30 September 2005

Moonrise over Büyük Menderes Delta

Ansel Adams took several moonrise photographs that have become classics. This is one of my attempts at pretending to be Ansel Adams. Unlike the way Adams took most of his photographs, however, I took this one without much preparation or visualization. I adjusted the exposure manually, as I almost always do, but otherwise, it was basically a "point and shoot" kind of thing.

The picture shows the delta of the river Büyük Menderes, the ancient Meander River, on the western coast of Turkey. On the right is the Aegean Sea. Until about 2000 years ago, the delta was a bay open to the Aegean, before the alluvium brought by the river filled it up. I will have more on that story in a future post.

Across from the delta on the slopes of the hills vaguely visible behind the haze and mostly just outside of the picture, lie the ruins of the Ionian city of Miletus. The battle of Lade was fought between the Ionian Greek and the dominating Persian navies off the island of Lade not too far from Miletus in 494 B.C.E. Lade is now just another hill surrounded by cotton fields.

I took this picture from the southern slopes of Mount Mycale on Dilek Peninsula north of the delta in July 2004 during our land snail survey. This would have been a good (and safe) spot to watch the battle.

29 September 2005

This meme needs no title

I wasn't going to post anything today, but Nuthatch at bootstrap analysis cruelly tagged me with this meme. Here it goes.

10 years ago: In 1995 I did a mandatory and, luckily, once-in-a-lifetime 30-day stint with the Turkish Army in the extremely dull town of Burdur in Turkey (I hope my friend Zeki, who lives there, is not reading this). All day long all we did was march up and down dusty roads and pull weeds from fields planted with vegetables. To remind us that this was actually military training, not some forced gardening exercise, we were taken to a target area just once and each of us was made to shoot two bullets with ancient World War II rifles, M-somethings, that had been taken out of storage for this special occasion (they are not used for any other purpose anymore).

The only good thing that came out of those 30 long days (actually 28, because we had 2 leave days) was that I was able to retain my Turkish citizenship. Now when I go to Turkey I take two passports, one Turkish and one American. Interestingly, it wasn’t until several years later when I was renewing my U.S. passport that I learned for certain that it wasn’t necessarily illegal for a U.S. citizen to serve in the military of another country or to carry two passports provided that certain conditions are met.

5 years ago: I had a trip to Turkey in the summer to collect snails, otherwise, nothing too memorable seems to have happened.

1 year ago: The most memorable event of 2004 was yet another summer expedition we had in Turkey. This one was lots of fun and I still have hundreds of snail shells that I need to sort, identify and then write papers about. Also, in September we went to Canada to my niece's wedding. That was fun too.

Yesterday: Was a routine day at my desk job. Took a long walk after lunch and photographed a large turtle in the lake. Otherwise, the most exciting thing I did was subscribe to the New Scientist. Now I am looking forward to getting the fist issue. I spent the evening photographing and measuring the snail shells I have on loan from the Field Museum in Chicago. The loan expired 2 days ago, so I am desperately trying to finish what I want to do, before I get a nasty e-mail from the collection manager asking me to return the material (I hope he is not reading this either).

5 songs I know all the words to: Hmmm…I know many songs, but I don’t think I know the entire words of any. But, wait, there’s one! Neil Young’s Till the Morning Comes: “I am gonna give you till the morning comes, till the morning comes, till the morning comes. I am only waiting till the morning comes, till the morning comes, till the morning comes.” A short song, indeed.

5 snacks: Chocolate covered pecans, yogurt covered almonds, dried mango slices, marzipan, chocolate covered pecans (yes, I really like them).

5 things I’d do with $100 million: Retire! Then, I would spend the rest of my long life studying nature. I guess I'd also found a foundation to fund research on evolutionary biology and donate some money to museums.

