The Mount Mulanje Pygmy Chameleon

DSCF7127 - pygmy chameleon small
Rescuing the Mulanje Pygmy Chameleon from the path.
Christine Cambrook | CC BY-NC-SA 4.0

By far the rarest animal that I have encountered during my time in Mozambique has been the Mount Mulanje Pygmy Chameleon, Rhampholeon platyceps. A stunning little creature, it is endemic to the Mulanje massif, only being found in the southern and eastern-facing mid and high altitude evergreen forest of the massif. This includes the Ruo Gorge, where we came across the little guy (or possibly girl) above. Unfortunately its forest habitat remains only in fragmented patches and, due to its restricted range and the high threat of deforestation, it is declared Endangered by the IUCN Red List. We were lucky that this individual was crossing the path in front of us.

The Mulanje Pygmy Chameleon was first described in 1892 in a paper by A. Günther to the Zoological Society of London. The paper is titled Report on a Collection of Reptiles and Batrachians transmitted by Mr. H. H. Johnston, C.B., from Nyassaland and is available for free here. Like many papers of the day, Dr Günther was communicating the findings of others and it opens with a description of the people involved in what today might be considered equivalent to an author list:

Acting under instructions from Mr. H.H. Johnston, C.B., F.Z.S., Mr. Sclater has sent to the British museum a series of specimens of Reptiles and Batrachians collected by Mr. Alexander Whyte, F.Z.S., the naturalist attached to Mr. Johnston’s staff, in the Shire Highlands of south of Lake Nyassa, principally upon Mount Zomba and Mount Milanji.

This scientific description in a zoological journal misses out the context of this discovery. In 1982 the British Central Africa Protectorate, what is now Malawi, was only a year old. Mr. Harry H. Johnston was sent to the region by the British just three years earlier, in order to negotiate with the Portuguese to protect British interests and prevent Portuguese occupation of the area. (Later, Sir) Harry Johnston was an explorer and a politician, a fixture in the seven major European powers’ Scramble for Africa, negotiating treaties with local chiefs to establish Malawi as British territory. He later became the British Central Africa Protectorate’s first Commissioner. However, Johnston was also a naturalist and this paper demonstrates some of the work that his team did to categorise the fauna of the area.

Unfortunately, Johnston’s labelling of the location of collected species was sometimes imprecise – the specimens described in this paper are labelled as being collected in the Shire Highlands, a 7,300 km2 plateau in southern Malawi which includes Mulanje, Blantyre, some 75 km to the west, and Zomba, some 50 km to the north. The confusion caused by this poor location label probably caused later biologists to describe a sub-species for the same animal. These biologists collected specimens from the Lichenya Plateau and Ruo Gorge and seemingly saw enough differences to define two sub-species, Rhampholeon platyceps platyceps and Rhampholeon platyceps carri. Later analysis resolved this separation.

The original paper is full of descriptions of animals “new to our knowledge of the Reptilian Fauna of the Nyassa district”. The beautifully detailed sketch on plate 34 of the pygmy chameleon (labelled #1. A different species, #2, is also sketched) demonstrates the chameleons in their assumed habitat. Notice the absence of the tail, honestly described in the text as being “lost by accident”.

sketch of rhampholeon platyceps
Oops. The tail’s missing. 
Günther (1892)

“pairs of very small tubercles are placed at regular distances along the vertebral line”

The distinguishing tubercles are clear in the following photo, a thin line of green-grey along its back of its greyish brown body. Head-on you can see that Dr Günther’s simple sketch of the head was just right, with the characteristic triangle shape on the head clear in the photo. The bulging black eyes are reminiscent of the compound eyes of flies.

IMG_1220 - pygmy chameleon adjusted
Getting a close up.
Andrew Beale | CC BY-NC-SA 4.0

Back on the forest floor you can appreciate the famous camouflage ability of chameleons. The Mulanje Pygmy Chameleon might not be as vibrant as some species (see the Panther Chameleon for an impressive display) but it certainly can blend in with its surroundings. Marching up the Big Ruo path on our way to Minunu Hut, I’m sure we would have never had seen it had it been in the leaf litter to the side.

IMG_1212 - pygmy chameleon on ground
Back down on the forest floor.
Andrew Beale | CC BY-NC-SA 4.0

Since this animal was first described in the scientific literature, the world around them has changed, and not to their benefit. The population of Malawi has risen from approximately 700,000 to 16,500,000, and is projected to rise to 45,000,000 by 2050, putting huge pressure on the land and consequently on the chameleon’s habitat. World Bank data shows that between 1990 and 2010 the population increased by 50 % (9,408,998 to 14,769,824) and, in the same time, forested area decreased by 17 %. The Mulanje massif is experiencing the full extent of the deforestation and the Ruo Gorge, where we found this particular chameleon, is one of the few remaining patches of rainforest (which also makes it a beautifully cool route up to the plateau). Another species unique to Mulanje, the Mulanje cedar tree Widdringtonia whytei, is critically endangered – a toxic combination of demand for its timber and the poor growth of infant trees when surrounded by other plants. Both these species are losing the competition for space with the surrounding human population, an imbalance that groups such as the Mount Mulanje Conservation Trust are working to address.

