Taxon of the Week: Nothing to do with Teapots

This piece of rudeness was more than Alice could bear: she got up in great disgust, and walked off; the Dormouse fell asleep instantly, and neither of the others took the least notice of her going, though she looked back once or twice, half hoping that they would call after her: the last time she saw them, they were trying to put the Dormouse into the teapot.
--Lewis Carroll, Alice's Adventures in Wonderland

The dormouse was an animal that I had heard of long before I knew what one actually was, solely as a result of its appearance in Alice's Adventures in Wonderland, a book I read countless times as a young'un (the image at the top, a reproduction of one of John Tenniel's original illustrations for Alice, comes from here). Those of you who have read the book will recall that the main characteristic of the Dormouse was its continually falling asleep - doubtless because, Alice's Adventures being set in July, it was time the dormouse should have been hibernating.



Okay, the picture's obviously posed (if not photoshopped) using a hibernating dormouse, but sometimes cuteness is irresistable and I thought it might draw a larger audience among Japanese schoolgirls (image from the Cellar). Dormice (Gliridae*) are a smallish family of mostly Palaearctic rodents. The name is supposed to come from the same source as the word "dormant" and refers to the hibernation by species in colder climates. Dormice do resemble rather solidly built mice, but features of the internal anatomy, supported by molecular data, indicate that Gliridae are not, in fact, close relatives of the Muroidea (mice and rats proper) but are more closely related to the Sciuroidea (squirrels), their mouse-like features having arisen convergently (Maier et al., 2002). The relatively long fossil record of Gliridae, dating back to the Eocene, also supports a more basal position for the family.

*Some references will use the name Myoxidae for the same family. There may also be a single family Gliridae, or a superfamily Gliroidea containing two families, depending on whether the specialised Selevinia (see below) is regarded as belonging to a separate family or as a derived member of the Gliridae.



Dormice are seemingly fairly omnivorous. Animal Diversity Web describes their diet as "feeding on fruit and nuts and also eating invertebrates, birds and their eggs, and sometimes other rodents". One rather unique species, the rare Selevinia betpakdalensis of Lake Balkhash in Kazakhstan (shown in an illustration from Animal Diversity Web above), has a highly reduced dentition (see image below from here) and is mostly insectivorous.



The tendency of hibernating species to stack on the fat in preparation for winter gives rise to the common name of the European species Glis glis - the edible dormouse. This species was eaten in Imperial Rome, though the image below (from The Daily Mail) suggests that it may have been a little difficult to get the apple into its mouth. The Old Foodie has a recipe for stuffed dormouse taken from a translation of Apicius*, while Roman History Books and More also gives a quote from Petronius referring to dormice coated with poppy seeds and honey. Tasty!



*I'm a little confused about the "laser" that is supposed included in the stuffing. Is this a misprint for "laver" (an edible seaweed), or is there actually a vegetable by that name?

REFERENCES

Maier, W., P. Klingler & I. Ruf. 2002. Ontogeny of the medial masseter muscle, pseudo-myomorphy, and the systematic position of the Gliridae (Rodentia, Mammalia). Journal of Mammalian Evolution 9 (4): 253-269.

Circus of the Spineless #29

Circus of the Spineless #29 is up at Andrea's Buzzing About. This months edition features snails and Superman, ants and apple moths, dragons and damsels, and much, much more. Enjoy!

What Would the ICZN Do?

The science-blogging world has seen a fair bit of discussion in the last couple of days over an alleged piece of unethical behaviour on the part of certain researchers at the New Mexico Museum of Natural History and Science, who have been accused of rushing articles into print deliberately pre-empting or even plagiarising the work of other researchers. I won't repeat all the sordid details here - instead, I recommend that you go to Tetrapod Zoology and read what Darren Naish has to say. However, a question has emerged in the comment thread at Darren's post that I feel is worth addressing.

Among the matters directly affected by this underhanded dealing is the correct name for what once was Desmatosuchus chamensis. Two separate papers were published in rapid succession (only two weeks apart) placing this species in a new genus, which the earlier-published paper dubbed Rioarribasuchus and the latter-published dubbed Heliocanthus. The principle of priority demands that the earlier-published name is the correct one, making the creature Rioarribasuchus. The problem is that the very brief earlier paper has been accused of being based on the PhD thesis of the author of the much more detailed later paper, which provided the basis for the later paper. If this is the case, it would be a serious ethical breach, and it would seem unfair to continue to use the unethically published name.

