Unravelling the conoidean gastropods assigned to the genus Propebela (Gastropoda: Mangeliidae) from south-western Atlantic deep waters Author Sánchez, Noelia Author Damborenea, Cristina Author Pastorino, Guido text Journal of Natural History 2023 2023-03-06 57 1 - 4 243 256 http://dx.doi.org/10.1080/00222933.2023.2174056 journal article 53796 10.1080/00222933.2023.2174056 ffa72bdd-2709-4632-8e22-1ab755027e87 1464-5262 7741558 Notopropebela profunda ( Castellanos and Landoni, 1993 ) comb. nov. ( Figure 1 (a–k), Table 2 ) Propebela profunda Castellanos and Landoni, 1993: 16 , pl. 1, fig. 7; Linse 1999: 402 ; Signorelli et al. 2015: 62 , fig. 5E, F. Oenopota profunda – Figueira and Absalão 2010: 475 . Examined material. Three shells with locality ′ South Atlantic ̍ (MACN-In35153) and one dry specimen (MLP-Ma15507) from 46°S , 60°W , at 600 m depth , San Jorge Gulf , Off Santa Cruz Province , Argentina ( type locality) . Description. Shell ( Figure 1 (a–f)) very small (up to 5.9 mm height), whitish in colour, somewhat shiny; rhomboid profile; spire short; protoconch smooth, globose ( Figure 1 (g–j)), paucispiral of 1¾ whorls, about 0.6 × 0.9 mm height and width, respectively; protoconchteleoconch boundary clearly defined; teleoconch of 3 slightly convex whorls; subsutural ramp faintly concave; suture moderately deep. Axial ornamentation of regularly spaced fine riblets ( Figure 1 (k)), 13 on 1st, increasing to 50 on 2nd and up to 52 on last whorl. Spiral ornamentation of weak cords, visible after 2nd whorl, 5 on 2nd, conspicuous below mid whorl, very weak near suture, 55 on last whorl. Anal sinus shallow on subsutural ramp. Columellar callus very thin and narrow. Siphonal canal short. Aperture oval-elongate. Figure 1. Notopropebela profunda ( Castellanos and Landoni, 1993 ) comb. nov. (a–b) MACN-In35153, South Atlantic, two views of the shell. (c–d) MLP-Ma15507, 46°S, 60°W, 600 m, San Jorge Gulf, off Santa Cruz Province, two views of the shell. (e–i) MACN-In35153; (e–f) two views of the shell; (g) lateral view of the protoconch; (h) detail of the same protoconch; (i) apical view of the protoconch; (j) other lateral view of the same protoconch; (k) detail of the same shell showing the ornamentation on the teleoconch. Scale bars: a–f = 2.0 mm; g = 500 µm; h, k = 100 µm; i, j = 1 mm. Distribution. Only known from type locality and a unique lot (MACN-In35153) labelled ′South Atlantic̍. Remarks. The axial ornamentation of numerous fine riblets and weak spiral cords characterise this species. None of the collected specimens include soft parts, so the radula remains unknown. The measurements and the locality of the specimens deposited at MACN do not match those described by Castellanos and Landoni (1993) , as noted by Tablado and Mantinian (2004) . Therefore, the material housed at MACN cannot be considered part of the type series. Forcelli et al. (2015 , p. 204, pl. 6, fig. 1) illustrated one shell as Propebela profunda , which is considered a different undescribed species (Sánchez and Pastorino in preparation).