(n.) A conical calcareous fossil, tapering to a point at the lower extremity, with a conical cavity at the other end, where it is ordinarily broken; but when perfect it contains a small chambered cone, called the phragmocone, prolonged, on one side, into a delicate concave blade; the thunderstone. It is the internal shell of a cephalopod related to the sepia, and belonging to an extinct family. The belemnites are found in rocks of the Jurassic and Cretaceous ages.
Example Sentences:
(1) Start your exploring at Bearreraig Bay, where, if you are lucky, you may find belemnites, ammonites and bivalves.
(2) Six Holstein cows in mid-lactation were placed on a diet naturally low in 13C (-25.0% vs Pee Dee belemnite [PDB] an international carbon isotope standard), based on alfalfa-barley, and six others were placed on a diet naturally enriched in 13C (-11.5% vs PDB), based on corn.
Mesozoic
Definition:
(a.) Belonging, or relating, to the secondary or reptilian age, or the era between the Paleozoic and Cenozoic. See Chart of Geology.
(n.) The Mesozoic age or formation.
Example Sentences:
(1) The diversity of tetrapods increased from the Devonian to the Permian, remained roughly constant during the Mesozoic, and then began to increase in the late Cretaceous, and continued to do so during the Tertiary.
(2) Major groups of modern mammals have their origins in the Mesozoic Era, yet the mammalian fossil record is generally poor for that time interval.
(3) The distribution of enamel tubules, the shapes and arrangements of prisms, and the orientation of crystals in ground sections from several therapsids and mesozoic mammals have been investigated by conventional and polarizing microscopy.
(4) Simpson's monographs of 1928 and 1929, progress in the study of Mesozoic mammals has been largely dependent on new finds.
(5) In general, the small subunit nuclear sequences appear to be best for elucidating Precambrian divergences, the large subunit nuclear sequences for Paleozoic and Mesozoic divergences, and the organellar sequences of both subunits for Cenozoic divergences.
(6) Thus, it represents a primitive lineage that was present during the diversification of turtle lineages in the mid-Mesozoic era.
(7) Of the suborders present in the Paleozoic, seven are morphologically relatively simple, slowly evolving, and continued into Mesozoic and Cenozoic times to become the ancestoral lineages from which evolved several additional post-Paleozoic suborders.
(8) That’s why the BBC series Walking with Dinosaurs put many of its computer-generated creations against the backdrop of Conguillío’s “living fossils”, which date to the mesozoic age.
(9) The preliminary implication of these observations is that the mechanism of physiological color change involving MCH and its melanophore receptors evolved near the end of the Paleozoic or during the early Mesozoic, just before or early in the evolution of neopterygian (holostean and teleostean) fishes.
(10) He has lent his name to a Mesozoic reptile, a fossilised armoured fish, a species of Ecuadorian tree, one of the world's largest-pitchered carnivorous plants, and one of only four species of long-beaked echidna.
(11) The break from constant or increasing rates during the Mesozoic to decreasing rates during the Cenozoic appears to coincide with extraordinary diversification of placental mammals at the beginning of this era.
(12) A major impetus to renewed investigation came from the discoveries of Mesozoic mammals by Walter Kühne in 1939 and during the immediate post-war years.
(13) Blanding is also home to the Blanding Dinosaur Museum , which features rotating exhibits on Utah's rich Mesozoic history, including fossilised eggs and baby dinosaurs.
(14) A model of evolutionary transformation of the dentale-tympanicum complex in mesozoic mammals in outlined on the basis of the ontogenetic findings in Monodelphis and other didelphid and dasyurid marsupials.
(15) Studies of Mesozoic mammals, begun some 150 years ago, are based on rare and fragmentary fossils, principally jaws and teeth.
(16) Paleontologic and zoogeographic data speak in favour of Mesozoic origin of ixodid ticks.