minor musings on the macrocosm
Whilst yez all labor over IDs for the last post here’s some more fore yez:
all rotten and laced with clues. and bacteria.
POSTSCRIPTO: Apologies for the subliterate turn, sadly it’s not the first time. It’s metaphorical. It’s a coping mechanism. My lease on blogging is neither new nor transferable.
Venom–toxic fluid injected to subdue prey or deter potential predators–is widespread in the animal kingdom, from jellyfish to scorpions to platypodes. A case could even be made that stinging nettle is an example of a venomous plant, since it injects its toxin into victims. However, most toxic plants, as well as toxic animals and fungi that rely on passive delivery of toxins (e.g. newts) are considered poisonous but not venomous.
Snakes are one of the most familiar groups of venomous animal although a majority of snakes lack venom. Most people are also aware of the venomous beaded lizards (or, “gila monsters”) in the genus Heloderma. Far less well known is that varanid monitor lizards and bearded dragon, Pogona, popular in the pet trade, also possess a mild venom. We’re talking real venom here, not the bacterial brew that produces the much discussed septic bite of some varanid lizards. In fact, the discovery that venom occurs in reptiles aside from snakes and Heloderma was made only a few years ago and has forced us to rethink the evolutionary origins of venom among squamates (Fry et al. 2006).
So, what does any of this have to do with enigmatic Triassic hellasaurs? Read the rest of this entry »
Mesoplodon traversii – by Jennifer Rae Atkins.
The internets are an inspiring place. Inspired by the alignment of Tetrapod Zoology’s Week of Seriously Frickin’ Weird Cetacean Skulls and the final installment of The Lord Geekington’s expansive beaked whale treatise, I’ve dusted off a draft that has been adrift in the tubular doldrums since December. Seriously.
But, inspired mostly by The Daily Mammal’s Jennifer Rae Atkins:
When George Shaw received the first platypus skin to make it to England in 1789, he took a pair of scissors to it to look for stitches, or so the story goes. “It is impossible not to entertain some doubts as to the genuine nature of the animal,” wrote Shaw. Surgeon, and racist, Henry Knox argued that the Asian itinerary by which the specimen had traveled was, “sufficient to rouse the suspicions of the scientific naturalist, aware of the monstrous impostures which the artful Chinese had so frequently practiced on European adventurers.” Of course, the reality of this chimerical creature has long since been recognized, and, as of this week, we have the unique genome to prove it.
More recently the “Archaeoraptor” scandal raised echoes of Knox’s Sinophobia, and this weeks’ hellasaur is certainly enough to raise eyebrows. Hupehsuchus nanchangensis, has that “designed by committee” look, with the limbs of a basal ichthyosaur, the dorsal armor of a placodont and the bill of a…well, duck. But the fossils indeed check-out: this is no “monstrous imposture”, just one freaky-ass (or if you rather, enigmatic-ass) hellasaur.
Hupehsuchus nanchangensis by Zach Miller
And the more you look, the weirder it gets…more tomorrow!
If you’re hoping to make it into the fossil record, being a small, arboreal insectivore is probably not the best way to go. Forest soils are veritable compost heaps: acidic and crawling with critters and fungi that would happily mill your remains to humus given half a chance. And your scrawny, flexible skeleton is highly unlikely to endure the vicissitudes of long distance transport to some more suitable sedimentary environment.
Of course if you’re reading this blog chances are good that you’ve already been born so it may be too late to fix this. But don’t worry–there is a back up plan: find a lake, and fall in. Hey, it worked for Longisquama and Sharovipteryx, though a case could be made that they would have saved everyone a lot of trouble if they had just rotted on the forest floor like a respectable forest dweller.
The Triassic Madygen Formation of Kyrgyzstan is among the most important sources of Triassic insect fossils in the world (Fraser 2006). In fact, I’d almost rather write about the titanoptera, an “enigmatic” insect group which included the 30-cm wing-spanned Gigatitan vulgaris that may have looked something like the result of an unholy love-affair between a coackroach and a mantis…on crack. But this is “Hellasaur” Thursday so I’d better stay focused.