Recently, pygmy chameleons closely related to the Mulanje Pygmy have been described from Mozambican “sky islands” just over the border from Mulanje. These “sky islands” are, like Mulanje, isolated inselbergs of erosion-resistant rock and rise out from the planes beneath them like islands in the sky. Mt. Chiperone, Mt. Mabu, Mt. Namuli and Mt. Inago range from 50 to 200 km from Mt. Mulanje and harbour similar evergreen rainforest habitats as can be found on Mulanje. In 2014, Branch and colleagues described four newly discovered pygmy chameleon species, isolated from one another by their restriction to evergreen mountain rainforest. All within the same genus as the Mulanje Pygmy Chameleon, Rhampholeon maspictus (Mt. Mabu), Rh. nebulauctor (Mt. Chiperone), Rh. tilburyi (Mt. Namuli) and Rh. bruessoworum (Mt. Inago) are examples of allopatric speciation – speciation that occurs as populations become isolated from one another.

The speciation hypothesis could be this. These mountains were once connected as part of a large plane. They became mountain islands due to their geological composition, resisting the erosion of the surrounding planes. As the montane rainforest habitat became restricted to the remaining high lands, so too did the ancestral pygmy chameleon that once inhabited the whole area. Over time the multiple populations of this single species diverged, enough to become reproductively isolated from one another, becoming new and separate species. If this was the case, we might expect that the evolutionary relationships between chameleons inhabiting current day mountains to related to the geographical distance between them. This is indeed what was found by Branch and colleagues – chameleons on Mt. Inago appear to have diverged first (ca. 11-20 Mya), followed by those on Mt. Mulanje and Mt. Namuli (ca. 6-16 Mya), followed by chameleons from Mt. Mabu, Mt. Chiperone and Malawi Hills (Rh. chapmanorum) which appear to have diverged from each other more recently (4-9 Mya). This reflects the geographical distance between the mountains and the present of geographical boundaries (such as rivers).

Mountains of Zambezia3
The mountains surveyed and Mt. Tumbine, another 1500m+ peak.

The four surveyed mountains were chosen based on a Google Earth search of the area to find large (greater than 5000 ft or 1500 m) isolated mountains in Mozambique similar to Mulanje. Mount Tumbine, which rises above the town where I live, Milange, was not included. While not as big as Mts Namuli, Inago or Chiperone, it still rises over 1500 m and has patches of rainforest similar to those in the Ruo Gorge. Tumbine is close to Mulanje, just 3.5 km separates the 900 m+ parts of the mountain, but it is isolated from Mulanje by a river, the Malosa. Could Mt. Tumbine also have a resident population of pygmy chameleons and, if so, do they form a different species to the others? Only an expedition will tell…

Featured research:

Günther, (1892), Report on a Collection of Reptiles and Batrachians transmitted by Mr. H. H. Johnston, C.B., from Nyassaland, Proceedings of the Zoological Society of London

Branch et al., (2014), Pygmy chameleons of the Rhampholeon platyceps compex (Squamata: Chamaeleonidae): description of four new species from isolated ‘sky islands’ of northern Mozambique, Zootaxa

Do we have the right to eradicate species?

While living in Mozambique I have seen first-hand the tremendous suffering caused by mosquitoes and the diseases that they transmit, especially in children. Friends have lost children to malaria and, in this rainy season especially, neighbours are frequently coming down with the disease. According to the Gates Foundation, malaria, transmitted by the mosquito Anopheles gambiae, caused 627,000 deaths in 2012. It’s a scourge to the human race. When you add in dengue and chikungunya, two other mosquito-borne diseases, and the strong (but not yet conclusive) association between the zika virus and microcephaly, mosquitoes become the animal incarnation of the Grim Reaper.

IMG_20160211_111701888
A happy sight? A dead mosquito

Nevertheless, I was shocked to read an article in the Guardian in which so many ecologists, entomologists, parasitologists would have no problems with “wiping them off the face of the earth”.

A few quotes:

  • Professor Steve Lindsay, a public-health entomologist at the University of Durham agrees: “I have no problem with taking out the mosquito.”
  • Professor Hilary Ranson, head of vector biology at the Liverpool School of Tropical Medicine. “I spend most of my time trying to keep them alive and study them, but that’s in order to try to kill them. Ultimately I wouldn’t be too sentimental.”
  • Jules Pretty, professor of environment and society at the University of Essex: “Here you can ask the question: if there was a loss of a whole species, would there be a human benefit? And in this case, the human benefit is so great that I think you have to say: ‘OK, I can hold these two thoughts at once.’”

