The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. It is called the Age of Reptiles and the Age of Conifers; the Mesozoic is one of three geologic eras of the Phanerozoic Eon, preceded by the Paleozoic and succeeded by the Cenozoic. The era is subdivided into three major periods: the Triassic and Cretaceous, which are further subdivided into a number of epochs and stages; the era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs. The Mesozoic was a time of significant tectonic and evolutionary activity; the era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between cooling periods. Overall, the Earth was hotter than it is today.
Dinosaurs first appeared in the Mid-Triassic, became the dominant terrestrial vertebrates in the Late Triassic or Early Jurassic, occupying this position for about 150 or 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic; the first mammals appeared during the Mesozoic, but would remain small—less than 15 kg —until the Cenozoic. The flowering plants arose in the Triassic or Jurassic and came to prominence in the late Cretaceous when they replaced the conifers and other gymnosperms as the dominant trees; the phrase "Age of Reptiles" was introduced by the 19th century paleontologist Gideon Mantell who viewed it as dominated by diapsids such as Iguanodon, Megalosaurus and Pterodactylus. Mesozoic means "middle life", deriving from the Greek prefix meso-/μεσο- for "between" and zōon/ζῷον meaning "animal" or "living being"; the name "Mesozoic" was proposed in 1840 by the British geologist John Phillips. Following the Paleozoic, the Mesozoic extended 186 million years, from 251.902 to 66 million years ago when the Cenozoic Era began.
This time frame is separated into three geologic periods. From oldest to youngest: Triassic Jurassic Cretaceous The lower boundary of the Mesozoic is set by the Permian–Triassic extinction event, during which 90% to 96% of marine species and 70% of terrestrial vertebrates became extinct, it is known as the "Great Dying" because it is considered the largest mass extinction in the Earth's history. The upper boundary of the Mesozoic is set at the Cretaceous–Paleogene extinction event, which may have been caused by an asteroid impactor that created Chicxulub Crater on the Yucatán Peninsula. Towards the Late Cretaceous, large volcanic eruptions are believed to have contributed to the Cretaceous–Paleogene extinction event. 50% of all genera became extinct, including all of the non-avian dinosaurs. The Triassic ranges from 252 million to 201 million years ago, preceding the Jurassic Period; the period is bracketed between the Permian–Triassic extinction event and the Triassic–Jurassic extinction event, two of the "big five", it is divided into three major epochs: Early and Late Triassic.
The Early Triassic, about 252 to 247 million years ago, was dominated by deserts in the interior of the Pangaea supercontinent. The Earth had just witnessed a massive die-off in which 95% of all life became extinct, the most common vertebrate life on land were lystrosaurus and euparkeria along with many other creatures that managed to survive the Permian extinction. Temnospondyls would be the dominant predator for much of the Triassic; the Middle Triassic, from 247 to 237 million years ago, featured the beginnings of the breakup of Pangaea and the opening of the Tethys Sea. Ecosystems had recovered from the Permian extinction. Algae, sponge and crustaceans all had recovered, new aquatic reptiles evolved, such as ichthyosaurs and nothosaurs. On land, pine forests flourished, as did groups of insects like mosquitoes and fruit flies. Reptiles began to get bigger and bigger, the first crocodilians and dinosaurs evolved, which sparked competition with the large amphibians that had ruled the freshwater world mammal-like reptiles on land.
Following the bloom of the Middle Triassic, the Late Triassic, from 237 to 201 million years ago, featured frequent heat spells and moderate precipitation. The recent warming led to a boom of dinosaurian evolution on land as those one began to separate from each other, as well as first pterosaurs. During the Late Triassic, some advanced cynodonts gave rise to the first Mammaliaformes. All this climatic change, resulted in a large die-out known as the Triassic-Jurassic extinction event, in which many archosaurs, most synapsids, all large amphibians became extinct, as well as 34% of marine life, in the Earth's fourth mass extinction event; the cause is debatable. The Jurassic ranges from 200 million years to 145 million years ago and features three major epochs: The Early Jurassic, the Middle Jurassic, the L
Suchosaurus is a spinosaurid theropod dinosaur from Cretaceous England believed to be a genus of crocodile. The type material consists of teeth. Two species, S. cultridens and S. girardi have been named. About 1820, Gideon Mantell acquired teeth discovered near Cuckfield in the Wadhurst Clay of East Sussex, part of a lot with the present inventory number BMNH R36536. In 1822, he reported these, as belonging to crocodiles. In 1824, the teeth were mentioned and illustrated by Georges Cuvier, representing the first illustration of a spinosaurid fossil. In 1827 Mantell described additional teeth, pointing out the similarities to the crocodylian Teleosaurus and Gavialis. One of these teeth is the present specimen BMNH R4415, others are part of BMNH R36536. In 1841, Richard Owen named, based on BMNH R36536 as a syntype series, a subgenus Crocodylus with as type species Crocodylus cultridens; the subgeneric name was derived from Greek σοῦχος, the name of the Egyptian crocodile god Sobek. This reflected the presumed taxonomic affinities.
