New bird species discovered

A new bird species has been discovered in Indonesia. Grrlscientist has the details:

A formal description of this new species, the Togian white-eye, Zosterops somadikartai, was just published in the March issue of the ornithological journal, The Wilson Journal of Ornithology. Not only was this bird recognized as a new species, but its population and home range were so small that this species was recommended to be added to international endangered species lists.

Linneaus’ Legacy #4

I missed this, but Linneaus’ Legacy #4 has been up at The Other 95% since last week.

Guardian of the grasses

Anoop Sindhu and colleagues report on a gene that may have played a key role in the evolution of grasses. The gene, Hm1, provides resistance against Cochliobolus carbonum race 1 (CCR1), a fungus that is capable of attacking and killing corn at any stage of its development (images of CCR1 infection). While CCR1 is only known to affect corn, the gene Hm1 and its relatives are present throughout the grass family, but are absent from other lineages.

CCR1 is only known as a disease in Zea mays, but the Hm1 family of genes throughout the grass family. Sindhu and colleagues silenced the corresponding gene in barley. This resulted in barley that was susceptible to CCR1. The fungus is able to invade susceptible grasses through the production of Helminthosporium carbonum* (HC) toxin. The ability of Hm1 and related genes to resist CCR1 comes from an enzyme known as HC-toxin reductase (HCTR), which detoxifies HCTR.

A phylogenetic analysis of the Hm1-gene family showed that they were monophyletic – they all shared a common ancestor. Since it is present throughout the grass family, but is absent from all other groups of plants, it appears that the gene shares its origin with the grass family. This lead the authors to conclude that:

The maintenance of HCTR gene function in maize and barley, coupled with the unique phylogenetic position of the Hm1 gene (with no closely related orthologs in eudicots), suggests that Hm1 may have played a critical role in the evolution of most of our cereal crops. Given the devastating potential of CCR1 to kill susceptible corn, it is likely that this fungus or its ancestral form would have threatened the existence of grasses, or at least severely constrained their geographical distribution, had Hm1 not evolved to detoxify HC toxin. Thus, it seems likely that Hm1 served as a guardian of the grass family, allowing it to survive, thrive, and evolve into crops that feed the world.

*Helminthosporium carbonum is the asexual form of Cochliobolus carbonum. Since fungi are classified on the basis of their sexual structure, fungi whose fruiting bodies are unknown often end up being described as distinct species.

Sindhu, A., Chintamanani, S., Brandt, A.S., Zanis, M., Scofield, S.R., Johal, G.S. (2008). A guardian of grasses: Specific origin and conservation of a unique disease-resistance gene in the grass lineage. Proceeding of the National Academy of Sciences USA, 105(5), 1762-1767. DOI: 10.1073/pnas.0711406105 Open Access

The end of Drosophila as a model organism?

Looks like the days of Drosophila melanogaster as a model organism are numbered. It’s likely to be displaced by Sophophora melanogaster. Want to know why? Check out Catalogue of Organisms.

(Looks like the genus Drosophila is paraphyletic, which means that it has to be split…and D. melanogaster ends up on the wrong side of the tracks, so to speak).

H/T Sandwalk.

A remarkable new palm from Madagascar

As a result of its long isolation, Madagascar has unique biota. Although it is best known for its lemurs, Madagascar’s palm flora is both diverse and distinctive. In 1995 Dransfield and Beentje recognised 170 species of palms from Madagascar, 164 of which were found only in Madagascar. Since then another 7 species have been described, with another 20 apparently awaiting description. Most of these new species have been found in the eastern wet areas. The western part of the island is drier, and has a much less diverse palm flora. However, an entirely new genus has been discovered in the western dry region – one that is so large and distinctive that the BBC reports it can be seen in satellite images. A description of this new species, Tahina spectabilis was published in the January issue of the Botanical Journal of the Linnean Society.

Tahina, which means “blessed” or “to be protected” in Malagasy (and is also the name of the daughter of the Metz family, Anne-Tahina), is a remarkable tree. It is one of the largest palms in Madagascar, growing 10 m tall (20 m according to the BBC article) with stem diameter of 50 cm. It is also hapaxanthic – it reproduces just once in its lifetime and then dies. As a result of this, it puts all of its resources into flowering, producing a 4-m tall inflorescence. (You can see an image of it here.)

In August 2005 the Metz family first observed the species on a family picnic, but since it was not flowering, they assumed that it was a Borassus. However, when they returned in 2006 they saw the tree in flower. Their pictures were posted on the PalmTalk bulletin board by Bruno Leroy on December 5, 2006, where its similarity to the Asian genus Corypha was noted. One of the regulars on the board contacted John Dransfield of Kew Gardens, who determined that the species was not a Borassus, and thought that it was unlikely to be a Corypha, since the area appeared to be too remote for one to have been planted there. Images of the crown were also inconsistent with Corypha. Corypha (the Talipot Palm) has a similarly massive terminal inflorescences (picture, on right) and has been planted around the world. I have seen them in flower in Trinidad and Puerto Rico, and one of them in flower is a truly remarkable sight.

In January 2007 Mijoro Rakotoarinivo, Bruno Leroy and the Metz family visited the site and made the first botanical collections of the species. The species was determined to be an unknown member of the tribe Chuniophoeniceae which comprised of three genera: Nannorrhops, which is found from Arabia to Afghanistan, and Pakistan; Kerriodoxa which is found in southern Thailand; and Chuniophoenix which is found in Vietnam and southern China. Unlike Tahina, these genera are slender or moderate sized palms. In addition to being physically distinctive, Tahina is also geographically disjunct from its closest relatives.