5 places I’d run away to: Hawaii, Australia, Charles Darwin’s house in Down, England and, if time travel were possible, two places in Turkey about 10,000 years ago after the ice age, but before the human assault on the environment started: the current location of Istanbul and on the west coast the area between the rivers Küçük Menderes and Büyük Menderes (the ancient Caystros and Meander, respectively).

5 things I’d never wear: Polyester shirts, a toupee (not that I need one), wool directly against my skin, because it makes me itchy, itchy, itchy…

5 favorite TV shows: I don’t watch TV anymore. The last show I watched regularly was Third Rock From the Sun, and before that Seinfeld. Now, once in a while, I may watch the Simpsons. Monday nite I wanted to tape the Bob Dylan documentary on PBS, but couldn’t get the VCR to receive the channel it was on and gave up. I’ll wait for the DVD.

5 greatest joys: Long walks in places that I am least likely to encounter people (not that I am antisocial), cats, photography, field trips to collect snails, late summer afternoons on the deck with my wife and a bottle of beer chatting and reading light stuff, blogs mostly (we call them “beer & daer” hours, “daer” being the backward spelling of “read”.)

5 favorite toys: My computer, digital camera (thinking of getting a new one), 2 microscopes (stereo and compound) and GPS receiver.

5 people I’m tagging: afarensis at afarensis, tony at milkriverblog, Alun at Alun, Henry at Webiocosm, last but not least, Pamela at Thomasburg Walks.

28 September 2005

Naughty beetles and evolution

Evolutionary biologist Ernst Mayr (1904-2005) liked to stress that basic evolutionary change is a two-step process1. The first step is the production of genetic variation in every generation. In sexually reproducing organisms genetic variation is created by random mutations in the DNA of eggs and sperm cells and also by genetic recombination. New genes may also be introduced into a population when an individual of the same species migrates over from another population. The essential characteristic of this step is that nothing, other than chance, guides the production of genetic variation.

The second step of evolutionary change is the choosing of the genotypes that will produce the next generation. This is where natural selection operates, while chance plays a less important role.

These mating soldier beetles (Chauliognathus pennsylvanicus, family Cantharidae) are in the process of generating variation. Soon the chromosomes in their eggs and sperm cells will recombine and generate the genes of their offspring. Any mutations in the parent beetles' DNAs will also be passed on to their offspring.

All the while, the beetles are under the ever watchful eyes of natural selection, which means that the individuals that are good at getting food, avoiding predators and other dangers or finding a mate are more likely to survive and leave offspring than those that are not as good.

Learn more about evolution at these sites:
Tree of Life
Fossil Museum
Talk.Origins Archive

1. Mayr, E. 1963. Page 128 in Populations, species and evolution; Mayr, E. 1988. Page 98 in Toward a new philosopy of biology.

27 September 2005

A colorful predator: Gulella bicolor

This strikingly colorful land snail, sometimes placed in the subgenus Huttonella, is not native to the U.S. Its original homeland may be South Africa or India. It was first recorded in the U.S. in the early 1950s1. I found this specimen last July near Fort Myers, Florida.

Gulella bicolor, whose shell grows to be about 7 mm long, is a predator of other equally small snails. In one study, starving captive individuals of G. bicolor did not eat several plant species given to them2, suggesting that they are strict carnivores. Fortunately for native snails, Gulella's main prey appears to be Subulina octona, another introduced snail in southern U.S. I kept two specimens of Gulella for about a month and fed them very small juveniles of Subulina. Unfortunately, I didn’t have a chance to photograph the predators in action.

The information on this snail at some web sites is inaccurate. For example, the description at the Gulf States Marine Fisheries Commission web site states that “Living specimens appear two-toned since the shell is red-orange anteriorly, and yellow posteriorly.” It is not the shell that is colored red and yellow, but the snail’s body. The shell itself is translucent white.

1. Dundee, D.S. 1974. Catalog of introduced molluscs of eastern North America. Sterkiana. No. 55:1-37.
2. Dundee, D.S., and R.J. Baerwald. 1984. Observations an a micropredator, Gulella Bicolor (Hutton) (Gastropoda: Pulmonata: Streptaxidae). Nautilus 98:63-68.

