Aclis marplatensis ( Castellanos & Landoni, 1984 ) 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 : 476-477

Aclis marplatensis ( Castellanos & Landoni, 1984) comb. nov.

Fig. 13

Turritellopsis marplatensis Castellanos & Landoni, 1984: 293 , Figs. 2-4 : Absalão et al. (1996: 59, Figs. 2–3 ); Absalão & Pimenta (2005: 35. pl. 12, Fig. 95); Absalão et al. (2006: 235); Rios (2009: 114, Fig. 278); Signorelli et al. (2015: 65, Fig. 6 ).

Type material. (see Signorelli et al. 2015 for notes and illustrations of the type material). Holotype: MACN-In 28924 . Paratypes: Argentina: from the type locality: MACN-In 28294-1 [1].

Type locality. Argentina: Buenos Aires province: Mar del Plata , Chapadmalal; N. Landoni leg. , 1976.

Material examined. Brazil: Bahia state: Royal Charlote Bank Revizee Central V sta. 07r: IBUFRJ 14050 [1†]; Bank, Revizee Central V sta. 07r: IBUFRJ 14050 [1†]. Espírito Santo state: South edge of Abrolhos Shelf, Revizee Central V sta. 25a: IBUFRJ 14008 [1†]; Vitória-Trindade Chain: Jaseur Bank, Revizee Central V sta. 23r: IBUFRJ 13998 [1†]; Rio de Janeiro state: HAB 11 sta. D2: MNRJ 15962 [3†]; MNRJ 16969 [1†]; HAB 11 sta. E3: MNRJ 15963 [3†]; MNRJ 16851 [1†]; HAB 11 sta. E2: MNRJ 15964 [1†]; MNRJ 16583 [3†]; HAB 11 sta. A1: MNRJ 15965 [1†]; HAB 11 sta. F2: MNRJ 15966 [1†]; MNRJ 16582 [1†]; MNRJ 16966 [1†]; HAB 11 sta. G3: MNRJ 15968 [1†]; Macaé, Santana Archipelago ; 22°24′30″S, 41°42′30″W, 38 m; S/ B Astro Garoupa col., v/1993: MNRJ 22141 [5†]: off Rio de Janeiro; 23°49′04.20″S, 42°46′48.60″W, 225 m; R/ V Professor Wladimir Besnard col. Xi/1997; MNRJ 28195 [7†]: Campos Basin ; MNRJ 28198 [1†]; Revizee Sul sta. 6653: MNRJ 60185 [1]; PADCT sta. 6627: MNRJ 60254 [1]; Cabo Frio VII sta. 6147;: IBUFRJ 2428 [1†]; Cabo Frio VII sta. 6165;: IBUFRJ 2429 [6†]; IBUFRJ 14813 [4†]; Cabo Frio VII sta. 6199; IBUFRJ 2430 [2†]; Cabo Frio VII sta. 6198; IBUFRJ 2431 [1†]; Macaé, Cabiúnas ; S/ B Astro Garoupa col., 20/v/1993: IBUFRJ 7223 [1†]; Macaé, Santana Archipelago , sta. 9; 22°21′30″S, 41°41′W, 15 m; S/ B Astro Garoupa col., v/1993: IBUFRJ 7410 [11†]; Cabo Frio VII sta. 6194; IBUFRJ 7463 [1†]; Geomar XII sta. 76; IBUFRJ 7570 [1†]; Geomar XII sta. 125; IBUFRJ 7693 [1†]; Revizee V sta. 52f: IBUFRJ 13344 [2†]; São Paulo state: Revizee sul sta. 6656: MNRJ 28196 [1†]; Revizee sul sta. 6680: MNRJ 28197 [5†]; PADCT sta. 6631: MNRJ 60260 [1]; Revizee sul sta. 6652: MNRJ 60268 [2]; Caraguatatuba ; 23°53′097″S, 45°30′843″W, 15/ii/2001: MZSP 42037 [2]; Ubatuba , sta. 4854; 23°47′S, 44°58′W, 47 m: MZSP 85269 [3]; Ubatuba ; 23°53′S, 45°09′W, 38 m; R/ V Véliger II col., 10/x/1986: MZSP 85401 [18]; MZSP 88368 [40].

Revised description. Shell vitreous or whitish, tall, conical, with an obtuse apex, reaching about 4.1 mm long, 1.2 mm wide. Protoconch globose, subcylindrical, about 2.0 whorls, 400 μm high, smooth, transition to teleoconch marked by a gentle incremental scar. Teleoconch reaching about eight whorls, regularly convex outline; suture slightly deep, well impressed, sloping; surface glossy, presenting faint microscopic spiral striae in subsutural zone of each whorl; incremental scars strongly demarcated, appearing at irregular intervals; presence of spiral keels, emerging faintly in the first teleoconch whorl, in number of two in the initial whorls, reaching five in the body whorl of holotype. Last whorl about 40% of total length, broad; base rounded. Aperture high, elliptical in shape, about 60% of body whorl length, slightly expanded laterally, rounded and slightly advanced anteriorly, acute posteriorly; outer lip thin, orthocline, rectilinear; inner lip thin, reflected. Umbilical fissure present.

Measurements. Holotype (MACN-In 28924): 8 whorls; SL= 4.13 mm; BWL= 1.59 mm; AL= 0.91 mm; SW= 1.19 mm; AW= 0.67 mm. MNRJ 15964: 8 whorls; SL= 3.62 mm; BWL= 1.41 mm; AL= 0.83 mm; SW= 1.03 mm; AW= 0.64 mm.

Remarks. The present species was originally described in the genus Turritellopsis G.O. Sars, 1878 ( Castellanos & Landoni 1984), which was included in Turritellidae until Warén (1996) transferred it to Mathildidae based on anatomical characteristics studied by him and by Haszprunar (1988).

