Simulamerelina australes, Amati & Giulio & Oliverio, 2023

Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2023, Shallow-water Rissoidae of the genera Alvania Risso 1826 Haurakia Iredale 1915 Parashiela Laseron 1956 Simulamerelina Ponder 1985 and Subestea Cotton 1944 Gastropoda Caenogastropoda Rissooidea from French Polynesia with the description of a new deep-water genus, Zoosystema 45 (25), pp. 803-892 : 854-860

Simulamerelina australes n. sp.

( Figs 34 ; 35 ; 36 ; 37 ; 52A ; 53O ; Tables 7 ; 8 ; 9 )

urn:lsid:zoobank.org:act:F65B297A-AEE4-4050-8B26-2386A17AA028

Simulamerelina sp. 3 , 4 – Boutet et al. 2020: 240.

TYPE MATERIAL. — Holotype. Australes • 1 dd (height 2.47, width 1.12 mm, Figs 34 ; 36 ; 53O ); Rapa , SE of Pointe Tematapu, Atelier RAPA Stn 34; 27°34’47”S, 144°19’1”W; 2-8 m; 19.XI.2002; slope in a large cave, muddy bottom; MNHN-IM-2000-38722 .

Paratypes. Australes • 500 dd; same locality data as holotype; MNHN-IM-2000-38723 .

TYPE LOCALITY. — Australes: Rapa, SE of Pointe Tematapu, Atelier RAPA Stn 34; 27°34’47”S, 144°19’1”W; 2- 8 m.

