Acteon, Montfort, 1810
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publication ID |
978-2-85653-614-8 |
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persistent identifier |
https://treatment.plazi.org/id/03D087B2-FFC6-BE0D-FF01-701AF39BFA94 |
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treatment provided by |
Felipe |
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scientific name |
Acteon |
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n. sp. |
“ Acteon View in CoL “ rhektos n. sp.
Figs 16E, F, 17C, 18
TYPE MATERIAL. — Holotype MNHN 20317 and 13 paratypes MNHN 20318-20320, 2 paratypes LACM 2983 About LACM .
TYPE LOCALITY . — Tonga, 20°42’S, 174°54’W, 650-676 m [ BORDAU 2 : stn DW 1553 ] GoogleMaps .
MATERIAL EXAMINED. — North of New Caledonia. BATHUS 13°21’S, 176°08’W, 415-420 m, 13 dd; stn DW 608 , 13°22’S, 4: stn DW 914 , Grand passage, 18°49’S, 163°15’E, 600-616 m, 176°08’W, 440-458 m, 1 dd GoogleMaps .
1 dd. Tonga. BORDAU 2: stn DW 1509, Tongatapu, 21°05’S, New Caledonia proper. BIOCAL: stn DW 46, 22°53’S, 175°22’W, 456-510 m, 1 dd; stn DW 1531, Eua, 21°12’S, 167°17’E, 570-610 m, 2 dd, paratypes; stn DW 77, 22°15’S, 174°56’W, 970-983 m, 2 dd, paratypes ( LACM 2983); stn DW 167°15’E, 440 m, 1 dd. 1538, 21°39’S, 175°19’W, 471-508 m, 1 dd; stn DW 1548, S of Fiji. BORDAU 1: stn DW 1488, 19°01’S, 178°25’W, 500-516 m, Nomuka Islands, 20°38’S, 175°03’W, 476-478 m, 1 dd; stn DW 1 dd, paratype ( MNHN 20319). 1553, 20°42’S, 174°54’W, 650-676 m, 4 dd, holotype ( MNHN Wallis Island. MUSORSTOM 7: stn DW 601, 13°19’S, 176°17’W, 20317; Figs 16E, 17C) and paratypes ( MNHN 20318); stn DW 350 m, 7 dd, paratypes ( MNHN 20320; Fig. 16F); stn DW 604, 1586, Vava’u Islands, 18°34’S, 173°55’W, 440-487 m, 4 dd.
DISTRIBUTION. — Known from New Caledonia, Fiji, Wallis Island and Tonga (Fig. 18), in 350-970 m.
DESCRIPTION. — Shell morphology. Length 6 mm, width 3 mm (holotype). Shell thin, oval, with convex sides (Fig. 16E). Body whorl very large, about 5/6 of the shell length. Spire short with 2-3 whorls. Suture slightly channeled. Protoconch globose, about 0.8 whorl and 500 Μm in diameter (Fig. 16F). Umbilicus closed. Aperture wide and long, wider anteriorly, about 3/4 of the body whorl length. Columellar margin slightly thickened, short, with a small fold. Sculpture of several punctuated spiral grooves (Fig. 17C). The punctuations are small, oval, and separated from each other within each groove. The grooves are separated by gaps, several times wider than the grooves. There is a large area with no grooves on the posterior 1/4 of the spire. Near the suture there are 1-3 compressed spiral grooves with punctuations similar in size and shape to those present in the other grooves. Colour pale brown with a lighter area near the suture on the posterior end of the spire.
Anatomy. Unknown. All shells collected lacked soft parts.
REMARKS. — “ Acteon ” rhektos resembles Bathyacteon aequatorialis (Thiele, 1925) in having a fragile shell with narrow, separate spiral grooves, composed of small, oval punctuations. Differences between these two species include the smaller number of spiral grooves in Bathyacteon aequatorialis , which are more separate and present no large gaps, and the colour, which is pale brown with a lighter area near the suture in “ A. ” rhektos and uniformly whitish in Bathyacteon aequatorialis . There are no other Indo-Pacific species of Acteonidae with a similar shell morphology.
A definitive generic placement for this species is not possible until complete specimens become available for study.
ETYMOLOGY. — From the Greek rhektos (brittle, breakable), in reference to the thin shell.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.