26 September 2005

"Take me to the Moron-in-Chief”

The other day while on my way to the National Museum of Natural History (the building behind the eraser) in Washington, D.C., I took the scenic route through the National Gallery of Art Sculpture Garden. When I was passing by the giant typewriter eraser, I remembered this Zippy strip from last July.

Curiously, this thing by Oldenburg and van Bruggen was erected not too long ago when typewriters had already become obsolete. Was this some kind of nostalgic art experiment or is Zippy onto something?

25 September 2005

Bagworm city

Ever since I came upon a bagworm moth caterpillar (family Psychidae) hanging from a tree back in July, my eyes have learned to recognize them. Now, I see them rather frequently. A couple of days ago I found a bunch of cases attached to the side and the underside of the iron guardrail along a local street.

Each bag was 15-18 mm long and constructed of pieces of grass blades. I suspect these caterpillars, which are now pupating inside their cases, eat grass. I brought a couple of them home hoping that the moths will soon come out and I will photograph and perhaps identify them.

23 September 2005

Special of the day: Whitefish with occasional parasitic cysts

Did you know that the U.S. Food and Drug Administration (FDA) allows for the presence of certain levels of insect parts and "rodent filth" in our food? It would be practically impossible to avoid contamination of very large quantities of commercially produced food, especially grains and other plants, by insects and rodents. And since such contaminations do not normally pose any health hazard, FDA allows for their presence up to the maximum levels that have been established for different food items. These maximum levels are known as "Food Defect Action Levels".

Here are some examples of Defect Action Levels of filth in food.

Frozen broccoli: Average of 60 or more aphids and/or thrips and/or mites per 100 grams.
Chocolate: Average of 1 or more rodent hairs per 100 grams.
Curry powder: Average of 4 or more rodent hairs per 25 grams.
Whitefish: 50 parasitic cysts per 100 pounds (whole or fillets), provided that 20% of the fish examined are infested.
Red Fish and Ocean Perch: 3 % of the fillets examined contain 1 or more copepods accompanied by pus pockets.
Ginger, whole: Average of 3 mg or more of mammalian excreta per pound.
Peanut butter: Average of 30 or more insect fragments per 100 grams.
Tomatoes, canned: 5 or more Drosophila eggs and 1 or more maggots per 500 grams.
Wheat flour: Average of 75 or more insect fragments per 50 grams.

Bon appétit!

Appreciations to Tim Pearce whose e-mail responses to one of my previous posts on eating cockroaches inspired this one.

22 September 2005

Backyard bugs II: banded net-wing

Although this insect (Calopteron reticulatum) may look like some sort of moth, it is actually a beetle (order Coleoptera, family Lycidae). I didn't photograph it in my backyard, but near the lake not too far from my house. They seem to prefer wet habitats and luckily, my backyard isn't that wet (we have enough mosquitoes as it is).

In the previous edition of backyard bugs that featured the spotted cucumber beetle, I mentioned that the beetles are the most speciose group of insects. The chart below illustrates how beetles fare, in terms of species numbers, compared to all other organisms. If you are wondering where the mammals are, they are in the group called chordates that occupies a barely visible slice.

Now we know who the real owners of this planet are.

Chart from here.

21 September 2005

Special of the day: sautéed cockroach with onions

In a chapter he wrote about the "intellectual and emotional world of the cockroach", entomologist Howard Ensign Evans included the story of a rather unusual dinner experience of his1.

I once had a cockroach served to me in an order of beefsteak and onions in Texas. (I believe it was an American roach, but accurate identification of fried specimens is difficult.) I was ravenously hungry after a day in the desert, so I cleaned my plate except for the cockroach, which I spread out neatly in the center of the empty plate, arranging his antennae and legs as best I could. The expression on the waiter's face when he picked up my plate was ample compensation for the health risk I took. Cockroaches are basically clean animals, but they do track about a good deal of human filth; domestic roaches have in fact been found to carry bacteria responsible for a variety of intestinal disorders, as well as polio virus and even hookworm. I survived my Texas meal well, although my sorting out of fried onions from fried roach parts was sometimes arbitrary.

