Two Romblon-endemic reptiles rediscovered in Mt. Guiting-Guiting survey

Field biologists from the UPLB Museum of Natural History and their international collaborators are elated with the formal announcement of their rediscoveries of two reptiles – a skink and a gecko – as a result of field expeditions done in Sibuyan Island, Romblon in 2016 and 2017.

According to Camila Meneses, a junior researcher who led the two herpetofaunal survey expeditions in Sibuyan’s Mt. Guiting-Guiting, said that they have been able to find, collect and ascertain the identify of the secretive and elusive Brachymeles dalawangdaliri (Scincidae) and Pseudogekko isapa (Gekkonidae).

B. dalawangdaliri and P. isapa can only be found in the Romblon Island Group and nowhere else in the world.

“The skink Brachymeles dalawangdaliri was first described by an international group of scientists in 2016 based on specimens that were collected in 1970s in the adjacent Tablas Island,” Meneses relayed during an interview.

On the other hand, Pseudogekko isapa, one of only seven recognized species of Philippine false geckos and also described in 2016, was based on only two specimens. The first was collected in Tablas Island 50 years ago while the other in Mt. Guiting-Guiting in 2014.

On lizards, snakes and skinks

The number and uniqueness of lizards, snakes and skinks found in the Philippines are proofs of the remarkable diversity of reptiles in the country. However, appreciation for these cold-blooded animals is somewhat diminished by fear partly brought by poor understanding of their differences.

“Some people think that the three groups are one and the same, hence they lump them all together as snakes with deadly venom and should be exterminated,” Meneses explained

Although lizards and snakes are related, they are easily distinguished from one another by their skins and legs. We usually think of lizards as four-legged reptiles with scaly skin, movable eyelids and external ears. But according to Meneses, it would be wise for people not to overgeneralize.

“There are some lizards which lack these general features but rather exhibit superb unique distinguishing features, say for example, limb degeneration and loss. Hence, these lizards can be misidentified as snakes,” she explained. “Brachymeles dalawangdaliri is a great example, it has legs too small to be easily recognized and has only one to two toes per limb,” she added.

The Philippines also has small endemic clades of secretive, limb-reduced, loam-swimming skinks and cryptic slender geckos. There are lizards that looks like the Common House Gecko or butikî but has other characters that cannot be found in other gekkonid lizards.

New information on rare species

Although the descriptions of B. dalawangdaliri and P. isapa as new species were fairly recent, the bases were made only through the use of few and old museum specimens collected in the early 1970s. The expeditions made by Meneses through the auspices of the Mt. Guiting-Guiting Natural Park Protected Area added more specimens to current national and international collections and have enabled better taxonomic and molecular diagnostic work.

“Fifty years ago, molecular sampling and application of modern phylogenetic analyses were not yet practiced, so when we talk of standard morphological variation, researchers back then have been unable to fully assess characters that are important to correctly diagnose and identify specimens because the original type series for each species consisted of only a few specimens,” she explained.

According to their group’s paper recently published in the Philippine Journal of Systematic Biology 14:2-2, the recent rediscoveries provide an improved understanding of genetic and morphological variation of these Romblon Island Group endemic species based on comprehensively examined recent available specimens and newly obtained data.

The group is composed of Meneses, Dr. Juan Carlos T. Gonzalez (UPLB Museum of Natural History) Dr. Rafe Brown (University of Kansas), Dr. Perry Wood, Jr. (Auburn University) and Dr. Cameron Siler (Oklahoma University). Their data allowed for the first time the statistical characterization of both species’ intraspecific variation, estimated phylogenetic relationships, inference of biogeographic affinities and as well as interspecific comparison with congeners in both Romblon Island Group endemic species.

Difficult collection

Mt. Guiting-Guiting is one of the most difficult mountains to climb in the Philippines, hence it is quite understandable why almost half a century has already passed before new reptile surveys in the mountain have been made.

“Setting up traps in the northern slope of the mountain is very challenging since it is a ridge with only few safe places to set up traps,” Meneses recalled. “To put up pitfall traps, we have to dig very had because intertwined roots and ultramafic rocks were all over the place,” she added.

“We caught most of the B. dalawangdaliri individuals under big boulders of ultramafic rocks and rotten logs along the elevation gradient,” the young researcher said. Interestingly, Meneses and her field assistants caught their first one hiding in the topsoil of an unlikely area, a habitat type different to the 1972 specimens which were collected in a primary forest in Tablas Island.

On the other hand, Meneses thought that the Pseudogekko samplings, which were done at night, fun and interesting despite the obvious difficulties and risks. She had people sampling in teams of five to lessen the need for quick and dangerous movements while searching at the edge of ravines.

P. isapa is a slender lizard and easily camouflages itself in its surroundings. “It becomes very aware of imminent threat when spotted with light and will either slowly maneuver itself and hide among small branches of trees and vines or rapidly jump to another location,” Meneses explained.

Importance of collaborative museum work

While Meneses believed that continued surveys in small island groups will lead to more species discoveries and greater understanding of Philippine biogeography and species boundaries, she also asserted that museum collections are very important resources.

“Although we collected 7 individuals of B. dalawangdaliri and 15 specimens of P. isapa for molecular work, we also heavily relied on numerous reptile collections from the Philippine National Museum, California Academy of Sciences, Kansas University, Texas Natural History Collections, Field Museum of Natural History, and the UPLB Museum of Natural History,” Meneses said.

She also expounded on the importance of intensified collaborations between natural history museums as digging for historical accounts to ameliorate some of the shortcomings in past are also keys to improve understanding of Philippine endemic rare species.

“We are proud to say that our recent paper is the first report on the first molecular estimates, based on new data, the phylogenetic relationship and phenotypic variation of these two secretive and poorly known endemic species to the Romblon Island Group,” she remarked.

More conservation efforts needed in Mt. Guiting-Guiting

The rediscoveries of these enigmatic species along the elevational gradient of Mt. Guiting-Guiting Natural Park, specifically in Sitio Logdeck, Barangay Tampayan in the town of Magdiwang, Sibuyan, Romblon strengthens the evidence that this small island group should be considered as a fragile faunal subregion which needs stricter and increased protection and conservation.

“As both species have secretive behavior, they have specific microhabitat requirements which unfortunately are threatened by extensive habitat degradation,” Meneses said.

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