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Mozambique Diary: Amphisbaenians

Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Having drawn the short straw at the phenotypic lottery I have always felt a special kinship with creatures that most people dismiss as too small, too creepy, too unattractive. Because these are (I tell myself) the hallmarks of the truly interesting organisms, ones that have followed the less-trodden paths of unusual specialization, remarkable adaptations, evolutionary ingenuity.

One such organism, about the existence of which I learned as a young child from an old zoology textbook, was Bipes, an amphisbaenian. It was a chimeric, strange creature, with the appearance of a pink snake, but equipped with a pair of shovel-like legs at the front end of its long body. There was a striking resemblance between that creature and a picture of a dragon that I had seen in the illustrated edition of the Old Testament from my Sunday School (which, incidentally, offered its classes on Monday nights), and I was instantly hooked.

Although it looks like a soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Although it looks soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Amphisbaenians are reptiles, but so unusual that for the longest time they were considered a separate order of these animals. For one, they look nothing like a vertebrate – the last couple of times that somebody brought me an amphisbaenian they were under the impression of having collected an earthworm (unlike Bipes, most species are legless.) Their annulated body is usually pink or covered with irregular, white and dark blotches, a clear indication that these animals don’t care about how they are perceived by others. And for a good reason – why bother with the looks if your entire life is spend underground and you yourself are blind. Better to invest the energy that would have been spent on the irrelevant appearance into things such as a thick skull and powerful thoracic muscles that will allow the animal to push effortlessly though the soil in search of prey.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

Recent phylogenetic studies revealed that amphisbaenians are not a separate, primitive order of reptiles, but rather a highly derived, supremely modified lineage of lacertiform lizards. It is very likely that the next step in this transition to a subterranean lifestyle was the complete loss of limbs and girdles, a dramatic reshaping of the skull, the loss of eyelids and, eventually, the emergence of a brand new group of animals, the snakes. In fact, the most basal (primitive) snakes, the Typhlopidae and other related families, look remarkably like the amphisbaenians.
A few days ago I was in the southern part of Gorongosa, checking out sites for the second biodiversity survey of the park, and there, in a dry, crumbling log, I found a beautiful little amphisbaenian, Chirindia swynnertoni. This species is rarely seen, and thus I promptly followed a recommendation of a field guide to amphibians and reptiles of East Africa: “Anyone finding a worm-lizard [amphisbaenian] should take it to a museum.” I still haven’t had the heart to preserve it for the Gorongosa Synoptic Collection, and instead I have been watching it for days, transfixed by its amazing ability to squeeze into the hardest soil with the body that looks like an overcooked string of pasta, and with a baby-pink face of a newborn. It has been feeding on termites and ant larvae, crushing the insects with its tiny yet powerful jaws. And I find it fascinating (and somewhat rewarding) that from so seemingly unassuming a beginning came a lineage of animals that has terrified the human psyche since the time of Eden.

Gorongosa amphisbaenian (Chirindia swynnertoni)

Gorongosa amphisbaenian (Chirindia swynnertoni)

Mozambique Diary: Blind snakes of Gorongosa

A comparison of the largest blind snake of Gorongosa, the Giant blind snake (Megatyphlops schlegelii), and the smallest one, the Peter's thread snake (Leptotyphlops scutifrons)

A comparison of the largest blind snake of Gorongosa, the Giant blind snake (Megatyphlops schlegelii), and the smallest one, the Peter’s thread snake (Leptotyphlops scutifrons)

Last night’s downpour flushed out a lot of things from under the ground, and one of them was a large blind snake, Megatyphlops schlegelii, which I found as it was swimming in a puddle in front of the Scientific Services’ trailer. Now, large is a relative term – the snake is only a little over a foot long and as thick as a finger, but for blind snakes this is huuuge. Blind snakes, families Typhlopidae and Leptotyphlopidae, comprise some of the smallest reptiles, and definitely the smallest snakes, in the world. In fact, one species, Ramphotyphlops braminus, has spread over the globe with potted plants, mistaken for a small earthworm in the soil.

