thumb|left|As members of [[Myriapoda, centipedes like this Scolopendra polymorpha are part of subphylum Uniramia]]

Uniramia (uni – one, ramus – branch, i.e. single-branches) is formerly recognised group within Arthropoda, now recognised as non-monophyletic, united by their strictly uniramous (single branched) appendages.

The name Uniramia was temporarily rejected as a polyphyletic group, but was later redefined to only include Myriapoda and Hexapoda. This subphylum Uniramia was considered to be characterized by their uniramous (single-branching) appendages, one pair of antennae and two pairs of mouthparts (single pairs of mandibles and maxillae). Their body forms and ecologies are diverse. While most unirames are terrestrial, "some are aquatic for part or all of their life cycles. be an infraphylum beneath Mandibulata, or may no longer be a valid category after closer, cladistics-based genetic study.

The Crustacea were generally considered the closest relatives of the Uniramia, and sometimes these were united as Mandibulata. However, the competing hypothesis — that Crustacea and Hexapoda form a monophyletic group, the Pancrustacea, to which the Myriapoda are the closest relatives — has support from molecular and fossil evidence.

Notes

References

  • Paleos Metazoa: Arthropoda: Uniramia
  • Bio 105–106 demo
  • A Cladistic Analysis of Arthropoda: Examining the Evolution of Biramous Appendages and Mandibles, Katherine McBride, Lindsey Moll, Whitney Zurat, Susquehanna University
  • Uniramia at palaeos