As much as I like insects, I don't think I could eat a meal containing a cockroach. But I suppose I wouldn’t mind a snail crawling on my salad. Do we tend to be less prejudiced against what we are more familiar with?

1. Evans, H.E. 1968. Chapter 3 in Life on a Little-known Planet.

20 September 2005

Cement shoes for a squirrel?

Footprints of a gray squirrel (Sciurus carolinensis) on a sidewalk (composite image).

19 September 2005

Land snails of Turkey: Oxychilus urbanskii (Pulmonata: Zonitidae)

This species was described by Adolf Riedel in 1963. It is in the subgenus Morlina. The type location is Gramatikovo in southeast Bulgaria. Riedel1 has also recorded it from several locations in northwest Turkey.

The specimen pictured here (FM2802282) was collected (and identified) by Riedel at Inkaya on the Uludağ Mountain near Bursa, Turkey in 1983. Most Oxychilus species have indistinct shells that are hard to tell apart from each other. In this case, I am assuming that Riedel’s identification was correct.

The pictured specimen was a subadult 9.1 mm in diameter with 5 whorls. A larger shell in the same lot had a diameter of 11.4 mm. The upper and lower surfaces were mostly smooth and shiny without distinct growth rings. I noticed no microsculpture on either the protoconch or the teleoconch at magnifications up to 40x. The umbilicus was very narrow.

Riedel3 named this species after the Polish malacologist Jaroslaw Urbanski (1909-1981).

1. Reidel, A. 1995. Zonitidae sensu lato der Türkei. Übersicht der Arten. Fragmenta Faunistica, 38:1-86.
2. Field Museum of Natural History, Chicago.
3. Reidel, A. 1983. Jaroslaw Urbanski (1909-1981). Archiv für Molluskenkunde, 113:1-5.

17 September 2005

Saturday nite's draft cider review: K

This stuff is good. When I saw it in my usual beer store I didn't quite know what it was. The ingredients list apple concentrate, CO2 and a few other things. It appears to be fermented apple cider; it tastes like apple cider, but it is less sweet. The label gives the alcohol content as 6.9%. It is produced in England and imported by K-Cider Co. in New York.

After I took the above photo out on the deck, I picked up the bottle and went inside to download the picture. As I was sitting by the computer, I noticed a tiny fly flying around the mouth of the bottle. And when it landed on the bottle I recognized it as a fruit fly (Drosophila) from its conspicuous red eyes. I grabbed the camera and took a picture of it too.

If Drosophila is attracted to K, it must be the real thing!


The previous beer review was Purple Haze.

16 September 2005

The books in the bag

Nuthatch's post about her recent reading reminded me that it's been a while since my previous books in the bag. So, here are some selections from my recent and current reading.

Shipwrecks and Archaeology by Peter Throckmorton. Little, Brown & Co., 1970. I have an armchair interest in underwater archaeology (actually, I am a certified scuba diver, but I haven't dived since 1998). So, when I chanced upon this book at the used bookstore for $3, I couldn't pass it. Another reason for my interest was that Peter Throckmorton (1928-1990) spent several years in Turkey in the late 1950s and early 1960s and was responsible for the initiation of underwater archaeology in that country, although, to my disappointment, he has very little in this book about that period of his life. Nevertheless, Throckmorton was a good writer and this is a fine book with long accounts, including some technical drawings, of several wrecks that Throckmorton discovered mostly in the Aegean Sea, some dating to the Roman Period, while others to the 19th century, including that of H.M.S. Nautilus from 1807.

