Time range of Hexanchiformes species

The shark order Hexanchiformes (in a broad sense, not only comprising the cow sharks, but also including the frilled sharks, Chlamydoselachidae) is often considered the most primitive of extant sharks, since they share some features with Paleozoic and early-Mesozoic shark groups as the Cladoselachiformes. Thus, it is interesting to see how far back the fossil record of this order reaches.

Family Chlamydoselachidae

Species

Lower Cretaceous

Upper Cretaceous

Paleocene

Eocene

Oligocene

Miocene

Pliocene

Pleistocene

Holocene

Extant

B

V

H

B

A

A

C

T

C

S

C

M

D

S

T

Y

L

B

P

R

C

A

B

L

S

T

M

Z

P

G

L

M

U

Chlamydoselachus thomsoni[1]

Chlamydoselachus gracilis[2]

Chlamydoselachus goliath[2]

Proteothrinax baumgartneri

Chlamydoselachus fiedleri

Chlamydoselachus tobleri

.

Chlamydoselachus bracheri

Chlamydoselachus lawleyi

Chlamydoselachus anguineus

Family Hexanchidae

Species

Lower Cretaceous

Upper Cretaceous

Paleocene

Eocene

Oligocene

Miocene

Pliocene

Pleistocene

Holocene

Extant

B

V

H

B

A

A

C

T

C

S

C

M

D

S

T

Y

L

B

P

R

C

A

B

L

S

T

M

Z

P

G

L

M

U

Heptranchias howellii

.

Heptranchias ezoensis

Heptranchias tenuidens

Heptranchias perlo

.

.

-

-

-

-

-

-

Genus

Species

Early Jurassic

Middle Jurassic

Upper Jurassic

Lower Cretaceous

Upper Cretaceous

Paleocene

Eocene

Oligocene

Miocene

Pliocene

Pleistocene

Holocene

Extant

H

S

P

T

A

B

B

C

O

K

T

B

V

H

B

A

A

C

T

C

S

C

M

D

S

T

Y

L

B

P

R

C

A

B

L

S

T

M

Z

P

G

L

M

U

Hexanchus

arzoensis

microdon “agassizii”

.

.

.

.

gracilis

collinsonae

hookeri

agassizi

.

griseus

.

-

-

-

-

-

-

-

-

-

-

-

-

-

nakamurai “vitulus”

griseus “andersoni” “gigas"

.

Notidanoides

-

.

-

-

-

-

-

-

-

-

-

-

-

Notidanodon

lanceolatus

.

-

antarcti

dentatus

pectinatus

brotzeni”

loozi”

Notorynchus

“Notidanus” aptiensis”

“Notidanus” intermedius

“Notidanus” lawleyi

“Notidanus” munsteri

“Notidanus” cepedianus “primigenius” “kempi”

.

.

.

“Notidanus” serratissimus

“Notidanus” serratus