Helping molecular identification!

The team just published a new study on an exclusively antarctic genus, the Trematomus. The genus contains 14 species, very abundant in the Southern Ocean, living different ecological niches. This is why it is essential to study this genus to better understand the antarctic ecosystem.

Scientists working on this group are hindered by identifcation problems. The 14 Trematomus species are very similar morphologically and a few caracters can distinguish one species from another one. In the case of damaged specimens or larvae, the identification is particularly difficult. In fact, larvae of teleosts are identified under a microscope by counting pigmented points.

Draws of two species of larvae belonging to genus Trematomus. On the left, Trematomus loennbergii and on the right Trematomus lepidorhinus, issue from  A. Kellermann.

In this context, barcode approach is a good way to avoid identification problem.

The aim of this work is to test if barcoding is a reliable method to identify Trematomus species. We have compared the identification obtained with the COI to the identification made by morphologists specialized on this group.

Results obtained by the COI and those from specialists of the group are congruent.

The barcode using COI is thus a promising tool of identification for the species of the genus Trematomus. The biggest novelty is that barcode provides a reliable tool to larvae and stomach contents.

Individuals identified as Pagothenia borchgrevinki coming from the stomach content of a Gymnodraco victori.

To learn more about it see Lautrédou et al., 2010[1].