Parashiela rimatara, Amati & Giulio & Oliverio, 2023
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publication ID |
https://doi.org/ 10.5252/zoosystema2023v45a25 |
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publication LSID |
lsid:zoobank.org:pub:054D312B-C54B-459D-8A47-AC9CB681D7D4 |
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DOI |
https://doi.org/10.5281/zenodo.10455625 |
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persistent identifier |
https://treatment.plazi.org/id/F4FD4FFA-0A9C-4905-B91D-53CA21E1CCC4 |
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taxon LSID |
lsid:zoobank.org:act:F4FD4FFA-0A9C-4905-B91D-53CA21E1CCC4 |
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treatment provided by |
Plazi |
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scientific name |
Parashiela rimatara |
| status |
sp. nov. |
Parashiela rimatara n. sp.
( Figs 30 View FIG ; 51C View FIG ; 53L View FIG ; Tables 4 View TABLE ; 5; 6)
urn:lsid:zoobank.org:act:F4FD4FFA-0A9C-4905-B91D-53CA21E1CCC4
TYPE MATERIAL. — Holotype. Australes • dd (height 1.53 mm, width 1.00 mm, Figs 30 View FIG A-C, E-I, 53L); Rimatara , BENTHAUS Stn DW2021; 22°37’1”S, 152°48’36”W; 1200-1226 m; 25.XI.2002; MNHN-IM-2000-38716 . GoogleMaps
Paratype. Australes • 1 dd (height 1.33 mm, Fig. 30D View FIG ); Rimatara , BENTHAUS Stn DW2020; 22°37’1”S, 152°49’1”W; 920-930 m; 25.XI.2002; MNHN-IM-2000-38717 . GoogleMaps
TYPE LOCALITY. — Australes: Rimatara, BENTHAUS Stn DW2021; 22°37’1”S, 152°49’1”W; 1200-1226 m.
OTHER MATERIAL EXAMINED. — Australes • 1 dd; S of Rurutu ; BENTHAUS Stn DW2010; 22°31’58”S, 151°20’59”W; 520-950 m; 24.XI.2002; MNHN GoogleMaps .
DISTRIBUTION AND SYMPATRY. — The species is at present known in the South Pacific Ocean from the Australes Islands (Rimatara, Rurutu) ( Fig. 51C View FIG ), where it is sympatric with P. ambulata Laseron, 1956 (Rimatara, Rurutu) and with P. expansilabrum n. sp. (Rimatara) ( Table 5 View TABLE ).
ETYMOLOGY. — The name is based on the type locality, Rimatara Island, used as a noun in apposition.
DIAGNOSIS. — Parashiela of medium size for the genus, height c. 1.50 mm. Protoconch multispiral. Teleoconch with numerous thin axial ribs, entering the umbilical fissure; convex, non angular whorls, macro spiral sculpture of only a thin suprasutural cordlets on the first whorl, vanishing on the last whorl. Microsculpture of dense spiral threads, some thicker and more marked. Peristome duplicated, with moderately thickened varix crossed by evident growth striae.
DESCRIPTION OF HOLOTYPE
Shell ( Figs 30 View FIG A-C, E; 53L)
Medium size for the genus, height 1.53 mm, width 1.00 mm, height/width ratio 1.53, not very robust, ovate-conical.
Protoconch ( Fig. 30F, G View FIG )
Multispiral, rather acute, of 1.4 whorls, height 0.185 mm, nucleus diameter 0.625 mm, first half whorl diameter 0.125 mm, maximum diameter 0.250 mm; protoconch I devoid of sculpture, protoconch II with only a thin spiral cordlet on the lower third. Protoconch I-II boundary very weak, sinuous ( Fig. 30F, G View FIG ). Protoconch-teleoconch boundary marked, with a sinusigera notch.
Teleoconch
Of 3.6 convex whorls, with barely evident double angle on the last whorl. Axial sculpture on the last whorl of 26 thin, flexuose, orthocline ribs, reaching the base and entering the umbilical fissure. Interspaces twice or three times as wide as the axial ribs. Macro spiral sculpture of only a weak and thin suprasutural cordlet on the first whorls, vanishing already from the penultimate whorl ( Fig. 30F View FIG ). Microsculpture of groups of 5-6 fine spiral threads, alternating with some thicker and more marked ( Fig. 30H, I View FIG ). Umbilical fissure evident. Aperture round-ovate height 0.65 mm, height/aperture height ratio 2.354, peristome duplicated; outer lip orthocline, sinuous, smooth internally, scarcely thickened externally, with numerous growth striae; columellar lip slightly angled.
Colour
Whitish colouration.
Operculum and soft parts
Unknown.
VARIABILITY
Only three specimens examined, all adults, not very variable in shape, but with a remarkable variation in the number of axial ribs on the last whorl, 26, 28 and 54 ( Table 5 View TABLE and Appendix 12).
REMARKS
Parashiela ambulata Laseron, 1956 View in CoL differs from P. rimatara n. sp. in its more robust and larger shell (height 1.85 mm vs height 1.53 mm in P. rimatara n. sp.); in the whorl two medially angled with a spiral cordlet vs whorls with barely evident double angle, devoid of major spiral cordlets (only one minor suprasutural cordlet on the first whorls) in P. rimatara n. sp.; the umbilical fissure absent or very narrow, more evident in P. rimatara n. sp.
Parashiela invisibilis ( Hedley, 1899) View in CoL differs from P.rimatara n. sp. in the four spiral cordlets on the last whorl (2 above the aperture) vs only one minor suprasutural cordlet on the first whorls in P. rimatara n. sp.
Parashiela liddelliana ( Hedley, 1907) View in CoL differs from P.rimatara n. sp. in the lack of umbilical fissure, present in P. rimatara n. sp.; the smaller size (height 1.20 mm vs 1.38-1.53 mm in P. rimatara n. sp.); the fewer axial ribs with wider interspaces (c. 20 vs 26-54 in P. rimatara n. sp.).
Parashiela obesula n. sp. differs from P. rimatara n. sp. in its slightly more obtuse outline; the thinner and less acute ribs and the narrower umbilical fissure.
See under P. expansilabrum n. sp., P. rotundata n. sp. and P. soniae n. sp. for detailed comparisons.
| MNHN |
France, Paris, Museum National d'Histoire Naturelle |
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.
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