Aquatic Beauties

 Here's a little beauty:

This is a Fragrant Water Lily, Nymphaea odorata. It's one of  approximately 36 species in the genus, itself one of 7 or 8 genera in the family Nymphaeaceae. According to the Flora of North America website, this is one of 9 species of Nymphaea that occur in North America.

The entire family is often referred to as water-lilies, of course, since they are entirely aquatic. They grow rooted to the bottom of ponds and slow rivers, with leaves submerged, emergent, or floating on the surface. The flowers are raised above the surface to some degree, as seen here:

In addition to their beauty, and their ecological importance in warm wetland areas, water lilies are of interest to botanists because of their taxonomic position. They are generally thought of as the second most basal group of angiosperms, branching off from the other flowering plants just after Amborella did so. A recent paper, however, argues that Amborella is the sister group of a Nymphaeaceae - Hydatellaceae clade. (Hydatellaceae is a small family of minute aquatic plants.) This means that the water lilies are direct descendants of that first branch off the flowering plants, basal to all of the other angiosperms.

Water lilies and Hydatellaceae are aquatic plants, but Amborella is a land plant, as are most of the angiosperms. So: were the original angiosperms aquatic, with Amborella climbing onto land, or were they terrestrial, with the water lilies aquatic preference evolving after that next split?

In a similar vein, Amborella has vascular tissue that is missing certain elements normally found in angiosperms (one reason why they've been considered a basal group). But if they're in a clade with two or three other families that do have that tissue, did they somehow lose those elements? Or is this an interesting case of convergent evolution between the Nymphaeaceae and the rest of the angiosperms?

The Evolutionary Root of Flowering Plants. Vadim V. Goremykin, Svetlana V. Nikiforova, Patrick J. Biggs, Bojian Zhong, Peter Delange, William Martin, Stefan Woetzel, Robin A. Atherton, Patricia A. Mclenachan, and Peter J. Lockhart. Syst Biol (2013) 62 (1): 50-61 first published online July 31, 2012 doi:10.1093/sysbio/sys070

Salt-water Musicians?

Here's a critter from deep in the archives (if not so deep in the sea).

This is a Brown Guitarfish (Rhinobatos schlegelii), from the Denver Aquarium. While he looks like a cross between a stingray and a shark, he's actually considered to be in the family Rhinobatidae, in the Order Rajiformes. (That is, he's a ray, but closer to the skates than the stingrays.) He's found in the western Pacific, from Korea to Australia. 1 There are 50 species of these guys, found throughout the warmer oceans of the world. 2  Mostly they hang out in shallow coastal waters, eating snails, clams, and other bottom-dwellers.

I haven't had much luck finding studies that focused on this one, although Fishbase does state that it's a fine eating species, but other species, such as the Common Guitarfish (R. rhinobatos) from the Eastern Atlantic and Mediterannean, and the Shovelnose Guitarfish (R. productus) from the west coast of the US and Mexico, are quite well-studied, from distributions to reproductive biology 3,4,5,6 to genetic variation. 7

That last study found something quite interesting to my mind -- unrecognized genetic differentiation between fish from the west coast of Baja California and those from the Gulf of California just to the east. The authors didn't go so far as to claim the two forms were separate species, but they did point out that this sort of variation should be a concern when we're contemplating conservation or management measures. This species isn't endangered, but several others are, including the Common Guitarfish. (Brown and Shovelnose are listed as data-deficient by the IUCN).8

While the Brown and Shovelnose aren't considered endangered, they are both heavily fished, so all of this study, including the ongoing taxonomic work, are very important, if we want to keep them around.


1) http://www.fishbase.org/summary/Rhinobatos-schlegelii.html

2) http://en.wikipedia.org/wiki/Guitarfish

3) Enajjar, S., Bradai, M. N., & Bouain, A. (2008). New data on the reproductive biology of the common guitarfish of the Gulf of Gabes (southern Tunisia, central Mediterranean). Journal of the Marine Biological Association of the UK, 88(05), 1063-1068.

4) Ismen, A., Yıgın, C., & Ismen, P. (2007). Age, growth, reproductive biology and feed of the common guitarfish (< i> Rhinobatos rhinobatos</i> Linnaeus, 1758) in İskenderun Bay, the eastern Mediterranean Sea. Fisheries Research, 84(2), 263-269.

