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A dragon a day keeps the blues away (maybe)

About the Author

Miranda Wade received her B.S. in Biological Science from Colorado State University and her dual PhD in Integrative Biology and Ecology, Evolutionary Biology, and Behavior from Michigan State University. During her time in the Meek Lab at MSU, her work consisted of using ‘omics to address various conservation questions in both a rare desert place facing land-use change and the molecular consequences of microplastics exposure in a model fish species. She is currently the Social Media Editor for the AGA and a PostDoc in the Sin Lab at the University of Hong Kong.

Since we are now officially in the Year of the Dragon, I’d like to highlight some JoH articles featuring science on some ‘dragons’.

Figure 1: The dragon millipede (right) compared to another species of millipede sharing the same habitat.

All the way from 1924, we have this description of a ‘dragon milliped(e)’ Hylomus draco from central China. The spines on the back of this millipede were thought to be evolutionary holdovers with no current-day utility. This species can be found throughout Southern China, Laos, Vietnam, and Northern Thailand. Not much was known about the evolutionary history of this family until some recent work used both nuclear and mitochondrial DNA to construct its phylogeny. As there is a great diversity of morphology found within Hylomus, it is no surprise that the species within the genus did not group together cleanly (i.e., Hylomus is non-monophyletic). (Note: Cook and Loomis make some racist comments in the article that should never have made it to the press, but alas much of the early 20th century in genetics featured racism and outright eugenics.)

Figure 2: A leafy seadragon looking fabulously dramatic. Photo courtesy of the Australian Museum

Here’s a 2016 article about the leafy seadragon (Figure 2), Phycodurus eques. This seadragon is very popular at aquariums due to its impressive camouflage. As a flagship species, the seadragon serves as a ‘face’ in marine conservation. The authors used microsatellites to characterize its genetic diversity (moderate to low) and differentiation (split between West and South Australia). However, a larger sample size is needed to fully capture the genetic diversity of the seadragon across its range. Key takeaways from this study were that maintaining genetic diversity by ensuring habitat connectivity is best for these seadragons.

Figure 3: Jacky Dragon juvenile. Photo by David Paul and Museums Victoria.

A 2019 article used Jacky Dragons Amphibolurus muricatus (Figure 3) as well as painted turtles and common snapping turtles to investigate covariance (i.e. as one variable changes the other does as well) between maternal egg-laying behavior and the sensitivity of their offspring to environmental conditions. As these three species all have temperature-dependent sex determination (TSD) but exhibit different behaviors related to this phenotype, they were good models for the effects of behavioral phenotypes on the sex ratio of offspring. This has important implications in looking back on the evolution of the trait itself as well as looking toward the future and determining the consequences of a changing climate on TSD species. If there was positive covariance between nesting behavior (such as the mother choosing to lay eggs in cooler vs warmer areas) and the sex ratio of the offspring, it would increase the efficacy of selection on the trait. However, no covariance was detected, so the evolution of these traits appears to be independent!


Happy Lunar/Chinese New Year!



  1. F. COOK, H. F. LOOMIS, A DRAGON MILLIPED IN CHINA: An Extreme Type, Showing That Evolution is Not Limited To Useful Characters,Journal of Heredity, Volume 15, Issue 2, February 1924, Pages 51–53,
  2. Ruttapon Srisonchai, Henrik Enghoff, Natdanai Likhitrakarn, Ekgachai Jeratthitikul, Parin Jirapatrasilp, Somsak Panha, Chirasak Sutcharit, Molecular phylogeny of dragon millipedes (Diplopoda: Polydesmida: Paradoxosomatidae) from mainland South-East Asia, with description of a new genus and species, Zoological Journal of the Linnean Society, 2023;, zlad164,
  3. Josefin Stiller, Nerida G. Wilson, Stephen Donnellan, Greg W. Rouse, The Leafy Seadragon, Phycodurus eques, a Flagship Species with Low But Structured Genetic Variability, Journal of Heredity, Volume 108, Issue 2, 1 March 2017, Pages 152–162,
  4. Fredric J Janzen, David M Delaney, Timothy S Mitchell, Daniel A Warner, Do Covariances Between Maternal Behavior and Embryonic Physiology Drive Sex-Ratio Evolution Under Environmental Sex Determination?, Journal of Heredity, Volume 110, Issue 4, June 2019, Pages 411–421,

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