Amphioxiformes: Branchiostomatidae

1. Lancelets Amphioxiformes: Branchiostomatidae * branchio = gill (G) * stom = mouth (G)

2. Hagfishes Myxiniformes: Myxinidae myxin = slime (G)

3. Lampreys Petromyzontiformes: Petromyzontidae petra = stone (L) + myzo = to suckle (G) + odontos = teeth (G)

4. 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

5. 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

6. Chimaeras Chimaeriformes: Chimaeridae * single gill opening rather than multiple

7. 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.

8. Carpet Sharks Orectolobiformes: Ginglymostomatidae – Nurse Sharks ginglymo = hinge (G) stom = mouth (G)

9. Carpet Sharks Orectolobiformes:Stegostomatidae– Zebra Sharks Stegos = roof, house, from; stegein = to cover (G) stoma = mouth (G)

10. Carpet Sharks Orectolobiformes: Rhincodontidae– Whale Sharks rhyngchos = snout, muzzle (G) + odous, odontos = tooth, teeth (G)

11. 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)

12. Requiem Sharks Carchariniformes: Scyliorhinidae– Cat Sharks skylla = a shark (G) + rhinos = nose (G)

13. Requiem Sharks Carchariniformes: Triakidae– Hound Sharks Triakis = thrice (G)

14. Requiem Sharks Carchariniformes: Carcharinidae– Requiem Sharks, Tiger Sharks, Reef Sharks karcharos = cutting, sharp, also a kind of shark (G) + rhinos = nose (G)

15. Requiem Sharks Carchariniformes: Sphyrnidae– Hammerhead Sharks sphyr = hammer (G)

16. 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

17. Mackerel Sharks Lamniformes: Lamnidae– Mackerel Sharks lamna = shark (G)

18. Mackerel Sharks Lamniformes: Cetorhinidae– Basking Shark cetus = whale, marine monster (L) + rhinos = nose (G)

19. Mackerel Sharks Lamniformes: Odontaspididae– Sand Tiger Shark odont = teeth (G) aspid = viper (G)

20. 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

21. Dogfish Sharks Squaliformes: Squalidae– Dogfishes squaleo, squalidus = with rough skin (L)

22. Dogfish Sharks (Squaliformes: Somniosidae)– Sleeper Sharks Now Squaliformes: Dalatiidae dalos, -ou = torch (G)

23. Skates & Rays (Batoids) Rajiformes: Pristidae now Pristiformes:Pristidae • 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)

24. Skates & Rays Rajiformes: Pristidae– Sawfishes prist = sawed (G)

25. 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

26. Skates & Rays Rajiformes: Torpedinidae– Electric rays torped = numb, paralysis (L)

27. 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

28. Skates & Rays Rajiformes: Rajidae– Skates Raja = ray (L)

29. 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

30. Skates & Rays Rajiformes: Dasyatidae– Stingrays dasys = hair (G)

31. Skates & Rays Rajiformes: Gymnuridae– Butterfly Rays gymnos = naked (G) + uro = tail (G)

32. Skates & Rays Rajiformes: Myliobatidae– Eagle Rays myleys = mill, millstone (G) + batis = ray (G)

33. Skates & Rays (Rajiformes: Mobulidae– Manta Rays) Now lumped with Myliobatidae

34. Coelacanth Coelacanthiformes: Coelacanthidae– Coelacanths coel = hollow (G) acanth = spine (G)

35. Lungfish Lepidosireniformes: Protopteridae– African Lungfish pro = before, in front of (G) + pteron = fin (G)

36. Reedfishes & Bichirs Polypteriformes: Polypteridae– Bichir poly = many (G) pteri = fin (G)

37. Sturgeons & Paddlefishes Acipenseriformes: Acipenseridae– Sturgeons acipenser = sturgeon (L)

38. Sturgeons & Paddlefishes Acipenseriformes: Polyodontidae– Paddlefishes poly = many (G) odont = teeth (G)

39. Gars Semiontiformes: Lepisosteidae– Gars lepis, -idos = scale (G) + osteon = bone (G)

40. Bowfin Amiiformes: Amiidae amia = A kind of fish, probably the perch or the bonito (G)

41. Bonytongues Osteoglossiformes: Osteoglossidae– Bonytongues osteon = bone (G) + glossa = tongue (G) + forma = shape (L)

42. Bonytongues Osteoglossiformes: Pantodontidae– Butterflyfishes pan = all (G) + odous = tooth, teeth (G)

43. Bonytongues Osteoglossiformes: Notopteridae– African Knifefishes noton = back (G) + pteron = wing, fin (G)

44. Bonytongues Osteoglossiformes: Mormyridae– Elephantnose Fishes mormyros = a kind of fish (G)