the one on the right side of his mouth with an orange arrow.

PipeFacet

This edentulous (toothless) skull belonged to a 73-year old man who obviously didn’t take good care of his teeth. Not only had he lost all of his teeth but the underlying sockets as well. He is stated to have been a "denture wearer". Obviously, a recent skull since they didn't have dentures back in the 1600s, did they?

EdentulouSkull

Here is the skeleton of a pre-term fetus. Look at the size of that skull in proportion to the rest of the body.

PretermFetus

This poor fellow took a bullet right thru his forehead. He must died instantly, but his skull survived to tell a story. This may also be a recent skull.

GunshotWound

And finally, here is the late anthropologist Grover Krantz (1931-2002) and his dog Clyde. Krantz spent (wasted?) his career at Washington State University searching for Bigfoot and never found it, of course.

GroverKrantz

Read the story behind this special display here.

29 August 2009

It was 30 years ago today

On this day in 1979 I arrived in the U.S.

I don’t have any tickets, receipts, pictures or other documents left from that day. But I still have my little, now yellowed, notebook.

My primary concern for the first few months seems to have been not to overspend my meager TA stipend. So I was keeping track of my daily spendings to make sure my daily average was at or below what I could afford in a month. It's amazing how little food cost back then. On 10 September, I had 2 hotdogs and a coke for lunch for $1.30. Dessert was an additional $0.25. I didn't specify what it was. A cupcake? A chocolate bar?

The school wasn't open yet and I spent most days exploring Philadelphia, the closest large city. On 2 September, I made my 1st major discovery in the U.S.: a bookstore in Philly. It was the Encore Books (are they still around?) and bought a cheap book. There is a sketch of the location of the bookstore in my notebook with the landmarks written in Turkish or English.

EncoreBooks
If you are familiar with downtown Philly, you can probably recognize the streets around Chestnut St. fışkıran su: fountain spraying water; trene inen merdiven: stairs to the train; köşede restaurant: restaurant in the corner; pazar da açık: open also on Sundays.

I was so impressed by the abundance and the variety of books that I resolved then and there that I was staying in this country.

Here I am 30 years later.

28 August 2009

How a snail moves - Part 2

Biological evolution has not produced wheel-like organs that exhibit a continuously looping movement while remaining in contact with the ground. However, an organism can move continuously even if it's not on wheels and even if its foot—the part of its body in contact with the ground—consists of units that take turns moving sequentially. This type of movement has evolved in gastropods.

Part 1 of this series introduced the observation that during the locomotion of a snail (or a slug) the movement of a given point on the sole of the snail is not continuous, but intermittent, even though the overall movement of the snail is continuous. Here is another demonstration of the same phenomenon, this time using data from my files. Because these data are not published yet, I will not reveal the species; it will suffice to note that it's one of those snails that has a snout anatomically separate from its foot.

HowSnailMoves2

Notice how the horizontal movement of a selected point on the sole is intermittent, while that of the snout is more or less continuous*.

Here is a diagram to explain how a snail accomplishes this (that thing actually looks like slug, but it doesn't matter).

HowSnailMoves3

For simplicity, assume that the sole of the snail consists of only 3 units (A, B and C) that move sequentially. First, A moves forward, while B and C are at rest. Then, B moves forward, while A and C are at rest and so on. The trick is that the upper body is attached to the foot in such a way that it must move forward every time one of the units making up the sole moves forward. The results is that the progression of the body, for example, the front of it (thin blue line) is continuous, even though the progression of any one unit in the sole, for example, A (thin red line) is intermittent.

In a real gastropod, there is a wave-like motion within the sole that usually starts at the tip of the tail and moves forward to the head. Only that portion of the sole where the wave happens to be at a given instance moves forward, while the rest of the sole remains stationary on the substrate. However, the overall results is that the snail continuously moves forward.

That this is the general mechanism of gastropod locomotion was deduced a long time ago. For example, Parker wrote in 1911:
At first thought it might seem that such a wave movement could not produce so uniform a motion as snails show, but it must be remembered that the uniformity of this movement is seen only in parts of the animal some distance from the foot. On the foot itself the operation is alternate movement and rest, which becomes more and more continuous motion as points on the body more and more distant from the foot are reached. The locomotion is in many fundamental respects like that of the human being. In our locomotion each foot is alternately at rest and in motion and yet distant parts of our body, like the head, show a motion which in comparison with that of our feet is almost continuously uniform.
Of course, there are many details and variations among different gastropod taxa that still need to be worked out.

I will return to this subject.



*The raw data consist of sequential photographs taken over several seconds. The horizontal axis of the graph is simply the image number. The horizontal displacement (vertical axis) is in arbitrary units, because no scale was included in the photographs.

G. H. Parker. 1911. The mechanism of locomotion in gastropods.
Journal of Morphology, 22:155-170. pdf available at Biodiversity Heritage Library

27 August 2009

How a snail moves - Part 1

LissmannFig1
Somewhat confusingly, the vertical axis is the horizontal displacement against time on the horizontal axis.

This graph is from Lissmann (1945). It shows the horizontal displacement in time of a mucus gland on the sole of a Helix pomatia, a land snail, that was crawling up on a vertical glass plate.

The most significant piece of information to be gained from this graph is that the movement of a point, any point, on the sole of a snail is not continuous, but intermittent. That is the case even though the overall movement of the snail is continuous.

Part 2


H. W. LISSMANN. 1945. The Mechanism of Locomotion in Gastropod Molluscs: I. Kinematics
J. Exp. Biol. 21:58-69. pdf

26 August 2009

Slug eating a mushroom

MegapalliferaOnMushroom

Nothing earth-shaking here; just a slug, a Megapallifera mutabilis, eating some sort of fungus that was growing on a dead tree. Many species of slugs (and snails) like fungi, but I don't remember if I had seen a Megapallifera eating one before.

25 August 2009

American chestnut tree with chestnut blight

The American chestnut (Castanea dentata) was once one of the dominant trees of eastern North American forests. A bark fungus (Cryphonectria parasitica), the causative agent of a disease known as chestnut blight and accidentally introduced into North America from Asia early in the 20th century, almost caused the tree become extinct. The species still survives, however, and there are now efforts to breed trees more resistant to the killer fungus.

I photographed this American chestnut tree suffering from blight in Seneca Creek State Park in Gaithersburg, Maryland about 10 days ago.

AmericanChestnut1

This is what the sign says.

AmeircanChestnut2

Apparently, chestnut blight kills the main trunk, but the roots survive and new shoots often sprout from around the roots. That was exactly what was happening in this case.

24 August 2009

Who discovered that pulmonate snails and slugs are hermaphrodites?

This is one of those burning questions that's been occupying the minds of the most esteemed historians since I asked it way back in 2005 in this post. In the same post, I also asked, rather naively, if Lamarck had been the first person to find out that pulmonates were hermaphrodites.

Now I know that the hermaphroditism of pulmonates had been determined long before Lamarck was active in the early 19th century. For example, James Barbut wrote in his 1783 book The genera Vermium exemplified by various specimens of the animals contained in the orders of the Intestina et Mollusca Linnaei that the slug Arion ater "is an [sic] hermaphrodite, both sexes being in each individual, and both in the coitus impregnate, and are impregnated, at the same time."

In fact, the historical discovery appears to have taken place more than a hundred years earlier sometime around 1670. I have narrowed the responsible person down to 3 names: the Swiss Johann Jacob Harder, the Dutch Jan Swammerdam and the English John Ray. Within a period of less than 20 years, each man figured it out, probably independently, that pulmonate gastropods were hermaphrodites.

But who was the 1st one to publish his results? You may have to wait a while before I figure that out and reveal it here.

23 August 2009

Jug Bridge Memorial

The Jug Bridge over the Monocacy River to the east of Frederick, Maryland was built by Leo Harbaugh in 1808. The bridge was named after the stone structure shaped like a "demijohn" Harbaugh placed on the east end of the bridge. This "engineering marvel" collapsed nevertheless in 1942.

A new bridge was built near the ruins of the old bridge and the demijohn was subsequently moved to a very small park not too far from the river where it now stands.