Both families are considered some of the most basal lineages of snakes, which means that their morphology and behavior gives us some insight into how snakes evolved from their closest relatives, lizards (or, more specifically, clade Toxicofera, which includes monitor lizards, agamas, and a few other groups). They are all subterranean and their morphology reflects this fact in the small but massively calcified skull, hard “beak” made of thick scales that allows them to push through the soil, and incredibly smooth body that minimizes frictions as they tunnel underground. The eyes are vestigial, hidden under semi-translucent scales, and are visible only as darker, light-sensitive spots on the sides of the head. Unlike other snakes they also lack a distinct tail – the body pretty much ends in a cloaca and all that remains of the tail is a tiny, sharp spike, their only defensive weapon.

The morphology of the Giant blind snake (Megatyphlops schlegelii) reveals its perfect adaptation for subterranean life – there is no neck or distinct tail, which means that the animal can move as easily forward as backward in the underground tunnels; notice the sharp defensive spike on the end of the body.

The morphology of the Giant blind snake (Megatyphlops schlegelii) reveals its perfect adaptation for subterranean life – there is no neck or distinct tail, which means that the animal can move as easily forward as backward in the underground tunnels; notice the sharp defensive spike at the end of the body.

Needles to say, blind snakes are completely harmless. They produce no venom and may even lack teeth in either the upper or lower jaw. When caught they try to jab the attacker with the tip of the tail, which is about as effective a defense as being licked by a puppy. Still, the first Megatyphlops I saw in Gorongosa was an animal being hacked to bits by villagers afraid of its (imaginary) venom.

The body of blind snakes is glossy smooth, reducing friction when moving underground. It also makes holding them in your hand rather difficult.

The body of blind snakes is glossy smooth, reducing friction when moving underground. It also makes holding them in your hand rather difficult.

So far I have found three species of blind snakes in the park, usually while flipping rocks when looking for crickets. Interestingly, I have also seen them frequently on the surface at night, moving slowly and deliberately, as if looking for something. These snakes feed mostly on termites and ants, the nests of which are often located under rocks and logs. I imagine that it is easier for the snakes to move on the surface to the next rock, than to plow under the surface, which may explain their behavior. Some blind snakes are known to produce pheromones that mimic those of their prey, thus protecting them from attacks by soldier termites and ants. Their feeding mechanism is different from that of other snakes – more evolutionarily derived snakes swallow the prey by alternatively advancing the left and right upper jaw arches (which can move independently) over the prey. But blind snakes don’t have long, independently movable upper jaw and instead “rake” their insect prey into the mouth by stretching and pulling back their short lower (Leptotyphlopidae) or upper (Typhlopidae) jaw. Apparently, smaller species may not even swallow the prey at all, but instead suck the liquid portion of the insect’s body and discard the exoskeleton.

Peter's thread snake (Leptotyphlops scutifrons), the smallest snake in Mozambique.

Peter’s thread snake (Leptotyphlops scutifrons), the smallest snake in Mozambique.

Mozambique Diary: Poetic justice

The Cape centipede-eater (Aparallactus capensis) from Gorongosa National Park, Mozambique

The Cape centipede-eater (Aparallactus capensis) from Gorongosa National Park, Mozambique

If we lived in an ideal world, right about now I would have been putting on my headlamp to begin stalking katydids in the luxuriantly green savannas of Gorongosa National Park. But, alas, we don’t. For reasons beyond my control I had to postpone a trip to Mozambique, although I hope to be able to get there within the next couple of months or so, and witness the park in its full, rainy season splendor.

When I was in Gorongosa in May, conducting a biodiversity survey of the Cheringoma Plateau, I was introduced by our intrepid herpetologists, MO Roedel and Harith Farooq, to an interesting little snake. The Cape centipede-eater (Aparallactus capensis), feeds, as the name suggests, exclusively on centipedes. These arthropods are not the friendliest of creatures, in fact I have a very healthy dose of respect for these powerful, blindingly fast predators. All centipedes are venomous and those large enough to be able to puncture human skin can deliver nasty, nasty bites. Their body shape, however, seems to make them ideal prey for snakes – they are long and thin, and a single centipede would nicely fill a snake of comparable size.

