Devonian) than these other lineages 
and have retained a different body 
organization, with only three pairs of 
walking legs and five pairs of anterior 
maxillipeds. Stomatopods also possess 
a primitive neural organization, with 
three pairs of ganglia, or groups of 
nerve cells, arranged in a row above 
the mouth. In contrast, in decapods, 
isopods, and amphipods, these groups 
of neurons are condensed into a com- 
pact “brain.” In spite of the primitive 
arrangement of their ganglia, however, 
the stomatopods have strong learning 
abilities, highly active predatory hab- 
its, and a complex fighting behavior 
that is at least as sophisticated as that 
of the decapods. 
The second pair of maxillipeds in 
stomatopods is modified into a pair 
of claws. Each claw, when open, ex- 
poses a series of teeth or a toothless 
blade with a needle-sharp tip, depend- 
ing on the family to which a particular 
species belongs. In families where the 
claws bear serrated teeth, individuals 
use the appendages for snatching and 
holding soft-bodied prey such as poly- 
chaete worms and fishes. Mantis 
shrimps with snatching claws excavate 
burrows in mud or sand and attain 
larger sizes than those with bladelike 
claws. In families that have bladelike 
claws, the base of the last segment 
of the claw is swollen and heavily cal- 
cified. This type of claw is used as 
a hammer to smash hard-bodied prey 
such as snails, clams, rock oysters, 
and other crustaceans. Mantis shrimps 
with hammering, bladelike claws live 
in holes in coral or rocks and are re- 
stricted in their body size by the size 
of the available holes. These species 
are often more aggressive, more heav- 
ily armored, and more brightly colored 
than the species with snatching claws, 
which live In soft substrates. 
The predatory, or raptorial, strike 
of the bladelike claws — almost too 
quick for the eye to see — bears a 
strong resemblance to that of the ter- 
restrial praying mantis. This similarity 
is responsible for the common name 
of stomatopods, mantis shrimps. Al- 
though praying mantises and mantis 
shrimps evolved independently, on 
land and in the sea, their claw struc- 
ture, their habit of waiting concealed 
to ambush unsuspecting prey, their 
stalked, mobile eyes and visually me- 
diated behavior, and even their three 
pairs of walking legs are remarkably 
similar. Moreover, on the inside of 
each of their raptorial appendages, 
mantis shrimps, like some praying 
mantises, bear a colored spot, which 
they expose in threat displays. The 
mantis shrimps could well be consid- 
ered the marine equivalent of the ter- 
restrial praying mantises (or vice 
versa). 
Mantis shrimps are found in all 
tropical and subtropical marine wa- 
ters, but never in fresh water. Al- 
though one species is known from 
depths of more than 3,500 feet, most 
species live in shallow habitats less 
than 100 feet deep. Considered a deli- 
cacy in many cultures, the shrimps 
represent an important fishing indus- 
try in the Mediterranean, and their 
claws are prized as fishhooks in many 
areas of Oceania. Their bellicose na- 
ture, as well as their delectability, has 
earned mantis shrimps additional 
names in many languages. They are 
called “split toe” or “split thumb” 
in the West Indies, “pica” in Mexico 
and Central America, “shako” in Ja- 
pan (where they are common in fish 
markets), and “vako” in the Gilbert 
Islands. 
The mantis shrimps’ claws are used 
not only for catching food but also 
for defense, as any diver who has 
placed a finger near the entrance to 
38 
