Flowers of Apocynaceae in amber from the early Eocene of India.

PREMISE: Early Eocene ambers of the Cambay lignite in Gujarat, India, are well known for their diverse insect fauna and dispersed pollen, but the included flowers have received limited attention. The fossil record of Apocynaceae is relatively poor, and the distinctive floral characters of this family have not been recognized in the fossil record before. METHODS: Remains of tiny flowers in amber were studied by micro-CT scanning, reflected light, and epifluorescence microscopy. RESULTS: Flowers of Maryendressantha succinifera gen. et. sp. n. have actinomorphic, pentamerous, tubular corollas 2.2-2.3 mm wide, and 1.7-2.1 mm deep with sinistrorse aestivation and androecia consisting of a whorl of five stamens attached by short filaments to the lower half of the corolla tube. Anthers are ovate, rounded basally and apically tapered with their connectives convergent with one another in a conical configuration. The pollen is globose, psilate, tricolporate, and very small (10-11 µm). The combined characters indicate a position within the grade known as subfamily Rauvolfioideae. CONCLUSIONS: These fossils, as the oldest remains of Rauvolfioids, complement the fossil records of Apocynoid and Asclepioid fossil seeds from other regions, demonstrating that the Apocynaceae were well established by the early Eocene, mostly consistent with prior divergence estimates for the phylogeny of this family. Potential pollinators, also preserved in the Cambay amber, include mosquitos, gnats, small moths, and stingless bees.

Study of thermoluminescence in turtle shell fossils using radiation dosimetry.

The present study describes for the first time thermoluminescence (TL) characterization of turtle shell. A fossil shell was collected from the Dongargaon area in the Chandrapur district of Maharashtra, India. TL was recorded and a comparative study of TL for the above material was performed to understand the special TL characteristics of the shell. The shell was irradiated with 60 Co γ-radiation to study its TL properties. The sample displayed two good TL peaks at 135°C and 255°C. A linear dose-response curve for the irradiated sample was produced for the dose range 0.79-28.5 kGy; this sample of turtle shell (fossil) may be useful as a high dose dosimetry phosphor in this range. This geological sample was further characterized using X-ray diffraction to confirm its phase structure and by scanning electron microscopy , Fourier transform infrared and wavelength dispersive X-ray fluorescence spectroscopy to determine morphology, vibration, and elemental composition as ppm or percentage of the sample, respectively. Kinetic parameters of the TL glow peak were calculated using three different methods.

Thermoluminescence study in fossils of dinosaur bones and eggshells.

In this study, thermoluminescence (TL) characterization of fossils of sauropod dinosaur bone, dinosaur eggshells, and associated sediments were recorded for the first time. The fossil bone was collected from the Bagwanya intertrappean sediments in the Dhar district of Madhya Pradesh, India. TL was recorded using 60 Co gamma ray exposure at different doses. Fossils of dinosaur bone, dinosaur eggshells, and associated sediments were irradiated using 60 Co gamma rays at different doses from 0.15 kGy to 19 kGy. The linear dose-response curve of the irradiated sample was obtained for a dose ranging from 0.15 kGy to 9.5 kGy. These geological samples were characterized further using X-ray diffraction for confirmation with phase, scanning electron microscopy, Fourier transform infrared spectroscopy, and wavelength dispersive-X-ray fluorescence for determination of the elemental composition in parts per million to percentage levels.