SO, WHAT SPECIES DO THE LAGUNA MONITORS BELONG TO?

The big question that needs addressing now is, what is the identity of the Laguna monitors?

At the time of V. dalubhasa’s description, the authors had 10 specimens examined, sampled from one municipality on Catanduanes island, one municipality each for Camarines Norte and Camarines Sur, three municipalities in Quezon, and on the island of Polillo. Eleven specimens of V. marmoratus were examined, from the islands of Batanes, Calayan, and Lubang, and on the Luzon proper in Ilocos Norte, Aurora, and Bulacan. No specimens were examined from the other southern Luzon towns surrounding Quezon, possibly due to the belief that what occurs in these areas are V. marmoratus.

If there is one fault I can ascribe to an otherwise wellwritten paper, it’s that it did not survey the provinces of Cavite, Rizal, and Laguna for Varanus. Doing so might have yielded additional insights into the distribution of V. dalubhasa.

The similarity of one Laguna specimen to V. bangonorum, at least with regards to the neck patterning, is even more perplexing, especially as currently understood, the species is restricted to Mindoro and Semirara islands. The deep waters around these islands are supposedly enough barrier to prevent the interisland crossing of monitors, but what could possibly explain the V. bangonorum-like individual in Laguna?

One possible key to the mystery is that V. dalubhasa (assuming for the meantime that the Laguna population belongs to this species) is more variable than previously thought, and that in other parts of its range it displays patterning, particularly on the neck, approaching that of V. bangonorum. This possibility may have been overlooked by the authors of

V. dalubhasa. The implication in this scenario is that the neck patterning is of no significance to the delimitation between both V. dalubhasa and

V. bangonorum, and that the Laguna monitors have indeed be the former.

Nevertheless, one may begin asking questions if, due to a possible overlap of ranges on Luzon, V. marmoratus and V. dalubhasa are capable of reproducing and thus produce hybrid swarms. I personally am not equipped with enough tools to answer that, although it is certainly a possibility. After all, no one really knows at this juncture where the overlap exactly is, or if both

V. marmoratus and V. dalubhasa share the same ecological niche in some unspecified locality.

For what it’s worth, it seems that the Laguna monitors do belong to V. dalubhasa, but the population exemplify how gular patterning is of very little use in distinguishing between it and the unrelated V. bangonorum – something that the authors weren’t aware of at the time of the two species’ descriptions.

In this vein, a point that I feel needs raising here is that there is a tendency among researchers to state that V. dalubhasa is endemic to the Bicol region, such as in a paper by Binaday et al (2017). Even without elucidating the species’ apparent presence in the province of Laguna, it was stated clearly in its protologue (Welton et al, 2014) that apart from the Bicol region, it also is found in both the province of Quezon and the island of Polillo.