But Is It Art?

Just a footnote to the last post - I realise a number of people who read this live in America (you poor, poor, sorry people) and I don't know how familiar Ab Fab is to American audiences. So if there are any of you who haven't seen the segment I referred to, here's the part quoted courtesy of YouTube:



Of course, as YouTube has been blocked at uni to stop students from simply downloading stuff all day, and I live in one of the sections of Perth where we can only have a dial-up connection at home because the phone-lines can't carry broadband, this took half an hour of buffering to check I had the right one-minute segment. I hope you appreciate it.

Art is Science, Science is Art

Guardando nel suo Figlio con l'Amore
che l'uno e l'altro etternalmente spira
lo primo e ineffabile Valore
quanto per mente e per loco si gira
con tant' ordine fé, ch'esser non puote
sanza gustar di lui chi ciò rimira.

Gazing on His Son with the Love
the One and the Other eternally breathe forth,
the inexpressible and primal Power
made with such order all things that revolve
that he who studies it, in mind and in space,
cannot but taste of Him.

---Dante Alighieri, Il Paradiso, Canto X, English translation by Robert & Jean Hollander, via the Princeton Dante Project.

I have probably been remiss in not mentioning that this week (since Saturday, in fact) is National Science Week in Australia. To mark the week, I was considering presenting daily posts on five of the foundations that I think underly the concept of science - Mathematics, Language, Art, Enquiry and Skepticism. Obviously, this didn't end up happening - if nothing else, I'm not really knowledgeable enough to comment on most of them (it's probably better I leave such things to people such as John Wilkins who are more likely to actually know what they're talking about). I would like to present one of those ideas, though, flawed as my reasoning might be - the relation between Science and Art.

In that incredible human ability to devise false dichotomies that I've spoken of before, people often imagine "the Sciences" and "the Arts" as two distinct entities, often imagined to be at odds with each other in some way. As with so many other such distinctions, this is complete rubbish. For all that they may differ in method, the ultimate aims of science and art are practically identical - the investigation and description of the world in which we find ourselves living. Interest in either field engages similar qualities - creativity, the desire to investigate and challenge boundaries, and ultimately the desire to communicate about one's findings/products with others.



Art, like Science, is a difficult concept to define, and one question that tends to come up repeatedly is how an empty room with a flickering light bulb, a statue of the Virgin Mary ensheathed in a condom, or a couple of buckets of paint dribbled randomly over a canvas by Jackson Pollock qualifies as "art". Part of the explanation is that there is more to a work of art than simply the piece itself. The movie Memoirs of a Geisha refers to such an artwork - "At the temple, there is a poem called "Loss" carved into the stone. It has three words, but the poet has scratched them out. You cannot read Loss, only feel it." The viewer's experience of the artwork is as integral to that work as the physical object itself. In the Kurt Vonnegut novel Bluebeard, the artist Rabo Karabekian keeps his last and most spectacular artwork locked up in a barn, concealed from all others until it is only revealed after his death. The obvious question is whether, had it never been found, the piece would have even qualified as art as all. I would also cite the example of an episode of Absolutely Fabulous in which Edina decides to invest in art in order to establish a legacy. At the gallery, she makes it clear that she has no interest in the artistic intention of the works, only in their monetary value, so the gallery manager immediately sells her a pile of the more rubbishy abstract works - a pile of planks of wood lying against the wall, a stack of empty jam jars, a mobile constructed of coat-hangers. Later, she attempts to explain the pieces to Patsy (really, only reading out what it says in the brochure): "This is the materialisation of the psychotic's dream deciphered by a clairvoyance... hangers, it's hangers". Without the viewer engaging the artwork as an artwork, it ceases to be one - the pile of coat-hangers is merely a pile of coat-hangers. Similarly, the ultimate value of science lies in communication. Research that is conducted in private and never made public might as well have never been done at all. Just as an artist prepares their work and presents it for the appreciation and criticism of their peers, so a scientist prepares and presents their publications.