Aparallactus hunts by grabbing the victim in the middle of the body and slowly working its way towards the head, eventually swallowing the centipede head-first. The scales on this snake’s body are particularly hard, making it difficult for the centipede to sink its fangs (forcipules) into the reptile. At the same time the snake’s venom quickly subdues and kills the prey. Aparallactus belongs to a lineage of snakes known as side-stabbing snakes (Atractaspididae), which includes several deadly venomous species. But despite being powerfully venomous, centipede-eaters are not dangerous to humans as their short fangs are located in the back of the jaw and cannot reach the surface of our skin; one of the members of the genus, Aparallactus modestus, is even entirely fangless and feeds mostly on earthworms.

I have read that Aparallactus are immune to venom of their centipede prey, but the same cannot be said of other snakes found in Gorongosa. One rainy night on Mt. Gorongosa I ran across a scene that reinforced my high opinion of these multi-legged invertebrates: a large centipede was efficiently chomping to bits a House snake (Lamprophis capensis). If this is not the best example of poetic justice then I don’t know what is.

Centipede (Ethmostigmus sp.) devouring a House snake (Lamprophis capensis)

Centipede (Ethmostigmus sp.) devouring a House snake (Lamprophis capensis)

A portrait of a marine iguana

Sharlena Wood, a Canadian artist whose beautiful paintings have already been featured on this blog (here and here), did it again. Using a charcoal drawing technique she produced an outstanding portrait of a marine iguana by imaginatively reinterpreting one of my photos from the Galapagos Islands. This drawing is part of a series of portraits of endangered animals, which you should see in its entirety. And while there, look at Sharlena’s other art, you will not be disappointed.

Iguana

Amblyrhynchus

Mozambique Diary: On the benefits of being lazy

A Gorongosa crocodile sliding into the Urema River.

A Gorongosa crocodile sliding into the Urema River.

Since I needed for one of my book projects a few shots of the famous Gorongosa crocodiles, which rank among the largest in Africa, I asked for help from Bob Poole, a man with considerable crocodile experience. Bob is a legendary National Geographic cameraman who shot, among other NatGeo titles, “Africa’s Lost Eden” and “War Elephants.”
We decided to set up a blind near one of the crocodiles’ basking beaches on the night before, arrive when it was still dark and sneak into the hide, and photograph the animals from there. But we both felt a bit lazy, and in the end did not leave the camp until the late morning, when the sun was already up.

Bob Poole holding all that remains of his hide, and his tripod dragged into the river by a crocodile.

Bob Poole holding all that remains of his hide, and his tripod dragged into the river by a crocodile.

When we got to our spot we found an empty beach, with not a trace of the hide. Or rather, all that we found were traces of the hide, which had been ripped off its stakes still embedded in the ground, and dragged under water by an enormous crocodile. Luckily, the beast did not take Bob’s tripod, which we found in the mud nearby.

I am not a morning person, and never in my life did I feel more grateful for that. Had we been in the hide before dawn as planned, there is no telling how our little adventure would have ended. I think I will continue sleeping in.

Tracks of the crocodile that took, and most likely ate, our hide.

Tracks of the crocodile that took, and most likely ate, our hide.

Mozambique Diary: The Lizard Quest

Harith Farooq holding a Rock monitor (Varanus albigularis). These enormous lizards are some of the largest reptilian predators of Gorongosa, surpassed only by fully grown rock pythons and crocodiles.

Harith Farooq holding a Rock monitor (Varanus albigularis). These enormous lizards are some of the largest reptilian predators of Gorongosa, surpassed only by fully grown rock pythons and crocodiles.

Sitting on the dusty floor of a makeshift laboratory tent Harith Farooq carefully folded a piece of fine, steel mesh into a foot-long cylinder, then weaved in a stretch of a thick wire along its edge. Finally, he carefully attached a neck of an empty water bottle to one of the ends and looked at the contraption in his hands with deep concentration. “Something is still missing”, you could almost hear him think, “but what? A battery? A fork? Some gasoline, perhaps?” His gaze shifted to a stack of paper mouse traps covered with thick, sticky glue, the kind that was meant to immobilize any animal unlucky enough to step onto it. “Bingo!” – Harith picked one up and squeezed it into the tubular apparatus. “The perfect leezard trap”, he announced proudly.

