Dekatriata Explained

Dekatriata is a clade of planatergan chelicerates including the groups Arachnida, Chasmataspidida, Eurypterida^[1] and additionally two stem-genera Winneshiekia and Houia.^[2] Dekatriata is defined by an opisthosoma with 13 segments as groundplan (the number proposed to be secondarily reduced in most arachnid orders) and fused, plate-like appendages on the first opisthosomal segment (somite VII).

Notes and References

1. Lamsdell. James C.. 2012-12-18. Revised systematics of Palaeozoic 'horseshoe crabs' and the myth of monophyletic Xiphosura. Zoological Journal of the Linnean Society. en. 167. 1. 1–27. 10.1111/j.1096-3642.2012.00874.x. 0024-4082. free.
2. A new Ordovician arthropod from the Winneshiek Lagerstätte of Iowa (USA) reveals the ground plan of eurypterids and chasmataspidids. James. Lamsdell. Derek E. G.. Briggs. Huaibao P.. Liu. Robert M.. McKay. The Science of Nature. 102. 9–10. 63. 2015. 10.1007/s00114-015-1312-5. 26391849. 2015SciNa.102...63L. 8153035.