Kermit’s Doppelgänger: a new glass frog from Costa Rica

April 21, 2015 • 2:47 pm

Here’s a “ribbet-ing discovery”, a pun that comes from the Daily Mail. And, this time I did check the date on the research, and it is indeed new. The bad news is that I can’t access the journal Zootaxa (you can find three pages of the larger paper here, two of which are references), so I’m going on second-hand reports, which report the discovery of a new glass frog in the genus Hyalinobatrachium: H. dianae, which already has its own Wikipedia page. Here’s a screenshot of part of the first page, which gives the reference:

Screen Shot 2015-04-21 at 8.08.12 AM

The frog is getting attention because it supposedly looks like Kermit. You be the judge; I refer you to that eminent repository of biological research, The Daily Mail:

27AB9ED600000578-0-image-a-82_1429284333762 — (Daily Mail) A new species of glass frog has been discovered with translucent skin so you can see its insides. Hyalinobatrachium dianae (pictured) was found in the mountains of eastern Costa Rica and has a distinctive call.

Glass frogs are of course named after their renowned transparency, which this one shares:

27AB9EDD00000578-0-image-a-83_1429284336030 — (Daily Mail): The animal’s heart, liver and gastrointestinal tract are easily visible (pictured) thanks to translucent skin on its under side. It’s distinguishable from other glass frogs which have this strange characteristic, by its long toes and black and white eyes

Screen Shot 2015-04-21 at 2.34.15 PM — (Daily Mail): H. dianae stands out from other glass frogs because of its unusual black and white eyes (pictured left), which are similar to those of Kermit the Frog, of the Muppets (pictured right) in that they face forward

The Mail reports (hey, I’m happy that they give this much biological information in a tabloid!):

Scientists were surprised to stumble across the frog, given that a through survey of the region was conducted late last century, and reported their find in the journal Zootaxa.

The frog was named by Brian Kubicki who discovered it, after his mother Janet Diana Kubicki to thank her for supporting his interest in science, Costa Rica’s Tico Times reported.

. . . Lead author of the study, Dr Kubicki said: Its advertisement call is quite unique…It’s different than any other species that has been discovered.’

The study says the frog’s ‘advertisement call’ consists of ‘a single tonal long metallic whistle-like note with a duration of 0.40–0.55 s… and a dominant frequency of 3.35–3.44 kHz’.

It’s likely the frog uses it to find a mate in the mountain forests.

Dr Kubicki said that the amphibian sounds more like an insect than a frog, which may explain how experts missed it during their extensive survey.

The frog also measures just one inch (2.5cm) long, making it relatively difficult to spot among the foliage in the west forests and rainforests of the Caribbean foothills of Costa Rica where it was discovered at elevations of between 1,312 ft to 2,624 ft (400–800 m).

And USA Today adds this:

Brian Kubicki said the small, semi-translucent specimen is delicate and “is a good indicator of the general health of the eco-system.” Kubicki named the frog “Hyalinobatrachium dianae” in honor of the senior author’s mom Janet Diane Kubicki, the Costa Rican Amphibian Research Center says.

Other authors include Stanley Salazar and Robert Puschendorf, according to the Center.

According to C|Net, the species has been given the adorable common name of “Diane’s Bare-hearted glassfrog,”

NBC News has a report with a video and this introduction:

A new species of frog found in the Central American country of Costa Rica is being compared to Jim Henson’s most famous Muppet and apparently the two look most alike in the eyes.

I love the note “the Central American country of Costa Rica,” as if most people don’t know where it is. But by “most people” I mean “most people in the world,” for Americans are notoriously ignorant about geography.

And here’s the video; click on the screenshot below to see it:

h/t: Chris

Readers’ wildlife photographs

April 21, 2015 • 8:15 am

We’ll start today with a birth announcement: the bald eagles Desi and Lucy have produced at least one chick, and maybe more. We have proof from the photographer and chick’s godparent, Stephen Barnard from Idaho. Here is the bouncing ball of fluff:

This morning [JAC: yesterday] I took the first clear photo of a chick this season. They’re so ugly they’re cute. I can’t tell whether there are more than one.

