Varanus indicus species-complex

Varanus indicus species-complex

Blue-tailed Monitor (Varanus doreanus)

Varanus doreanus was originally described in 1874. However, the only specimen was destroyed in World War II during the Allied bombing of Dresden and so remained essentially unknown until 1994 when the species was rediscovered (Böhme, Horn & Ziegler). This species is sometimes referred to by the invalid name 'Varanus kalabeck', especially in the pet trade. Some regional variations of doreanus are known, particularly the 'orangespot' phase.

Varanus doreanus inhabits rainforests (particularly alluvial forests), highland jungle, and monsoon forest and exist to elevations of at least 1500 meters. They do not appear to occur in mangroves and avoid coastal areas in general. They may be found in semi-open locations such as river beds with more regularity than other indicus-complex monitors. Varanus doreanus may be one of the more terrestrial members of the indicus-complex, though they are certainly capable of climbing.

Distinctive Features

Background color: Dark greyish-blue to black

Dorsal pattern: Yellowish ocelli possessing dark centers, typically arranged in transverse rows (Note: Ontogenetic change in pattern is especially strong in this species. Young animals display solid yellow spots on the dorsum, often arranged in transverse rows. Pattern gradually fades over time to a more blended appearance in adults)

Tail pattern: Base of tail spotted; remainder strongly banded (blue pigmentation present)

Throat/ventral pattern: Underside whitish; throat spotted to marbled; ventral surface banded

Post-ocular stripe: Absent

Tongue color: Yellow to whitish

Range

Known from New Guinea (absent from higher elevations in the interior) as well as many smaller islands including Waigeo, Batanta, Salawati, Biak and the Schouten Islands, Jobi (Yapen), and the Aru Islands. Might occur on others as well. A record of this species from Halmahera exists (Ziegler et al 2007), though later field work does not seem to support this species' occurrence here (Weijola 2010). Also occurs in the Cape York Peninsula, Australia though exact localities are sparse.

Juvenile

 Locale: Salawati. Photo courtesy of Jody Pieper.Locale: Sorong, West Papua (Irian Jaya). Photo courtesy of Jody Pieper.

Locale: Sorong, West Papua (Irian Jaya). Photo courtesy of Danny Gunalen.Locale: Wamena, West Papua (Irian Jaya). Photo courtesy of Jody Pieper.

 Locale: Chilli Beach, Iron Range, Queensland, Australia. Photo courtesy of Dr. D. Brown. Note: the occurrence of Varanus doreanus in Australia has only been established relatively recently (Ziegler et al 2001). This is the only photograph of a live Australian doreanus that I am aware of.

 

Juvenile doreanus-type animal, origin unknown. Has spotted pattern and barred throat indicative of doreanus though the colors appear brighter than usual. Photo courtesy of Ibram Santos.

Adult

Photo courtesy of Rune Midtgaard (www.natureswindow.dk).

Varanus doreanus - Orangespot phase

Several variants of Varanus doreanus are known through importation for the pet trade. One such animal is known as the 'orangespot' phase. These specimens appear similar to normal doreanus but possess a distinct orange hue. Locality information is sparse. Pet trade rumor has this form as coming from somewhere in West Papua (formerly known as Irian Jaya), possibly northern coastal locations (** info update.. see below **).

Photo courtesy of Danny Gunalen.

Photo courtesy of Tengku Noval Rizki (AIS-ReptilX). Note: this animal is said to originate from Jayapura in West Papua. Though I am not aware of the history and accuracy of this claim (and this most likely represents only where it was procured by a middleman, not the animal's original locality), this is the only specific locality I am aware of for an orange-phase doreanus specimen. If anyone has heard other claims of specific localities I would be very interested.

 Different locality specimens: Merauke (left) and Jayapura (right). Again, it must be emphasized that these animals (and the locality data to go with them) represent pet trade specimens, so the reliability must be considered tentative. Photo courtesy of Yance Hanzie.

Varanus doreanus - Pastel phase

'Pastel' doreanus is the name given to certain light-colored doreanus-type animals in the pet trade.

An unknown doreanus variant. Photo courtesy of Danny Gunalen.

Photo courtesy of Justin Marois, who mentions that these are the same animals (older) as the one pictured above. They are believed to originate from the Bewani Mountain region in northwestern Papua New Guinea, though the accuracy of this claim cannot be verified (It should be noted that PNG does not allow for the exportation of wildlife for the pet trade, although smuggling is by no means unknown in the world).

Status in Captivity

Varanus doreanus is one of the more common indicus-complex species in the pet trade; not particularly a good thing since they are extremely temperamental and unless the appropriate conditions are provided make poor captives. The physical beauty of this species also lends itself well to becoming impulse purchases among keepers unfamiliar with it. Captive breeding for this species has thus far been almost nonexistent and available specimens are virtually guaranteed to be imports. Orange phase specimens are imported occasionally, though I’ve seen fewer in recent years. Pastel phase animals are also imported rarely, but even less often than the orange.It would be wonderful if doreanus were to become established in captivity so that CB animals are available for those dedicated enough to work with them, though this seems unlikely anytime soon. Make sure you know what you are getting into before buying this species!

Sources

Böhme, W.; Horn, H. & T. Ziegler (1994): On the taxonomy of the Pacific monitor lizards (Varanus indicus complex): Resurrection of Varanus doreanus (A.B. MEYER, 1874) and description of a new subspecies. Salamandra 30 (2): 119-142.

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)

Ziegler, T.; Böhme, W.; Eidenmüller, B. & K. M. Philipp (2001): A note on the coexistence of three species of Pacific monitor lizards in Australia (Sauria, Varanidae, Varanus indicus group). Bonn. Zool. Beitr. 50 (1-2): 27-30.

Ziegler, T., Schmitz, A., Koch, A. & W. Böhme (2007): A review of the subgenus Euprepiosaurus of Varanus (Squamata: Varanidae): morphological and molecular phylogeny, distribution and zoogeography, with an identification key for the members of the V. indicus and the V. prasinus species groups. Zootaxa 1472: 1-28.