石鱉是軟體動物門多板綱(學名:Polyplacophora)物種的通稱,又名石鱉綱(Loricata[1]),約有900多個物種[2]。其特徵為內圈一般都有八片緊鄰排列之硬殼,外圈則是肌肉組織。
石鱉為海生軟體動物,大部分物種生活在潮間帶和潮下帶淺水區的岩石上,常可在退潮後的潮間帶岩石上見到,但也有一些物種生活在較深海域[3]。可以食用。
現時本綱物種的分類基本上依從Sirenko (2006)的分類,大致如下[4]:
- 多板綱 Polyplacophora de Blainville, 1816
- 古石鱉亞綱 Paleoloricata Bergenhayn, 1955
- Order Chelodida Bergenhayn, 1943
- Order Septemchitonida Bergenhayn, 1955
- 新石鱉亞綱 Neoloricata Bergenhayn, 1955
- 石鱉目 Chitonida Thiele, 1909:包括多板綱中絕大多數的種類,例如:花斑銼石鱉。
- 毛膚石鱉亞目 Acanthochitonina
- Superfamily Cryptoplacoidea H. Adams & A. Adams, 1858
- 毛膚石鱉科 Acanthochitonidae Pilsbry, 1893
- Family Cryptoplacidae H. Adams & A. Adams, 1858
- Family Hemiarthridae Sirenko, 1997
- Family Makarenkoplacidae Sirenko & Dell'Angelo, 2015 †
- Superfamily Mopalioidea Dall, 1889
- 石鱉亞目 Chitonina
- Superfamily Chitonoidea Rafinesque, 1815
- Family Callistoplacidae Pilsbry, 1893
- Family Callochitonidae Plate, 1901
- Family Chaetopleuridae Plate, 1899
- 石鱉科 Chitonidae Rafinesque, 1815
- 薄石鱉科 Ischnochitonidae Dall, 1889
- Family Loricidae Iredale & Hull, 1923
- Family Spinochitonidae Dell'Angelo, Lesport, Cluzaud & Sosso, 2018 †
- Superfamily Schizochitonoidea Dall, 1889
- Schizochitonidae Dall, 1889
- 鱗側石鱉目 Lepidopleurida Thiele, 1909:例如鱗側石鱉(Lepidopleurus)。
- 毛膚石鱉亞目 Lepidopleurina Thiele, 1909:體呈長形或橢圓形,大小不一。例如:紅條毛膚石鱉
- Family Abyssochitonidae Dell'Angelo & Palazzi, 1989
- 漢利石鱉科 Hanleyidae Bergenhayn, 1955
- 鱗側石鱉科 Leptochitonidae Dall, 1889
- Family Nierstraszellidae Sirenko, 1992
- Family [[Protochitonidae Ashby, 1925}} †
- 目地位未定(Incertae sedis)
- Family Scanochitonidae Bergenhayn, 1955
- Family Olingechitonidae Starobogatov et Sirenko, 1977
- Family Haeggochitonidae Sirenko et Starobogatov, 1977
- Family Ivoechitonidae Sirenko et Starobogatov, 1977