Growth and development of agnostids Pentagnostus proanabarensis Fedoseev, 1999

摘要: Juvenile development of the Middle Cambrian agnostid trilobite Pentagnostus proanabarensis Fedoseev, 1999 is studied. A sequence eight juvenile stages defined based on changes in morphology and measurements. Three them belong to meraspid degree 0, another three refer 1, two represent early holaspid stages. Neither frequency distribution length cephalons pygidia nor length-width scatter diagrams give clear clusters molts; number molts can be estimated through analysis posteroaxis distribution. Thus, measurements some with vestiges pleural postaxial furrows allow reconstruction segments during individual growth. At initial stage development, pygidial axis P. probably had four segments, increased up no less than six adults.