Armorloricus, a new genus of Loricifera (Nanaloricidae) from Trezen ar Skoden (Roscoff, France)

TitleArmorloricus, a new genus of Loricifera (Nanaloricidae) from Trezen ar Skoden (Roscoff, France)
Publication TypeJournal Article
Year of Publication2004
AuthorsKristensan, R. M., & Gad G.
Refereed DesignationUnknown
JournalCahiers de Biologie Marine
Volume45
Issue2
Pagination121-156
ISSN0007-9723
Abstract

Two new species of Loricifera (Nanaloricidae), Armorloricus elegans sp. nov. and A. davidi sp. nov. are described as representatives of a new genus from the sediment of Trezen ar Skoden (Roscoff, France) in the vicinity of the type locality of Nanaloricus mysticus. Diagnosis and description are based on all life history instars: adults, postlarvae, and Higgins-larvae, all collected from the upper surface layer of shell gravel at 50-55 m depth. The adults of the new genus are characterized by a smooth lorica with large midventral and laterodorsal plates. The dorsal plate of the lorica is longitudinally subdivided into three additional plates. The short mouth cone has an extremely long mouth tube. The clavoscalids and lateroventral trichoscalids display sexual dimorphism in both species. In the males the clavoscalids possess next to the main branch two additional club-shaped branches. The leglike scalids of the second row are smooth, strongly sclerotized, and distally as broad as the clavoscalids. Internally, the prepharyngeal armature of adults is equipped with an additional posterior part called the manubrium, which consists of three fused bracelets. The respective stout Higgins-larvae display an angular lorica and toes winged by two short mucrones ending distally in spared tips. Both the toes and the lorica have a honeycomb sculpture. Additional larval features are short, solid scalids covering the introvert and short locomotory appendages inserting ventrally on the trunk. The distinguishing characters of Armorloricus gen. nov. and Nanaloricus are discussed in detail. Apart from Nanaloricus, this is the first report of an additional taxon of the Nanaloricidae, which results in a revision of the characters at the family level. Investigations of the type material indicate a highly modified status of the Nanaloricidae, which can be shown e.g. in the transformation and arrangement of scalids in the adults and even in the Higgins-larvae. Therefore new scalid distribution schemes of all life instars are included.