 

5) Abdel-Aziz, S. H., Khalil, A. N., & Abdel-Maguid, S. A. (1993). Reproductive cycle of the common guitarfish, Rhinobatos rhinobatos (Linnaeus, 1758), in Alexandria waters, Mediterranean Sea. Marine and Freshwater Research, 44(3), 507-517.

 

6) Sandoval-Castillo, J., Rocha-Olivares, A., Villavicencio-Garayzar, C., & Balart, E. (2004). Cryptic isolation of Gulf of California shovelnose guitarfish evidenced by mitochondrial DNA. Marine Biology, 145(5), 983-988.

 

7) Márquez-Farías, J. F. (2007). Reproductive biology of shovelnose guitarfish Rhinobatos productus from the eastern Gulf of California México. Marine biology, 151(4), 1445-1454.

8) The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 16 October 2014.

(Nearly) Lost Wanderers

Early October, and soon we'll be seeing the last of these guys winging their way past the watch:

This is a Peregrine Falcon (Falco peregrinus). The name literally means wanderer, and it's appropriate. They live on every continent except Antarctica, and routinely show up in Hawaii.

There was a time, however, when this would have been an exceptional sight here in Illinois:

Starting after World War II, the US started using DDT to control mosquitoes and other insects. We used a lot of it, much of it for agricultural purposes. We didn't realize, though, that it bioaccumulates, (in other words, the higher trophic level you feed on, the more you absorb) especially in aquatic systems. Neither did we recognize that in larger doses it has serious impacts on calcium metabolism in birds.

Peregrines feed largely on ducks and shorebirds. (Well, today a lot of them feed on pigeons, but that's a rather new development.) That puts them squarely in a high trophic level, at the top of an aquatic system. So it's no surprise that they got doses more than high enough to disrupt calcium uptake. This is especially important for birds, since their eggshells are primarily made up of calcium. In the case of Peregrines, in the eastern US, eggs became so fragile that the females couldn't successfully incubate them. And by the early 1970's, Peregrines were no longer found east of the Mississippi.

After DDT was banned in the US in 1972, several of the most heavily impacted birds began to rebound. (Osprey, Bald Eagles, Brown Pelicans). But there weren't any Peregrines left to start a recovery. Into this gap stepped the folks at the Peregrine Fund. They raised a bunch of money, began to acquire Peregrines from elsewhere, and then learned how to successfully reintroduce them. As a result, they were removed from the US Endangered Species List in 1999.

But where did they come from? Therein lies an interesting debate on the nature of subspecies and the authenticity of our natural history.

The eastern anatum was gone -- there were a few pairs breeding in easternmost Canada that appeared to have been anatum, and that was it. Out west, they were still hanging on in scattered locations. So, what to do? Try to catch a few of the Canadian birds (which might have unfortunate effects on the one wild population left), or bring some western birds east?

Or you could try what the Peregrine Fund actually did -- bring in birds from all over the world, and rely on natural selection to sort out a new subspecies that would be well-suited to this new environment. (And a new environment it is -- many of the original nesting areas have become unsuitable, whereas many of today's birds nest in high-rise buildings in various cities.) These new birds are currently termed "mutts" by many raptor enthusiasts. I've been told that "nothing about Peregrine's nesting in Chicago is natural", to which I reply "What about Chicago IS natural?"

Admittedly, this is a long-term strategy. It will be decades, probably even centuries, before we can expect a population that is homogeneous enough to give it a subspecies designation all its own. But then again, that's how natural selection works.
One of the things that interests me about this is the insistence that the Canadian birds were still anatum, so they should have been used. Yes, they looked like birds from New York or Illinois, (or Florida, even), but does that mean that they would be genetically well-adapted to this area? That's an open question -- for most species, we don't have any idea how closely the genetics follow appearances across populations, and even if we did, we don't know which genes are important in adapting to local conditions. (Or even how closely those genes correlate with environmental variation.)

I do find the debate interesting, but fortunately for my own peace of mind, I find myself in agreement with the Peregrine Fund. This is a neat long-term experiment in applied evolutionary biology, and if we're still willing to do the work in the decades to come it could prove invaluable in helping us learn how species can adapt to the changes we like to make in our environment.

No matter how you feel about the current situation, though, it's neat to know that this shot could be across the sunrise of a new population, and not the sunset of a species: