In my post of 2 May 2013, I considered what had happened to the name of a beautiful species of rat that occurs in Hong Kong. For decades it was known as Huang’s Rat, Rattus huang but it came to be lumped into what was Rattus fulvescens and is now Niviventer fulvescens.
The genus Niviventer was erected by Joe Truesdell Marshall (1918-205) for a group of Asian rodents previously included in Rattus. They can be distinguished by their white belly (niveus—snowy white in Latin).
Generous to a fault, I bought my wife a copy of a volume in that remarkable series The Handbook of Mammals of the World. It is the volume, Rodents II, which covers, as superbly as ever, with information up-to-date at the time of going to press, rats and mice. Having been granted access I found that Niviventer huang has been resurrected as a result of phylogenetic research in China and has been given the common name of South China White-bellied Rat.
As has been said many times, the rats and mice of China are confusing to say the least. Researchers find that specimens have been wrongly identified in museums throughout the world and one only has to look at maps of where specimens have been collected from to realise that whole regions have been missed.
Modern phylogenetics are way above my pay grade and I am not entirely sympathetic to drawing conclusions on whether a species thus defined constitutes a ‘good’ biological species reproductively isolated (or with very limited gene flow) from its near relative. I have looked up the references given in the Handbook. The main work seems to have been done with two genes, one mitochondrial and one nuclear on, in some cases, very small samples. Whether that number of genes and that number of individual samples, together with the statistical methods used, would satisfy all phylogeneticists I do not know. The authors, most of whom are based in Beijing, do make the point that more work is needed on N. huang since, on their reckoning, it may comprise more than one species.
More recently than the press date of the book, another group, based in Kunming, also examined niviventers using one mitochondrial and three nuclear genes. They found less strong evidence for the existence of N. huang as a species separate from N. fulvescens.
Are there any morphological differences between the two species? The Beijing group found that N. huang could be differentiated from N. fulvescens by head and body length.
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| I have combined the maps in the Handbook to show the current views on the distribution of the two species |
Clearly, much more work with an extensive sampling of niviventers right across the distribution of these two and other species in China is needed but for the time being at least Huang’s Rat or Niviventer is back on the list of Hong Kong mammals, while N. fulvescens is out.
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| The only recent photograph I have been able to find of Niviventer huang is this one from a website in Russian which Google Translate says in the Russian-Vietnamese Research and Technology Centre |
Wilson DE, Lacher TE, Mittermeier RA (editors). 2017. Handbook of Mammals of the World. Volume 7. Rodents II. Barcelona: Lynx Edicions.
Lu L, Ge D, Chesters D, Ho SYW, Ma Y, Li G, Wen Z, Wu Y, Wang J, Xia L, Liu J, Guo T, Zhang X, Zhu C, Yang Q, Liu Q. 2015. Molecular phylogeny and the underestimated species diversity of the endemic white-bellied rat (Rodentia: Muridae: Niviventer) in Southeast Asia and China. Zoologica Scripta 44 475-494. doi:10.1111/zsc.12117
Zhang B, He K, Wan T, Chen P, Sun G, Liu S, Nguyen TS, Lin L, Jiang X. 2016. Multi-locus phylogeny using topotype specimens sheds light on the systematics of Niviventer (Rodentia, Muridae) in China. BMC Evolutionary Biology16, 261-272. doi 10.1186/s12862-016-0832-8
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