The Gasterosteiformes: A renaissance for bony armor By Christopher Bertram and, 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 7pgsS4http:// 7pgsS4 L94tDMhttp:// L94tDM

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 RKrw7Sk&feature=related

Family Syngnathidae Pipefishes Polyandrous mating system –One female, several males External attachment of eggs to the male Offspring are born free- swimming -Hrw7gaHQ&feature=relatedhttp:// -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 i44k&feature=relatedwww.youtube.com/watch?v=DK9_yuo i44k&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?