Whales, Dolphins, and Porpoises of the Western North Atlantic - LightNovelsOnl.com
You're reading novel online at LightNovelsOnl.com. Please use the follow button to get notifications about your favorite novels and its latest chapters so you can come back anytime and won't miss anything.
21. a. 8-11 teeth in each upper jaw, 8-9 in each lower jaw; body of young slate gray or brownish, adults white; short broad rostrum.
Beluga, p. 99
b. No visible teeth (or two teeth) in upper jaw of adults only; in males and sometimes females one or both of these may grow up to 9-foot (2.7 m) tusk in left-hand (sinestral) spiral; no rostrum.
Narwhal, p. 102
22. a. Head long and conical Go to 23
b. Head blunt Go to 24
23. a. 20-27 teeth in each upper and lower jaw; crowns of teeth often marked with many fine vertical wrinkles; body to about 8 feet (2.4 m).
Rough-toothed dolphin, p. 135
b. 26-35 teeth in each upper and lower jaw; teeth smooth; body to about 5.6 feet (1.7 m); distribution restricted to northern coast of South America, in the Guianas, and adjacent eastward territory of Venezuela.
Guiana dolphin, p. 132
24. a. Teeth usually at front end of lower jaw only, 2-7 pairs (rarely teeth in upper jaw); all teeth may have fallen out of the lower jaw of older specimens or may be extensively worn; forehead with median crease; dorsal fin tall and distinct to 15 inches (38.1 cm); body to 13 feet (4.0 m).
Grampus, p. 96
b. Teeth in both upper and lower jaws, 7 or more pairs, forehead with no median crease Go to 25
25. a. Flippers large and paddle-shaped, ovate, and rounded on the distal end; dorsal fin tall and erect to 6 feet (1.8 m) in males and 3 feet (0.9 m) in females; 10-12 teeth in each jaw; teeth to 1 inch (2.5 cm) in diameter.
Killer whale, p. 84
b. Flippers long and pointed Go to 26
26. a. Dorsal fin located in forward one-third of body, very broad at the base; head bulbous.
(Pilot whale) Go to 27
b. Dorsal fin located near midpoint of back; head long Go to 28
27. a. Flippers one-fifth of body length, or more.
Atlantic pilot whale, p. 91
b. Flippers one-sixth of body length, or less.
Short-finned pilot whale, p. 94
28. a. Flipper has distinctive hump on forward margin; 8-11 prominent teeth curved backwards and inwards, in each upper and lower jaw.
False killer whale, p. 88
b. Flipper lacks distinctive hump on forward margin; 10-25 teeth in each upper and lower jaw Go to 29
29. a. 8-13 teeth in each jaw.
Pygmy killer whale, p. 138
b. 20-25 teeth in each upper jaw, 21-24 teeth in each lower jaw.
Many-toothed blackfish, p. 142
30. a. Beak short, usually less than about 1 inch (2.5 cm) Go to 31
b. Beak more than 1 inch (2.5 cm) Go to 33
31. a. Flippers very short; dorsal fin small and triangular; 38-44 teeth in each jaw; body to at least 8 feet (2.4 m); distinct black stripe from beak to area of a.n.u.s; in profile beak shows very little separation from forehead.
Fraser's dolphin, p. 120
b. Flippers long relative to body length; dorsal fin tall and distinctly falcate; 22-40 teeth in each jaw; in profile, beak shows distinct separation from forehead.
(_Lagenorhynchus_ sp.) Go to 32
32. a. 22-28 teeth in each jaw; dorsal fin all black; body to about 10 feet (3.1 m).
White-beaked dolphin, p. 126
b. 30-40 teeth in each jaw (some animals have greater number in upper than in lower jaw); dorsal fin part gray, part black; body to about 9 feet (2.7 m).
Atlantic white-sided dolphin, p. 123
33. a. 20-26 teeth in the upper jaws; 18-24 in the lower jaws; body to 12 feet (3.7 m); teeth may be extensively worn.
Atlantic bottlenosed dolphin, p. 128
b. 26 or more teeth in both upper and lower jaws Go to 34
34. a. 29-36 teeth in each upper jaw; 28-36 in each lower jaw.
(Spotted dolphins) Go to 35
b. More than 40 teeth in each upper and lower jaw Go to 36
NOTE: Characters in paragraph 35 are usable only on fresh specimens.
Spotted dolphins in advanced stages of decomposition can be distinguished only with museum preparation and examination.
35. a. Bridle present (dark lines from eye to rostrum and from flippers to corner of mouth); cape on head distinct; no spinal blaze.
Bridled dolphin, p. 108
b. Bridle absent though there is a light line from the flipper to the eye; cape indistinct; spinal blaze.
Atlantic spotted dolphin, p. 104
36. a. From 46-65 small, sharply pointed teeth; body dark gray on back, tan to light gray on sides, white on belly; beak dark gray or black above, white below, and often black-tipped; body to about 7 feet (2.1 m).
Spinner dolphin, p. 110
b. From 40 to 50 teeth in each upper and lower jaw Go to 37
37. a. Body to 9 feet (2.7 m); black to dark gray on back, gray on sides, white on belly; distinctive black stripes from eye to a.n.u.s, eye to flipper, and dark dorsal coloration to side above flipper.
Striped dolphin, p. 113
b. Body to 8.5 feet (2.6 m) but usually less than 7.5 feet (2.3 m); body dark on back with light thoracic patch and crisscross or hourgla.s.s pattern on side; black stripe from middle of lower jaw to origin of flipper.
Saddleback dolphin, p. 116
[Footnote 18: Counts of ventral grooves are made between the flippers and do not include shorter grooves often found on the side of the head and on the side above the flippers.]
[Footnote 19: Blue whale has faint lateral ridges.]
[Footnote 20: By feeling between the lower jaws on the ventral surface and moving the finger forward towards the tip of the snout, one can feel the point at which the two lower jaws become united (called the symphysis). This location is an important reference point in distinguis.h.i.+ng among the species separated in paragraphs 14, 15, and 16.]
