Plesiastraea proximans

Author: Andrew Baird

Species: Plesiastraea proximans Dennant, 1904

The use of types in taxonomy does present some problems. For example, in many older works the catalogue number of the specimen on which the species description was based is not listed, and in some situations it is not even clear which museum the specimen was deposited in. Consequently, there is often some detective work to determine in which institution a specimen is located. Once the institution has been located, you then have to find the specimen, which might be stored under the name of the nominal species, or perhaps a later synonym. In many museums, the type material is stored separately, but in others the specimens are stored alphabetically or in collections based on the expeditions or the collector. Some types go missing, having been lent out and not returned, some are misplaced and some are destroyed. For example, many of Forskal’s types were destroyed when the British shelled Copenhagen during the Napoleonic Wars. The International Code of Zoological Nomenclature offers solutions to most of the potential problems with types. However, when a specimen goes missing at what point do you declare it lost and designate a neotype? What happens to the neotype if the original type material turns up? Below, I describe our attempts to locate the type of Plesiastraea proximans Dennant, 1904.

Plesiastraea proximans was described by Dennant (1904) from a single 2 cm long sample dredged from 22 fathoms (approximately 40 m) in St Vincent’s Gulf in South Australia. Dennant does not mention where he deposited the type nor does he give a catalogue number, although he did provide a sketch of the specimen (Fig. 1). Given that the description was published in the Transactions and Proceedings of the Royal Society of South Australia the logical place to start looking was the South Australian Museum (SAMA). In October 2021, I made a visit to SAMA to try to find the type with the help of curators Andrea Crowther and Shirley Sorokin. We found the types of two of the other species described in Dennant (1904) but not the type of P. proximans.

Wijsman-Best (1977) synonymised P. proximans with Plesiastrea versipora (Lamark 1816). However, she also states that she could not trace the type, “anywhere in the Southern Australia museums (Melbourne-Adelaide)”. In the course of our research we also came across a publication (Stranks 1993) suggesting that all Dennant’s scleractinian samples should be in the National Museum of Victoria (NMV), however, Stranks (1993) also stated that the holotype of P. proximans was missing. We contacted the curator of NMV who confirmed that the specimen could not be located at the NMV.

Figure 1. The holotype of Plesiastrea proximans, figured in Dennant (1904).

What do we make of all this often conflicting information? On the balance of probabilities, I suspect the specimen should be at SAMA with the other types described by Dennant (1904) but has subsequently gone missing, either lent out and not returned or perhaps sitting quietly in an obscure drawer in the museum. It would be very easy to misplace a 2 cm long piece of coral. Either way it probably makes sense to accept that the type is lost and designate a neotype. However, a neotype should ideally be collected from as close as possible to the original collection site, which means at a depth of 40 m in St Vincent’s Gulf, which I suspect is not going to happen any time soon.

We thank David Juszkiewicz for comments on the text and the curators of the NMV, Melanie Mackenzie and Chris Rowley, for double checking their catalogue.

Literature cited

Dennant, J. 1904. Recent corals from the South Australian and Victorian coasts. Transactions and Proceedings of the Royal Society of South Australia 28:1-11, pls. 11-12.

Stranks, T. N. 1993. Catalogue of Recent Cnidaria type specimens in the Museum of Victoria. Pages 1-26, with two page addendum  Occasional Papers from the Museum of Victoria 6.

Wijsman-Best, M. 1977. Indo-Pacific coral species belonging to the subfamily Montastreinae Vaughan and Wells, 1943 (Scleractinea-Coelenterata) Part I. The genera Montastrea and Plesiastrea. Zoologische mededeelingen 52:81-97.

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