Apart from everything else about this tree, I especially like the internet aspect. Certain taxa, like palms and fish, support dedicated communities of enthusiasts. Their interest can not only lead to new discoveries, it can also be harnessed into research and conservation efforts. And, remarkably, they generate groups of non-scientists who actively read taxonomic monographs. And to me, that’s just awfully cool.

Dransfield, J., Rakotoarinivo, M., Baker, W.J., Bayton, R.P., Fisher, J.B., Horn, J.W., Leroy, B., Metz, X. (2008). A new Coryphoid palm genus from Madagascar . Botanical Journal of the Linnean Society, 156(1), 79-91. DOI: 10.1111/j.1095-8339.2007.00742.x

Dransfield J, Beentje HJ. 1995. The Palms of Madagascar. Royal Botanic Gardens Kew and International Palm Society, HMSO Norwich.

Names for new species

Afarensis talks about the sale of naming rights for a new owl butterfly species. Opsiphanes blythekitzmillerae was named for Margery Minerva Blythe Kitzmiller. The right to name the species was auctioned for $40,800. The money went to support Mexican butterfly research.

Once upon a time, taxonomists named species in honour of their patrons. Even today, a beer can sometimes earn you a species named in your honour. In this context, selling the rights to a species name isn’t all that unusual, and I can’t complain too much if the money goes for research. But we shouldn’t be returning to the days in which scientists were dependent on wealthy patrons. While Afarensis saw it as a dangerous precedent (looking forward with distaste to the idea of Australopithecus microsoftecus), I see it more as a return to an outdated model. Species names should be descriptive, they should convey some information about the species. The specific epithet blythekitzmillerae tells me nothing about the species.

The issue of selling naming rights should never come up. Sure, they could sell the rights to their made up common name – let someone pay $40,000 to name Blythe Kitzmiller’s owl butterfly. Far too many people see scientific names as nothing but a string of latinised words that are there to confuse them. Using trivial or meaningless names only heightens that perception. It doesn’t mean the names have to be prosaic – I love clever puns. But please, keep the names meaningful.

Dispersal, vicariance and press releases

Ceiba pentandra (the silkcotton, kapok or ceiba tree) has a broad distribution including across the Neotropics and Africa. A cultivated form is grown across a wider range for kapok fibres. The trans-Atlantic distribution of C. pentandra has attracted attention for a long time – based on the fact that there are nine species in the Neotropics and only one in Africa, it has generally been assumed that it is a Neotropical species that dispersed to Africa. How it got there has long been a question.

EurekaAlert! published a press release attributed to the National Science Foundation about a paper published in Molecular Ecology concerning the trans-Altantic distribution of Ceiba pentandra, the silk cotton or kapok tree. The paper* considers three mechanisms by which the species could have come to be present on both sides of the Atlantic: Gondwana vicariance, Boreotropical dispersal (and subsequent vicariance) and long-distance dispersal.

In the case on Gondwana vicariance, the distribution would reflect the fact that South America and Africa were connected (as parts of Gondwana) until 96 million years ago.  In the case of Boreotropical dispersal, the species would have colonised Africa about 35 million years ago through a then warmer North America and Europe, only to be lost from those areas as the climate warmed.  Both of these would be expected to produce deep divergence between African and South American C. pentandra populations.  On the other hand, if long-distance dispersal across the Atlantic took place more recently, the divergence would be smaller.

The paper found evidence for recent dispersal.  The authors noted that:

Ceiba pentandra has the weakest phylogeographical structure yet reported for a widespread rainforest tree species. Apart from the cluster of sites in Western Ecuador having a variant psbB-psbF haplotype, there was no cpDNA variation across Mesoamerica, the Amazon basin, and West Africa. In fact, this study found less cpDNA variation across three continents than some rainforest tree species exhibit within putative breeding populations in French Guiana and Brazil (Hamilton 1999b; Dutech et al. 2000; Latouche-Halle et al. 2003) or among sample sites at regional scales in French Guiana and across Mesoamerica (Caron et al. 2000; Cavers et al. 2003).

In this regard, C. pentandra is by no means unique – several other species have been found that have recently crossed the Atlantic, including Symphonia globulifera, which apparently colonised the Americas from Africa.

One thing that bothers me is the press release.  It opens with

Celebrated in Buddhist temples and cultivated for its wood and cottony fibers, the kapok tree now is upsetting an idea that biologists have clung to for decades: the notion that African and South American rainforests are similar because the continents were connected 96 million years ago.

It’s obvious that whoever wrote the press release didn’t spend much time looking at the paper.  While the issue of Gondwanan roots is considered, it’s by no means a new idea.  At the same time, it’s a fairly limited suite of trees that are shared between the two areas, and evidence of recent trans-Atlantic dispersal by a few species does not “[upset] an idea that biologists have clung to for decades”.  That’s nonsense.

* Christopher W. Dick, Eldredge Bermingham, Maristerra R. Lemes and Rogerio Gribel. Extreme long-distance dispersal of the lowland tropical rainforest tree Ceiba pentandra L. (Malvaceae) in Africa and the Neotropics. Molecular Ecology (OnlineEarly Articles). doi:10.1111/j.1365-294X.2007.03341.x

H/T Agricultural Biodiversity Weblog.