Amphibians and Reptiles of Delmarva by James F. White, Jr. & Amy Wendt White. Tidewater Publishers, 2002. I had first borrowed this little book from the local public library. But it was so useful, I decided to get my own copy (it was also relatively cheap at Amazon). Although, as the title implies, it is intended strictly for the Delmarva Peninsula, my part of Maryland, being not that far from Delmarva, has more or less the same species. For each species, there is a color photograph, a detailed description, and information on its habitat, reproduction and other natural history characteristics.

Lichens by William Purvis. Smithsonian Institution Press, 2000. I have long had an interest in lichens, but never had a chance to learn much about them. When I saw this book in the public library last week I thought I would take it out and read it. It turned out to be a pretty good introduction to lichens with lots of informative color photographs and drawings. But the discussions of some particular subjects were too brief to satisfy me. Also, many tantalizing bits of information are given without precise literature citations. For example, the "oldest undisputed fossil lichen" is stated to be Winfrenatia reticulata from about 400 million years ago, but it is left to the readers to track down more information on it. Footnotes with specific literature citations would have been very helpful.

I wonder what Tony G over at milkriverblog has been reading.

15 September 2005

Peck's Skipper: a suburban butterfly with a message

I photographed this Peck's Skipper (Polites peckius; also known as Yellowpatch Skipper, Polites coras) a couple of days ago in Riverdale Park, Maryland. On a lone thistle a few meters away from the railroad tracks, it was getting its nectar seemingly oblivious to me and the constant stream of cars and the occasional freight trains―one had passed by moments earlier.

There are many native species like this butterfly that seem to be doing equally well both in pristine (if any place still fits that description) and highly modified habitats. Some more familiar examples are the gray squirrel (Sciurus carolinensis) and the American robin (Turdus migratorius).

This shouldn't, however, lead us into comfortably believing that we have reached some sort of alliance with nature. Some of us may have partially accomplished this with a limited number of species of butterflies, birds and small mammals, but that's about it. Many more species require, and should have, much less disturbed habitats as far away from humans as possible. Nobody would want grizzly bears in city parks and termites in their backyards.

Previous posts with conservation themes:
Deadwood is good
Urban nature, or the lack thereof

14 September 2005

What would Ansel Adams do?

In a previous post about digital photography, to overcome the rather long time lag of digital cameras, I suggested taking many shots of a subject with the hope that at least one will turn out good. This is something professional photographers do all the time even when their cameras have no noticeable time lag.

It turns out that the master perfectionist Ansel Adams was against this practice1.

The technique of 35mm photography appears simple, yet it becomes very difficult and exacting at the highest levels. One is beguiled by the quick finder-viewing and operation, and by the very questionable inclination to make many pictures with the hope that some will be good. In a sequence of exposures, there is always one better than others, but that does not mean it is a fine photograph!

I am with Adams if the subject is a bunch of boulders in the sun, trees in a forest, or a hillside in Yosemite. But, most of the time I am going after hyperactive butterflies, paranoid mantises and the like. Even a proverbially slow snail doesn't leave much time for exposure calculations and visualizations of the final image à la Adams.

Today it took me about 20 minutes in the hot sun and more than 10 shots to get the half decent picture of the Pearl Crescent (Phyciodes tharos) below. The butterfly is still not as sharp as I would like it to be. So, if your subject is there one moment and gone the next, take as many shots as you have patient or room for in your picture card.

1. I came upon this while reading Adams' wonderful book Examples: The making of 40 photographs (Little, Brown & Co. 1983). I will have more on that book some other time.

13 September 2005

Self-portraiture in the elevator with mirrored ceiling

What do you do when you are alone in an elevator?

The picture below is the original before I lightened it up (quite a bit) in Photoshop.

12 September 2005

Digital photography notes

Part 1: time lag of digital cameras

Time lag of a camera has been defined1 as “the interval between the first pressure on the trip button and the beginning of exposure”. Time lags of several models of SLR film cameras (mid-1980s models) varied between 46 and 230 milliseconds 1.