Left: LANDSAT image of Madygen Formation outcrops – de.wikipedia
In fact, it was the search for insect fossils that led to the discovery of two the Triassic’s more problematic hellasaurs. The first, Sharovipteryx mirabilis, is bad enough, what with its bizarre hind-limb “delta wing” and its purported link to pterosaur evolution despite its patagium-backward construction. We’ll leave Sharovipteryx be for now because our topic at hand is going to require the full bottle of Excedrin.
Longisquama insignis type specimen.
Behold, Longisquama insignis, “remarkably long-scaled” as the rather prosaic scientific name would have it. “Remarkable” is certainly *one* way to describe Longisquama. Whether the protarded 10 to 15 cm long structures which appear to project from its back are scales is (as Zach noted in the comment to a previous post) up for debate.
Some argue that the strange frond-like structures are the foliage of some unknown plant. They do look vaguely vegetative, although other plant matter on the slab appears to show a very different style of preservation and Fraser notes that they have “a peculiar venation pattern that is inconsistent with any known Triassic foliage types. The structures certainly appear to be physically associated with the skeleton itself, and most who have examined the fossil seem to accept that they belong to the skeleton, though the ‘consensus’ ends abruptly there.
One camp holds that they are feathers (which are, of course, modified scales) (Jones et al. 2000)! If this were true it might seriously upset the notion that birds are derived theropod dinosaurs. However, this view is a decided minority and a vast array of other skeletal evidence as well as the preservation of far more convincing feathers on some theropod fossils weigh heavily in favor of the birds-as-dinosaurs hypothesis. That is, unless maniraptoran theropod “dinosaurs” are secondarily flightless birds that merely look like dinosaurs….
Anyway, if the nature of these structures remains contentious, then establishing their function has basically been an interpretive free-for-all. A number of authors have tried to turn them into a parachuting or gliding apparatus of some sort. However, unless they supported a membrane, or were filled with helium, it’s hard to imagine how this would have worked. That said, a recent phylogenetic analysis suggests Longisquama may have been closely related to Coelurosauravus a Permian diapsid with a slightly more (though perhaps not altogether) convincing gliding membrane projecting from its sides.
Left: Longisquama as plumulus glider – Oregon State University.
Display –either to attract mates or perhaps to scare off potential predators or intraspecific rivals—is another popular explanation and probably a more convincing one. Elongate plumes in birds are exclusively a sexual selection affair; in fact their value as a sexual symbol may be directly linked to their hindrance to locomotion.
Scissor-tailed Flycatcher – Tyrannus forficatus
Another, admittedly fanciful, scenario is that the resemblance to a plant frond is not-coincidental. Could the scales of Longisquama be some extreme cryptic adaptation? Perhaps they hid the animal from predators or provided cover allowing Longisquama to ambush its supposed insect prey? Structural mimicry of plants is rampant among arthropods and in addition to more familiar cryptic coloration patterns, a number of land vertebrates use posturing as well as modified skin surfaces to blend into their surroundings
While sexual advertising and cryptic camouflage would appear to be at odds with one another there are animals well-equipped for both. Notably, for our purposes, chameleons, who are at once exceptionally cryptic and at the same time often sport elaborate sexual signaling structures like horns and crests. While chameleons probably don’t adjust their colors to match their background as popularly believed, color switching does allow them to temporarily display their mood to another individual then switch back to their more cryptic “normal” coloration when the mood has passed.
To continue our cautious, chameleon-like walk out on a very thin limb, it’s interesting to note that Longisquama’s skull, as figured by Senter (2004) (shown left), bears a remarkable superficial similarity to that of a chameleon [Note that other, very bird-like reconstructions of the skull out there are probably inaccurate, especially with regards to the supposed antorbital fenestra which is likely a preservational artifact]. The skull of Longisquama’s cousin Coelurosauravus is perhaps even more chameleon like. I’m not prepared to make an argument for functional convergence here, but to me the resemblance is quite striking.