Alex MacMillan sent a whole variety of pictures from a whole variety of taxa, all taken in southwest Ontario:

Blue-Spotted Salamander, Ambystoma laterale. This salamander is common at Rondeau Provincial Park. The ambystomatid salamanders are known to have a unique breeding strategy. Many populations are all female and engage in what some biologists refer to as kleptogenesis in which the females mate with males from other species but only express the female genes, that is they ‘steal’ the males sperm. This complex consists of five different ambystomatid species and the individuals are all degrees of polyploid.

Coyote, Canis latrans. A coyote watches me from the middle of a farm field in early winter.

Eastern Fox Snake, Pantherophis gloydi. This is a large snake that is found near marshes along the great lakes. This particular snake I found at Hillman Marsh and was close to a meter long. I was alerted to its presence by the sound of angry Red-Winged Blackbirds mobbing it. This species does prey on birds, particularly nestlings. It also has a display in which it mimics a rattlesnake by rearing up and vibrating its tail.

Red Fox, Vulpes vulpes. A Red Fox at the side of the road as we drove through the country. A moment later it ducked under the fence and was gone.

Eastern Hog-Nosed Snake, Heterodon platirhinos. Picture taken at Komoka Park. Hog-Nosed Snakes have an upturned nose which they use to dig out their favourite prey, toads. They are known for their impressive displays. This one is flattening its head and neck as well as hissing and curling its tail. If that doesn’t work it will play dead. There are several different scale patterns in this species. It is also a rear-fanged venomous species; however, no human deaths have been recorded to my knowledge.

Eastern Garter Snake, Thamnophis sirtalis. This is a melanistic garter snake at Long Point Provincial Park. These melanistic garter snakes are common around Lake Erie.

melanistic garter lp

Queen Snake, Regina septemvittata. Queen snakes are very specialized and feed almost exclusively on newly molted crayfish. This individual was found at the Ausable River. I had been reading a book in which a biologist described finding Queen Snakes in abundance at a particular spot on the Ausable in the 1960’s. I went to check it out and sure enough around 50 years later I found several Queen Snakes in the exact same place.

Red-Headed Woodpecker, Melanerpes erythrocephalus. I am a big fan of Picids so I was very pleased to get a good shot of this Red-Headed Woodpecker at Rondeau.

Ring-Necked Snake, Diadophis punctatus. This small snake is a rear fanged venomous species, however I have never heard of one envenomating a human. This picture was taken at Inverhuron Provincial Park on Lake Huron.

Spiny Softshell Turtle, Apalone spinifera. Usually I only see the adult softshell turtles so when I saw this young turtle in the Thames River I scooped it up for a quick picture before letting it go. As soon as I put it back in the water it buried itself in the sand with just a bit of its head showing.

A new and bizarre shape-shifting frog

March 29, 2015 • 9:50 am

Instead of going to church today, we can have our special Alain de Botton-Approved Religion Substitute by worshiping at the church of Our Lady of Natural History. There is in fact a wonderful new discovery about frogs, one described in a new paper in the Zoological Journal of the Linnaean Society by Juan Guayasamin et al. (reference and free link below; there’s also a precis in LiveScience).

I can state the results concisely: the authors found a new species of frog in Ecuador that can dramatically change its body shape from spiky to smooth in a matter of only a few minutes. They then found another species, somewhat but not extremely closely related to the first, that can do the same thing. This kind of change in morphology, induced by the environment, is called phenotypic plasticity. And its observation in the frogs suggests two conclusions:

1. A lot more frogs can do this than have been described, but you need special conditions to see it, so it’s been largely undescribed. Other abilities of amphibians to change shape or color within a short time may also have been missed.

2. Since new frog species are often identified by their appearance after having been collected and pickled in alcohol, there may be described species that are identical to species with other names, but were misidentified because frogs collected at different stages of shape-changing could be mistaken for two different species. This is especially problematic because a large proportion of new species in both invertebrates and vertebrates (18% and 19%, respectively) are described from only a single specimen.

