The predominant brachiopods during Cambrian times, the linguliforms are distinguishable by their organophospate shell. A famous example still extant is Lingula, which is discussed in more detail on the modern forms page. The linguliforms are thought to be more closely related to bryozoans and phoronids than they are to other brachiopods. Apparently, species of this subphylum have not changed much since the end of the Ordovician, about 440 million years ago. Some of the diverse forms of linguliform brachiopods can be seen below.
Lingula davisi, a Cambrian Linguliform.
Compare with living Lingula.