The specific name is derived from Latin culter, "dagger", dens, "tooth", in reference to the elongated form of the teeth. In 1842, Owen again mentioned the taxon as a subgenus, subsequently he and other workers would use it as a full genus Suchosaurus. In 1842 and 1878 Owen referred some vertebrae to Suchosaurus, but these belong to Ornithischia instead. In 1884, Owen indicated a tooth as "Suchosaurus leavidens" in a caption, this is seen as a lapsus calami because this species is not further mentioned. In 1897, Henri-Émile Sauvage named a second species: Suchosaurus girardi, based on two jaw fragments and a tooth, found in Portugal by Paul Choffat; the specific name honours French geologist Albert Girard. The tooth was considered lost but was rediscovered and in 2013 reported as specimen MNHN/UL. I. F2.176.1, part of remains recovered after a fire in 1978. During the nineteenth and most of the twentieth century, Suchosaurus was considered to have been some obscure crocodilian belonging to the Pholidosauridae.
Single comparable teeth discovered in England were referred to the genus. However, when publishing a redescription of Baryonyx in 1998, Angela Milner realised that the teeth of that spinosaurid dinosaur were similar to those of Suchosaurus. In 2003, she suggested both genera represented the same animal. An identity would imply the name. However, the Suchosaurus teeth are indistinguishable from those of Cristatusaurus and Suchomimus, making it an indeterminate baryonychine. In 2007 Eric Buffetaut considered the teeth of S. girardi similar to those of Baryonyx except for the stronger development of the crown ribs, suggesting that the remains belonged to the same genus. Buffetaut agreed with Milner that the teeth of S. cultridens were identical to those of B. walkeri, but with a ribbier surface. The former taxon might be a senior synonym of the latter, depending on whether the differences were within a taxon or between different ones. According to Buffetaut, since the holotype specimen of S. cultridens is one worn tooth and that of B. walkeri is a skeleton it would be more practical to retain the newer name.
In 2011 Portuguese palaeontologist Octávio Mateus and colleagues agreed that Suchosaurus was related to Baryonyx, but considered both species in the former genus nomina dubia since their holotype specimens were not considered diagnostic and could not be equated with other taxa. First post of a long discussion of Suchosaurus as a dinosaur and its implications, in the Dinosaur Mailing List Archives
Bryozoa are a phylum of aquatic invertebrate animals. About 0.5 millimetres long, they are filter feeders that sieve food particles out of the water using a retractable lophophore, a "crown" of tentacles lined with cilia. Most marine species live in tropical waters, but a few occur in oceanic trenches, others are found in polar waters. One class lives only in a variety of freshwater environments, a few members of a marine class prefer brackish water. Over 4,000 living species are known. One genus is solitary and the rest are colonial; the phylum was called "Polyzoa", but this term was superseded by "Bryozoa" in 1831. Another group of animals discovered subsequently, whose filtering mechanism looked similar, was included in "Bryozoa" until 1869, when the two groups were noted to be different internally; the more discovered group was given the name Entoprocta, while the original "Bryozoa" were called "Ectoprocta". However, "Bryozoa" has remained the more used term for the latter group. Individuals in bryozoan colonies are called zooids, since they are not independent animals.
All colonies contain autozooids, which are responsible for excretion. Colonies of some classes have various types of non-feeding specialist zooids, some of which are hatcheries for fertilized eggs, some classes have special zooids for defense of the colony; the class Cheilostomata have the largest number of species because they have the widest range of specialist zooids. A few species can creep slowly by using spiny defensive zooids as legs. Autozooids supply nutrients to non-feeding zooids by channels. All zooids, including those of the solitary species, consist of a cystid that provides the body wall and produces the exoskeleton and a polypide that contains the internal organs and the lophophore or other specialist extensions. Zooids have no special excretory organs, the polypides of autozooids are scrapped when the polypides become overloaded by waste products. In autozooids the gut is U-shaped, with the mouth inside the "crown" of tentacles and the anus outside it. Colonies take a variety of forms, including fans and sheets.
