rexsa experimental gismu

x1 is a dinosaur [specific: only clade Dinosauria] of type x2 living in era x3.

A gismu version of dinsauru; contrast with dinso; ignoring connotations relevant to modern birds, the set of rexsa is a strict and nonempty subset of the set of dinso. Includes modern birds; there is no connotation to the contrary in general. Proposed short rafsi: -rex-. Preferred to reksa (for the sake of short rafsi and etymology). See also: ketslau.

In notes:

dinso
x1 is a 'dinosaur' [very general: any ancient quasi-reptilian vertebrate or, possibly but probably not, modern bird] of type x2 living in era x3.
ikfiio
x1 is a icthyosaur [member of order Ichthyosauria] of subtaxon/type/genus/species/variety/breed x2.
plesiio
x1 is a plesiosaur [member of order Plesiosauria] of subtaxon/type/genus/species/variety/breed x2.