Last week I referred to Ernst's Haeckel's luxurious 1899-1904 work Kunstformen der Natur ("Artforms of Nature"), which deliberately blurred the boundary between a scientific and an artistic work. As reflected in the quote at the top of this post, one of Western Civilisation's most enduring works of Art, La Commedia of Dante Alighieri, stressed the importance of rational enquiry as long ago as the 1300s. I have spoken to a number of fellow scientists - both professional and amateur - who have described their interest in reading firsthand the works of past researchers such as Owen, Cuvier, Darwin, Cope and Marsh. In many cases, the practical significance of these works has arguably decreased over time, as their premises have been improved or superceded by later workers, but their significance and interest as historical compositions turns them into artworks in their own way.

Amaurobioidea: Rummaging through a Wastebasket

A representative of the strikingly-coloured Nicodamidae from Australia. Photo by Nick Monaghan. While such spiders were previously identified as Nicodamus bicolor, there are no less than 23 species in seven genera that have previously been included under that name.

One term that you may come across in discussions of phylogeny is the concept of a "wastebasket" taxon. As the name suggests, a wastebasket taxon is one into which authors tend to throw everything that they can't really deal with. Often, a wastebasket will include the members of a group that are relatively unspecialised, often primitive, and united less by their shared characters than their lack of distinct features to connect them to one or another of the specialised subgroups that the author may recognise within the parent group. Phalangodidae among short-legged harvestmen, Sylviidae among passerine birds and Perciformes among spiny-finned fishes are all examples of taxa that have become wastebaskets in the past. Some wastebasket taxa are explicitly established as such, like the 'Deuteromycota' that included asexual fungi before techniques were developed that made it significantly easier to relate asexual and sexual fungal taxa. More often, though, a taxon originally based on a certain combination of features will develop into a wastebasket over time as phylogenetic studies show that the original basis characters for that taxon represent plesiomorphies (ancestral characters). This week's highlight taxon, the spider superfamily Amaurobioidea, perhaps belongs to the latter group.


Tegenaria gigantea (Agelenidae). Photo from Wikipedia. Agelenids build funnel-shaped webs and are apparently often called some variant of "funnel spiders" in North America, but such names are likely to cause confusion here in Australia with a certain notorious mygalomorphs. Some species of Tegenaria such as the hobo spider are also known for being toxic, but nowhere near as toxic as the Australian funnel-web.

In an earlier post, I included a quick overview of basal spider phylogeny, going as far down as the clade Araneoclada that unites those spiders that have only a single pair of book lungs (ancestrally, at least - many families of Araneoclada have lost the book lungs entirely, or evolved tracheae in their place). Members of the Araneoclada are further divided between the Haplogynae and the Entelegynae, originally based on the presence (Entelegynae) or absence (Haplogynae) in females of paired copulatory ducts opening on a sclerotised plate called the epigyne. While the absence of such ducts in the Haplogynae is obviously a primitive character and no longer regarded as uniting them, the group has funnily enough been supported as monophyletic based on a number of other characters (except for a small number of 'haplogyne' taxa that are phylogenetically entelegynes) (Coddington & Levi, 1991). However, the Amaurobioidea belong to the Entelegynae, which is by far the larger of the two clades. Within the Entelegynae, the primary division was long based on whether or not a species possessed a cribellum, a plate-like structure among the spinnerets that bears hundreds of tiny silk-producing spigots. As these spigots exude silk simultaneously, the spider uses a specialised arrangement of bristles on the fourth pair of legs to weave them together to form a woolly thread (see here for a more detailed description). Because this woolly thread is composed of multiple tangled strands, it can effectively entangle prey such as small insects that get caught among the strands. Unfortunately, as knowledge of entelegyne spiders improved it became clear that possession of a cribellum did not define a phylogenetically coherent group. A number of cases were identified of pairs of taxa clearly related by other characters in which one taxon possessed a cribellum and the other did not. The eventual conclusion was that the cribellum was an ancestral character for the Entelegynae (as also supported by its presence in one haplogyne family, the Filistatidae) that had been lost on numerous occassions.


Ctenus floweri (Ctenidae), from Singapore. Photo by David Court. Ctenids are active hunters.

