Whaler sharks


Carcharhinidae

Characteristic features:

  • Eyes with well-developed nictitating lower eyelid
  • Teeth small to large, blade like
  • Anterior teeth in upper jaw smaller than lateral teeth and not separated from them by smaller intermediate teeth on each side
  • Caudal fin strongly asymmetrical, with a rippled or undulating dorsal margin
  • Caudal-fin lower lobe well-defined
  • longitudinal keels (blue shark)
  • Precaudal pits well-developed
  • Intestinal valve of scroll type

Keys:

Key to the genera of Carcharhinidae in South-east Asia (adapted from Compagno & Niem, 1998)
    1. Upper labial furrows very long, extending forward to level of eyes (Fig. 1a); relatively large spiracles present (Fig. 2); prominent lateral keel on each side of caudal peduncle (Fig. 3); vertical dark bars on upper surfaces (can be obscure in large individuals)Galeocerdo cuvier (tiger shark)
    2. Upper labial furrows long (Fig. 1b) to rudimentary (Fig. 1c), never extending to level of eyes; spiracles usually absent; lateral keels usually absent (weak keels present in Prionace glauca); no dark vertical bars on body2
    1. Strong cusplets on most teeth in both jaws (Fig. 4); expanded nasal flaps forming a tube for the excurrent aperture (Fig. 5a)Triaenodon obesus (whitetip reef shark)
    2. Cusplets low or absent on upper teeth, usually absent on lower teeth; nasal flaps not forming a tube (Fig. 5b)3
    1. Second dorsal fin nearly as large as first dorsal fin (Fig. 6a)4
    2. Second dorsal fin much smaller than first dorsal fin (Fig. 6b)5
    1. Snout short, preoral length much less than mouth width (Fig 7a); upper and lower teeth with narrow, unserrated cusps (Fig. 8a)Negaprion acutidens (sicklefin lemon shark)
    2. Snout longer, preoral length about equal to mouth width (Fig. 7b); upper teeth with broadly triangular, serrated cusps (Fig. 8b)Lamiopsis tephrodes (Borneo broadfin shark)
    1. Head greatly depressed and trowel-shaped (Fig. 9); pectoral fins broadly triangular, length about equal to anterior margin (Fig. 10a); first dorsal-fin free rear tip about over midbases of pelvic fins (Fig. 11a); posterior margin of caudal fin only shallowly concave (Fig. 12a)Scoliodon macrorhynchos (Pacific spadenose shark)
    2. Head conical to slightly depressed; pectoral fins narrow, length less than anterior margin (Fig. 10b); first dorsal-fin free rear tip over or anterior to pelvic-fin origins (Fig. 11b); posterior margin of caudal fin deeply incised (Fig. 12b)6
    1. Second dorsal-fin origin about level with or slightly anterior to anal-fin insertion (Fig. 13a); preanal ridges very distinct and long, about as long or longer than length of anal-fin base (Fig. 14a); posterior margin of anal fin straight or shallowly concave (Fig. 15a)7
    2. Second dorsal-fin origin usually level with anal-fin origin (Fig. 13b), or in some species about level with midbase of anal fin (Fig. 13c); preanal ridges short, up to only half length of anal-fin base (Fig. 14b); posterior margin of anal fin deeply concave or deeply notched (Fig. 15b)8
    1. Posterior notches present on eyes (Fig. 16a); first dorsal-fin base 2 to 3 times in distance between pectoral and pelvic fin bases (Fig. 17a)Loxodon macrorhinus (sliteye shark)
    2. No notches on eyes (Fig. 16b); first dorsal-fin base usually less than 2 times in distance between pectoral and pelvic fin bases (Fig. 17b) (up to 2 times in adult R. acutus) Rhizoprionodon
    1. A weak lateral keel present on each side of caudal peduncle (Fig. 18); first dorsal-fin base much closer to pelvic- than to pectoral-fin bases (Fig. 19a); papillose gill rakers present on gill arches (Fig. 20a); upper surfaces brilliant dark bluePrionace glauca (blue shark)
    2. No lateral keels on caudal peduncle; first dorsal-fin base midway between pectoral- and pelvic-fin bases (Fig 19b); no papillose gill rakers on gill arches ; upper surfaces greyish, brownish to greyish black9
    1. Precaudal pits longitudinal and relatively shallow (Fig. 21a); second dorsal fin 1/2 height of first dorsal fin (Fig. 22a)Glyphis gangeticus (Ganges shark)
    2. Precaudal pits transverse, deep and crescentic (Fig. 21b); second dorsal fin 2/5 or less height of first dorsal fin (Fig. 22b) Carcharhinus (requiem sharks)
Key to the species of Rhizoprionodon in South-east Asia (adapted from Compagno & Niem, 1998)
    1. furrows long and prominent, 1.4–2.0% of TL (Fig. 1a); teeth numerous, usually 25 upper rows and 24 lower rowsRhizoprionodon acutus (milk shark)
    2. Upper labial furrows short and inconspicuous, less than 1% of TL (rarely up to 1.3% TL), uppers usually shorter than lowers (Fig. 1b); teeth less numerous, 23–25 upper rows and 21–24 lower rows2
    1. 7–16 enlarged hyomandibular pores just behind mouth corners in total from both sides of head (Fig. 2a); precaudal vertebrae 84–91Rhizoprionodon oligolinx (grey sharpnose shark)
    2. 15–22 enlarged hyomandibular pores just behind mouth corners in total from both sides of head (Fig. 2b); precaudal vertebrae 73–80Rhizoprionodon taylori (Australian sharpnose shark)
Key to the species of Carcharhinus in South-east Asia (adapted from Compagno & Niem, 1998)
    1. First dorsal and pectoral fins very broad distally with broadly rounded tips, only tapering slightly toward their tips (Fig. 1a); most fin tips mottled white in adults (juveniles with black-tipped fins and a black dorsal saddle on caudal peduncle)Carcharhinus longimanus (oceanic whitetip)
    2. First dorsal and pectoral fins tapering towards pointed or narrowly rounded tips (Fig. 1b); fin not mottled white in adults, often black-tipped but never with a black saddle on caudal peduncle2
    1. First dorsal, pectoral, pelvic, and caudal fins with extremely conspicuous white tips and posterior edgesCarcharhinus albimarginatus (silvertip shark)
    2. Fins not conspicuously tipped and edged with white (although some C. amblyrhynchos have a white-tipped first dorsal fin)3
    1. Second dorsal fin with a conspicuous black tip but all other fins plain4
    2. Second dorsal fin plain, white or black-tipped but never the only fin with markings5