OTHER MATERIAL EXAMINED. — Australes • 2 dd; Marotiri BENTHAUS Stn DW1887; 27°52’1”S, 143°33’0”W; 750-1000 m; 6.XI.2002; MNHN • 1 dd; Marotiri, BENTHAUS Stn DW1885; 27°52’1”S, 143°33’0”W; 700-800 m; 6.XI.2002; MNHN • 3 dd; Marotiri, BENTHAUS Stn DW1886; 27°51’0”S, 143°31’58”W; 620-1000 m; 6.XI.2002; MNHN • 34 dd; E of Rapa , BENTHAUS Stn DW1889; 27°37’1”S, 144°16’1”W; 600-620 m; 7.XI.2002; MNHN • 2 dd; Rapa ; 27°37’19”S, 144°22’4”W; 5-20 m; coll. MB • 6 dd; Rapa Baie Pake Atelier RAPA Stn 82; 27°37’4”S, 144°18’28”W; 11,14. XI.2002; MNHN • 36 dd; Rapa Est de la Baia Tupuaki Atelier RAPA Stn 21; 27°34’12”S, 144°20’34”W; 5 m; 12.XI.2002; blocs de corail mort sur fond de sable; MNHN • 3 dd; Rapa Pte Pukitarava Atelier RAPA Stn 89; 27°35.9’S, 144°18.5’W; intertidal; 9.XI.2002; MNHN • 47 dd; Rapa, Anatakuri Bay, Atelier RAPA Stn 69; 27°37’47”S, 144°18’43”W; 3-4 m; 19.XI.2002; coarse sand and algae; MNHN • 115 dd; Rapa , Ahurei Bay; 27°36’57”S, 144°19’48”W; 1 m; coll. JL • 2 dd; Rapa , Ahurei Bay; 27°36’57”S, 144°19’48”W; 10-20 m; coll. MB • 30 dd; Rapa , Akatanui Bay, Atelier RAPA Stn 13; 27°36’7”S, 144°18’53”W; 2 m; 8.XI.2002; sandy pockets; MNHN • 42 dd; Rapa , Akatanui Bay, Atelier RAPA Stn 81; 27°35’52”S, 144°18’28”W; intertidal; 9.XI.2002; rocks; MNHN • 12 dd; Rapa , Anarua Bay, Atelier RAPA Stn 41; 27°36’18”S, 144°22’40”W; 5 m; 25.XI.2002; corals on sandy bottom; MNHN • 37 dd; Rapa , Anarua Bay, Atelier RAPA Stn 41; 27°36’18”S, 144°22’40”W; 5 m; 25.XI.2002; corals on sandy bottom; MNHN • 4 dd; Rapa, Anatakuri Bay, Atelier RAPA Stn 69; 27°37’47”S, 144°18’43”W; 3-4 m; 19.XI.2002; coarse sand and algae; MNHN • 1 dd; Rapa, Anatakuri Bay, Atelier RAPA Stn 69; 27°37’47”S, 144°18’43”W; 3-4 m; 19.XI.2002; coarse sand and algae; MNHN • 117 dd; Rapa, Anatakuri Nako Bay, Atelier RAPA Stn 25; 27°38’24”S, 144°18’53”W; 3 m; 13.XI.2002; blocks of dead coral on sand; MNHN • 18 dd; Rapa , Haurei Bay, Atelier RAPA Stn 47; 27°36’43”S, 144°19’4”W; 33 m; 29.XI.2002; corals on muddy bottom; MNHN • 107 dd; Rapa , Hiri Bay; 27°37’19”S, 144°22’4”W; 3-5 m; coll. JL • 1 dd; Rapa , Hiri Bay; 27°37’19”S, 144°22’4”W; 5-20 m; coll. MB • 2 dd; Rapa , Hiri Bay, Atelier RAPA Stn 9; 27°37’19”S, 144°22’12”W; 3-24 m; 6.XI.2002; amidst corals; MNHN • 85 dd; Rapa , Hiri Bay, Atelier RAPA Stn 9; 27°37’19”S, 144°22’12”W; 3-24 m; 6.XI.2002; amidst corals; MNHN • 733 dd; Rapa , N of Anatakuri Bay, Atelier RAPA Stn 38; 27°37’22”S, 144°18’25”W; 2 m; 22.XI.2002; sediment under a large rock; MNHN • 39 dd; Rapa , N of Anatakuri Bay, Atelier RAPA Stn 38; 27°37’22”S, 144°18’25”W; 2 m; 22.XI.2002; sediment under a large rock; MNHN • 112 dd; Rapa , N of Aturapa I., Atelier RAPA Stn 29; 27°34’19”S, 144°20’59”W; 4- 2 m; 15.XI.2002; dead coral; MNHN • 16 dd; Rapa , N of Rapa Iti I., Atelier RAPA Stn 11; 27°37’12”S, 144°18’10”W; 2 m; 7.XI.2002; sandy pockets amidst slabs of dead coral; MNHN • 31 dd; Rapa , N of Rapa Iti I., Atelier RAPA Stn 11; 27°37’12”S, 144°18’10”W; 2 m; 7.XI.2002; sandy pockets amidst slabs of dead coral; MNHN • 27 dd; Rapa, Nord of Pukitarava , Atelier RAPA Stn 14; 27°35’49”S, 144°13’37”W; 2 m; 8.XI.2002; dead coral blocks on sand; MNHN • 94 dd; Rapa, Nord of Pukitarava , Atelier RAPA Stn 14; 27°35’49”S, 144°13’37”W; 2 m; 8.XI.2002; dead coral blocks on sand; MNHN • 12 dd; Rapa , off Cape Rukuaga, Atelier RAPA Stn 22; 27°33’54”S, 144°21’43”W; 18-22 m; 13.XI.2002; corals on rocky bottom; MNHN • 2 dd; Rapa, off Pointe Rukuaga, Atelier RAPA Stn 48; 27°34’4”S, 144°22’4”W; 36 m; 30.XI.2002; plateau with silty sand; MNHN • 1 dd; Rapa, off Pointe Rukuaga, Atelier RAPA Stn 48; 27°34’4”S, 144°22’4”W; 36 m; 30.XI.2002; plateau with silty sand; MNHN • 1 dd; Rapa, off Pointe Rukuaga, Atelier RAPA Stn 48; 27°34’4”S, 144°22’4”W; 36 m; 30.XI.2002; plateau with silty sand; MNHN • 4 dd; Rapa , Pake Bay, Atelier RAPA Stn 61; 27°37’1”S, 144°18’36”W; 10-15 m; 11-14.XI.2002; sandy mud and coral; MNHN • 102 dd; Rapa , Pake Bay, Atelier RAPA Stn 61; 27°37’1”S, 144°18’36”W; 10-15 m; 11-14.XI.2002; sandy mud and coral; MNHN • 49 dd; Rapa, Pariati Bay, Atelier Rapa Stn 67; 27°34’40”S, 144°21’43”W; 3-4 m; 18.XI.2002; muddy sand and seaweed; MNHN • 2 dd; Rapa, Pariati Bay, Atelier Rapa Stn 67; 27°34’40”S, 144°21’43”W; 3-4 m; 18.XI.2002; muddy sand and seaweed; MNHN • 14 dd; Rapa, Pointe Kauira, Atelier RAPA Stn 36; 27°33’28”S, 144°20’49”W; 27 m; 21.XI.2002; corals, mostly alive; MNHN • 7 dd; Rapa, Pointe Komiré, Atelier RAPA Stn 10; 27°34’47”S, 144°22’47”W; 16-18 m; 7.XI.2002; rocks covered with brown algae; MNHN • 238 dd; Rapa, Pointe Komiré, Atelier RAPA Stn 10; 27°34’47”S, 144°22’47”W; 16-18 m; 7.XI.2002; rocks covered with brown algae; MNHN • 3 dd; Rapa, Pointe Mei, Atelier RAPA Stn 30; 27°38’13”S, 144°18’10”W; 16-20 m; 16-18.XI.2002; drop-off with dead corals; MNHN • 41 dd; Rapa, Pointe Mei, Atelier RAPA Stn 30; 27°38’13”S, 144°18’10”W; 16-20 m; 16-18.XI.2002; drop-off with dead corals; MNHN • 21 dd; Rapa, Pointe Mei, Atelier RAPA Stn 30; 27°38’13”S, 144°18’10”W; 16-20 m; 16-18.XI.2002; drop-off with dead corals; MNHN • 1 dd; Rapa, Pointe Mei, Atelier RAPA Stn 31; 27°38’13”S, 144°18’10”W; 6 m; 16.XI.2002; rocks; MNHN • 32 dd; Rapa, Pointe Mei, Atelier RAPA Stn 31; 27°38’13”S, 144°18’10”W; 6 m; 16.XI.2002; rocks; MNHN • 124 dd; Rapa, Pointe Pukitarava, Atelier RAPA Stn 89; 27°35’52”S, 144°18’28”W; intertidal; 9. XI.2002; MNHN • 4 dd; Rapa, Pointe Taekateke, Atelier RAPA Stn 28; 27°38’24”S, 144°20’34”W; 30 m; 15.XI.2002; rocky blocks with algal cover; MNHN • 1 dd; Rapa, Pointe Taekateke, Atelier RAPA Stn 28; 27°38’24”S, 144°20’34”W; 30 m; 15.XI.2002; rocky blocks with algal cover; MNHN • 1 dd; Rapa , Pte Maomao Atelier RAPA Stn 78; 27°36’35”S, 144°18’53”W; intertidal; 6.XI.2002; beached sediment; MNHN • 7 dd; Rapa , Rarapai I., Atelier RAPA Stn 4; 27°34’19”S, 144°22’4”W; 18 m; 4.XI.2002; rocky blocks covered with brown algae; MNHN • 10 dd; Rapa , Rarapai I., Atelier RAPA Stn 4; 27°34’19”S, 144°22’4”W; 18 m; 4.XI.2002; rocky blocks covered with brown algae; MNHN • 5 dd; Rapa , S of Anatakuri Bay, Atelier RAPA Stn 19; 27°37’40”S, 144°18’43”W; 3 m; 11.XI.2002; coral blocks on sandy bottom; MNHN • 60 dd; Rapa , S of Anatakuri Bay, Atelier RAPA Stn 19; 27°37’40”S, 144°18’43”W; 3 m; 11.XI.2002; coral blocks on sandy bottom; MNHN • 5 dd; Rapa , S of Tarakoi I., Atelier RAPA Stn 5; 27°5’34”S, 144°18’28”W; 8 m; 4.XI.2002; dead corals