How to Identify Scalloped Hammerhead

To identify Scalloped Hammerhead (Sphyrna lewini), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Dorsally dark bronze to olive-brown, fading to white or off-white ventrally. Fins may have dusky tips, especially in juveniles.

Scale type

placoid

Mouth position

inferior

Distinctive features

Cephalofoil (hammer-shaped head) with a distinct indentation or 'scallop' in the center of the anterior margin., Relatively small mouth compared to other large sharks., First dorsal fin is tall and falcate (sickle-shaped), originating over or slightly behind the pectoral fin axil., Second dorsal fin is relatively high with a deeply notched posterior margin., Pectoral fins are moderately long and falcate.

Dorsal fin

Two dorsal fins. The first is tall, falcate, and originates over or slightly behind the pectoral fin axil. The second is smaller but relatively high with a deeply notched posterior margin.

Tail fin

Heterocercal caudal fin; upper lobe is significantly longer than the lower lobe, with a distinct subterminal notch.

Pectoral fin

Moderately long and falcate.

Distinctive fins

The cephalofoil is the most distinctive feature, with a central indentation on its leading edge.

Identification Tips

1. 1

   Cephalofoil Shape

   Look for the distinct central indentation or 'scallop' on the leading edge of the hammer-shaped head. This is the primary distinguishing feature from other hammerhead species.

2. 2

   First Dorsal Fin Origin

   The origin of the first dorsal fin is typically over or slightly behind the pectoral fin axil. This helps differentiate it from the Great Hammerhead (Sphyrna mokarran) where the first dorsal fin originates over the pectoral fin insertion.

3. 3

   Second Dorsal Fin

   The second dorsal fin is relatively tall with a deeply notched posterior margin, which is more pronounced than in some other hammerhead species.

4. 4

   Body Coloration

   Generally bronze to olive-brown dorsally, fading to white ventrally. This coloration can be a general indicator but is not definitive on its own.

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