Pseudomma G.O. Sars, 1870

Wittmann, Karl J. & Chevaldonne, Pierre, 2021, First report of the order Mysida (Crustacea) in Antarctic marine ice caves, with description of a new species of Pseudomma and investigations on the taxonomy, morphology and life habits of Mysidetes species, ZooKeys 1079, pp. 145-227 : 145

Genus Pseudomma G.O. Sars, 1870

Pseudomma G.O. Sars, 1870a: 154-155 (new genus, description of type species); G.O. Sars 1870b: 48-53, Fig.-Tab. 4 (description, diagnosis); Czerniavsky 1887: 12 (key to species); Stephensen 1910: 128-133 (diagnosis, in key to genera); Tattersall and Tattersall 1951: 230-232 (diagnosis, description); Murano 1974: 288-331 (revision, key to species); Meland and Brattegard 1995: 108-143 (revision, key to North Atlantic species); Meland 2004: 1-19, Figs 1 - 4 (species diversity, phylogeny); Meland and Willassen 2004: 544, Fig. 4 (phylogeny, biogeography); Petryashov 2006: 1411, 1419 (Antarctic records; in key to species); Meland and Brattegard 2007: 44, Figs 3 - 8 (taxonomy; key to species); San Vicente 2011a: 48, Tab. 4 (list, diagnosis and key to Antarctic species); Petryashov 2014: 149 (Antarctic biogeography); Wittmann et al. 2014: 337 (taxonomy, species numbers); San Vicente 2017: Tabs. 1, 2 (geographical and bathymetric distribution); Mees and Meland 2021: AphiaID 119900 (taxon accepted).

Diagnosis.

Pseudommini with eyes reduced to single eyeplate without visual elements. Eyeplate with incomplete disto-median fissure. Appendix masculina large, setose. Lateral margin of antennal scale with smooth basal portion ending in a tooth. Carapace normal, with rounded anterior margin, dorsally covering at least five thoracic somites. Labrum, as far as known, with rounded rostral margin. Thoracic endopods essentially normal, non-prehensile, endopods 3-8 long and slender. Two or three pairs of oostegites contribute to marsupium wall, the two posterior pairs, as far as known, with setae on inner, as well as outer faces. Penes, as far as known, long and slender. Male pleopods with distinct sympod bearing separate, setose endopod and exopod. Female pleopods fused to small, setose, undivided plates with residual differentiation of the endopod as a pseudobranchial lobe. Endopod and exopod of uropods unsegmented, setose all around; endopod with or without spine. Telson mostly trapezoid, also linguiform or subtriangular, no cleft. Its lateral margins entirely smooth or proximally smooth with spines only along distal portions; terminal margin with spines, in several species also with medio-apical pair of setae.

Species inventory.

Type species is Pseudomma roseum G.O. Sars, 1870. World-wide, 46 species, including the new one, are here acknowledged, whereby P. oculospinum W.M. Tattersall, 1951 is included according to Wittmann et al. (2014). San Vicente (2011b) listed eleven species in his key to Antarctic and sub-Antarctic species. Twelve species, including the new one, are here acknowledged for waters of the Southern Ocean as in the following key:

Figures

Figure 1. Sampling stations (arrows) in ice caves of three islands near Dumont d'Urville Station (DDU), off Adelie Land, Antarctica.

Figure 3. Pseudomma kryotroglodytum sp. nov., holotype adult female BL 26.8 mm (A-E) and paratype subadult female 21.5 mm (F) A terminal portion of telson, dorsal, details show scales on left disto-mesial spine (B) and barbs on left terminal seta (C) D anterior half of cephalothorax, lateral, arrow points to distolateral edge of carapace E sixth pleomere with tail fan, lateral F example for pores (three to the left) and coat of scales on tergite of first pleomere.

Figure 4. Pseudomma kryotroglodytum sp. nov., holotype adult female BL 26.8 mm (A, B, E, F) and paratype subadult female 21.5 mm (C, D). A right antennula, dorsal B antenna with antennal gland, ventral, setae omitted from antennal scale C eyeplate and carapace expanded on slide, short arrow points to distolateral edge of carapace, detail (D) pore group in pre-cardial position E mandibles with left palpus, caudal aspect F maxillula, caudal. Scales omitted from objects A-C, E, F but not from eyeplate in panel C; pore diameters not to scale in C, D.

Figure 8. Holotype of Mysidetes illigi, subadult female BL 12.7 mm A body, lateral, most thoracic endopods broken (specimen artificially separated from background) B anterior body region, dorsal, cuticle lifted from cornea as fixation artefact C cephalic region, ventral D detail of (C) showing distal margin of right antennular trunk, arrows point to mid-dorsal lobe (female antennular lobe = derivate of appendix masculina).