As their common name suggests, water monitors are a semi-aquatic lineage, prefering lowland to mid-elevation riparian habitats.
Varanus palawanensis is a member of the sub-genus Soterosaurus (Ziegler and Bӧhme, 1997), which is comprised of the V. salvator Species Complex and V. rudicollis. This taxa was formally described by Koch et al. (2007). This species has a dark brown ground color, with occasional single-scale light speckles; light transverse bands generally not discernable, although becoming slightly more so through the distal second half of tail; light spotting most conspicuous on limbs. Ventral color cream; snout with up to three dark transvers bands; gular region mottled; trunk with medially-faded, dark transverse bands; tail cream proximally, becoming darker distally.
Varanus palawanensis is very common throughout its range, despite being threatened by collection for skin and pet trades, as well as for bush meat.
Varanus palawanensisis designated as a CITES Appendix II species. This taxon is not currently threatened by extinction, but may become so unless trade or other factors are closely monitored.
Varanus palawanensisis the largest Philippine member of the V. salvator Species Complex, characterized by an overall dark coloration with variably arranged yellow-gold speckling, not present as discernible transverse dorsal body bands. Ventrally, this species is characterized by up to three transverse chin bands, and variable gular mottling.
Varanus palawanensis can be distinguished from all non-Soterosaur Varanus species by characteristics of reproductive morphology (See Ziegler and Bӧhme, 1997). This species can be distinguished from all other members of the V. salvator Species Complex and V. rudicollis by combinations of: (1) high numbers of rictus–rictus head scales; (2) low numbers of mid-body scales; (3) low numbers of dorsal scales; (4) indistinct dorsal mottling pattern; (5) often moderate white head patterning; (6) poorly tefined temporal stripe, extending from ocular to tympanum; (7) a dark blue to gray tongue, flesh-colored at its base; and (8) variable gular mottling (Koch et al., 2010).
Varanus palawanensis has been documented throughout the Palawan Faunal Region, including the Calamian islands, as well as Balabac and Palawan islands. Photographic evidence suggests this species presence additionally on islands of the Sulu Archipelago (namely Sibutu and the Sulu Group).
As with many species of monitor lizards, Varanus palawanensis is an opportunistic feeder, and will seek out various sources of carion, as well as consuming small reptiles, amphibians, rodents, fish, and both terrestrial and aquatic arthropods.
The specific epithet was chosen in reference to the type locality for this species, Palawan Island, Philippines.
Palawan Pleistocene Aggregate Island Complex
Varanus palawanensis like all water monitors, is often found in disturbed to primary growth riparian habitats in low- to mid-elevations.
Varanus palawanensis most closely resembles other Philippine members of the V. salvator Species Complex, but is readly distinguished by its lack of discernible dorsal body bands.
Varanus palawanensis, like all water monitors, is rather successful in moderately disturbed habitat, so long as some in-tact riparian habitat remains and populations are not overly stressed by harvest.
The most severe threats to Varanus palawanensis are likely from unsustainable harvest (for trade and bush meat) and habitat loss.
The Palawan water monitor (Varanus palawanensis) is a quite large species of monitor lizard in the family Varanidae. The species is endemic to the Philippines.[1]
Varanus palawanensis can reach total length of (including tail) 2 metres (6,6 ft).[2]
The best studied water monitor population of the Philippines is that of Calauit ( Gaulke 1989 ), a small islet belonging to the Calamian Island Group at the north-easterly margin of Palawan Province. Gaulke ( 1989 ) provided morphological data for 167 specimens . The longest specimen had a total length of 1880 mm with parts of its tail missing. The smallest specimen measured only 390 mm from the tip of the tail to the tip of the snout. Latter specimen had a snout-vent length of 14 cm, while the largest measured 78.8 cm . The mean snout-vent length was 54.77 cm.[2]
Varanus palawanensis has enough differences to be considered a distinct species[3] from the closely related V. salvator (water monitor), V. marmoratus (marbled water monitor), and V. rasmusseni. V. palawanensis belongs to the subgenus Soterosaurus with these three species and several other species.
Varanus palawanensis is found on the islands of Palawan, Busuanga, Calauit, Balabac, and Sibutu.[1]
The Palawan water monitor (Varanus palawanensis) is a quite large species of monitor lizard in the family Varanidae. The species is endemic to the Philippines.