The paper gives other information as well, including genetic data, a phylogenetic analysis of the genus showing how the two shape-shifting species are related, other genetic information about differences between populations, and a description of the frog’s call and morphology, important for describing it as a new species. But those issues are of more professional interest and need not detain us.

In amphibians, most variation among individuals of a species is in color, but those differences are permanent (like hair and skin color in humans) and don’t change over time. Those traits that do change over time in amphibian species, like crests in newts or tubercules in frogs, change during the breeding season, usually in males as a way to attract mates, and then revert back after the season. They thus change seasonally rather than over just a few minutes, like the frog described in this paper. The rapidity of change in the species is thus novel.

The new species, Pristimantis mutabilis (note the species name!), was first spotted in 2006 in the cloud forests of the Ecuadorian Andes, but its ability to change shape wasn’t detected until three years later. Under normal conditions the frog is spiky, with tubercules and points, but it changes when they’re picked up. As the authors describe in the paper:

All individuals of Prismantis mutabilis presented a markedly tubercular skin texture when found on vegetation or hidden in moss during the night. Large tubercles were evident on the dorsum, upper and lower lips, upper eyelid, arms and legs. After frogs were captured, they all showed a sudden and drastic change in skin texture; all tubercles became reduced in size, and the dorsal skin became smooth or nearly smooth (i.e., few tubercles are visible, mainly on the upper eyelid and heel). When frogs were returned to mossy, wet en- vironments, they recovered a tuberculate skin texture. We speculate that explanatory variables involved in frog skin texture change are stress, humidity, and back-ground. Our observations do not support light availability as a source of texture variation as we observed skin texture change at day and night. The time rate of skin texture variation might depend on the variables mentioned above; we only have one quantitative measure, which is summarized in Figure 2.

Here’s Figure 2: As you can see, the spiky frogs become relatively smooth within five minutes after capture. It’s not yet clear what physiological/biochemical systems are involved in this dramatic change:

Here are two more pictures of individuals changing:

In this photo, from Figure 3, a sub-adult male is first photographed in its natural habitat (A) and then in the laboratory (B). You can see the change very clearly:

And here’s one more with the caption from the paper. These are small frogs, ranging in snout-vent length between 17 and 23 mm (0.7-0.9 inches):

The authors also identified another species that does the same thing: a congener (frog in the same genus) named Prismantes sobetes. Since the two shape-shifting species are not closely related—a phylogeny shows many other species are more closely related to either than the two are to each other—either the ability to change body texture has evolved twice, or it’s present in some of the intervening species since it evolved in a common ancestor, or it is the remnant of a feature in their common ancestor that has been lost in all other species in the group. Since we don’t know about the abilities of those other species to shape-shift, more work is needed to distinguish among these explanations.

This leaves one big question: Why on earth do the frogs do this? Let’s assume as a working hypothesis that the shape change is an evolved one, and that individuals that could change shape had a selective advantage in the ancestral lineage. (It’s also possible that this is simply a nonadaptive physiological response to stress.) The authors suggest, probably correctly, that the tubercles and spiky appearance help camouflage the frog in the cloud forest, where it often sits among moss, vegetation, and epiphytes (plants growing on other plants); and they also raise one possibility for how they change their shape:

We suggest that skin plasticity is associated with environmental camouflage rather than sexual selection or dimorphism. Pristimantis mutabilis and P. sobetes are geographically distributed in montane cloud forest habitats that are abundant in epiphytes, vegetation, and moss. In these habitats, skin texture that has the appearance of moss or detritus likely conceals the individual from visual predators, such as birds and arachnids. While the physiological mechanisms of how texture changes in such a short time are unknown, we speculate that it could involve allocation of more or less water to existing small structures (e.g. warts and tubercles) on the skin.

