Balanoglossus is connecting link between non-chordates & chordates.
Balanoglossus is connecting link between non-chordates & chordates.
Balanoglossus is called a connecting link because it shows some characters of non-chordates and some characters of chordates.
Chordate-like characters:
- Pharyngeal gill slits are present.
- A dorsal, hollow (tubular) nerve cord is present in the collar region.
Non-chordate characters:
- A true notochord is absent; there is only a short structure in the proboscis (buccal diverticulum), which was once thought to be a notochord.
- It also has a ventral nerve cord, and its worm-like body resembles non-chordates.
Because it has features of both groups, Balanoglossus (Hemichordata) is considered a connecting link between non-chordates and chordates.