In this next piece I am going to look at the names that have proliferated around the Murray River Turtle (Emydura macquarii) and its near relatives. This particular Australian turtle has proven very difficult to establish a decent nomenclature for with many names proliferated over the years. To the point I was recently asked when the name Emydura signata was used “how many times do we have to sink it” sometimes I do wonder that.
For many years the understanding of the relationships in Australian turtles was at best poorly known, but more accurately was a bunch of basket cases. For both living and fossil species Emydura was one of the basket cases. Anything that was not a long-neck (Chelodina) was basically assumed to be an Emydura. Nearly every Australian Chelid fossil that could be identified as a short neck has at some time been in this genus. Every river and color morph of the genus was its own species. This is saying something in Australia as the turtles there are rather grey to black in color with little else in the way of color. Only real exception to this is the Painted Turtle (Emydura subglobosa) and the members of Myuchelys.
Nomenclature is not science, taxonomy is science and there is a difference. So to truly understand and appreciate a nomenclatural problem you do have to go over its entire history. So like in the previous piece I wrote on Chelodina, we need to visit that history.
The first time the species was named was as Emys macquarii by Georges Cuvier in 1829 however this name is seen as a nomen nudum under the ICZN Code, so it is the second time it was named, as Chelys (Hydraspis) macquarii, which stands by John Edward Gray in 1830. Just one year later in 1831 Gray again named the species as Hydraspis macquarrii, this one may have been what in nomenclature is referred to as lapsus pro, or in error, but we cannot be sure. Next in 1835 it was the turn of André Marie Constant Duméril and Gabriel Bibron to try, they called it Platemys macquaria, again it is possible this was an error but it is not possible to know.
In 1836 Carlo Luciano Bonaparte named the genus Emydura and it could be hoped that at least the generic placement of this species may have stabilized at this point, not at all. Many people place the name Emydura australis in the list at this point, described by John Edward Gray in 1841. The holotype of Emydura australis is actually what we would currently call the Red-faced Turtle, Emydura victoriae, a potential nomenclatural issue for the future. Up to this point it has actually been fairly straight forward. But it was about to take many twists and turns.
Throughout the 1870’s John Edward Gray got very prolific coining the names Chelymys krefftii, Euchelymys sulcifera, Chelymys victoriae marmorata and Chelymys victoriae sulcata. It makes one wonder how many times you can name the same species. Other names to come along were Emydura signata by Ernst Ahl in 1932; Emydura canni by Eric Worrell in 1970; then Chelymys cooki, Chelymys johncanni, Chelymys windorah and Tropicochelymys insularis by Richard Wells and Ross Wellington in 1985. The proliferation of names for this species continued with Emydura macquarii binjing, Emydura macquarii dharra, Emydura macquarii gunabarra and Emydura macquarii dharuk by John Cann in 1998. Lastly, John Cann, Bill McCord and Joseph-Uoni named Emydura macquarii emmotti and Emydura macquarii nigra.
This major list of names is in the end all for a single species, Emydura macquarii. However it is correct to point out that at different times it has been considered to be more than one species. Throughout the period of the 1970’s to the 1990’s Emydura macquarii, Emydura krefftii and Emydura signata were widely recognized as separate species, with no evidence to demonstrate that actually existing. However from the 1990’s on it became more and more clear that this was in fact a wide ranging single species. Starting with the allozyme work of Arthur Georges and Mark Adams followed by molecular analysis, and better morphological work. During this period it was also discovered that there were a number of populations of Emydura in coastal rivers in New South Wales, reportedly all the way to Sydney. The latter is however an introduced population which is largely made up of released Krefft’s and Macquarie Turtles. The Hunter River is the most southerly natural population on the NSW coast.
The next step in sorting this massive set of names out was how they were distributed, which ones were valid and getting a sensible taxonomy for this species complex. This was initially done by Hal Cogger and eventually Arthur Georges and I completed it. It was clear that despite all being the same species 4 highly distinctive populations could be seen; Macquarie, Coastal Queensland, Cooper Creek and Fraser Island. It was also necessary to determine valid names and a number of them were declared nomen nudem by either Hal Cogger or by John Iverson, myself and Arthur Georges across a number of publications.
The last thing was to determine the oldest available name for the 4 populations to be recognized and these were as follows:
Macquarie River Turtle Emydura macquarii macquarii (Gray, 1830)
Krefft’s Turtle Emydura macquarii krefftii (Gray, 1871)
Cooper Creek Turtle Emydura macquarii emmotti Cann, McCord, and Joseph-Ouni, 2003
Fraser Island Short-necked Turtle Emydura macquarii nigra McCord, Cann, and Joseph-Ouni 2003
All the other names listed above are either nomen nudum or nomen novum, hence unavailable or invalid. I would refer readers to the most comprehensive checklist for living turtles; the IUCN Checklist in this you can see the full synonymy with explanations and full references.