with algae, muddy-sandy pockets; MNHN • 19 dd; Rapa , S of Tarakoi I., Atelier RAPA Stn 5; 27°5’34”S, 144°18’28”W; 8 m; 4.XI.2002; dead corals with algae, muddy-sandy pockets; MNHN • 3 dd; Rapa , SE of Pointe Tematapu, Atelier RAPA Stn 34; 27°34’47”S, 144°19’1”W; 2-8 m; 19.XI.2002; slope in a large cave, muddy bottom; MNHN • 13 dd; Rapa , SE of Pointe Tematapu, Atelier RAPA Stn 35; 27°34’47”S, 144°19’1”W; 2 m; 20.XI.2002; pebbles at cave exit; MNHN • 92 dd; Rapa , SE of Pointe Tematapu, Atelier RAPA Stn 35; 27°34’47”S, 144°19’1”W; 2 m; 20.XI.2002; pebbles at cave exit; MNHN • 2 dd; Rapa , SE of Tauna I., Atelier RAPA Stn 8; 27°36’28”S, 144°17’41”W; 52-57 m; 06-22.XI.2002; rocky bottoms with sandy pockets; MNHN • 27 dd; Rapa , SW of Pointe Gotenaonao, Atelier RAPA Stn 27; 27°38’41”S, 144°19’11”W; 6 m; 14.XI.2002; pebble blocks with algae cover; MNHN • 33 dd; Rapa , SW of Pointe Gotenaonao, Atelier RAPA Stn 27; 27°38’41”S, 144°19’11”W; 6 m; 14.XI.2002; pebble blocks with algae cover; MNHN • 154 dd; Rapa , SW of Pointe Gotenaonao, Atelier RAPA Stn 27; 27°38’41”S, 144°19’11”W; 6 m; 14.XI.2002; pebble blocks with algae cover; MNHN • 5 dd; Rapa , SW of Rarapai I., Atelier RAPA Stn 17; 27°34’37”S, 144°22’40”W; 9 m; 10.XI.2002; rocky boulders on sandy bottom; MNHN • 87 dd; Rapa , SW of Rarapai I., Atelier RAPA Stn 17; 27°34’37”S, 144°22’40”W; 9 m; 10.XI.2002; rocky boulders on sandy bottom; MNHN • 5 dd; Rapa , Vavai, Atelier RAPA Stn 20; 27°35’23”S, 144°23’16”W; 5 m; 12.XI.2002; coral blocks on sand bottom; MNHN • 46 dd; Rapa , Vavai, Atelier RAPA Stn 20; 27°35’23”S, 144°23’16”W; 5 m; 12.XI.2002; coral blocks on sand bottom; MNHN • 53 dd; Rapa , Vavai, Atelier RAPA Stn 32; 27°34’58”S, 144°22’40”W; 15-20 m; 18.XI.2002; coral; MNHN • 3 dd; Rapa , W of Pointe Aukura, Atelier RAPA Stn 15; 27°38’6”S, 144°21’7”W; 20 m; 9.XI.2002; sandy pockets amidst large rocky blocks; MNHN • 14 dd; Rapa , W of Tauna I., Atelier RAPA Stn 16; 27°36’18”S, 144°18’25”W; 5 m; 9.XI.2002; corals, mostly dead; MNHN • 111 dd; Rapa , W of Tauna I., Atelier RAPA Stn 16; 27°36’18”S, 144°18’25”W; 5 m; 9.XI.2002; corals, mostly dead; MNHN • 1 dd; Rapa , wharf of Area, Atelier RAPA Stn 70; 27°36’35”S, 144°19’29”W; 15-20 m; 20.XI.2002; muddy pockets and corals; MNHN • 3 dd; Rapa , wharf of Area, Atelier RAPA Stn 70; 27°36’35”S, 144°19’29”W; 15-20 m; 20.XI.2002; muddy pockets and corals; MNHN • 1 dd; Banc Président Thiers, BENTHAUS Stn DW1933; 24°40’58”S, 146°1’1”W; 500-850 m; 14.XI.2002; MNHN • 1 dd; Banc Arago BENTHAUS Stn DW1974; 23°23’59”S, 150°43’58”W; 450-618 m; 20.XI.2002; MNHN • 1 dd; Banc Arago, BENTHAUS Stn DW1975; 23°23’59”S, 150°43’58”W; 600-691 m; 20.XI.2002; MNHN • 13 dd; S of Rurutu BENTHAUS Stn DW2010; 22°31’58”S, 151°20’59”W; 520-950 m; 24.XI.2002; MNHN • 9 dd; S of Rurutu , BENTHAUS Stn DW2010; 22°31’58”S, 151°20’59”W; 520-950 m; 24.XI.2002; MNHN • 8 dd; Rurutu , Toataratara,; 22°31’29”S, 151°20’38”W; beached; coll. MB • 27 dd; Rimatara, BENTHAUS Stn DW2020; 22°37’1”S, 152°49’1”W; 920-930 m; 25.XI.2002; MNHN • 73 dd; Rimatara, BENTHAUS Stn DW2021; 22°37’1”S, 152°49’1”W; 1200-1226 m; 25.XI.2002; MNHN • 18 dd; Maria Island ; 21°48’0”S, 154°40’58”W; 20 m; coll. JL .

