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You are here : Home Key characters of different genera and species
| Last Updated:: 31/03/2016

Key characters of different genera and species

 

Cartilaginous Fishes (Chondrichthyes)
 
1. Order          : Orectolobiformes
Family                        :  Stegostomatidae
 
Stegostoma fasciatum (Hermen, 1783)
 
            Common name: Tiger shark
            Vernacular name : Pulisura
 

 

  1. Nostrils close to front of snout, with short barbells and nasoral grooves connecting them with the mouth but with out circumnasial grooves.
  2.  Caudal fin nearly or quite half of total length with the lower lobe hardly developed.
  3. A strong colour pattern changing with growth. 

 

 

Colour: A strongly marked colour pattern, changing with growth. Shading into the whitish ventral surface.

 

(S. fasciatum - Adult)

 
(S. fasciatum - Young)
 
 
 
 
2. Order          :Carchariniformes
Family                        : Carcharhinidae
 
Carcharhinus limbatus (Valenciennes, in Muller and Henle, 1839)
 
            Common name : Black tip shark
            Vernacular name : Vellaisura
 
  1. Second dorsal fin less than half the height of first dorsal fin
  2. First dorsal fin with appointed or very narrowly rounded apex , its origin above or slightly posterior to insertion of pectoral fins.
  3. No dermal ridge between dorsal fins. 
 

 

Colour: Back dark grey, ash blue or dusky bronze. Belly white or yellowish. Tips of pelvic fins with a persistent black spot.

 

Carcharhinus limbatus

Scoliodon laticaudus (Muller and Henle, 1838)

Common name: Milk shark
Vernacular name: Paalsura

1. Head and snout broader and more flattened, body stouter.
2. First dorsal fin moderately large, its origin well behind pectoral free rear tips, its base closer to pelvic than to pectoral fin bases, and its free rear tip over or behind middle of pelvic fin base.
3. Caudal fin not deeply notched on its posteroventral margin.

 

 

Colour: Bronze grey above, white below, fins sometimes darken than body, no conspicuous markings

 

 

Scoliodon laticaudus

 

Family : Sphyraenidae

Sphyrna zygaena (Linnaeus, 1758)

Common name : Hammer head shark
Vernacular name : Suthiyalsura

1. Median indentation absent from anterior margin of head.
2. Anal fin base about as large as that of second dorsal fin.
3. A free rear tip ending well anterior to upper caudal fin origin and a nearly straight to shallow concave posterior margin.

 

 

Colour: The colour of the fish grey to grayish brown above shading to white below. Its pectoral fins tipped with grey or black ventrally.

Sphyrna zygaena


3. Order : Rajiformes
    Family : Pristidae

Pristis microdon (Latham, 1794)

Common name: Sawfish
Vernacular name : Rambasura

1. Rostral teeth narrow, not greatly depressed and spike- like in deep narrow sockets on the rostrum and 17to 22 pairs of rostral teeth
2. Caudal fin without a subterminal notch, with a short ventral lobe or more.

 

Colour: Uniform olive – green above, dirty cream below.

 

Pristis microdon

 

 

Family : Rhinobatidae

Rhina ancylostoma (Bloch & Schneider, 1801)

Common name : Guiter fish
Vernacular name : Kallu uluvai

1. Snout broad, rounded. First dorsal fin triangular, its origin anterior to base of pelvic fins. Second dorsal fin similar in shape but slightly smaller.
2. Eyes slightly smaller and entirely separated from spiracles.

Colour: Dark brown on dorsal region and milky white on ventral side.

 

Rhynchobatus djeddensis (Forsskal, 1775)

Common name : Giant Guiter fish
Vernacular name : Padangan

1. Snout long and pointed
2. Eyes larger than and immediately anterior to spiracles
3. Posterior margin of spiracles with two cutaneus folds.
4. First dorsal fin triangular, above base of pelvic fins.

  

Colour: The fish is dark olive-green to dark brown above with numerous scattered white spots. These spots may not be evident in living specimens encountered under water.
 

Rhynchobatus djeddensis

Family : Dasyatidae

Dasyatis uarnak (Gmelin, 1789)

Common name : Sting ray
Vernacular name : Mullu thirukkai

1. Mouth long, undulated, with a transverse series of four fleshy papillae on floor of mouth, outer two smaller than two inner ones.
2. Tail 2.6 to 3.0 time longer than disc.
3. Serrated spines, which number 1 to 3 and which originate about 1.3 times interspiracular distance posterior to hind angle of disc.

 

Colour: Dorsal surface dark brown in middle and light brown at sides, covered with yellow spots. Ventral surface whitish. About 67 brown bands along tail alternating with white.

Dasyatis uarnak

Family : Myliobatidae

Aetomylaeus nichofi (Bloch & Schneider, 1801)

Common name : Striped Eagle ray
Vernacular name : Kurivi thirukkai

1. Disc about twice as wide as long. Sub rostral fin (snout) unilobed.
2. Eye- diameter 3.5 times in snout length.
3. Single dorsal fin at base of tail, its origin opposite ends of pelvic fin base, no caudal spine.

Colour: The colour of the barbells eagle ray is dark brown dorsally with 3-5 greyish – blue bands on its disc. These bands disappear with age. The underside is whitish.

 

 Aetomylaeus nichofi

 

 

Family : Torbedinidae

Narcine timlei (Bloch and Schneider, 1801)

Common name : Electric ray
Vernacular name Minsara thirukkai

1. Two large kidney- shaped electric organs in the front part of the disc on either side of head, the eyes are quite small.
2. Dorsal surface spotted against a brown background pale below.

 

 

Colour: The whole body and fins brown or reddish – brown scattered brown spots. Five large brown blotches on each side of pectoral fin.

Narcine timlei

 

 

BONY FISHES (OSTEICHTHYES)

1. Order : Elopiformes
         Family : Elopidae
Elops machnata (Forsskal, 1775)

Common name : Tenpounder
Vernacular name : Allathi

1. A gular plate present between arms of lower jaw, branchiostegal rays very numerous
2. No spines in fins, dorsal fin origin a little behind mid point of body, scales very small.

 

Colour: Back blue/ green, sides silvery with a yellow tinge, fins faint yellow

Elops machnata

 

Family : Megalopidae

Megalops cyprinoides (Broussonet, 1782)

Common name : Tarpon
Vernacular name: Morakkai

1. Lower jaw projecting a gularplate present between arms of lower jaw.
2. Last dorsal fin ray filamentous, scales large.

 

 

 

Colour: Back blue, green, flanks silvery.

Megalops cyprinoides

 

2. Order : Anguilliformes
Family : Anguillidae

Anguilla bicolor bicolor (Mc Clelland, 1844)

Common name : Eelfish
Vernacularname: Vilangumeen

1. Dorsal fin origin above anus or very nearly so.
2. Lower jaw longer than upper, projecting; angle of mouth a little behind near margin of eye.

 

 

Colour: Olive to dark bluish – brown above, in migratory phase the colour changes to bronze-silver, especially below and the pectoral fins darken.
 

Anguilla bicolor bicolor

 

Family : Ophichthidae

Pisodonophis boro (Hamilton - Buchanan 1822)

Common Name : Bengal snake eel
Vernacular Name : Vilangumeen

1. Dorsal fin originating about a pectoral fin length behind tips of pectoral fins.
2. Pelvic fin absent, vertebrae 171 to 173.