presentation will give idea on the taxonomic characters of cephalopods

1. CEPHALOPOD
TAXONOMY
Presented by;
Suraj Kumar Pradhan
FRM-MA5-01

2. CLASSIFICATION OF MOLLUSC..
Phylum Mollusca is classified into seven classes;
 GASTROPODA (single shelled cowries, cones etc)
 BIVALVIA ( two shelled like clams, mussels etc)
 APLACOPHORA (solenogasters)
 MONOPLACOPHORA (segmented limpets)
 POLYPLACOPHORA ( or Amphineura as it was earlier
called- Chitons)
 SCAPHOPODA (tusk shells)
 CEPHALOPODA (nautilus, squids, Cuttelfish, octopus
etc)

3. CEPHALOPODS..
 Greek (kephalópoda); "head-feet“
 exclusively marine
 The study of cephalopods is a branch of malacology.
 Cephalopods became dominant during the Ordovician
period, represented by primitive nautiloids.

4. CHARACTERS OF CEPHALOPODS
 Much advanced groups.
 800 species of all over the world.
 Exclusively marine species.
 Bilaterally symmetrical.
 Shell spirally chambered,usually with or without shell
embedded in mantle.
 Body may be globular or oval or arrow shaped and have fins on
the sides.
 Body devided into head and trunk.
 Head bears a pair of large lateral eyes and mouth.mouth bears
jaws and radula.
 Trunk consists of symmetrical and uncoiled visceral mass.

5. CON...
 Foot altered into a series of large prehensile suckers bearing
arms of tentacles encircling mouth.
 Fin inserted laterally may surround the body(cuttle fish) or
devided into two lateral fins placed more or less
posteriorly(squids).
 Excreatory system consists of 2-4 pairs of nephridia.
 Nervous system highly developed and sexes separate.
 Last pair of tantacles has raproductive organ(like bulk of
grape).

6. CON...
 an internal shell,dorsal in position either calcified or
horny and transparent (pen or gladius in squid and
cuttlebone in cutttle fish).In octapoda the shell is reduced
to a plate of connective tissues.
 Cephalopods lacerete their pray with their parrot beak
formed by a dorsal and a ventral mandible.
 Devided into three sub-classes;
Sc-1 – coleoidea or dibranchiata
Sc-2 – nautiloidea or tetrabranchiata
sc-3 - ammonoidea

8. SUB-CLASS 1 –COLEOIDEA OR DIBRANCHIATA
 Shell internal,embedded in tissue,
calcareous,chitinous or cartilaginous.
 8 or 10 circumoral appendeges with suckers.
 Only one pair of gills,funnel and tube like.
 Ink glands and chromatophore present.
 Devided into 4 orders;
a) sepioidea
b) teuthoidea(squids)
c) octapoda
d) vampyromorpha

9. FAMILY IDENTIFICATION.......
1. Cephalopods with eight circumoral arms, without tentacles; arm
suckers arranged in two rows, without horny rings and stalks. Third
arm tip of male spoon-shaped (hectocotylized)
......................................................................(Octopodidae) Octopus.
Cephalopods with ten arms eight being short and circumoral and two
slender and tentacular. Suckers of the arms and tentacles stalked and
equipped with armature
......................................................................... 2
2. Shell (cuttlebone) internal calcareous in nature, body ovoid and
dorsoventrally somewhat flattened. Fins narrow, marginal in position
and extending on either side along the entire length of the mantle, not
uniting at the end. Arms with mostly quadriserial suckers... (Sepiidae)
.................................. 3
Shell (gladius or pen) internal but chitinous in nature. Body
cylindrically elongate. Fins either terminal or marginal in position
uniting at the apex of the mantle
.................................... 4

10. CON..........
3. Cuttlebone broadly oval in shape and with a spine at the posterior
end. The mantle without a glandular pore at the posterior extremity
.................Sepia (S aculeata) and S. Pharaonis)
Cuttlebone smaller in size, oval in shape and devoid of the spine.
The mantle bears a small but distinct glandular pore at the posterior
extremity......................................... Sepiella
4. Fins triangular or rhomboidal in shape, restricted to the posterior
margin of the mantle ...................Loligo (Loligo duvauceli)
Fins broad and extending almost to the entire length of the mantle
........................................Sepioteuthis (Sepioteuthis arctipinnis)

11. ORDER - SEPIODEA
 Internal shell (sepion) calcareous and either straight and
laminated or coiled and chambered or absent.
 Eyes covered with skin and supplementary eyelid
present.
 8 sessile arms.
 2 tentacular arms contractile and retractile into pockets.
 Suckers without stalks.
 Fin lobes free posteriorly.