But what’s missing here is an explanation for the change itself, which I can’t find in the paper. That is, why do they change from the presumably camouflaged shape to a smooth shape? And here I, who have no knowledge about amphibians, come up short. Perhaps being smooth helps you escape from predators if you’re caught, or helps the frogs jump better. Experiments (some of them involving predation!) could help settle this. I suspect some readers who know more about frogs than I (I’m looking at you, Lou Jost) can suggest evolutionary reasons why shape-shifting may be adaptive. Please give your suggestions in the comments.

__________

Guayasmin, J. M. et al. 2015. Phenotypic plasticity raises questions for taxonomically important traits: a remarkable new Andean rainfrog (Pristimantis) with the ability to change skin texture. Zool. J. Linnaean Soc. 173:913-928.

h/t: Barry

Readers’ wildlife photographs

March 26, 2015 • 7:55 am

We have a new contributor today, so say hi to Alex MacMillan, who has provided us with a bunch of photos of animals from several taxa, as well as two videos.

I attach 10 of my favourite pics.

Green frog, Lithobates clamitans. Picture taken in Kilally Meadows, London, Ontario. This is a female: the tympanum that covers the ear is about the same diameter as the eye, while in males it is around twice the diameter of the eye.

KONICA MINOLTA DIGITAL CAMERA

Rose-Breasted Grosbeak, Pheucticus ludovicianus. Picture taken in Kilally Meadows, London Ontario. This is a male.

Common Goldeneye, Bucephala clangula. Picture taken on the Thames river in Springbank Park, London Ont. Male bird is caught mid call.

Grey Jay, Perisoreus canadensis. Picture taken Cypress Mountain, British Columbia. The Grey Jay or whiskey jack is a not uncommon bird of the northern and mountain forests. It is very curious and will approach people and readily feed from the hand.

Five-Lined Skink, Plestiodon fasciatus. Picture taked at Rondeau Provincial Park, Ontario. This is a female five-lined skink with her clutch of eggs. It is believed that the females may guard the nest from predators but also help keep them warm by basking in the sun and then going back to the eggs warmed up and transferring some of the heat to the eggs.

Eastern Garter Snake, Thamnophis sirtalis sirtalis. Picture was taken on Pelee Island, Ontario. Many populations of Garter Snakes around the great lakes have a high percentage (sometimes ~50%) of melanistic individuals. This may be because the lake water takes longer to warm up than pond water inland and the dark pigment could help them warm up quicker, though there are other hypotheses including camouflage.

Blue-Winged Warbler, Vermivora cyanoptera. Picture taken at Rondeau P.P., Ont. This is a male Blue-Winged Warbler singing.

Eastern Milk Snake, Lampropeltis triangulum triangulum. Picture taken at Fanshawe Conservation area, London Ont. This is a young milk snake. Apparently people used to think they stole milk from the dairy cows—thus the name.

Snapping Turtle, Chelydra serpentina. Picture taken at Big Creek Marsh near Long Point Ont. This snapping turtle was trying to cross the path while I was hiking Big Creek Marsh.

Spring Peeper, Pseudacris crucifer. Picture taken at Rondeau marsh, Ont. The spring peeper is a commonly heard but rarely seen frog in wetlands of eastern north america.

Here are two videos:

I had just watched this mink attack and kill a squirrel, ran to get my camera and recorded this. You can hear other squirrels scolding it in the background.

Here’s a video that is more audio than visual; it is a night walk in Rondeau Marsh. You can hear woodcock, whip-poor-will, toads, spring peepers and grey tree frogs.

The remarkable spider-tailed viper

February 18, 2015 • 6:57 am

I’ve previously written a post on the spider-tailed viper (Pseudocerastes urarachnoides), a wonderful snake that has a bizarre and deceptively spider-like appendage on its tail. It was discovered in 1968 in Iran, but described as a new species only in 2006, with the authors speculating that the appendage could be used to lure prey. Below is a picture of the snake’s “caudal appendage” taken from the well-named website Life is short, but snakes are long (LISBSAL), which also describes the developmental basis of this structure:

. . . the structure of the [appendage], which is formed of the last pair of subcaudal scales, much enlarged, and a single enlarged dorsal scale. The elongated components are modified lateral scales. X-rays taken by the team showed that the caudal vertebrae extend well into this structure and are not deformed or modified.

