Question

One of the following is connecting link between chordates and non chordates.

• A. Peripatus
• B. Neopilina
• C. Balanoglossus
• D. Tachyglossus

Answer 1

Answer: (C)

Balanoglossus

Balanoglossus is an ocean-dwelling acorn worm (Enteropneusta) genus of great zoological interest because, being a Hemichordate, it is an "evolutionary link" between invertebrates and vertebrates. Balanoglossus is a deuterostome and resembles the Ascidians or sea squirts, in that it possesses branchial openings, or "gill slits". It has notochord in the upper part of the body and has no nerve chord. It does have a stomochord, however, which is gut chord within the collar. They are the connection link between chordates and non chordates. Thus, option C is correct. Peripatus is an invertebrate, said to be a living fossil, because the living members appear similar to fossil species as much as 570 million years old. They are not the connection link between chordates and non chordates. Thus, option A is incorrect.
Neopilina is a highly derived genus of modern monoplacophoran. Some molecular results show that they fall within the polyplacophoran clade, although these have been called into question. They are not the connection link between chordates and non chordates. Thus, option B is incorrect. The short-beaked echidna (Tachyglossus aculeatus) is one of four living species of echidna and the only member of the genus Tachyglossus. The short-beaked echidna is covered in fur and spines and has a distinctive snout and a specialized tongue which it uses to catch its prey at a great speed. They are not the connection link between chordates and non chordates. Thus, option D is incorrect.