Longisquama is certainly not closely related to chameleons, but its probable close relatives the enigmatic hellasaurs known as drepanosaurs, have been inferred to have had a chameleon-esque lifestyle. One wonders if this interpretation might be extended to Longisquama. Was it lurking in the Triassic treetops, flashing chromatophoric signals across its crazy dorsal scales and snagging titanopterans with a ballistic tongue?
Left: Longisquama by Matt Celeskey
Or, have I just been out in the sun to long?
refs-
Fraser, Nicholas 2006. Dawn of the Dinosaurs Indiana University Press
The kind of thing to drive any formerly self-respecting paleontologist nuts: underwater olfaction in mammals. Smell is an important sense for mammals, no surprise to anyone who has stepped into a Sephora outlet recently. Though we are generally far more conscious of sight and sound, we’re still led around by the nose far more than we would guess…especially when it comes to eating and mating.
And other mammals, especially those who have stuck to more respectable mammalian lifestyles (i.e. grubbing around for worms and bugs at night), put humans to shame in the olfaction department. Still, the announcement that some specialized “insectivorans” (or soricomorphs if you’re T.C. like that) are able to smell underwater came as a surprise – to me at least.
As seen in the photo above, this amazing feat is accomplished by expiring a small bubble of air then re-inspiring it. This allows these air-breathing mammals to safely search for odors underwater as they search for prey. Notably, many other aquatic mammals rely exclusively on other senses especially hearing and touch; whales have apparently little or no sense of smell judging from their brains.
A detailed analysis of the tactile and olfactory abilities of the American Water Shrew (Sorex palustris) in PNAS, expands upon the initial report of underwater smelling by shrews and moles. Like the previous Nature paper there are awesome photos and slow-mo videos documenting this amazing behavior, highly recommended.
The elaborate experiments by Catania and co. showed that S. palustris uses a combination of tactile (via whiskers) and olfactory clues to evaluate potential prey items. One video shows a shrew puzzled by an artificial cricket which apparently “feels” right but “smells” wrong. They also used experiments to rule out echolocation or electroreception – strategies employed by other mammals that forage underwater.
As for the paleontological lament: it took a serendipitous flash of insight plus the availability of high speed cameras and infrared lighting to bring this interesting behavior to light. One has to wonder how many strange behaviors among fossil taxa, peculiar and mundane, have yet to and may never be guessed at.
Interestingly, aquatic olfaction has been suggested in plesiosaurs based upon skeletal evidence, but I suspect we’ll be waiting awhile for the slow-mo vid.
Sure, it may be the Year of the Frog, but what is this dude, chopped limb? No. He’s a Southern Two-Lined Salamander, Eurceya cirrigera, that I found beneath the leaf litter in the woods behind Jessica’s old (okay, not that old) Kentucky Home. He showed up on New Years Eve as if to remind us that if 2008 is a year to celebrate hopping croakers, 2007 was a great year for writhing squirmers:
All 3 Taricha torosa pics = J. Lo.
That last nerdy pic seems an appropriate segue to a Schrutian diatribe:
THESIS: The various magical powers attributed to salamanders by classical and medieval authorities [Paracelsus, I'm looking at you] can barely hold a candle to the actual feats of urodeles and their skin-snacking cousins the caecilians.
FACT: Urodeles can regrow entire limbs (snap!)
FACT: Dudeski once ate a Taricha newt (in my hand above) on a dare and DIED.
FACT: All salamanders respire across their skin and some (like the Eurycea in the first picture) have lost their lungs entirely.
FACT: Woah.
NOT-FACT: Salamanders spring-forth fully formed from stones cast into a fire.
So, I won’t waste my time wishing y’all a happy holiday. I converted to animism on I-5 just south of Lodi, beneath a wheeling gyre of White Pelicans. Mahayana blows
dude. Sorry.
Those pelicans then shall be our collective mascot this holy season, their holding pattern a gleaming metaphor for our soul. Which is to say, don’t be surprised if things are pretty quiet around here for the rest of the week.