JugBridge1

The names of the principal workers were chiseled into the stone near the top of the jug and are still legible.

JugBridge2

The French general Marquis de Lafayette crossed the bridge in 1824 during his tour of the U.S. 50 years after the Revolutionary War. A plaque commemorating this event was placed by the bridge in 1926. It too has been preserved in the park.

JugBridge3

The Jug Bridge Memorial Park is sequestered between I70, MD144 and Bowmans Farm Road outside of Frederick. Here is an image from Google Earth showing the location of the park (red arrow).

JugBridge4

21 August 2009

Importance of behavioral adaptations in animal evolution

Are morphological adaptations sufficient to explain the varieties of lifestyles of all the extant animals? No. Behavioral adaptations are equally significant, but they almost always get second billing, usually far below morphological adaptations.

Although behavioral traits may be more difficult to quantify than morphological traits, they are probably as variable as morphological traits. If a variable behavioral trait has a genetic basis, then it too will be subject to selection.

Careful observations of any animal, especially in its natural habitat, will make it clear that the contributions of behavior and morphology are not necessarily separable during the day to day survival of an animal. Therefore, behavioral and morphological traits must have evolved concurrently.

Consider the hypothetical case of a land bird that doesn't normally go into water, for example, a chicken, that was born with webbed feet like those of a typical water bird*. I suppose such a morphological anomaly could result from a mutation. However, it would be highly unlikely that such a chicken would behave like a duck, go into a lake, duck its head under the water and attempt to pick up edible things from the bottom.

KastamonuGeese
Birds with webbed feet acting funny

All of the morphological adaptations of ducks (and those of other water birds) are essential, but not sufficient, for their survival in the water. They also need behavioral adaptations.

Disclaimer: I jotted these preliminary ideas down late last night shortly before I fell asleep. If they are not entirely coherent, take into account the late-night factor and go easy with your criticism.


*On the Internet, there is, in fact, a news report about a chicken with webbed feet as well as one about a duck with chicken feet, but they both lack details and could well have been hoaxes.

20 August 2009

What?

I was in graduate school, about 24 years old, when I first realized that my hearing was less than perfect. One spring afternoon I was sitting near an open window in my room and studying for an exam. I noticed that if I turned my left ear towards the window, I could hear the birds chirping outside, but that if my right ear was turned that way, it was all quiet. Of course, this wasn't such a bad thing when you were trying to ignore the external noise and concentrate on some boring subject.

Luckily, my hearing, or the lack thereof, has worsened slowly and only recently reached a point where it started to become a minor social handicap. So today, I went to see an ear, nose and throat specialist. The results of the standard hearing tests were pretty much what I had been suspecting.

audiogram

My left ear hears barely at the normal level (the dark horizontal line), while the right ear can hear only those sounds at least ~25 decibels above it.

Although my asymmetric hearing deficiency is most likely a congenital problem—that was nevertheless almost undetectable until my early 20s—the doctor wants to do one more test to rule out a benign tumor. After that I will be getting a hearing aid.

Until then, if you run into me in the street, try to stand on my left and speak a bit louder than usual.

19 August 2009

A couple of frogs and a book about them

Yesterday, these frogs were quite common in the woods along the Monocacy River near Frederick, Maryland. The adults were under logs and tree bark on the ground, while smaller ones (probably the same species) were hopping around.

EasternAmericanToad1

Here is another one.

EasternAmericanToad2

I am identifying them as the eastern American toad (Bufo americanus). According to White & White (Amphibians and Reptiles of Delmarva, 2002), that species differs from the similar Fowler's toad in having the "cranial crests not touching parotoid glands or connected by a short spur". The arrow in the picture below is pointing at the spur connecting the cranial crest behind the right eye to the swollen parotoid gland.

EasternAmericanToad3

Here is the book about frogs and other amphibians: G. Kingsley Noble's The Biology of the Amphibia, originally published in 1931; this is the 1954 Dover edition.

BiologyAmphibia

I bought it at the used bookstore for $2 a few days ago. The previous owner was Wolfgang P. J. Dittus. Does anybody know who he was? Not that I intend to return the book to him. Obviously, he didn't want it or need it anymore. In fact, the book is so clean and neat that he may have never used it.

WolfgangDittus

Now, notice how puffy the frogs were when I photographed them. This is what Noble said in his book about this behavior, which is common to many species of frogs: "The inflation increases the size of the body and removes all wrinkles from the skin. Smooth, swollen frogs are both difficult to seize and difficult to swallow." Nice behavioral adaptation that presumably serves as a defense mechanism against frog swallowing predators, snakes, for example. Their habit of remaining motionless—even in the presence of a nearby human finger providing a scale—is undoubtedly another behavioral adaptation.

18 August 2009

Snails and ice cream (and beer)

From now on, every field trip on a hot summer day shall have an ice cream break.

Snails&Icecream

And end with a cold bottle of beer.

heineken

It doesn't have to be Heineken, of course, but nothing wimpy, please.

17 August 2009

Where do dead birds go? — Part 48B

Continuing our series on what happens to birds after they die. The previous posts were here, here and here.

And here is a bird that lost its head and couldn't go anywhere.

DelisleDeadBird

I photographed this one 10 days ago near the Delisle River in Quebec, Canada. There were geese and ducks and one gull in the river, busily feeding themselves. But I can't tell what species this dead one is. As judged by the size of my shoe, it was a relatively large bird. A duck perhaps?

So, once again, if you do a lot of walking around and pay attention to what's on the ground, you are likely to see plenty of dead birds, in addition to snail shells.

16 August 2009

Cepaea nemoralis in North America

Our recent discovery of the European land snail Cepaea nemoralis in Maryland (see the posts here and here) has aroused my interest in this species. Since we will write a manuscript eventually, I am now in the process of collecting the relevant literature and learning about not only the history of C. nemoralis in North America, but also its biology.

The earliest recorded introduction of C. nemoralis in North America was that of W. G. Binney in 1857 in Burlington, New Jersey. This information is in the 2nd edition of Report on the Invertebrata of Massachusetts (available here). The 1st edition of that report, prepared by A. A. Gould, was published in 1841. Gould died in 1866 while preparing the 2nd edition and Binney took over the project as the editor. The 2nd edition was published in 1870 with the names of both Gould and Binney. Under Helix hortensis (=C. hortensis), there is this statement concerning Helix nemoralis (=C. nemoralis): "In 1857 I imported some hundred specimens from near Sheffield, England, and freed them in my garden at Burlington, New Jersey. They have thriven well and increased with great rapidity, so that now (1869) the whole town is full of them." Since Gould died in 1866, Binney must have written that first-person narrative.

Although Reed (1964) cited two 19th century records of C. nemoralis from Canada, those may have been based on specimens of the similar C. hortensis. The earliest reliable record of the species from Canada is probably that from Owen Sound, Ontario given by Pilsbry (1928). Those snails had apparently originated in France.

There have been other intentional and unintentional introductions of C. nemoralis over the years (Reed 1964). New colonies are occasionally discovered in places where the snail was not seen before. For example, see Whitson (2005) for the account of a colony recently discovered in Kenton County, Kentucky (no date given in the paper). C. nemoralis may be slowly dispersing throughout North America.

I will leave the discussion of the evolutionary aspects of the biology of C. nemoralis for a future post.


Pilsbry, H.A. 1928. Helix nemoralis L. in Ontario. Nautilus 42:42-43.
Reed, C.F. 1964. Cepaea nemoralis (Linn.) in eastern North America.
Sterkiana 16:11-18.
Whitson, M. 2005.
Cepaea nemoralis (Gastropoda, Helicidae): The Invited Invader. Journal of the Kentucky Academy of Science 66:82-88.

14 August 2009

AUTO INGS ON BOD WORK

MontrealStore

Defunct car repair shop in Montreal.

13 August 2009

Where are all the malacologists?

About 10 days ago, Christopher Taylor over at Catalogue of Organisms had a post about the terrestrial gastropod superfamily Gastrodontoidea. While introducing his taxon, Christopher took the opportunity to complain about the lack of basic malacological information, besides photographs, on the internet. Specifically, he was referring to the sort of information one could use to understand a little bit of the basic biology and the taxonomy of a given taxon.

