Cerithiopsis cf. atalaya Watson, 1885

Pimenta, Alexandre Dias, Faria, Raquel Garofalo De Souza, Figueira, Raquel Medeiros Andrade & Fernandes, Maurício Romulo, 2024, Unraveling another of the ‘ Big Fiveʹ: new species and records of Cerithiopsidae from Brazil (Caenogastropoda: Triphoroidea), Zootaxa 5494 (1), pp. 1-71 : 50-51

Cerithiopsis cf. atalaya Watson, 1885

( Fig. 26 )

Material examined. Brazil: -- Pernambuco state: 08°4ʹ57ʺ, 34°43ʹ37ʺ: MNRJ 18309 [2*p]; -- Rio de Janeiro state: 22°42ʹS, 40°40ʹW, 110–120 m, viii/2002: MNRJ 31376 [2*]; 22°42ʹS, 40°40ʹW, 110–120 m, iii/2007: MNRJ 33385 [1*]; 22°42ʹS, 40°40ʹW, 110–120 m, x/2007: MNRJ 32214 [1*]; 22°42ʹS, 40°40ʹW, 110–120 m, 19/ix/2009: MNRJ 32219 [2*]; HAB 17 sta. D4: MNRJ 18734 [1*p]; HAB 11 sta. C4: MNRJ 16224 [1*]; HAB 16 sta. B4: MNRJ 18733 [1*p]; 23°04ʹS, 40°59ʹW, 17/xii/2004: MNRJ 33022 [1*p]; 23°08ʹS, 41°02ʹW, x/2008: MNRJ 32215 [1*], MNRJ 32217 [1*]; 23°13ʹS, 41°02ʹW, x/2008: MNRJ 32218 [1*]; 23°38ʹS, 41°23ʹW, x/2008: MNRJ 32216 [1*].

Remarks. The lectotype of C. atalaya Watson, 1885 was designated by Bouchet & Warén (1993: 612) from Madeira (0–90 m), northeastern Atlantic. According to Bouchet & Warén (1993), the selected lectotype (NMW 1955.158.01517) was the single shell of the syntypes with a preserved protoconch, and the remainder specimens (syntypes NMW.1955.158.01516) may not be conspecific.

Bouchet & Warén (1993) indicated intraspecific variation in the shell of C. atalaya according to geographic regions, related to protoconch shape, shell shape and color. Shells from the Alboran Sea (Mediterranean) and West Africa are conical while those from Madeira are pupoid, with intermediates in the Mediterranean. While the lectotype (https://gbmolluscatypes.ac.uk/specimens/893/Cerithiopsis-atalaya) is somewhat pupoid, shells from the Alboran Sea ( Peñas et al. 2006), Greek Mediterranean ( Manousis & Galinou-Mitsoudi 2014; Manousis et al. 2023) and in the Rockall Bank, northeastern Atlantic ( Hoffman et al. 2011) have a rectilinear shell shape. Considering this variation, shells from Brazil would be more similar to those from western Africa and the Alboran Sea ( Bouchet & Warén 1993), with a more rectilinear profile than the somewhat convex profile of the lectotype.

A very similar species, Cerithiopsis sliekeri Gofas, Freiwald & Hoffman, 2023 , was recently described from Azorean seamounts and distinguished by the strength of the adapical spiral cord in teleoconch whorls, which was described as a faint swelling below the suture, while in C. atalaya the three spiral cords are almost equally strong, with distinct beads at intersections with axial ribs. Secondarily, C. sliekeri was distinguished by its whitish teleoconch, while C. atalaya is dark brown.

The shells of C. cf. atalaya from southeastern Brazil are also similar to C. sliekeri in overall shell shape, with a more rectilinear outline, but the adapical spiral cord is not as faint as reported by Gofas et al. (2023); in most shells, the strength of the adapical cord cannot be considered distinct from C. sliekeri , especially in earlier whorls ( Fig. 26C, D ), its holotype being very similar to Brazilian shells; however, in later whorls, the shells from Brazil present a stronger adapical spiral cord than C. sliekeri ( Fig. 26A, B ).

In the Campos Basin, southeastern Brazil, C. cf.atalaya was only sampled in a depth of 92–120 m, corresponding to the lower portion of the shelf. This deeper habitat (cold waters) combined with a probable planktotrophic development could possibly enable larval exchange across the Atlantic Ocean.

Geographic and bathymetric distribution. Cerithiopsis atalaya is recorded from the eastern Atlantic (Rockall Bank, France to Angola, Madeira ) and Mediterranean , present both on the continental shelf and slope, but apparently more common at the mid-end of continental shelves, 80–587 m. From Brazil, it is only known from the Tropical Southwestern Atlantic Province (from Pernambuco and Rio de Janeiro states, 92–120 m) .

Figures

FIGURE 26. Cerithiopsis cf. atalaya Watson, 1885. Shells from Rio de Janeiro state. (A: MNRJ 33022; B: MNRJ 18733; C, G–I: MNRJ 18309; D–F: MNRJ 18734). E: body whorl of shell in D; F: protoconch of shell in C; G: protoconch; H–I: detail of protoconch sculpture. Lengths of whole shells: A: 5.9 mm; B: 5.3 mm; C: 4.0 mm; D: 3.5 mm. Scale bars: A–D. 1 mm; E–G. 100 µm; H–I. 20 µm.