Rankinia

Rankinia diemensis CLOQUET, 1816

Mountain Heath Dragon / Mountain Dragon

CLEMANN, N. (2001): Mountain dragons (Tympanocryptis diemensis) of Victoria: a complex issue. – Monitor, 11 (2): 6-8.

COGGER, H.G. (2014): Rankinia diemensis (Gray, 1841) Mountain Dragon – In:  Reptiles and amphibians of Australia. 7th Ed. CSIRO Publishing.

GRAY, J.E. (1841): Description of some new species and four new genera of reptiles from Western Australia, discovered by John Gould, Esq. - Ann. Mag. Nat. Hist., (1) 7: 86-91.

KENT, D.S. (1987): Notes on the biology and osteology of Amphibolurus diemensis (Gray, 1841), the mountain dragon. – Vict. Nat., 104 (4), 101–104.

MELVILLE, J., HUTCHINSON, M., CLEMANN, M., ROBERTSON, P. & D. MICHAEL (2018): Rankinia diemensis. The IUCN Red List of Threatened Species 2018: e.T176219A83494457.

NG, J., CLEMANN, N., CHAPPLE, S.N.J. & J. MELVILLE (2014): Phylogeographic evidence links the threatened 'Grampians' Mountain Dragon (Rankinia diemensis Grampians) with Tasmanian populations: conservation implications in south-eastern Australia. – Cons. Gen.,15 (2): 363-373.

The importance of protecting genetic diversity within a species is increasingly being recognised by conservation management authorities. However, discrepancies in conservation policy between authorities, such as state versus national bodies, can have significant implications for species management when they cross state boundaries. We conducted a phylogeographic study of the south-eastern Australian lizard Rankinia diemensis to identify evolutionary significant units (ESUs), including the endangered population from the Grampians National Park in western Victoria. Phylogenetic analyses of two gene regions (mtDNA: ND2; nuclear: RAG1) revealed high levels of genetic divergence between populations, indicating isolation over long evolutionary time frames. Based on criteria of genetic divergence and isolation, R. diemensis contains at least two ESUs that require specific management. We found that R. diemensis from the Grampians are closely related to Tasmanian populations, but that the divergence between these regions is great enough (3.7 % mtDNA) that they should be considered separate ESUs. However, we believe the close evolutionary ties between these two regions needs to be taken into account; yet under current practises, conservation management of subspecific ESUs relies on statelevel efforts. We argue that another population that occurs on the Victorian coast also qualifies as an ESU and requires targeted conservation action. Rankinia diemensis provides a case-in-point of the discrepancy between the state-level approach of maintaining genetic variation within a species and the more conservative Commonwealth focus on conserving biodiversity at the species level.

STUART-SMITH, J.F., STUART-SMITH, R.D., SWAIN, R., & E. WAPSTRA (2008): Size dimorphism in Rankinia (Tympanocryptis) diemensis (family Agamidae): sex-specific patterns and geographic variation. – Biol. J. Linn. Soc., 94 (4): 699-709.

Sexual dimorphism has implications for a range of biological and ecological factors, and intersexual morphological differences within a species provide an ideal opportunity for investigating evolutionary influences on phenotypic variation. We investigated sexual size dimorphism (SSD) in an agamid species, Rankinia [Tympanocryptis] diemensis, to determine whether overall size and/or relative morphological trait size differences exist and whether geographic variation in size dimorphism occurs in this species. Relative morphological trait proportions included a range of head, limb, and inter-limb measurements. We found significant overall intersexual adult size differences; females were the larger sex across all sites but the degree of dimorphism between the sexes did not differ between sites. This female-biased size difference is atypical for agamid lizards, which are usually characterized by large male body size. In this species, large female-biased SSD appears to have evolved as a result of fecundity advantages. The size of relative morphological trait also differed significantly between the sexes, but in the opposite direction: relative head, tail, and limb sizes were significantly larger in males than females. This corresponds to patterns in trait size usually found in this taxonomic group, where male head and limb size is important in contest success such as male–male rivalry. There were site-specific morphological differences in hatchlings, including overall body size, tail, inter-limb, thigh, and hindlimb lengths; however, there were no sex-specific differences indicating the body size differences present in the adult form occur during ontogeny.

