Systellaspis curvispina Crosnier, 1987a

(Fig. 33 A–C, 34)

Systellaspis curvispina Crosnier, 1987a: 711, Figs. 6–8.—Crosnier 1987b: 957 (Key).— Lunina et al. 2018: 3, fig. 2 (Key). Systellaspis cristata Chace, 1986: 64 (Part), Fig. 35c.

Material examined. 3 M and 2 F, Fernando de Noronha, Abracos 2 ST# 39/ Leg.2, Midwater Tow, 800 m, 04° 52,42’ S / 034° 3,51’ W; 04° 50,86’ S / 034° 5,11’ W, 24 April 2017, MOUFPE: 18.400. 1 OF, Rio Grande do Norte, Abracos 2 ST#35, Midwater Tow, 1150 m, 04° 36,48’ S / 035° 29,86’ W; 04° 18,54’ S / 035° 32,40’ W, 20 April 2017, MOUFPE : 18.439. 3 M and 4 F, Fernando de Noronha, Abracos 2 ST#40/ Leg. 2, Midwater Tow, 440 m, 03° 31,35’ S / 032° 31,63’ W; 03° 31,51’ S / 032° 31,67’ W, 24 April 2014, MOUFPE : 18.409. 2 F, Ceará Chain, Abracos 2 ST#52A/ leg. 2, Midwater Tow, 984 m, 03° 43,26’ S / 033° 25,15’ W; 03° 42,22’ S / 033° 35,82’ W, 0 2 May 2017, MOUFPE : 18.438. 1 F, Rocas Atoll, Abracos 2 ST# 53A/ Leg. 2, Midwater Tow, 610 m, 03° 48,99’ S / 033° 59,27’ W; 03° 50,05’ S / 033° 58,74 W, 0 2 May 2017, MOUFPE : 18.446.

Diagnosis: Rostrum shorter than carapace with 10–13 dorsal teeth and 6–11 ventral teeth. Carapace with dorsal carina on posterior half of midline and with strong ventral carina and with lateral ridge extending from orbit to posterior margin. Abdomen with first somite bearing a blunt barb on anterior margin; Third abdominal somite with dorsal tooth with the tip directed upward. Telson with 20 or more dorsolateral spines (modified by Crosnier 1987a).

Distribution: Western Atlantic: Brazil (Ceará Chain (seamount), Rio Grande do Norte and Fernando de Noronha Archipelago). Indo-Pacific Oceans: Madagascar, Philippines, Indonesia (Fig. 34).

Bathymetric distribution: 140–500 m (Crosnier 1987), herein this species was found between 440–1150 m, thus extending its bathymetric distribution from deep waters.

Remarks: According to Crosnier (1987a, b), S. curvispina is closely related to S. cristata Faxon, 1893, being slightly differentiated in (characters of S. cristata in parentheses): rostrum with 6–11 ventral teeth (vs. 5–8 ventral teeth); dorsal spine on third somite well developed with the tip directed upward (vs. dorsal spine on third somite well developed with the tip not directed upward). Until the present study, only two species of Systellaspis was known in Brazilian waters: S. debilis (A. Milne-Edwards, 1881) and S. pellucida (Filhol, 1885), however, these species differ by S. curvispina in the following way (character of S. debilis and S. pelucida respectively in parentheses): carapace with two sharp longitudinal lateral carinae (vs carinae absent) and rostrum with 10–13 dorsal teeth and 6–11 ventral teeth (vs 15 dorsal and 4–10 ventral teeth; vs 11 dorsal and 5 ventral teeth). Systellapsis curvispina was previously recorded only from Indo-Pacific Oceans (Fig. 34), with few records made by Crosnier (1987a, b) in mesopelagic zones. Thus, this paper comprises the first record of S. curvispina in Atlantic Ocean (Brazilian waters).