How a 162-Year-Old Specimen Helped Prove the Existence of an ‘Incredulous’ Lizard Species

A serendipitous find in the National Museum of Natural History’s collections yielded just the second known specimen of a mysterious Cuban anole

The vast majority of the more than 148 million specimens and objects in the National Museum of Natural History’s collections are off display. But everything — whether it be a moth, meteorite, moss or mammoth — tells a story that helps museum researchers make sense of the natural world. Each month, the Specimen Spotlight series will highlight a different specimen or object from the world’s largest natural history collection to shed light on why we collect.

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When American botanist Charles Wright collected what was to become USNM 5095, it was just another lizard. It was 1861 and Wright had already traveled everywhere from South Africa to the Bering Sea, documenting thousands of plants — and anything else he came across — along the way. So, when he noticed a three-inch-long green anole in the remote forests of southeastern Cuba, he merely scooped up the lizard for another expert to identify sometime later.

Wright probably did not think that identifying this lizard would take 162 years. And he would never have suspected that the seemingly nondescript reptile he collected would confirm the existence of a species so enigmatic that even its scientific name reflects an aura of mystery.

The case was finally put to rest in 2023 when scientists at the National Museum of Natural History identified Wright’s discovery as just the second known specimen of Anolis incredulus.

This solved an identity crisis that had long lingered in the lizard community. Wright’s specimen had avoided recognition for decades thanks to a long history of misidentification. When the Smithsonian Institution first catalogued the lizard on February 1, 1861, curators couldn’t pin it down to a species. Instead, they designated it only by its genus, Anolis. The curators then labeled the specimen (and several other anoles that Wright collected in Cuba) number 5095 and preserved it in a jar of alcohol.

Over the years, herpetologists determined that many of the anoles collected by Wright represented Anolis porcatus, a species found widely across the island. However, one individual was more confusing, receiving multiple monikers as experts identified and re-identified the specimen. Eventually, this enigmatic specimen, which came to be known as USNM 5095 (for United States National Museum, the name then shared by all of the Smithsonian’s research divisions), was determined to be an Anolis guazuma and preserved accordingly.

For years, the specimen resided among A. guazuma specimens, blending in amidst its strange jar-fellows. But that all changed when Esther Langan, the collection manager in the museum’s division of amphibians and reptiles, came across USNM 5095 while gathering Anolis guazuma specimens for another herpetologist’s research project.

Langan noticed that USNM 5095 seemed to have a broader head than did its neighbors, so she snapped a picture and sent it to herpetologist Kevin de Queiroz, one of the museum’s curators of amphibians and reptiles. de Queiroz agreed that it looked odd, further noting that while its neighbors were stick-thin and had brown scales, USNM 5095 had a stockier build and faint greenish tint, faded after soaking in alcohol for more than a century. He suspected a misplacement.

If anyone could identify USNM 5095, it would be de Queiroz. He has spent over forty years studying anoles and similar lizards from across the Americas. But this specimen left him perplexed. “I've been to that part of Cuba, and I know the anole fauna moderately well, but it didn't immediately jump out to me what this was,” said de Queiroz. “It wasn’t Anolis guazuma. But what was it?”

de Queiroz reviewed the local species, but none of them seemed to line up with USNM 5095’s peculiar set of features. Intrigued, he dug deeper into the scientific literature on anoles. That’s when he came across a study published 1998 in a Spanish-Cuban scientific journal. That paper proposed that a small green anole collected in remote southeastern Cuba should be considered its own species.

But making the case for the new anole species had proven difficult. Nobody had seen a living specimen since 1963. What’s more, the anole was collected by an entomologist who likely did not know the best techniques of documenting and preserving reptiles, so the specimen was in subpar condition and had little accompanying information. Anticipating skepticism, the herpetologists describing the new species dubbed it Anolis incredulus, a name meant to both acknowledge the uncertainty of the lizard’s status and encourage other scientists to search for more individuals.

More than twenty years later, the proposed species had faded into obscurity. “It was off most people's radars,” de Queiroz said. “Unless you were looking at small anoles from eastern Cuba, you probably wouldn't know about it.” Even de Queiroz, one of the world’s foremost experts on anoles, was not sure he had heard of Anolis incredulus, and the species was not included in a paper he coauthored on the evolutionary history of all anole species. But now, the odd lizard specimen in front of him demanded a closer look.

de Queiroz knew that identifying Wright’s reptile once and for all would require painstaking measurements and observations. There are 66 known species of anoles in Cuba, many of which are very similar to one another. To distinguish them, herpetologists can rarely point to one distinctive feature. Instead, they have to rely on deductive reasoning and careful analysis of several characteristics. de Queiroz got to work, closely inspecting the shape and size of USNM 5095’s scales and even reconstructing a 3D model of the specimen’s skeleton with CT scans.

At every turn, de Queiroz’s measurements confirmed his initial suspicions: USNM 5095 couldn’t be a member of any of the better-known Cuban anole species. And almost everything aligned with the single known specimen of Anolis incredulus. By the time de Queiroz had examined the specimen from snout to tail, there was little doubt: Charles Wright’s lizard and the widely doubted Anolis incredulus were one and the same species. The incredulous anole was now scientifically credible.

Based on USNM 5095’s morphology, de Queiroz and former Natural History Research Experiences intern Jonathan Huie were able to make some basic inferences about the ecology of Anolis incredulus. For instance, they deduced from its body proportions that the lizards primarily live on twigs. Their green scales might be used to sneak up on tasty insects perched on green stems or fern fronds. Everything beyond that is still in question. With no observations of the living lizards, most aspects of their ecology and behavior remain unknown.

de Queiroz hopes that Cuban herpetologists will someday return to the island’s southeastern mountains to give Anolis incredulus the in-depth study that it deserves. Along the way, they might even discover something else new. “That area is still under-explored,” de Queiroz said. “Most of the new species of Cuban anoles discovered in the last 30 years have come from that area.”

In the meantime, de Queiroz may be just as likely to come across an unrecognized species in the museum’s collections — something he’s done several times throughout his career. “I still get a kick out of it,” he said. “It’s fun to find something new.” And while not all of those finds came with a 162-year-long backstory, in the largest natural history collection in the world, there’s always something in need of a closer look.

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Benjamin Hack | Read More

Benjamin Hack is Science Writing Intern at the Smithsonian National Museum of Natural History. He covers anything and everything related to the natural world for Smithsonian Voices, the museum’s blog. Ever fascinated by ecology, Ben studied and conducted research in biology as an undergraduate at Cornell before transitioning into science communication. His work, which has appeared in magazines such as Audubon and Living Bird, highlights both the joy of nature and the dire challenges facing the world’s biodiversity. In his spare time, Ben can often be found outside birdwatching.