Aforia obesa, Pastorino, Guido & Sánchez, Noelia, 2016
publication ID |
https://doi.org/ 10.11646/zootaxa.4109.4.4 |
publication LSID |
lsid:zoobank.org:pub:CC0AA405-3473-4482-8DF4-DAAB18E8CB79 |
DOI |
https://doi.org/10.5281/zenodo.5616301 |
persistent identifier |
https://treatment.plazi.org/id/03D70C1D-FFF4-FFFA-8DF1-FC575AFDF9F0 |
treatment provided by |
Plazi |
scientific name |
Aforia obesa |
status |
sp. nov. |
Aforia obesa View in CoL new species.
Figures 4 View FIGURE 4 A–M; figures 5 A–E; figures 6 A–E
Description. Shell large, biconic, fusiform, young shells translucent, adults chalky white in color, up to 34 mm height; protoconch paucispiral, globose, about two whorls (~ 1.45 mm width x 2.08 mm height), irregular oblique spiral wrinkles visible; Anal sinus appears on second whorl of larval shell; transition to teleoconch gradual; teleoconch comprising 5 whorls; anal sinus at the upper third of the spire whorls and above the periphery on the last whorl, with the deepest part forming a slightly raised selenizone on the whorls, which otherwise are gently rounded and lack a keel; suture moderately deep; axial ornamentation of irregularly spaced growth lines all along shell; spiral ornamentation of fine, gently, undulating spiral threads increasing in number, 5 in the first whorl, 8 on second and third whorl, 17 on the fourth and up to 90 on the last whorl below selenizone; above selenizone, 7 in the first whorl, 8 on second and third to 11 on the fourth and fifth whorls; anterior siphonal canal narrow and very long; aperture elliptical.
Operculum oval (juveniles) or oval elongated (adults), with subterminal nucleus, brownish, translucent.
Radula of type 3 “ Turridae ” according to Kantor & Taylor (2000), short, rachidian unicuspid, with curved base, faint secondary denticles at both sides of central cusp, each one showing continuity towards the base, marginal teeth duplex with a flat major element; accessory limb robust, thick, base attached to radular membrane and major element. Penis long and broad, flat with large conical terminal papilla surrounded by a thin collar. Eyes large as in A. goniodes . Table 3 View TABLE 3 summarizes shell measurements of the new species.
Type material. Holotype, MACN-In 40475, ( Figure 4 View FIGURE 4 A–C), Paratypes, MACN-In 40476, 40477, 40478, 40479; MLP-Ma 14176; CNP-Inv 2048.
Type locality. 38°01.631'S, 54°30.275'W in 997 m depth, collected on May 26 2013, St. 41 “ Talud Continental ” expedition of R/V “PUERTO DESEADO”.
Etymology. obesa : fat in Latin, in relation to the thick profile in the last whorl of the shell.
Material examined. All specimens collected on “ Talud Continental ” expedition of R/V “PUERTO DESEADO”: MACN-In 40476, St. 8, 37°57.857´S, 54°57.406´W, in 647 m, 5 SH, 1 SP; MACN-In 40477, St. 10, 37°59.706´S, 54°41.854´W in 852 m, 1 SH, 1 SP; MACN-In 40479, St. 14, 38°0.984´S, 54°30.326´W in 1006 m, 10 SH, 6 SP; MACN-In 40480, St. 43, 37º53.837´S, 54º30.458´W, in 998 m depth, 3 specimens; MACN-In 40478, St. 44, 37°53.557'S, 54°42.941'W in 780 m, 2 SH, 1 SP; MACN-In 40481, St. 59, 37°49.688'S, 54°5.236'W in 1398 m, 2 SH; MLP-Ma 14176, St. 41, 38°01.631'S, 54°30.275'W in 997 m, 3 SH, 4 SP; CNP-Inv 2048, St. 44, 37º53.557´S, 54º42.941´W, in 780 m depth, 2 SP.
Distribution. Only known from localities around the Mar del Plata Submarine Canyon in 647 to 1,398 m depth.
Remarks. This species can be distinguished from all other Atlantic representatives of Aforia by the lack of a distinct keel, having instead a kind of raised selenizone near the upper one-third of the spire whorls. The spiral ornamentation consists of wavy threads and no microscopic granules were present as in A. goniodes , the only sympatric species. The profile of the shell of A. obesa n. sp. looks similar to A. lepta ( Watson, 1881) from New Zealand and A. goodei Dall, 1890 from Chiloe Is., Chile. McLean (1971) considered all deep-water species from the Eastern Pacific as a synonym of A. goodei . Both the latter species are blind (as well as A. persimilis Dall ) according to Sysoev and Kantor (1987), a character truly different from the new species here described. In addition, the rachidian tooth has weak denticles at both sides of the unique central cusp, in A. obesa n. sp. a feature, which in fact, separates it from every known species of Aforia . Also, the size of the accessory limb of the marginal tooth is thicker than in A. goniodes .
Antarctic species. A. magnifica and A. multispiralis , both common Antarctic species, were studied for comparative purposes only.
TABLE 3. Measurements of Aforia obesa n. sp. in mm. AL: aperture length; AW: aperture width; SL: shell length; SPL: spire length; SW: shell width. * Holotype, ** Paratype.
Specimen | 1 | 2 | 3 | 4 | 5(Fig.4 A–C)* | 6 | 7 | 8 |
---|---|---|---|---|---|---|---|---|
St. | 8 | 8 | 14 | 14 | 41 | 41 | 43 | 43 |
SL (mm) | 36 | 30 | 37 | 39 | 40 | 35 | 35 | 37 |
SW (mm) | 11 | 11 | 12 | 13 | 13 | 12 | 11 | 11 |
AL (with canal) (mm) | 21 | 20 | 23 | 23 | 24 | 21 | 22 | 23 |
AL (without canal) (mm) | 13 | 12 | 14 | 16 | 16 | 14 | 18 | 13 |
AW (mm) | 9 | 5 | 7 | 6 | 6 | 6 | 6 | 6 |
SPL (mm) | 15 | 10 | 14 | 16 | 16 | 14 | 13 | 14 |
SW/SL (%) | 30.6 | 36.7 | 32.4 | 33.3 | 32.5 | 34.3 | 31.4 | 29.7 |
continued.
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