For most mollusk groups that sort of information is indeed lacking. The mollusk taxon that is best represented on the Internet is probably the Opisthobranchia, the sea slugs. Considering that the Mollusca is the 2nd most speciose phylum, after the Arthropoda, one would think that there would be proportionately more information about them on the Information Highway.

In a comment I left after the said post, I suggested that one problem for the mollusks’ lack of adequate representation may be that there aren't that many malacologists around. Another commenter, Susan J. Hewitt, a regular reader of this blog, agreed with me and added that “most of the professionals...are way too busy with career-building (think resume and publications list) to spend time putting info onto the 'net”. That is probably true, not that there is anything wrong with career-building.

Earlier today, while looking up some papers in The Nautilus from 1971, I chanced upon a short article by the late malacologist Dee Dundee titled United States research trends in malacology (85:67-69; pdf of vol 85). Dundee had searched 10 major journals published in the U.S. during the period 1900-1969 and grouped the papers on mollusks into broad categories. According to her findings, until the late 1960s the majority of the publications dealt with taxonomy and distribution, while papers on physiology, behavior and reproduction of mollusks hardly ever reached the 5% level. I don’t think things have changed much since then.

But what really attracted my attention was her following comment:

From this search it was found that research was being done over the last ten years by less than 100 workers, a remarkable few in view of the fact that mollusks represent the second largest group of living animals.
This was almost 40 years ago. The total number of practicing malacologists in the U.S. doesn’t seem to have increased much since then. The annual meetings of the American Malacological Society routinely have only about 100 attendants with perhaps a quarter or more of those being graduate students. Of course, not every malacologist is expected to go to the AMS meetings. In fact, the AMS directory lists ~260 members, but not all of them are in the U.S. The total number of practicing malacologists in the U.S., however one may define that, may only be about 150. Thus, when the increase in the U.S. population since 1970 is taken into account, the proportion of the practicing malacologists seems to have remained about the same.

The real question boils down to Why are there so few malacologists? Is it because jobs in malacology are hard to come by? What about the practicing amateurs? I don’t know the answers.

12 August 2009

2700-year old Turkish tablets? Now that’s unbelievable

AncientTurkishTablets

ScienceDaily reports the discovery of “Ancient Turkish Tablets” in a 2,700 year old “Turkish Temple”. Another fine example of sloppy journalism and careless editing.

In reality, they are cuneiform tablets from a Neo-Hittite temple found in present day Turkey. Despite the silly and persistent claims of certain groups in Turkey, the Hittites were not a Turkic tribe. Not that ScienceDaily implied that.

ScienceDaily was the site that brought us the news about a portrait of Shakespeare under the "Fossils & Ruins" category (see this post).

11 August 2009

That was a cooked snail on my fork

SnailEating

And yes, I did eat it, my exaggerated pose notwithstanding. This was last Friday night when we had dinner with a large group of relatives and friends in a Montreal restaurant. The snail was kindly offered to me by Etyen Mahçupyan, visible behind me in the picture, from the plate of Snails Provençale with Pesto he had ordered as an appetizer.

What did the snail taste like? Why, like pesto, of course. I don't know if snails have an intrinsic flavor. I think the flavor normally attributed to them is simply the combined flavors of the spices and other ingredients they are cooked with. Correct me if I am wrong.

10 August 2009

Lunch options at Montreal Trudeau Airport

MontrealTrudeau

Bon appétit!

07 August 2009

On the way to Canada again

By the time this post appears today, I will be in Montreal. My niece Simla is getting married. Actually, she got married just a little bit more than a year ago, but there never was a wedding. This is going to be it. One long party on Saturday.

Last year's trip netted Pupilla muscorum and some Discus species whose identity was the source of a minor dispute. I will try to get more specimens to hopefully settle the issue.

Last year I traveled as a Professor, the year before I had myself knighted. This year I am a "Mstr".

MstrOrstan

Presumably, that stands for "master". But master of what? Master of the Universe? Master of Ceremonies? Or just plain old master baiter?

I may let you know when I return on Monday.

06 August 2009

What do philomycid slugs and poison ivy have in common?

