Stenopus hispidus        

Identification Resources

1) Identification to the Family level

S. hispidus is quite different from the infraorder Caridea which most of the shrimps belong to. They are classified in their own separate infraorder, the Stenopodidea, which include coral shrimps and Venus shrimps. Within this evolutionary branch, coral shrimps are the most familiar members of the group. It is thought to be because they are often photographed and described as characteristic animal of the sub-tropical and tropical reef.

Stenopodideans are different from carideans in having the pleura of the first abdominal overlapping the second instead of the second overlapping the first and also the third.
The third pereopod is chelate and bigger than the second, which is distinct from carideans where the second pereopod is in most cases the largest and is not chelate.
A modified pleopod 1 called the petasma in males is absent. Also, males gills are trichobranchiate, with thousands of thin filaments.
Females pleopods are used to carry eggs as for cardideans.

A key diagnosis can be created for Identification of the memer of this family.
- Peropods 1, 2 and 3 chelate.
- Third pereopod usually much longer than the others,without exopods.
- Abdominl somites with pleura not expanded, they overlap in sequence posteriorly.
- Pleopods in both sex are uniramous
- Male without petasma
- Female carry eggs attached to pleopods.
- Trichobranchiated gills, central axis with irregular rows of simple filaments.

Key to families of Stenopodiae:
- The telson end in two strong spines
- The body is compressed
- Uropodal endopod has two longitudinal ridges.


2) Identification to the species level

There is still a few differences that allow to further classified stenopodidens. Tomomi et al, 2009, have elaborated a key based on morphological traits that allow species classification of the stenopus family members.

1. - Antennal scale with rows of spines on dorsal surface..............................................................4
    - Antennal scale without or with only a few spines on dorsal surface........................................2

2. - First pereopod carpus armed with row of well spaced dorsal smal spines...............................3
    - First pereopod carpus unarmed.......................................................S. earlei (Indo-West Pacific)

3. - Sixth pleonal somite with spines irregularly arranged.......................S. goyi (Indo-West Pacific)
    - Sixth pleonal somite with spines irregularly arranged with oblique rows...................................
      ......................................................................... S. scutellatus (Western Atlantic, Gulf of Mexico)

4. - Fourth pleonal somite with small spines arranged in transverse rows.....................................5
    - Fourth pleonal somite with irregularly arranged small spines...................................................6

5. - Third pleonal somite with narrow shield-shaped bare area posterodorsally; telson with 1
       lateral spine; antennal scale serrated along entire lateral margin............................................
       ...................................................... S. spinosus (Mediterranean, Amphi-Atlantc, Gulf of Mexico)
     - Third pleonal somite without bare area posterodorsally; telson without lateral spines;
       antennal scale with subdistal lateral margin unarmed except for terminal tooth......................
       ............................................................................................. S. pyrsonotus (Indo-West Pacific)

6. - Fourth and fifth pereopod carpi and propodi not subdivided....................................................7
    - Fourth and fifth pereopod carpi and propodi subdivided..........................................................8

 7. - Rostrum unarmed with 8 ventral teeth; telson with 3 or 4 lateral spines..................................
      ......................................................................................... S. chrysexanthus (Indo-West Pacific)
    - Rostrum unarmed on ventral margin; telson with 1 lateral spine...............................................
      ............................................................................................. S. zanzibaricus (Indo-West Pacific)

8. - Fourth pleonal somite without mesial bare area; 4^th and 5^th Pereopods densely covered with    
      dorsomesial spines on carpi, meri and Ischia............................................................................9 
     - Fourth pleonal somite with a large cross-like bare area mesially; 4^th and 5^thPereopods 
       without or only with a few dorsomesial spines on carpi, meri and Ischia...............................10

 9. - Exopod of third maxilliped without lateral spines; carpi of 4^th and 5^th pereopods armed with 2-6      
      movable distoventral spines........................................................S. devaneyi (Indo-West Pacific)
    - Exopod of third maxilliped with lateral spines; carpi of 4^th and 5^th pereopods without movable           
      distoventral spines........S. tenuirostris (Indo-West Pacific)