A parthenogenetic Varanus.

Amphibia-Reptilia 26(4):507-514. DOI:10.1163/156853805774806296.

Abstract:

We report on a case of parthenogenesis in the varanid lizard Varanus panoptes. Parthenogenesis was observed in a female kept alone for three years. A clutch was deposited from which a single egg could be secured and incubated. Incubation was successful and a male specimen hatched. Obviously the newborn was produced without contribution of a father. After the unisexual reproduction, the mother was kept with males and bisexual reproduction was observed, too. We performed DNA Fingerprinting and showed that the parthenogen and its mother exhibit almost identical DNA patterns. The bisexually produced offspring has only a subset of bands in common with the mother and another subset in common with the father. Thus DNA Fingerprinting is in accordance with our observations and confims parthenogenesis.We compare our results with existing cytological models of parthenogenesis and point out the following: 1. The mode of parthenogenesis described here is facultative, as the mother was able to reproduce in the bisexual mode as well. 2. The parthenogen is male and hence not a clone of the mother. 3. Almost complete heredity of maternal Fingerprint markers. All these points considered our case seem to fit to no known model of parthenogenesis exactly. But an additional recombination could result homogamety (would explain the sex of the parthenogen) while expressing almost all maternal bands.

lenk-biblio

A molecular phylogeny of the Australian monitor lizards (Squamata:Varanidae) inferred from mitochondrial DNA sequences.

Australian Journal of Zoology. 54: 253–269.

Volltext: https://www.researchgate.net/publication/248902243_A_molecular_phylogeny_of_the_Australian_monitor_lizards_Squamata_Varanidae_inferred_from_mitochondrial_DNA_sequences

Abstract:

To date no complete phylogeny of all of the currently recognised Indo-Australian varanid species and subspecies has been published. This paper presents a comprehensive mitochondrial gene phylogeny of these lizards. A portion of the mitochondrial genome comprising part of the ND4 gene and three adjacent tRNA genes (hereafter referred to as ND4) was analysed alone and, for a subset of the taxa, combined with previously published mitochondrial data. Similar tree topologies were produced by both datasets although combining the data helped resolve some of the unresolved or weakly supported nodes in the ND4 analyses. The monophyly of the Indo-Australian group was strongly supported in all analyses. This group comprised three major lineages: the gouldii group, the Odatria group and the varius group. Mitochondrial ND4 nucleotide sequences were successfully amplified from all of the Indo-Australian monitor species and subspecies currently recognised and, as such, is the first comprehensive phylogenetic study of the Australian monitor lizards published. Analysis of the tempo of diversification and evolution of preferred habitat use identified six episodes of increased net speciation rate, with two closely adjacent episodes showing the highest rates of diversification and correlating with the appearance of all preferred habitat types. The comprehensive molecular phylogenetic framework will also be useful for the identification of varanid species and traded products derived from monitors and, as such, has important applications for wildlife management and conservation.

fitch-biblio

Husbandry Guidelines for PERENTIE.

71 Seiten. Australasian Association of Zoo Keepring

Volltext: https://aszk.org.au/wp-content/uploads/2020/04/Reptiles.-Perentie-2010RR.pdf

Introduction:

The Perentie is classed as dangerous and can cause serious harm or death. Two trained
keepers must be present at all times when entering this exhibit. National Parks and Wildlife Services (NPWS) list the Perentie as a Class 2 species (Species code number Z2267), indicating that the species is either rare, difficult to keep and/or potentially dangerous venomous species may be kept only under a Class 2 licence. All applicants for a Class 2 licence must be over the age of 18 years with at least 2 years experience keeping reptiles.

NB: Bei dem Dokument handelt es sich um einen  nicht fertiggestellten Entwurf.

rymann-biblio

Über die Nachzucht des australischen Riesenwarans Varanus giganteus (Gray, 1845) (Sauria: Varanidae)

Salamandra 23 (2/3): 90-96.

Zusammenfassung:

Beobachtungen bei der erstmals beschriebenen Nachzucht von Varanus giganteus werden mitgeteilt. Aus einem Gelege von 11 Eiern, von denen eines bei der Bergung des Geleges zerstört wurde, schlüpften 6 Jungtiere, ein Tier verstarb unmittelbar nach dem Schlupf. Beim Schlupf wiesen die Jungtiere eine durchschnittliche Gesamtänge von 375,3 mm und ein Durchschnittsgewicht von 40 g auf; die Zeitigungsdauer betrug durchschnittlich 231,5 Tage bei 30-32°C in Sphagnum un d85 % relativer Luftfeuchte.

bredl-biblio

The reproduction and husbandry of the Water monitor Varanus salvator at the Gladys Porter Zoo, Brownsville.

