Abstract
Fresh functional-morphological observations and theoretical considerations warrant a re-analysis of the traditional assumptions that the head skeleton of sharks consists of the chondrocranium and visceral arches and that the pectoral fin girdle is part of the appendicular skeleton. The scapulocoracoid cartilage of the Spiny Dogfish (Squalus acanthias) plays at least three major roles: (1) As a mechanical separator between the lateral undulations of the trunk and the vertical movements of the visceral arches; (2) as a structural basis for the anchoring of the pectoral fins: and (3) as the place of origin of the cucullaris and hypobranchial muscles which not only open the jaws and expand the branchial basket, but at the same time also affect the contractions of the heart and the timing of blood flow through the gills. Hence, the scapulocoracoid cartilage is an integral part of the head. It most likely evolved in connection with the evolution of the jaw apparatus and not simply as a part of the appendicular skeleton. Furthermore, the head is a mechanically coherent system, in which the central alimentary, circulatory, respiratory and nervous systems of the organism converge. These central feeding, respiratory and circulatory functions are not simply choreographed by the central nervous system, but are concatenated by the mechanical construction of the head itself. Such a conceptualization of the selachian head raises fresh questions concerning the constraints and potentialities of the evolutionary transformations of the various components of the head and pectoral appendages during the transition from aquatic pisciform to terrestrial tetrapod vertebrates.
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References
Butler, P. J. (1999): Respiratory system. — In:Hamlett, W. C. [ed]: Sharks, skates, and rays: The biology of elasmobranch fishes. — pp. 174–197, Baltimore (Johns Hopkins University Press).
Clack, J. A. (1989): Discovery of the earliest-known tetrapod stapes [see comments]. — Nature,342 (6248): 425–427.
Clack, J. A. (1994):Acanthostega gunnari, a tetrapod from Greenland; the snout, palate and ventral parts of the braincase, with a discussion of their significance. — Meddelelser om Grønland, Geoscience,31: 3–34.
Clack, J. A. (1998): A new early Carboniferous tetrapod with a mélange of crown-group characters. — Nature,394 (2): 66–69.
Clack, J. A. &Coates, M. I. (1995):Acanthostega gunnari, a primitive, aquatic tetrapod? — Bull. Mus. natl. Hist. nat. Paris, 4e sér.,17: 359–372.
Coates, M. I. (1994). The origin of the vertebrate limbs. — Development1994 Supplement: 169–198.
Coates, M. I. &Clack, J. A. (1990): Polydactyly in the earliest known tetrapod. — Nature,347: 66–69.
Compagno, L. J. V. (1999): Endoskeleton. — In:Hamlett, W. C. [ed]: Sharks, skates, and rays: The biology of elasmobranch fishes. — pp. 69–92, Baltimore (Johns Hopkins University Press).
Diogo, R., Oliveira, C. &Chardon, M. (2001): On the osteology and myology of catfish pectoral girdle, with a reflection on catfish (Teleostei: Siluriformes) plesiomorphies. — Journal of Morphology,249: 100–125.
Duncker, H.-R. (2001): The emergence of macroscopic complexity. — Zoology,103: 240–259.
Ferry, L. A. &Lauder, G. V. (1996). Heterocercal tail function in leopard sharks: A three-dimensional kinematic analysis of two models. — Journal of Experimental Biology,199: 2253–2268.
Graham, J. B., Dewar, H., Lai, N.C., Korsmeyer, K. E., Fields, P. A., Knower, T., Shadwick, R. E., Shabetai, R. &Brill, R. W. (1994): Swimming physiology of pelagic fishes. — In:Maddock, L.,Bone, Q. &Rayner, J.M.V. [eds]: Mechanics and physiology of animal swimming. — pp. 63–74, London (Cambridge University Press).
Hamlett, W.C. 1999. Sharks, skates, and rays: The biology of elasmobranch fishes. — Baltimore (Johns Hopkins University Press).
Herkner, B. (1999): Über die evolutionäre Entstehung des tetrapoden Lokomotionsapparates der Landwirbeltiere. — Ein konstruktionsmorphologisches Transformationsmodell auf evolutionstheoretischer Grundlage. — Carolinea-Beiheft,13: 353.
Homberger, D. G. (1988): Models and tests in morphology: The significance of description and integration. American Zoologist,28 (1): 217–229.
Homberger, D. G. &Walker, W. F. (in press): Vertebrate Dissection. — Balmount, California (Brooks/Cole).
Hughes, G. M. (1972): The relationship between cardiac and respiratory rhythms in the dogfishScyliorhinus canicula. — Journal of Experimental Biology,57: 415–434.
Hughes, G. M. &Ballintijn, C. M. (1965): The muscular basis of the respiratory pumps in the dogfish (Scyliorhinus canicula). — Journal of Experimental Biology,43: 363–383.
Jarvik, E. (1965): On the origin of girdles and paired fins. — Israel Journal of Zoology,14: 141–172.
Jeffery, J. E. (2001): Pectoral fins of rhizodontids and the evolution of pectoral appendages in the tetrapod stem-group. — Biological Journal of the Linnean Society,74: 217–236.
Kardong, K. V. (1998): — Vertebrates: Comparative Anatomy, Function, Evolution. — Boston (McGraw-Hill).
