Dr Mark D. Scherz

@markscherz

Curator of Herpetology & Associate Professor of Vertebrate Zoology at Natural History Museum of Denmark • ERC StG: GEMINI • Co-host of SquaMates Podcast and AnatomyInsights on Youtube • He/Him

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Bluesky

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Dr Mark D. Scherz@markscherz· 16d

Now meet the six other #NewSpecies we described alongside R. quentini!! 🧪🐸

Dr Mark D. Scherz@markscherz· 17d

Say hello to Quentin’s Diamond Frog, Rhombophryne quentini. 🧪🐸 #NewSpecies

Dr Mark D. Scherz@markscherz· 21d

This little pebble is Rhombophryne kilonjy, a small, poorly known and obscure species related to R. ellae and R. quentini but found in lowland forest close to the coast in northwestern Madagascar. The name kilonjy means ‘pebble’ in Malagasy because, well, just look at it. 🧪🐸 📸 F. Andreone

A pebble of a frog. It is round. It is pale beige. It has a smoky grey chevron on the back and a distinct curved fold of skin over the ear. It rests on a pile of leaves. There is almost a feeling that, hefted in the right way, it would skip well across a calm little lake. Please do not skip the frog.

Dr Mark D. Scherz@markscherz· 21d

Rhombophryne quentini is an orange-thighed species from high-elevation in northern Madagascar. In 2020 I named the closely related R. ellae after my partner, Ella—so I took particularly great pleasure in naming this new species after our son, Quentin. A little family of frogs. 🧪🐸 📸 M. Vences

A rather chubby brown frog on a moss-covered log. It's not much to look at. But just wait.

Hidden on those thighs of that bland brown frog were spots of bright orange, perhaps even red, and large black spots on the hips outlined with cream. It gives a very different picture of the animal! Here seen from behind, the left leg stretched slightly down to reveal the full redness of the posterior thigh.

Dr Mark D. Scherz@markscherz· 21d

Rhombophryne kotrobaratra is a species from northeastern Madagascar with unusually long and strong hindlimbs. The name kotrobaratra means ‘thunder and lightning’ in Malagasy, and refers to the inclement weather that seems to bring these frogs out (true for all Rhombophryne, really). 🧪🐸 📸 F. Andreone

To the untrained eye, this might be called a 'toad'; its resemblance to a bufonid is striking, with rough skin with distinct warts and bumps. But this is not a bufonid. It lacks the parotid glands. It has strong hindlimbs. The back is brown splotched with dark umber, especially in a chevron over the shoulders. The eye is almost maroon as the frog looks to frame left. It rests on a large dead leaf on the forest floor.

Dr Mark D. Scherz@markscherz· 21d

Rhombophryne anatiala is a very poorly known species very closely related to R. sonaliae but found further north and differing subtly. The name anatiala means ‘in the forest’ in Malagasy, referring to the forest habitat of these frogs. 🧪🐸 📸 F. Andreone

Picture a slightly overdone American-style pancake. Add frog limbs along the edges. There you go.

Dr Mark D. Scherz@markscherz· 21d

Rhombophryne sonaliae is a rather well known species from eastern Madagascar that's previously been called R. alluaudi—until we showed in 2019 that the name belonged in fact to a species of Plethodontohyla from southern Madagascar! We dedicated this species to our esteemed colleague Sonali Garg. 🧪🐸

A very, very shiny frog, reflecting the diffuser used to take the picture. Its skin glistens, but below the shine is a fine grey-brown. In the hip and on the thigh are large, yellow spots reminiscent of the egg spots of cichlid fish. These are totally hidden when the frog is at rest; here it is just starting a step forward.

Dr Mark D. Scherz@markscherz· 21d

Rhombophryne mavokely is a wee species from the northeast. Mavokely is Malagasy for ‘pink’ but literally translates as ‘small yellow’ (mavo = yellow, kely = small). I LOVE this. As they're small, sometimes pink and sometimes yellowish, the name seemed apt. This one is for @gretchenmcculloch.com 🧪🐸

A pinkish, almost peach rotund frog on a green leaf. Its back has a few black spots with light centres. Above the ear is a dark blotch, behind the richly bronze eyes.

