How Parasites Can Drive Ecological Relationships

18 06 2010

Good tidings and well-wishes!

As I’ve mentioned earlier, I read and thoroughly enjoyed Carl Zimmer’s excellent “Parasite Rex: Inside The Bizarre World Of Nature’s Most Dangerous Creatures” last February and have been meaning to post an article about one of the book’s most fascinating points ever since (I’ve just been procrastinating): namely, how the very life-and-death struggles between predator and prey as are often, little more than puppet shows.

More often than you might think, both parties involved are, in fact, driven by parasitic pilots.

Zimmer cites several examples of this most engaging phenomenon. However, by far the most interesting hails from the great American West.

Speaking of the wild west, this story comes with it’s own version of the good, the bad, and the ugly (though precisely who’s who is debatable as we shall see…): the curtain to the tale of the California horn snail (Cerithidea californica), the California killifish (Fundulus parvipinnis), and the various shorebirds of the Golden State’s ample coastlines.

What do these seemingly random animals have in common? A fluke by the name of Euhaplorchis californiensis.

The fluke in question.

Both the snails and the kilifish inhabit salty coastal marshes, and the latter of which naturally attract hordes of piscivorous birds as well. Avian feces inadvertently transport the eggs of E. californiensis, which serve as the primary dietary component of the California horn snail. When these eggs hatch, the flukes initially castrate the unfortunate mollusks before creating several generations of their own until, eventually, larvae (“cercariae”) burst from their initial host.

The Snail In Question

Following the 0nset of this exodus, the cercariae patrol their native salt marsh looking for killifish. Once they manage to happen upon these scaly critters, the parasites latch onto their gills and crawl ever deeper into the host’s body. Eventually, the cercariae follow a certain nerve which leads them directly into the unfortunate fish’s brain. Once there, rather than penetrating this most vital organ, these worm-like creatures merely congregate to form a thin, caviar-like layer atop it.

At this stage, the parasites must now await the consumption of their host by a predatory shorebird. Once this happens, the cercariae erupt from the fish’s stomach and flock to the fowl’s gut. In this new environment, E. californiensis steals nourishment from the new host’s digestive tract and deposits its eggs within the animal’s intestines, to be deposited whenever the bird defecates and, thus, recycling the process.

However, assuming that these parasitic organisms passively leave their lives and reproductive futures entirely up to chance would be a fatal mistake.

In an experiment conducted by ecologist Kevin Lafferty and his then-student Kimo Morris during the early nineties, the behavioral tendencies of 42 captive killifish were individually observed for days on end prior to the animals’ dissection in which the presence of E. californiensis would be confirmed or denied. According to Zimmer:

“What was hidden to the naked eye came leaping out of the data. As killifish search for prey, they alternate between hovering and darting around. But every now and then, Morris would spot a fish shimmying, jerking, flashing its belly as it swam on one side, or darting close to the surface. These might be risky things for a fish to do if a bird was scanning the water. And Morris’s vigil had revealed that fish with parasites inside them were four times more likely to shimmy, jerk, flash, and surface than their healthy counterparts. Since then, Lafferty has been working with a molecular biologist to figure out how the parasites make their hosts dance. They’ve found that the flukes can pump out powerful molecular signals, known as fibroblast growth factors, which can interfere with the growth of nerves. They could turn out to be the parasite’s Prozac[: an antidepressant drug which contains a molecule that acts as a neurotransmitter].”

(For those interested in reading an entire paper on the subject of parasitic brain manipulation in this instance, do go here!)

A Great Egret: one of the many bird species in question.

Some three weeks following Lafferty and Morris’ initial experiment, the pair decided to investigate the effects of this most curious relationship upon the local environment as a whole. Through a series of field tests, they discovered a fascinating unexpected result.

These shorebirds weren’t four times more likely to devour  infected killifish, but thirty times!

Although these flukes do take a slight physiological toll upon their avian hosts, the birds would have to exert a costly amount of energy to steer clear of infected fish (assuming they’d have any way of recognizing them); wasted energy that might prove fatal. Ergo, to these feathered beasts, the benefits of ingesting fluke-filled killifish vastly outweigh the costs.

The aforementioned fantastically large percentage thus begs a very intriguing question: “If this parasite didn’t exist, could populations of these birds survive if their food was thirty times more difficult to obtain?”

