Varanus indicus species-complex

Varanus indicus species-complex

Peach-throated monitor (Varanus jobiensis)

Varanus jobiensis is a slightly-built species found throughout New Guinea and many of its satellite islands. It was originally described in 1932 as a subspecies of the mangrove monitor (Varanus indicus jobiensis). In 1951, Mertens described it as Varanus karlschmidti. In 1991, Böhme synonymized karlschmidti with jobiensis which was also elevated to full species. Numerous color morphs of this animal exist from different parts of the range, particularly insular populations, some of which may represent distinct races. It is believed that Varanus jobiensis may contain a number of cryptic forms (Horn 1997 and Böhme & Ziegler 1997; quoted from Philipp, Ziegler & Böhme 2004).

Varanus jobiensis occurs in alluvium forests, hill forests of moderate elevation (absent above a thousand meters), and swamps. They do not occur in mangroves (Bennett & Sweet 2009). They are strong climbers and are semi-arboreal in nature.

Distinctive Features

Background color: Dark olive, though some insular populations may appear dark grey to blackish

Dorsal pattern: Light-colored tiny (typically one but sometimes up to three scales in size) spots, arranged irregularly. Thin, dark transverse bands are present as well in most specimens but are absent in some populations

Tail pattern: Anterior half spotted as on the dorsal surface; posterior half banded (blue pigmentation typically present)

Throat/ventral pattern: Ventral surface pale and unpatterned; throat brightly colored (typically salmon-pink to light orange, but may also be yellow, bright orange, or reddish) and unpatterned. Some island populations lack bright coloration.

Post-ocular stripe: Present

Tongue color: Typically bright red with a black tip. Some specimens may have lighter-colored tongues and/or ones lacking dark pigmentation at the tip

Range

New Guinea (absent from the souther Trans-Fly Region; Bennett & Sweet 2009) as well as many nearby islands including Waigeo, Batanta, Salawati, Yapen and Biak and probably throughout the other Schouten Islands. Reports of this species from Halmahera have not been verified and are probably false.

Photos courtesy of Rune Midtgaard (http://www.natureswindow.dk/).

 The above photo is of a specimen from the island of Biak. Photo courtesy of Chris Lacey.

Varanus jobiensis - Variants

Several variants of Varanus jobiensis are known, many originating from the pet trade. While the localities of some of these are known (i.e. the islands of Waigeo and Batanta), others are not. With future taxonomic revisions, some of these many prove to be distinct forms.

Batanta

Varanus jobiensis from the tiny island of Batanta off the Vogelkop Peninsula of western New Guinea are considerably darker than mainland animals. Distinctive features of specimens from this locale include a lack of transverse bands across the dorsum, dorsal pattern being a light, dirty yellow to greenish in color, as well as a light-colored streak above the eye. Throat color also appears much reduced.Photo courtesy of Penta Exomania.

Waigeo

Like those from Batanta, Varanus jobiensis from Waigeo are dark animals lacking transverse dorsal bands. The pattern is a light grey in color, giving them the pet trade nickname 'silver-spot' jobiensis. Unlike normal jobiensis, these animals lack the bright throat coloration.

Photos courtesy of Danny Gunalen.

Photo courtesy of Justin Marois.

"Sunburst" jobiensis

The "sunburst" form of the peach-throated monitor is the name these extremely colorful animals go by in the pet trade. Note the clear transverse bands (present on normal jobiensis as well) and copious orange coloration. Not much else is available on them at the moment. I've heard various theories from dealers at shows about their origin (And, as in most cases, such claims need to be taken with a grain of salt) but most seem to think they originate from somewhere in West Papua (formerly known as Irian Jaya). But again, I am aware of no field observations or other hard data to back this up.

Photos courtesy of Lokalers Indonesia.

Unknown locality

These photos show a specimen (originally identified as Varanus caerulivirens) from an unknown origin. They are similar to jobiensis from Waigeo (see above), though I heistate to identify them as such if only because I have never seen juvenile Waigeo animals. Further details on these animals would be appreciated. Photos courtesy of Tengku Noval Rizki (AIS-ReptilX).

Status in Captivity

Varanus jobiensis has been maintained for years in captivity and remains one of the most available members of this species-complex. They may also be one of the few members which can be maintained to any real degree (A necessary note on this point: indicus-type monitors in general make very poor captives and imported specimens make horrible ones. The comment on jobiensis is to be taken only in the realm of relativity... this is by no means a simple animal to keep and it should only be done by those with prior Varanid experience and a healthy understanding of this species). While this species has been bred in captivity, most specimens continue to be imports. They are regularly available and do not command high prices; an unfortunate fact for those inclined to make impulse purchases of attractive animals. For an account of the captive maintance and breeding of this species see Stefani (2008).

Sources

Bennett, D. & Sweet, S. S. (2009): Varanus jobiensis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. (http://www.iucnredlist.org/apps/redlist/details/178029/0) 

Böhme, W. (1991): New findings on the hemipenal morphology of monitor lizards and their systematic implications. Mertensiella 2: 42-49.

Mertens, R. (1951): A new lizard of the genus Varanus from New Guinea. Fieldiana, Zoology 31 (43): 467-471.

Philipp, K. M.; Ziegler, T. & W. Böhme (2004): Varanus jobiensis. In: Pianka, E. R.; King, D. R. & R. A. King (eds.), Varanoid Lizards of the World. Indiana University Press. Bloomington, Indiana: 189-192.

Stefani, M. (2008): Husbandry and Reproduction of the Peach-throated Monitor Varanus jobiensis in Captivity. Biawak 2 (3): 124-130. (http://www.varanidae.org/Vol2_No3.pdf)