Kimmmel, C.B., Miller, C.T. &Keynes, R.J. (2001): Neural crest patterning and the evolution of the jaw. — Journal of Anatomy,199: 105–119.
Lai, N. C., Graham, J. B., Bhargava, V. &Shabetai, R. (1996): Mechanisms of venous return and ventricular filling in elasmobranch fish. — American Journal of Physiology,270 (Heart and Circulation Physiology,39): H1766–1771.
Lebedev, O. A. (1984): The first find of a Devonian tetrapod vertebrate in USSR. — Dok. Akad. Nauk. SSSR,278: 1470–1473.
Lebedev, O. A. &Clack, J. A. (1993): Upper Devonian tetrapods from Andreyevka, Tula Region, Russia. — Palaeontology,36 (Part 3): 721–734.
Liem, K. F. &Summers, A. P. (1999): Muscular system: Gross anatomy and functional morphology of muscles. — In:Hamlett, W. C. [ed]: Sharks, skates, and rays: The biology of elasmobranch fishes. — pp. 93–114, Baltimore (Johns Hopkins University Press).
Liem, K.F., Bemis, W.E., Walker, W.F., &Grande, L. (2001): Functional anatomy of the vertebrates: An evolutionary perspective. — Fort Worth (Harcourt College Publishers).
Luther, A. (1909): Untersuchungen ueber die vom N. trigeminus innervierte Muskulatur der Selachier (Haie und Rochen). — Acta Societatis Scientiarum Fennicae,36: 1–145.
Mabee, P. M. (2000): Developmental data and phylogenetic systematics: Evolution of the vertebrate limb. — American Zoologist,40: 789–800.
Marinelli, W. &Strenger, A. (1959): Superklasse: Gnathostomata. (Kiefermäuler). Klasse: Chondrichthyes. (Knorpelfische). — In:Marinelli, W. &Strenger, A. [eds]: Vergleichende Anatomie und Morphologie der Wirbeltiere. III. Lieferung. — pp. 173–308, Wien (Verlag Franz Deuticke).
Marion, E. (1905): Mandibular and pharyngeal muscles ofAcanthias andRaia. — American Naturalist,39: 891–924.
Motta, P. J. &Wilga, C. D. (2001): Advances in the study of feeding behaviors, mechanisms, and mechanics of sharks. — Environmental Biology of fishes,60: 131–156.
Peters, D. S. (1993): Konstruktionszwänge bei der Skelettentwicklung am Beispiel der Tetrapoden-Gliedmaßen. — Praxis der Naturwissenschaften,42 (8): 38–43.
Romeis, B. (1989): Mikroskopische Technik. — 17. Auflage, München, Wien, Baltimore (Urban & Schwarzenberg).
Romer, A. S. (1966): Vergleichende Anatomie der Wirbeltiere. — Hamburg, Berlin (Parey).
Satchell, G. H. (1960): The reflex coordination of the heart beat with respiration in the dogfish. — Journal of Experimental Biology,37: 719–731.
Satchell, G. H. (1999): Circulatory system: Distinctive attributes of the circulation of elasmobranch fish. — In:Hamlett, W. C. [ed]: Sharks, skates, and rays: The biology of elasmobranch fishes. — pp. 218–237, Baltimore (Johns Hopkins University Press).
Shubin, N. H. &Alberch, P. (1986): A morphogenetic approach to the origin and basic organization of the tetrapod limb. — Evolutionary Biology,20: 319–387.
Starck, D. (1979): — Vergleichende Anatomie der Wirbeltiere. Band 2: Das Skelettsystem. — Berlin, Heidelberg, New York, Tokyo (Springer).
Taylor, E. W. (1985): Control and co-ordination of gill ventilation and perfusion. Symposia of the Society for Experimental Biology,39: 123–161.
Van den Assem, J. (1952): The relation between the muscles and skull structure in the Regio branchialis inSqualus acanthias L. I and II. Proceedings of the Koninklijke Nederlandse Academie van Wetenschappen, Series C,55 (5):656–664; 665–674.
Walker, W. F. &Homberger, D. G. (1992): Vertebrate Dissection. — Philadelphia (Saunders College Publishing).
Wilga, C. D. &Lauder, G. V. (2000): Three-dimensional kinematics and wake structure of the pectoral fins during locomotion in leopard sharksTriakis semifasciata. — Journal of Experimental Biology,203: 2261–2278.
Wilga, C. D. &Lauder, G. V. (2001): Functional morphology of the pectoral fins in Bamboo Sharks,Chiloscyllium plagiosum: Benthic vs. pelagic station-holding. — Journal of Morphology,248: 1–15.
Wilga, C. D. &Motta, P. J. (1998): Conservation and variation in the feeding mechanism of the spiny dogfishSqualus acanthias. — Journal of Experimental Biology,201 (9): 1345–1358.
Wilga, C. D., Wainwright, P. C. &Motta, P. J. (2001): Evolution of jaw depression mechanics in aquatic vertebrates: insights from Chondrichthyes. — Biological Journal of the Linnean Society,71: 165–185.
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Gudo, M., Homberger, D.G. The functional morphology of the pectoral fin girdle of the Spiny Dogfish (Squalus acanthias): Implications for the evolutionary history of the pectoral girdle of vertebrates. Senckenbergiana lethaea 82, 241–252 (2002). https://doi.org/10.1007/BF03043787
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DOI: https://doi.org/10.1007/BF03043787