Fossil of Kottixerxes gloriosus, copyright RCFossils.

Belongs within: Pancrustacea.

The Euthycarcinoidea are a group of primarily aquatic arthropods known from freshwater or brackish water environments in the Late Ordovician or Early Silurian to the Middle Triassic (Vaccari et al. 2004).

Characters (from Vaccari et al. 2004): Sphaeroidal processes present at lateral edge of articulation between short anterior cephalic tergite and longer posterior cephalic tergite; mandibles present beneath posterior cephalic tergite, with mandible apparently lacking a palp; trunk divided into pedigerous pre-abdomen and narrow, limbless post-abdomen; multiple wide sternites associated with each pre-abdominal tergite, ratio of sternites per tergite increasing posteriorly with decoupling of tergal and sternal segmentation; antenniform pre-abdominal limbs with short segment; slender curved apodeme originating near each limb base.

<==Euthycarcinoidea [Archicopepoda, Euthycarcinata] VEE04
    |--Sottixeriformes B95
    |    |--Pieckoxerxes piekoae (Schram & Rolfe 1982) WA01
    |    `--Sottyxerxes multiplex Schram & Rolfe 1982 WA01
    `--Euthycarciniformes VEE04
         |--+--Apankura Vaccari, Edgecombe & Escudero 2004 VEE04
         |  |    `--*A. machu Vaccari, Edgecombe & Escudero 2004 VEE04
         |  `--Kalbarria brimmellae LSE13, WA01
         `--Kottixerxidae WA01
              |--+--Kottixerxes Schram 1971 WA01
              |  |    |--*K. gloriosus Schram 1971 WA01
              |  |    `--K. anglicus Wilson & Almond 2001 WA01
              |  `--+--Heterocrania rhyniensis LSE13, VEE04
              |     `--+--Arthrogyrinus Wilson & Almond 2001 LSE13, WA01
              |        |    `--*A. platyurus Wilson & Almond 2001 WA01
              |        `--+--Synaustrus brookvalensis (Riek 1964) LSE13, WA01
              |           `--Euthycarcinus [Euthycarcinidae] LSE13
              |                |--E. ibbenburensis VEE04
              |                `--E. kessleri Handlirsch 1914 WA01
              `--+--Smithixerxes Schram & Rolfe 1982 WA01
                 |    |--*S. juliarum Schram & Rolfe 1982 WA01
                 |    `--S. pustulosus Wilson & Almond 2001 WA01
                 `--Schramixerxes gerem (Schram & Rolfe 1982) LSE13, WA01

*Type species of generic name indicated


[B95] Bousfield, E. L. 1995. A contribution to the natural classification of Lower and Middle Cambrian arthropods: Food-gathering and feeding mechanisms. Amphipacifica 2: 3–34.

[LSE13] Legg, D. A., M. D. Sutton & G. D. Edgecombe. 2013. Arthropod fossil data increase congruence of morphological and molecular phylogenies. Nature Communications 4 (2485): 1–7.

[VEE04] Vaccari, N. E., G. D. Edgecombe & C. Escudero. 2004. Cambrian origins and affinities of an enigmatic fossil group of arthropods. Nature 430: 554–557.

[WA01] Wilson, H. M., & J. E. Almond. 2001. New euthycarcinoids and an enigmatic arthropod from the British coal measures. Palaeontology 44 (1): 143–156.

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