taxonID	type	description	language	source
E518B10EDA09C449FF11FEC7FA029E2E.taxon	description	Clade A, Williams et al., 2013 Type species: Arxellia trochos n. sp. — Recent, New Caledonia.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA09C449FF11FEC7FA029E2E.taxon	diagnosis	Diagnosis. Shell small to moderate (height up to 11.8 mm, width up to 13.0 mm), more or less conical in shape, spire moderate to high. Protoconch diameter 300 – 350 µm, with up to 6 thin spiral threads (in one species only abapical threads visible) and a thin, straight terminal lip without varix. Early teleoconch whorls usually with 5 or 6 beaded spiral cords of equal strength; adapical cord P 1 rapidly strengthening and becoming beaded; one abapical primary cord (P 5 or P 4 according to species) forming a low suprasutural carina starting from third whorl; carina may weaken or disappear on last whorl. Peristome incomplete; columella thickened in some species, with callus lobes at base and mid-point; granular deposition of calcium carbonate occurs where columella is thickened. Base convex to almost flat, with beaded cords on whole surface or with an intermediate smooth area, but always with at least one strong beaded spiral cord bordering umbilicus. Umbilicus open, narrow to moderately wide. The pink, green and opalescent shell colour of most species is larely due to a nacreous shell layer, rather than pigment. However, in some species shells do appear to be pigmented (e. g. the brown colour in A. boucheti, A. herosae, A. helicoides, A. maestrati and A. erythrea). Radula of type species with well-developed latero-marginal plates; formula (5 – 6) + 1 + 4 + 1 + 4 + 1 + (5 – 6). External anatomy typical of family; eyes pigmented (where known; see Williams et al. 2013); left neck lobe in the form of two short, non-papillate tentacles, the right one a trigonal lobe just behind eye-stalk; three papillate epipodial tentacles of more or less equal size present on each side, and additional smaller tentacle-like projection between the anterior pair on both sides. Operculum corneous, straw-brown, shallowly concave, multispiral with central nucleus; growing margin short.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA09C449FF11FEC7FA029E2E.taxon	discussion	Remarks. Diagnosis of the new genus is based on the nine species discussed herein. Live specimens collected at 242 – 650 m. Discussion. The new genus Arxellia corresponds to " Clade A " in the recent molecular phylogeny of the Solariellidae published by Williams et al. (2013). Seven of the new species and many of the specimens photographed were included in that study. The type species was not included, but unpublished molecular data confirm that it belongs in this clade (Williams, unpub. data). Genetic studies place Arxellia as the sister taxon to Archiminolia Iredale, 1929 with strong support. The two genera can be separated by shell shape (Archiminolia species have turban-shaped shells whereas Arxellia species have conical shells) and by the ontogeny of teleoconch spiral cords. In Arxellia there are numerous beaded spiral cords and a suprasutural carina on the intermediate whorls, whereas in Archiminolia there are at most a few subsutural cords on these whorls.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA09C449FF11FEC7FA029E2E.taxon	etymology	Etymology. Stronghold, citadel (Latin: arx) — referring to the strong columella of some species of the new genus (feminine). FIGURE 10: Approximate locations of MNHN and WAM expeditions discussed in this paper: ★: PANGLAO 2005; DZ: BIOPAPUA; D MUSORSTOM 8, VOLSMAR; ⊙: BORDAU 1; r: BORDAU 2; ♠: BIOCAL, MUSORSTOM 6, VOLSMAR, SMIB 8, BATHUS 1, BATHUS 2, LITHIST, NORFOLK 1, NORFOLK 2, EXBODI; DZ: CHALCAL 2, SMIB 8; ®: MUSORSTOM 7; + ' Southern Surveyor'.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA0CC445FF11FAAFFB5C9800.taxon	materials_examined	Type material. Holotype (5.9 x 5.3 mm) MNHN IM- 2009 - 23092. Paratypes: 3 MNHN IM- 2009 - 23109, IM- 2009 - 23094, IM- 2009 - 23089, 1 NHMUK 20140006. Type locality. New Caledonia, Banc de l’Orne / Walope, EXBODI, stn DW 3862, 22 ° 20 ' S, 169 ° 01 ’ E, 400 – 520 m. Material examined. South-western New Caledonia. BIOCAL: stn DW 08. 