Notopais Hodgson 1910
- Dataset
- Review of the deepwater asellote genus Notopais Hodgson, 1910 (Crustacea: Isopoda: Munnopsididae) with description of three new species from the southwestern Pacific
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Malacostraca
- order
- Isopoda
- family
- Munnopsidae
- genus
- Notopais
description
5. Pereonites 6 – 7 dorsal surface with no spines; cephalon with no spines on anterolateral margins ......................................................................................................................... 6 — Pereonites 6 – 7 dorsal surface both with pair of small spines; cephalon anterolateral margins each with single small spine, another pair of spines are set well back from margin but are not on central dome; pereonite 5 anterior margin with 4 small spines .. ........................................................................................................................ N. spinosa 6. Cephalon with 4 spines, which are small enough to be regarded as tubercles; pereonites 2 – 3 anterior margin with 6 spines; pereonite 5 anterior margin smooth; antenna 2 article 1 only article with distolateral angle with defined spine and terminal robust seta ................................................................................................................. N. minya n. sp. — Cephalon with 4 large, distinct spines, the inner pair larger than outer pair; pereonites 1 – 4 anterior margins with continuous row of spines (when mature adult); pereonite 5 dorsalsurfacewithpairofroundeddomes, oneeachsideofcentre, anteriormarginsmooth N. magnifica
description
Description: Body compact, cuticle brittle; cephalon trapezoid, broad, wider posteriorly, dorsal face domed, ventrally, cephalon flattened, frons narrow allowing maxillipeds to appear almost horizontal in lateral view. Pereonites 2 – 4 anterolateral margins usually with spines, anterior margins usually with spines, if not, margins with robust setae; all spines tipped with robust (pedestal) setae, making spines look more pronounced. Antenna 2 articles 1 – 4 short, combined length less than half of length of article 5; article 1 distolateral angle with prominent spine, hornlike, and terminal robust seta; article 6 more elongate than 5. Mandible massive, calcareous; palp absent; incisor process large, rounded, without defined cusps; lacinia mobilis reduced or absent. Pereopods 5 and 6 carpus expanded, discoidal, flat; propodus flat, expanded; superior margin of ischium and both margins of carpus and propodus with row of evenlyspaced long plumose setae. Pereopod 7 ambulatory, but more robust and retaining long, plumose setae similar to that of pereopods 5 and 6. Pleon triangular in dorsal view, with domed medial keel. Operculum vaulted, with prominent medial keel. Uropods biramous, small, flat.
diagnosis
Diagnosis: Cephalon frons narrow, allowing for almost horizontal position of maxillipeds in situ in lateral view. Pereonites 1 – 4 anterior margins usually with spines, if not, margins with robust setae; all spines tipped with robust (pedestal) setae, making spines look more pronounced. Antenna 2 article 1 distolateral angle with hornlike prominent spine and terminal robust seta. Mandible palp absent; incisor process large, rounded, without defined cusps; lacinia mobilis reduced or absent. Pereopods 5 and 6 carpus and propodus flat, expanded, margins with plumose setae. Pereopods 7 ambulatory, robust, retains plumose setae similar to pereopods 5 and 6. Uropods biramous.
discussion
Remarks: Notopais can be distinguished by: the flattened appearance of its mouthparts in situ, pereonites 1 – 4 anterior margins most commonly with spines or otherwise with robust setae; all spines tipped with robust (pedestal) setae; antenna 2 article 1 with produced anterolateral angle with a distal robust seta; pereopods 5, 6 and 7 with superior margin of ischium and both margins of the carpus and propodus with row of evenly spaced long, plumose setae; and uropods biramous, small and flat. On studying Sars’ material of Echinozone coronata (Sars, 1870) the type species for Echinozone genus, it can be found that Notopais differs from this genus in cephalon and body shape, the presence of pedestal setae and with the distinct shape of antenna 2 article 1. In Notopais the frons is narrower compared with Echinozone, allowing the frontal arch to meet up with the maxillipeds at a wider angle, giving them a more horizontal appearance. The more acute angle between the frontal arch and maxillipeds seen in Echinozone gives it a much more triangular appearance, especially in lateral view. This structure adds more emphasis on the curvature of the animal and its body is more arched than in Notopais. Notopais has pedestal setae tipping all of its spines, similar to that found in Bathybadistes and these are not present in Echinozone. Although many Ilyarachninae (including Echinozone) have a robust seta and / or a spine on the anterolateral angle of antenna 2 article 1, the shape of this in Notopais is distinct and exclusive to this genus. Its shape is akin to a bull’s horn and is always tipped with a robust seta making it more pronounced. This genus now contains: Notopais beddardi n. sp., N. zealandica n. sp., N. minya n. sp., N. magnifica (Vanhöffen, 1914) comb. nov., N. quadrispinosa (Beddard, 1886) comb. nov., N. spicata Hodgson, 1910 (type species) and N. spinosa (Hodgson, 1902) comb. nov. The genus appears to be restricted to the Southern Hemisphere, from Antarctic waters to the southeast continental slope of Australia, at depths from 36 to 1640 metres. Key to the species of Notopais
materials_examined
Type species Notopais spicatus Hodgson, 1910, by monotypy.
Name
- Homonyms
- Notopais Hodgson 1910
- Notopais