Adinda Kurnia Putri

Halichoeres argus is a marine wrasse; reef-associated (https://www.fishbase.se/summary/Halichoeres-argus.html);. By the way, wrasses, which are found in the Indo-Pacific, frequent all coral reefs, so to speak. It is among them that Wrasses which perform cleaning services are encountred. Your observations lead to ask the following question: is the wrasse Halichoeres argus a cleaner fish? To answer this question, an exhaustive bibliographical research is necessary as well as a study of the stomach contents of this species statistically valid in time and in space.

Moreover, most wrasses are carnivorous predators and eat small crustaceans, snails and worms which would explain the presence of other free Crustaceans as Peltidium sp. (Crustacea, Copepoda, Harpacticoida) in the gut content of Halichoeres argus which would be a complement to the cleaning activity.

Not sure of genus, but order could be Isopoda.

It’s possible if the genus is one of Tylos sp ?

Pictures 1 and 3 are probably Isopoda.

But picture 2 shows a parasitic copepod.

Probably a female of Caligus centrodonti (?)

Its species name is related to its parasitism on the fish Pagellus centrodontus.

Sorry : ERRATUM

I think Figures 1 and 3 are not isopods because the segmentation is not compliant. They are actually also copepods, like Peltidium sp. or neighbors.

Brylinski Jean-michel so it is belonging to Harpacticoid copepods ?

Yes, Harpacticoid copepods.

About systematic, you have to consult WoRMS in internet.

"World Register of Marine Species"

I agree with Brylinski Jean-michel concerning picture 2 which shows a parasitic copepod belonging to Caligidae family and to Genus Caligus.

Following

Clarification:

I agree with Brylinski Dr Jean-michel concerning picture 2 which shows a parasitic copepod belonging to Caligidae family and to Genus Caligus.

However, neither cephalothorax shape (suborbicular with narrow frontal plates and rather small lunules in C. centrodonti), nor that of genital complex nor uropods correspond to those of the species centrodonti.

Oum Kalthoum Ben Hassine since it is found in a gut content of fish, can i only use the genus because it may be hard to identify to species as many of this copepod have its body broke and lost ?

Yes, of course, you can use the denomination Caligus sp. which implies that you have could not identify the species.

The presence of this copepod in the gut of fish is curious and unusual because it is an ectoparasite (external parasite) which, depending on the species, attaches to fish body or gills.

The fish that you have examined may be cleaners fish that feed on parasites attached on the body or on the gills of other fish. If not, some species of the genus Caligus, which normally attach to the body of their host fish, may momentarily abandon their host and swim again nearby (I myself had the opportunity to observe this behavior during experimentation). It is at this time that they are ingested by other fish.

Could you give me the name of the fish species from which you collect this parasitic copepod in its gut? In this case, I would have a better understanding.

Oum Kalthoum Ben Hassine I’m really sorry for the very late reply. I mostly found this copepod in the gut content of Halichoeres argus..not only Peltidium sp. but also anothwr type such as Phillipiponte sp. Is that possible ?

Adinda Kurnia Putri

Halichoeres argus is a marine wrasse; reef-associated (https://www.fishbase.se/summary/Halichoeres-argus.html);. By the way, wrasses, which are found in the Indo-Pacific, frequent all coral reefs, so to speak. It is among them that Wrasses which perform cleaning services are encountred. Your observations lead to ask the following question: is the wrasse Halichoeres argus a cleaner fish? To answer this question, an exhaustive bibliographical research is necessary as well as a study of the stomach contents of this species statistically valid in time and in space.

Moreover, most wrasses are carnivorous predators and eat small crustaceans, snails and worms which would explain the presence of other free Crustaceans as Peltidium sp. (Crustacea, Copepoda, Harpacticoida) in the gut content of Halichoeres argus which would be a complement to the cleaning activity.

The first picture is a parasitic copepod of the genus Caligus (Siphonostomatoida: Caligidae), species may be Caligus epidemicus, other pictures are not clear.

Yes 1st one solved. 2nd and 3rd one looks like Porcellidium species of family Porcellidiidae in Harpacticoida. Both are male like. You can find it in google images easily.

Sung Joon Song Thank you for your kind response. Gladly i've also state it as Porcellidium as well, i found it on an article. However, still i have a problem in identifiying Harpacticoid copepod. In case do you have some materials/ guideline book to Harpacticoid copepod could you please inform me ? thank you

Adinda Kurnia Putri

Thanks Adinda. Recently this family divided into 16 genera from one genus, Porcellidium. You can find most recent review paper in this site. Type Porcellidiidae and then you can find the paper Harris, Vernon A. (2014). If your can't I will send you. -Sung Joon

Sung Joon Song

Thankyou Mr Sung Joon , the article you've mentioned can be downloaded. Talking about Harpacticoidae do you know the genus / family of those attached pictures of Harpacticoid copepods. I found it hard to identify Harpacticoid copepods even into family because those are so quite similar. I am using Yamaji (1980) and Conway DVP (2012) but seem none of them listed in that books.

I think first one is calgus but l am not sure couse photo it's not clear

Unfortunately, it is not easy to identify the animals pictured without dissection or making slide preparation, even family.

Sung Joon Song so does it is fine to state those animals as only Harpacticoid Copepods since it also found in a gut content of fish ?