Notopropebela pustulata, Sánchez & Damborenea & Pastorino, 2023

Sánchez, Noelia, Damborenea, Cristina & Pastorino, Guido, 2023, Unravelling the conoidean gastropods assigned to the genus Propebela (Gastropoda: Mangeliidae) from south-western Atlantic deep waters, Journal of Natural History 57 (1 - 4), pp. 243-256 : 247-249

Notopropebela pustulata sp. nov.

( Figure 2 (a–k), Table 3 )

urn:lsid:zoobank.org:act:CA51AFD6-0C1D-49C2-91EE-BF3F7DBA3625

Etymology. The species name pustulata refers to the presence of pustules on the entire shell. It is a Latin adjective.

Type material. Holotype ( Figure 2 (a–b)),from Station 8 (MACN-In44024),and 44 paratypes:1 from Station 6 (MACN-In44025); 3 from Station 10 (MACN-In44026); 1 from Station 12 (MACNIn44027);5 from Station 14 (MACN-In44028);2 from Station 27 (MACN-In44029);1 from Station 37 (MACN-In44030); 5 from Station 39 (4 MACN-In44031 and 1 MLP-Ma15508); 1 from Station 41 (MACN-In44032); 3 from Station 43 (MACN-In44033); 4 from Station 44 (3 MACN-In44034 and 1 MLP-Ma15509);1 from Station 51 (MACN-In44035); 2 from Station 54 (MACN-In44036);3 from Station 55 (MACN-In44037);4 from Station 63 (MACN-In44038);6 from Station 89 (MACNIn44039), 1 from Station 138 (MACN-In44041) and 1 from Station E13, L172 (MACN-In44040).

Type locality. 37.9642S, 54.9567W, Station 8, ′Talud Continental̍ expedition on board R / V Puerto Deseado , collected on 8 August 2012, off Buenos Aires Province at 647 m depth .

Examined material. See Table 1 .

Description. Shell ( Figure 2 (a–d)) small, up to 10.9 mm in maximum height, whitish in colour, rhomboid in profile; spire short, less than half of total shell height; protoconch ( Figure 2 (e–h)) globose, paucispiral of 1½ whorls, about 0.6 × 0.7 mm in height and width, respectively, with spirally arranged pustules; protoconch-teleoconch boundary clearly defined; teleoconch of 3 rounded whorls, all with irregularly distributed pustules over the entire surface ( Figure 2 (i)); subsutural ramp short, slightly prominent; suture moderately deep. Axial ornamentation of regularly spaced and pronounced rounded riblets, 13 on 1st, 26 on 2nd and increasing to 32 on last whorl. Spiral ornamentation of thick cords, 10 on 1st, 14 on 2nd and increasing to 43 on last whorl. Anal sinus shallow on subsutural ramp. Columellar callus wide. Siphonal canal short. Aperture oval-elongate. Operculum absent. Cephalic peduncles without visible eyes, probably blind.

Radula ( Figure 2 (j)) of semi-enrolled marginal teeth, rachidian absent. Tooth ( Figure 2 (k)) ~110 µm long, with basal spur and short ligament.

Distribution. Only known from three areas: Mar del Plata Submarine Canyon, Bahia Blanca off Buenos Aires province, and Burdwood Bank (54°S) at depths ranging from 530 to 2845 m.

Remarks. The presence of pustules on the entire surface of the shell ( Figure 2 (i)), only visible under SEM, constitutes the main conchological difference from N. profunda ( Castellanos and Landoni, 1993) . Notopropebela pustulata sp. nov. has a larger shell than N. profunda (10.9 mm vs 5.9 mm) and N. petu sp. nov. (9.6 mm), with conspicuous and more widely spaced axial riblets and stronger spiral cords forming a cancellate appearance. In addition, the anal sinus is shallower in the new species than in N. profunda and N. petu sp. nov.

Figures

Figure 2. Notopropebela pustulata sp. nov. (a–b) Holotype, MACN-In44024, St. 8, 37.9642S, 54.9567W, off Buenos Aires Province, 647 m, two views of the shell. (c–i) Paratype, MACN- In44025, St. 6, 37.9722S, 55.1485W, 530 m; (c–d) two views of the shell; (e) apical view of the protoconch; (f) lateral view of the protoconch; (g) detail of the same shell showing the pustules on the protoconch; (h) other lateral view of the same protoconch; (i) detail of the same shell showing the pustules on the teleoconch; (j) general view of the radula; (k) detail of the teeth. Scale bars: a– d = 2.0 mm; e = 500 µm; f = 200 µm; g, k = 50 µm; h = 1 mm; i, j = 100 µm.