Ultrastructure du parenchyme sécréteur de la glande postanale du cælacanthe, &lt;i&gt;Latimeria chalumnae&lt;/i&gt; Smith

Lemire, M; Lagios, Michael D.

doi:10.1159/000145050

Cited by 13 publications

(3 citation statements)

References 17 publications

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“…11A). Sarcopterygian monophyly has been disputed by some (e.g., Lemire and Lagios, 1979;Ldvtrup, 1977;Wiley, 1979;Lagios, 1979;Jarvik, 1980; see below for dicussion). Characters supporting sarcopterygian monophyly are given by Lauder (1979), Forey (1980), Rosen et.…”

Section: Sarcopterygiimentioning

confidence: 99%

Heads and Tails: A Chordate Phylogeny

1986

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A cladistic analysis of chordates is presented, based on some 320 nested characters. All the principal higher taxa are defined by synapomorphies, including extinct acanthodians and placoderms. The data base draws broadly from adult anatomy (including osteological data for Recent and fossil taxa), embryology, physiology, and biochemistry. A conventional sequence of chordate higher taxa is generated (hemichordates, urochordates, cephalochordates, craniates). Among the craniates, cyclostomes are considered paraphyletic. Gnathostomes are monophyletic, but two fossil "agnathan" groups (galeaspids, osteostracans) are regarded as stem gnathostomes. Chondrichthyans and osteichthyans are monophyletic. New arguments for osteichthyan affinity of acanthodians are presented. The phylogenetic position of placoderms is still problematic, but they can no longer be perceived as stem chondrichthyans or even as "elasmobranchiomorphs." Recent dipnoans and tetrapods are sister groups, but new paleontological discoveries refute many of their supposed osteological synapomorphies, thereby reopening the possibility of a closer relationship between tetrapods and osteolepiform rhipidistians. CLADISTICS[VOL. 2 204 CLADISTICS[VOL. 2 of motor nerves in the ventral "roots" of cephalochordates (Flood, 1966) are probably primitive conditions. Contrary to Jefferies (1979), I do not think muscle innervation patterns in tunicates, echinoderms, and cephalochordates offer any clear indication of their interrelationships, and it may be that motor nerve end plates arose independently in adult thaliacean tunicates and in craniates, whereas the remaining similarities between tunicates and craniates are most parsimoniously regarded as primitive.The supposed presence of chitin in the cephalochordate branchial endoskeleton suggested to Ldvtrup (1977:94) that chordates are not monophyletic. R&r (1982) presented convincing evidence that although the branchial skeleton of Amphioxus is not collagenous, neither is it chitinous; instead the branchial rods probably consist of acid mucopolysaccharides and proteins. Ldvtrup's (1977) hypothesis of chordate non-monophyly is not substantially helped whether cephalochordate branchial bars consist of chitin or mucopolysaccharides; their structure in the first case could be primitive; in the second case it is most economically regarded as a synapomorphy of cephalochordates. Other possible cephalochordate synapomorphies include the tentacular oral languets, ciliated wheel organ, and Hatschek's nephridium. Hatscheck's pit may be the homolog of the craniate pituitary (Goodrich, 1917;De Beer, 1925, 1926, but nothing is known of cephalochordate endocrine function (Barrington, 1968).Although accepting cephalochordates as the sister group of craniates, Janvier (1981: 122) stated that they "show hardly any precise and surely homologous synapomorphy . . . sufficient to reject comparisons between the Chordata and other groups."However, cephalochordates and craniates are united by the following characters that have not been identi...

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Section: Sarcopterygiimentioning

confidence: 99%

Heads and Tails: A Chordate Phylogeny

1986

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“…There are two schools of thought as regards the taxonomic affinities of the coelacanth. Lovtrup (1977)) Lagios (1979)) Lemire & Lagios (1979) and some others ally L. chalumnae with the Chondrichthyes, whereas Compagno (1979), Forey (1980, Lund & Lund (1985), Maisey (1986), Robineau (1986)) Smith & Heemstra (1986)) Schultze (1986)) Trueb & Cloutier (1989) and others regard the coelacanth as a primitive sarcopterygian member of the Osteichthyes (truly fleshy-finned sarcopterygians, Radinsky 1987). The features that L. chaZumnae shares with the cartilaginous fishes include: a rectal gland, a certain type of pituitary gland, similar means of osmoregulation by retaining urea and trimethylamine oxide in the blood and secretions of the rectal gland, very large eggs, fatty livers, and similarities in the structure of the eye, pancreas and spinal chord.…”

Section: Phylogenetic Relationshipsmentioning

confidence: 99%

A fiftieth anniversary reflection on the living coelacanth, Latimeria chalumnae: some new interpretations of its natural history and conservation status

