Marbled Water Monitor

As their common name suggests, water monitors are a semi-aquatic lineage, prefering lowland to mid-elevation riparian habitats.

Varanus marmoratus 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 elevated to species status by Koch et al. (2007). Varanus marmoratushas a dark gray to black ground color overlain with a variable number of transverse rows of small yellow oscelli; nuchal scales with; tail overlain with light bands and white speckling distally; limbs dark gray to black, with minimal, variable white speckling. Ventral coloration light cream, with irregular dark gular spotting, or occasional transverse bands; trunk with variably discernable transverse bands, often becoming more distinct latterally; limbs cream, with minimal variable dark specklingVar. Tail light cream proximally, dark gray distally.

Varanus marmoratus is fairly common throughout its range, despite being threatened by collection for skin and pet trades, as well as for bush meat.

Varanus marmoratus is 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 marmoratus is a relatively small member of the V. salvator Species complex, characterized by a near black dorsal ground color, with transverse bands consisting of a variable number of yellow-white oscelli; bands become solid on the tail. Ventrally, this species is characterised by a cream color throughout, with dark gular speckles or transverse bands, as well as dark speckles on the limbs.

Varanus marmoratus 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) narial opening one-third distance from tip of snout to ocular; (2) low numbers of scales around tail at one-third distance from base; (3) low numbers of midbody scales; (4) high numbers of ventral scales; (5) relatively large dorsal scales and corresponding low dorsal scale counts; (6) relative small oscelli comprising first transverse dorsal band in axilla–groin region; (7) creamy white venter, with a maximum of five dark gular transverse bands; and (8) transverse dark, ventral bands totalling 6–11 (Koch et al., 2007).

Varanus marmoratus has been documented throughout the Greater Luzon Faunal Region, including the Batanes and Babuyan island groups, and Catanduanes, Lubang, Mindoro, Polillo, and Luzon islands.

As with many species of monitor lizards, Varanus marmoratus 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 likely chosen from the Latin marmoratus (= marbled), in referrence to the "marbled" dorsal patterning exhibited in this species.

Luzon Pleistocene Aggregate Island Complex

Varanus marmoratus like all water monitors, is often found in disturbed to primary growth riparian habitats in low- to mid-elevations.

Varanus marmoratus most closely resembles other Philippine members of the V. salvator Species Complex, but is readly distinguished by speckled or banded gular coloration and the light posterior margins of nuchal scales.

Varanus marmoratus, 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 marmoratus are likely from unsustainable harvest (for trade and bush meat) and habitat loss.

Continent: Asia
Distribution: Philippine Islands (Luzon); restricted to Luzon and offshore islands by KOCH et al. 2010.
Type locality: (restricted by MERTENS 1942 to) San Mateo near Manila, Philippines. Mertens decision, although adopted by later authors (e.g., Böhme 2003; Koch et al. 2007), was not conform to Article 76 of the International Code for Zoological Nomenclature (ICZN 1999), because no neotype was designated at the same time.

The marbled water monitor (Varanus marmoratus), also known commonly as the Philippine water monitor, is a large species of monitor lizard in the family Varanidae. The species is endemic to the Philippines.