These are really quite strong statements. And for the most part I see where they are coming from. The human argument against mosquitos (or the diseases that they carry) is very strong – you only have to look at the number of deaths they cause, the suffering from the diseases, the long term effects of the disease. The economic argument is strong, at least in terms of man-hours and productivity loss because of illness – estimated at billions of dollars every year.

An estimated 207 million people suffered from the disease in 2012, and about 627,000 died. About 90 percent of the deaths were in Sub-Saharan Africa, and 77 percent were among children under age 5.

Gates Foundation

If we did eradicate them, wouldn’t ecology suffer? A pitcher plant in the north east of America, benefits from the micro-community including mosquito larvae that lives in its leaves, as they make nutrients such as nitrogen available for the plant. The mosquitofish Gambusia affinis, a specialised predator of mosquitoes, could go extinct without mosquitos to feed on. This loss could have major effects up and down the food chain. A primary food source of insects, spiders, salamanders, lizards and frogs would be lost and the migratory birds that fly through the Arctic tundra would no longer benefit from the vast summer swarms of mosquitoes. Also, mosquitoes do pollinate plants. But, in most cases, the ecological role played by mosquitoes is actually small, and according to a report in 2010, other species could fill in – birds would switch to other swarming flies that would fill that niche, and other organisms could step in to process detritus in water systems. The evidence suggests that ecology wouldn’t suffer that much, unlike if, for example, bees go extinct. So the ecological argument for keeping mosquitoes is not strong. As one article is titled, “What Purpose Do Mosquitoes Serve? It’s hard to justify the existence of these annoying critters.”

It seems very clear: eradicating mosquitoes isn’t just a good thing to do for humanity, it also isn’t too bad for the world either.

Salticidae_eating_mosquito_2012_03_05_3574
One animal that might have to find a new dinner menu if mosquitoes were no more – a female jumping spider. CC BY-SA 3.0 | JonRichfield

A couple of thoughts:

One. It isn’t the mosquitoes that kill people, it is the diseases they carry. Malaria kills people, not Anopheles gambiae. The Gates Foundation defines malaria eradication as “removing the parasites that cause human malaria from the human population. Simply interrupting transmission is not sufficient to achieve eradication”. Sure, it might be easiest to eliminate malaria by eliminating A. gambiae but we should bear in mind that it’s not A. gambiae that kills. I can testify to how annoying they and how much their bites itch (and Aedes aegypti‘s bites are even more painful) but that isn’t a reason to eradicate them.

Two. A comment on the Guardian article: “If we eradicate the mosquito what vehicle will death find to replace it?”. If other species will fill in mosquitoes ecological role with ease, then other species will surely become the vectors of deadly diseases. A Conversation piece on the eradication of mosquitoes concludes with the same thought.

Three, and perhaps my strongest objection to the sentiment in the Guardian article. Even if mosquitoes were, as far as we could work out, ecologically ‘useless’ and even if it was guaranteed that eradicating them would also eradicate malaria, Dengue and zika, would it still be right to purposefully ensure entire species go extinct? Do we have the right to wipe that species off the face of the earth? I’m not sure. What would that mean for other ‘undesirable’ species? It’s a very dangerous place to go if we start rating which species we can eradicate. Who gets to make that decision? What checks and balances would there be? What do you think? Please make comments at the bottom of the page – I’m interested in your thoughts.

After all, “The ecological effect of eliminating harmful mosquitoes is that you have more people. That’s the consequence,” says entomologist Daniel Strickman, programme leader for medical and urban entomology at the US Department of Agriculture in Beltsville, Maryland. If you’re talking about species that are a menace to other species, serve little ecological ‘purpose’, and have done great damage to the ecosystems around them, then Homo sapiens should be worried.

 

Colourful Chameleons and Stripy Zebras – The Coolest Animals in Africa

You can say all you like about lions or elephants being the coolest animals in Africa. They are awesome for sure but they’re not quite the top. I suggest that that title goes to the chameleon and the zebra.

Why? They are just so unique: one changes colour as much as a fashion model, and the other has a coat pattern unlike any other mammal. And thanks to two papers released this year, we’ve begun to understand a bit more about their unique skin.

In the space of a few seconds, this guy went from brick (https://instagram.com/p/wEsq3JRnsn/?modal=true) coloured to plant (https://instagram.com/p/wEsT9RRnqJ/?modal=true) coloured as he attempted to blend in. Credit: @joannefbeale (https://instagram.com/joannefbeale/)
In the space of a few seconds, this guy went from brick to plant coloured as he attempted to blend in. Credit: @joannefbeale

Continue reading “Colourful Chameleons and Stripy Zebras – The Coolest Animals in Africa”