So what we have here, as we nearly always do with new structures in evolution, is simply the modification of an old structure in a novel way. One could imagine that mutations that affected the rear scales, making them bigger and more spidery-looking, could give a reproductive advantage (more food!) to the mutant snake. Further mutations would make the lure even more spider-like and more attractive to prey. And perhaps the tail-waving was already in place, though it was surely elaborated after this structure began to evolve.

As I noted in my earlier post, this appendage could function to scare off predators, but the way the snake waves the appendage suggests that it’s a deceptive lure to attract prey who thinks they’re going to eat a juicy spider. Here’s a video of lure-waving:

Further, the informative post on LISBAL on “Spider-tailed adders” gives other information suggesting that this is indeed an evolved trait helping the snake capture prey, particularly birds:

Behavioral observations made in 2008 of a live P. urarachnoides captured in western Iran and maintained in captivity confirm these ideas. Closed-circuit video was used to record behavior, and the results published in the Russian Journal of Herpetology by Behzad Fathinia of Razi University and his colleagues. They observed the snake, a juvenile male that regurgitated a Crested Lark, using its caudal lure to attract sparrows and baby chickens that they introduced into its enclosure. When the birds approached and pecked the tail, the snake struck and envenomated the birds, a process taking less than one half second. A bird was also found in the stomach of the paratype specimen, further evidence that this species might feed heavily on birds in the wild with the aid of its spectacular caudal lure. The tail of P. urarachnoides probably represents the most elaborate morphological caudal ornamentation known in any snake, with the possible exception of the sound-producing rattles of rattlesnakes.

And, indeed, the video below, which came out a year after my first post, shows how the spider “lure” can attract a bird, which is then killed. This video is a bit heavy on rhetoric and light on science, but it still shows the effectiveness of the deceptive tail.

h/t: Mathieu

Readers’ wildlife photos

October 19, 2014 • 11:51 pm

Reader John sends us oodles of photos from The Gambia, and I’ve stuck a lizard (my own photo) in at the bottom:

Having recently returned from NYC, the reported US cases of Ebola has prompted me to try and highlight the indirect impact of the virus on the West Africa country of The Gambia via your Readers’ Photo slot.

Gambia is the smallest country in Africa and despite being surrounded by countries affected by the ravages of the virus, it has remained free from the disease. However, it is now suffering adverse economic impacts because many who normally travel there during its relatively short tourist season, are staying away. This very poor country will find it very difficult with one of its main economic drivers so badly affected. I am in regular contact with friends in Gambia who are confirming their plight.

The Gambia has a terrible history associated with slavery – your older readers will remember Arthur Haley’s Roots story which begins in 1767 when his ancestor, Kunta Kinte, is kidnapped from the banks of the River Gambia at Juffura – and I have met some African Americans visiting to retrace their own ‘roots’.

On a brighter note, it is also known for its fabulous birdlife which makes it a popular destination for many European ‘twitchers’ because of the varied mix of resident African and Euro-Asian migratory species.

The most spectacularly colourful are the iridescent, and aptly named, beautiful sunbirds (Cinnyris pulchella) which appear to occupy the same nectar-eating niche as hummingbirds. The first three photos are of the brighter male with one of the drab female.

Sticking with colourful species, the yellow-crowned gonolek (Laniarius barbarous), red billed fire finch (Lagonosticta senegala) and two species of flycatcher, African paradise (Terpsiphone viridis) and black-headed paradise (Terpsiphone rufiventer), lurk in the rainforests adding bight flashes when they appear.

I have included two owls, Firstly the diminutive (only 6 inches) pearl- spotted owlet (Glaucidium perlatum) and the catlike African Scops Owl (Otus senegalensis)

There are many species of Roller; I have picked the ubiquitous Abyssinian Roller (Coracias abyssinica) and this one hunted the beach outside our hotel.

