Macrorhynchia ambigua Watson, 2000

This species may be mistaken for Macrorhynchia phoenicia (Busk, 1852). Reliable differences between the two species are:

1.) The intrathecal septum of M. ambigua is much wider in lateral view and more wedge-shaped than that of M. phoenicia.

2) The mesial nematotheca of M. ambigua is shorter than that of M. phoenicia and is completely adnate to the abcauline wall of the hydrotheca.

3) The mature phylactocarp differs significantly from that of M. phoenicia and

4) Mature colonies of M. ambigua are much smaller and of paler brown colour than those of M. phoenicia.