Society Islands • 5 dd; Tahiti, Arue; 17°31’15”S, 149°31’33”W; <1m; reef flat (‘platier’) behind tomb of King Pomare V; coll. JL • 17 dd; Tahiti, Mahaena; 17°33’57”S, 149°19’22”W; <1 m; reef flat; coll. JL • 10 dd; Tahiti, Punaauia, La Source; 17°36’7”S, 149°37’15”W; 20 m; coll.JL • 1 dd;Tahiti, Papara lagoon; 17°45’28”S, 149°31’22”W; 1 m; coastal reef flat, in coarse sand; coll. MB • 1 dd; Tahiti, Toahotu lagoon; 17°45’32”S, 149°19’4”W; beached; beached sediment; coll. MB • 36 dd; Moorea; 17°33’57”S, 149°47’13”W; 1 m; lagoon; coll. JL.

Tuamotu • 5 dd; Moruroa; 21°46’37”S, 138°53’31”W; beached; on the sea-line; coll. MB.

DISTRIBUTION AND SYMPATRY. — The species is at present known in the South Pacific Ocean from the Australes (Marotiri, Rapa, Banc Président Thiers, Banc Arago, Rurutu, Rimatara, Maria), Society Islands (Tahiti, Moorea) and Tuamotu (Moruroa) ( Fig. 52A ).

Simulamerelina australes n. sp. is sympatric with S. densestriata n. sp. in the Australes (Marotiri); with S. micrometrica n. sp. in the Australes (Rapa, Banc Président Thiers, Banc Arago, Rurutu, Rimatara); with S. gracilis n. sp. in the Tuamotu (Moruroa) ( Table 9 ).

ETYMOLOGY. — The name is after the area of the type locality (Australes Islands) used as a noun in apposition.

DIAGNOSIS. — Simulamerelina with large size shell for the genus (> 2 mm), slender and robust. Protoconch paucispiral. Teleoconch with marked spiral and axial sculpture. Axial ribs reaching the base. Start of 2 spiral cordlets after protoconch-teleoconch boundary. Colouration uniform or with bands of darker colour.

DESCRIPTION OF HOLOTYPE

Shell ( Figs 36A ; 43 A-C; 53O)

Large for the genus, height 2.47 mm, width 1.12 mm height/ width ratio 2.21, turriculate-slender, elongate ovate.

Protoconch ( Fig. 36B )

Paucispiral with twisted nucleus, of 1.25 convex whorls, height 0.300 mm, nucleus diameter 0.100 mm, first half whorl diameter 0.225 mm, maximum diameter 0.305 mm. Sculpture of a keel on the upper fifth, and micro granules on the whole surface vaguely arranged in spiral bands. Protoconch-teleoconch boundary well marked.

Teleoconch

Of 4.5 convex whorls, suture impressed. Axial sculpture on the last whorl of 15 slightly prosocline ribs, slightly stronger than the spiral cordlets, and narrower than the interspaces, reaching the base. Spiral sculpture of strong non equidistant cordlets, 2 central on the first whorl, three on the next two whorls and 8 on the last whorl, of which 3 above the aperture, 1 on the suture line and 4 on the base. Cordlets II and III starting immediately after the protoconch-teleoconch boundary; cordlet I, subsutural, forming shortly after. Cordlet II located slightly closer to cordlet I. Slightly nodulose thickenings at intersections; interspaces quadrangular. Entire surface covered by dense regularly distributed spiral threads, both on the cordlets and on the interspaces ( Fig. 36C ). Umbilical fissure very narrow. Aperture oval height 0.83 mm, height/ aperture height ratio 2.98, peristome duplicated, internally smooth, externally thickened by a strong opisthocline varix.

Colour

Colouration uniform light brown, slightly darker before the varix; peristome whitish.

Operculum and soft parts

Operculum typical of the genus; soft parts unknown.

VARIABILITY

Variable in the height/width ratio (2.01-2.36) and in the outline, from cylindrical to pupoid. Minimum dimensions: adult height 1.67 mm (specimen from the Australes, East of Rapa 600-620 m) and maximum: 2.67 mm (specimen from the Australes, Rapavavai). Colour uniform brown-orange or white with whitish outer lip; frequently with two darker, subsutural and basal bands. Colour fading in old shells ( Fig. 35 ). (See Table 8 and Appendices 15; 16).

REMARKS

Simulamerelina granulosa ( Pease, 1862) , from Hawaii ( Pease 1862: 382, pl. 13, fig.10), differs from Simulamerelina australes n. sp. in the smaller size (2 mm vs> 2 mm in S. australes n. sp.); the outer lip with 5 short lirae internally (fide Kay 1979: 80), smooth internally in S. australes n. sp.; the axial ribs stopping on the third spiral cordlet, not reaching the base, vs reaching the base in S. australes n. sp.; the protoconch of 1.5 whorls, with a small and smooth first whorl, and spiral striae on the last part (fide Kay 1979: 80) vs 1.25-1.40 whorls with a keel on the adapical fifth, with micro granules vaguely arranged in spiral bands in S. australes n. sp.