Balon

Bruton²,

Fricke

1988

Environ Biol Fish

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SynopsisIt all started about 400 million years ago, when representatives of a group of fish-like fleshy-finned creatures appeared in the fossil record (or was it through a childhood dream shared by all of us that we would one day study the coelacanth?). Many of the coelacanth's characters placed them close to the ancestry of terrestrial vertebrates. About 70 million years ago they disappeared from the fossil record. The discovery in 1938 of the first living coelacanth, in 1952 of the second and until now over 200 specimens parallels in excitement an encounter with a live dinosaur on a weekend walk, and in significance even more than that. For this year's 50th anniversary of the famous discovery of the first living coelacanth, we retraced the routes and visited the main actors of this zoological drama. New insights into coelacanth natural history were facilitated by novel interpretation of earlier data and our expeditions to the Comoro Islands, retracing the route of the second specimen, measuring unrecorded specimens, interviewing fishermen and describing their fishing crafts, and taking part in recent events on land and water near the only known habitat of the living coelacanth. Entry into this habitat and observations from the research submersible GE0 opened up a new era in coelacanth research. Past studies of preserved specimens, which were caught as an incidental bycatch, were supplemented for the first time by studies of free-living coelacanths in their natural habitat. The first film footage taken from the submersible revealed the entirely unfishlike movements of this creature. Its mode of locomotion is a combination of flying and gliding, interspersed with head stands and belly-up drifts which appear to defy gravity. The narrow range of habitat in which the coelacanth has been encountered has led us to realize how vulnerable this ancient relict is. The members of our expeditions therefore cooperated in establishing an international organisation to coordinate efforts to conserve the coelacanth.

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“…Ses elements essentiels sont des acino-tubuli de type sereux, densement serr6s les uns contre les autres, tres variables de forme et de diametre interieur. Lemire (1977), dans une etude ultrastructurale de la avec le haut niveau de l'ATPase (Na-K) trouv6 par Griffith & Burdick (1976) dans des homogenats de glande postanale. Ainsi cette glande de Latimeria s'apparenterait a la glande rectale digitiforme des selaciens, a laquelle on a reconnu un role principal de regulation osmotique interne par excretion de solutions salines.…”

Section: Travauxunclassified

Évocation des travaux français sur Latimeria notamment depuis 1972

1980

Proc. R. Soc. Lond. B.

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French research on Latimeria published before 1972 is first briefly recalled. After the Anglo-Franco-American Expedition of 1972, the material obtained enabled us to focus attention on the histology of the kidney and ureter and on ultrastructural aspects of the postanal gland. Ovarian eggs of unusual volume have been collected, measured and weighed. Kinematic analysis of the intracranial articulation was carried out in 1973 on a frozen coelacanth that reached Paris. Studies in 1974 of a 41 cm specimen, the smallest known at that time and estimated to be 3½ years old, showed that the brain still filled the cranial cavity: thus, it is later that allometric growth of the cranial cavity relegates the brain to the posterior part of the skull. In the same specimen, radiographed after injection with colloidal barium oxide, we were able to specify the likely role of the contractile organs fused to the branchial arteries: they may serve to regulate arterial pressure in the head during sudden movements of the jaws, and thus of the anterior cranium, as prey is captured. Lastly, the structural characteristics of the teeth, scale denticles, and spines on the lepidotrichia have been revealed, as also has the lamellar structure of the scales, in which there is a crossed orientation of the fibres in the different layers. Brève évocation des travaux français effectués sur Latimeria avant 1972. Après l’expédition anglo-franco-américaine de 1972 le matériel obtenu a permis une mise au point de l'histologie du rein, de l’uretère et des aspects ultra-structuraux de la glande postanale. Des ovules nus d’un volume inusité, ont été recueillis, mesurés et pesés. Une analyse des mouvements de l’articulation intracrânienne a été réalisée en 1973 sur un coelacanthe arrivé congelé à Paris. En 1974, un spécimen de 41 cm, le plus petit à cette époque, a fait voir qu’à ce stade, dont l’âge a été évalué à trois ans et demi, l’encéphale emplissait encore la cavité crânienne; c’est done plus tard que la cavité crânienne subit une croissance allo-métrique reléguant le cerveau dans l’arrière crâne. Par ce même spécimen, soumis à la cinéradiographie avec injection à la baryte colloïdale, le rôle vraisemblable des organes contractiles greffés sur les artères branchiales a pu être précisé: ils doivent servir à une régulation de la pression artérielle céphalique lors des mouvements brusques des mâchoires, et par conséquent de l’avant-crâne, dans la capture des proies. Enfin l’identité structurale des dents, des denticules des écailles et des épines superficielles des lépidotriches a été mise en évidence, ainsi que la structure lamellaire des écailles avec une orientation régulièrement décalée des fibres de ses différentes couches.

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Ultrastructure du parenchyme sécréteur de la glande postanale du cælacanthe, <i>Latimeria chalumnae</i> Smith

Cited by 13 publications

References 17 publications

Heads and Tails: A Chordate Phylogeny

Heads and Tails: A Chordate Phylogeny

A fiftieth anniversary reflection on the living coelacanth, Latimeria chalumnae: some new interpretations of its natural history and conservation status

Évocation des travaux français sur Latimeria notamment depuis 1972

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