They have similar worldwide distribution patterns.

The members of the slug family Philomycidae are found in eastern North America and southeast Asia. Here is their distribution range.

PhilomycidaeDist
Verbreitungskarte der Philomyciden, the distribution map of the Philomycidae from Hoffmann (1924). Keep in mind that the taxonomy and the known ranges of the philomycid species may have since changed, but the overall distribution is probably still the same.

And here is the distribution range of the genus Toxicodendron.


From The Poisoned Weed by Donald G. Crosby (2004).

Toxicodendron radicans is the poison ivy. There are several subspecies of T. radicans in eastern North America and 2 subspecies in China, Taiwan and the Kurile Islands.

Is it a coincidence that a family of animals and a species of plants have roughly the same distribution ranges each characterized by 2 widely separated areas?

This peculiarity is not limited to the Philomycidae and Toxicodendron radicans. There are some other groups of animals and plants with similar shared ranges in eastern North America and Southwest Asia.


*Hoffmann, H. 1924. Zur Anatomie und Systematik der Philomyciden. Jenaische Zeitschrift für Naturwissenschaft 60: 364-396.

05 August 2009

No job openings in malacology today

MalacologyJob1

Not that I am looking for a job, but I was curious.

MalacologyJob2

04 August 2009

Tuna stocks are not collapsing unless they are

In the 1 August issue of the New Scientist, there is an essay by a James Joseph who is stated to be on the board of directors of the International Seafood Sustainability Foundation. Mr. Joseph writes:

So contrary to what you might have been led to believe, tuna stocks are largely in good shape.
But 5 short paragraphs later, he adds this qualifier:
Excluding bluefin, tuna fisheries are close to peak productivity. Unless effective conservation measures are implemented, they will slide down the slippery slope of overfishing.
So, let me see if I understand this correctly: we can keep eating tuna until the stocks begin to slide down the the slippery slope towards extinction and then we can stop.

Now, that's one fine piece sensible assessment of the state of the tuna from an organization among whose founders you may notice some familiar names, including, Bumble Bee Foods, Clover Leaf Seafoods, Sea Value Co., StarKist Co., Thai Union Manufacturing Co. and Chicken of the Sea Intl. I don't need to say more, do I?

02 August 2009

A groundhog died in the woods and I found its skull

GroundhogSkull

This skull was a secondary find during last Saturday's field trip for Cepaea nemoralis. We were in a wooded lot next to a river, making it likely that it was a beaver skull. At the same time, not too far from the spot there were large tunnels dug into the soil at the edge of the forest alongside an open field, making it likely that it was a groundhog (woodchuck) skull.

A comparison of the skulls of the 2 species, let me identify it as a groundhog skull without any doubt. The groundhog (Marmota monax) is on the left, the beaver (Castor canadensis) is on the right. The most obvious difference is the "postorbital processes" of the groundhog skull that are missing in the beaver skull and which are present in mine.

GroundhogBeaverSkulls
Pictures from Mammalian Species.

The skull of a distant contender, the rabbit, eastern cottontail (Sylvilagus floridanus), is quite different from either species.

Cepaea nemoralis in Maryland—Part 2

Mbridge

Yesterday was a good day for a field trip, despite the heat and the humidity—and the abundant poison ivy everywhere. We surveyed the vicinity of the location where Cepaea nemoralis had recently been discovered (see part 1). We found additional colonies constituting what appears to be one widespread population.

The shell colors and band numbers of Cepaea nemoralis are notoriously polymorphic (Evolution MegaLab has a brief introduction). Various environmental (temperature, etc.) and biological (predators) factors are believed to influence the distributions of shell color and banding types in different habitats. The evolutionary implications of Cepaea nemoralis polymorphism have been studied for decades (again, check out the Evolution MegaLab pages for introductory information).

We found both empty shells and live specimens of 3 banding varieties all with yellow shells. There were unbanded snails and 5-banded snails.

CepaeaNemoralis5

And then there were 1-banded snails.

CepaeaNemoralis6

To better delineate the range of the species in our study area, we are planning further field trips on future hot and humid days. Watch this blog for updates.