Clusia nanophylla Named Critically Endangered in Panama

Scientists have identified a tree growing on a single Panamanian mountainside as a new species and assessed it as Critically Endangered.

Its discovery and apparent decline occurred in such quick succession that the species seems to have been vanishing before scientists could officially document it.

Discovery on a lone mountainside

Plant specimens gathered on Cerro Colorado in western Panama, almost 25 years apart, repeatedly indicated the presence of an unrecognised tree.

Jorge Aranda of the Smithsonian Tropical Research Institute (STRI) spotted the previously undescribed species while examining the collections.

When Aranda and his colleagues revisited the area to obtain further material, they found a population considerably sparser than the original specimens had implied.

What began as the formal naming of a plant therefore became a conservation concern almost immediately.

Unique clues in leaves and fruit

The tree’s diminutive size was a key distinguishing feature: its leaves are only around 1.0 to 3.8 cm long.

In comparison with closely related species, it has fewer pollen-producing structures in its flowers and differently shaped fruit.

The formal publication records that Clusia nanophylla was described on 6 December 2025; its name refers to its exceptionally small leaves.

Establishing the correct identity mattered beyond herbarium collections, since a formal name enables inclusion in databases and maps, as well as legal consideration.

A crowded Clusia genus in the forest

Throughout tropical America, Clusia comprises roughly 314 species, occupying habitats ranging from wet lowlands to montane forests.

In Panama, this variety may be concentrated within forest stretches of just 9 to 20 metres, making similar-looking plants difficult to tell apart.

The densely packed Panamanian lineages help explain why a plant with only subtle differences could remain in collections for years without receiving a name.

Panama itself has at least 42 Clusia species, meaning that distinguishing another required close comparison.

Seeds that are dispersed by birds

Unlike many tropical trees, Clusia species have shiny leaves and fruit that split open to reveal orange arils, the fleshy coverings around their seeds.

Birds consume these seed packages and carry them away from the parent tree, providing the genus with a means of dispersal.

Yet seed movement cannot rescue a species if its sole known location is contracting more quickly than seedlings can become established.

This seed ecology makes the loss especially serious, as the disappearance of one small population could remove an entire part of local diversity.

Exhalation under the cover of night

Researchers are also interested in Clusia because of CAM, a photosynthetic pathway through which some plants absorb carbon dioxide at night.

By opening their pores after nightfall, these plants lose less water and can continue producing sugars as conditions become drier.

A whole-canopy study involving other Clusia trees found that certain species can shift between daytime and night-time carbon capture as water stress increases.

Rapid collapse of safe habitats

Clusia nanophylla is currently known from just one mountainous area between Hato Chamí and Hato Ratón in western Panama.

Road construction and the expansion of pasture are encroaching on this habitat, reducing the forest cover on which the tree depends.

The researchers calculated its occupied area at approximately 12 km², while its range is about 4,174 km².

These figures help account for the paper’s provisional assessment of the tree as Critically Endangered, indicating an extremely high risk of extinction.

Significance of the research

A plant without a formal name can be overlooked by systems used to monitor biodiversity, land use and conservation planning.

After taxonomists describe a species, it can appear on checklists, be compared with specimens in other collections and be highlighted during policy reviews.

“It’s an arduous process, and it takes a lot of time, from collecting samples with all the plant parts, such as the flowers and fruit, measuring everything and describing every aspect of the plant,” said Aranda.

The process of naming becomes particularly pressing when a tree may disappear before scientists have completed its description.

Answers in herbarium shelves

Herbarium collections proved vital in this case, as older STRI specimens allowed researchers to compare flowering branches, fruit and leaves gathered over many years.

Records held in the STRI herbarium can show that a specimen carrying a familiar label is actually an unseen species.

They also retain the evidence required when later botanists return to a location and investigate what has changed.

For nations with abundant plant life but insufficient specialists, this documentary record may determine whether a species is recognised or lost.

Racing against habitat loss

The species now depends on land-use decisions affecting one small mountain population.

Local protections could reduce forest clearance, but only if authorities and communities regard the tree as part of the forest’s wider value.

“However, the more plants we identify and add to the collections, the better we can understand the true breadth of the plant biodiversity in the country,” said Aranda.

Viewed as a whole, Clusia nanophylla is both a botanical discovery and a warning about species that remain unnoticed.

The tree’s story brings together naming, ecology and conservation in a single progression: locate the species, demonstrate that it is distinct, then fight for time.

Panama is likely to contain more plants like this one, but this example demonstrates that discovery by itself does not guarantee survival.