20 ° 34 ' S. 166 ° 54 ' E. 435 m. 16 dd. 8 dd sub. 8 dd juv. — Stn DW 83. 20 ° 35 ' S. 166 ° 54 ' E. 460 m. 4 dd. 1 dd juv. — BATHUS 2: stn DW 730, 23 ° 03 ' S, 168 ° 58 ' E, 397 – 400 m, 2 dd (one exceptionally large: 6 whorls, 8.4 x 7.0 mm). — EXBODI: stn CP 3851, 22 ° 19 ' S, 168 ° 45 ’ E, 471 – 510 m, 1 lv (paratype MNHN IM- 2009 - 23109). — Stn DW 3861, 22 ° 19 ' S, 169 ° 01 ’ E, 425 – 490 m, 1 lv (paratype MNHN IM- 2009 - 23094). — Stn DW 3862, 22 ° 20 ' S, 169 ° 01 ’ E, 400 – 520 m, 3 lv (holotype, paratypes MNHN IM- 2009 - 23089 and NHMUK 20140006). Loyalty Islands. MUSORSTOM 6: stn DW 410, 20 ° 38 ' S, 167 ° 07 ' E, 490 m. 3 dd. — Stn DW 413, 20 ° 40 ' S, 167 ° 03 ' E, 463 m. 1 dd. Fiji. BORDAU 1: stn DW 1486, 19 ° 01 ' S, 178 ° 26 ' W, 395 – 540 m, 34 dd, 16 dd juv. — Stn DW 1492, 18 ° 43 ' S, 178 ° 23 ' W, 430 – 450 m, 4 dd, 1 dd juv. — Stn DW 1496, 18 ° 43 ' S, 178 ° 23 ' W, 392 – 407 m, 4 dd.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA0CC445FF11FAAFFB5C9800.taxon	distribution	Distribution. South-western New Caledonia, 400 – 471 m (living at 471 – 490 m); Loyalty Islands, 463 – 490 m (dead); Fiji, 407 – 430 m (dead).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA0CC445FF11FAAFFB5C9800.taxon	description	Description. Shell: Size moderate for genus (height up to 6.8 mm, width up to 6.7 mm), conical, slightly higher than wide; height 1.0 – 1.1 x width, 3.1 – 3.5 x aperture height; periphery subangular. Protoconch paucispiral, diameter approx. 300 µm, rounded, with 5 thin, unequally spaced spiral threads; terminal lip straight, without varix. Teleoconch of up to 5.5 whorls; first two whorls convex, subsequent whorls almost straight-sided; shoulder oblique with angulate rim, except on last whorl where shoulder horizontal; whorls with 8 – 10 spiral cords; cords thin and nearly smooth on first two whorls, thicker and beaded on subsequent whorls, beads of adapical cords much stronger, intervals between cords narrower than width of cords. Suture canaliculate on early whorls, not so on final whorl. First whorl sculptured by 6 thin, more or less equally spaced, spiral cords; cords arising immediately after protoconch; P 1 at rim of shoulder; P 6 sometimes partially covered by suture; faint, close-set axial threads between cords. On second whorl, P 1 rapidly becoming stronger than other cords; P 3 and P 4 faint, difficult to distinguish; P 2 and P 5 of intermediate strength; axial threads evanescing by middle of whorl. Prosocline axial folds develop at start of third whorl, stronger on subsutural area and adapical part, rendering P 1 and P 2 subgranular; P 1 and P 5 the strongest cords, P 5 stronger than P 1, smooth, producing suprasutural (peripheral) carina; P 6 totally covered by suture; secondary cord S 3 arising at end of whorl, soon attaining size of P 3 and P 4. On fourth whorl, P 1 and P 2 strongly beaded, other cords subgranular; P 6 partially visible on some samples, weakly subgranular. On fifth whorl, T 1 arising at beginning of whorl, between suture and P 1; shoulder more or less horizontal, suture not canaliculate; axial folds much weaker, but still visible. On final whorl, P 6 arising at periphery; T 2 arising above P 5, rapidly resembling P 4; T 3 arising later between P 1 and P 2, beaded. Aperture subcircular; peristome incomplete; edge of outer and inner lips somewhat thickened; columella vertical, weakly concave, its edge slightly reflected at mid-point and overlapping umbilicus, a small flange at its base. Base weakly convex, almost flat, with 9 – 10 spiral cords; 3 – 4 outer cords smooth, relatively strong, their intervals similar to width of cords; cords of median area much weaker, their intervals approx. 1.5 x width of cords; 2 – 3 inner cords much stronger and beaded; innermost cord at rim of umbilicus, twice as wide as penultimate cord and with strong, axially elongate beads. Umbilicus deep, comparatively wide (diameter ca. 17 – 21 % of shell width), with angulate rim; internal wall almost straight, with 3 – 5 equally spaced, spiral cords of varying strength, crossed by axial grooves; intervals between cords approx. 