Exquisitely preserved Jurassic Perisphinctes ammonite...

Upper Jurassic Period (Oxfordian-Kimmeridgian) — This exceptional paleontological specimen presents a natural assemblage of ammonites of the genus Perisphinctes, magnificently preserved within a compact matrix. The original crystal formation of the shells has been replaced by calcite, allowing detailed fossilization of these marine cephalopods. The absence of signs of assemblage confirms the geological integrity and the in situ origin of this lot. The ammonites display the characteristic planispiral morphology, with symmetrical whorls and clear visibility of the radial ribbing. The ribbing, particularly fine and regular, bifurcates elegantly toward the periphery of the shell, a crucial distinctive feature for identifying the genus Perisphinctes. The outer surface shows coloration ranging from golden beige to light brown, with slight mineral iridescence attesting to post-mortem calcitic recrystallization. The provenance is clearly identified in the fossil beds of Sakaraha, southwestern Madagascar, a geological locality renowned for its extraordinary preservation and abundance of Upper Jurassic finds. This geological context provides valuable insights into the marine environmental conditions of about 150 million years ago, characterized by warm and life-rich waters. The aesthetics of the piece are notable, with several Perisphinctes individuals of various sizes harmoniously integrated into the matrix, creating a natural sculptural composition. The three-dimensionality and density of the specimens make this lot a focal point for any collection. It is mounted on a discreet black metal base, which facilitates display and enhances its verticality. The state of preservation is excellent, with well-preserved morphological details allowing in-depth study of the paleobiology of these organisms. No significant signs of damage or post-depositional alteration are evident that would compromise the structural or aesthetic integrity of the specimens. The matrix offers excellent contrast with the lighter tones of the fossils. From a collecting standpoint, this Perisphinctes assemblage from Sakaraha represents a specimen of considerable value. Its uniqueness as a natural unassembled formation, the specific provenance, and the preservation quality make it a desirable piece for both amateur paleontologists and experienced Jurassic fossil collectors. It stands out from single specimens for its complexity and visual impact.

估價:$201.63

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