Preliminary studies of alfaxalone for intravenous immobilization of juvenile captive estuarine crocodiles ( Crocodylus porosus ) and Australian freshwater crocodiles ( Crocodylus johnstoni ) at optimal and selected sub–optimal thermal zones

2013 ◽  
Vol 40 (5) ◽  
pp. 494-502 ◽  
Author(s):  
Annabelle Olsson ◽  
David Phalen ◽  
Christina Dart
Keyword(s):  
Crocodylus Johnstoni ◽  
Crocodylus Porosus ◽  
Australian Freshwater

Morphometric analysis of the Australian freshwater crocodile (Crocodylus johnstoni)

2017 ◽  
Vol 65 (2) ◽  
pp. 97 ◽  
Author(s):  
Glenn P. Edwards ◽  
Grahame J. Webb ◽  
S. Charlie Manolis ◽  
Alex Mazanov
Keyword(s):  
Morphometric Analysis ◽  
Body Measurements ◽  
Body Parts ◽  
Allometric Growth ◽  
Relative Growth ◽  
Crocodylus Johnstoni ◽  
Arnhem Land ◽  
Freshwater Crocodile ◽  
Crocodylus Porosus ◽  
Australian Freshwater

We conducted a morphometric analysis of 279 Crocodylus johnstoni, using specimens from the McKinlay River (n = 265) and Arnhem Land (n = 14), to meet the management need for predicting body size of C. johnstoni from isolated body parts. The results also allow reconstruction of C. johnstoni dimensions for comparison with other crocodilian species. We detected sexual dimorphism in some body measurements from the McKinlay River, and geographic variation in the morphology of McKinlay River and Arnhem Land populations, but differences were slight. There is pronounced allometric growth in C. johnstoni in the immediate post-hatching phase, largely due to elongation of the snout after exiting the confines of the egg. We compared the size, shape and relative growth of C. johnstoni with that of other crocodilian species for which equivalent data are available, but particularly the other Australian crocodile, Crocodylus porosus. C. porosus has a proportionately longer tail and a shorter but wider snout than C. johnstoni, and we discuss possible ecological correlates of these and other differences.

Remote monitoring of crocodilians: implantation, attachment and release methods for transmitters and data-loggers

2009 ◽  
Vol 60 (4) ◽  
pp. 284 ◽  
Author(s):  
Craig E. Franklin ◽  
Mark A. Read ◽  
Peter G. Kraft ◽  
Niko Liebsch ◽  
Steve R. Irwin ◽  
...  
Keyword(s):  
Physiological Variables ◽  
Crocodylus Johnstoni ◽  
Data Loggers ◽  
Archival Tags ◽  
Crocodylus Porosus ◽  
Electronic Tags ◽  
Free Ranging ◽  
Australian Freshwater ◽  
Term Management

Crocodilians are by their very nature difficult animals to study. However, research on wild animals is essential for the development of reliable long-term management. Here, we describe methods for the acquisition and monitoring of behavioural and physiological variables from free-ranging crocodilians through the use of archival tags (data-loggers) and via satellite, radio and acoustic telemetry. Specifically, the attachment or implantation of electronic tags is described and examples provided of the type of data that can be collected. Our research group has used a combination of approaches to monitor the movements, diving activity, body temperatures and heart rates of crocodilians, including studies on the Australian freshwater crocodile (Crocodylus johnstoni), the estuarine crocodile (Crocodylus porosus) and the caiman (Caiman latirostris). Each approach or method presents unique challenges and problems, chiefly as a consequence of differences in body morphology and size of the crocodilian species, their behaviours and the habitats they occupy.

scholarly journals Intra- and interspecific agonistic behaviour in hatchling Australian freshwater crocodiles (Crocodylus johnstoni) and saltwater crocodiles (Crocodylus porosus)

2013 ◽  
Vol 61 (3) ◽  
pp. 196 ◽  
Author(s):  
Matthew L. Brien ◽  
Grahame J. Webb ◽  
Jeffrey W. Lang ◽  
Keith A. Christian
Keyword(s):  
Interspecific Interactions ◽  
Open Water ◽  
Agonistic Behaviour ◽  
Agonistic Interactions ◽  
Crocodylus Johnstoni ◽  
Clear Winner ◽  
Crocodylus Porosus ◽  
Species Specific ◽  
High Level ◽  
Australian Freshwater

We examined agonistic behaviour in hatchling Australian freshwater crocodiles (Crocodylus johnstoni) at 2 weeks, 13 weeks, and 50 weeks after hatching, and between C. johnstoni and saltwater crocodiles (Crocodylus porosus) at 40–50 weeks of age. Among C. johnstoni, agonistic interactions (15–23 s duration) were well established by two weeks old and typically involved two and occasionally three individuals, mostly between 17 : 00 and 24 : 00 hours in open-water areas of enclosures. A range of discrete postures, non-contact and contact movements are described. The head is rarely targeted in contact movements with C. johnstoni because they exhibit a unique ‘head raised high’ posture, and engage in ‘push downs’. In contrast with C. porosus of a similar age, agonistic interactions between C. johnstoni were conducted with relatively low intensity and showed limited ontogenetic change; there was also no evidence of a dominance hierarchy among hatchlings by 50 weeks of age, when the frequency of agonistic interactions was lowest. Agonistic interactions between C. johnstoni and C. porosus at 40–50 weeks of age were mostly low level, with no real exclusion or dominance observed. However, smaller individuals of both species moved slowly out of the way when a larger individual of either species approached. When medium- or high-level interspecific interactions did occur, it was between similar-sized individuals, and each displayed species-specific behaviours that appeared difficult for contestants to interpret: there was no clear winner or loser. The nature of agonistic interactions between the two species suggests that dominance may be governed more strongly by size rather than by species-specific aggressiveness.

