Table 2.

Microanatomic and histologic summary; for further discussion see text and listed figures

Specimen	Ontogenetic Age	Taxon	Microanatomy	Cortical Histology	Trabecular Histology	Figure
LACM 129639a	Mother	P. latipinnus	Spongious medulla with wide voids; remodeled endosteal boundary; Pachyostotic cortex, longitudinal vascular canals. EFS present.	Secondary osteons (Haversian); some woven bone on periphery	Large erosion rooms; secondary lamellar	6
Left femur
LACM 129639b	Fetus	P. latipinnus	Spongious medulla; clear endosteal boundary; periosteal cortex longitudinal to plexiform vascularity.	Primary woven fibered bone	Primary lamellar	7
Left scapula
UNSM 50133	Adult	D. bonneri	Spongious medulla with wide voids; remodeled endosteal boundary; pachyostotic cortex, longitudinal vascular canals. No EFS.	Secondary osteons (Haversian)	Large erosion rooms; secondary lamellar	8,11
Right humerus
UNSM 55810	Neonate	D. bonneri	Spongious medulla; clear endosteal boundary; periosteal cortex thick with longitudinal to radial vascularity; clear birth line.	Primary woven to fibrolamellar bone	Primary lamellar	9,12
Right humerus
FMNH PR 1619	Fetus	Polycotylidae	Spongious medulla; clear endosteal boundary; periosteal cortex longitudinal to radial vascularity.	Primary woven fibered bone	Calcified cartilage; primary lamellar	10,13
Right humerus