Field of Science

Melastomes and Pals

Princess flower Tibouchina heteromalla, copyright João Medeiros.

For most botanists currently working on flowering plants, the default taxonomic framework for their studies is the classification published by the Angiosperm Phylogeny Group. This is not the only classification for angiosperms proposed in recent years, but it is the most widely recognised, and it is the one that all its competitors are compared to. If there is one major deficiency of the Angiosperm Phylogeny Group classification, it is that it eschews the use of formal categories between 'orders' (which it tends to define broadly) and 'families'. As such, there are a number of well-supported clades that require one to turn to alternative classifications for suitable names.

Crypteronia paniculata, copyright Tony Rodd.

The Melastomatineae, as recognised by Reveal (2012), for instance, is a clade of mostly tropical and subtropical plants within the Myrtales commonly recovered by molecular phylogenetic analyses. Most of its members are included in the pantropical family Melastomataceae, but it also includes three much smaller and more localised families: the southeast Asian Crypteroniaceae, the western Neotropical Alzatea and the African Penaeaceae. Some authors also divide the Melastomataceae into two families Melastomataceae and Memecylaceae, but as the two groups are universally accepted as sister clades this is purely a matter of taste. Morphological characters uniting the families are few (see the Angiosperm Phylogeny Website). Many accumulate aluminium in the leaves, to the extent that the leaves of the small tree Memecylon edule were used in India as a mordant for fixing dyes to cloth. The flowers lack nectaries, and when nectar is produced in the Melastomataceae it exudes from locations such as the anthers or the corolla. Some Olisbeoideae (the Memecylaceae of other classifications) produce oil from glands on the anthers that is collected by pollinators in lieu of nectar. In the South American genus Axinaea, the anthers have a sugary appendage that is eaten by tanagers; as they attack it, a puff of pollen dusts their head. The anthers of Melastomataceae are often distinctly coloured from the rest of the flower, and arranged in a distinctive seried row on one side of the flower. The Melastomatoideae (i.e. Melastomataceae sensu stricto) also have distinctive leaves, with three or more strong longitudinal veins arising from the leaf base and connected by cross-veins.

Mountain hard pear Olinia emarginata, copyright H. Robertson. Olinia leaves smell of almonds when crushed, due to the presence of a cyanogenic compound.

Though Melastomataceae are often significant members of the tropical forest understorey, they tend not to have much direct economic significance for humans. Some, such as the princess flowers or glory trees of the genus Tibouchina, are grown as ornamentals. The hard pear Olinia ventosa of the Penaeaceae (no, I don't know why it's called that) is grown as a shade tree in South Africa. A few species of Melastomataceae are significant invasive weeds in warmer regions, including such luminaries as the Straits rhododendron Melastoma malabathricum and the evocatively-named Koster's curse Clidemia hirta. The velvet tree Miconia calvescens has earned itself the label of the 'purple plague' in Hawaii, where it over-runs native forest.


Reveal, J. L. 2012. An outline of a classification scheme for extant flowering plants. Phytoneuron 37: 1–221.

Orioles: The Genuine Article

Eurasian golden oriole Oriolus oriolus, copyright Crusier.

It is widely appreciated that the British during the age of exploration were probably not the most imaginative of baptisers. Thanks to their tendency to label the fauna of foreign lands with the names of familiar animals back home, we are regularly confronted with warblers that aren't warblers, cod that aren't cod, monkeys that aren't monkeys. And for years, many an American has laboured under the mistaken impression that they know what an oriole is. This post is about the real orioles.

The Oriolidae are a family of birds found mostly in the tropics of the Old World, from Africa to Australia. Only a few species in the family are known from temperate climes. One of these is the original oriole, the European Oriolus oriolus, which migrates between sub-Saharan Africa and its breeding range in Europe and central Asia. The name 'oriole' is derived from the Latin word for 'golden', and there is no question of this being an appropriate name for the European bird. The male's plumage is almost entirely golden yellow, with the wings being black. As is commonly the way with birds, the females are less dramatic, being predominantly green. Despite the males' bright coloration, though, orioles are by all accounts fairly retiring birds, usually remaining secluded in the tree canopy, where they seek out fruit and small insects.

Black-and-crimson oriole Oriolus cruentus malayanus, copyright Christopher Hill.