STUART-SMITH, J., SWAIN, R., STUART-SMITH, R.D. & E. WAPSTRA (2007): Is fecundity the ultimate cause of female-biased size dimorphism in a dragon lizard? - J. Zool. (London), 273 (3): 266-272.

Fecundity selection is one of the most influential underlying driving forces responsible for body size differences between the sexes of a species. Reproductive output is one of the most important aspects of an animal’s life-history strategy, and any trait that acts to improve this will be under strong selection. Body size is one potential trait that can influence fecundity and when a species exhibits femalebiased size dimorphism, fecundity provides an ideal starting point for understanding why dimorphism in body size exists. Female-biased sexual size dimorphism is uncommon in vertebrates, including lizards. To explore the relationship between female-biased size dimorphism and fecundity, we examined maternal size and clutch data collected over four years from a temperate-zone agamid, Rankinia (Tympanocryptis) diemensis. We measured the following descriptors of reproductive output: clutch size and mass, relative clutch mass (RCM), average egg mass and offspring size. We found a positive relationship between maternal size and clutch size and mass, but no relationship between maternal size and RCM, average egg mass or hatchling size, demonstrating that the relative reproductive output is not influenced by female size, and that the only way to increase reproductive output is for the female to attain a greater body size. There exists an overall strong relationship between maternal body size and fecundity, thereby providing a potential explanation as to why female size is under selection in this species.

STUART-SMITH, J., SWAIN, R., & E. WAPSTRA (2007): The role of body size in competition and mate choice in an agamid with female-biased size dimorphism. – Behaviour, 144 (9): 1087-1102.

Competition and mate choice are fundamentally important components of social systems. We investigated intra-sexual competition and inter-sexual competition (mate choice) in Rankinia diemensis, an agamid lizard with female-biased size dimorphism. We examined intra-sexual interactions during contests and mate choice in relation to body size for both males and females. In male–male competition trials, proportions of two display types differed depending on body size, with more tail flicks produced by bigger males, and more hand-waves displayed by smaller males. These behaviours hold particular biological significance for agamid lizards; tail-flicks convey aggressiveness and, therefore, dominance, while hand-waves often denote submissiveness. In female–female competition trials, a greater difference in body size between the two conspecifics resulted in the larger female directing more pushes towards the smaller female. This female competition may be important in the social system and could be involved in resource defence. We found no indication of size-based mate choice for males or females. This suggests mate preferences may not be based on body size in this species. This may be linked to female-biased size dimorphism in this species, but it also supports previous studies that have failed to demonstrate female choice in reptiles.

STUART-SMITH, J., SWAIN, R. & A. WELLING (2005): Reproductive ecology of the mountain dragon, Rankinia (Tympanocryptis) diemensis (Reptilia: Squamata: Agamidae) in Tasmania. – Pap. Proc. Roy. Soc. Tasm., 139: 23-28.

The mountain dragon, Rankinia (Tympanocryptis) diemensis (Gray, 1841), is the only member of the Agamidae in Tasmania. It occurs in some of the coldest regions occupied by any dragon in Australia, and is found in a variety of habitats ranging from coastal heath to alpine scrub. This paper examines the reproductive ecology of R. diemensis in the most southerly range of its distribution, providing baseline data on timing of reproductive events, reproductive cycles, nesting behaviour and ovipositioning, clutch characteristics and incubation conditions. Winter torpor lasts approximately seven months with males emerging in early September and spermatogenesis occurring from September-November. Females emerge later, with vitcllogenesis occurring from September-December. Gravid females may be found between October and January, but females are non-vitcllogenic from late December until the following season. The first clutch is typically laid from October-December, with a variable clutch size (2-11 eggs). Females store sperm and a second clutch may be laid five weeks after the first. Eggs incubated in artificial enclosures at low altitude hatched after 72-106 days, after experiencing an average daily temperature of l 9°-22°C, and a range of 5°-39°C.

zurück / back