page_title: Parahughmilleria
section_title: Creation of the genus and additional species
hierarchical_section_title: Parahughmilleria / History of research / Creation of the genus and additional species
caption_attribution_description: English: Restoration of fossils used for the original description of the eurypterid species Parahughmilleria salteri. a, carapace. b, holotype, nearly complete operculum with female genital appendage. c, paratype. Metasomal tergites and telson. d, metastoma. e, paratype. Specimen with carapace, complete mesosoma and anterior tergites of the metasoma. Based on Kjellesvig-Waering, 1961.
context_page_description: Parahughmilleria is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Parahughmilleria have been discovered in deposits of the Devonian and Silurian age in the United States, Canada, Russia, Germany, Luxembourg and Great Britain, and have been referred to several different species. The first fossils of Parahughmilleria, discovered in the Shawangunk Mountains in 1907, were initially assigned to Eurypterus. It would not be until 54 years later when Parahughmilleria would be described.
  Parahughmilleria is classified in the family Adelophthalmidae, the only clade in the superfamily Adelophthalmoidea. This clade was characterised by their small size, their parabolic carapaces and the presence of epimera on the seventh segment, among others. Like its relatives, Parahughmilleria possessed reniform eyes and spines on its appendages. The largest species was P. major at 12.5 cm, making it a small-sized eurypterid, although it has been suggested that it and P. hefteri may represent the same species.
context_section_description: In 1961, Kjellesvig-Waering erected the genus Parahughmilleria (meaning "near Hughmilleria") and assigned P. salteri as the type species. He noticed that Parahughmilleria differed from Hughmilleria in the development of supplementary lobes on the operculum (as in Adelophthalmus) and in the position of the intramarginal eyes, unlike the marginal eyes of Hughmilleria. P. salteri was described based on a holotype and four paratypes. In this species, the prosoma was widely rounded, smooth, nearly semicircular and highly arched, and was surrounded by a narrow and marginal rim. The base formed a straight line. The eyes were small, reniform and placed intramarginally. The ocelli were small and placed almost centrally on the prosoma. The telson was flat, lanceolate and broad at the anterior. An operculum that shows the lobes has been described as the holotype. It comprises two opercular flaps (protruding extensions lateral to the genital appendage) rounded at the corners and separated. They were separated from each other at the midsection and above the median appendage. The specific name of this species honors John William Salter, an English naturalist and paleontologist, and its maximum size was of 8 cm (3.1 in). Kjellesvig-Waering also assigned P. phelpsae to the genus, but this species has since been raised to the genus level under the name Pittsfordipterus.
  Later, in 1973, Leif Størmer described two new species, P. major and P. hefteri. Both represent the largest and the smallest species, respectively. P. hefteri is a well-known species that has been found both in Europe and in North America. It had enlarged spines on at least one podomere (leg segment) and a relatively wide swimming leg. Both species had a sharply truncated posterior margin in the metastoma, which only differ by their ratios. P. major had a longer telson with more lateral concave
  margins and a broader base, a more slender body and narrower paddles than P. hefteri. Størmer also noticed slight differences in the genital appendage. All these differences can be explained by ontogenetic stages, that is, different developmental stages of the animal throughout its life.
  In 2012, the Russian paleontologist Evgeniy S. Shpinev described another species, P. longa, from the Khakassia, Russia. Its specific name, from the Latin longus, refers to the unusual length of its prosoma compared to the other species of the genus, about 17 mm (about 0.67 in) long and 18 mm (0.71 in) wide. The holotype and only known specimen (PIN1220/3) consists of an incomplete prosoma and fragments from a swimming leg. In this species, the prosoma was surrounded by a narrow marginal margin. The posterior margin was slightly convex. The eyes were small and, as in other species, reniform. The swimming leg was of Adelophthalmus-type, with the fifth, sixth, seventh and part of the eighth segment known. The seventh segment was very long and narrow, while the eight segment was irregular along the outer edge. This species is distinguished by having a prosoma narrower and longer than others.
  In addition, Markus Poschmann transferred Erieopterus statzi to Parahughmilleria in 2015 based on the proportions of paddle segments which were more related to those of P. hefteri. This species is only known by a single specimen that was originally assigned to Eurypterus, but Kjellesvig-Waering classified it to Erieopterus based on the shape of the prosoma lacking of ornamentation and on the highly serrated paddle. Nine years before Poschmann referred E. statzi to Parahughmilleria, he and O. Erik Tetlie had already suggested this change, which was not done because of the need to study the material.
caption: Fossils of P. salteri. (a) a carapace, (b) the holotype, nearly complete operculum, (c), metasomal tergites and telson, (d) metastoma and (e) a specimen with complete mesosoma and part of the walking legs.
exif: {}