Fossil = Pre-evolved form = post-evolved form
Helix Fossil = Omanyte = Omastar
Dome Fossil = Kabuto = Kabutops
Stats: HP Atk Def Sp.Atk Sp.Def Speed
Omastar: 70 60 125 115 70 55
Kabutops: 60 115 105 65 70 80
Omastar has high Sp.Atk equivalent to Kabutops' high Atk.
Kabutops has good Def, but Omastar's Def is way better.
Omastar's low Atk is like Kabutops' low Sp.Atk.
Besides the offense priority, the main difference between the two is that Omastar has better Def, while Kabutops is faster. Kabutops isn't necessarily good at KO-ing foes better than Omastar, since both specialize their stat with a 115. In a regular battle, Omastar is probably better than Kabutops with the higher Def. Kabutops does have higher Speed, but that stat isn't high enough to match the much faster Pokémon. Basically, the difference between their Def stats is more significant than the difference between their Speed stats.
In Pokedex order: Omanyte Omastar Kabuto Kabutops Aerodactyl Cranidos Rampardos Shelldon Bastiodon
In Red Blue Yellow they are Aerodactyl Omanyte Omastar Kabuto Kabutops In Sapphire Ruby Emerald they are Lileep Cradilly Anorith Armaldo
The only way to see or obtain a Kabutops is through trade in your instance. Perhaps someone will trade you a Kabuto or Kabutops if it's a Kabuto you will need to train it to level 40 for it to evolve to Kabutops.
Whether Kabuto is better than Omanyte depends on the context of their use in Pokémon battles or gameplay. Kabuto evolves into Kabutops, which has higher attack and speed stats, making it more effective in physical offense. On the other hand, Omanyte evolves into Omastar, known for its special attack and defensive capabilities. Ultimately, the choice between them hinges on your team composition and strategy.
In Pokémon Red, Pokémon Blue and Pokémon Yellow as well as Pokémon FireRed and Pokémon LeafGreen, Brock's Pokémon are Geodude and Onix. In Pokémon Gold, Silver and Pokémon Crystal as well as Pokémon HeartGold and Pokémon SoulSilver, his Pokémon are Graveler, Onix, Rhyhorn, Omastar and Kabutops. During Brock's rematches in Pokémon HeartGold and Pokémon SoulSilver while battling in Saffron City's Fighting Dojo, his Pokémon are Onix, Golem, Kabutops, Omastar, Relicanth and Rampardos. In Pokémon Black 2 and White 2, these Pokémon are in his party during the Kanto Leaders partof the tournament, the Pokémon care Golem, Kabutops, Onix, Omastar, Aerodactyl and Relicanth. During the Type Expert and World Leaders tournaments, his Pokémon are Kabutops, Onix, Golem, Aerodactyl, Rhyperior and Tyranitar.
The Dome Fossil is Kabuto/Kabutops and the Helix Fossil is Omanyte/Omastar
There is 1 Kabutops and 2 Omastar =]
In Pokedex order: Omanyte Omastar Kabuto Kabutops Aerodactyl Cranidos Rampardos Shelldon Bastiodon
You'd probably need to trade for Kabutops.
Graveler 51 Rhyhorn 51 Omastar 53 Onix 54 Kabutops 52
Personally I think kabutops is better.
In Red Blue Yellow they are Aerodactyl Omanyte Omastar Kabuto Kabutops In Sapphire Ruby Emerald they are Lileep Cradilly Anorith Armaldo
He has an Omastar, Kabutops, Golem (or Graveler, maybe both), Onix, and in the rematches, he has the above and the following: Rampardos and Relicanth
Lvl51 Graveler,Lvl 51 Rhyhorn,Lvl 53 Omastar, Lvl 54 Onix,Lvl 52 Kabutops
The only way to see or obtain a Kabutops is through trade in your instance. Perhaps someone will trade you a Kabuto or Kabutops if it's a Kabuto you will need to train it to level 40 for it to evolve to Kabutops.
Dome Fossil = Kabuto (Lv 40, evolves to Kabutops) Helix Fossil = Omanyte (Lv 40, evolves to Omastar) Old Amber = Aerodactyl
There are several fossils out there, but the weakest by far are kabutops, omastar, and armaldo. The best in my opinion is probably bastiodon because of his great defense, and rampardos for his huge attack skill.