Any distinction between this open mark and an ogonek⟨◌̨⟩ is idiosyncratic. Both graphically and semantically, the Teuthonista open mark is very similar to the obsolete IPA convention of using the ogonek for the same meaning, and some Teuthonista documents simply use an ogonek, as do many electronic Teuthonista fonts. However, there are printed sources where the Teuthonista open mark is visually distinct from the ogonek used in Polish place names, and more closely resembles a turned apostrophe or even a Greek subscript iota; the ogonek, on the other hand, when it is used for nasalization in Teuthonista sources, may take an angular shape like ∠, but there are also Teuthonista sources where the open mark has this angular shape. This may simply be a matter of using different typefaces for Teuthonista phonetic notation and for the surrounding text.
The ogonek also has a graphic variant, accessible in fonts like Gentium, that resembles a retroflex tail (◌̢) and is essentially identical to the iota-like variant of the open mark.
