Mossy Frogs: Convergent Crypsis

Alright, sit down, shut up, and let me tell you about some of the coolest frogs in the whole damn world. Someone sent an ask about my favourite example of convergence; this is way up there.

You may have heard of the Vietnamese Mossy Frog, Theloderma corticale, pictured top right in the figure above. This awesome little bastard is now quite common in the pet trade because of how bitching its camouflage makes it look. This is a really fucking awesome example of crypsis, because when these frogs are at rest among moss, they are almost imperceptible.

What makes it so hard to see? Well, for one, it’s fucking green. That’s pretty effective as camouflage when you live on moss. That green isn’t solid though, like a lame-ass Hyla arborea. No, it’s mottled with brown and other shades of green, to break up any solid colours. Next, it has spines all over and around its body, especially on the edges of its limbs. What do these do? They break up the outline of the frog. It doesn’t cast a frog-shaped shadow. This makes it much harder to spot, and is just generally awesome.

But this is Fuck Yeah, Convergent Evolution, not Fuck Yeah, Crypsis! (Yeah that’s a thing now too, I couldn’t help myself).

The green colour and spiny body, often with fringes around the limbs and body, has evolved in many many animals (including my favourites, the Uroplatus geckos).

The evolutionary pressure for this kind of crypsis is so great that incredibly similar structures and body shapes have evolved at least. seven. fucking. times. in at least four families of frogs! There may even be more but I don’t know all of the world’s frog species. These are just the ones I knew of already and a few added by Prof. Karen Lips and Dr. Jodi Rowley (two of the coolest herpetologists on the internet).

In Madagascar alone we have three convergences on this mossy crypsis: some frogs in the genus Spinomantis (Mantellidae:Mantellinae), including S. spinosa depicted above, and the aptly named S. phantasticus; a few frogs in the genus Scaphiophryne (Microhylidae:Scaphiophryninae); and Platypelis grandis (Microhylidae:Cophylinae). These three groups have few things in common, but chief among them is a predilection for moist mossy habitats.

The common ancestor of all seven of these radiations hopped the earth hundreds of millions of years ago. It was barely even a frog, let alone a fucking awesome moss mimic.

The similarity we see in these frogs can therefore mean only one thing: the evolutionary pressures they are experiencing (e.g. being eaten) are selecting for the same solution: bad-ass crypsis. And rather than re-inventing the wheel of crypsis, each group has found the same solution: textured skin to break up the shadow and outline of the body, and mottled green colouration to blend into the foliage.

The convergence is so extreme that you would be forgiven for thinking most of these species to belong to the same genus if you didn’t know they were from completely different sides of the earth.

Convergent evolution is the fucking best.


Scaphiophryne spinosa

Scaphiophryne spinosa is a species of frog in the Microhylidae family. It is endemic to Madagascar. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical swamps, subtropical or tropical moist montane forests, intermittent freshwater marshes, and heavily degraded former forest. It is threatened by habitat loss.
photo source Calphoto Database

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Scaphiophryne marmorata by Stephen Zozaya

Plurals and Possessives in Taxonomic Nomenclature

Okay this is a serious problem, and people need to listen up.

It is very easy:

  • A species has one name.
  • Only one name.
  • That name is not altered in any way.
  • The spelling on that name is not open to interpretation.
  • It cannot be pluralised. No -s, no -es, no -i, no nothing.
  • You do not alter its declension ever for any reason.
  • The gender of the specific epithet depends on the gender of the genus (if the specific epithet is a Latinized word). It must change if the species is moved to another genus of different gender, but not for any other reason.
  • Genera and species CANNOT be made possessive: Anubias’, Scaphiophryne gottlebei’s, etc. ARE WRONG.
  • All taxonomic names can be used as a singular or plural form. Usually singular is preferred.

Here is how you conjugate Anubias, the aquatic plant genus:

  • 1 Anubias plant
  • 100 Anubias plants
  • 1014Anubias plants
  • You could equally say 1 Anubias and 100 Anubias, but it would be less clear.

Here is how not to conjugate Anubias:

  • An Anubia
  • 100 Anubia
  • A bajillion Anubiases

Apparently some people like to call a single Betta a Betta splendenNO.

Betta splendens is always Betta splendens irrespective of how many B. splendens you might be talking about. Taking out the s at the end violates its binomial name and is WRONG.

This rule is true for all genera and species.

Thanks to fishmostly for bringing this up in an ask. I hope this clears it up.