Swynnerton's amphisbaenian (Chrindia swynnertoni), a subterranean blind lizard, found only in Gorongosa and a small surrounding area.

Swynnerton’s amphisbaenian (Chrindia swynnertoni), a subterranean blind lizard, found only in Gorongosa and a small surrounding area.

For the last few days Harith, a Mozambican scientist from the University of Lúrio in Pemba and his colleague MO Roedel from Berlin, two herpetologists participating in a biodiversity survey of the Cheringoma Plateau in Gorongosa, had been trying to catch some of the many lizards found in the Nhagutua Gorge, the site of our first camp. Alas, the sneaky reptiles proved to be extremely difficult to catch by hand, which prompted Harith to come up with an alternative solution. As the survey progressed his traps kept growing larger and more complex, combining both natural materials (rocks, sticks, bark) and man-made objects – a plastic sheet, twine, wire and, of course, steadily increasing amounts of glue. The one thing that they all had in common was their total inability to capture even a single reptile.

Flap-necked chameleon (Chamaeleo dilepis) is common in the savanna woodlands of the Cheringoma Plateau

Flap-necked chameleons (Chamaeleo dilepis) are common in the savanna woodlands of the Cheringoma Plateau

The strangest part was that Harith was incredibly good at catching reptiles, or any other organisms, without the need for additional accessories. I had never seen anybody catching, with their bare hands, a giant centipede, a solifugid, or a deadly spitting cobra, but Harith caught them all, while carrying a casual conversation. In the end, during the Cheringoma survey he and MO collected 47 species of lizards and snakes, effectively quadrupling the number of reptiles known from Gorongosa National Park.

Within a three week period in Gorongosa our team of biologists was able to document the presence of all nine families of lizards that occur in southern Africa. Among them were some real gems, including an entirely blind, subterranean lizard, the Swynnerton’s amphisbaenian (Chrindia swynnertoni). These tiny reptiles, known only from a handful of specimens recorded around Gorongosa, spend their entire life underground, leading a lifestyle remarkably similar to that of earthworms, and feeding on termites and ant larvae.

Thunderbolt lizard (Nucras sp.), one of the fastest animals found in Gorongosa.

Thunderbolt lizard (Nucras sp.), one of the fastest animals found in Gorongosa.

On the opposite end of the lizard spectrum, two species of giant monitors (Varanus) turned out to be quite common on the Cheringoma Plateau. One day Harith walked into the camp carrying a live Rock monitor (V. albigularis) the size of a goat, which he had captured by throwing himself on top of the gargantuan animal, barely overpowering it with the help of two other people. The reptile’s snout was still covered with blood of the last victim, probably a bird or a small child, by the looks of it, and gazing into the monitor’s eyes made me realize how grateful I was that our species appeared long after the era of dinosaurs had passed. We released the beautiful creature after examining it for the presence of external parasites, which the lizard had none, proving its excellent health condition.

Plated lizard (Gherrosaurus major) was one of the most exciting finds of the survey.

Plated lizard (Gherrosaurus major) was one of the most exciting finds of the survey.

Almost every day our herpetological team, which also included a Mozambican student Francisco Domingos, recorded something new and exciting. Often it was a tiny brown frog that differed from all other frogs by the presence of a slightly enlarged corner of the left supraocular cuticular fold, which was enough to make our herpetologists prance and giggle with excitement like little girls. But at other times it was a vine snake that could kill you with a half a drop of its venom, or a spiny rock lizard that defends itself by squeezing into rock crevices and inflating its body like a balloon. The survey found charismatic chameleons, among them the famed pygmy chameleon of Mt. Gorongosa, unquestionably the cutest lizard in Mozambique, and blindingly fast lacertid lizards with flame orange tails, which looked like tiny thunderbolts zipping across the ground.

The survey officially ended yesterday, and Harith is on the way back to Pemba. Data collected by him and the rest of the herpetological team will be added to the ever growing Gorongosa biodiversity database, a powerful tool that helps manage the restoration efforts in the park. I was sorry to see the members of the team depart, but having witnessed Harith handle cobras and puff adders as if they were harmless puppies I was relieved to see him leave the park, still alive and well. All things considered, a gash in his finger, courtesy of a pouched rat, followed by a nip from a giant scorpion hardly count as injuries.

