Amphioxiformes: Branchiostomatidae

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Lancelets
Amphioxiformes Branchiostomatidae
branchio gill (G) stom mouth (G)
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Hagfishes
Myxiniformes Myxinidae
myxin slime (G)
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Lampreys
Petromyzontiformes Petromyzontidae
petra stone (L) myzo to suckle (G)
odontos teeth (G)
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Elasmo-sources
Bulleted lists and cladogram that follow
ref Martin, R. Aidan.  2003.  ReefQuest Centre
for Shark Research Home.  World Wide Web
Publication, www.elasmo-research.org/index.html
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Chimaeras
Chimaeriformes Chimaeridae

• Gill cover over the four gills, leaving a single
  opening on each side of the head
• palatoquadrate (upper jaw) is usually fused to
  the cranium
• no spiracle opening behind the eye
• branchial (gill) basket mostly beneath the
  neurocranium (posterior part of the cranium that
  encases the brain)
• teeth relatively few (one pair in the lower jaw
  and two pairs in the upper), occurring as
  mineralized grinding plates
• tooth plate replacement is slow
• no cloaca, but with separate anal and urogenital
  openings
• skin in adults 'naked' (without dermal
  denticles)
• no stomach or ribs
• males - in addition to the pelvic claspers -
  have an accessory clasping organ on the head

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Chimaeras
Chimaeriformes Chimaeridae
single gill opening rather than multiple
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Carpet Sharks
Orectolobiformes

• two, spineless dorsal fins
• a very short, transverse mouth that is well
  anterior to the eyes
• specialized nostrils, with prominent barbels and
  nasoral grooves connecting the nostrils to the
  mouth corners in most forms
• spiracles small to very large, located below the
  eye
• most with small gill slits, with the fourth
  overlapping the fifth and behind origin of the
  pectoral fin
• most species have a caudal fin with an upper lobe
  that is more-or-less in line with the main body
  axis (not tilted upward, as in most other sharks)
  and a poorly-developed lower lobe the order's
  scientific name translates roughly to
  "stretched-out lobe", in reference to the tail
  type characteristic of the group
• 13 genera in 8 families
• Note Whale Sharks, the only fully pelagic
  orectolobid,
• are exceptions to many of these rules.

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Carpet Sharks
Orectolobiformes Ginglymostomatidae Nurse
Sharks
ginglymo hinge (G) stom mouth (G)
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Carpet Sharks
Orectolobiformes Stegostomatidae Zebra Sharks
Stegos roof, house, from stegein to cover
(G) stoma mouth (G)
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Carpet Sharks
Orectolobiformes Rhincodontidae Whale Sharks
rhyngchos snout, muzzle (G) odous, odontos
tooth, teeth (G)
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Requiem Sharks
Carchariniformes

• two dorsal fins (except in the scyliorhinid
  Pentanchus profundicolus, which has only one),
  without spines
• anal fin present
• five gill slits, with the last one to three over
  the pectoral fin base
• eyes with nictitating fold or membrane (moveable
  lower eyelid)
• intestinal valve of spiral or scroll type
• found in virtually every marine habitat, many
  species occur in estuarine areas and a few make
  use of freshwater habitats as well they range
  from coastal areas to the open ocean, in
  temperate to tropical zones of the Atlantic,
  Pacific, and Indian oceans
• at least 49 genera in 9 families (possibly as
  many as 60 genera in 14 families)

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Requiem Sharks
Carchariniformes Scyliorhinidae Cat Sharks
skylla a shark (G) rhinos nose (G)
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Requiem Sharks
Carchariniformes Triakidae Hound Sharks
Triakis thrice (G)
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Requiem Sharks
Carchariniformes Carcharinidae Requiem Sharks,
Tiger Sharks, Reef Sharks
karcharos cutting, sharp, also a kind of shark
(G) rhinos nose (G)
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Requiem Sharks
Carchariniformes Sphyrnidae Hammerhead Sharks

sphyr hammer (G)
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Mackerel Sharks
Lamniformes

• two dorsal fins, without spines
• anal fin present
• five pairs of gill slits, either entirely in
  front of the pectoral fin base or with the last
  two above the pectoral base
• spiracles usually present, small and behind eyes
• eyes without nictitating membrane
• mouth subterminal, jaws extending well behind the
  eyes
• upper teeth well differentiated along the jaws
  forming the so-called "lamnoid dental pattern"
  which features enlarged anterior teeth, slightly
  to much smaller intermediate teeth, large lateral
  teeth, followed by much smaller posterior teeth
• intestinal valve of ring type
• exclusively marine, in coastal to open-ocean
  environments they inhabit cold temperate to
  tropical zones of the Atlantic, Pacific, and
  Indian Oceans
• 10 genera in 8 families

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Mackerel Sharks
Lamniformes Lamnidae Mackerel Sharks
lamna shark (G)
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Mackerel Sharks
Lamniformes Cetorhinidae Basking Shark
cetus whale, marine monster (L) rhinos nose
(G)
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Mackerel Sharks
Lamniformes Odontaspididae Sand Tiger Shark
odont teeth (G) aspid viper (G)
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Dogfish Sharks
Squaliformes