The majority of the about thirty remaining species of Oriolus are also some combination of gold, green and/or black, but there are notable exceptions. A clade of Australo-Papuan and Moluccan species, identified by Jønsson et al. (2010) as the sister group to the other Oriolus species, contains relatively dull brown or greenish species. The Moluccan species in this clade bear a strong resemblance to friarbirds, a group of honeyeaters found in the same region, to the extent that the black-eared oriole Oriolus bouroensis was first described as a friarbird. It has been suggested that this represents a case of mimicry with the retiring orioles gaining a degree of protection from their resemblance to the aggressive friarbirds (Dickinson 2004). Another Asian clade identified by Jønsson et al. (2010) includes mostly red and black species. It also includes the silver oriole Oriolus mellianus in which the red coloration has been mostly lost, so that it is mostly silver-white with a black head and wings.

Male and female Australasian figbirds Sphecotheres vieilloti, copyright Jim Bendon.

Also included in the Oriolidae are the three species of figbird in the genus Sphecotheres, found in the Australo-Papuan region. The figbirds, as their name suggests, have a higher proportion of fruit in their diet than orioles. They are also more sociable, living in small flocks. Figbirds are distinguished from orioles by the presence of patches of bright red bare skin around their eyes; they are otherwise a dull greenish colour. Recent studies have also indicated oriolid affinities for Pitohui, a genus of two red and black birds, the hooded pitohui P. dichrous and variable pitohui P. kirhocephalus, found in New Guinea. Previous authors have included six species in Pitohui, but phylogenetic studies have revealed that the genus in the broad sense is widely polyphyletic, with the remaining species belonging to different bird families. The red and black markings of the 'pitohuis' are a case of aposematic coloration, advertising that its bearer is toxic. The pitohuis contain batrachotoxins in their skin and feathers, a similar substance to that found in the poison-arrow frogs of South America. Contrary to what you may read elsewhere, the pitohuis were not the first known case of toxicity in birds, though it was one of the most definite ones. It has been known since ancient times that migratory quail Coturnix coturnix are toxic at certain points on their migratory route: the biblical book of Numbers describes a case of mass poisoning suffered by the Israelites during the exodus. Other examples of birds that are at least seasonally toxic include the spur-winged goose Plectropterus gambensis and the bronzewing pigeons of the genus Phaps (a brief review of bird toxicity is provided by Bartram & Boland, 2001). As far as is known, all cases of toxicity in birds result from feeding on something containing the relevant toxic substance (probably beetles, in the case of pitohuis) which is then sequestered by the bird.

Mounted North Island piopio Turnagra tanagra, copyright Te Papa.

The Australo-Papuan distribution of these two genera, together with the basal position of the Australo-Papuan species in the genus Oriolus, suggests that the family originated in this area before crossing the Wallace Line to diversify in Eurasia and Africa (Jønsson et al. 2010). An Australo-Papuan origin for the orioles also correlates with the presence of a fossil oriolid, Longmornis robustirostrata, in the early Miocene Riversleigh deposit of Australia (Boles 1999). It also correlates with the recent identification as oriolids of the now extinct New Zealand piopios of the genus Turnagra (Zuccon & Ericson 2012). The piopios were two species (the South Island piopio Turnagra capensis and the North Island T. tanagra) of mostly brown songbirds, also commonly known as the New Zealand thrushes. Their song was described as being amongst the most beautiful of any New Zealand bird, both complex and with a propensity towards mimicking other birds. Though seemingly common at the time of European settlement, they declined rapidly and probably became extinct around the start of the 20th Century. The affinities of the piopios were long contentious, with leading suggestions including a relationship with the whistlers of the Pachycephalidae, or with the bowerbirds of the Ptilonorhynchidae. Zuccon & Ericson (2012) marshalled an array of molecular, morphological and behavioural evidence in favour of a relationship with the orioles, though this stands in contrast with an earlier molecular study that supported the bowerbird hypothesis (Zuccon & Ericson noted that the cytochrome b sequence reported in the earlier study did not correspond with the one they found themselves, and suggested that it may have been the result of contamination). The dull coloration of the piopios compared to other orioles was explained by Zuccon & Ericson as a loss of sexual dimorphism, but this may have been unnecessary: they seem to have overlooked the similarly dull coloration of a number of other basal oriolids. The fact that the piopios were described as more terrestrial than the other oriolids is also not unusual in the New Zealand context. After all, the New Zealand bird fauna is famed for its tendency towards terrestrialisation (it even included a terrestrial owlet-nightjar!) In an environment where the main threat came from above in the form of birds of prey, the ground must have seemed like a welcoming place to be.


