XI.—<i>An Account of the Great Finner Whale</i> (Balænoptera Sibbaldii) <i>stranded at Longniddry</i> Part I. The Soft Parts.

Turner, Wm.

doi:10.1017/s0080456800026454

Cited by 19 publications

(15 citation statements)

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“…We have substituted a toothed whale, Tursiops truncatus, as this is the species for which placentation is best known (Wislocki and Enders,'41). The sparse data available for Balaenoptera (Turner, 1870) and on early development in Megaptera (Stump et al,'60) Douady et al (2002b) relied mainly on sequences from Elephas. Information is much more thorough on placentation in Loxodonta, and includes ultrastructural studies (Allen et al, 2003;Wooding et al, 2005).…”

Section: Methodsmentioning

confidence: 99%

Evolutionary transformations of fetal membrane characters in Eutheria with special reference to Afrotheria

2005

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Analysis of molecular data sets has provided new insights into higher-level relationships of living Eutheria, including the recognition of Afrotheria as a novel taxon. This offers an opportunity to take a fresh look at the evolution of organ systems, including some that are little used in traditional systematics. In the present study, we attempted a reconstruction of the evolution of characters associated with placentation, the fetal membranes and the female reproductive tract. The evolutionary history of 21 characters has been traced, based on a current hypothesis of eutherian relationships, by applying the computer program MacClade. Accordingly, the analysis provides a first comprehensive interpretation of the stem species pattern of Eutheria. Of particular note, this pattern includes an endotheliochorial chorioallantoic placenta. The reconstructed pattern of Eutheria does not change in the basal nodes of the group. Thus, no character transformations occur on the stem lineages of Laurasiatheria or Euarchontoglires, and even Afrotheria has mostly plesiomorphic character conditions. However, two character transformations occur on the common stem lineage of Afrotheria and its sister taxon Xenarthra, i.e., amniogenesis by cavitation instead of folding and the precocial state of the newborn. In addition, we recognized one character transformation on the stem lineage of Afrotheria, i.e., the occurrence of a four-lobed allantoic sac. Thus, contrary to previous assertions, it is possible to identify morphological characters that could be synapomorphic for this novel taxon.

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Section: Methodsmentioning

confidence: 99%

Evolutionary transformations of fetal membrane characters in Eutheria with special reference to Afrotheria

2005

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“…Turner [2] showed that they have epitheliochorial placentation. For the baleen whales (suborder Mysticeti) our knowledge has advanced little further [3], since available specimens often have been in too poor condition for histology [4].…”

Section: Introductionmentioning

confidence: 99%

Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis

Silva

Carter

Ambrósio

et al. 2007

Reprod Biol Endocrinol

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A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allantochorion. The interhemal membrane of the placenta was of the epitheliochorial type. Two different types of trophoblastic epithelium were seen. Most was of the simple columnar type and indented by fetal capillaries. However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries. The endometrium was well vascularised and richly supplied with actively secreting glands. These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

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“…As mysticetes do not possess such structures, sound production is thought to occur solely in their larynx (Purves and Pilleri, 1983). Although vocal folds (vocal cords, true vocal cords, or true cords) are the prime generator of initial laryngeal sounds in terrestrial mammals, it is currently widely accepted that mysticetes lack them (Carte and MacAlister, 1867;Turner, 1870;Dubois, 1886;Hosokawa, 1950;Purves and Pilleri, 1983;Quayle, 1991;Paterson et al, 1993;Haldiman and Tarpley, 1993). Thus, other regions of the larynx have been suggested as possible sound sources (Beauregard and Boulart, 1882;Benham, 1901;Hosokawa, 1950;Sukhovskaya and Yablokov, 1979;Henry et al, 1983;Reeb and Best, 1999).…”

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confidence: 99%

Discovery of a low frequency sound source in Mysticeti (baleen whales): Anatomical establishment of a vocal fold homolog

Reidenberg

Laitman

2007

The Anatomical Record

105

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The mechanism of mysticete (baleen whale) vocalization has remained a mystery. Vocal folds (true vocal ''cords''), the structures responsible for sound production in terrestrial mammals, were thought to be absent in whales. This study tests the hypothesis that the mysticete larynx possesses structures homologous to vocal folds and that they are capable of sound generation. Laryngeal anatomy was examined in 37 specimens representing 6 mysticete species. Results indicate the presence of a U-shaped fold (U-fold) in the lumen of the larynx. The U-fold is supported by arytenoid cartilages, controlled by skeletal muscles innervated by the recurrent laryngeal nerve, is adjacent to a diverticulum (laryngeal sac) covered with mucosa innervated by the superior laryngeal nerve, and contains a ligament-conditions that also define the vocal folds of terrestrial mammals and, therefore, supports homology. Unlike the vocal folds of terrestrial mammals, which are perpendicular to airflow, the mysticete U-fold is oriented parallel to airflow. U-fold adduction/abduction and elevation/depression may control airflow, and vibration of its edges may generate sounds. The walls of the laryngeal sac can expand and contract, may serve as a resonant space, and may also propagate vibrations generated by movements of the supporting arytenoid cartilages. The extensive musculature surrounding the laryngeal sac may enable rapid and forceful expulsion of air from the lumen of the sac into other respiratory spaces, or maintain a constant sac volume despite the effects of ambient pressure (e.g., changes during diving or ascent). The size and complexity of the mysticete larynx indicates an organ with multiple functions, including protection during breathing/swallowing, regulation of airflow and pressures in the respiratory spaces, and sound generation. The presence of a vocal fold homolog offers a new insight into both the mechanism of sound generation by mysticetes and the divergent evolution of odontocete and mysticete cetaceans. Anat Rec, 290:745-759, 2007. 2007 Wiley-Liss, Inc.

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XI.—An Account of the Great Finner Whale (Balænoptera Sibbaldii) stranded at Longniddry Part I. The Soft Parts.

Cited by 19 publications

References 0 publications

Evolutionary transformations of fetal membrane characters in Eutheria with special reference to Afrotheria

Evolutionary transformations of fetal membrane characters in Eutheria with special reference to Afrotheria

Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis

Discovery of a low frequency sound source in Mysticeti (baleen whales): Anatomical establishment of a vocal fold homolog

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