Benthonellania lozoueti, Amati & Giulio & Oliverio, 2022

Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2022, Deep-water Rissoidae of the genera Benthonella Dall, 1889 and Benthonellania Lozouet, 1990 (Gastropoda, Caenogastropoda, Rissooidea) from French Polynesia, Zoosystema 44 (12), pp. 335-389 : 370-373

Benthonellania lozoueti n. sp.

( Figs 21 ; 22 E-I; 25F; 26N; Tables 1 ; 2)

urn:lsid:zoobank.org:act:3D02DD07-801C-4BE4-ABE3-F5D4FF4EAD2F

TYPE MATERIAL. — Holotype. Marquesas • 1 dd (height 4.33 mm, width 2.66 mm, Figs 21 A-C, 22E-I); Fatu Hiva , MUSORSTOM 9 Stn DR1244 ; 10°28’S, 138°42’W; 1.IX.1997; 1015-1020 m depth; MNHN-IM-2000-37701

Paratypes • 10 dd; same locality data as holotype • 6 dd; MNHN- IM-2000-37703; Fatu Hiva, Stn DR 1247; 10°34’S, 138°42’W; 1.IX.1997; 1150-1250 m depth; MNHN-IM-2000-37702 .

OTHER MATERIAL EXAMINED. — Marquesas • 3 dd; Eiao, MUSORSTOM 9 Stn CP 1278; 7°52’S, 140°39’W; 5.IX.1997; 1000 m depth; MNHN • 1 dd; Eiao, MUSORSTOM 9 Stn DW 1275; 7°53’S, 140°38’W; 5.IX.1997; 627 m depth; MNHN .

TYPE LOCALITY. — Marquesas, Fatu Hiva, MUSORSTOM 9 Stn DR1244; 10°28’S, 138°42’W; 1.IX.1997; 1015-1020 m depth.

DISTRIBUTION AND SYMPATRY. — The species is at present known from the South Pacific Ocean, at Marquesas (Eiao Island and Fatu Hiva Island), with only empty shells collected in 627-1250 m depth ( Fig. 25F ).

Benthonellania lozoueti n. sp. is sympatric with Benthonella boucheti n. sp. at the Marquesas (Fatu Hiva Island); with Benthonellania megan n. sp. at the Marquesas (Fatu Hiva Island) ( Table 2).

ETYMOLOGY. — This species is named after Pierre Lozouet (MNHN, Paris) for his contribution to Malacology, including his work on Benthonella and Benthonellania .

DESCRIPTION OF HOLOTYPE

Shell ( Figs 21 A-C; 22E-I)

Large for the genus, height 3.86 mm, width 2.6 mm, height/ width ratio 1.484, pretty solid, ovate-conical.

Protoconch ( Fig. 22 F-H)

Multispiral, of 2 whorls, height 0.35 mm, nucleus diameter 0.10 mm, first half whorl diameter 0.175 mm, maximum diameter 0.412 mm; protoconch I with only microtubercles, some spirally arranged ( Fig. 22G ), protoconch II with three zig-zag spiral cordlets on upper part; inferiorly a fourth spiral cord. In the second half of the whorl, numerous microstructures often welded between them ( Fig. 22F, H ). Protoconchteleoconch boundary barely visible.

Teleoconch

Of 4 convex whorls, suture canaliculate, crowned by small tubercles at tips of axial ribs, highlighted by a subsutural spiral groove. Height last whorl 2.8 mm. height/height last whorl ratio 1.378. Axial sculpture of 26 curved and opisthocline ribs on last whorl, narrower than interspaces, gradually vanishing towards the base. Spiral sculpture of 7 (last one barely visible) weak fine cordlets on the base, uppermost one, suprasutural, visible on all whorls. Weak bulges at intersections with axial ribs. Microsculpture of only growth striae ( Fig. 22I ). Umbilical chink present. Aperture pyriform, large, height 1.75 mm, height/height aperture ratio 2.205, peristome continuous, outer lip broken. Columella arcuate, simple.

Colour

Coloration of teleoconch translucent white, protoconch whitish.

Operculum and soft parts

Unknown.

VARIABILITY

Species not very variable (See Table 1 and Appendix 13).

REMARKS

All the examined specimens have a broken peristome (presence/absence of lip thickening not observable).

B. lozoueti n. sp. differs from B. tuamotu n. sp. by the presence of weak thickenings at the intersections of the spiral cordlets with the axial ribs, absent in B. tuamotu n. sp.; B. lozoueti n. sp. has a slightly convex base vs slightly concave in B. tuamotu n. sp. and on average has more numerous and finer axial ribs (22.4 vs 17.5 in B. tuamotu n. sp.).

Figures

FIG. 21. — Benthonellania lozoueti n. sp.: A-C, holotype, height 3.86 mm, width 2.6 mm, Marquesas: MUSORSTOM 9 Stn DR1244, 1015-1020 m, 10°28’S, 138°42’W, MNHN-IM-2000-37701; D-G, paratype,height 4.33 mm, width 2.66 mm, type locality, MNHN-IM-2000-37702; H-J, specimen, height 3.55 mm, width 2.3 mm, Marquesas: MUSORSTOM 9 Stn CP1278, 1000 m, 7°52’S, 140°39’W. Scale bar: G, 0.50 mm.

FIG. 22. — Benthonellania spp. (SEM): A-D, Benthonellania tuamotu n. sp., holotype, MNHN-IM-2000-37697, Tuamotu: height 4.42 mm: shell (A), detail of the protoconch microsculture (B, D); detail of the teleoconch axial sculture (C); E-I, Benthonellania lozoueti n. sp., holotype, MNHN-IM-2000-3770, Marquesas:height 3.86 mm:shell (E), detail of the protoconch microsculture (F-H), detail of the teleoconch axial sculture (I). Scale bars:B, H, 50 μm;C, D, I, 100 μm;F,30 μm;G,20 μm.

FIG. 25. — Distribution maps of the Polynesian species of Benthonella Dall,1889 and Benthonellania Lozouet,1990: A, Benthonella boucheti n. sp.;B, Benthonella basistriata n. sp.; C, Benthonella communis n. sp.; D, Benthonellania bouteti n. sp.; E, Benthonellania alis n. sp.; F, Benthonellania tarava n. sp. (◯) and Benthonellania lozoueti n. sp. (); G, Benthonellania megan n. sp. (◯) and Benthonellania maestratii n. sp. (); H, Benthonellania tuamotu n. sp.