Phocoena phocoena, the harbour porpoise
- is a stocky, rotund animal with a broad-based, low, triangular dorsal fin and small, oval pectoral flippers.
- has a short-beaked head with a dark line that runs from the back of the mouth to the leading edge of the dorsal fin.
- has a comparatively thick layer of blubber which varies in thickness over the body. Blubber thickness can also be affected by nutritional status.
- are very dark grey to black on their back, becoming speckled/intermediate on their sides and white on their underside.
- has straight mouth-line slopes upwards towards the eye (Jefferson et al, 2008).
- tail flukes are defined by a deep median notch, have concave trailing edges and rounded tips (Watson, 1981).
- has 19-28 teeth in each tooth row (Jefferson et al, 2008). Each tooth has a cylindrical ‘neck’, flattened into a spatulate form at the tip.
- tongue has finger-like extensions around its edge known as marginal lingual papillae. These are age-related structures helping to seal the mouth during suckling and then aiding the eating of solid food whilst excluding seawater following weaning (Natural History Museum, 2002).
Four subspecies are recognized (IUCN, 2009):
- Phocoena. p. phocoena in the North Atlantic
- Phocoena. p. vomerina, in the eastern North Pacific
- Phocoena. p. relicta in the Black Sea (Reeves and Notarbartolo di Sciara 2006)
- An un-named subspecies in the western North Pacific (Rice, 1998)