The International Code of Zoological Nomenclature is not completely silent on the question of ethics - a Code of Ethics appears in an appendix to the Code which states (among other things) that, "A zoologist should not publish a new name if he or she has reason to believe that another person has already recognized the same taxon and intends to establish a name for it (or that the taxon is to be named in a posthumous work). A zoologist in such a position should communicate with the other person (or their representatives) and only feel free to establish a new name if that person has failed to do so in a reasonable period (not less than a year)." However, this is included as a recommendation, rather than a rule. Indeed, the Code then goes on to state that, "The observation of these principles is a matter for the proper feelings and conscience of individual zoologists, and the Commission is not empowered to investigate or rule upon alleged breaches of them."* In other words, even if unethically published, Rioarribasuchus is still the correct name. Some of the commentors at Tetrapod Zoology have pointed out that people are entirely at liberty to ignore Rioarribasuchus and use Heliocanthus anyway, and to a certain extent they are quite right. After all, the ICZN is only accepted as correct by the compliance of the researchers using it - no legal penalties will attend a researcher who does not follow the letter of the ICZN. However, the problem with this approach is that the name Rioarribasuchus is still out there, and might always be re-introduced as the correct name by future researchers who are unaware of the controversy surrounding it. In such a case, the confusion potentially caused by having two "correct" names floating about for the same organism possibly outweighs the ethical advantages.

*Okay, so that might contradict my comment at the Tetrapod Zoology thread on the ability of the ICZN to declare the unethical name invalid. My mistake.

This may seem like a rather senseless state of affairs, but in fact there are good reasons why the ICZN has not made the ethical code obligatory. Deliberate ethical breaches are extremely difficult to demonstrate, and things might be overly complicated if names could be quashed for ethical reasons. To illustrate my point, I'll give you two examples of names that have been accused of ethical beaches that are less clear than the Rioarribasuchus case.

The name Archaeoraptor was attached to a fossil specimen illustrated in a 1999 issue of National Geographic. At the time of the Geographic article, a formal description of the specimen and the name was supposed to be published in Nature (the National Geographic article did not include a description of the specimen, and so does not count as valid publication for the purposes of nomenclature). However, before the formal description was published, it was discovered that the "Archaeoraptor" fossil was actually a chimera, composed of fossils of two different animals that had been joined into one (who exactly was responsible for the fusion, and whether it was originally done knowingly or inadvertently, remain open questions that will probably never be answered). The anterior part of the fossil was a basal bird, while the posterior part belonged to a small dromaeosaur that would later be described from more complete remains as Microraptor. The formal description was never published. However, Storrs Olson, a prominent palaeornithologist at the National Museum of Natural History who had made a public complaint about National Geographic's publication of the invalid name, published an editorial in the museum newsletter in which he briefly described the fossil and suggested that the name Archaeoraptor be restricted to the dromaeosaur remains (probably to directly prevent the name from becominng attached to ornithology). Unfortunately, Olson's publication actually pre-dates the publication of the name Microraptor, raising the possibility that Archaeoraptor is the correct name for this now well-known dinosaur. In this case, the general decision seems to have been to let sleeping dogs lie - there is a good case to be made that Olson's editorial also does not constitute a valid publication, and most researchers feel that it can be safely disregarded.

The other case involves another dinosaur name scandal. The dinosaur genus Syntarsus was named by Raath in 1969, but the name was later realised by a team of entomologists (Ivie et al.) to have been used for a beetle genus in 1869. Normally, it is considered good form to allow the original author the chance to replace the invalid name him/herself, and so not lose the connection to the organism he/she discovered (the ICZN Code of Ethics says that, "A zoologist should not publish a new replacement name (a nomen novum) or other substitute name for a junior homonym when the author of the latter is alive; that author should be informed of the homonymy and be allowed a reasonable time (at least a year) in which to establish a substitute name.") Ivie et al. claim to have attempted to contact Raath, but on receiving no reply assumed (incorrectly) that he had passed away, and in a 2001 issue of the entomological journal Insecta Mundi they somewhat facetiously published the replacement name Megapnosaurus (which translates as "big dead lizard"). The inappropriate derivation, the pre-emption of Raath and the publication in a source of whose very existence most vertebrate palaeontologists would be unaware meant that the name caused a great deal of protest - it was grudgingly admitted that the name was valid, but many continued to insist on the invalid "Syntarsus" in protest. In this case, the issue has only been resolved by the fact that most researchers no longer regard Megapnosaurus as a separate genus from the closely related Coelophysis, though it must be admitted that the desire to lose Megapnosaurus was certainly a factor in many people's willingness to accept the synonymy.

