A skeletal muscle fiber found at the fetal and neonatal stages. In mammalian fetuses and neonates, skeletal muscle expresses myosin heavy chain-neonatal (MyHC-neo, encoded by the MYH8 gene). This expression disappears shortly after birth and is replaced by expression of adult heavy chain myosins. [ http://www.ncbi.nlm.nih.gov/pubmed/7196501 http://www.ncbi.nlm.nih.gov/pubmed/26180627 http://orcid.org/0000-0003-2034-601X ]