Whaler Sharks - seafdec.org.my

32 S h a r k s a n d R a y s o f B o r n e o
1 st dorsal-fin origin well in front of
pelvic-fin base .................................. 30
30. Precaudal pits absent (fig. 71); anterior
margin of caudal fin smooth (fig. 71)
............ Family Triakidae, Hound Sharks
fig. 70; 74
Precaudal pits present (fig. 72); anterior
margin of caudal fin usually rippled
(fig. 72) ............................................ 31
31. Spiracles present; posterior margin of
2 nd dorsal fin deeply concave; intestine
with spiral valves (fig. 73) ......................
...... Family Hemigaleidae, Weasel Sharks
a. Lower teeth near symphysis with short,
straight or weakly hooked cusps (fig. 74)
that are concealed when mouth closed;
gill slits small, less than twice eye length .. b
Lower teeth near symphysis with long,
strongly hooked cusps (fig. 75) that
prominently protrude from mouth when
closed; gill slits large, more than twice eye
length ................................................. c
b. Pelvic, dorsal and caudal fins not falcate
(fig. 76); mouth long, narrowly arched;
lower teeth near symphysis with erect
cusps and slightly arched roots; cusplets
present on lower teeth……….. Paragaleus
fig. 76; 84
Pelvic, dorsal and caudal fins strongly
falcate (fig. 77); mouth very short, broadly
arched; lower teeth near symphysis with
erect cusps and highly arched roots; no
cusplets on lower teeth ........... Hemigaleus
fig. 77; 80
c. Snout obtusely wedge-shaped in dorsoventral
view; fins not falcate, posterior
margins of pelvic and pectoral fins
straight or slightly concave (fig. 78) .......
.......................................... Chaenogaleus
fig. 78; 78
fig. 70
fig. 71 fig. 72
fig. 73
fig. 74 fig. 75
fig. 76
fig. 77
fig. 78