Simulamerelina ferruginea (A. Adams, 1861) n. comb. from Hakodadi Bay ( Japan), 7 fathoms (A. Adams, 1861: 138) [synonym of Simulamerelina tokyoensis ( Pilsbry, 1904) ] differs from Simulamerelina australes n. sp. in the dome-shaped protoconch devoid of evident keel, vs sculptured by a keel on the adapical fifth, with microgranules vaguely arranged in spiral bands in S. australes n. sp.; the teleoconch sculpture of four spiral cordlets on the last whorl above the aperture vs three in S. australes n. sp.; the more rounded tubercles vs more protruding in S. australes n. sp.; the more prosocline outer lip. Alison Kay (‘ in schedis ’, on recent label ANSP 70910 of S. tokyoensis ), hypothesized a synonymy of S. tokyoensis (now S. ferruginea ) with S. granulosa . We consider them as distinct species, based on some shell characteristics. Pupoid profile in S. ferruginea vs cylindrical in S. granulosa and with lower height/width ratio (1.85-1.95 vs 2.16-2.88 in S. granulosa ); spiral sculpture on the last whorl in greater number 8-9 vs 5-7 in S. granulosa ; outer lip internally smooth vs with five short denticles in S. granulosa , and with a much more marked opisthocline inclination in S. ferruginea . Furthermore, the large geographical distance between the two species ( Japan vs Hawaii) for both species with non-planktotrophic development would support this specific separation.

Simulamerelina corruga ( Laseron, 1956) from Heron I., Capricorn Group (north-eastern Australia) ( Laseron 1956: 436, fig. 136), differs from Simulamerelina australes n. sp. in the protoconch sculptured with three smooth spiral keels, and minute granules in the interspaces vs a keel on the adapical fifth, with microgranules vaguely arranged in spiral bands in S. australes n. sp.

Simulamerelina didyma (R. B. Watson, 1886) from North of Culebra and St Thomas Islands, Virgin Islands, Western Atlantic (R. B. Watson 1886: 594, pl. 44, fig. 1) differs from Simulamerelina australes n. sp. in the dome-shaped protoconch devoid of spirals, with microtubercles vs sculptured with a keel on the adapical fifth, with microgranules vaguely arranged in spiral bands in S. australes n. sp.; the axial ribs stopping on the first basal cordlets, with smooth basal spiral cordlets vs more robust teleoconch sculpture with narrower interspaces and axial ribs reaching the base in S. australes n. sp.

Simulamerelina gemmata ( Powell, 1927) from Maro Tiri (Chicken Island, off North I., New Zealand) ( Powell 1927: 537, pl. 26, fig. 1), differs from S. australes n. sp. in the protoconch dome-shaped, of 1.5 whorls sculptured with three keels vs 1.25 convex whorls, sculptured by a single keel on the adapical fifth, with micro granules vaguely arranged in spiral bands in S. australes n. sp.; in the more acute tubercles at the intersection; in the fewer spiral cordlets on the last whorl [6 (3+1+2) vs 7-8 (3+1+3-4) S. australes n. sp.].

The most slender specimens with banded colouration of Simulamerelina australes n. sp. are very similar ( Fig. 34H ) to both Merelina elegans (Angas, 1877) and Merelina taupoensis Powell, 1939 ( Criscione & Ponder 2011: 72, figs 2A-E, 3C, 4C, 8A, B; Criscione et al. 2016: 9, fig. 5G; Images from malacology, at https://malacopics.nl/ Lironobidae /album/ slides/ Merelina %20elegans.html and https://malacopics.nl/ Lironobidae /album/slides/ Merelina %20taupoensis.html; accessed on 26 January 2023). We note that these two taxa may actually represent a single species, considering the very similar shells. However, they differ from Simulamerelina australes n. sp. in the deeper and more evident suture; the smaller and more rounded aperture; the protoconch with 11 ( M. elegans ) and 12 ( M. taupoensis ) spiral cordlets vs a single keel on the adapical fifth, with micro granules vaguely arranged in spiral bands in S. australes n. sp.

See under Simulamerelina densestriata n. sp. for detailed comparisons.