The male of the Gorongosa girdled lizard (Cordylus mossambicus) looks like an alligator wearing an orange T-shirt. These spectacular lizards are found only in a small area around Gorongosa and the neighboring Chimanimani Mountains of Zimbabwe, and are threatened by habitat loss and overcollecting for pet trade.

The male Gorongosa girdled lizard (Cordylus mossambicus) looks like an alligator wearing an orange T-shirt. These spectacular reptiles are found only in a small area around Gorongosa and the neighboring Chimanimani Mountains of Zimbabwe, and are threatened by habitat loss and overcollecting for pet trade.

Mozambique Diary: Is this tortoise broken?

An adult Hingeback tortoise (Kinixys belliana) from Gorongosa. What looks like a wound on its carapace is a flap of skin that allows the shell to close and protect the hind legs and tail.

An adult Hingeback tortoise (Kinixys belliana) from Gorongosa. What looks like a wound on its carapace is a flap of skin that allows the shell to close and protect the hind legs and tail.

Some time ago I was driving in Gorongosa when I noticed a large tortoise laying in the middle of the road, stuck upside down in the mud. The animal was alive but had what appeared to be a large wound in the posterior part of its cracked carapace. There were fresh tracks of a civet all around it in the mud, and I assumed that the civet found an injured tortoise (I didn’t think a civet could do it itself) and was hoping to eat it. I pulled the animal out of the muck and only then recognized what I was looking at – the tortoise was not injured at all, and what I took for a wound was a flap of skin that connected the front part of the shell with its movable back. Because it was not an ordinary tortoise, but a Hingeback tortoise (Kinixys), a member of a remarkable group of reptiles that are capable of closing shut the back of their shells to protect the hind legs and the tail. This, combined with the head tightly pulled into the front of the shell and blocked by its heavily armed front legs makes the hingeback tortoise virtually immune from attacks by smaller predators. Judging by the dense trail of civet tracks around the tortoise it seemed that the mammal had spent a lot of time in frustration, unsuccessfully trying to get to the soft parts of the reptile.

A juvenile Hingeback tortoise; its hinge is not yet developed.

A juvenile Hingeback tortoise; its hinge is not yet developed.

Although the movable carapace is a great way to protect the rear part of the body, the flap of skin that connects the two components of the carapace is a favorite location for another enemy of the tortoises to attack – the ticks. Every tortoise I found in Gorongosa carried several huge, heavily armed ticks (mostly of the genus Amblyomma), whose body shape and sculpturing was surprisingly similar to that of the tortoise. Carrying a bunch of blood-sucking ectoparasites is no fun, but the burden of being drained by them is probably particularly heavy on smaller, younger animals. A few days ago I found a tiny Hingeback tortoise, one whose hinge was not yet fully developed, and it carried on its leg one of the largest ticks I have ever seen. It was as if I had a parasite the size of a football permanently attached to my body. I removed the tick from the tortoise, put one of the animals into a vial of alcohol, and applied some antiseptic to the other and let him back on his merry way.

An enormous tick (Amblyomma sp.) on the tortoise's leg.

An enormous tick (Amblyomma sp.) on the tortoise’s leg.

Hingeback tortoises are quite common in Gorongosa, and I see them often as they cross the network of trails. But across Africa their numbers are declining as the result of habitat loss and collecting for the pet trade. Every year about 20,000 of these animals are exported to be sold in pet stores in the US and Europe, and Mozambique alone sends out about 3,000 of these animals every year (this is the official quota allowed by CITES, the actual number is undoubtedly higher). Luckily, recently the importation of most of Hingeback species was banned in the US. The reason – ticks. Some of the ticks carry a disease which, while not harmful to the reptiles, is often fatal to cattle – the Heartwater disease, caused by rickettsia Ehrlichia ruminantium. And so, the same parasite that makes the tortoises’ life miserable may in the end help them survive in the wild. I guess you never know who your true ally is.

Tortoise tick (Amblyomma sp.) actually looks like a tortoise, and its opisthosma is almost as hard as the reptile's shell.

Tortoise tick (Amblyomma sp.) actually looks like a tortoise, and its opisthosma is almost as hard as the reptile’s shell.