For those still unconvinced by the idea that parasites are more than mere hitchhikers and instead wield an enormous amount of influence upon their residential environments as a whole, let’s return to the horn snails for a moment. Prior to his investigations concerning the effects of E. californiensis upon killifish and birds. To once again reference “Parasite rex”:

“[These flukes] don’t quite kill their snails. In a genetic sense, the snails are indeed dead, because they can no longer reproduce. But they live on, grazing on algae to feed the flukes inside them. If the snails were truly dead, the algae they ate would be left for surviving snails to graze on. Instead, the flukes-as-snails are in direct competition with the uninfected snails…

Lafferty measured how the uninfected snails performed without parasitized snails competing with them. They grew faster, released far more eggs, and could thrive in far more crowded conditions. The results showed Lafferty that in nature, the parasites were competing so intensely that the healthy snails couldn’t reproduce fast enough to take full advantage of the salt marsh. In fact, if you were to get rid of the fluke, the snail’s overall numbers would nearly double. And this being the real world rather than a lab, that explosion would ripple out through much of the salt marsh ecosystem, thinning out the carpet of algae and making it easier for predators of snails, such as crabs, to thrive.”

If I’ve managed to pique your interest with these excerpts, I’d most heartily recommend checking out “Parasite Of The Day“: an exquisite blog run by some of the world’s leading parasitologists. If you’re anything like me, your mornings won’t be complete without it!

Cheers,

-Mark Mancini





Nectocaris Update

26 05 2010

Good tidings and well-wishes!

Last week, I leant some coverage to the bizarre little Burgess Shale creature Nectocaris pteryx. At the time, all of the publicly-available information about the species maintained that

A) Its known from but a single specimen.

B) Postcranially, Nectocaris was a sinuous, chordate-like creature.

However, shortly after my article was published, everyone’s favorite stuffed theropod pointed out that a pair of Burgess Shale scientists (The University Of Toronto’s Martin Smith & Jean-Bernard Caron) had argued that Nectocaris was, in fact, the earliest-known cephalopod and were working on a paper to this end. Evidently, the pair had stumbled upon NINETY-ONE additional specimens such as the one below:

That paper was released today, and the results have dramatically altered our perceptions of what this beast looked like. Ed Young of the brilliant blog “Not Exactly Rocket Science” has the scoop.

For those too lazy to click on the link to my earlier post, here’s a traditional reconstruction of Nectocaris as derived from the genus’ first and, for several decades, solitary specimen:

And here’s the updated reconstruction based on this wealth of newfound material:

I think it’s fairly obvious to say that this isn’t merely some miniscule alteration: it radically changes everything we thought we knew about this creature’s anatomy and phylogeny. To quote Mr. Young:

“Around four centimetres in length, Nectocaris had a soft, flattened, kite-shaped body with two fins running down its sides. Its small head was adorned with two long tentacles and two stalked eyes. Unlike the compound eyes that were common among Cambrian animals, probably had the camera-like structure that modern cephalopods use. From its neck protruded a flexible funnel, which opened into an internal cavity containing pairs of gills.

The funnel lay behind some of the earlier confusion about Nectocaris. In the original specimen, it was flattened so that it looked like a shield-like plate behind the eyes, reminscent of a crustacean’s body armour. The new specimens put paid to that interpretation. The structure is clearly a funnel, similar to those used by modern cephalopods. Nectocaris probably used it to swim the same way, giving it an extra boost of jet propulsion to complement the beating of its large fins.”

The homogeneous lack of shells throughout the newfound Nectocaris specimens have shattered the notion that cephalopods evolved from Monoplacophorans: an assertion which largely rested upon the fact that the earliest known representatives of this tentacled group had previously been the nautiloids. Evidently, the shells which graced several groups and species of subsequent (and current) cephalopods evolved independantly.

However, not every gap has been filled in assigning Nectocaris to this new role: none of the fossils appear to display the intimidating beak-like mouth and horny tongue (known scientifically as the ‘radula’) of squids, octopi, and their kin remains, as far as the authors can ascertain, absent from N. pteryx. The radula is of particular importance due to its presence in nearly every group of modern mollusks and has hence become a uniting feature.

Regardless of what Nectocaris’ true relations may be, this news provides yet another example of how fossilized species with which the scientific community feels it’s somewhat familiar can drastically suprise its members almost instantaneously by way of new discoveries (or even, in some cases, a second trip through the archives).

A POINT TO CONSIDER: How much time will elapse before PZ Meyers jumps all over this story?





