Simulamerelina gracilis, 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.10455637 |
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persistent identifier |
https://treatment.plazi.org/id/8E32B44C-05C8-40AB-AB26-0DE894269DF6 |
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taxon LSID |
lsid:zoobank.org:act:8E32B44C-05C8-40AB-AB26-0DE894269DF6 |
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treatment provided by |
Plazi |
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scientific name |
Simulamerelina gracilis |
| status |
sp. nov. |
Simulamerelina gracilis n. sp.
( Figs 40 View FIG ; 52B View FIG ; 53Q View FIG ; Tables 7 View TABLE ; 8 View TABLE ; 9 View TABLE )
urn:lsid:zoobank.org:act:8E32B44C-05C8-40AB-AB26-0DE894269DF6
TYPE MATERIAL. — Holotype. Tuamotu • dd (height 2.45 mm, width 1.08 mm, Figs 40 View FIG A-C, G-I; 53Q); Moruroa ; 21°46’37”S, 138°53’31”W; beached; on the sea-line; MNHN-IM-2000-38726 . GoogleMaps
Paratype. Tuamotu • 1 dd (height 2.13 mm, width 0.98 mm, Fig. 40 View FIG D-F); same locality and data as holotype; coll. MB GoogleMaps .
TYPE LOCALITY. — Tuamotu: Moruroa Atoll; 21°46’37”S, 138°53’31”W; on the sea line.
DISTRIBUTION AND SYMPATRY. — The species is known in the South Pacific Ocean from the Tuamotu (Moruroa) , from empty shells only, collected on the sea line ( Fig. 52B View FIG ).
Simulamerelina gracilis n. sp. is sympatric with S. australes n. sp. at its type locality (Moruroa) ( Table 9 View TABLE ).
ETYMOLOGY. — The name is after the appearance of the shell, from the Latin gracilis (meaning slim).
DIAGNOSIS. — Simulamerelina with large shell for the genus (> 2 mm), acute-slender, turriculate and robust. Protoconch paucispiral. Teleoconch with axial and spiral sculpture of the same strength. Axial ribs reaching the base. Teleoconch with three spiral cordlets, seven on the last whorl. Microsculpture of thin and well spaced uneven spiral threads, with sparse microgranules, in the interspaces; thinner and denser threads on the spiral cordlets. Start of 2 spiral cordlets after protoconch-teleoconch boundary. Colouration uniform white with an orange blotch before the varix.
DESCRIPTION OF HOLOTYPE
Shell ( Figs 40 View FIG A-C, G; 53Q)
Large for the genus, height 2.45 mm, width 1.08 mm height/ width ratio 2.27, slender-acute, turriculate and robust.
Protoconch ( Fig. 40H View FIG )
Paucispiral with twisted nucleus, of 1.20 convex whorls, height 0.312 mm, nucleus diameter 0.112 mm, first half whorl diameter 0.200 mm, maximum diameter 0.275 mm. Sculpture of 5-6 thin, weak and uneven spiral cordlets. Protoconch-teleoconch boundary well marked.
Teleoconch
Of 4.70 convex whorls, suture evident and impressed. Axial sculpture on the last whorl of 11 orthocline ribs, slightly prosocline, almost as broad as the interspaces, reaching the base. Spiral sculpture of same strength as axial, of non equidistant cordlets: 2 on first whorl, three on subsequent whorls, the adapical very weak and barely visible; 7 cordlets on last whorl, 3 above the aperture. Cordlet I weakest, cordlet II most prominent. Rounded tubercles at the intersections, more acute on first whorls; interspaces quadrangular. Microsculpture ( Fig. 40I View FIG ) of spaced and uneven dense spiral threads in the interspaces, thinner and denser on the cordlets, and sparse microgranules. Umbilical fissure absent. Aperture oval, height 0.85 mm, height/aperture height ratio 2.88, peristome duplicated, internally with 4-5 short and weak denticles, externally thickened by a strong and broad opisthocline varix.
Colour
Colouration uniform white with an orange blotch on the last whorl before the varix.
Operculum and soft parts
Unknown.
VARIABILITY
Only two specimens are available: the paratype has not reached complete maturity, is smaller than the holotype and has an only slightly thickened varix (see Table 8 View TABLE and Appendix 18).
REMARKS
Simulamerelina australes n. sp. differs from S. gracilis n. sp. in its less slender (maximum diameter: 0.300 - 0.366 mm vs 0.275 mm in S. gracilis n. sp.) protoconch with a single keel on the adapical fifth, and micro granules on the whole surface vaguely arranged in spiral bands vs 5-6 thin and irregular spiral cordlets in S. australes n. sp.; the less slender outline; the less spiny spiral cordlets on the first whorls, with the subsutural one (still very weak) more evident than in S. gracilis n. sp.
Simulamerelina densestriata n. sp. differs from S. gracilis n. sp. in its more pupoid outline with rather obtuse first whorls and broader base; the less robust spirals with more rounded nodules at the intersections; the more numerous axial ribs on the last whorl (13-20 vs 11-12 in S. gracilis n. sp.); the neatly opisthocline outer lip vs barely opisthocline in S. densestriata n. sp.; the broader and less slender protoconch with a maximum diameter of 0.317 -0.366 mm vs 0.275 mm in S. gracilis n. sp.
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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