excavation

(A), silhouette of Maip macrothorax showing the preserved bones in white. (B), reconstruction of the thoracic cavity of Maip at level of D6. (C), interpretative drawing of the excavation of Maip showing the original disposition of the bones. Abbreviations: a, axis; c, coracoid; ind, indeterminate bone; g, gastralia; r, rib; v, vertebrae.

Osteohistology of UALVP 59606, metatarsal IV of Citipes elegans. Overview of histological thin section of UALVP 59606 in plane-polarized (A) and cross-polarized (B) light, showing locations of close-up images. Detail (C) of cortex showing predominantly primary fibrolamellar bone with longitudinal-reticular vascularity, endosteal layer, and cyclical growth marks (arrows), under plane-polarized light. Close-up (D) of well developed endosteal layer on the medullary cavity, showing sec- ondary excavation by simple vascular canals, under cross-polarized light. Close-up (E) of tightly packed cyclical growth marks (arrows) near the periosteal surface of the cortex, under plane-polarized light. Close-up (F) of periosteal surface of cortex, showing avascular parallel-fibered bone indicating an incipient external fundamental system (double ended arrow) with three LAGs (arrows). Abbreviations: efs, incipient external fundamental system; el, endosteal lamellae; hb, Haversian bone; pfb, parallel-fibered bone; radv, radial simple vascular canal; so, secondary osteon.