February 16, 2012 • 10:52 am

Speaking of newly found herps, an article by Frank Glow et al. in the latest PLoS One describes what may be the world’s smallest reptiles—indeed, among the world’s smallest amniotes.  They’re four species of leaf chameleons in the genus Brookesia from northern Madagascar.  Here they are, and note that the scale bar is 5 mm—about 0.2 inch! These are adults, and B. micra adults are about 15-27 mm long: about 0.6-1 inch long!  That’s a small lizard!

Here’s a baby on a matchstick from the BBC website, which gives more information but doesn’t identify the species.  Cute, eh?

And, as is often the case in animals, the diagnostic traits involve the shape of male genitalia, perhaps because those genitals evolve rapidly by sexual selection:

“In general, the hemipenes found in the B. minima group are remarkably dissimilar among species.”

Here’s a figure of the hemipenes (the bifurcated penis of many reptiles):

The photos show for each species, a general view of the organs and a close-up. For B. desperata, the inset picture shows a non-turgid everted hemipenis where the two apex projections are very prominent. Note that also several other of the shown preparations are not fully turgid, especially in B. ramanantsoai and B. micra. In two other species (B. confidens and B. tristis) the shown hemipenes might not be fully everted.

In other news, the Torygraph has reported that goats can develop different accents when moved to new social groups, so that their bleats come to resemble that of their companions, a form of cultural “inheritance”. There also appears to be a genetic component to among-family differences in bleats.  I haven’t read the paper, which was published in Animal Behaviour.

Finally, Larry, the official Chief Mouser to the Cabinet Office at 10 Downing Street (a rescue cat), has celebrated his first year in residence with a party. Details and photos are at the Prime Minister’s official website.

h/t: David and a couple of others whose emails I’ve lost.

15 thoughts on “Marginalia

  1. Very cool discoveries indeed but one small correction: hemipenes is plural for hemipenis, some of which are bifurcated (many snakes) and some which are not–in those images of the tiny chameleons BOTH hemipenes are everted, tho they might look like a single bifurcated organ.

  2. Larry is the typical mixed breed alley cat, a healthy, epitome of a feline if I ever saw one. His markings exhibit his extensive mixed genetics. More beautiful to me than pure breeds.

  3. “three cheers for your willy or john thomas, hooray for your one-eyed trouser snake…” Darren Naish at Tetropod Zoology had a great post about terrifying turtle sex organs a few months ago that’s worth a look too, if you’re into that kind of thing.

  4. I just notice that if I scroll my window up and down while looking at the image at the top of this post, the tails wag. Yet another reason for someone to bring drinks!

  5. One of my proudest moments on a Madagascar field trip back in the 90s was finding one of these Brookesia all by myself. Even the larger species are extremely small and cryptic, and the first person to see any that were there was almost always the local guide.

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