IDENTIFICATION (with reason) OF Pristis sp.[Saw fish] (B.Sc. ZOOLOGY_CCF- SEMESTER5_DSCC-9)

 Identifying features are:

1. Multicellular heterotroph.
2. embryonic development, preceded by heterogametic fertilization.

            Hence, the specimen belongs to the Kingdom Animalia.

1. Presence of hollow, dorsal, tubular nerve cord.
2. Presence of notochord, at any stage of their life or throughout the life.
3.  Presence of pharyngeal gill slits & post anal tail during some stage in the ontogeny.

            Hence, the specimen belongs to the Phylum Chordata.

1. Presence of Cranium.
2. Presence of vertebral column.
3. Presence of paired lateral appendages.
4. A post anal tail usually present.

           Hence, the specimen belongs to the Sub Phylum: Vertebrata

1. Mouth is covered by functional jaws.
2. Presence of paired appendages.

       Hence, the specimen belongs to the Super Class Gnathostomata

1. Subterminal mouth is located ventrally.
2. Tail is heterocercal.
3. Presence of calcareous endoskeleton.
4. Presence of 5to7 pairs of gill-slits.

        Hence, the specimen belongs to the Class Chondrichthyes

1. The skin is covered with dermal denticles (placoid scales).
2. The pectoral fins are distinct and not fused to the head. 
3. Powerful olfactory system helps in detection of food.
4. 5 to 7 pairs of gill slits located on the sides of the head.

       Hence, the specimen belongs the Sub Class: Selachii

1. Gill slits are present on the ventral side of the body.
2. Enlarged pectoral fins.
3. Reduction in tail fin & pelvic, anal & other fins are noticeable.

       Hence, the specimen belongs to Super Order: Hypotremata

1. Fleshy body, dorsoventrally compressed.
2. Eyes are on the dorsal surface.

        Hence, the specimen belongs to Order: Rajiformes

1. Dorsoventrally flattened anterior body portion  but posterior is shark like.
2. Prolonged snout having rostral saw with a series of lateral tooth like denticles.
3. Specimen features a robust, elongated trunk with two large dorsal fins and a powerful tail, resembling the body plan of a shark rather than a typical flat ray.
4. Their rostrum is covered in thousands of tiny pores called ampullae of Lorenzini used to detect the electrical signatures of hidden prey.

     Hence, the specimen seems to be Pristis sp.

Systematic Position: (Young,1981)

Kingdom: Animalia

         Phylum: Chordata

             Sub Phylum: Vertebrata

                    Super Class: Gnathostomata

                         Class: Chondrichthyes

                               Sub Class: Selachii

                                  Super Order:Hypotremata

                                              Order: Rajiformes

                                                 Genus: Pristis