To estimate the time lag of my Olympus Camedia C-5000, I photographed my stopwatch at 10, 20, 30, 40 and 50 seconds2. The picture below shows the results obtained with the focus manually fixed before the start of the test.

The average of the individual time lags (1.1, 0.97, 1.16, 1.03, 1.03 seconds) is 1.06 seconds or 1060 milliseconds. This is huge compared to time lags of film cameras. The time lag is further lengthened if the camera is in autofocus mode as was the case in the test below.

Now the average lag is 1.87 seconds; almost a second longer. Other models of digital cameras probably have comparably long time lags.

You’d be amazed when you realized how much peoples’ facial expressions and body postures or the positions of a butterfly’s wing positions could change in the span of a second. To get around the long time lags of digital cameras learn to anticipate the movements or positions of active subjects and try to press the shutter button a second or two before the anticipated moment. This is harder done than said. Another way to shorten the time lag when photographing a subject whose position relative to you will remain constant is to turn of auto focus and to adjust the focus manually once in the beginning. For example, if you are photographing a distant event, say, a soccer game, you may manually set the focus to infinity, thereby shortening the time lag by about a second.

Finally, if you are photographing a rare event do what professional photographers do: take many pictures, hoping that at least a few will come out fine or just perfect.

1. Goldberg, N. New, state-of-the-art SLRs are impressive, but what about their irksome time lag? Popular Photography. Unknown issue, pp. 72-74, circa 1986.
2. This is, of course, not the best way to take such measurements. The measured time lag also included the time lag between the moment my eyes relayed an image to my brain, which issued the command “Press the shutter now!”, and the moment my finger started pressing the shutter. This physiological time lag is probably highly personal and variable depending on the person’s state of alertness.

10 September 2005

Happy Birthday Temi!

This month Temi (short for Artemis) turns 17. It is hard to believe that it's been so long since we first spotted her all the way in the back of a cage at the Humane Society in Ann Arbor, Michigan. We hope that she will be still with us to celebrate her 20th birthday.

Nuthatch at bootstrap analysis declared her cat Sophie to be the "cutest cat in the world". We have, therefore, no choice but to declare Temi the Cutest Cat in the Universe.

09 September 2005

Today's good words: euphallic, aphallic and hemiphallic

Pulmonate land snails are hermaphrodites, which means that each individual makes both sperm cells and eggs and normally has both a vagina and a penis. The organ that produces sperm cells and eggs is appropriately called the ovotestis (there's another good word).

Evolution, however, doesn't care much for rules; if a species will be better off by breaking a rule, the rule will be broken. Thus, there are many species of pulmonate snails that have ovotestes, but lack penises. Sometimes, some individuals of a species may have fully developed penises, while others may entirely lack penises. In such cases, a snail with a normally developed penis is said to be euphallic and an individual that lacks a penis is aphallic.

Finally, a snail may have an underdeveloped or a degenerate penis. Such a snail is hemiphallic1.

The genitalia of euphallic (left) and aphallic (right) specimens of the European snail Aegopinella nitens. In the aphallic specimen the vas deferens is a blind tube. Drawings of genitalia from Riedel2.

The reason why I brought up these terms is that some authors have associated aphally with miniaturization of land snails. In future posts I will return to this subject in greater detail.

1. The use of the terms hemiphallic and euphallic was first suggested by Hugh Watson in 1934 (Genital dimorphism in Zonitoides, Journal of Conchology, 20:33-42).
2. Riedel, A. 1953. Male copulatory organs deficiency in the Stylommatophora with a special reference to Retinella nitens. Annales Musei Zoologici Polonici, 15:83-98.

08 September 2005

Backyard bugs I: Spotted cucumber beetle

This is the well known Diabrotica undecimpunctata. I photographed it while it was munching on the flowers in my backyard. Its species name, undecimpunctata, meaning "11-spotted", refers to the 11 spots (or 12, depending on how you count the two adjacent uppermost spots) on its elytra (fore wings).