    1. First dorsal fin falcate (Fig. 2a); snout not flattened, rounded in dorsal view; precaudal vertebral centra 153–160Carcharhinus sealei (blackspot shark)
    2. First dorsal fin triangular, not falcate (except in some juveniles) (Fig. 2b); snout slightly flattened, somewhat pointed in dorsal view; precaudal vertebral centra 113–129Carcharhinus dussumieri (whitecheek shark)
    1. Caudal fin prominently black-edged along entire posterior margin (Fig. 3); first dorsal fin plain or white-tipped, never black-tippedCarcharhinus amblyrhynchos (grey reef shark)
    2. Caudal fin either plain or narrowly black-edged, but if black-edged first dorsal fin also prominently black-tipped6
    1. A distinct dermal ridge present between dorsal fins (interdorsal ridge) (Fig. 4)7
    2. No interdorsal ridge11
    1. Second dorsal fin, pectoral fin, and ventral caudal-fin lobe strikingly black-tippedCarcharhinus sorrah (spot-tail shark)
    2. Fins plain or dusky-tipped but not strongly black-tipped8
    1. First dorsal-fin origin well behind free rear tips of pectoral fins (Fig. 5a); inner margin of second dorsal fin very long, usually over twice (but rarely down to 1.6) times fin height (Fig. 6a); very coarse serrations or small cusplets on base of upper anterolateral teeth (Fig. 7a)Carcharhinus falciformis (silky shark)
    2. First dorsal-fin origin over or anterior to free rear tips of pectoral fins (Fig. 5b); inner margin of second dorsal fin shorter and generally less than twice fin height (but up to 2.1 times fin height in Carcharhinus obscurus) (Fig. 6b); serrations on feet of upper anterolateral teeth small and not very coarse (Fig. 7b)9
    1. First dorsal-fin origin opposite or somewhat in front of free rear tips of pectoral fin but closer to them than pectoral-fin insertions (Fig. 8a)Carcharhinus obscurus (dusky shark)
    2. First dorsal-fin origin in front or over pectoral-fin insertions or at least closer to insertions than to free rear tips of pectoral fins (Fig. 8b)10
    1. First dorsal fin very high (except in newborn individuals), its height about 1/2 of predorsal length (Fig. 9a); distance from nostrils to mouth more than 2.4 times in mouth width (Fig. 10a); upper anterolateral teeth moderately high, usually in 14 rowsCarcharhinus plumbeus (sandbar shark)
    2. First dorsal fin lower, its height much less than 1/2 of predorsal length (Fig. 9b); distance from nostrils to mouth less than 2.4 times in mouth width (Fig. 10b); upper anterolateral teeth very high, usually in 15 rowsCarcharhinus altimus (bignose shark)
    1. Entire posterior margin of caudal fin with a narrow but obvious black edge (Fig. 11); pectoral, second dorsal, and caudal fins with obvious black tips; first dorsal fin with a broad black blotch at its apex, highlighted below with white (Fig. 12)Carcharhinus melanopterus (blacktip reef shark)
    2. Posterior margin of caudal fin not black or only partly dusky or blackish; fins black-tipped or not; first dorsal fin, if black-tipped, not broadly black-tipped12
    1. Snout very short and broadly rounded (Fig. 13a); upper anterolateral teeth with very broad, triangular cusps and straight to concave distal margins; lower anterolateral teeth with strongly arched roots (Fig. 14a)13
    2. Snout longer and parabolic or wedge-shaped to pointed (Fig. 13b); upper anterolateral teeth with narrow cusps and strongly notched distal margins; lower anterolateral teeth with nearly straight roots (Fig. 14b)14
    1. First dorsal-fin height more than 3.1 times second dorsal-fin height (Fig. 15a); angle of notch in anal-fin posterior margin more acute, usually less than a right angle (Fig. 16a); usually 11 lower anteroposterior teeth, with extremely broad cusps (Fig. 17a); precaudal centra 89–95Carcharhinus amboinensis (pigeye shark)
    2. First dorsal-fin height less than 3.1 times the second dorsal-fin height (Fig. 15b); angle of notch in anal-fin posterior margin more obtuse, usually a right angle or more (Fig. 16b); usually 12 lower anteroposterior teeth, with moderately broad cusps (Fig. 17b); precaudal centra 101–123Carcharhinus leucas (bull shark)
    1. Second dorsal-fin origin well behind anal-fin origin, about level with its midbase (Fig. 18a)15
    2. Second dorsal-fin origin about level with anal-fin origin (Fig. 18b)16
    1. Rostrum expanded as a hypercalcified, hardened mass, easily detected by pinching or cutting into the snout; upper anterolateral teeth with large mesial and distal cusplets and no serrations (Fig. 19a); no enlarged pores alongside mouth corners (Fig. 20b)Carcharhinus macloti (hardnose shark)
    2. Rostrum not hypercalcified; upper anterolateral teeth with distal cusplets and serrations (Fig. 19b); hyomandibular pores conspicuously enlarged alongside mouth corners (Fig. 20b)Carcharhinus borneensis (Borneo shark)
    1. First dorsal fin relatively low, its height more than 2.2 times in the interdorsal space (Fig. 21a); first dorsal-fin origin over or just behind rear tips of pectoral fins (Fig 22a); upper labial furrows noticeably elongated and prominent (Fig. 23a); usually at least 16 rows of upper anteroposterior teethCarcharhinus brevipinna (spinner shark)
    2. First dorsal fin higher, its height 2.2 times or less in interdorsal space (Fig. 21b); first dorsal-fin origin over or just behind insertions of pectoral fins (Fig. 22b); upper labial furrows shorter and less noticeable (Fig. 23b); usually 15 or less rows of upper anteroposterior teeth17
    1. Snout rather short and wedge-shaped, internarial space 1.0–1.2 times in preoral snout (Fig. 24a); second dorsal height 1.0–1.2 times in inner margin length (Fig. 25a)Carcharhinus amblyrhynchoides (graceful shark)
    2. Snout relatively long and pointed, internarial space 1.3–1.7 times in preoral snout (Fig. 24b); second dorsal height 1.1–1.6 times in inner margin length (Fig. 25b)18
    1. Pelvic fins with distinct black tips on ventral surface (Fig. 26a); precaudal centra 88–109 Carcharhinus limbatus (blacktip shark)
    2. Pelvic fins plain or with dusky tips on ventral surface (if black-tipped, less than 1% of fin area black) (Fig. 26b); precaudal centra 82–91Carcharhinus tilstoni (Australian blacktip shark)