Bartram, S., & W. Boland. 2001. Chemistry and ecology of toxic birds. ChemBioChem 2: 809–811.

Boles, W. E. 1999. A new songbird (Aves: Passeriformes: Oriolidae) from the Miocene of Riversleigh, northwestern Queensland, Australia. Alcheringa 23: 51-56.

Dickinson, E. C. 2004. Systematic notes on Asian birds. 42. A preliminary review of the Oriolidae. Zool. Verh. Leiden 350: 47-63.

Jønsson, K. A., R. C. K. Bowie, R. G. Moyle, M. Irestedt, L. Christidis, J. A. Norman & J. Fjeldsa. 2010. Phylogeny and biogeography of Oriolidae (Aves: Passeriformes). Ecography 33: 232–241.

Zuccon, D., & P. G. P. Ericson. 2012. Molecular and morphological evidences place the extinct New Zealand endemic Turnagra capensis in the Oriolidae. Molecular Phylogenetics and Evolution 62: 414–426.

Barrallier's Monkey

"Gogy told me that they had brought portions of a monkey (in the native language "colo"), but they had cut it in pieces, and the head, which I should have liked to secure, had disappeared. I could only get two feet through an exchange which Gogy made for two spears and one tomahawk. I sent these two feet to the Governor in a bottle of spirits."

In November 1802, Governor Philip King sent an exploratory expedition west of Sydney under the command of Ensign Francis Barrallier, a French ex-pat who had taken service with the British after fleeing France with his parents following the French revolution. As well as finding a passage across the mountains that barred Sydney from the interior, Barrallier was trying to find the seat of a figure that Governor King later referred to in letters as the 'King of the Mountains'. Who exactly this King of the Mountains was supposed to be is unclear. Many have thought he was supposed to be some sort of overlord of the local Aboriginals. David Levell, in his 2008 book Tour to Hell, argues the King of the Mountains to have been the head of a secret inland settlement that many of the convicts imprisoned in Sydney believed would offer sanctuary to any who escaped there. Barrallier returned to Sydney in late December, having failed to locate either passage or king (the one would be discovered later, the other would prove to be mythical under any interpretation). Barralier's journal of his expedition languished in relative obscurity until an English translation was published in 1897.

The main interest for later readers of Barrallier's account has been in his dealings with the indigenous people he encountered and worked with. Barrallier had an interest in developing a rapport with the local people he met that was not shared by most of his British associates and his notes, sparse as they may be, provide one of the few direct records available of pre-colonial life in the Sydney region. I've brought Barrallier into this post, however, because of an incident he describes briefly in his journal where the game procured by some of Barrallier's aboriginal associates included an animal that Barrallier refers to as a 'monkey'. Barrallier did not see the animal's remains before it had already been butchered, but he is still the first European known to have acquired a specimen of one of Australia's most iconic animals: the koala.

Koalas Phascolarctos cinereus, photographed by Dinkum.

Koalas are widespread in the east of Australia, though loss of habitat has rendered their distribution localised in some areas. To most people outside Australia, the koala seems like a plush toy come to life, the essence of cuteness manifest in a single animal. The Australians themselves often have a more ambivalent attitude: while the koala is certainly a high-ranking member of the pantheon of the Australian fauna, together with such luminaries as the kangaroo, the platypus, the kookaburra and the gumnut baby, Australians also tend to look upon it as indolent, bad-tempered, and steeped in the kind of aroma that only an exclusive diet of eucalyptus leaves can give an animal (many Australians look more affectionately on the koala's closest living cousin, the wombat). To zoologists, Phascolarctos cinereus is the only surviving species of a lineage that goes back at least to the late Oligocene. Three subspecies of koala have been recognised, but these probably represent clinal variations rather than geographically discrete units (Houlden et al. 1999).