• five pairs of gill slits
• two dorsal fins, often with a spine along the
  leading edge the first dorsal originates in
  front of pelvic fin origins
• lack of an anal fin 
• many species are bioluminescent to some degree
• ovoviviparous 
• exclusively marine most species are strongly
  bottom oriented, although many mesopelagic forms
  undertake nightly vertical migrations a
  successful and widely distributed group,
  dogfishes inhabit coastal and oceanic waters,
  mostly in cool temperate to deep tropical waters
  in both hemispheres, but ranging from the
  Antarctic to the Arctic
• 22 genera in 6 families

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Dogfish Sharks
Squaliformes Squalidae Dogfishes
squaleo, squalidus with rough skin (L)
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Dogfish Sharks
(Squaliformes Somniosidae) Sleeper Sharks Now
Squaliformes Dalatiidae
dalos, -ou torch (G)
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Skates Rays (Batoids)
Rajiformes Pristidae now PristiformesPristidae

• snout saw-like with equal-sized,
  strongly-embedded teeth along margin nasal
  barbels absent
• body shark-like
• two distinct dorsal fins and a caudal fin
• ovoviviparous
• mostly marine, although the largetooth sawfish
  (Pristis microdon) ascends some rivers in
  Australia and New Guinea
• 2 genera (Pristis and Anoxypristis) in the family
  Pristidae

prist sawed (G)
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Skates Rays
Rajiformes Pristidae Sawfishes
prist sawed (G)
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Skates Rays
Rajiformes Torpedinidae or Torpediniformes
Torpedinidae

• rounded snout and pectoral disc
• large, kidney-shaped electrogenic organs (derived
  from branchial musculature) at base of pectoral
  fins
• body thick and flabby, with soft, loose skin
• eyes small to obsolete (four species are blind)
• 0 to 2 dorsal fins, depending upon species
• caudal fin well developed
• ovoviviparous
• exclusively marine, inhabiting temperate to
  tropical zones of the Atlantic, Pacific, and
  Indian oceans
• 11 genera in 4 families

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Skates Rays
Rajiformes Torpedinidae Electric rays
torped numb, paralysis (L)
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Skates Rays
Rajiformes Rajidae

• snout pointed
• pectoral disc usually rhomboid
• tail slender, set off from pectoral disc
• caudal fin moderately well developed, reduced or
  absent weak electrogenic organs at base of tail
  stalk (derived from caudal peduncle muscles)
• 0 to 2 dorsal fins
• most with enlarged, thorn-like denticles
  ('bucklers') on skin, often with a row along
  midline of back 
• oviparous 
• almost exclusively marine a few species live in
  shallow waters close to shore, but most live in
  deep water, on soft bottoms along continental
  margins, down to 8 840 feet (3 000 metres) or
  more 
• 26 genera in a single family (Rajidae), divided
  into 2 subfamilies

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Skates Rays
Rajiformes Rajidae Skates
Raja ray (L)
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Skates Rays
Order Myliobatiformes Stingrays - 178 species

• pectoral disc rhomboid, oval, or triangular in
  outline, elaborated into gracefully-shaped wings
  in some forms 
• tail moderately stout to very slender 
• caudal fin and a single dorsal fin are variably
  present or absent, depending on species 
• most species have one or more saw-edged spines or
  stings on the dorsal surface of the tail (the
  sting is a modified dermal denticle, sheathed
  with poisonous tissue and used as a defensive
  weapon)
• most forms have five pairs of gill slits, but
  members of the family Hexatrygonidae have six
• ovoviviparous 
• temperate to tropical zones of the Atlantic,
  Pacific, and Indian oceans most species are
  marine, but some enter brackish or fresh waters
  and the river stingrays (family Potamotrygonidae)
  are exclusively freshwater inhabitants, having
  lost the ability to osmoregulate in the sea 
• 33 genera in 10 families

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Skates Rays
Rajiformes Dasyatidae Stingrays
dasys hair (G)
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Skates Rays
Rajiformes Gymnuridae Butterfly Rays
gymnos naked (G) uro tail (G)
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Skates Rays
Rajiformes Myliobatidae Eagle Rays
myleys mill, millstone (G) batis ray (G)
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Skates Rays
(Rajiformes Mobulidae Manta Rays) Now lumped
with Myliobatidae
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Coelacanth
Coelacanthiformes Coelacanthidae Coelacanths
coel hollow (G) acanth spine (G)
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Lungfish
Lepidosireniformes Protopteridae African
Lungfish
pro before, in front of (G) pteron fin (G)
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Reedfishes Bichirs
Polypteriformes Polypteridae Bichir
poly many (G) pteri fin (G)
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Sturgeons Paddlefishes
Acipenseriformes Acipenseridae Sturgeons
acipenser sturgeon (L)
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Sturgeons Paddlefishes
Acipenseriformes Polyodontidae Paddlefishes
poly many (G) odont teeth (G)
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Gars
Semiontiformes Lepisosteidae Gars
lepis, -idos scale (G) osteon bone (G)
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Bowfin
Amiiformes Amiidae
amia A kind of fish, probably the perch or the
bonito (G)
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Bonytongues
Osteoglossiformes Osteoglossidae Bonytongues
osteon bone (G) glossa tongue (G) forma
shape (L)
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Bonytongues
Osteoglossiformes Pantodontidae
Butterflyfishes
pan all (G) odous tooth, teeth (G)
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Bonytongues
Osteoglossiformes Notopteridae African
Knifefishes
noton back (G) pteron wing, fin (G)
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Bonytongues
Osteoglossiformes Mormyridae Elephantnose
Fishes
mormyros a kind of fish (G)