Cerithiopsis nimia, Pimenta & Faria & Figueira & Fernandes, 2024

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 : 20-22

Cerithiopsis nimia sp. nov.

urn:lsid:zoobank.org:act:22884043-7B0B-409F-A356-E98241F6A696

( Fig. 8 )

Type material. Holotype: MNRJ 30000 . Paratypes: Brazil: -- Espírito Santo State: REVIZEE– Central sta. C1– VV38: IBUFRJ 14140 [5], IBUFRJ 20647 [3]; -- Rio de Janeiro state: 22°42ʹS, 40°40ʹW, 110 m, 2007: MNRJ 31361 [1]; HAB 13 sta. H4: MNRJ 16253 [8]; HAB 16 sta. B4: MNRJ 16514 [4], MZSP 131831 [3]; type locality: MNRJ 16261 [13].

Type locality: Brazil, off Rio de Janeiro state, continental shelf of Campos Basin , HAB 11 sta. G3, (22°03ʹ41ʺS, 40°10ʹ05ʺW, 75 m)

Additional material. Brazil: -- Espírito Santo state: REVIZEE– Central sta. C1–VV38: IBUFRJ 12903 [2], IBUFRJ 20645 [12]; REVIZEE– Central sta. C1–VV24: IBUFRJ 13896 [2]; REVIZEE– Central sta. C6–Y7: IBUFRJ 19625 [9], IBUFRJ 19624 [6]; HAB 17 sta. I4: MNRJ 16526 [1*]; HAB 17 sta. I2: MNRJ 16525 [3*]; -- Rio de Janeiro state: REVIZEE– Central sta. C1–D3: IBUFRJ 19632 [2]; HAB 13 sta. H3: MNRJ 16262 [3*p]; HAB 16 sta. H3: MNRJ 16523 [8*]; HAB 13 sta. H2; MNRJ 16260 [2*]; HAB 16 sta. H2: MNRJ 16522 [2*]; HAB 13 sta. H1: MNRJ 16254 [1*]; HAB 16 sta. H4: MNRJ 16524 [2*]; HAB 11 sta. G3: MNRJ 26893 [19*]; HAB 16 sta. G3: MNRJ 16519 [19*]; HAB 16 sta. G4: MNRJ 16520 [2*]; HAB 16 sta. G5: MNRJ 16521 [1*]; HAB 16 sta. D5: MNRJ 16518 [3*]; HAB 16 sta. C3: MNRJ 16516 [1*]; HAB 11 sta. C5: MNRJ 16256 [2*]; HAB 11 sta. C4: MNRJ 16258 [4*]; HAB 16 sta. C4: MNRJ 16517 [3*]; HAB 11 sta. B4: MNRJ 16257 [2*]; HAB 16 sta. B5: MNRJ 16515 [3*]; HAB 11 sta. A5: MNRJ 16171 [1*]; 23°05ʹ23ʺS, 40°58ʹ55ʺW, 100 m, 17/ix/2004: MNRJ 31353 [3*]; 22°42ʹ34ʺS, 40°40ʹ84ʺW, 110–120 m, 19/ix/2003: MNRJ 31357 [4*]; 22°42ʹS, 40°40ʹW, viii/2002: MNRJ 31366 [2*]; 22°42ʹS, 40°40ʹW, ii/2001: MNRJ 31364 [1*]; 22°42ʹS, 40°40ʹW, iii/2007: MNRJ 31713 [1*]; 23°04ʹ14ʺS, 40°59ʹ31ʺW, 17/xii/2004: MNRJ 33008 [43*].

Etymology. From the Latin word nimius = too much, excessive. This species is named after its abundant occurrence in the material studied.

Diagnosis. Protoconch with a thin spiral cord above the suture; adapical and median spiral cords of teleoconch very close to each other, but not fused; protoconch lightly colored, teleoconch brown to light cream; thick subperipheral and basal cords.

Description. Shell elongated, conical, reaching 4.6 mm long, 1.3 mm wide, ratio length/width 3.2–3.6. Protoconch conical or subcylindrical, light cream to translucent white, 410–490 μm long, 274–309 μm wide, with 4.5–5.0 whorls of convex outline; embryonic shell dome-shaped, smooth; larval shell with microscopic granules in the sutural region and an irregular, thin spiral cord above suture (with a distance of 11–19% of whorl length), emerging in the second whorl of protoconch and disappearing 1.0–2.5 whorls after; spiral cord formed by irregularly-aligned elongated granules or by a continuous cord. Teleoconch with up to 8.5 whorls of convex to rectilinear outline; color brown to cream; sculpture formed by three spiral cords with pointed, medium-sized nodules (occupying 48–57% of body whorl length), and around 16 orthocline axial ribs on the body whorl; adapical and median spiral cords very close in initial whorls but not fused, with the three cords becoming equidistant in the body whorl; adapical spiral cord less prominent in the initial whorls, reaching a similar size than other cords in the sixth/seventh whorl; suture distinct, somewhat channeled; subperipheral spiral cord smooth, often thick; base concave, with a smooth basal cord, followed by two spiral threads considerably weaker and microscopic spiral striae; aperture ovate, 0.44–0.74 mm long, 0.36–0.61 mm wide, ratio length/width 1.2; short and open anterior canal, wide or acute posterior sinus; inner lip slightly projected over the parietal wall; outer lip crenulated by nodules projection.

