. Early Devonian fishes from Utah : Arthrodira. Fishes, Fossil; Paleontology -- Devonian; Paleontology -- Utah. Fig. 113. Anterior medio-ventrals (AMV) and posterior medio-ventrals (PMV) of Arctolepida, all reduced to the same area. A, "Phlydaenaspis" heintzi, after Gross, 1933b (X ); B, P. acadica, after Heintz, 1933 (X ); C, Bryant- olepis sp., AMV from Bryant, 1934, PMV from PF 1551 (X ); D, Anarthraspis sp., AMV from Bryant, 1932, PMV from PF 258 (X ). s. AMV, s. AV, s. AVL, s. IL, s. PMV, s. PVL, external overlap areas for anterior medio-ventral, antero-ventral, ante
. Early Devonian fishes from Utah : Arthrodira. Fishes, Fossil; Paleontology -- Devonian; Paleontology -- Utah. Fig. 113. Anterior medio-ventrals (AMV) and posterior medio-ventrals (PMV) of Arctolepida, all reduced to the same area. A, "Phlydaenaspis" heintzi, after Gross, 1933b (X ); B, P. acadica, after Heintz, 1933 (X ); C, Bryant- olepis sp., AMV from Bryant, 1934, PMV from PF 1551 (X ); D, Anarthraspis sp., AMV from Bryant, 1932, PMV from PF 258 (X ). s. AMV, s. AV, s. AVL, s. IL, s. PMV, s. PVL, external overlap areas for anterior medio-ventral, antero-ventral, anterior ventro-lateral, intero-lateral, posterior medio-ventral, and posterior ventro-lateral. may have fused so as to have a common center of radiation at the midline anteriorly (fig. 112, I). If this is so, the median plate just behind may be the posterior medio-ventral as Heintz identified it, or the anterior medio-ventral which has been crowded posteriorly. All of these points favor the view that the antero-ventrals were present primitively in the Arctolepida and that their loss in various ways is secondary in the Phlyctaenaspinae, Williamsaspidae, and Brachythoraci. The anterior medio-ve^itral and posterior medio-ventral plates (fig. 113, AMV,PMV) lie in the midline largely between the anterior ventro- laterals; the posterior medio-ventral is also bounded posteriorly by the posterior ventro-laterals, while the anterior medio-ventral is bounded anteriorly by the intero-laterals and in the Actinolepinae by the antero-ventrals. The anterior and posterior medio-ventrals are without known exception overlapped externally by all of these paired. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Denison, Robert H. (Robert Howland), 1911-1985; Roy, Sharat Kumar, 1897-1962, joint editor Chief Curator, Dept. of Geology
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Keywords: ., bookcentury1900, bookcollectionbiodiver, booksubjectfishesfossil
