Frog with a leopard pattern?
Sri Lanka’s amphibian fauna is known for its extraordinary diversity and high level of endemism. The genus Pseudophilautus in particular, which includes many directly developing frog species, has diversified strongly in the island’s isolated forest areas. Pseudophilautus pardus was scientifically described in 2007, based on a single specimen collected in the 19th century. This species was distinguished above all by its spotted coloration, which seemed to set it apart from other members of the genus. Because no new finds were made during later surveys, the species was classified as extinct.
The frog species Pseudophilautus pardus, endemic to Sri Lanka and considered extinct, received its name because of its striking pattern. The species name “pardus” is derived from the Greek word for leopard. P. pardus was supposed to stand out clearly from other species of the genus Pseudophilautus through its leopard-like spotted pattern and coloration.
Many species of the family of shrub frogs (Rhacophoridae) native to Sri Lanka are already considered extinct, including Pseudophilautus temporalis, Pseudophilautus adspersus and Pseudophilautus maia. P. pardus was also listed as extinct by the International Union for Conservation of Nature (IUCN), since no specimen had been seen for more than 100 years. Despite intensive searches in recent decades, there was no evidence at all of this species, and its exact habitat remained unknown. As with other frogs of this genus, the assumed cause of the species’ extinction was the loss of natural habitat. Pseudophilautus frogs are known to live in trees.
Pseudophilautus pardus – fact sheet
| alternative name | Leopard bubble-nest frog |
| scientific names | Pseudophilautus viridis, Pseudophilautus pardus, Philautus pardus |
| original distribution area | Sri Lanka |
| time of extinction | 1859 at the earliest – rediscovered in 2023 or synonymized with P. viridis |
| causes of extinction | unclear, possibly habitat loss |
| IUCN status | extinct |
Only a single specimen
P. pardus was known only from a single adult female specimen collected before 1859. The holotype measured 3.2 centimeters. In preservative fluid, its underside was pale yellow, while the upper side appeared yellow-brown with dark brown spots.
As with other frogs of the genus, it is assumed that P. pardus laid its eggs on the forest floor, where they developed directly into small frogs without passing through a larval stage as tadpoles. This requires a humid climate, since dry periods could harm the sensitive eggs.
(© Rohitjahnavi, CC BY-SA 4.0, via Wikimedia Commons)
New findings: P. pardus is not a distinct species
In 2013, a frog was discovered in the Samanala Nature Reserve that externally resembled the historical holotype of Pseudophilautus pardus. A comprehensive genetic, morphological and geographical analysis of this specimen led in 2023 to a reassessment of the taxonomic status of P. pardus.
A genetic analysis of the specimen found in 2013 showed only minimal differences (0.77 to 0.96 %) from the genome of Pseudophilautus viridis, another frog species that also occurs in the central hills of Sri Lanka. Such small deviations are below the threshold usually used to delimit species. Supplementary investigations of morphological characters confirmed the genetic findings: Except for the striking spotted pattern, the physical characteristics of the two species match.
Morphological analyses additionally confirmed these results. The frog found in 2013 was compared with 14 individuals of P. viridis and with the holotype of P. pardus. Except for the spotted coloration, all specimens showed complete overlap in their characters. These included the angles of the snout, the absence of vomerine teeth and lingual papillae, and measurements such as head width, leg length and eye diameter.
The study also documented considerable color variability within the population of P. viridis. While most individuals had a uniform green coloration, brown, yellowish and spotted variants also occurred. The characteristic spots of P. pardus, once regarded as a diagnostic feature, are therefore a rare but natural color variation within P. viridis.
P. pardus as a synonym of P. viridis
The genetic and morphological results led to the conclusion that Pseudophilautus pardus is not an independent taxon, but must be regarded as a junior synonym of Pseudophilautus viridis. This means that the frog species once classified as extinct does not exist—the specimen on which P. pardus was described belongs to the still-living species P. viridis. This reassessment shows how important modern methods of genetic analysis and taxonomy are for the correct documentation of biodiversity.
About the author: Doreen Fräßdorf
Doreen Fräßdorf is the author and publisher of artensterben.de. She researches and writes about extinct and endangered species in the modern era, with a focus on red lists, scientific studies, historical sources, and current conservation efforts. The goal is a clear, evidence-based overview of biodiversity loss and species protection.
She is also the author of a non-fiction book about extinct modern-era mammals.
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