The Cheilostomata produce mineralized exoskeletons and form single-layered sheets which encrust over surfaces. Zooids of all the freshwater species are simultaneous hermaphrodites. Although those of many marine species function first as males and as females, their colonies always contain a combination of zooids that are in their male and female stages. All species emit sperm into the water; some release ova into the water, while others capture sperm via their tentacles to fertilize their ova internally. In some species the larvae have large yolks, go to feed, settle on a surface. Others feed for a few days before settling. After settling, all larvae undergo a radical metamorphosis that destroys and rebuilds all the internal tissues. Freshwater species produce statoblasts that lie dormant until conditions are favorable, which enables a colony's lineage to survive if severe conditions kill the mother colony. Predators of marine bryozoans include nudibranchs, sea urchins, crustaceans and starfish.
Freshwater bryozoans are preyed on by snails and fish. In Thailand, many populations of one freshwater species have been wiped out by an introduced species of snail. A fast-growing invasive bryozoan off the northeast and northwest coasts of the US has reduced kelp forests so much that it has affected local fish and invertebrate populations. Bryozoans have spread diseases to fish fishermen. Chemicals extracted from a marine bryozoan species have been investigated for treatment of cancer and Alzheimer's disease, but analyses have not been encouraging. Mineralized skeletons of bryozoans first appear in rocks from the Early Ordovician period, making it the last major phylum to appear in the fossil record; this has led researchers to suspect that bryozoans arose earlier but were unmineralized, may have differed from fossilized and modern forms. Early fossils are of erect forms, but encrusting forms became dominant, it is uncertain. Bryozoans' evolutionary relationships to other phyla are unclear because scientists' view of the family tree of animals is influenced by better-known phyla.
Both morphological and molecular phylogeny analyses disagree over bryozoans' relationships with entoprocts, about whether bryozoans should be grouped with brachiopods and phoronids in Lophophorata, whether bryozoans should be considered protostomes or deuterostomes. Bryozoans and brachiopods strain food out of the water by means of a lophophore, a "crown" of hollow tentacles. Bryozoans form colonies consisting of clones called zooids that are about 0.5 millimetres long. Phoronids resemble bryozoan zooids but are 2 to 20 centimetres long and, although they grow in clumps, do not form colonies consisting of clones. Brachiopods thought to be related to bryozoans and phoronids, are distinguished by having shells rather like those of bivalves. All three of these phyla have a coelom, an internal cavity lined by mesothelium; some encrusting bryozoan colonies with mineralized exoskeletons look like small corals. However, bryozoan colonies are founded by an ancestrula, round rather than shaped like a normal zooid of that species.
On the other hand, the founding
Philippe Thomas was a French veterinarian and amateur geologist who discovered large deposits of phosphates in Tunisia. Despite the huge economic importance of his discovery, he received little recognition during his life. Monuments to Thomas in Tunisia were destroyed. Philippe Thomas was born in Duerne, Rhône, on 4 May 1843, he attended the École nationale vétérinaire d'Alfort, where he was a brilliant student, the Cavalry School. He was named an Army Veterinarian in 1865, he was assigned to Algeria, but returned to France at the start of the Franco-Prussian War and fought in various engagements. He returned to Algeria after the war and took part in suppression of the revolt in the Kabylie in 1871. In his spare time he studied geology and other scientific disciplines. Thomas became a qualified geologist. Thomas classified the succession of Eocene rocks in Algeria from the Mediterranean coast to the Sahara, a succession that he would again find in southern Tunisia. In 1873 in the M'Fatah massif of Algeria Thomas was the first to discover the existence of phosphated nodules from the lower Eocene.