The type species of Turritellopsis , Turritellopsis stimpsoni, Dall, 1919 [= Turritellopsis acicula (Stimpson, 1851) ] was revised and figured by Warén (1996). The shell has convex whorls with sharp spiral keels, similar to those present in Aclis marplatensis comb. nov. ( Fig. 13A–E ). However, T. stimpsoni presents the intervals between the spiral keels sculptured by microscopic axial threads ( Warén 1996: Fig. 28A–C) and lacks the microscopic spiral striae adjacent to the sutures. Aclis marplatensis has no axial sculpture and has the microscopic spiral striae in the intervals between the suture and the subsutural spiral cord ( Fig. 13H, I ), which leads to the new combination proposed here. The holotype of the species was recently illustrated with SEM images ( Signorelli et al. 2015: fig. 6K–L). Based on these images, it is possible to assure that there are no axial threads in the holotype compared to what was described and figured by Castellanos & Landoni (1984). The first record of the present species in Brazil was reported by Absalão et al. (1996) (as “ Turritellopsis marplatensis ”). These authors described that the shells from Brazil do not present microscopic axial sculpture, but only microscopic spiral striae as described above.

A revised description of the shell is provided here to elucidate the shell morphology of the species. The development of the spiral keels is very homogeneous in A. marplatensis , with all of them showing a similar degree of elevation from the teleoconch surface and does not vary among the specimens studied. This pattern seems robust, taking into consideration that this is one of the most abundant species studied.

Aclis marplatensis can be distinguished from Aclis eolis ( Fig. 19A–D ), Aclis floridana Bartsch, 1911 (see Peñas & Rolán 2013: pl. 2, Fig. 2A, B for illustrations of the type material), Aclis hendersoni Dall, 1927 ( Fig. 19E–F ), all from Florida, USA, and from Aclis trilineata Watson, 1897 (see Bogi et al. 2016: Fig. 1A–F , for illustrations), from Madeira and western Mediterranean, by the more pronounced spiral keels of the teleoconch and by the less expanded aperture anteriorly and laterally.

Geographic Distribution. Brazil: Bahia, Espirito Santo, Vitória-Trindade Chain, Rio de Janeiro, São Paulo ( Absalão 1996; present study); Argentina: Mar del plata ( Castellanos & Landoni 1984). From 29 to 450 m.

Figures

FIGURE 1. Terminology of some of the shell features used in descriptions in the present study. A. Microscopic spiral striae of the teleoconch indicated by arrows. B. Spiral keels of the teleoconch indicated by arrows. C. Umbilical fissure indicated by arrow. D. Umbilicus indicated by arrow.

FIGURE 2. Aclis sarissa Watson, 1881. A–C, E. Lectotype, NHMUK 1887.2.9.1576, herein designated; D. Paralectotype, NHMUK 1887.2.9.1576; F–I. Paralectotype, NMW 1955.158.26255; J–K. Holotype of Aclis carolinensis, USNM 83743. A, D, F, J. Shell in frontal view; B, G, K. Shell in lateral view. C, H. Shell in dorsal view. E, I. Body whorl in frontal view. Scale bars: A–D, F–H, I–J. 1 mm; E, I. 500 μm. Credits: A–E. NHMUK photographic unit; F–I. NMW.

FIGURE 3. Aclis sarissa Watson, 1881. A–B, H–K. MORG 49199. C–D. CZUFS GAS-00102. E–G. CZUFS GAS-00104. A, C, E. Shell in frontal view; square in A indicates detail in I. B, D, F. Shell in lateral view. G–H. Detail of the body whorl in frontal view. I–J. Detail of teleoconch surface; rectangle in I indicates detail in J. K. Detail of apical whorls; arrow indicates the transition protoconch–teleoconch. Scale bars: A–F. 1 mm; G–H. 500 μm; I–J. 50 μm; K. 200 μm.

FIGURE 4. Aclis watsoni Barros, Lima & Francisco, 2007. A–B. CZUFS GAS-00105. A. C. Shell in frontal view. B. Shell in lateral view. Scale bar: 1 mm.

FIGURE 6. Aclis sp. 1: MNRJ 33505. A. Shell in frontal view. B. Apical whorls: double arrows indicate microscopic and sigmoid axial line at the protoconch surface, single bottom arrow indicate microscopic spiral striae at the teleoconch surface. C. Body whorl. Scale bars: A. 1 mm; B. 200 μm; C. 500 μm.

FIGURE 13. Aclis marplatensis (Castellanos & Landoni, 1984). A, B. MZSP 85401. C. MZSP 88368. D. MNRJ 15963. E–I. MNRJ 15964. A–C, E. Shell in frontal view; rectangle in E indicates detail in H. D. Shell in lateral view. F. Detail of body whorl in frontal view. G. Detail of apical whorls. H, I. Detail of teleoconch surface; rectangle in H indicates detail in I. Scale bars: A–E. 1 mm; F. 500 μm; G. 100 μm; H, I. 20 μm.

FIGURE 19. A–D. Aclis eolis Bartsch, 1947: Holotype, USNM 573617. A. Shell in frontal view. B. Shell in lateral view. C. Detail of apical whorls. D. Detail of the body whorl in frontal view. E–F. Aclis hendersoni Dall, 1927: E, F. Holotype, USNM 333465; E. Shell in frontal view. F. Protoconch in apical view. G–H. Aclis georgiana Dall, 1927: Holotype, USNM 108020. G. Shell in frontal view. H. Protoconch in apical view. Scale bars: A, B, E, G. 1 mm; C, F, H. 200 μm, D. 500 μm. Credits: E–H. USNM.