In general, the Amaurobioidea included cribellate spiders with unbranched abdominal median tracheae, as opposed to Dictynoidea with branched abdominal median tracheae (Coddington & Levi, 1991). Families that have been assigned to Amaurobioidea include (among others) Amaurobiidae, Agelenidae, Ctenidae, Amphinectidae and Nicodamidae, but relatively little unites these families. Most of them are generally ground-dwellers (which may explain the common name of one of the best-known members, the hobo spider Tegenaria agrestis). Many members build small sheet-webs, but others are active hunters. Both the characters referred to above have since been shown to represent plesiomorphies of larger clades, with the alternative conditions arising multiple times. The phylogenetic analysis of entelegyne spiders by Griswold et al. (1999) found the 'Amaurobioidea' to fall within a clade that was sister to the clade including the orb-weavers, but the same clade included the Dictynoidea and Lycosoidea (wolf spiders and such) nested within 'amaurobioids'. Indeed, not even the type family of Amaurobiidae was monophyletic, with some members closer to the lycosoids while others were closer to the agelenoids. The Amaurobioidea, it seems, was a bust.

Coming up - science and art, whether taxonomy is science, why family names are so awful, micro-spiders, and Parapseudoleptomesochrella almoravidensis.

REFERENCES

Coddington, J. A., & H. W. Levi. 1991. Systematics and evolution of spiders (Araneae). Annual Review of Ecology and Systematics 22: 565-592.

Griswold, C. E., J. A. Coddington, N. I. Platnick & R. R. Forster. 1999. Towards a phylogeny of entelegyne spiders (Araneae, Araneomorphae, Entelegynae). Journal of Arachnology 27: 53-63.

Get Kunstformen!

As a corrolary of preparing the last post, I also discovered that a scan of the entirety of Haeckel's Kunstformen der Natur on the BioLib site is available here. Be warned, though - that link leads directly to a file some 130 Mb in size, so only click on it if you really want it. Not to mention the significant amount of potentially productive time lost as you sit gazing stunned at Haeckel's spectacular artworks. Check out the dinoflagellates on page 131, the octocorals on page 145, the radiolarians on page 182, the demonic boxfish on page 182... hell, almost any of the plates will do. Though I have to admit that some of the things on page 403 are a little divergent from reality.

E Pluribus Unum

For many people, the name "Ernst Haeckel" is most associated with slightly dodgy illustrations of vertebrate embryos that have doomed his memmory to be quote-mined by people with an agenda to push for all eternity. For others, though, the epitome of Haeckel's work lies in the many spectacular illustrations of invertebrates and protozoa he produced in such works as his reports on the biological material collected by the HMS Challenger expedition, and his 1899-1904 Kunstformen der Natur ("Artforms in Nature"). With their awe-inspiring detail and spectacular presentation, the plates he produced are more than just technical illustrations, they are true works of art. Perhaps among the greatest of his productions were the plates of siphonophores, an example of which is shown above. Baroque tentacled horrors, they loom out of the page threatening to engulf Dunwich. I wouldn't be able to tell you whether Lovecraft had ever seen one of Haeckel's illustrations to inspire him in his descriptions of the twisted hybrid offspring of Yog-Sothoth, but the resemblance is uncanny.

Siphonophores are planktonic cnidarians (the group that includes corals and jellyfish), distantly related to hydras (a good online reference on siphonophores has been put together by Casey Dunn). The most familiar member of the group is Physalia, the Portuguese man of war (so-called because of a supposed resemblance to that form of ship), but on the whole Physalia is not very typical of the order. All siphonophores are colonial, in their way - incomplete budding leads to the production of a colony of generally large numbers of metabolically interconnected zooids that are developmentally homologous to the more independent polyps of other cnidarians. However, the individual zooids of siphonophores are each highly specialised for separate divided functions such as feeding, reproduction or motility, meaning that siphonophore zooids are incapable of living independently of the colony. Perhaps more than any other group of organisms, the siphonophores challenge the question of what defines an individual or a colony, which has led to their description as "superorganisms".