At just what point koalas became eucalyptus specialists is something we don't know for sure. The late Oligocene Perikoala palankarinnica possesses an ankylosed lower jaw (i.e. one that has the two sides fused together at the front) that may indicate a diet of tough leaves (Long et al 2002). Eucalyptus would be at least one candidate for such a diet. However, Perikoala's rough contemporary, Madakoala, lacked such a fused jaw and may have taken softer browse. Nor is a fused lower jaw present in the Miocene genera Litokoala or Nimiokoala (Louys et al. 2009). It seems likely that specialisation on Euclayptus may only have developed with the modern genus Phascolarctos, corresponding with the rise of eucalypt dominance in the Australian flora in the late Miocene. As well as being potentially less specialised, the fossil genera of koalas were also distinctly smaller than the living species. Koala evolution reached an apogee of sorts in the Pliocene and Pleistocene with the fossil species Phascolarctos yorkensis, which tipped the scales at nearly twice the size of P. cinereus (Long et al. 2002) (somewhat disappointingly, no-one seems to seen fit to present a fossil koala with the name of Katastaxarctos).

Koalas can be very vocal animals, using bellows and grunts as their main method of communicating. This video of a vocalising bull comes from here.

The specialisation of the modern koala is truly a remarkable thing. True exclusivity of diet seems to be a rarity among large terrestrial vertebrates (and as it can reach sizes of 20 kg, there is no denying that the koala is a large vertebrate). Many have their preferred delicacies but remain far from averse to the occasional variation (something that I really wish the ABC had been more aware of with that lorikeet article). Thus we have cattle gnawing on bones, cats eating grass, or deer killing and eating birds. Even the giant panda, perhaps the other specialist mammal most familiar to the general public, has been known to supplement its bamboo diet with roots and small animals. But the koala turns up its nose at almost anything other than Eucalyptus leaves—and usually only a small number of Eucalyptus species at that. The toughness of Eucalyptus leaves mean they require a great deal of digestive processing, and the small nutritive return is responsible for the extended periods of inactivity that koalas are known for. Early British naturalists often compared the koala to the South American sloth, which functions under similar constraints. The low nutrition of their diet is also reflected in the notoriously small brains of koalas, which have one of the smallest brains relative to body size of any mammal. So noxious is the eucalypt diet that koala joeys have to be weaned onto it through stages. When a joey is about six months old, its mother starts producing a faecal pap of half-digested leaves that the joey eats direct from her cloaca before moving to a more direct leaf diet about a month later.

Nevertheless, by specialising on Eucalyptus leaves, koalas have access to an abundant food source that few other mammals can handle. Even after the arrival of Europeans, koalas have handled the incursion of foreign predators better than many other Australian natives. The main threat to their continued existence is clearing of the forests on which they depend for food. The koala deserves its position as an icon, and an icon is worthy of respect.

ARKive video - Koala joey eating pap
Video of a koala joey feeding on pap, from Arkive.


Houlden, B. A., B. H. Costello, D. Sharkey, E. V. Fowler, A. Melzer, W. Ellis, F. Carrick, P. R. Baverstock & M. S. Elphinstone. 1999. Phylogeographic differentiation in the mitochondrial control region in the koala, Phascolarctos cinereus (Goldfuss 1817). Molecular Ecology 8 (6): 999–1011.

Long, J., M. Archer, T. Flannery & S. Hand. 2002. Prehistoric Mammals of Australia and New Guinea: One Hundred Million Years of Evolution. University of New South Wales Press: Sydney.

Louys, J., K. Aplin, R. M. D. Beck & M. Archer. 2009. Cranial anatomy of Oligo-Miocene koalas (Diprotodontia: Phascolarctidae): stages in the evolution of an extreme leaf-eating specialization. Journal of Vertebrate Paleontology 29 (4): 981–992.

Dot Snails

A dot snail Punctum pygmaeum crawls over a mountain bulin Ena montana (itself not a very large snail). Copyright Stefan Haller.

The dot snails of the family Punctidae are one group of animals that certainly lives up to their name. For the most part, these are absolutely tiny terrestrial snails, sometimes barely passing the millimetre mark. They are united as a family by anatomical features of their radulae and reproductive systems (Solem 1983), but they show a variety of external morphologies, from higher-spired trochoid forms to flatter discoid forms. They also vary in ornament, with some being fairly smooth but others marked with distinct ridges, in some cases with spiny extensions of the periostracum. Most punctids are found in leaf litter, in which they graze on microalgae and detritus. The diverse fauna of punctids on Lord Howe Island, however, includes at least two species, Dignamoconcha dulcissima and Allenella formalis, that are arboreal, found living on palm tree leaves (Stanisic et al. 2010). Molecular analysis supports the inclusion of punctids in a group of small pulmonate gastropods known as the 'endodontoid clade' (Wade et al. 2001).

