What does a submerged Philippines look like? Newly discovered gastropod fossil could hold answers

MANILA, Philippines — The newly discovered fossil gastropods in Masungi Georeserve could hold answers to what life was like when major landmasses in the Philippines were submerged deep underwater, according to researchers. 

Potentially the “first and oldest” fossil record of its kind in the country, this new discovery by geologists and paleontologists from the University of the Philippines could help them reconstruct the country’s rich geological history and underwater landscape 60 million years ago, Associate Professor Allan Gil Fernando told Philstar.com. 

Fernando said that studying the ancient gastropods may allow researchers to learn what species existed in the past and understand “how the Philippines developed into the biodiverse country it is today.”

The discovery was made by Fernando and Alyssa Peleo-Alampay, Leopoldo de Silva, Jr., and Joaquin Miguel Lacson. 

Gastropods, which have appeared often in archaeological deposits, are a class of mollusks that include snails, slugs (snails with no shells) and limpets. They have thrived across all three primary habitats: the ocean, freshwater environments and land.

‘Underwater' world

Posted to chart a new history of how the Masungi landscape was submerged underwater 60 million years ago, the fossil gastropods have been potentially hiding in plain sight all along, Fernando told Philstar.com.

Researchers from UP’s National Institute of Geological Sciences were sampling exposed limestones in Masungi in July when they stumbled upon the fossil gastropods sitting just “a few meters away from a trail that guests use to go around the park.”

“The fossils have been there the whole time, probably seen by the guides and the visitors, not fully aware of the significance of the fossils,” Fernando said.

Fernando explained that their fieldwork involved the detailed observation of the limestone formations in Masungi and the fossils contained within it “to determine the age and the paleoenvironment where the limestones were formed.” 

Fossils found in limestones, including gastropods, corals, bivalves, echinoids, and foraminifera, play a crucial role in reconstructing the paleoenvironment and dating the limestone.

“So, the next time you see a limestone, imagine that these rocks used to be underwater and was once teeming with life which are the fossils that you now see embedded in the rocks,” Fernando added.

Fernando said that their team did not realize the significance of the fossil until they consulted a Japanese colleague who specialized in fossil mollusks.

“We will not be disclosing yet what specific type of gastropod was discovered in Masungi until the study is completed, but once it is verified, yes, this will be indeed the first and oldest record of its kind in the Philippines,” he said. 

Other areas where this type of gastropod has been discovered are North America, Africa, Europe and Asia. 

“In Southeast Asia, they were previously collected only in Indonesia. The rocks where the fossils were collected are Eocene in age,” Fernando added.

He said that the discovery suggests that “there are still a lot of things that need to be studied in the Philippines.” 

“The fossils provide information about the past and this is important in understanding the geological history of the country,” Fernando added.

His team is set to conduct a follow-up fieldwork later this year to collect more samples and study the fossils in detail. 

They also plan to create and display informative posters and tarpaulins along the Masungi trail to teach visitors about the history of Masungi, the fossils that can be found in the area, “and the wealth of information we can get by studying them.”

In a press release, Masungi Georeserve said that the discovery “underscores the importance of protecting the limestone formations which are located between the Upper Marikina Watershed and Kaliwa Watershed, as well as within the National Park created through Presidential Proclamation 1636 in 1977.”

“The said areas continue to be threatened by various encroachments, illegal structures, and quarrying. Meanwhile, a 2,700-hectare forest restoration project - the Masungi Geopark Project - is being threatened with possible cancellation in favor of incompatible land uses,” the conservation area’s management said.

“We envision Masungi Georeserve as a place where educators, students, and local government can interact and collaborate in the study of karst features and processes and development of best practices in the management and conservation of karst landforms,” they added.

The Masungi Georeserve is an internationally acclaimed conservation area celebrated for its vibrant landscapes and extensive karst formations.

Situated at the base of the Sierra Madre mountains, Masungi is nestled within the vast Upper Marikina River Basin Protected Landscape, spanning 26,000 hectares. It also houses over 400 unique plant and animal species, some of which face the risk of endangerment.

Over the years, Masungi has had to parry off threats from quarry operators, resort owners and other entities who illegally occupy forestlands within the Upper Marikina Watershed. — with reports by Gaea Katreena Cabico