The main point of these examples is that in both it is pretty much impossible to say whether the offending authors can be said to have acted ethically or not - and indeed, whether or not their actions would be regarded as unethical depends rather strongly on the interests of the person doing the regarding. It is to avoid setting precedents that would lead to complex and potentially unresolvable debate on such grey areas that the ICZN makes the ethical code effectively voluntary. On the other hand, while their names may remain, it seems likely that a researcher who engaged in repeated unethical conduct would eventually find their career suffering as their peers realised what was going on!

REFERENCES

The Wikipedia page on Archaeoraptor has a good overview of the controversy surrounding this name. The name Megapnosaurus was published in:

Ivie, M. A., S. A. Slipinski & P. Wegrzynowicz. 2001. Generic homonyms in the Colydiinae (Coleoptera: Zopheridae). Insecta Mundi 15: 63-64.

Some History of the History of Tetrapods

Titanophoneus potens, a Permian synapsid (image from Kheper).

Benton, M. J. (ed.) 1988. The Phylogeny and Classification of the Tetrapods. The Systematics Association Special Volume 35A & 35B. Clarendon Press: Oxford.

One interesting thing about comparing different fields of research is the different time-scales we work in when it comes to what constitutes a "recent" publication. As an invertebrate taxonomist, I think nothing of delving into stuff that was written in the 1950s or even earlier. A developmental geneticist is likely to regard anything more than a few years old as ancient history. Vertebrate palaeontology lies between these two extremes, but certainly 1988 was a long time ago for the tetrapods.

As a result, I suspect that Phylogeny and Classification of the Tetrapods can't really tell us much about the current state of tetrapod classification. What does make it interesting, though, is what it says about the state of vertebrate palaeontology at the time. The late 1980s were certainly interesting times, not just in vertebrate palaeontology but in systematics in general. The cladistic revolution was gathering speed. Molecular phylogeny was making its first faltering steps, and challenging a few orthodoxies.

The Phylogeny and Classification of the Tetrapods was published in two volumes, and even that says something about changes in focus since. The second volume was devoted entirely to the mammals (about 5,400 living species). Everything else - amphibians, reptiles, birds, about 24,000 living species - took up only the first volume. Birds in particular warrant a single chapter, as do living amphibians (that latter point possibly hasn't changed much). Dinosaurs (the non-birdy type, that is) barely rate a mention. The dinosaur renaissance was in its early stages at the time - for comparison, Bakker's The Dinosaur Heresies, a book I personally don't think much of but which became something of a focal point for changing views on the big lizards, was first published in 1986. (It was also in 1988 that Gregory S. Paul's Predatory Dinosaurs of the World first hit the shelves, in which Paul copped a certain degree of ridicule for his decidedly heterodox reconstructions of dinosaurs covered in feathers - Paul has since, of course, been able to carry around a big bag of harsh words and force his critics on this point to eat them.) Of course, it should be noted that despite its palaeontological bent, ultimately the main focus of Phylogeny and Classification of the Tetrapods is on the relationships between living tetrapods.

Despite all that has changed since then, some parts of Phylogeny and Classification of the Tetrapods seem somewhat prescient. Not so much the molecular chapters - that on molecular phylogenetics of tetrapods as a whole has the grim figure of the Haematothermia clade (birds and mammals to the exclusion of reptiles) rear its ugly head, though the authors at least had the sense to recognise this as probably convergence rather than the actual state of affairs. But the mammalian molecular phylogeny chapter gives us some of the early glimmerings of the Afrotheria hypothesis, though that clade was not to be formally recognised until some years later, while the Novacek et al. chapter on the morphological phylogeny of modern mammalian orders is noteworthy for not finding any support for Ungulata.

The prize for best statement in the book, however, has to go to Gaffney & Meylan's chapter on turtles, where, after a description of the apomorphies connecting turtles to their supposed nearest relatives (the captorhinids, in this case), the authors note "And so we reach God's noblest creature - the turtle".

