Plagiochasma is an extinct echinoderm genus in the family Pygaulidae.^[1]

Species includes:

• Plagiochasma cruciferum (Morton, 1830); Paleocene of Denmark, Belgium, The Netherlands, Trinidad and the United States
• Plagiochasma faringdonense (Wright, 1875); Lower Greensand, Upper Aptian, Early Cretaceous of UK
• Plagiochasma olfersii (L. Agassiz, 1836); Hauterivian, Early Cretaceous of France and Switzerland
• Plagiochasma saurai Forner i Valls, 2016; Barremian, Early Cretaceous of Spain
• Plagiochasma texanum Smith & Rader, 2009; Lower Albian, Texas, USA