Burgess Shale Extravaganza: Canadia

21 05 2010

Good tidings and well-wishes!

I’ve saved the concluding entry in this week-long diagnosis of Burgess Shale weirdos for what I consider to be one of the most extravagant and yet under-appreciated denizens of this most paleontologically vital of fossiliferous congregations: the 3-centimeter annelid Canadia spinosa.

The bizarre, vaguely feather-shaped extensions of the creature’s anatomy as shown in the previous photograph are in fact an innumerable series of short, rigid bristles scientifically known as “setae”. More specifically, they can be classified as “notosetae”: these are setae which are rooted in an animal’s dorsal lobes. These rather “showy” contraptions cover essentially the entire dorsal surface of Canadia. In famed Burgess paleontologist Simon Conway Morris’ book entitled “The Crucible Of Creation: The Burgess Shale And The Rise Of Animals” (which was largely written from the perspective of a time-traveling scientific research team, hence the heavy editing I’ve provided), he writes:

“Each bundle [of notosetae overlaps] the one behind it, so as to give a tile-like covering to the upper surface of the body. There can be little doubt that this entire arrangement [was] primarily protective. The neuropodia [or "ventral branches"], in contrast, are much more lobe-like and strongly muscular. Each neuropodia bears a prominent podium of [setae], and it is on these structures that [the creature walked]…[theoretically] by a series of locomotory waves passing along the neuropodia. By precise coordination each neuropodium is first placed on the seabed and then pushed back so that the [notosetae] act as levers to push the animal forwards. Finally, at the end of the stroke the neuropodium lifts the [setae] clear of the sediment and swings them forward in preparation for the next shove against the sea floor.”

In addition to hypothetically providing a degree of protection, the notosetae may have enabled Canadia to swim were they rhythmically beaten while cruising above the sea floor.

Canadia‘s gut was straight and was capable of anteriorly extending from the main body to form a proboscis of sorts. Along with the frequent presence of sediment in the beast’s gut, this digestive setup has given rise to the hypothesis that Canadia was a detrivore. The function of the anterior pair of tentacles is unknown, though they likely assisted the animal’s sensory capabilities.

I’ll close this article with an intriguing idea championed by Conway Morris’ aforementioned volume: that Canadia may in fact be that most elusive of Cambrian fauna: a relative of WiwaxiaWere this true, it would greatly disambiguate the spiny little eccentric’s incomparably vague phylogeny. Consider the following passage:

“When the [setae] is placed under the microscope, it is seen to have a microstructure very similar to that observed in Wiwaxia. Evidently there is some evolutionary connection between Canadia and Wiwaxia.”

Furthermore, Conway Morris notes that the ventrally-situated gills of Canadia strongly resemble those of modern molluscs, which persuasively insinuates a kinship between the genus and the mollusca phylum as well. Hopefully, additional discoveries will yield a plethora of new information concerning this functional morphology, evolution, and taxonomic affiliations of most engaging organism.

May the fossil record continue to enchant us all!





Burgess Shale Extravaganza: Aysheaia

20 05 2010

Good tidings and well-wishes!

Although many self-described “hard-core” scientists refuse to acknowledge it, popular culture exerts an appreciable influence upon virtually every discipline of science imaginable. Dinosaurian afficionados are well aware of Gary Larson’s “The Far Side” leading to the anatomical term “thagomizer” (which, for those ill-versed in paleo-jargon, describes the unique  spike arrangements on the tails of stegosaurs), guitarist Mark Knopfler’s namesake theropod Masiakasaurus knopfleri, and, of course, the “Harry Potter”-inspired pachycephalosaur Dracorex hogwartsia.

Dinosaurs, however popular, are far from the sole examples of this trend, as evidenced by the Burgess Shale denizen Aysheaia sp. whose genus name derives from the Ayesha mountain peak which, in turn, was named for Aysha: a sorceress and the “title” character of Rider Haggard’s 1905 novel “She: A History Of Adventure”. As is the case with its literary namesake, the simultaneously “alien” and “familiar” appearance of the two-inch Aysheaia is, as with many Burgess Shale residents, quite spell-binding (how’s that for a labored segue?).

