Macrostylis obscura (Brandt, 1992)

Riehl, Torben & Brandt, Angelika, 2013, Southern Ocean Macrostylidae reviewed with a key to the species and new descriptions from Maud Rise, Zootaxa 3692 (1), pp. 160-203 : 190

Macrostylis obscura (Brandt, 1992) nom. dub.

Desmostylis obscura Brandt, 1992 ; p. 70, Figs 11–13 ;

Macrostylis obscura (Brandt, 1992) ; Riehl & Brandt (2010); pp. 43–44; Fig. 19 .

Remarks. This species and the genus Desmostylis Brandt, 1992 were based on a single damaged manca. Both were subsequently transferred to Macrostylis Sars, 1864 (Riehl & Brandt 2010) . The species was collected from the same box corer sample as M. sarsi Brandt, 1992 , which is represented by a single subadult female specimen. Both species share several similarities, such as dorsal and lateral setation of the body. Quantitative samples such as boxcorer samples often show an aggregated distribution of single species, so the possibility remains that these specimens are conspecific. Unfortunately, much of each type specimen is missing owing to dissection and subsequent damage and loss at the NHM London. So the types cannot be fully compared to decide whether they are conspecific or not. Another consequence of the manca stage of the only known representative of M. obscura is that information suitable and available for comparison with other species of the family is very limited. M. obscura is therefore not included in the key presented below and is henceforward regarded nomen dubium. In accordance with the gender agreement stated in Article 31.2 of the ICZN, the species-group name is changed to be feminine.

Figures

FIGURE 11. Macrostylis matildae n. sp. A – D, holotype non-ovigerous female (ZMH K- 43000). A, habitus dorsal, cuticular setules and imbricate ornamentation (IO) omitted. B, habitus lateral, cuticular setules, IO and uropod omitted. C, pereopod III D, pleotelson, ventral. Scale: A – D = 0.2 mm.

FIGURE 12. Macrostylis matildae n. sp. A – D, paratype non-ovigerous female (ZMH K- 43005), SEM photograph. A, habitus lateral. B, cephalothorax lateral with imbricate ornamentation enlarged. C, pereopod IV, merus – dactylus D, pereopod III dactylus, posterio-lateral view. Scale: A = 0.5 mm, B = 0.1 mm, C = 0.05 mm, D = 0.01 mm.

FIGURE 13. Macrostylis matildae n. sp. A – F, paratype non-ovigerous female (ZMH K- 43003). A, habitus lateral, pereopods dissected, most setae, imbricate ornamentation (IO) and cuticular setules omitted. B, habitus, dorsal, cuticular setules, IO and right uropod setation omitted, with pleotelson tergal seta enlarged. C, operculum, ventral. D, pleopod III, dorsal, exopod setal fringe indicated by dashed line. E, pleopod IV, dorsal. F, pleopod V, dorsal. Scale: A, B = 0.5 mm, C – F = 0.1 mm.

FIGURE 19. Macrostylis matildae n. sp. A – C, paratype adult male (ZMH K- 43004). A, pereopod V, cuticular setules omitted. B, pereopod V dactylus, enlarged. C, pereopod VI, cuticular setules illustrated. D, pereopod VII, cuticular setules omitted, twisted at carpo-propodal articulation. Scale: A, C, D = 0.2 mm.