Live individual of Paralaoma servilis, from Christensen et al. (2012). Scale bar = 1 mm.

One would expect that such tiny snails would be easily overlooked, and it would not be surprising to find them amongst the tally of species that have been transported outside their native ranges by humans. One species, Lucilla singleyana, is associated with greenhouses in Europe; though known there from the fossil record, it is believed to have become extinct at the end of one of the interglacial periods and been subsequently reintroduced from North America (Alexandrowicz 2010). Another species, Paralaoma servilis, is believed to have originally been native to New Zealand but has been transported around the world, with expanding populations in Australia, Europe, North and South America (Christensen et al. 2012). Seeing as the fauna of my native New Zealand has suffered a lot at the hands of exotic introductions, I have to confess to a certain satisfaction at the idea that we're giving our own back.


Alexandrowicz, W. P. 2010. Lucilla singleyana (Pilsbry, 1890) (Gastropoda: Pulmonata: Punctidae) in recent flood debris in the Beskidy Mts (southern Poland). Folia Malacologica 18 (2): 83–92.

Christensen, C. C., N. W. Yeung & K. A. Hayes. 2012. First records of Paralaoma servilis (Shuttleworth, 1852) (Gastropoda: Pulmonata: Punctidae) in the Hawaiian Islands. Bishop Museum Occasional Papers 112: 3–7.

Solem, A. 1983. Endodontoid land snails from Pacific islands (Mollusca: Pulmonata: Sigmurethra). Part II. Families Punctidae and Charopidae, zoogeography. Field Museum of Natural History: Chicago.

Stanisic, J., M. Shea, D. Potter & O. Griffiths. 2010. Australian Land Snails vol. 1. A field guide to eastern Australian species. Bioculture Press: Mauritius.

Wade, C. M., P. B. Mordan & B. Clarke. 2001. A phylogeny of the land snails (Gastropoda: Pulmonata). Proceedings of the Royal Society of London Series B 268: 413–422.

Australian Government Unveils Plan to Fix Australia's Conservation Crisis

The federal government revealed its proposal today to solve the conservation crisis in Australia, by ensuring populations of species are kept to an acceptable minimum, and preventing the description of new ones.

Prime Minister Tony Abbott has slammed the continued description of new species in the Australian flora and fauna, calling it "irresponsible" and "wasteful". "Australia already has more than enough species," he explained in a speech to the National Resource Optimisation Board. "All that these so-called new species do is take resources that could be more profitably used by the species that are already here". Responding to reports that over 500 new species had been described during the term of the last Labor government, Treasurer Joe Hockey commented that, "This is simply indicative of Labor's profligate attitude. Scientists should not simply assume that they are entitled to add new species to Australia's burden."

Abbott in particular accused the publishers of a monograph describing 45 new species of millipede in western Tasmania of being "blatantly political", explaining that "Australians will decide what species get to live in Australia". When the lead author of the monograph was asked whether he had had any political intent in his publication, he replied, "I didn't then. I do now."

When asked about rumours that the Liberal government planned to slash funding for endangered species, Abbott replied that, "It is not the responsibility of the government to fund the lifestyle choices of species that allow themselves to become endangered. Fortunately, we have devised a plan that will allow us to build up the population numbers of so-called endangered species for considerably less expense than any of Labor's hare-brained schemes. Any species complaining of a shortage of individuals will simply have individuals reassigned to it from another, more abundant species." As an example of his plan, Abbott exhibited a brushtail possum that had recently been rebranded as a western quoll. When asked whether he thought his plan would be passed by the senate, Abbott replied, "Unfortunately, the senate continues to refuse to accept the results of the last election and the mandate given to us by the Australian public. Nevertheless, we are confident in our abilities to get this legislation through. Ricky Muir has been presented with a Mustang GT, and Jacqui Lambie has been promised that we will fix the loose tile in the Senate ceiling."

The Minister for Science was not available for comment.