According to Stephen Jay Gould’s “Wonderful Life”:

Aysheaia has an annulated, cylindrical trunk, with ten pairs of annulated limbs attached at the sides near the lower surface and pointing down, presumably for use in locomotion. The anterior end is not separated as a distinct head. It bears a single pair of appendages, much like the others in form and annulation but attatched higher on the sides and pointing laterally. The terminal mouth (smack in the middle of the front surface) is surrounded by six or seven papillae. The head appendages bear three spinelike branches at their tip, and three additional spines along the anterior margin. The body limbs end in a blunt tip carrying a group of up to seven tiny, curved claws. Larger spines emerge from the limbs themselves. These spines are absent on the first pair, point forward on pairs 2-8, and backward on 9-10.”

It should be noted that the limb-like appendages of Aysheaia are not true legs but can best be termed “lobopods”. Despite the fact that each lobopod is divided into a series of transverse rings, these are not to be mistaken for the series of joints which compose the legs of arthropods. In life, these lobopods would have contained a thick, muscular core surrounded by a fluid-filled cavity. This setup would have served as a hydraulic pump of sorts designed to enable locomotion.

Interestingly, a large percentage of Aysheaia specimens are found in association with the remains of sponges–an essentially nonexistent occurence elsewhere within the Burgess faunal roster. This has given rise to the well-accepted hypothesis that Aysheaia may have fed and dwelt upon these most primitive of animals. The idea is granted additional credibility when one considers the uselessness that the animal’s many claws would have likely served on the muddy floor of the basin. However, these spikes could have easily been employed for the purposes of scaling sponge colonies. Furthermore, it’s logical to conclude that Aysheaia‘s preserved anatomy insinuates no recognizable form of defense: a dire predicament which could have easily been averted were the creature to seek refuge within its (theoretical) spongy home.

As for Aysheaia‘s phylogenetic relationships, most paleontologists acknowledge that the beast bears a strong overall resemblance to the modern velvet worms (phylum Onychophora), although whether or not the genera should be considered a member of their phylum remains the subject of debate.

May the fossil record continue to enchant us all!





Burgess Shale Extravaganza: Amiskwia

20 05 2010

Good tidings and well-wishes!

NOTE: Contrary to the assertions of WordPress, this article was in fact posted on the 19th.

The soft bodied and rather delicately-built Amiskwia sagittiformis is a superb example of the conflict which often arises when a fossil is subjected to exceptional preservation and a debatable amount of deformity. The soft composition and meager proportions of Amiskwia and its kin prevent their fossil record from becoming remotely extensive. Hence, we may never know the degree to which geologic forces have altered the appearance of this superficially worm-like animal. Nonetheless, enough information has been gathered to make a few tentative educated guesses concerning its lifestyle and possible taxonomic affiliations.

Though the statement may sound comical, at a full inch in length, Amiskwia was a comparatively large inhabitant of the Burgess Shale and the elder Maotianshan Shales . This considerable size appears to have come at the expense of abundance, with a mere eighteen specimens of this peculiar genus having been found in the former deposit as of this writing.

Amiskwia‘s entire body is dorso-ventrally compressed. Its head sports a pair of ventrally-situated tentacles, just behind and between which lies an ovular mouth. Though the creature’s “trunk” is unsegmented, it does contain a pair of lateral fins which are unsupported by any sort of stiffening device: the same is true for the caudal fin which comprises the beast’s tail. The trunk and caudal regions of Amiskwia‘s anatomy appear to have been quite muscular: a piece of evidence which supports the hypothesis that Amiskwia may have been a pelagic (free-swimming) organism, which would also help to explain its aforementioned rarity in the formerly muddy Burgess basin.

Intriguingly, the internal anatomy of Amiskwia is also relatively well preserved, as partially displayed by the following fossil specimen:

According to the Smithsonian Institution’s official page on the species:

“Note that in the fossil preparation the head shows a highly reflective area (cerebral ganglia? [aka: the bilobed 'brain' of many modern worms and arthropods])… The broad light area running along the trunk is the gut, while the narrow linear structures along the trunk may be traces of blood vessels and a nerve cord.”

 

Note the rather conspicuous pair of bulb-like organs in the head of this Amiskwia reconstruction: this is the artist's depiction of its cerebral ganglia.

The phylogenetic relationships of Amiskwia are a matter of some debate. However, the general consensus amongst Cambrian paleontologists is that while the genus exhibits characteristics akin to those of the chaetognatha and nemertea. it cannot be scientifically accomodated by either group.

May the fossil record continue to enchant us all!





