Alvania uapou Amati & Giulio & Oliverio 2023, n. sp.
Creators: name: Amati, Bruno
name: Giulio, Andrea Di
name: Oliverio, Marco
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Rissoidae
Alvania
Alvania uapou

description: Alvania uapou n. sp.
(Figs 18A, B; 19; 49C; 53F; Tables 1; 2)
urn:lsid:zoobank.org:act: 7CCE5B97-5F67-406C-B57B-14C3C31F84F8
Alvania isolata – Tröndlé & Boutet 2009: 17. — Salvat & Tröndlé 2017: 238.
Alvania sp. 1 – Boutet et al. 2020: 239.
TYPE MATERIAL. — Holotype. Marquesas • lv (height 1.70 mm, width 0.90 mm); Ua Pou, Motu Mokohe, Atelier MARQUISES Stn 20; 9°20’49”S, 140°5’45”W; 10-15 m; 26.X.1999; Bryce & Kaiser leg.; MNHN-IM-2000-38710.
Paratypes. Marquesas • 17 dd, 24 lv (Fig. 18 C-F); same locality data as holotype; MNHN-IM-2000-38711.
TYPE LOCALITY. — Marquesas: Ua Pou, Motu Mokohe, Atelier MARQUISES Stn 20; 9°20’49”S, 140°5’45”W; 10- 15 m.
OTHER MATERIAL EXAMINED. — Marquesas • 5 dd, 4 lv; Fatu Hiva, Matautu cave, PAKAIHI I TE MOANA Stn MQ 15-GR; 10°28’19”S, 138°40’40”W; 0-28 m; 17-18.I.2012; MNHN • 4 dd; Fatu Hiva, MUSORSTOM 9 Stn DR1247; 10°34’1”S, 138°41’59”W; 1150- 1250 m; 1.IX.1997; MNHN • 5 dd; Tahuata; 9°54’0”S, 139°7’1”W; 48 m; 31.VIII.1990; MNHN • 2 lv; Tahuata, PAKAIHI I TE MOANA Stn MQ12-M (intertidal); 9°58’12”S, 139°7’33”W; 0-1 m; 15.I.2012; MNHN • 3 dd; Hiva Oa, MUSORSTOM 9 Stn DR1200; 9°49’55”S, 139°8’52”W; 96-100 m; 28.VIII.1997; MNHN • 21 dd; Hiva Oa; 9°45’46”S, 138°52’33”W; <1 m; in coarse sand near the shore; coll. MB • 14 dd; Hiva Oa, MUSORSTOM 9 Stn DW1206; 9°50’59”S, 139°9’0”W; 352-358 m; 28.VIII.1997; MNHN • 1 dd, 7 lv; NE Hiva Oa, PAKAIHI I TE MOANA Stn MQ19-B; 9°45’39”S, 138°50’41”W; 10-25 m; 21.I.2012; cave exit; MNHN • 99 lv; NE Hiva Oa, PAKAIHI I TE MOANA Stn MQ19-B; 9°45’39”S, 138°50’41”W; 10-25 m; 21.I.2012; cave exit; MNHN • 82 dd, 9 lv; Ua Pou, Hatu Iti, cave, PAKAIHI I TE MOANA Stn MQ27-GR; 9°23’41”S, 140°7’44”W; 5-22 m; 25.I.2012; MNHN • 4 dd; Ua Pou, Haakuti, Vaietu Bay (Cape Punatu); 9°23’9”S, 140°7’47”W; 68 m; coll. JL • 4 dd; Ua Pou, Hakahetau Bay; 9°21’28”S, 140°6’14”W; 1-3 m; coll. JL • 9 dd; Ua Pou, Hakaheteau cave, PAKAIHI I TE MOANA Stn MQ21- GR; 9°22’8”S, 140°6’50”W; 6-10 m; 23.I.2012; MNHN • 2 dd; Ua Pou, Hakaomaka, Atelier MARQUISES Stn 19; 9°20’49”S, 140°5’49”W; 10-20 m; 25.X.1999; Bryce & Kaiser leg.; MNHN • 2 dd; Ua Huka, Hiniaehi Bay-Hinitaihava Bay, Atelier MARQUISES Stn 12; 8°55’58”S, 139°32’49”W; intertidal; IX.1997; ‘trottoir’ with sandy pockets, Bryce & Kaiser leg.; MNHN • 2 dd; Ua Huka, MUSORSTOM 9 Stn DW1288; 8°54’0”S, 139°37’58”W; 200-220 m; 8.IX.1997; MNHN • 4 dd, 1 lv; Nuku Hiva Talohae Bay, W Moto Nui; 8°56’9”S, 140°6’39”W; 10-20 m; 18.X.1999; Scuba dead coral, loose rocks on slope; MNHN • 3 dd; Nuku Hiva, Anao Bay; 8°49’40”S, 140°3’32”W; beached; coll. MB • 58 lv; Nuku Hiva, Ekamako cave, PAKAIHI I TE MOANA Stn MQ1-GR; 8°56’13”S, 140°5’27”W; 8-10 m; 07, 28.I.2012; MNHN • 11 dd, 5 lv; Nuku Hiva, Les 4 grottes, PAKAIHI I TE MOANA Stn MQ2-GR; 8°56’13”S, 140°7’15”W; 20-23 m; 07, 11-13, 29.I.2012; MNHN • 53 dd, 2 lv; Nuku Hiva, Matateteiko, PAKAIHI I TE MOANA Stn MQ3-GR; 8°55’58”S, 140°13’33”W; 20-25 m; 8.I.2012; MNHN • 34 dd; Nuku Hiva, MUSORSTOM 9 Stn DW1184; 8°49’19”S, 140°3’36”W; 23-30 m; 26.VIII.1997; MNHN • 19 dd; Nuku Hiva, Taiohae Bay, W Matauapuna, Atelier MARQUISES Stn 02; 8°56’13”S, 140°5’41”W; 10-20 m; 18.X.1999; Bryce & Kaiser leg.; MNHN • 5 lv; Hatutu, Cave, PAKAIHI I TE MOANA Stn MQ32-GR; 7°54’25”S, 140°33’57”W; 17-22 m; 27.I.2012; MNHN.
Australes • 1 dd; Rapa, Hiri Bay; 27°37’19”S, 144°22’4”W; 3-5 m; coll. JL.
Society Islands • 22 dd; Tahiti, Arue, Matavai Bay; 17°31’15”S, 149°31’33”W; 1-16 m; behind the King’s tomb; coll. JL • 1 dd; Tahiti, Faille d’Arue; 17°31’1”S, 149°31’30”W; 18 m; in sediment of the outer slope; coll. MB • 15 dd; Tahiti, Faille d’Arue; 17°31’1”S, 149°31’30”W; 15-48 m; coll. JL • 15 dd; Tahiti, Motu Uta; 17°31’51”S, 149°34’51”W; 20 m; wreck, behind breakwater; coll. JL • 4 dd; Tahiti, Port Phaeton, Taravao isthmus; 17°43’19”S, 149°18’10”W; beached; in the sand of the beach; coll. MB • 25 dd; Tahiti, Punaauia, La Source; 17°36’7”S, 149°37’15”W; 30 m; coll. JL • 5 dd; Tahiti, Tiarei; 17°32’34”S, 149°20’27”W; <1 m; fringing reef flat; coll. JL.
DISTRIBUTION AND SYMPATRY. — Alvania uapou n. sp. is at present known in the South Pacific Ocean from the Marquesas (Fatu Hiva, Tahuata, Hiva Oa, Ne Hiva, Ua Pou, Ua Huka, Nuku Hiva, Hatutu), and from the Australes (Rapa) and the Society (Tahiti) (Fig. 49C), with 216 specimens live collected in 0-28 m depth, and 383 empty shells collected in 0-1250 m depth.