The One about Sexual Cannibalism

Sometimes, the history of people's misconceptions about organisms are nearly as interesting as the organisms themselves - not so much because of what it says about the organism itself, but what it says about us as people. One common pattern is the "pendulum swing" in conceptions about certain organisms. An originally negative over-simplification about a given organism ("wolves are savage human-killers that should be exterminated before they exterminate us"/"whales and dolphins are just fish and can be hunted as such") is replaced by a reactionary viewpoint which is more positive, but arguably just as erroneous an oversimplification ("wolves are completely harmless to humans, and would never attack somebody"/"whales and dolphins are super-intelligent, and, like, just filled with spiritual wisdom"). It is only as our attitudes mature, and the question becomes less politically charged, that opinions settle towards the generally more accurate but usually more complex middle ground.

Sexual cannibalism is one behaviour that has fallen victim to the human tendency to mythologise. Many people are aware of the idea that female spiders, mantids and other such carnivorous arthropods have a habit of eating the male during mating. Any feminist readers I have out there might be interested to consider how the popularity of this concept reflects our own attitudes on the relationship between the sexes (the female eating the male seems scandalous because, of course, we live in a society that tells us it should be the other way around). However, if you open a textbook you will probably be told that this story is generally not true. Bug Girl has recently corrected Isabella Rossellini on just this point*. For the most part, Bug Girl is right - sexual cannibalism is a fairly rare occurrence that usually only happens when things go wrong (for instance, if the male makes his move before properly placating the female). However, there is at least one species in which sexual cannibalism is an integral part of the mating process.

*Actually, speaking of societal attitudes, perhaps the most remarkable thing about the video Bug Girl has posted - other, of course, than the fact that Isabella Rossellini is making videos about arthropods in the first place - is the obvious cultural differences when it comes to talking about sex. The American interviewer with her giggling prudishness does not compare well to Rossellini's far more relaxed attitude.

That species is Latrodectus hasselti, the redback spider. The image at the top of the page (from here) shows two redbacks. The larger individual is a mature female, while the smaller white individual is a male. The genus Latrodectus has a wide distribution around the world, including the black widow (L. mactans) of North America (which does not regularly engage in sexual cannibalism), with most species having a well-deserved reputation for toxicity. The redback had done particularly well out of human civilisation - it is unclear where exactly in Australia it originated*, but it has since been spread throughout the continent, as well as establishing populations in other countries such as New Zealand and Japan. Latrodectus hasselti specialises in constructing its webs between hot, dry, facing surfaces, and humans are very good at building hot, dry, facing surfaces.

*Some people have suggested that the redback is not a native to Australia because of the absence of early records of this species, and its close association in most areas with humans. Conflicting with this is the absence of redbacks in any other part of the world, apart from areas where it has obviously been imported in Australia. It is far more likely that the redback had a much more restricted distribution in Australia prior to European settlement (probably somewhere west of the Great Dividing Range) and has since been spread to the remainder of the country.



In other Latrodectus species, the small male first climbs onto the female's web and approaches her cautiously with regular stops to vibrate the web. The female will usually chase him away a few times, but eventually she calms down and the male is able to climb onto the underside of the female as she hangs upside-down on the web, as shown above in Latrodectus hesperus (image from here). The female remains largely immobile while the male mates with her, and he is able to make his escape quite easily. In the redback, the male approaches and mounts the female as in other Latrodectus but once he has inserted his pedipalp into her he performs a back-flip that brings his abdomen alongside her mouthparts. The female, seemingly unable to resist the temptation, bites into the male and begins chewing. After a while, the male pulls away from the female and rips his badly damaged abdomen out of her grasp. Nevertheless, after a period of grooming the male returns to the female, and inserts and repositions himself as before. This time, the female does not allow him to escape - the male does not survive the second mating.

Why does the male submit himself to this fatal attack? There are a few possibilities that have been suggested. The nutrients the female receives from eating the male may aid in the development of the eggs he has fertilised. Also, the female remains mating with the male for longer while feeding on him than she would have otherwise. Not only does this allow the male more time to fertilise her eggs, it also denies other males the chance to mate with her in this time. A thesis abstract available here indicates that some males try to escape the role of victim, attempting to sneak in and mate with the female without offering themselves. However, females react even more aggressively to such cheaters, who were much more likely to be cannibalised before mating was successfully completed.

REFERENCES

Forster, R., & L. Forster. 1999. Spiders of New Zealand and their Worldwide Kin. University of Otago Press: Dunedin, in association with Otago Museum.