Beetles (Coleoptera) are the most speciose group of insects. In fact, almost 30% of all known animal species are beetles according to this web site. The oldest beetle fossils are about 265 million years old.

More information:

morphology and evolution of beetles

Insect evolution

The fossil record of major insect groups

07 September 2005

Pictures from high above 4: San Francisco Steinberger Slough

This is the 2nd picture that I took on 30 June 2005 as my plane was approaching the San Francisco Airport. Yesterday’s photo was the salt evaporators just north of Redwood City. This one shows an area 4.1 km north of yesterday’s picture.

Once again, I was able to identify the area in the photograph thanks to the satellite photo at Google Maps. Note the power transmission lines crossing the canal (Steinberger Slough), visible in both my photo and in the Google satellite photo, which was taken from directly above.

The area in my photo is within the yellow rectangle in the topo map from TopoZone. Compared to the Google satellite photo, the topo map is hopelessly out of date: the area marked “salt evaporators” on the topo map is now covered with houses.

Using the scale bar on the Google satellite photo, I estimated the distance between the areas in yesterday’s and today’s photos as approximately 4.1 km (2.57 miles). The time difference between the two pictures, as recorded by my digital camera, was exactly 50 seconds. Using this information, I calculated the speed of the plane within that interval as 295 km/h (185 miles/h).

There is a 3rd photo taken about 10 minutes earlier. It shows a coastal development without any distinct landmarks. If I ever identify it on a map, I will post it here too.

06 September 2005

Pictures from high above 3: San Francisco saltworks

I took this picture on 30 June 2005 as my plane was approaching the San Francisco Airport. It shows the salt evaporators just north of Redwood City. The approximate boundaries of the area in the picture are within the red lines in the topo map below from TopoZone.

I first identified the area in my photograph on the satellite photo at Google Maps. If it wasn’t for the satellite image, I would have had a hard time locating it on the topo map.

Tomorrow: another photo 50 seconds later.

The previous picture from high above was the Potomac River.

05 September 2005

The Emperor and I

Butterflies must like me. A week ago I attracted one with my hat. Last Saturday while hiking along the C&O Canal down by the Potomac river, this beautiful Hackberry Emperor (Asterocampa celtis) developed a more intimate interest in me. First it landed on my shorts, then on my shirt and finally on my left hand. Luckily, I hold the camera in my right hand and was able to take a series of close-ups of it (I am ambidextrous; I write with my left hand, but do many other things with my right hand).

As you see in the above photo, the butterfly had its proboscis uncurled and was constantly probing with it around the tip of my finger and along my nail. Obviously, there was something there that it was after. Sweat, maybe? Today, I remembered that before I had left home about an hour earlier, I had sprayed cologne on my shirt (I always operate the spray bottle with my left hand). Perhaps, the sensitive receptors on the butterfly's proboscis could detect the few molecules of perfume that were still on my skin.

03 September 2005

Land snails of Turkey: Chondrus tournefortianus

This land snail was discovered by the French botanist Joseph Pitton de Tournefort (1656 - 1708) and mentioned in the posthumous account of his travels in the lands of the Ottoman Empire (Relation d'un voyage du Levant, 1717). André Férussac formally described the species in 1821 and named it after Tournefort.

In an earlier post, I had a map of the approximate distribution range of Chondrus tournefortianus in Turkey and the adjacent areas.

The shell of this species is normally sinistral. It is usually claimed that the function of the apertural teeth present in the shells of many species of land snails is to prevent predatory beetles from entering the shell. To my knowledge, however, that this is indeed the case has not been conclusively demonstrated.

02 September 2005

Friday nite's beer review: Purple Haze

This is a flavorful beer with a light raspberry aroma and a purplish golden color with quite a bit of turbidity. The label claims that it is made by adding raspberry puree to each batch. The label also says that it is sweet, but I didn't think it was. I enjoyed it.