12. FAMILY - SEPIIDAE
 Body either elongate or broad or very slender
and dorsoventrally flattened.
 Fins marginal and narrow,extending all along
mantle on either side.
 Internal shell(sepion) present.
 Light organds absent.
 S. pharaonis, S. prashadi, S. aculeata, S.
brevimana, S. elliptica, S. arasica, S. trygonina

13. KEY TO GENERA..
 Cuttlebone calcified only in posterior half, anterior half chitinous….
Hemisepius .
 Cuttlebone entirely calcified;
 Cuttlebone with spine present on posterior end; no glandular pore on ventral
surface at posterior end of mantle…. Sepia.
 Cuttlebone without spine present on posterior end; glandular pore on ventral
surface at posterior end of mantle…. Sepiella.

14. SEPIA PHARAONIS (EHRENBERG)
 The body of the cuttlefish is stout
and oval in outline and widest at
the anterior end. In front, the
mantle is produced middorsally into
a triangular lobe and midventrally
slightly emarginated
 Fins very wide and fleshy and
originate a few millimetres behind
the anterior margin of the mantle;
fins broad, extend along the
periphery of the mantle and reach
the posterior extremity; funnel large
and thick walled, reaching almost
to the base of the ventral arms; a
triangular valve present in the
funnel.

15. SEPIA ACULEATA (FFERUSSAC AND
D'ORBIGNY)
 The mantle is roughly oval,
broadest near the anterior end;
ventral margin of the mantle
concave in the middle, middorsal
projection has well-excavated
sides.
 Fins narrow and originate a little
behind the anterior margin of the
mantle on the sides and extend to
the end of the body where they are
almost in contact with each other;
head narrower than mantle
opening ; funnel short and does
not reach the base of the ventral
arms; buccal lappets surrounding
mouth are seven, with minute
suckers at their extreme ends

16. SEPIA BREVIMANA
 Tentacular clubs short with 6-8
small subequal suckers.
Cuttlebone flat and distinctly
acuminate anteriorly, dorsal
surface rugose, a shallow median
groove in the striated area.
 The striae ' A ' shaped with a
median shallow groove
broadening anteriorly ; inner cone
and its limbs pinkish in colour;
spine small, sharp and slightly
curved.

17. SEPIA ELLIPTICA
 Tentacular clubs moderately
long, with 10 rows of small
suckers of uniform size.
Cuttlebone thin, elliptical in
shape, dorsal surface smooth ;
two conspicuous lateral ridges
more prominent anteriad
resulting in three longitudinal
furrows in striated area ; spine
thick, sharp, long and well
curved.

18. SEPIA TRYGONINA
 No fleshy projections on
head', fins extend upto end of
mantle ; tentacles with short
clubs, suckers in eight rows,
about five in third row
enlarged.
 Cuttlebone lanceolate with
acuminate anterior tip with
edges of outer cone winged
giving an arrow head
appearance; spine small.

19. ORDER – TEUTHOIDEA(SQUIDS)
 Internal shell(gladius or pen) chitinous,feather or
rod shaped.
 8 sessile arms.
 2 tentacular arms contractile but not
retractile,pockets absent.
 Suckers stalked and with or without hooks.
 Finlobes fused posteriorly

20.  Suborder – myopsida(neretic squid)
eyes completely covered with a corneal membrane.
Family- Loliginidae
Loligo duvauceli, L.uyii, Doryteuthis
singhalensis, D. sibogae, Sepiotuthis lessoniana,
Loliolus investigatoris

21.  Suborder – oegopsida(oceanic squid)
eyes not covered with a corneal membrane and open to
the surrounding medium.
Family-Onchoteuthidae (Onchoteuthis banksi)
Family- Ommustrephidae (Ommustrephes bartrami,
Symplectiteuthis oualaniensis)
Family- Thysanoteuthidae (Thysanoteuthis rhombus)

22. KEY TO GENERA..
 Vane of gladius broad, with thin,
curved edges ; posterior end of
mantle moderately blunt; mantle
not very narrow in males; fins
usually less than 70% of mantle
length…… subgenus Loligo
 Vane of gladius narrow, with
thick, straight edges ; posterior
end of mantle relatively pointed;
mantle very narrow in males;
fins usually more than 70% of
mantle length……subgenus
Doryteuthis
vane

23. LOLIGO UYII
 Body short and stout; mid-
rib of gladius clearly visible
through dorsal mantle skin
as a median dark line.
 Fins 55-65 per cent of
mantle length ; Tentacular
clubs large median manal
suckers with smooth rings.
 In males left ventral arm
hectocotylized almost the
entke arm ; papillae on
ventral margin fused with
membrane.. • • •

