Sökning: "dorsal fin"

Hittade 4 avhandlingar innehållade orden dorsal fin.

  1. 1. Development and three-dimensional histology of vertebrate dermal fin spines

    Författare :Anna Jerve; Per Erik Ahlberg; Martin Brazeau; Tatjana Haitina; Philippe Janvier; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fin spine; paleontology; early vertebrate; histology; development; Biology with specialization in Evolutionary Organismal Biology; Biologi med inriktning mot evolutionär organismbiologi;

    Sammanfattning : Jawed vertebrates (gnathostomes) consist of two clades with living representatives, the chondricthyans (cartilaginous fish including sharks, rays, and chimaeras) and the osteichthyans (bony fish and tetrapods), and two fossil groups, the "placoderms" and "acanthodians". These extinct forms were thought to be monophyletic, but are now considered to be paraphyletic partly due to the discovery of early chondrichthyans and osteichthyans with characters that had been previously used to define them. LÄS MER

  3. 2. Neural mechanisms for the control of posture, locomotion and steering : a behavioral, electrophysiological and modeling study in lamprey

    Författare :Patriq Fagerstedt; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :reticulospinal; vestibular system; spinal cord; central pattern generator; reciprocal inhibition; fictive locomotion; fictive turning; electron microscopy; computer simulation; lamprey; dorsal fin;

    Sammanfattning : When animals move around interacting with the environment, the nervous system has to solve several tasks simultaneously in order to produce and control the movements - notably propulsion, posture, balance, and associated movements. Basic motor tasks are controlled by neuronal networks organized into central pattern generators (CPGs) and reflexes, located in the spinal cord and brainstem. LÄS MER

  4. 3. Phylogeny and species diversity of the South and Southeast Asian cyprinid genus Danio Hamilton (Teleostei, Cyprinidae)

    Författare :Fang Fang Kullander; Richard Vari; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Benfiskar; karpfiskar; fylogeni; Sydasien; Sydostasien; Systematic Zoology; zoologisk systematik och evolutionsforskning;

    Sammanfattning : Danio Hamilton, in the wide sense, consists of 66 nominal species, of which about 45 are valid. Four species, viz. D. kakhienensis, D. LÄS MER

  5. 4. Preservation of Marine Reptile Soft Parts: Reconstructing the Life and Death of Ancient Leviathans

    Författare :Randolph De La Garza; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molecular paleontology; Taphonomy; Soft-tissues; Lagerstätten; Skin; Sea Turtle; Ichthyosaur; Fur Formation; Posidonia Shale; Paleobiology; Marine Reptiles;

    Sammanfattning : Marine reptiles constitute a diverse group of secondarily aquatic tetrapods that have inhabited the world’s oceans for the greater part of the last 250 million years. While certain large-scale anatomical changes have been observed through progressive alterations of their skeletal morphology (e.g. LÄS MER