Purple Haze is brewed by the Abita Brewing Company of Abita Springs, Lousiana.


The previous beer review was Stovepipe Porter.

Let the best lineage win

A paper on Ichthyostega, one of the oldest known amphibian fossils, was published in yesterday's Nature1. For more information on the significance of this fossil for our understanding of the development of terrestriality among vertebrates, I recommend the posts at afarensis and Pharyngula.

What got me interested in this subject was the accompanying News & Views article by Robert L. Carroll2. In the last paragraph of his essay, Carroll points out that among the at least 11 lineages of lobe-finned fish and early amphibians from the Devonian, only one appears to be a close relative of the extant land vertebrates. All other lineages, including that of Ichthyostega, seem to have died out. Carroll also mentions that similar "ultimately unsuccessful experiments" took place during other major transformations in the evolution of vertebrates, including the evolution of several species of Homo, only one of which remained.

The development of terrestriality was also a major event during the evolutionary history of gastropods. Several lineages of marine gastropods independently invaded land3 and, unlike the early vertebrate pioneer lineages that ultimately failed, many of these gastropod lineages seem to have survived. An incomplete list of extant gastropod families that appear to have become terrestrial independently of each other include the Cyclophoridae, Pomatiasidae, Helicinidae and the Truncatellidae. Of course, the most successful group of them all is the stylommatophoran pulmonates. These are the land snails that carry their eyes on the tips of the upper pair of their two pairs of tentacles (for an exception to the usual two pairs of tentacles, see this previous post of mine on Vertigo).

The stylommatophorans have evolved the most number of species of terrestrial snails and invaded most terrestrial habitats, including deserts. In these respects, they have, therefore, been more successful than the other gastropod groups that became terrestrial. Many of the non-stylommatophoran land snails either have fewer species or are much restricted in their habitat preferences.

Thus, it seems that during the early evolution of the major animal groups, such as the vertebrates or the gastropods, several groups independently attempted the same major lifestyle change, but ultimately either only one group succeeded or several groups succeeded with one of them becoming much better at the new lifestyle than the rest.

This is certainly worth developing further, but it is too late in the night for that.

1. Ahlberg P.E., Clack J.A., Blom H. 2005. The axial skeleton of the Devonian tetrapod Ichthyostega. Nature, 437:137-140.
2. Carroll, R.L. 2005. Between water and land. Nature, 437:38-39.
3. Barker, G.M. 2001. Chapter 1 in The Biology of Terrestrial Molluscs (Barker, G.M., ed.). CABI Publishing.

01 September 2005

Two turtles with one shot

I photographed these turtles about 10 days ago in Lake Artemesia in College Park, Maryland. The one on the left is an eastern painted turtle, (Chrysemys picta picta), while the one on the right is a red-eared slider (Trachemys scripta elegans). The piece of log they were on is a favorite basking spot of the turtles in the lake, for I often see at least one on it.

Although one is tempted to think that the ancestors of extant turtles were aquatic and that some of their descendants evolved to become terrestrial, a recent study suggests the opposite. Joyce & Gauthier1 demonstrated that extant turtles have different forelimb morphologies depending on whether they are aquatic or terrestrial (shorter hands on land for walking, longer hands in water for swimming). When they applied this analysis to the forelimbs of two of the closest extinct relatives of turtles, the results indicated that the earliest turtles were land animals.

More information on these turtles and turtle evolution:

Red-eared slider (Trachemys scripta elegans)

Amphibians and Reptiles of Long Island, Staten Island and Manhattan

Fossil Turtle Newsletter

Transitional Vertebrate Fossils FAQ

Appreciations to Butch Norden of Maryland DNR for his help with the identifications.

1. Joyce, W.G. & Gauthier, J.A. 2004. Palaeoecology of Triassic stem turtles sheds new light on turtle origins. Proc. R. Soc. Lond. B, 271:1–5. full text pdf