Burgess Shale Extravaganza: Canadaspis

18 05 2010

Good tidings and well-wishes! 

In yesterday’s Burgess Shale post, I gave mention to the fact that, in the words of Cambrian paleontologist Simon Conway Morris, “Current research is showing that a number of species from the Burgess Shale cannot reasonably be accommodated in any extant phylum”. While this fact greatly assists the incomparable intrigue of this bizarre and delightfully unique collection of organisms, it often serves as a simultaneous source of irritation for scientists and enthusiasts alike. Perhaps the most infuriating example of this taxonomic ambiguity is embodied by the case of Canadaspis sp., a creature long believed to have not only been a crustacean, but a primitive malacostracan: a retrospective image shattered by subsequent research and debate. 

Canadaspis perfecta (the most abundant Burgess Shale species) specimen.

Although this blog has historically covered phylogeny before anatomy and functional morphology, the confusion surrounding the former discipline with regard to this particular animal forces me to abandon this trend here. Instead, I’ve opted to commence with the general description. 

C. perfecta reconstruction.

In very general terms, the creature’s appearance has been described as “shrimp-like”. Its head, along with most of its “trunk”, is covered by a 2cm-long hinged, bivalved carapace (the entire animal was a mere 3 cm in length). This shell, along with the rest of Canadaspis‘ exoskeleton, is composed primarily of chitin, as is the case with all arthropods. The abdomen (rear section) sports several segments with a spine-flanked telson

 

The thorax (mid-section) is a matter of considerable debate. Some paleontologists, such as Derek Briggs, have argued that this portion of Canadaspis‘ anatomy bears eight segments whilst several of his colleagues maintain that it actually houses ten segments. This academic difference of opinion is significant because the former interpretation would strongly assist any effort to place Canadaspis within the phyllocardia subclass of the Crustacea. A related point of disagreement concerns the following matter: living phyllocardians maintain a 2:8 ratio of limbs anchored on the posterior head and thorax respectively, yet the arrangement is somewhat vague in most fossil specimens. 

 

The beast’s head displays a pair of stalked eyes along with a pair of anteriorly-projecting antennae. Unlike those of modern crustaceans, these antennae are uniramous, meaning that they exist as two separate sets of segments (alliteration unintended) rather than two branched sets united near the base as in extant lobsters, crabs, shrimp, and kin (this setup is scientifically referred to as “biramous”). 

A C. perfecta is snared by an Anomalocaris.

It should be noted that Canadaspis enjoys a far greater fossiliferous range than most Burgess shale genera, having also been unearthed in Utah and, most interestingly, in the older Chengjiang lagerstatte of China’s Yunning Province where it is represented by C. laevigata (which may be synonymous with C. eucalla, another species described from the formation). The best-known and most well-preserved species, however, is the Burgess’ C. perfecta 

 

Having discussed the controversial and relatively cryptic anatomy of this frustrating little species, the time has come to examine its functional morphology. The presence of a slit in what is believed to be the animal’s gut suggests that Canadaspis may have fulfilled its dietary needs by devouring organic material in ingested sediment. This geological bedding may have easily been shuffled into the creature’s maw by virtue of Canadaspis‘ gill flaps attached to each limb: these may also have been used to enable swimming. Furthermore, C. perfecta is frequently found in association with the miniscule trilobite Ptychagnostus which is often found within the rounded head shield of Canadaspis and a few other arthropods, suggesting that they may have been a relatively common prey item. Much more theoretically, Andrew Parker has suggested that Ptychagnostus may have even been a cranial parasite of sorts, though there appears to be no way of validating (or even expanding upon) this interpretation. 

 

On a final note, although Canadaspis can no longer be comfortably placed within any extant crustacean group, the fact that it was almost certainly allied with the subphylum renders its classification considerably less mysterious than those of a great many Burgess Shale residents. Unfortunately, many people seem to invariably assume that “mysterious” is synonymous with “interesting” and, consequently, that any degree of familiarity associated with a given object or phenomenon robs it of intrigue. We would all do well to consider Stephen Jay Gould’s view on the subject: 

Canadaspis is both a key and an anchor to the Burgess story, a creature every bit as important as any of [its] weird wonders. Suppose that every Burgess animal were a bizarre denizen of a lost world. What then would we make of the assemblage? A failed experiment, a washout, a first attempt totally bypassed by a reconstituted modern fauna, and therefore offering no clues and no connection to the origin of later life. But the presence of Canadaspis, and other creatures of [relatively] modern design, suggests a different and more enlightening view. The Burgess fauna does include modern prototypes, and, in this key respect is an ordinary Cambrian fauna; but the vastly broader range of designs that disappeared may reveal the most important of all patterns in life’s early history.” 

