The jigsaw: putting together the Bloody Perchlet puzzle
Museum collections provide a treasure trove of undiscovered species, and in this case the newly discovered and beautiful Bloody Perchlet, Plectranthias cruentus, was a jigsaw puzzle put together from old and new.
For over 100 years, a little brown fish has been sitting, tucked away on a high shelf in a dark corner on level three of a five-storey collection storage building, called the Spirit House. This small brown fish is a newly discovered species called Plectranthias cruentus, with the Common name: Bloody Perchlet. This Bloody Perchlet was collected at Lord Howe Island in 1913 and donated to the Australian Museum by Perceval R. Pedley, Esquire. Fast forward 90 years and three more Bloody Perchlets were collected together at a depth of 86–89 m near Ball’s Pyramid in the Lord Howe Island Marine Park, as part of the 2003 NORFANZ survey (a joint Australian and New Zealand research voyage, where scientists explored deep sea habitats and biodiversity of the Tasman Sea).
Plectranthias cruentus, AMS I.12854, 43.0 mm SL, Australia, Lord Howe Island, P.R. Pedley, 1913.
Image: Amanda Hay© Australian Museum
It was not until 2019 that scientists Anthony Gill and Clive Roberts had looked at enough Perchlet specimens – hundreds in total, from around the globe – that they were able to establish the specimens as a new species, unlike any other species they had seen before.
Perchlets are often found in deep water reefs, beyond the range of conventional scuba diving, and many are known only from a few trawl specimens. What makes the Bloody Perchlet different from all other species is: the combination of a dorsal fin with 10 spines and 16 or 17 soft rays; the fifth or sixth dorsal spine being the longest (as opposed to the third, on other species); some pectoral fin rays branched; and, inconspicuous serrations on the interopercle (the part of the bony structure that covers the gills).
X-ray of holotype, Plectranthias cruentus (AMS I.42725-007). X-rays are used to study the skeleton of a fish without damaging the specimen in any way, different skeletal features can help identify and separate species.
Image: Jeremy Barker & Carl Struthers© Te Papa
Although the appearance of the Bloody Perchlet is that of a small brown fish in preservation, in life it is a vibrantly coloured fish. The body is bright orange/red, becoming yellow-orange ventrally, and crossed by narrow, red-edged pink oblique bars. So why name this fish a Bloody Perchlet, you may ask? Well, the etymology is from the Latin cruor, meaning stained or spotted with blood, and alludes to the bright red markings in life.
Plectranthias cruentus, AMS I. 42725-007, 57.3 mm SL, freshly dead holotype, off Ball’s Pyramid, Lord Howe Island, Australia.
Image: Robin McPhee/Kerryn Parkinson© 2003 NORFANZ Voyage
As the Bloody Perchlet illustrates, new species are not always discovered from newly collected specimens as you may expect, but are discovered in Museum collections. Becoming more important through time as the climate changes and our environments face more stresses, museum collections will become increasingly important as the libraries of our planet’s biodiversity.
Amanda Hay, Ichthyology Collection Manager, Australian Museum Research Institute
Dr Anthony Gill, Ichthyology Research Associate, Australian Museum Research Institute; Natural History Curator - Macleay Collections, Chau Chak Wing Museum, University of Sydney.
More information:
Gill, A.C. & Roberts, C.D., 2020. Plectranthias cruentus, a new species of anthiadine perchlet (Teleostei: Serranidae) from the Lord Howe Rise, Tasman Sea. Zootaxa 4750 (4): 560–566. https://www.biotaxa.org/Zootaxa/article/view/zootaxa.4750.4.6