In the mean time:
- Jennifer Rae Atkins pulled of the astonishing feat of drawing twenty-four mammals in twenty-four hours and in the process raised $800 for Defenders of Wildlife. With the help of several gallons of vanilla DP, she even managed to slam my “diabolical” curve-ball request out of the park. Go check out her awesome work!
- Entomologist, photographer and one-time Davisite, Alex Wild has launched an awesome ant-blog Myrmecos. Wild’s photography is truly amazing and has often made me want to chuck my camera off a cliff. Fortunately, since the camera doesn’t belong to me, there aren’t many cliffs in Davis. His blog may well drive me to lob my laptop into the Interstate though.
- Mechanical insect art by Mike Libby! Crazy…
- Tai’s tales of auspicious animal encounters reveals the patent grayness of my animistic sphere. But I saw an octopus! and cranes! and like, multiple scorpions some of which I held so cut me some slack.
- I was desperately hoping to take up the Schmitz et al. paper in the inaugural issue of Nature Geoscience and the broader issue of the Ordovician radiation and the growing impulse to invoke bolides as a causal agent for all dramatic biotic events… But, well we’re gonna have to wait for that.
So, here’s your homework – “What are the benefits and dangers of applying neoecology notions like disturbance ecology or island biogeography to evolutionary or extinction events in the fossil record?” Write a three to five page review of the issue including at least six primary references and one figure, due January 15th 2008.
okay, we’ll leave it at that, if I haven’t had cause or opportunity to apologize to you in person this year, I’m sorry. There’s always next year!
Okay, I’m going on record in defense of our favorite AP word-smith, science writer Seth Borenstein.
In a nice blogpost on Indohyus, [the sexiest new raoellid on the block] Brian takes Borenstein to task for some awkward animalian analogizing:
writer Seth Borenstein can’t seem to figure out just what Indohyus is. His confusion is apparent from the first line of the article;
It sounds like a stretch, but a new study suggests that the missing evolutionary link between whales and land animals is an odd raccoon-sized animal that looks like a long-tailed deer without antlers. Or an overgrown long-legged rat.
Borenstein scrabbles1 to lump Indohyus in with some modern animals in a feeble attempt to get people to understand the fossil find, but I can’t help but wonder if such a comparison does more harm than good.
As I noted in a comment on Brian’s blog however, Borenstein cribbed his ungainly comparison from the lead author on the Indohyus paper Hans Thewissen, at least in part:
“The earliest whales didn’t look like whales at all,” Thewissen said. “It looked like a cross between a pig and a dog.” They lost their legs and ability to walk on land about 40 million years ago, he said.
And the Indohyus? “A tiny little deer maybe the size of a raccoon and no antlers,” Thewissen said. He said it most resembles the current African mousedeer, which has a rat-like nose and “when danger approaches, it jumps in the water and hides.”
Sure, maybe it’s a misleading oversimplification to cast the cetacean ancestry debate as a war between the “racoon-deer campus” and the “hippo campus2.” Sure, trying to shoehorn every strange animal into this or that familiar category or combo of categories is a dubious (though longstanding and universal) habit. But, as long as we’re not ‘calling whale evolution into question’ hey, I’m pretty happy.
Sometimes, words just fail. Good thing we have Carl Buell. Check out Buell’s awesome reconstruction on Laelaps.
1 – Note the awesome verbing of the word “scrabble”.
2 – sorry.
Well, calling Charles Willson Peale a polymath may be rather generous. Then again, if I had run a failed saddle shop, painted some bossy white dudes, and created the first American Natural History Museum, I think I’d probably feel pretty worthy of the title. Anyway, when was the last time you went to a glass harmonica concert or whatever? [well, knowing microecos readers, it was probably last weekend]
At any rate, before we tossed his geriatric remains from the bell jar, I figured it was worth giving the bloke a proper post. Exhumation of the Mastadon [sic] (1806) (pictured above) remains probably the best American painting to date, though some of Richard Estes’ stuff comes close. That is, of course, ol’ Pealey himself in the jacket and slacks. Much, much more Peale info here.
microecos is a rotting peaty wreck.