In 1875 he studied the fluvio-lacustrine terrains of the Upper Tertiary and Quaternary, published a series of notes on palaeontology and palaeoethnology. The first, on "Buhalus Antiqus" appeared in the Bulletin of the Climatological Society of Algiers. In the same bulletin he reported the discovery of a prehistoric workshop in Hassi-El-M'Kadden, near Ouargla. In 1876 the Société des Sciences physiques, naturelles et climatologiques d'Alger recognized his work between 1868 and 1875 in geology and palaeontology by awarding him a silver medal; this was soon followed by his admission to the Société géologique de France. Between 1880 and 1884 Thomas published several papers on his Algerian research, with the mining engineer Jules Tissot investigated the Eocene formations in the Constantine region, where Tissot suspected the presence of calcium pyrophosphate. Thomas was the first to discover phosphates in the province of Algeria. In 1882 Jules Ferry, Minister of Public Instruction, decided to create a mission to explore the Regency of Tunisia.
The expedition was headed by the botanist Ernest Cosson, who had undertaken eight study trips in Algeria between 1852 and 1880. It included other naturalists; the botanists undertook their work in 1883 and 1884. In 1884 a geological section under Georges Rolland was added to the Tunisian Scientific Exploration Mission. Rolland was assisted by Philippe Thomas from 1885 and by Georges Le Mesle in 1887. Thomas was 42, he was assigned to the expedition at the recommendation of the paleontologist Jean Albert Gaudry, because Jules Ferry knew his ability and perfect knowledge of the Arabic language. Rolland covered the centre of the country, while Thomas worked further south and Le Mesle worked in the north, apart from an expedition to the extreme south; the team gave good descriptions of the Jurassic of the Zaghouan region and the Eocene of the Maktar and Kairouan regions. In 1885–86 Thomas explored the southern area of Tunisia between the meridian of Kairouan and the Saharan chotts, covering a vast area.
He explored the western area, which his colleagues had neglected the Chaîne du Thaljah or Chaîne du Tseldja mountains that stretch westward from Gafsa into Algeria. He identified the geology of the Gafsa chain with that of the M'fatah massif in Algeria and on 18 April 1885 found phosphates at Jebel Tselja, he found a brown or greenish gray limestone that on average contains 60% tricalcium phosphate near Métlaoui, where the Cretaceous limestone axis of the mountains joins the Eocene foundations. Thomas crossed the Chaîne du Tseldja through the dramatic gorges of the Oued and found identical phosphate deposits on the southern slope of the range extending for at least 80 kilometres. Thomas sent rock samples to the École des Mines de Paris for analysis, on receiving the results on 18 October 1885 informed Dr. Cosson, head of the mission; the discovery had great agricultural importance. With Cosson's authorization he informed the French Academy of Sciences on 7 December 1885, he completed his observations in the 1886 exploration campaign in southern and central Tunisia up to Kalaat es Senam.
Thomas sent a second note to the Academy of Sciences in 1887, a third in 1888 in which he described his 1878 observations and the Algerian deposits. He did not have the time or resources to travel the Dyr of Tébessa to confirm the presence of the phosphates that he expected to be found there, but the deposit was found as predicted, was the first to be exploited. Philippe Thomas published the palaeontology results of the Scientific Exploration Mission in six instalments plus an atlas, giving the work of Victor-Auguste Gauthier, Arnould Locard, Auguste Péron and Henri Émile Sauvage. Thomas was promoted to First Class Veterinarian in 1895; when he retired he was made an officer of the Legion of Honour. In 1898 a member of the Institute of Carthage revived interest in his work; when the Sfax–Gafsa railway was inaugurated in 1899 Thomas was made a member of the Tunisian Order of Glory. In 1900 he was award a small pension of 6,000 francs, he was awarded a Gold Medal by the Geographic Society of France in 1904.
Thomas continued to send regular notes on his findings until 1909. In 1902 the Ministry of Education proposed that Georges Rolland should write up the results of the Scientific Mission, but he refused for health reasons; the task was given to Thomas, now in retirement. He wrote the Essai d'une description géologique de la Tunisie wi
The Plesiosauridae are a monophyletic group of plesiosaurs. A family Plesiosauridae was first named by John Edward Gray in 1825
Étienne Alexandre Arnould Locard known as Arnould Locard, was a French naturalist and geologist. His name can be abbreviated/spelled as Arnoul for example Crosse. Born in Lyon, he was the son of engineer Eugene Locard, he was a student at École Centrale Paris. He is considered one of the more prolific malacologists of the so-called "new school" with Jules René Bourguignat as his master. Locard is credited with describing hundreds of zoological species, in particular freshwater mussels and gastropods from the genus Helix. During his career he did little collecting of specimens himself, preferring to work in an institution/museum environment. In 1895, he revised the conchological collection of Jacques Philippe Raymond Draparnaud. Among his many publications are articles on the geology of the Lyon region, treatises on fossil and living mollusks, he was the author of detailed biographies of naturalists, such as Martial Étienne Mulsant and Gaspard Michaud, wrote an article on Lyonnaise malacologists, titled Malacologistes lyonnais.