Similar families:

Lamnidae
mackerel sharks
Lamnidae line
Lamnidae differ in having no nictitating lower eyelids (vs. well-developed nictitating lower eyelids); caudal fin lunate and near symmetrical, upper and lower lobes of similar length (vs. strongly asymmetrical caudal fin with the upper lobe longer than the lower); a caudal peduncle strongly depressed dorsoventrally and expanded laterally (vs. caudal peduncle not greatly flattened dorsoventrally); longitudinal keels prominent, extending well out from peduncle (vs. weak (prionace glauca) or none) and intestinal valve ring type (vs. scroll type).

Species:

Carcharhinus limbatus
Common blacktip shark
Carcharhinus longimanus
Oceanic whitetip shark
Carcharhinus macloti
Hardnose shark
Carcharhinus melanopterus
Blacktip reef shark
Carcharhinus sealei
Blackspot shark
Carcharhinus sorrah
Spot-tail shark
Carcharhinus tilstoni
Australian blacktip shark
Carcharhinus tjutjot
Indonesian whaler shark
Glyphis gangeticus
Ganges shark
Lamiopsis tephrodes
Borneo broadfin shark
Loxodon macrorhinus
Sliteye shark
Prionace glauca
Blue shark
Rhizoprionodon oligolinx
Grey sharpnose shark
Rhizoprionodon taylori
Australian sharpnose shark
Scoliodon macrorhynchos
Pacific spadenose shark
Triaenodon obesus
Whitetip reef shark

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