• DOI:10.3853/J.0067-1975.41.1989.139
• Corpus ID: 84292243

The scopelocheirid genus Aroui (Crustacea: Amphipoda: Lysianassoidea) with notes on the association between scopelocheirid amphipods, cassid gastropods and spatangoid echinoids

@article{Lowry1989TheSG,
  title={The scopelocheirid genus Aroui (Crustacea: Amphipoda: Lysianassoidea) with notes on the association between scopelocheirid amphipods, cassid gastropods and spatangoid echinoids},
  author={James K. Lowry and Helen Stoddart},
  journal={Records of The Australian Museum},
  year={1989},
  volume={41},
  pages={111-120}
}

• J. Lowry, H. Stoddart
• Published 22 September 1989
• Biology
• Records of The Australian Museum

Formerly Aroui was a monotypic scopelocheirid genus known only from the Mediterranean Sea. The type species, Aroui setosus Chevreux, is redescribed. It is shown that a neotype, recently established for this species, is invalid, and a lectotype is selected from syntype material in the Museum National d'Histoire Naturelle, Paris. A second species, Aroui hamatopodus, is described, based on widespread collections from the Australian continental shelf and slope. The genus is rediagnosed and distinguished from all other scopelocheirids by two autapomorphic character states. Evidence is presented which suggests that scopelocheirids are very primitive scavengers, and that there is a three-way association between cassid gastropod predators, scopelocheirid amphipod scavengers and their common prey, spatangoid echinoids. An hypothesis is presented which suggests that scopelocheirid scavengers may have evolved by the early Tertiary and that the association involving cassid gastropods and spatangoid echinoids may date from this time. LOWRY, I.K. & H.E. STODDART, 1989. The scope1ocheirid genus Aroui (Crustacea: Amphipoda: Lysianassoidea) with notes on the association between scope1ocheirid amphipods, cassid gastropods and spatangoid echinoids. Records of the Australian Museum 41 (2): 111-120. 111 Aroui setosus Chevreux, 1911 is well known from the works of Chevreux (1911) and Stroobants (1976). It is the type species of the genus Aroui Chevreux which until now was known only from the Mediterranean Sea. Although Aroui has been recognised by Stroobants (1976) and Bellan-Santini (1985) as closely related to Scopelocheirus Bate, the exact relationship has not been fully understood until now because Aroui has been monotypic. Among the extensive collections of lysianassoid amphipods from Australian waters we have found only one species of scopelocheirid lysianassoid, a new species of Aroui, which is described below. This has allowed us to rediagnose Aroui and consider its relationship to Scopelocheirus and other scopelocheirid genera. Stroobants apparently believed that A. setosus was represented by a holotype because she reported being unable to find "la type" in either the Museum National d'Histoire Naturelle, Paris, (MNHN) or the Musee 112 Records of the Australian Museum Vol. 41 Oceanographique, Monaco (MOM). She subsequently established a neotype for A. setosus from new material collected by E. Dupont in southern Sardinia (Stroobants, 1976:239). However, we believe that all specimens of A. setosus from Chevreux' s original collection should be regarded as syntypic material, as has always been done by the institutions which hold this material. The designation of a neotype of A. setosus by Stroobants is invalid for two reasons. It is contrary to article 75(b)(ii) of the Code of the International Commission on Zoological Nomenclature. Aroui is a monotypic genus. Although the species had not been recollected until Stroobants obtained new material from Sardinia, there had been no question concerning its identity. It is easily distinguished from Scopelocheirus hopei, its closest relative, and Stroobants apparently had no difficulty identifying A. setosus and S. hopei in her collections. Thus there were no "exceptional circumstances" or complex zoological problem to justify the establishment of a neotype. It is contrary to article 75(d)(iii). Stroobants failed to provide reasons for believing the types of A. setosus to be lost; syntypes were present at the time in three major institutions, those in the British Museum (Natural History), London and the Musee Oceanographique having been reported in the recent literature (Belloc, 1960; Thurston & AlIen, 1969). In 1984 we examined the syntype material of A. setosus in the Museum National d'Histoire Naturelle. These specimens are in good condition. We have designated a lectotype, which is registered as Am 3995, from the MNHN Am 900 collection. This specimen is redescribed and illustrated below to allow comparison with the new species. The remaining syntypes (93 in the Museum National d 'Histoire N aturelle, Am 900 and 90 I, 3 in the Musee Oceanographique, 3 in the British Museum (Natural History), 1912:4:4:5-7 and 2 in the Australian Museum, Sydney, P35541) become paralectotypes. In accordance with Article 75(h) of the ICZN we referred this matterto the Commission for a ruling and received a reply (P.K. Tubbs, in litt.) confirming our interpretation. Specimens of the new species are deposited in the Australian Museum, Sydney (AM) and the Western Australian Museum, Perth (W AM).