'glass-lizard-related' is a Modern English compound formed from 'glass-lizard' (the common name for certain legless lizards) plus the adjective-forming element 'related' (from the verb 'relate').

'glass-lizard' itself is a compound of 'glass' + 'lizard' coined in English to describe a lizard whose brittle tail can break off (an image likened to glass); 'related' comes from Old French/Latin roots ('relater' < Latin 'referre'/'relatus') and here is attached to form an adjective meaning 'having a relation to'. The combined compound arose in Modern English by straightforward compounding.

Initially it simply denoted something pertaining to a 'glass-lizard'; over time the construction has been used productively to describe any attribute, study, or context associated with glass lizards, with no major semantic shift.