Aclis multicarinata, Souza & Araújo & Pimenta, 2024

Souza, Leonardo Santos De, Araújo, Tarciso Almeida De & Pimenta, Alexandre Dias, 2024, Taxonomic review of Aclis Lóven, 1846 (Gastropoda, Eulimidae) from Brazil with notes on other congeners from the western Atlantic and Saint Helena, Zootaxa 5433 (4), pp. 451-499 : 480-481

Aclis multicarinata sp. nov.

Fig. 15

Type material. Holotype: MNRJ 28215 [†]; R/ V Professor Wladimir Besnard coll., xi/1997 - i/1998 . Paratypes: Brazil: Paraná state: Revizee Sul sta. 6699: MNRJ 2821 7 [1†]; PADCT sta. 6641 (23°35′49″, 41°42′25″, 143 m): MNRJ 28216 [1†]. off Itajaí ; 26°38′45″S, 46°51′54″W, 150 m; ii/2004: MNRJ 36004 [1†].

Type locality. Brazil: Santa Catarina state: PADCT sta. 6635 ; 27°10′23″S, 47°27′33″W, 129 m.

Etymology. From the Latin adjective multus, meaning many, and carinatus, meaning keeled; referring to the plethora of spiral keels.

Description. Shell tall, conical, spire angle 14°, reaching about 4.2 mm long, 1.2 mm wide, eight whorls, whitish. Protoconch globose, apex dome-shaped, about 3.0 whorls, 315 μm high, surface smooth. Teleoconch with moderately convex whorls, moderately convex outline, crenulated; suture slightly deep; presence of microscopic spiral striae near suture; presence of sharp, pronounced spiral keels, first teleoconch whorl smooth, two spiral keels emerging at second whorl, remaining whorls with a progressive number of keels, reaching seven at the body whorl; incremental scars strongly demarcated, appearing at irregular intervals. Body whorl about 40% of the total length, base crenulated; aperture high, about 55% of body whorl length, rounded anteriorly, acute posteriorly; outer lip thin, sinuous, slightly advanced close to distal area; inner lip thin, reflected. Umbilical fissure present.

Measurements. Holotype, MNRJ 28215: 8 whorls; SL= 4.2 mm; BWL= 1.6 mm; AL= 0.9 mm; SW= 1.2 mm; AW= 0.7 mm.

Remarks. Aclis multicarinata sp. nov. is conspicuous by the late development of the spiral keels that starts around the third teleoconch whorl as faint elevations ( Fig. 15E ). In the last whorls the spiral keels are more numerous and more pronounced ( Fig. 15 A−B). The body whorl of the largest specimen has six spiral keels and one beginning at the basal region ( Fig. 15C, H ).

In addition to the features cited above, A. multicarinata sp. nov. can be distinguished from A. marplatensis comb. nov. by having a higher number of microscopic spiral striae, a more circular aperture, and a more advanced outer lip in the distal region; from A. anaglyptica sp. nov., by having a smaller interval between the spiral cords, a more rounded outline of the teleoconch whorls and a less expanded aperture anteriorly.

Aclis multicarinata sp. nov. resembles A. maestratii Poppe & Tagaro, 2016 , from the Philippines, but it differs by the late development of the spiral keels, which starts consistently since the beginning of the teleoconch in A. maestratii . Besides that, A. multicarinata sp. nov. has less pronounced spiral keels and a wider interval between the suture and the first spiral keel.

Geographic Distribution. Brazil: Santa Catarina, Paraná. From 129 m to 150 m.

Figures

FIGURE 15. Aclis multicarinata sp. nov. A–C, E–H: Holotype, MNRJ 28215. D: MNRJ 36004. A, B,D. Shell in frontal view; square in B indicates detail in G. C. Shell in lateral view. E–F. Detail of apical whorls. G. Detail of teleoconch surface; arrow indicates the suture. H. Detail of the body whorl in frontal view. Scale bars: A–D. 1 mm; E–F. 200 μm; G. 50 μm; H. 500 μm.