Alvania uapou n. sp. is sympatric with Alvania herosae n. sp. in the Australes (Rapa, Tubuai, Rurutu, Rimatara); with Alvania prosocostata n. sp. in the Australes (Rapa); with Alvania parvimaculata n. sp. in the Society (Tahiti) (Table 2).
ETYMOLOGY. — The species is named after the type locality, Ua Pou (Marquesas), used as a noun in apposition.
DIAGNOSIS. — Alvania with small (height <2 mm), slender and rather robust shell; paucispiral protoconch; teleoconch with orthocline axial ribs and spiral cordlets; 3 spiral cordlet starting immediately after the protoconch-teleoconch boundary; colouration translucent whitish-yellowish, with quadrangular subsutural brown blotches.
DESCRIPTION OF HOLOTYPE
Shell (Figs 18A, B; 19A; 53F)
Small for the genus, height 1.70 mm, width 0.90 mm, height/ width ratio 1.89, rather robust, ovate-conical.
Protoconch (Fig. 19B, C)
Paucispiral, dome-shaped, of 1.4 whorls, height 0.25 mm, nucleus diameter 0.100 mm, first half whorl diameter 0.175 mm, maximum diameter 0.287 mm; sculptured with seven zig-zag spiral threads (Fig. 19B, C). Protoconch-teleoconch boundary scarcely marked.
Teleoconch
Of 3.5 convex whorls, with suture impressed. Axial sculpture on last whorl of 14 orthocline ribs (plus the labial varix), narrower than a third of the interspaces, gradually vanishing at the base. Spiral sculpture of 9 not equidistant cordlets on last whorl of same size as axial ribs: 4 above the aperture, 1 on the suture line and 4 smooth on the base; 4 on the penultimate whorl. Cordlets II, III and IV starting immediately after the protoconch-teleoconch boundary; cordlet I, starting slightly later, thinner. Small, rounded tubercles at the intersections of the sculptures; interspaces quadrangular. Microsculpture of only fine growth striae (Fig. 19D, E). Umbilical fissure absent. Aperture piriform, height 0.60 mm, height/aperture height ratio 2.83, peristome continuous, outer lip with moderately thickened varix, internally smooth, sligthly prosocline.
Colour
Colouration translucent whitish-yellowish, with quadrangular subsutural brown blotches and other smaller basal ones; varix white, with a brown blotch just behind the varix.
Operculum and soft parts
Operculum typical for the genus: 0.300 mm width, 0.500 mm height in a specimen 1.5 mm high from NE Hiva Oa (PAKAIHI I TE MOANA Stn MQ19-B, MNHN). Soft parts unknown.
VARIABILITY
The examined materials (599 shell) showed negligible morphological variation. Height ranged in the examined material 1.2-2.0 mm (largest and smallest specimens, both from Marquesas). The presence of a fifth basal cord is quite rare and when present, it is always the thinnest. The interspace between spiral cordlets I and II is broader than the others. In some fresh specimens, a sharp labial regrowth is observed after the varix. The specimens from the Marquesas compared to those from the Society have smaller protoconchs and fewer axial ribs on the last teleoconch whorl (see Appendix 6). One specimen (coll. MB) from Tahiti (Society) is darker in colour, orange-brown with darker subsutural spots and has a fifth thin spiral cordlet above the aperture. The specimens of the Society Islands have spiral cordlets thinner than axial ribs. (See Table 1 and Appendix 6).
