Eulima psila Watson 1883

Eulima psila Watson, 1883

(Figure 6 A–M)

Eulima psila Watson, 1883: 112.

Eulima psila: Watson (1886: 508, plate 35, figure 1a–c).

Type material. Lectotype (herein designated): NHMUK 1887.2.9.1585 (Figure 6A).

Type locality. Puerto Rico: North Culebra Island, off St. Thomas, Challenger stn. 24 (18°38′30″N 65°05′30″W, 713 m), coll. 25/iii/1873.

Material examined. Type material; USA: Georgia: USFC stn. 2668: USNM 108031 [1 dd]; Florida: Eolis stn. 193: USNM 433355 [1 dd]; Eolis stn. 305: USNM 433360 [1 dd]; Eolis stn. 351: USNM 417633 [3 dd]; Eolis stn. 372: USNM 417532 [1 dd]; Eolis stn. 376: USNM 417541 [1 dd]; Eolis stn. 379: USNM 433085 [1 dd]; USFC stn. 2400 (28°41′N 86°07′W, 309 m), coll. 14/iii/1885: USNM 323841 [1 dd]. Barbados: St. James, Holetown (13°10′52″N 59°38′30″W), coll. F. Sander: ANSP 353545 [1 dd]. Brazil: Pernambuco: off Archipelago Fernando de Noronha, REVIZEE Nordeste (03°54′54″S 32°37′48″W), 12/x/2001: MNRJ 35203† [1 dd]; Espírito Santo: AMBES11 stn. B5: MNRJ 34490† [1 lv, destroyed for dissection]; Rio de Janeiro: REVIZEE-Central V stn. 52f (21°46′01″S 40°04′58″W, 450 m), coll. Supply Boat Astro Garoupa, 21/vii/2001: IBUFRJ 13301† [2 dd]; Campos Basin (23°16′43″S 40°59′51″W, 600 m), coll. 19/viii/2009: MNRJ 25613† [1 dd]; HAB16 stn. E5: MNRJ 16188† [1 dd]; MD55 stn. CB102 (23°07′S 42°04′W, 100 m), coll. RV Marion Dufresne, v/1987: MNRJ 25901† [2 dd]; Campos Basin (23°17′16″S 41°00′36″W, 1800 m), coll. RV Ocean Stalwart, 05/ii/2016: MNRJ 27968† [1 lv]; Cabo Frio VII stn. 6194 (24°03′36″S 44°07′36″W, 134 m), coll. RV Almirante Saldanha, 01/iv/1983: IBUFRJ 15233† [1 dd]; Campos Basin (800 m), coll. iv/2008: MNRJ 35855† [1 dd]; Santos Basin (24°11′52″S 43°15′18″W, 600 m), coll. 28/x/2002: MNRJ 35925† [3 dd]; S„o Paulo: REVIZEE Sul stn. 6678: MNRJ 28245† [4 lv]; REVIZEE Sul stn. 6657: MNRJ 28243† [1 lv]; REVIZEE Sul stn. 6656: MNRJ 28242† [2 lv]; Rio Grande do Sul: REVIZEE Sul stn. 6858: MORG 42540† [1 dd]; REVIZEE Sul stn. 6843: MORG 42448† [1 dd]; Off Rio Grande do Sul (153 m), coll. RV Atlântico Sul, v/1986: MORG 24716† [1 dd]; Off Rio Grande do Sul, stn. 1656 (33°17ʹS 50°34ʹW, 173 m), coll. RV Prof. Wladimir Besnard, 20/i/1972: MORG 17586† [1 dd].

