Macrostylis sarsi 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 : 191

Macrostylis sarsi Brandt, 1992 nom. dub.

( Fig. 21 )

Macrostylis sarsi Brandt 1992 ; pp. 74–78, Figs 14–16 .

Type fixation. Ovigerous female, 2.0 mm length, BM(NH) 1990:40:1, by original designation.

Type locality. West Maud Rise, ANT VllI/6 station 1833–1. 65 ° 10.5’S, 0° 27.4’W; depth 4,335 m, box corer.

Type material. Only holotype available, deposited at the Natural History Museum, London.

Modified diagnosis. Body with furry coat of cuticular setules and scattered spine-like, bifid setae. Pereonite 3 posterolateral margins produced posteriorly. Pereonite 4 width subequal pereonite 5 width, lateral margins curved; posterolateral margins rounded, not produced posteriorly, posterolateral setae present. Pereonite 6 length clearly larger pereonite 5 length. Female pleotelson ovoid, waist absent. Pereopod III ischium dorsal lobe triangular. Pereopod VII length smaller pereopod VI length. Operculum elongate, length exceeding 1.5 width.

Remarks. Based on the illustrations, the holotype is not adult. It is the only specimen available. A potential synonymy with Macrostylis obscura (Brandt, 1992) is discussed above. The ventral spines have not been illustrated in the original description, as it was the case in M. obscura (Brandt, 1992) , described in the same publication, where later ventral spines were found (Riehl & Brandt 2010).

The scale provided in the habitus plate is probably incorrect: according to the description, the body should be 2.0 mm long; new measurements based on the scale provided result in a body length of 1.3 mm. All other plates have no scale and hence, re-evaluation of ratios between parts is impossible and hence, original measures were mostly applied here. The holotype carcass is gone missing, slides are available but damaged and dissected parts are mostly in bad condition or lost. Appendages available on slides are: Antennula , antenna, mandibles, pereopod I, pereopods 5–7, operculum (apex broken). The taxonomic identity of this species cannot be determined from its existing type and it is hence considered nomen dubium.

Figures

FIGURE 14. Macrostylis matildae n. sp. A – H, paratype non-ovigerous female (ZMH K- 43003). A, left mandible, dorsal, molar process damaged. B, left mandible incisor process and lacinia mobilis, medial. C, right mandible incisor process and lacinia mobilis, medial. D, right mandible, dorsal, molar process damaged, lateral seta missing. E, antennula and antenna, in situ. F, maxillula, damaged. G, maxilliped, ventral. H, maxilla. Scales: A – H = 0.1 mm.

FIGURE 15. Macrostylis matildae n. sp. A – D, paratype non-ovigerous female (ZMH K- 43003). A, pereopod I. B, pereopod II, cuticular setules omitted. C, pereopod III, cuticular setules omitted, propodus and dactylus twisted 45 °. D, pereopod IV, cuticular setules omitted. Scale: A – D = 0.2 mm.

FIGURE 16. Macrostylis matildae n. sp. A – C, paratype non-ovigerous female (ZMH K- 43003). A, pereopod V, cuticular setules omitted. B, pereopod VI, cuticular setules omitted. C, pereopod VII, cuticular setules omitted. Scale: A – C = 0.2 mm.

FIGURE 21. Macrostylis sarsi Brandt, 1992 A – H, holotype non-ovigerous female (BM (NH) 1990 - 40 - 1). A, pereopod I. B, pereopod VI. C, pereopod VII. D, operculum, apex damaged. E, antenna. F, antennula. G, right mandible, ventral. H, left mandible, ventral. Scale: A – C = 0.2 mm; D – H = 0.1 mm.