Temporal range: Llandovery–Ludlow
|Restoration of Hughmilleria socialis|
Stratigraphy and ecology
Fossils of Hughmilleria have been found in Silurian deposits from the Llandovery and Ludlow epochs. Together with its close relatives, Hughmilleria dominated the communities in brackish and fresh water, while Pterygotus and Eurypterus dominated marine environments.
The family Hughmilleriidae, which lived from the Ordovician to Permian periods, were small to large forms with outer surfaces that were either smooth or that had transverse integuemental folds or semilunar to pointed scales. The telson (tail) was lanceolate or somewhat expanded. Hughmilleriidae also had chelicerae (claws in front of the mouth) that were small to medium-sized, without teeth. Their walking legs were stout, with spines, and their swimming paddles were narrow. The genital appendages of males were narrow, without lateral points.
Hughmilleria is distinguishable from other Hughmilleriidae by the postlateral prolongation of the first postabdominal segment. The telson is lanceolate in form. The chelicerae are medium-sized. The prosoma (head) is ovate, with compound eyes located near the edge of the front corners.
- Hughmilleria shawangunk Clarke, 1907
- Hughmilleria socialis Sarle, 1903
- Hughmilleria wangi Tetlie, Selden & Ren, 2007
- O. Erik Tetlie (2007). "Distribution and dispersal history of Eurypterida (Chelicerata)" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology 252: 557–574. doi:10.1016/j.palaeo.2007.05.011.
- Michael J. Benton & David A. T. Harper (2009). "Ecdysozoa: arthropods". Introduction to paleobiology and the fossil record. Wiley-Blackwell. pp. 361–388. ISBN 978-1-4051-4157-4.
- Størmer, L. 1955. Merostomata. Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata, P: 30.