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The Gasterosteiformes:A renaissance for bony armor
By Christopher Bertramand, also, Kate Laskowski
Superorder Acanthopterygii
Acanthopterygii Traits
• Ascending process– Jaw mobility and
protrusibility
• Pharyngeal dentition– Most developed
• New muscle and bone attachment
• Other– Ctenoid scales– Physoclistous gas
bladder
Series Percomorpha
• Rumored to be most diverse group of fishes– 12,000 spp.
• Defined by anteriorly placed pelvic girdle– Connected to pectoral
girdle via a ligament
• Pelvic fin– Anterior spine– 5 soft rays
Order Gasterosteiformes
• Diversity– 257 spp.
• Habitat– Fresh and saltwater
• Anatomy– Small mouths – Dermal armor
• Almost as good as placoderms
• Highly studied– Behavior – Physiology– Ecology– Evolution
Family Hypoptychidae
• Sand eels• Not true eels• Marine near Japan
and Korea• Important food
source for diving birds
• Burrow into the sand to avoid predation
• Understudied
Family Aulorhynchidae
• Tube snouts• Rigid body with
small dorsal fin• Uneven jerky
movement• Marine species
– West coast of NA– East coast of Asia
• Love kelp
Family Gasterosteidae
• The sticklebacks, AKA the most amazing fish ever!– Threespine– Black-spotted– Nine-spine– Brook– Four-spine– Fifteen-spine
Gasterosteaus aculeatus
• Found all over Northern Hemisphere
• Independently derived freshwater populations = amazing study organism– Especially for behavior!
• Lots of variation in spines and plating– Low plating and smaller
spines selected in freshwater environments
Single dad with 45 kids seeks non-cannibalistic mother
• Males build nests and attract females
• Elaborate courtship dance
• If he’s a hottie, female will dump and run
• Male then:– Fans eggs– Cleans off fungus– Defends against hungry
fish– Fry retrievals
Family Pegasidae
• Seamoths or Pegasus fish
• Quite rare, only 5 spp.• Shed their scales to
prevent parasite build-up
• Can’t really swim so he “walks” using his ultra cool pelvic fins
• http://www.youtube.com/watch?v=6l2d67pgsS4
• http://www.youtube.com/watch?v=FIgBjL94tDM
Family Solenostomidae
• Ghost pipefishes• Marine
– Coastal– Tropical– Reedy area
• Reproduction– Females carry eggs
in brood pouch• Modified pelvic fins
Family Syngnathidae
• Seahorses• Unusual shape• Male parental care
– Only natural male pregnancy in verts
– Evolved multiple
times
– Breeding• Female inserts
ovipositor • Egg shells dissolve• Male placenta
Family Syngnathidae
• Seahorses
• Evolutionary consequences– Females compete
for males– Sexually
dimorphic• In polyandry
www.youtube.com/watch?v=VzwrRKrw7Sk&feature=related
Family Syngnathidae
• Pipefishes• Polyandrous mating
system– One female, several
males
• External attachment of eggs to the male
• Offspring are born free-swimming
• http://www.youtube.com/watch?v=dT-Hrw7gaHQ&feature=related
– (good stuff at 45 s)
Family Indostomidae
• Only 1 genus, 3 species
• Lazy fish• Discovered in 20’s• Distribution
– Marine– Thailand
• Armored body– Covered in scutes
Family Aulostomidae
• Trumpet fishes• One genus, 3
species• Distribution
– Marine– Tropical – Worldwide
• Highly carnivorous– Ambush predator– They suck
Family Fistulariidae
• Cornetfishes• One genus, four
species• Distribution
– Marine– Tropical/sub-tropical
• Predate on invertabrates
• Not of fishing interest, except this guy
• www.youtube.com/watch?v=DK9_yuoi44k&feature=related
Family Macrorhamphosidae
• Snipefishes• Distribution
– Marine– Circum-global– Temperate waters
• Feed on invertebrates– “Anteater of the
sea,”© KL Laskowski
• Size matters
My spine is sooooo big…
Family Centriscidae
• Shrimpfishes• Marine only• Small family
– Approximately 12 spp.
• Indo-pacific distribution
• Anatomy– Unusual– Covered in bony plates– Dorsal fin long/sharp– Fins moved ventrally
Review of Gasterosteiformes
• Generally scale-less– Heavy body armor– Pelvic girdle
• Males finally pull their own weight– Male parental care– Male pregnancy
• Mostly marine, shallow water critters• All predacious
Questions
• What’s so weird about seamoths?• Why are sticklebacks great study
organisms?• Do male seahorses and pipefishes really
become “pregnant”?• Where are all the fins on a shrimpfish
located?• Did anyone take hand-written notes, or
did you just assume this would be posted online?
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