Cryptospores are microscopic fossilized spores produced by embryophytes (land plants). They first appear in the fossil record during the middle of the Cambrian period, as the oldest fossil evidence for the colonization of land by plants. A similar (though broader) category is miospores, a term generally used for spores smaller than 200 μm. Both cryptospores and miospores are types of palynomorphs.
Cryptospores are microscopic fossilized spores produced by embryophytes (land plants). They first appear in the fossil record during the middle of the Cambrian period, as the oldest fossil evidence for the colonization of land by plants. A similar (though broader) category is miospores, a term generally used for spores smaller than 200 μm. Both cryptospores and miospores are types of palynomorphs.
Cryptospores, which occur as permanent tetrads, dyads, or hilate monads, sometimes with additional wall envelopes, dominated fossil assemblages for approximately 60 million years, first appearing around 470 million years ago during the Ordovician Period. They underwent rapid diversification during what Jane Gray (1993) called the Eoembryophytic epoch, but experienced an abrupt decline in diversity and abundance around 410 Ma during the latest Lochkovian (Early Devonian), with only a few forms persisting into the Emsian period. In contrast, trilete monads began diversifying around 430 Ma in the latter Silurian Period and eventually became the dominant element in dispersed spore assemblages. While trilete monads are generally associated with vascular plants, cryptospores lack close modern analogues (except possibly in some liverworts), making the identification of their parent plants one of evolutionary botany's significant unresolved problems.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).