WFB 232 Ichthyology
Myxiniformes
Taxomony:Superclass Agnatha– jawless fishes
Class Myxini - hagfishes
Order Myxiniformes
Family Myxinidae
5 genera, ~ 40 species
Description:most primitive vertebrates: degenerate eyes, cartilaginous skeleton, no vertebrae, no lateral line, jawless, anguilliform shape
gill openings, no paired fins; vestigial caudal fin; 3 pairs of barbels around mouth
isoosmotic (body fluids at same salinity as ocean)
no larval stage (that has been found)
structurally, but not functionally, hermaphroditic
Habitat: Mostly soft bottom habitat
Distribution: marine, temperate zone, intertidal to 5,000 m, mostly 25-1,500 m depths
Ecology and life history: little known of life cycle; produce few, large eggs
scavengers on dead fish; remove flesh with toothed tongue, may slide a knot along their body to apply pressure on carcass
burrow in soft sediments; often found within fish carcasses
Additional details: Economically important, used for leather and food in Asia
Exude extremely large quantities of slime (“myxin”)
First fossil evidence: Carboniferous, ~340 – 290 MYA
References used:
Bond, C. E. 1996. Biology of Fishes, 2nd. ed. SaundersCollege Publishing, Fort Worth
Moyle, P. B. and J. J Cech. 2000. Fishes, an Introduction to Ichthyology. Prentice Hall
Paxton, J. R. and W. N. Eschmeyer. 1998. Encyclopedia of fishes 2nd ed. Academic Press.
Petromyzontiformes
Taxonomy:Superclass Agnatha - jawless fishes
Class Cephalaspidomorphi
Order Petromyzontiformes - lampreys
Families Petromyzontidae
8 genera, ~ 40 species
VT species: Ichthyomyzon – single dorsal fin (silver lamprey, brook lamprey)
Petromyzon – two dorsal fins (sea lamprey)
Lampetra – fewer circumoral teeth (brook lamprey)
Description: primitive, jawless, cartilaginous, anguilliform fishes with no scales or paired fins, one or two dorsal fins and caudal fin, gill pores or slits; vertebrae present
Larvae are a few centimeters long, lack well-developed eye; adults may reach 0.6 m
Mouth of adults is a suction disk with circumoral teeth for attachment, and a few, large, rasping teeth on a ‘tongue’
Unlike Myxini, they have two semicircular canals, lateral line system, well developed eyes in adults
Habitat: Anadromous or in streams
Distribution: N. and S. America, Australia, New Zealand, Europe
Ecology and life history: Long larval stage (ammocoetes) in freshwater streams (2-7 years), followed by short adult stage in fresh or salt water (1 month - 2 years)
Highly fecund (60,000 -300,000 eggs)
Larval forms generally detritus feeders; adults may be parasitic on fish, or non-feeding
Parasitic species undergo metamorphosis, feed in fresh or salt water as juveniles, then return to streams as adults to spawn.
Non-parasitic species are stream-resident, do not feed after metamorphosis, and spawn soon after metamorphosis
Parasitic form appears to be the ancestral type
Some Australian species are predatory rather than parasitic
Additional details: parasitic sea lamprey (Petromyzon marinus) invaded the Great Lakes, has become land-locked, and has caused major economic and ecological damage to fisheries.
References used:
Bond, C. E. 1996. Biology of Fishes, 2nd. ed. SaundersCollege Publishing, Fort Worth
Paxton, J. R. and W. N. Eschmeyer. 1998. Encyclopedia of fishes 2nd ed. Academic Press.
Anatomy assignment
Briefly define the following, or describe where in a fish you would find it:
e.g. hemal arch: “on ventral side of caudal vertebrae”, or “arch of bone on ventral surface of caudal vertebrae”
maxilla
nares
pelvic fins
ceratotrichia
adipose fin
hypaxial muscles
hypurals
operculum
otoliths
pterygiophores
cleithrum
centrum
On what kind of fish would you find placoid scales?
What is the function of the zygopophysis and basapophysis?
Fill in the names of the anatomical parts indicated on the diagrambelow:
Suggested resources: Cailliet, G., M. Love, and A. Ebeling. 1996. Fishes: a field and laboratory manual on their structure, identification, and natural history. Waveland Press, Inc., Prospect Heights, IL
Josh Ashline / Gasterosteiformes – Gasterosteidae, PegasidaeJeffrey Auger / Gasterosteiformes – Syngnathidae, Indostomidae
Steven Brown / Perciformes – Centrarchidae, Percidae, Percicthyidae
Sarah Goodrich / Perciformes - Sciaenidae
Lauren Hahl / Perciformes - Mullidae
Anna Johnson / Perciformes - Cichlidae
Garret Langlois / Perciformes - Mugilidae
Meaghan Linehan / Perciformes – Gobiidae
Kayla Malzac / Perciformes – Serranidae
Andrew Menke / Perciformes – Pomacentridae
Erika Partee / Perciformes – Chaetodontidae, Acanthuridae
Tracy Sylvester / Perciformes - Scombridae
Neil Thompson / Perciformes – Labridae, Scaridae
Haley Zdyrko / Perciformes - Blenniidae
Jake Riley / Pleuronectiformes
Wayne Bouffard / Tetraodontiformes – Balistidae, Ostraciidae
Matt Neilsen / Tetraodontiformes – Tetraodontidae, Molidae