REMARKS
Alvania uapou n. sp. is similar to Alvania isolata (Laseron, 1956) described from Christmas Island (Indian Ocean) (Laseron 1956: 439, 479, fig. 144) (Fig. 4 A-H), with which it has been confused (e.g. Tröndlé & Boutet 2009; Salvat & Tröndlé 2017). Alvania isolata differs from Alvania uapou n. sp. by the order of appearance of the teleoconch spiral cordlets (II and IV first, then I and III vs II, III and IV first, then I at 0.20-1 whorl in Alvania uapou n. sp.); by the protoconch sculptured of 4-5 spiral cordlets vs thinner zig-zag cordlets In A. uapou n. sp.; by the colouration, whitish with small subsutural and basal speckles vs translucent whitish-yellowish, with quadrangular subsutural brown blotches and other smaller basal ones in Alvania uapou n. sp.
Alvania lavaleyei Hoenselaar & Goud, 1998 from Cape Verde Islands (Atlantic Ocean) (Hoenselaar & Goud 1998: 89, figs 41-43), broadly recalls A. uapou n. sp. It differs in the 6 zig-zag cordlets on the protoconch vs 7 fine zig-zag cordlets in A. uapou n. sp.; the colouration dirty-white to cream vs translucent whitish-yellowish, with quadrangular subsutural brown blotches and other smaller basal ones in A. uapou n. sp.; the spiral sculpture starting with 2 spiral cordlets vs 3 in A. uapou n. sp., and the 5 spiral cordlets on the last whorl above the aperture vs 4 in A. uapou n. sp.
Alvania awa Chinzei, 1959 [not Mimoto & Nakao 2013: 52, figs 2, 4] from the Japanese Pliocene (Chinzei 1959: 109: pl. 10, figs 1-4; holotype figured also in Hasegawa 2014: 138, figs 48 A-C), is probably a fossil-only species. Rare Recent specimens with similar features have been compared with the type material (Hasegawa 2014), but given the scarcity of specimens their conspecificity is still to be confirmed. However, both fossil and extant specimens referred to A. awa differ from A. uapou n. sp. in having only 3 spiral cordlets above the aperture vs 4 cordlets in A. uapou n. sp. in the lower and less convex protoconch; and in the more markedly prosocline inclination of the aperture. Moreover, in the two extant specimens (Hasegawa 2014: 138, figs 48D, E) from off Sado Island, 200-300 m, the H/W ratio is markedly lower 1.45-1.46 respectively vs 1.65-1.98 in A. uapou n. sp.
Alvania uapou n. sp. closely resembles the drawing and, in part, also the original description of Rissoa (Alvania) sombrerensis Thiele, 1925 (currently Alvania sombrerensis) from the Sombrero-Kanal (Indian Ocean, 7°48.8’N, 93°7.6’E, 805 m: Thiele 1925: 86, pl. 6, fig. 37). Alvania sombrerensis differs in the linear spiral sculpture of the protoconch vs zigzag sculpture in A. uapou n. sp., and in the fewer spiral cords on the last whorl (7 vs 8-9 in A. uapou n. sp.).
Alvania uapou n. sp. shares the peculiar zigzag pattern on the protoconch with several rissoid species, like e.g., the northeastern Atlantic Alvania vermaasi van Aartsen, 1975 and Alvania zylensis Gofas & Warén, 1982 (Hasegawa 2014: 132, 2022: 87; Oliver & Rolán 2017: 52), and particularly with Alvania jeffreysi (Waller, 1864), described from off Unst, Scotland, in 146-155 m (Waller 1864: 136), which differs in its larger size (height> 2 mm vs 1.2-2.0 mm A. uapou n. sp.); in the predominant spiral sculpture vs equally strong axials and spirals in A. uapou n. sp.; in the non-zigzag cordlets in the protoconch nucleus, changing to zigzag only in the last protoconch whorl vs zigzag cordlets in the whole protoconch starting from the nucleus in A. uapou n. sp.; in the uniform whitish-yellowish colouration vs translucent whitish-yellowish, with quadrangular subsutural brown blotches and white varix in A. uapou n. sp.
description: Published as part of 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, pp. 803-892 in Zoosystema 45 (25) on pages 824-827, DOI: 10.5252/zoosystema2023v45a25, http://zenodo.org/record/10458066