Remarks. Cerithiopsis nimia sp. nov. ( Fig. 8A–J ) and Cerithiopsis rabilleri ( Fig. 7 ) are sympatric on the continental shelf of southeastern Brazil, but C. nimia is much more abundant in the material studied. These species present similar shell shape, color, and sculpture. The main difference relies in the protoconchs, mainly smooth in both, but C. nimia shows a distinct spiral cord and microscopic granules ( Fig. 8G–J ).

Minor differences are found in the teleoconch sculpture. In C. nimia , the adapical spiral cord remains smaller than the median and abapical cords through most whorls, whereas in C. rabilleri the adapical cord develops quicker. In C. nimia , the adapical and median spiral cords of the teleoconch are slightly closer to each other in relation to the abapical one ( Fig. 8E ), except at the body whorl, where the cords are equidistant; therefore, in the initial whorls of the teleoconch, the axial ribs between those two cords are very inconspicuous. In C. rabilleri , despite the slight proximity between adapical and median spiral cords, the three cords are almost equidistant and the axial ribs between adapical and median cords are clearly visible in the initial whorls. Additionally, in C. nimia the adapical spiral cord projects over the suture above ( Fig. 8E ), almost covering it.

The proximity of spiral cords (adapical and median) of C. nimia occurs in several degrees in other Cerithiopsis species, including those recorded by Figueira & Pimenta (2008) from Brazil: C. capixaba , C. fusiformis , C. prieguei , C. balaustium , C. aimen , also discussed below. Of those, the most similar is C. aimen ( Fig. 20A–D ), in which the nodules of the adapical and median spiral cords are close to each other, but never fused, and are clearly separated in the first initial teleoconch whorls.

Geographic and bathymetric distribution. From Espírito Santo to Rio de Janeiro states, in the Tropical Southwestern Atlantic Province . From 26 m to 149 m.

Figures

FIGURE 7. Cerithiopsis rabilleri Cecalupo & Perugia, 2020. A–C, F: shells from Rio de Janeiro state (A: MNRJ 17367; B–C: MNRJ 16268; F: MZSP 155541); D–E, G–J: shells from Bahia state (IBUFRJ 20651); G: body whorl of shell in D; H–I: protoconchs of shells in D and E, respectively; J: detail of sculpture of protoconch in I. Lengths of whole shells: A: 3.0 mm; B: 3.0 mm; C: 3.0 mm; D: 3.7 mm; E: 3.0 mm; F: 3.1 mm. Scale bars: A–F: 1 mm; G: 500 μm; H–I: 200 μm; J: 50 μm.

FIGURE 8. Cerithiopsis nimia sp. nov. A: holotype, from Rio de Janeiro state (MNRJ 30000). B–J: paratypes from Rio de Janeiro state (B: MNRJ 31361; C–G, I: MNRJ 16261; H, J: MNRJ 16253); E: detail of teleoconch sculpture of shell in D; F: body whorl of shell in D; G–I: protoconch and detail of shell in D; H–J: protoconch and detail. Lengths of whole shells: A–B: 2.8 mm; C: 2.7 mm; D: 2.8 mm. Scale bars: A–D: 1 mm; E: 500 μm; F: 200 μm; G–H: 100 μm; I–J: 50 μm.

FIGURE 20A–D. Cerithiopsis aimen Rolán & Espinosa, 1996. Shell from Rio de Janeiro state (MNRJ 16531). FIGURE 20E–H. Cerithiopsis prieguei Rolán & Espinosa, 1996. Shell from Rio de Janeiro state (MNRJ 32617). FIGURE 20I–L. Cerithiopsis balaustium Figueira & Pimenta, 2008. Shell from Rio de Janeiro state (MNRJ 16527). C, G, K: protoconch of shells in B, F and J, respectively; D: detail of teleoconch whorls of shell in B; H, L: detail of protoconch sculpture of protoconchs in G and K, respectively. Lengths of whole shells: A–B: 1.8 mm; E–F: 2.4 mm; I: 1.8 mm; J: 1.7 mm. Scale bars: A–B, E–F, I–J: 1 mm; C–D, G–H, K–L: 100 µm.