Figures

FIG. 34. — Simulamerelina australes n. sp.: A-C, holotype, Australes, Rapa, cave SE of Pointe Tematapu, Atelier RAPA Stn 34, 2-8 m, height 2.47 mm, MNHN- IM-2000-38722.

FIG. 35. — Simulamerelina australes n. sp.: variability of the species. Australes, E of Rapa, BENTHAUS Stn DW1889, 600-620 m: A, height 2.60 mm, MNHN; B, height 2.30 mm, MNHN; C, height 2.10 mm, MNHN; D, height 2.35 mm, MNHN; E, height 1.67 mm, MNHN; F, height 2.20 mm, MNHN; G, height 2.40 mm, MNHN; H, height 2.15 mm, MNHN.

FIG. 36. — Simulamerelina australes n. sp.: holotype, Australes,Rapa, cave SE of Pointe Tematapu, Atelier RAPA Stn 34, 2-8 m, height 2.47 mm, width 1.12 mm, MNHN-IM-2000-38722: A, shell; B, detail of the first whorls; C, detail of the microsculpture. Scale bars: B, 100 μm, C, 30 μm.

FIG. 37. — Simulamerelina australes n. sp.: Australes, E of Rapa, BENTHAUS Stn DW1889, 600-620 m, height 2.60 mm, width 1.15 mm, MNHN:A, shell; B, detail of the first whorls; C, detail of the microsculpture. Scale bars: B, 100 μm, C, 30 μm.

FIG. 52. — Distribution maps of the Polynesian species of Simulamerelina Ponder, 1985 and Subestea Cotton, 1944: A, Simulamerelina australes n. sp.; B, Simulamerelina densestriata n. sp. (○), Simulamerelina gracilis n. sp. (●), Simulamerelina lepteseiras n. sp. (✩); C, Simulamerelina micrometrica n. sp. (○), Simulamerelina tuamotu n. sp. (●); D, Subestea moruroa n. sp. (○).

FIG. 53. — Alvania Risso,1826,Ellenstrongia n. gen., Haurakia Iredale,1915,Parashiela Laseron,1956,Simulamerelina Ponder,1985 and Substea Cotton,1944:A, Alvania letouneuxi n.sp., holotype,MNHN-IM-2000 38703, height 1.60 mm; B, Alvania herosae n. sp., holotype,MNHN-IM-2000-38704, height 2.02 mm;C, Alvania herosae n.sp.(morph B),MNHN,height 2.16 mm;D, Alvania parvimaculata n. sp.,holotype,MNHN-IM-2000-38706, height 1.65 mm;E, Alvania prosocostata n.sp., holotype, MNHN-IM-2000-38708 height 2.05 mm; F, Alvania uapou n. sp., holotype, MNHN-IM-2000-38710, height 1.70 mm; G, Ellenstrongia tarasoc n. gen., n. sp., holotype,MNHN-IM-2000-39448, height 4.50 mm; H, Haurakia marmorata (Hedley, 1907), Society Islands,height 1.95 mm, coll. JL; I, Parashiela ambulata Laseron, 1956, Australes: Rapa Pointe Kauira, height 1.60 mm, MNHN; J, Parashiela expansilabrum n. sp. holotype, MNHN-IM-2000-38712 height 1.47 mm; K, Parashiela obesula n. sp. holotype, MNHN-IM-2000-38714, height 1.32 mm; L, Parashiela rimatara n. sp. holotype, MNHN-IM-2000-38716, height 1.47 mm; M, Parashiela rotundata n. sp. holotype, MNHN-IM-200038718-, height 1.10 mm; N, Parashiela soniae n. sp., holotype, MNHN-IM-2000-38720, height 1.17 mm; O, Simulamerelina australes n. sp. holotype, MNHN-IM-2000-38722, height 2.47 mm; P, Simulamerelina densestriata n. sp., holotype, MNHN-IM-2000-38724, height 2.45 mm; Q, Simulamerelina gracilis n. sp., holotype, MNHN-IM-2000-38726, height 2.45 mm; R, Simulamerelina lepteseiras n. sp., holotype, MNHN- IM-2000-38727, height 1.47 mm; S, Simulamerelina micrometrica n. sp., holotype, MNHN-IM-2000-38728, height 1.33 mm; T, Simulamerelina tuamotu n. sp. holotype, MNHN-IM-2000-38730, height 1.57 mm; U, Subestea moruroa n. sp., holotype, MNHN-IM-2000-38732, height 1.96 mm.

