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?