Dr Mark D. Scherz@markscherz· 21d

But I want to introduce BlueSky to the seven new species in turn. Let's start with Rhombophryne maraorao. This is a burrowing species from the northeast of Madagascar. The name maraorao means ‘rough to the touch’ in Malagasy, referring to the rough skin of this species. 🧪🐸 📸 F. Andreone

Basically an animated pinecone on a log. This frog looks like a clump of mud, not a frog.

Dr Mark D. Scherz@markscherz· 21d

I am thrilled to introduce seven new species of diamond frogs from Madagascar! A new monograph on the genus Rhombophryne published #OpenAccess in Vertebrate Zoology. 🧪🐸 doi.org/10.3897/vz.7...

A new species, Rhombophryne sonaliae, looking right at you. It looks a lot like Kaloula pulchra, aka chubby frogs, with its light flank stripes and dark brown top and sides, but is super shiny.

Dr Mark D. Scherz@markscherz· Jul 13

Glorious to be able to watch @criticalrole.bsky.social with Edinburgh Castle as a backdrop!

Full stands in front of a brightly lit stage, itself in front of Edinburgh castle with sconces lit, in the evening light.

Dr Mark D. Scherz@markscherz· Jul 5

‘Playground’ time with an animal kid

A child prone on the sand, his hands full of beetles, the swings and other accoutrements of the playground forlorn and forgotten in the background.

Dr Mark D. Scherz@markscherz· Jul 2

Can I offer a fresh one?

Dr Mark D. Scherz@markscherz· Jun 30

Yesterday I presented what I think was the first conference poster of my career 😅 at #SMBE2026, talking about my ERC StG project on the genomics of miniaturisation in vertebrates—GEMINI. Really happy for the discussions it sparked. Thanks everyone who stopped by! 🧪

A selfie of Mark standing beside his poster, which features a penguin trying to explain what miniaturisation is and why it matters.

Dr Mark D. Scherz@markscherz· Jun 3

A hilarious effect of the way @inaturalist.bsky.social obscures data on threatened species is that observations that are all from more or less the same place form square clouds of obscured points. Here, the observations of the giant chameleon Calumma parsonii around Andasibe in eastern Madagascar 🧪🦎

A map of rainforest in Eastern Madagascar, with a beautiful square point cloud representing observations around Andasibe.

Dr Mark D. Scherz@markscherz· May 27

I have had a great many frustrations in 3D printing recently, but the last few prints have been absolutely beautiful. It’s honestly hard to believe we even have this technology.

A dragon wing in pale white resin on the cerulean printing plate of a Photon S 3D printer

Dr Mark D. Scherz@markscherz· May 21

Or this

Dr Mark D. Scherz@markscherz· May 18

Today I caught one of the largest frogs of my life. This gigantic Pelophylax ridibundus belongs to a Balkan lineage (formerly P. kurtmuelleri) that has an established introduced population in one lake in central Copenhagen. They are about twice the size of our native green frogs! 🐸🧪

Yours truly and the Very Large Frog, our faces with the same expression. The Frog (the F is capitalised; a proper noun for a proper Frog) is huge, about the size of my face, and held in a gloved hand.

Dr Mark D. Scherz@markscherz· May 7

Denmark may not have a huge amphibian diversity, but some of our frogs are real stunners. Just look at this handsome green toad, Bufotes viridis!

Picture if you will a light brown, almost beige toad. Cover that toad in large algal-green blotches, and intersperse a few warts that are neither green nor tan, but rather a rich orange. For an artistic flare, this same colour is repeated at the tips of the fingers and toes. The eye is black flecked with gold, with golden rims outlining the iris on top and below. A masterpiece of amphibian art.

Dr Mark D. Scherz@markscherz· May 7

Spring in the north means tadpoles in our lakes and ponds! These little common toad tadpoles are in one of the little ponds at the Botanical Garden here in Copenhagen (part of @nhmdk.bsky.social), which is also full of newts in full breeding dress. 😍

A wide angle photo of a pond reflecting a cloud spotted sky, with little black toad poles in the shallows in the foreground

Dr Mark D. Scherz@markscherz· Apr 13

Three weeks after being in the rainforest of Madagascar, I spent the day surveying reptiles and amphibians in Denmark. Somewhat different weather. But still very rewarding. We saw a whopping NINETEEN adders! 🐍🧪

A large female adder, curled in a defensive posture among leaf litter, sticks, and rocks.

