WFB 232 Ichthyology
Taxonomy, Week 4
14 Feb 2005
SUPERCLASS GNATHOSTOMATA
CLASS ACTINOPTERYGII
Subclass Neopterygii
Division Teleostei
38 Orders, 425 Families, and 4,070 genera
“lower lobe of the caudal fin primitively supported by two hypurals articulating from a
single centrum” Patterson, 1968. i.e. the lower lobe of the caudal fin has 2 muscles & associated
fin rays emerging from a single point at the base of the tail.
Other characteristics: no ganoid scales, no spiral valves, pectoral fins generally set higher on body,
enabling better mobility.
Subdivision Osteoglossomorpha (bonytongues, elephantfish, featherbacks, mooneyes)
Order Osteoglossiformes
most primitive living teleosts, have advanced electrical capability, soft connection
between swim bladder and ear
Jurassic/Cretaceous in origin.
In Vermont: Family Hiodontidae, Hiodon tergisus (mooneyes)
Subdivision Elopomorpha (tarpons, bonefishes, eels, gulpers)
mostly marine, diverse body form, 25 familes, ~ 800 spp. identified
larval stage is leptocephalus
Order Elopiformes (tarpons, ladyfishes, tenpounders)
Found in Jurassic, abundant in Cretaceous
gular plate, branchiostegal rays range from 6-36, pelvic rays from 10-18
forked caudal fins
sought after as sportfishes, not necessarily food, range from 1 –2 ½ meters in length
mostly found in warmer marine environments.
Order Anguilliformes (eels - American & European, Conger, slime, sawtooth)
- marine and catadromous, several suborders, anguilliform and filiform shapes
- elongate with large numbers of vertebrae, pectoral girdle not connected to skull,
gas bladder physostomus, pyloric caeca
- in most families, scales and pelvic fins are absent
Family Anguillidae (American and European eels)
Complex life history: spawn in Sargasso Sea, larvae drift for months/years on ocean
currents, then become “glass eels”, at which point they can enter fresh water. They
then metamorphose into pigmented elvers, then move into fresh water, where they feed,
grow, and mature. Mature eels (~4-6 years old) then migrate back to Sargasso Sea to
spawn. Reach ~ 1 meter in length. Other species (A. japonica) in Asia spawn in areas
similar to the Sargasso, with similar life cycles.
In Vermont: American eel (Anguilla rostrata)
Order Saccopharyngiformes (gulpers and swallowers)
eel-like fishes of deep marine waters
lack maxilla, premaxilla, opercular bones and branchiostegals
hyomandibular projects backward, elongating the mouth
some lack gas bladders, scales, & ribs, caudal & pelvic fins are reduced/absent
mouth can be 3-7 times as long as the cranium
feed on other fishes, some species have bioluminescent organs
Subdivision Clupeomorpha
Order Clupeiformes (herrings and anchovies)
Jurassic Period
gas bladder extends into inner ear, soft rays, silvery deciduous scales (cycloid)
planktivorous, lack gular plate
harvested around the world – anchovies in Peru
Family Clupeidae (herrings, shads, sardines)
20 million metric tons harvested annually
marine, anadromous & freshwater
compressiform, teeth small/absent
In Vermont: American shad (Alosa sapidissima)
Alewife (Alosa pseudoharengus)
Blueback herring (Alosa aestivalis)
Gizzard shad (Dorosoma cepedianum)