FIG. 38. — Simulamerelina densestriata n. sp.: A-C, holotype, Australes, Marotiri, BENTHAUS Stn DW1885; 700-800 m, height 2.45 mm, MNHN-IM-2000-38724; D, paratype, Australes, Marotiri, BENTHAUS Stn DW1885, 700-800 m, height 2.58 mm, MNHN-IM-2000-38725; E-G, paratype, Australes, Marotiri, BENTHAUS Stn DW1885, 700-800 m, height 2.35 mm, detail of the first whorls (G), MNHN-IM-2000-38725. Scale bars: G, 25 μm.

FIG. 39. — Simulamerelina densestriata n. sp.: holotype, Australes, Marotiri, BENTHAUS Stn DW1885, 700-800 m, height 2.45 mm, MNHN-IM-2000-38724: A, shell; B, detail of the first whorls; C, detail of the microsculpture between the first and second whorl. Scale bars: B, C, 100 μm.

FIG. 40. — Simulamerelina gracilis n. sp.: A-C, G-I, holotype, Tuamotu, Moruroa, on the sea line, height 2.45 mm, width 1.08 mm, MNHN-IM-2000-38726; D-F, paratype,same data and locality of the holotype, height 2.13 mm, width 0.98 mm, shell (D), detail of the protoconch (E, F), shell (G), detail of the protoconch (H), detail of the microsculpture of the teleoconch (I); coll. MB. Scale bars: E, F, 20 μm H, 100 μm, I, 30 μm.

FIG. 41. — Simulamerelina lepteseiras n. sp., holotype, Tuamotu. Moruroa, beached, height 1.47 mm, width 0.88 mm, MNHN-IM-2000-38727: A-C, F, shell; E, G, detail of the protoconch; H, detail of the microsculpture of the teleoconch. Scale bars: E, H, 40 μm, D, G, 100 μm.

FIG. 42. — Simulamerelina micrometrica n.sp.:A-C, holotype height 1.33 mm Australes,East of Rapa,BENTHAUS Stn DW1889;600-620 m, MNHN-IM-2000-38728; D, height 1.46 mm,Australes,Banc Président Thiers,BENTHAUS Stn DW1926;50-90 m, MNHN;E, height 1.16 mm,Australes,Banc Président Thiers,BENTHAUS Stn DW1933; 500-850 m, MNHN;F-H, paratype height 1.46 mm, same locality and data as holotype,MNHN-IM-2000-38729; I, height 1.13 mm, Australes,Banc Président Thiers, BENTHAUS Stn DW1926; 50–-90 m, MNHN; J, height 1.2 mm, Australes, Banc Président Thiers, BENTHAUS Stn DW1926; 50-90 m, MNHN; K, height 1.36 mm, Australes, Banc Arago, BENTHAUS Stn DW1978; 120-180 m, MNHN; L, height 1.43 mm, Australes, Banc Président Thiers, BENTHAUS Stn DW1933; 500-850 m, MNHN; M, height 1.51 mm, Australes, Rimatara, BENTHAUS Stn DW2020; 920-930 m, MNHN; N, height 1.53 mm, Australes, North of Raivavae, BENTHAUS Stn DW1943; 950 m, MNHN; O, height 1.55 mm, Australes, Rimatara, BENTHAUS Stn DW2021; 1200-1226 m, MNHN.

FIG. 43. — Simulamerelina micrometrica n. sp.:A-C, holotype height 1.33 mm Australes,East of Rapa,BENTHAUS Stn DW1889;600-620 m,MNHN-IM-2000-38728; D-F, paratype, height 1.46 mm same locality and data as holotype, MNHN-IM-2000-38729. Scale bars: B, E, 100 μm, C, 200 μm, F, 40 μm.

FIG. 44. — Simulamerelina tuamotu n. sp.: A-C, holotype, Tuamotu, Makemo, Nake, <1 m, height 1.57 mm, width 0.90 mm, MNHN-IM-2000-38730; D, paratype, Tuamotu,Makemo, Nake, <1 m, height 1.58 mm, MNHN-IM-2000-38731; E, paratype, Tuamotu, Makemo,Nake, <1 m, height 1.27 mm, MNHN-IM-2000-38731.

FIG. 45. — Simulamerelina tuamotu n. sp.: holotype, Tuamotu, Makemo, Nake, <1 m, MNHN-IM-2000-38730: A, shell, height 1.57 mm, width 0.90 mm; B, detail of the first whorls; C, detail of the microsculpture of the second whorl (MNHN-IM-2000-38730). Scale bars: B, 100 μm, C, 30 μm.