Table 2. Growth strategy groups.

Histological features used to diagnose each of the three Growth Strategy Groups are outlined here, along with group membership.

Growth Strategy Group	Diagnostic Histological Characteristics	Ischigualasto Vertebrates
GSG I—Slower and Cyclical	Dominant fibrillar organization: PFB and/or LFB Vascularity: Simple primary vascular canals with no osteonal infills and/or unidirectional primary osteons with limited anastomosis Cyclicity: Cyclical bone deposition; cycles demarcated by LAG and/or annuli Remodeling: Secondary osteons absent; remodeling only evident as IFS	Pseudochampsa
GSG II—Faster, But Cyclical	Dominant fibrillar organization: FLB, may have some regular mid-cortical regions of PFB or LFB Vascularity: Primary osteons with limited anastomosis Cyclicity: Cyclical bone deposition; cycles attenuate from deep to superficial, and are bounded by LAG and/or annuli Remodeling: Sparse secondary osteons limited to deep cortex; IFS may be present	Exaeretodon Hyperodapedon Saurosuchus
GSG III—Continually Fast	Dominant fibrillar organization: FLB Vascularity: Primary osteons abundant and interweave in complex but varying patterns Cyclicity: Bone deposition continuous until late ontogeny; late ontogeny shift to PFB/LFB, areas of avascularity, and/or EFS form. No mid- or deep-cortical growth marks Outer 1/3 of element may exhibit irregular mid-ontogeny reductions in bone appositional rate recorded by PFB/LFB, areas of reduced vascularity or avascularity, or annuli, but not by regular mid-cortical LAG Remodeling: Secondary osteons may be present, sometimes as dense Haversian bone; Mid-cortical remodeling may be present; IFS may be present.	Proterochampsa Sillosuchus Trialestes Herrerasaurus Sanjuansaurus Eodromaeus Eoraptor Chromogisaurus