Linnaeus' Legacy time

The next round of Linnaeus' Legacy is fast approaching, and will be held by Kevin over at The Other 95%. Get your taxonomy-related writings in to me or Kevin by the 8th of February!

Drosophila forever?

As I've commented before on this blog, taxonomy holds an unusual position in the biological sciences in that it fills two equally significant roles. On the one hand, it is a science in its own right, investigating the best way to describe and express the relationships between organisms. On the other hand, it supplies the means for communication between biologists in all fields. For the most part, these two aims compliment each other, but sometimes they can clash. The first aim implies continual change, as our understanding of the relationships between organisms changes and (hopefully) improves. Wheeler (2007) commented in a recent editorial that "Doing taxonomy as an independent science advances simultaneously both the aims
of taxonomy and its users", a sentiment that I agree with fully (be warned, though, that the general tone of Wheeler's editorial is fairly incendiary). To fulfil the second aim, however, a certain amount of stability is usually desired, as researchers who are not working in taxonomy may have trouble keeping up with the changes (or, for that matter, appreciating their necessity).

All of the codes of nomenclature have a central commission to regulate taxonomy - zoology has the International Commission on Zoological Nomenclature, botany has the International Association for Plant Taxonomy. One of the main roles of these commissions is to allow suspension of the usual rules in cases where their strict application would cause more trouble for communication than otherwise. In the case of zoology, applications for rulings on such cases that are submitted to the ICZN are published in the journal Bulletin on Zoological Nomenclature, allowing researchers the opportunity to comment on submissions before the Commission decides on them. One submission that appeared in the December 2007 issue of the BZN involves a case that could affect a large number of researchers in many fields - the impending revision of the fly genus Drosophila.

Drosophila is a very large genus, containing about 1500 species. However, phylogenetic studies (e. g. Robe et al., 2005) have found that Drosophila as currently defined is significantly paraphyletic with regard to a number of other genera in the family Drosophilidae. There are two options to resolve this situation. One is to sink all the smaller genera arising from Drosophila into the larger genus. However, this is not regarded as a suitable solution - not only would it leave Drosophila with over 2000 species, but it would result in over a hundred secondary homonyms (two or more species ending up with the same name as a result of change in genus assignment) that would require correction. The other option, that seems much more likely to be used, is to divide Drosophila into a number of smaller genera. The name Drosophila would then be restricted to a smaller group of species closely related to the type species.

All this would be fairly routine, except that one of the species affected happens to be one of the most widely used model organisms in genetics - the "fruit fly" Drosophila melanogaster (the inverted commas are because Drosophila isn't really a fruit fly proper, but a vinegar fly). So familiar is this species that many people simply refer to it as Drosophila without invoking the species name. One might be forgiven for expecting D. melanogaster to be the type species of Drosophila, but it's not. That honour goes to Drosophila funebris (shown at the top of the post in a photo from here). And as it happens, the two species are not that closely related. If Drosophila is divided up, the Drosophila melanogaster everyone knows and loves becomes a far less familiar Sophophora melanogaster. How will geneticists respond to the loss of their favourite organism?

To avert an apocalypse in evolutionary biology, van der Linde et al. (2007) have made a submission to the ICZN to redefine the type species of Drosophila. They suggest that that honour be given to D. melanogaster rather than D. funebris, meaning that D. melanogaster would remain forever more Drosophila. But if this is accepted, what will become of D. funebris and its close friends and relatives? Will the ICZN exalt D. melanogaster to the position of type species? Or will the geneticists just have to learn to refer to Sophophora, and like it?

REFERENCES

Linde, K. van der, G. Bächli, M. J. Toda, W.-X. Zhang, Y.-G. Hu & G. S. Spicer. 2007. Case 3407: Drosophila Fallén, 1832 (Insecta, Diptera): proposed conservation of usage. Bulletin of Zoological Nomenclature 64 (4).

Robe, L. J., V. L. S. Valente, M. Budnik & E. L. S. Loreto. 2005. Molecular phylogeny of the subgenus Drosophila (Diptera, Drosophilidae) with an emphasis on Neotropical species and groups: a nuclear versus mitochondrial gene approach. Molecular Phylogenetics and Evolution 36: 623-640.

Wheeler, Q. D. 2007. Invertebrate systematics or spineless taxonomy? Zootaxa 1668: 11-18.