Siphonophores have been divided into three main groups, the Cystonectae, Physonectae and Calycophorae, but the phylogenetic analysis of Dunn et al. (2005) found calycophores to be nested within physonects, the two together forming a clade they named the Codonophora. Cystonects (which include Physalia) form the sister-group to the codonophores, and share a colony morphology characterised by a division between a terminal pneumatophore (float) and the siphosome, the region of the colony containing feeding and reproductive zooids coming off a central stalk (in Physalia the central stalk is relatively short, but other siphonophores will have exceedingly long colonies). In the "physonects", the pneumatophore and siphosome are separated by the nectosome, a region of generally bell-shaped zooids called nectophores specialised for motility. In the calycophores, the pneumatophore has been lost and the colony is composed of the nectosome and siphosome. The illustration at the top of the post represents the physonect Physophora hydrostatica - the pneumatophore is the bulb-shaped structure at the top, with the zooids of the nectosome between the pneumatophore and the tentacle-like structures representing the top of the siphosome. These latter structures are not actually tentacles (the tentacles are the filaments radiating from the siphosome) but palpons, zooids whose function remains unknown but has been suggested to be related to excretion or defense. Underneath the palpons are the gonophores, the reproductive zooids, with separate male and female forms (males and females may both be present in a single colony, or there may be colonies of separate sexes). The large funnels like the horn of an old gramophone are gastrozooids, the feeding individuals. The clubbed side-branches on the trailing tentacles are tentilla, and contain concentrations of nematocysts for capturing prey. Most codonophores (but not cystonects) also have shield-like gelatinous bracts protecting the siphosome. Cystonects also have structures called gonodendra, which are concentrations of gonophores, palpons and also specialised nectophores that can propel a detached gonodendron through the water. Many codonophores are bioluminescent - the bracts may contain luminescent cells, and at least one member of the genus Erenna has flashing red tentilla that probably function as lures. The Physonecta illustrated above has only one iteration of the siphosome, but in other forms (such as the one illustrated below in another Haeckel plate) the clusters of palpons, gastrozooids and gonophores may form iterative elements that repeat continuously down the growing stem.



Despite what can only be described as their inherent coolness, siphonophores as a group are poorly known. Like other planktonic cnidarians, their gelatinous structure makes them quite frail and difficult to collect. The entire colony may be only loosely connected by the slender stem, such as in the example just above. Some siphonophores reach spectacularly large sizes - species of Apolemia may be more than 30 m in length, yet only a few centimetres in diameter. Attempts to net such specimens using conventional means would be lucky to retrieve anything more than disassociated mush.

REFERENCES

Dunn, C. W., P. R. Pugh & S. H. D. Haddock. 2005. Molecular phylogenetics of the Siphonophora (Cnidaria), with implications for the evolution of functional specialization. Systematic Biology 54: 916-935.

Haeckel, E. 1899-1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig & Wien.

It's Baaack!

After a brief hiatus, the palaeontology blog carnival The Boneyard has returned and can be found at Laelaps. But take care - Amphicyon is guarding it...

Sacred Monkeys

Hanuman langurs - photo by Kamal Kumar Dua. Though identified on the source site as Semnopithecus entellus, this taxon has been divided between up to seven species in recent publications.

Todays' Taxon of the Week is the primate genus Semnopithecus. Once again, that's a sentence that's a bit easier to glibly write than it is to define. Semnopithecus includes the langurs, and together with the surelis (Presbytis) and leaf monkeys (Trachypithecus) forms a generally-accepted clade within the Colobinae, a group that also includes the colobus and odd-nosed monkeys and is characterised by a number of adaptations to a higher proportion of leaves in their diet than most other primate groups - most notably, a division of the enlarged stomach into an upper neutral region and a lower acid region, with leaves being broken down by fermenting bacteria in the upper region. Within the langur clade, however, there has been disagreement on the best way to treat the three subgroups taxonomically. Some authors have included all three groups in Presbytis, others have restricted Presbytis to the surelis and combined the langurs and leaf monkeys as Semnopithecus, while others have recognised three separate genera. Because this is purely a question of ranking and there doesn't seem to be any disagreement that langurs and leaf monkeys are more closely related to each other than either are to surelis, there is no "correct" answer here. For the purposes of this post, I'm going to treat langurs and leaf monkeys as two subgenera of Semnopithecus, for no reason whatsoever other than it allows me to cover both groups, though it is worth noting that the phylogenetic analysis of Osterholz et al. (2008) did not confirm the monophyly of Trachypithecus relative to Semnopithecus sensu stricto.

