Protis Ehlers, 1887

Genus Protis Ehlers, 1887 View in CoL

Type species. Protis simplex Ehlers, 1887 View in CoL

Generic diagnosis (from Rzhavsky et al., 2013 emended). Tube white, opaque, without peristomes, keel present in P. akvaplani View in CoL . Operculum absent or one or more membranous globular opercula present on normal pinnulate radiole(s). Arrangement of radioles pectinate, up to 20 per lobe. Inter-radiolar membrane absent. Radiolar eyes not observed. Stylodes absent. Mouth palps absent. Seven (six in P. akvaplani View in CoL ) thoracic chaetigers. Collar trilobed with entire edge, tonguelets absent. Thoracic membranes variable, ending at chaetiger 3 in P. akvaplani View in CoL and in P. melmackenzieae View in CoL n. sp. or long, at least to end of thorax and usually forming ventral apron across anterior abdominal segments. Collar chaetae fin-and-blade and limbate. Apomatus View in CoL chaetae present. Thoracic uncini saw-shaped with about 6 (up to 12 in P. melmackenzieae View in CoL n. sp.) teeth, anterior fang simple pointed. Triangular depression absent. Abdominal chaetae flat narrow geniculate with rounded teeth, slightly more triangular blade in P. hydrothermica View in CoL . Abdominal uncini rasp-shaped in all segments or saw-shaped in anterior segments, with up to 6 teeth in profile, approximately 5–7 teeth in a row above fang. Achaetous anterior abdominal zone absent. Long posterior capillary chaetae present. A posterior glandular pad may be present. Remarks. Ehlers’ original diagnosis does not mention an operculum at all, the lack of an operculum thus was considered a characteristic feature of Protis View in CoL . Kupriyanova and Jirkov (1997) extended the diagnosis to include individuals with one or more opercula, following the description of the abyssal P. polyoperculata View in CoL by Kupriyanova (1993a). Rzhavsky et al. (2013) emended the diagnosis to include their newly described P. akvaplani View in CoL , having tubes with a very distinct high keel and six thoracic segments. Here we further emended the diagnosis to reflect the short thoracic membranes in P. akvaplani View in CoL and P. melmackenzieae View in CoL n. sp.