Ammonites nyob rau lub sijhawm ntawm Ntiaj Teb keeb kwm hu ua the Jurassic thiab Cretaceous. Ua ke, cov no sawv cev rau lub sijhawm luv ntawm txog 140 lab xyoo. Lub Sijhawm Jurassic tau pib txog 201 lab xyoo dhau los thiab Cretaceous Lub Sijhawm xaus li 66 lab xyoo dhau los.
Lub sijhawm twg yog cov pob txha ammonite pom nyob hauv?
Ammonite yog lo lus hais txog ammonoids, ib pawg loj thiab ntau haiv neeg uas tshwm sim thaum lub sijhawm Devonian, uas pib txog 416 lab xyoo dhau los. Ammonoids muaj feem xyuam rau lwm yam cephalopods-xws li squid, octopuses, thiab cuttlefish-thiab lawv yog cov txheeb ze ntawm cov nautilus niaj hnub no.
Cov ammonite nyob hauv ntiaj teb tau pes tsawg xyoo?
Ammonites tau txav los ntawm lub dav hlau propulsion, tshem dej los ntawm qhov qhib zoo li funnel kom txav lawv tus kheej mus rau qhov sib txawv. Lawv ib txwm nyob tau ob xyoos, txawm tias qee hom muaj sia nyob dhau qhov no thiab loj hlob zoo li daim duab saum toj no.
pom ammonite nyob qhov twg?
Thiab thaum cov qauv tau pom yuav luag txhua qhov chaw ntawm lub ntiaj teb, Antarctica yog qhov paub zoo rau nws qhov chaw nplua nuj ammonite fossil. Ntawm cov hom ammonite txawv tshaj plaws uas pom nyob rau hauv Antarctica yog Diplomoceras cylindraceum, uas tuaj yeem loj hlob mus txog 2 meters ntev thiab tau sau tseg rau nws cov ntawv-puab-puab, lub plhaub uncoiled.
Puas yog ammonites laus dua dinosaurs?
Nws tsis yog cov dinosaurs uas tau ploj mus 65 lab xyoo dhau los. Ammonites, ib hom ua ntej keeb kwm ntawm marine mollusc, muaj ntau tshaj li 300 lab xyoo. Lawv los ntawm lub sijhawm Devonian mus rau qhov kawg ntawm Cretaceous system, thaum lawv tau ploj mus ib yam li cov dinosaurs.