Movements and Home Ranges of Crocodylus johnstoni in the Lynd River, Queensland

1997 ◽  
Vol 24 (4) ◽  
pp. 379 ◽  
Author(s):  
A. D. Tucker ◽  
C. J. Limpus ◽  
H. I. McCallum ◽  
K. R. McDonald
Keyword(s):  
Field Trips ◽  
Home Ranges ◽  
Adult Males ◽  
Dominance Hierarchies ◽  
Breeding Sites ◽  
Crocodylus Johnstoni ◽  
Upstream Direction ◽  
A Minor ◽  
Australian Freshwater ◽  
Local Dominance

Movements of Australian freshwater crocodiles, Crocodylus johnstoni, were examined by a mark–recapture study spanning 20 years in the Lynd River, Queensland. After adjustment for detection bias, there was a minor upstream direction to movements. Seasonal changes of location were not evident from field trips taken only twice yearly. Annual movements averaged less than 1 km except for those of pubescent males, which appeared to be nomadic. Creche dispersal was randomly directed but associated with a threshold in mass/length ratio. On average, males were found further from previous capture sites than were females. Adults of both sexes moved shorter distances than did immature crocodiles with a clear reduction in movements occurring as mass/length ratios approached 0·17 kg per cm snout–vent length. Reduced movement at that general size ratio probably indicated the onset of territoriality associated with maturity. Females usually remained near breeding sites even in years when they did not breed. Nomadic tendencies of pubescent males are probably associated with unsuccessful attempts at entering local dominance hierarchies. Linear home ranges were estimated to be 1·5–1·9 km for immature animals, 1·2 km for pubescent females, 30·3 km for pubescent males, 0·6 km for mature females and 1·6 km for adult males.

Proctocaecum blairi sp. nov. (Digenea, Cryptogonimidae) from the freshwater crocodile, Crocodylus johnstoni, in Northern Territory, Australia

2010 ◽  
Vol 55 (3) ◽  
Author(s):  
Vasyl Tkach ◽  
Scott Snyder
Keyword(s):  
New Species ◽  
Relative Length ◽  
Anterior Testis ◽  
Northern Territory ◽  
The Body ◽  
Body Proportions ◽  
Diagnostic Features ◽  
Crocodylus Johnstoni ◽  
Freshwater Crocodile ◽  
Australian Freshwater

AbstractProctocaecum blairi sp. nov. is described from specimens found in the intestine of an Australian freshwater crocodile, Crocodylus johnstoni, from Northern Territory, Australia. The most important diagnostic features of the new species are the body proportions and size, the position of the pharynx (relative length of the prepharynx and oesophagus), the relative length and position of the vitelline fields, and the number, shape and size of the circumoral spines. The new species is morphologically most similar to Proctocaecum atae, P. elongatum, P. crocodili, P. gairhei and Acanthostomum slusarskii. It differs from all of these species in having a much longer prepharynx, and differs from both P. atae and P. crocodili in having a much longer body and posteriorly situated vitelline fields. Proctocaecum blairi sp. nov. differs from P. elongatum in having a shorter body, a greater forebody to hindbody ratio, a much smaller ventral sucker, and a higher number of circumoral spines (23 vs 21 in P. elongatum). The new species differs from P. gairhei in possessing a much larger body length:width ratio and an ovary separated from the anterior testis by a seminal receptacle. Acanthostomum slusarskii lacks a gonotyl and has fewer circumoral spines than the new species. Proctocaecum blairi sp. nov. is the third species of Proctocaecum and the fourth cryptogonimid species known from crocodiles in Australia.

scholarly journals Molecular identification of three novel herpesviruses found in Australian farmed saltwater crocodiles (Crocodylus porosus) and Australian captive freshwater crocodiles (Crocodylus johnstoni)

2015 ◽  
Vol 181 (3-4) ◽  
pp. 183-189 ◽  
Author(s):  
Timothy H. Hyndman ◽  
Catherine M. Shilton ◽  
James F.X. Wellehan ◽  
Steven Davis ◽  
Sally R. Isberg ◽  
...  
Keyword(s):  
Molecular Identification ◽  
Crocodylus Johnstoni ◽  
Crocodylus Porosus

Ascaridoid nematodes of amphibians and reptiles: Goezia

1978 ◽  
Vol 52 (1) ◽  
pp. 91-98 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
New Species ◽  
Freshwater Fish ◽  
East Coast ◽  
South American ◽  
Sea Snakes ◽  
Crocodylus Porosus ◽  
Cape York ◽  
Host Relationships ◽  
Australian Freshwater ◽  
A New Species

ABSTRACTA new species in the genus Goezia is described from aquatic reptiles of the northern shores of Australia, west of Cape York Peninsula. It was collected from Crocodylus porosus, from a file snake (Achrochordus granulatus), and from sea snakes (Lapemis hardwickii, Enhydrina schistosa, Hydrophis elegans, and H. caerulescens). The new species is compared with G. fluviatilis from Australian freshwater fish, with G. minuta from marine fish of the east coast of North America, and with G. spinulosa and G. intermedia from South American freshwater fish. The host-relationships of the genus are discussed.

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