Measurements. Lectotype NHMUK 1887.2.9.1585, 8 whorls, SL= 4.3 mm; BWL= 2.0 mm; AL= 1.4 mm; SW= 1.1 mm; AW= 0.6 mm. USNM 433360, 14 whorls, SL= 11.4 mm; BWL= 5.1 mm; AL= 3.4 mm; SW= 2.4 mm; AW= 1.5 mm. IBUFRJ 15233†, 12 whorls, SL= 8.0 mm; BWL= 3.6 mm; AL= 2.3 mm; SW= 1.6 mm; AW= 1.0 mm. MNRJ 27968†, 12 whorls, SL= 7.2 mm; BWL= 3.5 mm; AL= 2.3 mm; SW= 1.6 mm; AW= 1.0 mm. MNRJ 35203†, 11 whorls, SL= 6.6 mm; BWL= 3.3 mm; AL= 2.0 mm; SW= 1.3 mm; AW= 0.8 mm.

Remarks. Two syntypes of the present species were found in the NHMUK and NMW; the shell from the former (NHMUK 1887.2.9.1585) is the figured specimen by Watson (1886: plate 35, figure 1a–c) and is here designated as the lectotype (Figure 6A) to clarify the name of the species. The shell from the NMW, also collected at Challenger stn. 24, is not conspecific and is probably an undescribed species of Eulima known only from this locality. The latter species will be treated latter with additional material from the Caribbean. This species has slightly convex teleoconch whorls, a relatively higher aperture occupying 70% of the body whorl (vs. ~60% in E. psila), a slightly protruding outer lip and a colorless larval shell (Figure 6N, O).

The description of Watson (1883) is appropriate for the lectotype and there is no need for a redescription of the specimen. However, since the lectotype is a young specimen it is important to highlight some features of the shell based on the material examined here. Despite the differences in size of other specimens studied here, they fit perfectly with the dimensions of the protoconch (± 420 µm long, 320 µm wide) and the initial teleoconch whorls of the lectotype. They also share a brownish spiral band at the suture of the protoconch. Eulima psila reaches about 14 whorls, 11.4 mm long and 2.4 mm wide (Figure 6E); the body whorl occupies 45% of total length and the outer lip is consistently straight and orthocline in specimens at different ontogenetic stages (Figure 6G, I). The false suture occupies a small height of the whorl (1/10) and the incremental scars are weak and present at regular intervals (0.7 whorl apart). Fresh specimens usually present a faint, wide, brownish or yellowish spiral band in the last whorls (Figure 6B, C, E). The operculum is slender with faint growth lines.

This species is rediscovered after more than a century. The species was found in several localities of the western Atlantic, from Florida, USA, to Rio Grande do Sul, South of Brazil. On the Northeast coast of Brazil only a single shell was examined (Figure 6D).

The bathymetric range of Eulima psila is extensive; live specimens were collected at 60 m (MNRJ 28243†) and at 1800 m (MNRJ 27968†), but most of the empty shells were collected in depths of more than 100 m. All live collected specimens have eyes. Other species of Eulima present a wide bathymetric range, for example E. bilineata Alder, 1848, from the Northeast Atlantic and Mediterranean, which occurs from 50 to 900 m (Bouchet & Warén 1986: 320).

Other deep water Eulima from the Atlantic with a similar shell morphology are Eulima incolor (Figure 5F, G) and E. grimaldii Bouchet & Warén, 1986 (Figure 6P, Q), both from the Northeast Atlantic. Eulima psila can be distinguished from E. incolor by the presence of a brownish spiral band at the protoconch (Figure 6K) and by reaching a higher number of whorls in the protoconch (3.5 vs. 2.0 in E. incolor) (Bouchet & Warén 1986). Eulima psila differs from E. grimaldii by the straighter outer lip (Figure 6I), which is more protruding in E. grimaldii (Figure 6Q) and by the relatively less convex whorls of the protoconch (see Bouchet & Warén 1986: figure 793 for comparison).

Geographical distribution. USA: Florida (present study); Puerto Rico (Watson 1883); Brazil: Archipelago of Fernando de Noronha, Espírito Santo, Rio de Janeiro, S„o Paulo, Rio Grande do Sul (present study).

Bathymetric distribution. From 60 m to 1800 m.