Int. Zoo Yb. 31: 124-130.

Inhalt:

Es wird über die Erfahrungen bei der Haltung und Zucht von Bindenwaranen während 14 Jahren berichtet.

Bisher unbekannte Details zur Kenntnis von Varanus varius auf Grund von feldherpetologischen und terraristischen Beobachtungen (Reptilia: Sauria: Varanidae)

Salamandra 16 (1): 1-18.

Zusammenfassung:

Die gebänderte Form von Varanus varius ist keine distinkte Unterart. Durch Bestimmung der Geschlechtszugehörigkeit von 22 Exemplaren der bellii-Phase wird nachgewiesen, daß Warane der bellii-Phase stets männlichen Geschlechts sind. Es handelt sich also um eine geschlechtsgebundene Farbmutante. Verschiedene Beobachtungen zum Verhalten des Buntwarans im Freien werden mitgeteilt. Ebenso werden Beiträge zum Verhalten in Gefangenschaft geliefert; so wird beispielsweise über eine selten eingenommene Drohhaltung des Buntwarans berichtet. Verschiedene
Situationen des Verhaltens werden durch Fotos dokumentiert. Ferner wird das in der Literatur verstreute Material zur Fortpflanzung von V. varius kompiliert und kritisch gesichtet.

A Dubious Account of Breeding Varanus olivaceus in Captivity at the Paradise Reptile Zoo in Mindoro, Philippines.

Biawak, 8(1), pp. 12-14
© 2014 by International Varanid Interest Group

Abstract: 

Varanus  olivaceus is one of the most valuable monitor lizards in wildlife trade and considered vulnerable throughout its range.  A published report claiming “the world’s first successful breeding of V. olivaceus” is reviewed critically in the light of established facts about the reproduction of this species in captivity, and experience of the establishment in question in the year of the supposed breeding.  Regulatory authorities and peer reviewers should require unambiguous proof of captive breeding success before accepting such claims in the future.

Parthenogenesis in Komodo dragons.

Nature 444, 1021-1022 (21 December 2006) | doi:10.1038/4441021a; Received 4 October 2006; Accepted 16 November 2006; Published online 21 December 2006.

Abstract:

Should males and females be kept together to avoid triggering virgin birth in these endangered reptiles?

Parthenogenesis, the production of offspring without fertilization by a male, is rare in vertebrate species, which usually reproduce after fusion of male and female gametes. Here we use genetic fingerprinting to identify parthenogenetic offspring produced by two female Komodo dragons (Varanus komodoensis) that had been kept at separate institutions and isolated from males; one of these females subsequently produced additional offspring sexually. This reproductive plasticity indicates that female Komodo dragons may switch between asexual and sexual reproduction, depending on the availability of a mate — a finding that has implications for the breeding of this threatened species in captivity. Most zoos keep only females, with males being moved between zoos for mating, but perhaps they should be kept together to avoid triggering parthenogenesis and thereby decreasing genetic diversity.

Notizen zu Systematik, Fundortangaben und Haltung von Varanus (Varanus) karlschmidti (Reptilia, Sauria, Varanidae).

Salamandra 13 (2): 78-88.

Zusammenfassung:

Es werden die systematischen Merkmale von vier weiteren Exemplaren von Varanus karlschmidti beschrieben sowie über die Haltungsbedingungen und das Verhalten der lebenden Tiere im Terrarium berichtet. Die Fundorte werden tabelliert und Klimadaten nahe gelegener Orte in Beziehung zur möglichen Lebensweise der Tiere gesetzt.

International Trade in the Blue Tree Monitor Lizard Varanus macraei.

Biawak, 9(2), pp. 50-57
© 2015 by International Varanid Interest Group

Abstract:

Using Convention on International Trade in Endangered Species (CITES) trade statistics derived from the CITES Trade Database (UNEP World Conservation Monitoring Centre, Cambridge, UK), published literature and anecdotal information from the internet, the wildlife trade in Varanus macraei is described. The lizard is a high value pet commodity and although it is traded in relatively small numbers, virtually all trade appears to be of animals harvested directly from the wild population on Batanta Island, Indonesia. Export data suggests an extraction rate of over 6.6 individuals per km² over a decade, with a total value of between US $1-2 million. Trade to some countries including Russia, Taiwan and Ukraine is underestimated or omitted by import data. Overall trade in the species is increasing and prices have remained high despite captive breeding events in Europe and the United States, with captive bred animals representing less than 1% of worldwide trade.