Varanus indicus species-complex

Varanus indicus species-complex

Ceram Monitor (Varanus cerambonensis)

Varanus cerambonensis was described in 1999 as part of the redefinition of Varanus indicus (Philipp, Böhme & Ziegler). They are known to occur in sympatry with indicus on at least one island (Ambon). However given the confused taxonomy regarding the indicus-complex, it is likely that as more specimens with specific locality data are examined it will be revealed that the two forms occur in sympatry on a number of islands.

Varanus cerambonensis is known to occur in lowland rainforests, often in close proximity to streams. This species is not known from the marine environments inhabited by indicus and so this  difference in habitat preference helps avoid competition in areas where these two occur together.

Distinctive Features (from Philipp, Böhme & Ziegler 1999)

Background color: Brownish-black

Dorsal pattern: Yellow to yellowish-white spots forming around five transverse bands

Tail pattern: Anterior third spotted as on the dorsal surface; posterior two thirds banded (blue pigmentation absent)

Throat/ventral pattern: Light (yellowish-white) and unpatterned

Post-ocular stripe: Present

Tongue color: Pink with a dark tip (in young, entirely pink)

Range

Known from the islands of Ceram, Ambon, Buru, and Banda Besar in the Moluccas. Records of this species from Obi appear to be inaccurate (Weijola 2010). Since this species was separated from Varanus indicus fairly recently, many records of indicus in this area may in fact refer to cerambonensis and this species range might be more extensive than currently known. Possibly occurs on neighboring parts of New Guinea, though this needs to be verified.

Photos courtesy of Sandi Purnomo. Note: This animal appears to conform to cerambonensis in all aspects except for tongue color, which is said to be dark blue (purple) vs. normally bi-colored (pink posteriorly/dark tips) in this species.

  Photo courtesy of Mo Chen.

Comparison of cerambonensis (top) vs. indicus (bottom). Photo courtesy of  Iqbal Hanif.

 What appears to be a specimen of cerambonensis (originally identified as indicus) from the Vogelkop Peninsula; the presence of this species in western New Guinea has been suggested by at least one museum specimen with vague locality data though field observations have yet to confirm this. Photo courtesy of Robert Sprackland.

Varanus c.f. cerambonensis 1

This animal is similar in some regards to Varanus cerambonensis such as overall color and pattern as well as tongue color (pink with a dark tip). However, it differs from cerambonensis in others, such as the shorter morphology of the head. Animals like this are typical of much of the indicus-complex: specimens resemble a known species in many aspects but differ enough in others that they cannot be placed with confidence. Again, I want to add that this animal does not appear to represent the normal definition of cerambonensis but is being included in this section due to general similarity and a lack (currently) of any other information. Photos courtesy of Mo Chen.

Same animals, different set of photos. Courtesy of Justin Burokas.

Varanus c.f. cerambonensis 2

This animal is similar to cerambonensis in color and pattern but differs in some respects, particularly head shape which is not as elongated as in most specimens. It probably does not represent cerambonensis but rather one of the countless unnamed members of this species complex which appear similar, but not identical to, described species. Photos courtesy of Dan Gill (Note: This specimen also appears similar to so-called "high-yellow indicus" which I have seen for sale from an unknown origin. If anyone else could venture a guess on this animal, please let me know)

Sources

Philipp, K. M.; Böhme, W. & T. Ziegler (1999): The identity of Varanus indicus: Redefinition and description of a sibling species coexisting at the type locality (Sauria: Varanidae: Varanus indicus group). Spixiana 22 (3): 273-287.

Weijola, V. S. A. (2010): Geographical distribution and habitat use of monitor lizards of the north Moluccas. Biawak 4 (1): 7-23. (http://www.varanidae.org/Vol4_No1.pdf)

Status in Captivity

Varanus cerambonensis has been imported for the pet trade and specimens appear on the market from time to time. It is probably more common than is realized due to its similarity to other indicus-type monitors, and with many specimens simply being sold as generic 'mangrove monitors'. Many monitor specimens which appear quite similar to - but differ in other aspects - cerambonensis turn up for sale (see above).