Fossils of global importance discovered in Rizal
Scientists from the Philippines, the Czech Republic, and Taiwan have made major discoveries in global paleontological studies through fish fossils of the Pleistocene period collected a decade ago at a housing project site in Antipolo, Rizal.
Paleontology is a branch of science dealing with fossilized plants and animals, while Pleistocene is the name of the geological epoch dating back 2.58 million to 11,700 years ago.
The Antipolo fossils are the first-ever discovery of freshwater fish fossils belonging to a particular taxonomic (scientific classification of organisms) group in the Western Pacific.
Part of the said fossils recovered in what is now a subdivision in Barangay Dela Paz is the first record of a swamp eel (Synbranchidae) fossil in the world.
The general area where these were found is what scientists call the Laguna Formation, formed largely due to past volcanic activities. These species lived in a freshwater lake environment similar to what is now Taal Lake in Batangas province.
Landmark study
The study was conducted by Abigael Castro and Jaan Nogot of the Geology and Paleontology Division of the National Museum; Tomáš Přikryl of the Czech Academy of Sciences; Allan Gil Fernando, Clarence Magtoto, and Dominique Mediodia of the University of the Philippines; Kevin Garas of the Mines and Geosciences Bureau; and Chien-Hsiang Lin of Taiwan’s Academia Sinica.
It was recently published in the Swiss Journal of Paleontology as an open-access article, free for everyone to read.
This landmark study, according to the aforementioned researchers, “represents the first systematic study of freshwater fish fossils in the Philippines and provides valuable data that can be used to compare with modern ecosystems.”
The results, they said, “improve our understanding of the biodiversity and evolutionary history of Southeast Asia’s freshwater ecosystems.”
Their study puts forward the fact that the Philippines has a rich freshwater biodiversity, although they note that its evolutionary history and distribution is largely unexplored.
The specimens include 10 individuals, the biggest measuring less than 70 millimeters, belonging to three fish families: Dorosomatidae, Gobiidae, and Synbranchidae.
Well-preserved
The first type is related to sardines like the tawilis (Sardinella tawilis) of Lake Taal, while the second type is made up small ray-finned fishes, and the third type of swamp eels.
The researchers noted that the possibility of these belonging to a separate species is not ruled out. They also said the discovery of the swamp eel fossils “suggests an Indo-Pacific origin for the genus during the Pleistocene and started its expansion to Southeast Asia, northern Australia, West Africa, and Middle America.”
Comparing the fossils to other similar fossils in Japan, China, Taiwan, and Indonesia, they said the Philippine samples are exceptional as these are well-preserved and provided defined classification.
“The discovery of this well-preserved freshwater fish fossil assemblage in the Philippines not only suggests a different paleoenvironmental condition but, more importantly, it uncovers an extraordinary paleodiversity that has not been previously reported from the region,” they said.
“Our findings pave the way for promising scientific exploration and further understanding of the region’s paleodiversity,” they concluded.
Apart from these identified species, other fossils noted and recovered in the area include those of other fishes, frogs, and mollusks as well as leaf imprints and plant remains.