And of the many Kingfisher species, I include the spectacular Giant (Megaceryle maxima) and the agile hovering Pied (Ceryle rudis)

The last bird is a wader, the Senegal thick-knee (Burhinus senegalensis)

And Professor Ceiling Cat snapped this lizard yesterday at the castle at Vileka Tarnovo, Bulgaria. I have no idea what it is, but ten to one someone will tell me soon.

Four new see-through frogs from Peru

August 27, 2014 • 6:15 am

Have a look at this puppy*; isn’t it gorgeous?

*Yes, I know it’s not a dog, for crying out loud!

It’s a glass frog from Peru, one of four newly-discovered species described in a new paper in Zootaxa by Evan Twomey et al. (reference and link below, but you’ll get only the abstract, and would have to pay big bucks for the paper. Thanks to Evan for sending me the pdf). There’s also a National Geographic blurb which is more accessible than the 87-page monograph, which goes into detail about the frogs’ discovery, description, anatomy, biogeography, phylogeny (based on both nuclear and mitochondrial DNA), “environmental niche models,” their vocalizations and so on. It’s an excellent and comprehensive analysis of this group. And, because I’m a good boy, I went through the whole monograph last night rather than spoon-feeding you what’s in the National Geographic summary. Here are some photos and a few of the authors’ conclusions about the frogs.

Glass frogs are in the family Centrolenidae, which, according to Amphibiaweb, has 151 species in 12 genera. They’re called “glass frogs” because you can see through their bellies, and also through selected parts of their bodies, as we’ll see below. Their transparency reveals their viscera: heart (“pericardium”, the sac containing the heart), liver, and other guts. A weird thing: three of the speices have green bones, a first for frogs!

Twomey et al. summarize the data showing that there are 33 species in Peru, and their paper describes four new ones. Here is one—the same one pictured above. It’s Centrolene charapita, and from the vental aspect you can see into its belly. These pictures and captions are all taken from the paper:

This was found at one location: along a stream in northern Peru. The name of the species comes from the resemblance of the pattern on its back to Aji charapita (peppers); here are some of them, which start of green and turn yellow:

The bottoms of hands and feet of C.charapita. See the bones? They’re green! The authors hypothesize that this color comes from the sequestration of a pigment from bile, biliverdin. Whether or not the green color was simply an accident, or is a result of natural selection (perhaps to aid camouflage) isn’t known.

Voilà, another new species, Chimerella corleone, named after the patriarch of the Godfather movies. It was named because it has a spike sticking out of the upper arm that males may use to fight each other. (The authors clearly have a penchant for colorful species names, which I like.) These are very small frogs: C. corleone, for instance, is only 2 cm long: about 0.8 inch.

Here’s the “type locality” of C. corleone. It would be nice to do field work in such a place!:

Reproduction in species of Chimerella, including C. corleone (a, b, and d; see caption of figure). Males apparently guard the egg masses, which are laid on leaves, and tadpoles, when they hatch, drop into the water:

The third new species, Cochranella guayasamani:

Here are its tadpoles, which also start out transparent but are pink (reasons for the color and transparency unknown). On the right you can see the eggs hatching and the tadpoles dropping off the leaves into the water:

And the fourth new species, Hylinobatrachium anachoretus, the only one found in cloud forest (2050 m). In (b) you can see the ventral view, with the veins, viscera, and heart clearly visible. In (e) you can see a male guarding its clutch; these frogs have parental care. Why are they transparent? Who knows?

Finally, here are ventral views of three species in the genus Hylinobatrachium, showing their transparency. Look at the heart, the veins, and the guts!

These frogs live in relatively inaccessible places, and even in the places where they live they aren’t common. There are many questions about them, including the reasons for their remarkable transparency), but the answers will be hard to come by. How do you figure out why a frog that is so rare is transparent? What kind of experiments can you do?

h/t: Brian

____________

Twomey, E., J. Delia, and S. Castroviejo-Fisher. 2014. A review of Northern Peruvian glassfrogs (Centrolenidae), with the description of four new remarkable species. Zootaxa 3851:1-87.

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