In 1877 he published Malacologie Lyonnaise. In 1893 Philippe Thomas published the palaeontology results of the Tunisian Scientific Exploration Mission in six instalments plus an atlas, giving the work of Victor-Auguste Gauthier, Arnould Locard, Auguste Péron and Henri Émile Sauvage. Locard was a member of the Académie des sciences, belles-lettres et arts de Lyon, the Société française de malacologie, the Société géologique de France and the Société linnéenne de Lyon 1881–1904, president- 1882), he was a founding member of the Association lyonnaise des amis des sciences naturelles. 1881-1890. Contributions à la Faune malacologique française. Ann. Soc. linn. Lyon et Ann. Soc. Hist. nat. Agric. Arts utiles Lyon. regroupant 15 mémoires. 1884-1887. Matériaux pour servir à l'histoire de la Malacologie française. Bull. Soc. mal. Fr. Paris. Regroupant 7 mémoires. 1884. Histoire des Mollusques dans l'Antiquite. 1888-1898. Notices conchyliologiques. L'Echange, Revue linnéenne, Lyon. rassemblant 50 mémoires. Taxa described by Arnould Locard include: 1882 Cernuella aginnica Helicella bolenensis Chilostoma crombezi Spiralix rayi Urticicola isaricus 1886 Alvania simulans Locard, 1886 Mitrella lanceolata Nassarius ovoideus Odostomia megerlei Setia amabilis 1889 Mytilaster marioni 1891 Haedropleura forbesi Locard, 1891 Pleurotomella reconditum Raphitoma servaini 1892 Bela decussata Bela oceanica Bela zonata Cerithiopsis scalaris Emarginula tenera Locard, 1892 Ondina crystallina Locard, 1892 Peringiella elegans Pollia scabra Locard, 1892 Retusa candidula 1893 Dreissena anatolica Locard, 1893 Dreissena gallandi Locard, 1893 Dreissena siouffi Locard, 18931894 Oxychilus colliourensis 1896 Calliostoma cleopatra Kryptos koehleri Mesalia flammifera 1897 Abyssochrysos eburneus Amauropsis brassiculina Bathybela nudator Bathybela tenelluna Bulla mabillei Locard, 1897 Cadulus artatus Locard, 1897 Cadulus monterosatoi Locard, 1897 Clathurella salarium P. Fischer in Locard, 1897 Coralliophila monterosatoi Cylichnium africanum Drilliola Locard, 1897 Eulimella nana Locard, 1897 Euthriostoma saharicum Favartia bojadorensis Fissidentalium semivestitum Fusinus sectus Gadila senegalensis Gadila strangulata Gibberula abyssicola Locard, 1897 Granulina minusculina Gregorioiscala pachya Gymnobela abyssorum Hexaplex saharicus Inopinodon azoricus Latiromitra Locard, 1897 Latirus rugosissimus Marginella marocana Locard, 1897 Mitrella nitidulina Modulus turbinoides Oenopota graphica Oliva flammulata dolicha Locard, 1897 Pagodula cossmanni Pedicularia decurvata Locard, 1897 Periapta polygyrella Relichna simplex Ringicula pirulina Locard, 1897 Spirotropis monterosatoi Stylopsis marioni Locard, 1897 Timbellus leucas Turbonilla atlantica Turbonilla pauperata Locard, 1897 Volvarina cernita 1898 Bathysciadium costulatum Calliostoma milneedwardsi Calliostoma obesulum Capulus simplex Locard, 1898 Cardiomya striolata Cetoconcha transversa Cuspidaria semirostrata Locard, 1898 Emarginula elata Locard, 1898 Emarginula intervecta Locard, 1898 Gibbula corallioides Locard, 1898 Halicardia carinifera Hyalopecten parvulinus Megaxinus appendiculatus Nuculana vestita Panacca africana Policordia densicostata Rhinoclama nitens Solariella cingulima Solariella effossima Locard, 1898 Solariella mogadorensis Solariella rudecta Talochlamys abscondita Turcicula miranda Vertambitus triangularis Verticordia triangularis Locard, 18981899 P