24. SYMPLECTOTEUTHIS OUALANIENSIS
 Funnel and mantle cartilages of
the locking apparatus fused
together.
 An oval photophoric pateh
present middorsally near
anterior margin of mantle.
 Muscle of mantle ventrally
without embedded light organs;
two intestinal photophores
present

25. DORYTEUTHIS SINGHALENSIS
 Mantle very long and stendo-
with a ridge along midline in
males; fins wide and long and
more than 60 per cent of
mantle length; half of left
ventral arm heterocotylized
used distally in males.
 gladius narrow with almost
straight margins and tapering
gradually to a narrow point.

26. LOLIGO DUVAUCELI
 This is a common Indo-Malayan species occurring
from South Africa to Formosa (Voss, 1963).
 In India it is commonly found on the east and
west coasts
 The mantle is slender and tubular in outline and
tapers gradually from about the middle to a blunt
posterior end; the fins are smaller and rhomboidal
in shape.
 The narrow head possesses ten arms including
the two long slender tentacles. Sessile arms
usually in the order 3.4.2.1. in length; suckers
arranged in two rows in all arms;
 Chitinous rings of the arm suckers possess about
6 to 8 teeth and sometimes more as in the case of
larger suckers of males; tentacular clubs bear four
rows of suckers, the rings of which are equipped
with 17 to 20 teeth; distal half of the left arm of the
male is hectocotylized;
 The gladius is narrow and slightly brownish in
colour; the ink sac possesses two small light
organs one on either side.

27. ORDER - OCTAPODA
 Internal shell and nidamental gland absent.
 Body rounded or oval and with no lateral fins.
 8 arms;suckers without stalks and without
chitinous ring.
 Tentacles absent.
 Light organ absent.

28. FAMILY - OCTOPODIDAE
 Octopus have 8 arms.
 Without an external shell.
 Internal shell either vestigial or lacking.
 Great disparity seen in males and females in size and benthic in
habitat.
 2 suborder – cirrata and incirrata
 Sub order – Incirrata
 Family – Octopodidae
 Octopus dolfusi, O. aegina, Cistopus indicus
Hapalochlaena maculso, Berrya keralensis
 Family – Argonautidae (fragile shell paper nautilus)
Argonauta argo, A. hinas.

29. OCTOPUS VULGARIS
 Body distinctly warty, up
to 1000 mm total length,
with maximum arm
spread of 3000 mm, but
commonly much smaller.
 Arms are thick and stout,
bearing two longitudinal
rows of suckers. Arm
length is 70-85 % of total
length.

30. OCTOPUS MEBRANACEUS
 8 arms;suckers without
stalks and without
chitinous ring.
 Tentacles absent.
 Light organ absent

31. ORDER – VAMPYROMORPHA
 Physically, they somewhat resemble octopuses, but
the eight main tentacles are united by a web of
skin, and two smaller tentacles are also present.
(Vampyroteuthis infernalis)

32. SUBCLASS 2- NAUTILOIDEA
Shell external,coiled
and chambered,more
than 10(63 to 94)
circumoral
appendeges without
suckers.
2 pairs of gills.
Ink glands and
chromatophores
absent.
eg; nautilus pompilius
endoceras

33. SUB-CLASS 3 - AMMONOIDEA
 Shell is external,coiled.
 Syphon is external.
 Extinct forms of mesozoic era.
eg; ammonites

35.  Class: Cephalopoda
 Subclass: Nautiloidea
 Family: Nautilidae, e.g.
Nautilus pompilius
 Subclass: Ammonoidea
(Ammonite relatives, extinct)
 Subclass: Coleoidea
 Superorder: Octopodiformes
 Order: Vampyromorpha
 Family: Vampyroteuthidae
 Order: Octopoda
 Suborder: Cirrata
 Suborder: Incirrata
 Tribus: Argonautida
 Family: Alloposidae
Family: Argonautidae, e.g.
Argonauta argo,
Family: Ocythoidae
Family: Tremoctopodidae
 Tribus: ----
 Family: Amphitretidae
Family: Octopodidae,
Family: Vitreledonellidae
Family: Bolitaenidae
 Superorder: Decapodiformes
 Order: Teuthida
 Suborder: Oegopsida
 Family: Architeuthidae,
 Suborder: Myopsida
 Family: Loliginidae,
Family: Chtenopterygidae
Family: Bathyteuthidae
 Order: Sepiida
 Family: Sepiidae,
Family: Spirulidae
Family: Idiosepiidae
Family: Sepiadariidae
Family: Sepiolidae