After Hou & Bergström, 1997, Chen, Waloszek & Maas, 2004, and Edgecombe, García-Bellido & Paterson, 2011
<==o †Megacheira Hou & Bergström, 1997 |?- †Kiisortoqia soperi Stein, 2010 |--o †Kootenichelidae Legg, 2013 | |-- †Worthenella cambria Walcott 1911; M.Camb. WNAm. | |?- †Pseudoiulia cambriensis Hou & Bergström, 1998; M.Camb. EAs. | `-- †Kootenichela deppi Legg, 2013; M.Camb. WNAm. |--o †Fortiforcipida Hou & Bergström, 1997 | `--o †Fortiforcipidae Hou & Bergström, 1997 | `-- †Fortiforceps foliosa Hou & Bergström, 1997 `--+--o †Yohoniida Simonetta & Delle Cave, 1975 | `--o †Yohoiidae Henriksen, 1928 | |-- †Jianfengia multisegmentalis Hou, 1987 | `-- †Yohoia tenuis Walcott, 1912 `--+-- †Haikoucaris ercaiensis Chen, Waloszek & Maas, 2004 `--o †Leanchoiliida Størmer, 1944 |--o †Enaliktidae Siveter, Briggs, Siveter, Sutton, Legg & Joomun, 2014 | |-- †Bundenbachiellus giganteus Broili, 1930 [Eschenbachiellus wuttkensis] | `-- †Enalikter aphson Siveter, Briggs, Siveter, Sutton, Legg & Joomun, 2014; Sil. WEu. `--o †Leanchoiliidae Raymond, 1935 [incl. Alalcomenaeidae Simonetta & Delle Cave, 1975; Actaeidae Simonetta & Delle Cave, 1975] |?- †Actaeus armatus Simonetta, 1977 |-- †Dicranocaris guntherorum Briggs et al., 2008 |--o †Alalcomeneus Simonetta, 1970 [Alalcomenaeidae Simonetta & Delle Cave, 1975] | |-- †A. cambricus Simonetta, 1970 | `-- †A. elegans (Luo & Hu in Luo et al., 1999) `--+-- †Oestokerkus megacholix Edgecombe, García-Bellido & Paterson, 2011 `--o †Leanchoilia Walcott, 1912 |-- †L.? hanceyi Briggs & Robison, 1984 |-- †L. persephone Simonetta, 1970 |?- †L. protogonia Simonetta, 1970 `--+-- †L. superlata Walcott, 1912 `-- †L. illecebrosa (Hou, 1987) [Alalcomeneus? illecebrosus Hou, 1987; Alalcomeneus illecebrosus Hou; Chen et al., 2004]
Note:
Phylogenetic treatment of Chen et al. (2004) differs greatly from that of Hou & Bergström (1997). In last revision of this page I decided to include †Haikoucaris Chen et al., 2004 to the Megacheira Hou & Bergström, 1997, because they are the only taxa treated by Chen et al. when discussing the relationships of †Haikoucaris. The phylogeny of Chen et al. differs in placing †Haikoucaris closer to Chelicerata sensu stricto. Chen et al. also place megacheirans as paraphyletic basal polytomy of their Chelicerata sensu lato.
While describing a new Leanchoiliid species, Oestokerkus megacholix, Edgecombe et al. (2011) reanalysed relationhips of Megacheira. In their analysis Haikoucaris is indeed a Megacheiran. They also reinstated megacheirans as a potential sistergroup of Chelicerata.
Legg (2013) and Siveter et al. (2014) consider megacheirans as paraphyletic grade of basal arthropods, close to Euarthropoda.
Reference(s):
- Chen, J.-Y., Waloszek, D. & Maas, A., 2004: a new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicera and raptorial antero-ventral appendages.
–Lethaia: Vol. 37, #1, pp. 3-20 - Conway Morris, S., 1993: The fossil record and early evolution of the Metazoa.
–Nature, vol. 361, 21 January, pp. 219-225 - Edgecombe, G. D., García-Bellido, D. C. & Paterson, J. R., 2011: A new leanchoiliid megacheiran arthropod from the lower Cambrian Emu Bay Shale, South Australia.
–Acta Palaeontologica Polonica: Vol. 56, #2, pp. 385-400 [doi: 10.4202/app.2010.0080] - Hou X. & Bergström, J., 1997: Arthropods of the Lower Cambrian Chengjiang fauna, southwest China.
–Fossils & Strata, Number 45, 22nd December 1997, pp. 1-116 - Legg, D., 2013: Multi-Segmented Arthropods from the Middle Cambrian of British Columbia (Canada).
–Journal of Paleontology: Vol. 87, #3, pp. 493-501 [doi: 10.1666/12-112.1] - Siveter, D. J., Briggs, D. E. G., Siveter, D. J., Sutton, M. D., Legg, D. & Joomun, S., 2014: A Silurian short-great-appendage arthropod.
–Proceedings of the Royal Society B: Biological Sciences: Vol. 281, #1778, pp. [doi: 10.1098/rspb.2013.2986] - Stein, M., 2010: A new arthropod from the Early Cambrian of North Greenland, with a ‘great appendage’-like antennula.
–Zoological Journal of the Linnean Society: Vol. 158, #3, pp. 477-500 [doi: 10.1111/j.1096-3642.2009.00562.x]