part of directly develops from expresses tin larva pupa developing embryonic structure somatic precursor cell trunk mesoderm derivative embryonic precursor of scutellar pulsatile organ scutellar pulsatile organ progenitor 2018-05-31T10:30:25Z Progenitor cell specified by loss of tinman expression from embryonic precursor of scutellar pulsatile organ cells. Two pairs of cells in each of the second and third thoracic segments interconnect with cytoplasmic extensions to form a ladder-like structure anterior to the heart. In late larval stages, these cells begin to divide. In the pupa, they retract into a single cluster, split and then enter the scutellum to form the scutellar pulsatile organs. fly_anatomy.ontology wing heart progenitor FBbt:00047210 scutellar pulsatile organ anlage