The prawn that lost its name, twice

26 November 2026

Part 16 of 18 · A history of the giant freshwater prawn

In 1869 or 1870, near Andai in New Guinea, the naturalist C. B. H. von Rosenberg collected a female giant freshwater prawn carrying eggs. In 1879, the zoologist J. G. de Man described a species from her and named it after the collector: Palaemon rosenbergii.[1]

She came from the eastern side of the Huxley line (Part 13). The name the world’s prawn farms use began with a prawn from Australia’s side of the family.

For more than a century, the prawns on both sides of the line shared that name. Other names came and went: in 1902, Schenkel described Palaemon spinipes from North Sulawesi, and in 1925 a prawn from Java was named dacqueti, but they were treated as one species, or at most as two forms of it.[1][2] Then the genetics split them, and in 2007 the taxonomists Daisy Wowor and Peter Ng separated them into two species.[1]

The rules of zoological naming then produced an awkward result. The name rosenbergii belonged to the eastern prawn, the New Guinea female’s kind. The farmed prawn, with fifty years of research and hundreds of thousands of tonnes behind it, would have had to become dacqueti.

So in 2008, Wowor and Ng asked the International Commission on Zoological Nomenclature for an exception: keep rosenbergii for the farmed prawn, by making a male from Java its new reference specimen. And they gave the eastern prawn a name of its own, Macrobrachium wallacei, after Alfred Russel Wallace, from a male caught in the Laloki River near Port Moresby.[3] In 2010, the Commission agreed.[4] Wallace had a prawn.

He kept it for three years. In 2011, Ng and Wowor found that Schenkel’s name, spinipes, which they had believed unusable, was available after all. In zoology, the oldest available name wins. The eastern prawn became Macrobrachium spinipes, and wallacei became a synonym.[2] Australia’s prawn had lost its name twice: first to the farmed prawn, then to a specimen described from Sulawesi a century earlier.

So which name is right? Both, for different prawns. Macrobrachium rosenbergii is the farmed prawn of South and South-East Asia. Macrobrachium spinipes is the eastern species of Australia, New Guinea, eastern Indonesia and the Philippines, and the name Australia’s official species lists accept.[5] The older name is the one most people know, and most of the literature uses it. Up close, the two differ in the base of the rostrum, the spines on the legs, a small plate under the thorax and their colours in life.[1] The aquarium trade has a quicker sign: in spinipes, the inner antennae are bright blue.[6] Even the line is a rule of thumb. In 2013, spinipes turned up in Taiwan.[7]

Is Australia’s prawn the smaller one? Nothing in the record says so. In the museum material behind the 2007 revision, the largest eastern male had a head-shell 104 millimetres long; the largest western male, 86.7.[1] What the native prawn lacks is the farmed prawn’s decades of domestication and selection. Australia’s hatcheries, working from wild spinipes, have had to adapt the farmed prawn’s methods rather than copy them (Part 14 and Part 15).[8]

Sixteen parts in, the prawn has a history, a line, a pecking order, a night shift and, finally, a name. It has been a more diverse and more interesting journey than even I expected.

What it still lacks is an answer to the two questions this series keeps coming back to: how one prawn slows another’s growth, and what tells a male when to stop growing (Part 6, Part 10). Building a research plan to answer them is what we spent much of our time on in CSIRO’s Innovate to Grow programme.

Sources

1. Wowor, D., Ng, P. K. L. (2007), The giant freshwater prawns of the Macrobrachium rosenbergii species group. The type from Andai, New Guinea (1869–70); the revision into two species; how to tell them apart; museum material and sizes. nhm.org
2. Ng, P. K. L., Wowor, D. (2011), On the nomenclature of Palaemon spinipes Schenkel, 1902. Zootaxa 2904: 66–68. Earlier names; spinipes available; wallacei a synonym. doi.org
3. Wowor, D., Ng, P. K. L. (2008), Case 3428: Palaemon rosenbergii De Man, 1879: proposed conservation of usage by designation of a neotype. Bulletin of Zoological Nomenclature 65(4): 288–292. The Java neotype; wallacei from the Laloki River. archive.org
4. ICZN (2010), Opinion 2253 (Case 3428). Bulletin of Zoological Nomenclature 67(3): 258–260. doi.org
5. Australian Faunal Directory, Giant river prawn; Atlas of Living Australia, Macrobrachium spinipes (accepted name). biodiversity.org.au · ala.org.au
6. Aquarium Glaser (April 2025), Macrobrachium spinipes (aquarium trade source). aquariumglaser.de
7. Shy, J.-Y., Wowor, D., Ng, P. K. L. (2013), A new record of the giant freshwater prawn, Macrobrachium spinipes, from Taiwan. Zootaxa 3734: 45–55. doi.org
8. Lober, M. (2015), Investigation of the aquaculture potential of an Australian freshwater prawn. MSc thesis, James Cook University. Wild broodstock; a breeding season of November to March in tropical Queensland. doi.org

Part 16 of 18 · A history of the giant freshwater prawn · Previous: Part 15, Twenty prawns to two hundred thousand · Next: Part 17 (coming soon; see the series) · SHRMP.bio’s strategy behind it: shrmp.bio/strategy.html