No consensus seems to exist on the number of species within Semnopithecus. The langurs may represent as little as one or as many as seven species, depending on how the various populations around the Indian subcontinent are divided up. The leaf monkeys are even worse - Trachypithecus is the largest generic grouping in the Colobinae, and includes more than ten species scattered through south-east Asia. Many leaf monkey populations are poorly studied and species boundaries within the group are often unclear. Osterholz et al. divided Trachypithecus into fifteen species in five species groups as apparently recognised by Groves (2001) (which I haven't read), one of which (the Semnopithecus vetulus group with two species found in Sri Lanka and southernmost India) they found to cluster polyphyletically within Semnopithecus sensu stricto and transferred into the latter genus as a result. The Trachypithecus pileatus group, found on the boundary between the Indian subcontinent and south-east Asia, clustered with Semnopithecus in analysis of mitochondrial DNA but with Trachypithecus in analysis of Y chromosome data, leading Osterholz et al. to suggest the possibility of ancient hybridisation in the origin of the group.


The golden langur (Trachypithecus geei). Photo from bhutanonline.net.

Most leaf monkeys live in small groups of about six to eighteen individuals (Brandon-Jones, 1984). Compared to some other primates, colobines apparently show relatively little social interaction among members of a troop (though still being fairly social compared to many other mammals, of course), which Brandon-Jones (1984) suggested may be an indirect consequence of their diet. Almost all colobines include a certain proportion of young leaves in their diet, but few can eat a significant amount of mature leaves. As this is fairly low-nutrition fare, colobines must spend a higher proportion of their time feeding than other primates, while the scattered distribution of young shoots requires individuals to spread themselves fairly thinly through a foraging site. Most colobines do eat fruit and other plant parts in addition to leaves, and langurs have a fairly varied diet that also includes such things as insects, roots, gum and sap. Indeed, langurs are noted for being able to readily stomach toxin-bearing foods such as Strychnos fruit that other herbivorous mammals would find inedible or even fatal. Langurs may be found in larger groups than leaf monkeys, with up to seventy individuals recorded in a troop (the largest size referred to by Brandon-Jones is a group of 120 individuals, though this may have been a temporary cluster of troops seeking water rather than a single troop). This may reflect their more varied diet, and/or it may reflect the fact that langurs are looked on favourably in most parts of India due to their supposed connection with the monkey god Hanuman (indeed, the name Semnopithecus means "sacred monkey") and are tolerated by humans or even actively encouraged and fed. Langur social structure varies significantly between different areas, possibly also as a result of food availability and population density. Like lions in Africa, langur troops are based on related females, with male offspring being evicted as they reach maturity, often forming nomadic all-male clusters. In some areas, breeding troops may include a number of mature males co-existing relatively peacefully, but in many areas most troops generally include only a single mature male. Also like lions, eviction of the incumbent male by another male in single-male areas is also often followed by the entering male killing any young already present in the troop in order to favour the raising of his own young. Interestingly, females who are pregnant at the time of takeover will engage in "pseudo-oestrus" behaviour - to completely anthropomorphise things, they fake sexual interest in order to induce the invading male to accept their offspring as his own. Production of young in all colobines often involves their being "shared around" between members of a troop, and females will often "borrow" and nurse the young of other females.

REFERENCES

Brandon-Jones, D. 1984. Colobus and leaf monkeys. In All the World’s Animals: Primates (D. Macdonald, ed.) pp. 102-113. Torstar Books: New York.

Groves, C. P. 2001. Primate Taxonomy. Smithsonian Institution Press: Washington.

Osterholz, M., L. Walter & C. Roos. 2008. Phylogenetic position of the langur genera Semnopithecus and Trachypithecus among Asian colobines, and genus affiliations of their species groups. BMC Evolutionary Biology 8: 58.