May the fossil record continue to enchant us all!





Burgess Shale Extravaganza: Nectocaris

17 05 2010

Good tidings and well-wishes!

NOTE: Much of the information contained in this article has been effectively rendered out-dated by a very recent discovery. Click here to find out why.

As promised, TTT is now proud to present a series of articles concerning its author’s favorite Burgess Shale oddities. Anyone familiar with the dynamic formation has doubtlessly run across the following conclusion described by reknowned Cambrian paleontologist Simon Conway Morris: namely that “Current research is showing that a number of species from the Burgess Shale cannot reasonably be accomodated in any extant phylum”. In 1973, Conway Morris composed a series of papers describing a bizarre collection of five Cambrian oddities ecased within the local rock prior to his doctoral thesis. These exceptional oddities are as follows: Nectocaris, Odontogriphus, Dinomischus, Amiskwia, and Hallucigenia. Though this week-long event won’t lend its coverage to each of these admittedly very deserving candidates, I’ve nevertheless elected to kick things off with the former member of this motley congregation: Nectocaris pteryx, a sinuous chimaera of a beast which for all the world resembles a cross between an arthropod and a chordate.

Any attempt to disambiguate the affiliations of this peculiar critter are gravely unassisted by the fact that Nectocaris is, to date, known from but a single specimen. Although I’ve most regrettably been unable to upload an image of the fossil in question, I’d advise anyone interested in viewing it to consult this link. However, as is often the case with Burgess Shale organisms, what the fossil record of Nectocaris lacks in abundance, it makes up for in anatomical clarity.

From this solitary example, the scientific community has been able to erect a reasonably-complete reconstruction of how this fascinating animal looked. As alluded in the introduction, the most striking feature of Nectocaris is the coupling of its vertebrate-like tail and body with its very arthropod-esque head and “neck”. As depicted in the above pair of reconstructions, the animal’s head sports a pair of short, forward-projecting appendages. While these structures may conjure thoughts of crawdads and other crustaceans, their lack of joints renders them decidedly more primitive. The posterior end of the head is covered by an ovular shield which, according to some experts, may have been bivalved. Similarly debatable is whether or not Nectocaris‘ eyes rested upon stalks, although most paleo-artists appear to have arrived upon the affirmative conclusion in this regard.

All this being said, Nectocaris lacks the single most commonly cited defining characteristic of the arthropoda phylum: jointed appendages. In place of these, evolution has elected to grant Nectocaris a laterally-compressed body composed of approximately forty segments. This lengthy form is dorsally and ventrally draped by a pair of fins which, as noted by Conway Morris himself (along with Stephen Jay Gould), strongly resemble those belonging to the Actinopterygii (or “ray-finned”) class of fish.

According to Gould’s excellent book entitled “Wonderful Life: The Burgess Shale And The Nature Of History” (which, not suprisingly, will be referenced quite routinely during the course of this event), the following features of these fins insinuate some sort of affiliation (or, possibly, a case of convergent evolution) with modern chordates:

-While arthropod limbs are almost exclusively connected internally, a dark, slight, filmy layer of some dark structure appears to externally unite the parallel series of rays into a single “fin”.

-Arthropod appendages sprout from a lateral base with near invariability. This is contrasted by Nectocaris’ dorsal and ventral fin set.

-Arthropod bodies are constrained by a general rule which prohibits the attatchment of multiple appendages to each individual segment. Nectocaris‘ fins contain an average of three stiffening rays anchored in each bodily division.

A brown Nectocaris and a pair of green Marrella evade the grasp of the enormous, predaceous Anomalocaris. Note the bluish Pikaia, one of the earliest-known chordates, in the upper right-hand corner. Painting by Peter Bond.

Whatever the phylogenetic and taxonomic affiliations of Nectocaris may in fact be, the eccentric creature reminds us quite vividly that although paleontological science has greatly expanded our view of life’s historical saga, a great deal remains to be learned.

May the fossil record continue to enchant us all!

UPDATE: Be sure to check out the ‘comments’ section for a very intriguing hypothesis concerning Nectocaris‘ evolutionary affiliations.








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