Histochemical distribution of peroxidase in ascidians with special reference to the endostyle and the branchial sac
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Abstract This paper describes the anatomy of the larynx of an echolocating porpoise and proposes a limited role for that organ in vocalization. Gross dissection of the larynx of the bottle‐nose porpoise Tursiops truncatus reveals the features of component cartilages, muscles and joints. Arytenoid, cuneiform, and corniculate cartilages are present as an incompletely fused cartilaginous unit with each cartilage being identifiable by slight clefts of demarcation. The arytenoid cartilages are freely movable on the cricoid cartilage as a prerequisite for opening and closure of the larynx. Despite the lack of vocal folds to produce a wide range of sounds, it is proposed that the larynx of this species can produce clicks and is partially responsible for whistles.
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This study documents the presence of harbour porpoise (Phocoena phocoena, Linnaeus 1758) in the tidal Thames from strandings, dedicated surveys and opportunistic sightings. In March 2015, a visual and acoustic vessel survey for harbour porpoises was conducted; 17 sightings and 45 acoustic detections of porpoise groups were documented. A conservative acoustic encounter rate of 4.2 animals/100 km surveyed is estimated, comparable to results from acoustic surveys in other important European porpoise habitats. Presented with data from opportunistic sightings records, porpoises are reported in the tidal Thames during all months, with peak presence in spring and late summer. Results support the need for further studies in this significant habitat, and that harbour porpoises must be considered when planning future activities and developments within the estuary.
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Compared with the history of seals in the Baltic Sea, the porpoise has received much less research attention. The harbor porpoise (Phocoena phocoena) has been quite rare in the eastern Baltic in recent centuries, but according to archaeological finds, its population was quite numerous here ca. 6000–4000 years ago (ca. 4000–2000 cal. BC). This paper deals with all known archaeological assemblages of porpoise so far discovered in the eastern Baltic (Estonia, Latvia and Lithuania), discusses the hunting strategies and studies the exploitation of this small cetacean by the Neolithic hunter-gatherers. Fauna historical aspects include new archaeological data in addition to those published previously. We consider whether these new data change the temporal and spatial pattern of porpoise hunting and examine how, in addition to the expected use of porpoise meat and blubber, the porpoise’s toothed mandibles were used for patterning ceramics.
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