Dr Mark D. Scherz@markscherz· Mar 31

Something parasitic definitely got this robberfly I found stuck to this leaf in littoral forest of southeastern Madagascar. But what kind of parasite? Fungal? Vespid? Any ideas? 🧪🪰

A weird bulbous expansion stretches up from the back of thorax of a robber fly, which has somehow gotten attached to the tip of a leaf in the forest.

Dr Mark D. Scherz@markscherz· Mar 3

Yesterday we hiked out of the forest after five days totally off-grid. Hard to believe what’s happened in the world in the last five days! I’m quite glad we were out of signal range and able to focus on just excellent frogs and reptiles. 🧪🐸🦎🐍🇲🇬

Boophis reticulatus, a brown tree frog with weird ridges on its back, perched on a serrated bright green Pandanus leaf.

Platypelis pollicaris, a little brown narrow-mouth frog with flecks of gold over its body, sitting atop a bright green leaf

A female Calumma oshaughnessyi, a large green and grey chameleon with diagonal stripes up its body, walking along a branch toward camera left.

A portrait of Liopholidophis dolicocercus (sorry if you’re using a system that reads these Latin names aloud!), a black, brown, and bright yellow snake. In my years working with snakes in Madagascar, I think I have never had a more cooperative subject. It was totally calm and posable!

Dr Mark D. Scherz@markscherz· Feb 25

Platypelis tuberifera always remind me of a rockclimber bridging a chimney, the way they sit in the groove of Pandanus fronds. Such charming frogs! And we know so very little about their ecology. For instance, as far as I know nobody has ever found their eggs or tadpoles! 🧪🐸🇲🇬

A little yellow and brown frog in the groove in the middle of a vibrant green Pandanus frond, its feet splayed to the side to brace it in place.

Dr Mark D. Scherz@markscherz· Feb 24

Boophis albilabris is one of Madagascar’s largest tree frogs. Today we found this individual just beside the road near Ranomafana National Park. 🐸🧪

A big brown tree frog on a rich green leaf. The flank of the frog is marbled with yellow, its toe webbing is orange, its thigh striped with dark brown, the edge of its eye bright green, and the edge of the lip bright yellow. It sounds gaudy, but really it’s quite subtle.

Dr Mark D. Scherz@markscherz· Feb 22

Our main target species in this area was Mini mum, one of the smallest frogs in the world. Every morning, from at least 5 to 10, the air was full of their tiny peeping calls. Finding one is hard, despite incredible population density, because they live in the spaces between the leaf litter. 🇲🇬🐸🧪

A very small frog in the leaf litter. This is Mini mum. The name says it all: these frogs are approaching what we think is the minimum possible adult body size for a vertebrate.

Dr Mark D. Scherz@markscherz· Feb 22

But WHAT a forest! Dry littoral forest on sandy soil going down into shallow valleys full of these incredible swamps dominated by Pandanus and Ravenala. Choruses of different species of frogs take turns singing throughout the day and night. It’s a special place. 🧪🇲🇬🐸🌴

A swamp with dark brown water, full of pandanus screw palms rising up to and above eye height. We had to wade to the knee through this water, leaving our shoes and socks soaked for the rest of the hike.

Dry littoral forest on the hills above the swamps. Still very humid - 80-90% - but there’s almost no moisture in the soil as it’s all just basically sand. It feels like this forest just shouldn’t exist. So weird. And so many orchids!!

Dr Mark D. Scherz@markscherz· Feb 22

Fortunately the route was not a long one; the porters can make it in an hour or so. It took us about 90 minutes. But a good deal of that is in the scorching heat; we were sweating buckets today. 🧪🐸🇲🇬

Dr Mark D. Scherz@markscherz· Feb 22

It took 21 porters to bring the materials for this team of eight to live and work for five days inside the forest. 19 to get us back out again today. They were awesome, some carrying very fragile or cumbersome loads through deep mud and swamp 🧪🇲🇬🐸

The team with all 21 porters who helped get us into the forest, and also a chicken.

Dr Mark D. Scherz@markscherz· Feb 22

Here’s a photo of the awesome team I’ve been working with in Agnalazaha. Wonderful, extremely hard-working people. Such a privilege to be in this unique ecosystem with such a dedicated group! 🧪🇲🇬🐸