IDENTIFICATION (with reason) OF Scoliodon sp. (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. Mouth is subterminal in position.
2. Multiple gill -slits are protected by individual skin flap.
3. Male bears clasper.
4. Firm & hard jaws are provided with numerous sharp teeth.

      Hence, the specimen belongs to the Sub Class Selachii

1. Gill-slits are on the lateral side of the body.
2. Pectoral fins are constricted at the base.

      Hence, the specimen belongs to the Super Order Pleurotremata

1. Two dorsal fins without spines are present.
2. Presence of a single anal fin.
3. Presence of five gill slits.

     Hence, the specimen belongs to the Order: Lamniformes

1. Body is divisible into head, thorax & abdomen.
2. Head dorsoventrally flattened but rest of the body is laterally compressed.
3. Well developed heterocercal tail is present.
4. Possess several sets of homodont teeth.
5. Spiracle is absent.

     Hence, the specimen seems to be Scoliodon sp.

Systematic Position: (Young,1981)

Kingdom: Animalia

         Phylum: Chordata

             Sub Phylum: Vertebrata

                    Super Class: Gnathostomata

                         Class: Chondrichthyes

                               Sub Class: Selachii

                                       Super Order: Pleurotremata

                                              Order: Lamniformes

                                                 Genus: Scoliodon