爬行亞目

在較舊的分類，爬行亞目連同游泳亞目是十足目兩個亞目：當中爬行亞目包括了在水裡爬行的物種；而游泳亞目包括了各種的蝦。1963年，Martin Burkenroad發現游泳亞目是並系群，而且不符合命名法則，所以把十足目重新分類為枝鰓亞目（Dendrobranchiata）及抱卵亞目（Pleocyemata）兩個亞目：抱卵亞目包含了舊有爬行亞目的所有成員，即蟹、龍蝦、螯蝦及其他，再加上真蝦下目（Caridea）及Stenopodidea[1]。儘管爬行亞目依然是個有效的单系群，但不再是亞目級，被視為不分類支序[2]。

The name Reptantia means "those that walk", and contains those 十足目s whose primary mode of locomotion is to walk along a surface using the pereiopods rather than swimming through the water with the pleopods. Despite this, many reptants are able to propel themselves through the water, and many non-reptants can and will walk.

The 支序图 below shows Reptantia under the sub-order 抱卵亞目 within the larger order 十足目, from analysis by Wolfe et al., 2019.[2]

爬行亞目包括下列下目：

• 無螯下目 Achelata (spiny, slipper, and furry lobsters)
• Polychelida (benthic crustaceans)
• 雕蝦下目 Glypheidea(glypheoid lobsters)
• 螯蝦下目 Astacidea(true lobsters, reef lobsters, and crayfish)
• Axiidea (mud lobsters and ghost shrimp)
• Gebiidea (mud lobsters and mud shrimp)
• 異尾下目 Anomura：寄居蟹、鎧甲蝦及其他
• 短尾下目 Brachyura：螃蟹