Melanella sarissa ( Watson, 1883 )

Souza, Leonardo Santos De, Pimenta, Alexandre Dias & Barros, José Carlos Nascimento De, 2021, Revision of the deep-sea Eulimidae (Gastropoda, Caenogastropoda) from off Northeast Brazil, Zootaxa 4927 (4), pp. 451-504 : 474-476

Melanella sarissa ( Watson, 1883)

( Figure 12 A–L)

Eulima sarissa Watson, 1883: 119–120 .

Eulima sarissa: Watson (1886 : plate 37, figure 6a–b).

Melanella cinca Dall, 1927: 65 . syn. nov.

Melanella sarissa : Lange-de-Morretes (1949: 83); Rios (1994: 104, plate 34, figure 430 [reproduced from original illustration]); Rios (2009: 192, figure 471 [reproduced from original illustration]).

Type material. Holotype NHMUK 1887.2 .9.1599 ( Figure 12 A–B). Melanella cinca Dall, 1927 : Syntype USNM 108028 ( Figure 12D ), USFC stn. 2668, off Georgia, USA .

Type locality. Brazil: off Pernambuco, Challenger stn. 122 .

Material examined. Type material; USA: USFC stn. 2668: USNM 108036 b [4 dd], USNM 108036 h [2 dd]; USFC stn. 2415 (30°44′N 79°26′W, 805 m), coll. 01/iv/1885: USNM 108379 b [1 dd] . Puerto Rico: North of Culebra Island, off St. Thomas , Challenger stn. 24: NMW 1955.158 .26254 [1 dd] ; Brazil: Pernambuco: Challenger stn. 120 (08°37′S 34°28′W, 1234 m), coll. 09/ ix/1873: NMW 1955.158 .00652 [3 dd]; Rio de Janeiro state, continental slope of Campos Basin: Oceanprof I stn. 44: IBUFRJ 19708 † [1 dd]; (22°22′37″S 40°06′28″W, 650 m), coll. RV Gyre, 22–24/viii/2009: MNRJ 28845 † [1 dd] .

Measurements. Holotype NHMUK 1887.2.9.1599, 10 whorls, SL= 4.0 mm; BWL= 1.7 mm; AL= 1.1 mm; SW= 1.2 mm; AW= 0.7 mm. NMW 1955.158.26254, 10 whorls, SL= 4.0 mm; BWL= 1.8 mm; AL= 1.2 mm; SW= 1.2 mm; AW= 0.7 mm. MNRJ 28845, 10 whorls, SL= 3.8 mm; BWL= 1.8 mm; AL= 1.0 mm; SW= 1.2 mm; AW= 0.6 mm. IBUFRJ 19708, 9 whorls, SL= 3.5 mm; BWL= 1.7 mm; AL= 1.1 mm; SW= 1.1 mm; AW= 0.6 mm. Syntype of M. cinca, USNM 108028, 8 whorls, SL= 2.5 mm; BWL= 1.1 mm; AL= 0.7 mm; SW= 0.8 mm; AW= 0.5 mm.

Remarks. Watson (1883) only reported material from Challenger stn. 122 in the original description. A survey in the NMW revealed other specimens of M. sarissa collected from Challenger stn. 24 (NMW 1955.158.26254), in Puerto Rico, and stn. 120 (NMW 1955.158.00652), in Pernambuco, but as they are from different localities, we do not include them in the type series. Thus, the shell of NHMUK 1887.2.9.1599 may be inferred as the holotype by monotypy.

Shell features of Melanella sarissa fits the wide concept of the genus Melanella , however one specimen from MNRJ 28845 ( Figure 12E ) with a well-preserved shell shows brownish spiral bands at the suture of the protoconch. The holotype of M. sarissa is also well-preserved but has no color pattern. Nevertheless, the specimen from MNRJ 28845 ( Figure 12E ) fits perfectly in shape and size with the type of M. sarissa . Species of Melanella are usually glassy and lack brownish bands, but we maintain this classification for now.

This species remained for decades without citations in the literature, Lange-de-Morretes (1949) listed Melanella sarissa in his catalogue of Brazilian mollusks based only on the original description. Rios (1970, 1975, 1985) did not list M. sarissa in his catalogues and included the species only in the most recent editions ( Rios 1994, 2009). Melanella sarissa is rediscovered after more than a century, with new records from the southeast Brazil. Melanella cinca Dall, 1927 ( Figure 12D ), only known from the type locality off Fernandina, Florida, is a junior synonym of M. sarissa . The holotype of M. cinca is a young specimen but has a similar outline of the initial whorls and dimensions ( Figure 12D ), including the protoconch ( Figure 12L ). Besides these features, the aperture is also similar in shape to the specimens of M. sarissa from Brazil. Thus, the geographic distribution of M. sarissa is greatly enlarged, occurring from Florida, USA to Rio de Janeiro, Brazil.

Based on the new material reported here, we can add to the original description that M. sarissa has 4.0 protoconch whorls, with a maximum diameter and height of 340 µm and 470 µm, respectively. Otherwise, the whole shell lacks microscopic sculpture, incremental scars are present and appear at irregular intervals, and the body whorl comprises about 45% of the shell length.

Melanella sarissa resembles M. hians ( Figure 9J ) but differs by the proportionally smaller length (holotype of M. sarissa , ~10 whorls, SL= 4.0 mm vs. syntype of M. hians NHMUK 1887.2.9.1588, 10 whorls, SL= 10.01 mm).

Melanella sarissa has similar dimensions to M. ira Dall, 1927 , from off Georgia and Fernandina, USA, but differs by being more conical and by the larger lateral expansion of the aperture.

Geographical distribution. USA: Georgia ( Dall 1927); Puerto Rico (present study); Brazil: Pernambuco ( Watson 1883) and Rio de Janeiro (present study).

Bathymetric distribution. From 538 m to 806 m.

Figures

FIGURE 9. A–I. Eulimacrostoma phorcys sp. nov. A, B. Holotype, MNRJ 23191. C–I. Paratype, MNRJ 35191. J. Melanella hians: syntype of Eulima hians Watson, 1883, NHMUK 1887.2.9.1588. E. Detail of teleoconch surface. H. Detail of protoconch, frontal view. I. Detail of protoconch, apical view. Scale bars: A–D, I= 1.0 mm; E= 200 µm; F, G= 500 µm; H= 100 µm. Credits: J, courtesy of NHMUK

FIGURE 12. A–L. Melanella sarissa (Watson, 1883):A, B. Holotype of Eulima sarissa Watson, 1883, NHMUK 1887.2.9.1599; C. NMW 1955.158.26254. D, L. Syntype of Melanella cinca Dall, 1927, USNM 108028. E. MNRJ 28845. F–K. IBUFRJ 19708. J. Detail of protoconch, frontal view; arrow indicates transition protoconch-teleoconch. K, L. Detail of protoconch, apical view; arrow indicates transition protoconch-teleoconch. Scale bars: A–G= 1.0 mm; H, I= 200 µm; J= 100 µm; K= 50 µm; L= 75 µm. Credits: A, B, courtesy of NHMUK; C, courtesy of NMW; D, L, courtesy of USNM.