Artistic reconstructions of Fortiforceps foliosa and Sklerolibyon maomima gen

''Fortiforceps'' is an extinct genus of

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

megacheiran marine arthropod known from the

Chengjiang biota The Maotianshan Shales () are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation or Heilinpu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized orga ...

of Yunnan, China. It was originally described by Hou and Bergström in 1997, and redescribed in 2020. It was relatively small, at or less in length. The head had a pair of large, stalked eyes, a pair of frontal projections, as well as a pair of great appendages, like other megacheirans, along with two other

cephalic A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may no ...

appendages. The trunk had either 20 or 22 segments, depending on the specimen. These segments had pronounced blade-like spines on their upper-outer edge. Each of the trunk segments (aside from the last, typically 20th segment) were associated with pairs of

biramous The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, ...

limbs, which probably have seven podomeres and like other megacheirans, have paddle-shaped exopods. The trunk terminated with a forked tailpiece, which on their outer edges had rod-like structures. The two lobes were separated by a rectangular central piece. It has been placed as a member of the family Jiangfengiidae, alongside ''

Jianfengia ''Jianfengia'' is an extinct genus of Middle Cambrian (Atdabanian) megacheiran arthropod found in the Maotianshan Shale Lagerstätte of China. It contains the single species ''Jianfengia multisegmentalis''.Sklerolibyon ''Sklerolibyon'' is an extinct genus of megacheiran marine arthropod, known from the Cambrian aged Chengjiang biota of Yunnan, China. It is a member of the family Jianfengiidae, alongside '' Jianfengia'' and '' Fortiforceps,'' and possibly also ...

'' and possibly ''

Parapeytoia ''Parapeytoia'' is a genus of Cambrian arthropod. The type and only described species is ''Parapeytoia yunnanensis'', which lived over 518 million years ago (Cambrian Stage 3) in the Maotianshan shales of Yunnan, China. Unidentified fossils from ...

''.

References

{{Taxonbar, from=Q21368634 Megacheira Cambrian arthropods Cambrian animals of Asia Cambrian Series 2 first appearances Maotianshan shales fossils Fossil taxa described in 1997 Prehistoric arthropod genera