The Jackknife Fish, Linnaeus and a drummer - 1001fishes project

This last couple of days I've kind of lost myself, I originally wanted to talk about the Jack Knife fish, but I painted a Spotted drum juvenile instead, because they are from the same Genus and their juveniles are really looking similar. With only one visible difference, that I will explain soon. And you may ask why I wanted that specific fish ? Well, there is two main reasons : first, I am in love with that species, they have a really beautiful way of swimming, secondly they have been described by the legendary Carolus Linnaeus ! Let's dive into the history of the 'father of modern taxonomy'.

Carl von Linné and the 10th Systema Naturae

Alexander Roslin - portrait of Carl von Linné

Linnaeus is a Swedish botanist, biologist and zoologist from the XVIIIth century. Famous for his use of the Binomial nomenclature Scientific classification in taxonomy, which is a way to classify and name species by the use of two terms. These terms comes from Latin roots, and this system have been created to simplify sentences long names of species. Keeping the long sentences for brief descriptions of the species characteristics, the 10th Systema Naturae is the first book to use consistently the binomial classification. Therefore it became the basis of Nomenclature Codes, which are the rulebooks of nomination and classification of species. For example the ICZN - International Code of Zoological Nomenclature stands for all animals descriptions.

If we look into the first volume, published in 1758, and specifically at the page 277, we can read :

If anyone is capable of reading and translate this, first bravo and then could you help me in my future research ? <3

The Jack knife fish name's evolution

So if I can't understand the fish description, I can read that his name was Chaetodon lancelolatus. And of course it have seen many changes with time : Bloch listed him as Eques americanus in 1793, and Cuvier Eques balteatus in 1829. The valid scientific name today is : Equetus from Latin root eques = knight, lanceolatus lanceola = small spear, as he have a general spear shape.

Our little knight is a solitary one, which tend to swim in circles around his own lands, leaving only by night to go hunting. He is feeding on small crustaceans, worms, snails and smaller fishes. But he is never far away from a hideout. E.lineolatus is also a 'musician', he can use some specific muscles to create some drum rolls by vibrating his swim bladder ! We can say that he is the knigh, the hunter and the troubadour the whole Middle Ages troop by himself !

How to spot the distinction between two slightly different Equetus

The bottom watercolor I show you is an E.lanceolatus, and the top one is E.punctatus. When juvenile, they are really close looking, but the adult forms are really different. To distinguish them you have to look at their snout : E.lanceolatus have a single vertical black line, whereas E.punctatus have... a single black point !

Equetus lanceolatus - Collection Georges Declerq

We can easily find the Jack knife fish in Caribbean areas, from the Bermudas to south Basil, in reefs and sand or mud areas between 1 and 60m deep. He have a good value in the aquariology market, with a 20cm adult size, I saw prices up to 200USD online, or 100GBP. Some private companies have successfully breed them in captivity, releasing pressure on wild populations, and bringing down the fish price. So he is under Least Concern by IUCN red list and doesn't get any specific protection. We will eventually come to the advantages of captive breeding on wild populations, overall fish treatment, and survival in captivity.

Thats all for me, I hope you enjoyed as much as I enjoy exploring natural history and fishes biology. I would love to have some feedback from more experienced writers and/or watercolorist, to keep improving ! I find myself struggling to find any kind of feedback, and I think it's the core of developing new skills. So any comment or criticism is welcome !

Take care,

Arnaudt.

With the help of my lovely sister <3

Bibliography :

• Wikipedia contributors. "Carl Linnaeus." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 18 Oct. 2019. Web. 9 Nov. 2019.

• SUTOUR Jean-Michel, GOYEAU Alain, PROUZET Anne in : DORIS, 27/12/2015 : Equetus lanceolatus (Linnaeus, 1758), https://doris.ffessm.fr/ref/specie/983

• IUCN redlist : https://www.iucnredlist.org/species/46104959/49221561

• WORMS names database : http://www.marinespecies.org/aphia.php?p=taxdetails&id=159315#sources

• 10th Systema Naturae p277 : https://biodiversitylibrary.org/page/727188

• Wikipedia contributors. "10th edition of Systema Naturae." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 19 Oct. 2019. Web. 9 Nov. 2019.

• Wikipedia contributors. "Nomenclature codes." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 19 Oct. 2019. Web. 9 Nov. 2019.

• Captive bred E.lanceolatus : https://www.proaquatix.com/portfolio/jack-knives/ found on https://reefbuilders.com/2015/06/22/proaquatix-news-coming/#