0.5 – 1.0 x width of cords. Colour: Teleoconch whorls nacreous, white to greyish-blue, varying between samples; early teleoconch whorls white to deep grey, later whorls and base white to greyish-blue; protoconch white. Radula (Figs 23, 24): Rhipidoglossate; formula (5 – 6) + 1 + 4 + 1 + 4 + 1 + (5 – 6), with approx. 30 transverse rows of teeth; rows broadly M-shaped; rachidian cusp trigonal, with finely denticulate lateral margins and a somewhat larger central denticle; two inner lateral teeth similar to rachidian, but asymmetrical, their inner margin straight, the outer one curved; third lateral tooth more slender, fourth lateral tooth elongate and curved, with finer, more irregular denticles; interaction of base-plates complex; a well-developed, elongate-rectangular latero-marginal plate present; marginals 5 – 6, sickle-shaped, gradually tapering to a sharp point, lacking side denticles.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA0CC445FF11FAAFFB5C9800.taxon	discussion	Remarks. Arxellia trochos cannot be confused with any known Solariellidae species belonging to other genera. Within Arxellia, it is closest to A. maestratii (Figs 7, 85 – 93) from Vanuatu and Wallis Island area, but the latter species is smaller, has stronger carina and the intervals between the spiral cords are wider (not narrower) than the width of the cords. The new species may also be compared to A. tracheia (Figs 70 – 74) from Papua New Guinea and A. erythrea (Fig. 94 – 103) from Tonga, but in these two species the peripheral carina is formed by P 4 (not on P 5). The radula exhibits characteristic solariellid features (Herbert 1987; Hickman & McLean 1990), especially the reduced number of rows (approx. 30), highly differentiated lateral teeth (2 inner teeth similar to rachidian tooth, fourth tooth elongate and curved) and relatively few marginal teeth per row; the well-developed latero-marginal plate is similar to that found in Archiminolia, Bathymophila, Spectamen and some species referred to Solariella. This species was not included in the molecular phylogeny of Williams et al. (2013), but unpublished molecular studies confirm that it belongs in Clade A with the other species here referred to Arxellia.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA0CC445FF11FAAFFB5C9800.taxon	etymology	Etymology. Trochos (Greek: τροχζ), a potter's wheel; used as a noun in apposition — with reference to the shape of the shell, the regular whorls of which are reminiscent of a piece of hand-made pottery.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA03C440FF11FECCFDED9895.taxon	materials_examined	Type material. Holotype (11.5 x 12.7 mm) MNHN IM- 2009 - 17850. Paratypes: 5 MNHN IM- 2009 - 17851, IM- 2009 - 17849, IM- 2009 - 17852, IM- 2007 - 18220, IM- 2009 - 31844, 1 NHMUK 20140007, 1 coll. C. Vilvens CV 2014 - 18220. Type locality. Southern New Caledonia, Norfolk Ridge, NORFOLK 2, stn DW 2057, 24 ° 40 ' S, 168 ° 39 ' E, 555 – 565 m. Material examined. Southern New Caledonia and Norfolk Ridge. CHALCAL 2: stn DW 73, 23 ° 40 ' S 168 ° 38 ' E, 573 m, 19 lv, 1 dd juv. — Stn DW 74, 22 ° 40 ' S 168 ° 3, 650 m, 17 lv, 1 dd sub. — Stn DW 75, 24 ° 39 ' S 168 ° 40 ' E, 600 m, 20 lv. — BATHUS 2: stn CP 760, 22 ° 19 ' S, 166 ° 11 ' E, 455 m, 1 dd sub. — BATHUS 3: stn DW 838, 23 ° 01 ' S, 166 ° 56 ' E, 400 – 402 m, 5 lv sub. — NORFOLK 1: stn DW 1693, 24 ° 55 ' S, 168 ° 21 ' E, 564 – 1144 m, 7 lv, 3 sub lv, 3 juv lv. — Stn DW 1694, 24 ° 40 ' S, 168 ° 39 ' E, 575 – 589 m, 25 lv, 40 sub lv. — Stn DW 1695, 24 ° 40 ' S, 168 ° 39 ' E, 562 – 587 m, 25 lv, 10 sub lv. — Stn DW 1697, 24 ° 39 ' S, 168 ° 38 ' E, 569 – 616 m, 15 lv, 15 sub lv, 17 juv lv. — Stn DW 1699, 24 ° 40 ' S, 168 ° 40 ' E, 581 – 600 m, 2 lv, 6 sub lv. — Stn DW 1700, 24 ° 40 ' S, 168 ° 40 ' E, 572 – 605 m, 3 lv, 3 sub lv. — Stn DW 1701, 24 ° 40 ' S, 168 ° 39 ' E, 564 – 586 m, 7 lv, 6 sub lv. — Stn DW 1704, 23 ° 45 ' S, 168 ° 16 ' E, 400 – 420 m, 1 lv. — Stn DW 1707, 23 ° 43 ' S, 168 ° 16 ' E, 381 – 493 m, 5 lv. — NORFOLK 2: stn DW 2056, 24 ° 40 ' S, 168 ° 39 ' E, 573 – 600 m, 3 dd, 2 sub lv, 5 juv lv. — Stn DW 2057, 24 ° 40 ’ S, 168 ° 39 ' E, 555 – 565 m, 8 lv (holotype and paratypes MNHN IM- 2009 - 17851, IM- 2009 - 17849, IM- 2009 - 17852, IM- 2007 - 18220, IM- 2009 - 31844, NHMUK 20140007, coll. C. Vilvens CV 2014 - 18220). — Stn DW 2058, 24 ° 40 ' S, 168 ° 40 ' E, 591 – 1032 m, 12 lv. — Stn DW 2060, 24 ° 40 ' S, 168 ° 38 ' E, 582 – 600 m, 12 lv, 8 sub lv, 4 juv. — Stn DW 2067, 25 ° 16 ' S, 168 ° 56 ' E, 614 – 690 m, 1 dd. — Stn DW 2073, 25 ° 24 ' S, 168 ° 19 ' E, 609 m, 7 dd. — Stn DW 2074, 25 ° 24 ' S, 168 ° 20 ' E, 623 – 691 m, 5 dd. — Stn DW 2075, 25 ° 23 ' S, 168 ° 20 ' E, 650 – 1000 m, 5 dd. — Stn DW 2077, 25 ° 21 ' S, 168 ° 19 ' E, 666 – 1000 m, 1 dd. — Stn DW 2084, 24 ° 52 ' S, 168 ° 22 ' E, 586 – 730 m, 2 lv, 2 juv lv.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA03C440FF11FECCFDED9895.taxon	distribution	Distribution. Southern New Caledonia and Norfolk Ridge, 402 – 666 m, living at 402 – 650 m.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA03C440FF11FECCFDED9895.taxon	description	Description. Shell: Size relatively large for genus (height up to 11.8 mm, width up to 13.0 mm), slightly wider than high, conical; height 0.9 x width, 2.6 – 3.2 x aperture height; periphery weakly angular to almost rounded. Protoconch paucispiral, diameter approx. 330 µm, rounded, with 5 thin, equally spaced spiral threads; terminal lip straight, without varix. Teleoconch of up to 6.2 whorls; first two whorls convex, subsequent whorls almost straight; shoulder oblique with angulate rim, except on last whorl where shoulder horizontal; whorls with up to 20 spiral cords; cords thin and nearly smooth on first two whorls, thicker and beaded on subsequent whorls, beads of adapical cords stronger. Suture canaliculate on early whorls, not so on later whorls. First whorl sculptured by 6 thin, more or less equally spaced, cords; cords arising immediately after protoconch; P 1 and P 2 slightly stronger than other cords; P 1 forming rim of shoulder; close-set axial threads between cords. On second whorl, axial threads hard to distinguish and evanescing at end of whorl; P 6 at suture. Prosocline subsutural axial folds develop at start of third whorl, rendering P 1 and P 2 subgranular; P 1 and P 2 the strongest with secondary cord S 2 arising and rapidly reaching strength of P 3; P 5 thickening after middle of whorl, smooth and forming a weak suprasutural carina. On fourth whorl all adapical cords beaded, abapical cords subgranular; S 4 and S 1 arising; P 1 stronger than other cords; P 5 almost as strong as P 1, forming prominent carina above suture; shoulder more or less horizontal, suture not canaliculate; axial folds weaker, but still visible. On fifth whorl, P 6 emerging from suture; tertiary cords arising by intercalation between P 1 and S 1 and / or between S 4 and P 5. On last whorl, numerous additional tertiary cords arising, resulting in a total of up to 20 cords; carina on P 5 weaker than on penultimate whorl. Aperture subcircular; peristome incomplete; outer and inner lips thin; columella vertical, concave, the middle portion slightly reflected and overlapping umbilicus; a small flange at columella base. Base moderately convex, with 15 – 18 spiral cords; peri-umbilical region with approx. 30 axial pleats, rendering 5 – 8 most inner cords beaded; cord at umbilical rim 1.5 – 2.0 x wider than penultimate cord and strongly beaded with coarse, pointed beads; outer basal cords thin, smooth, becoming weakly beaded in central part of base, intervals between cords 1.5 – 2.0 x width of cords. Umbilicus deep, relatively narrow (diameter ca. 9 – 13 % of shell width), with angulate rim; internal wall almost straight, with 6 – 8 strong, subgranular to beaded spiral cords; cord closest to rim coarsely beaded; intervals between cords approx. 0.5 – 1.0 x width of cords. Colour: Teleoconch whorls nacreous, pinkish to orange; base white to grey; protoconch white. External anatomy (based on observation of rehydrated bodies removed from dry shells) (Fig. 41): Typical of the family. Propodium with prominent lateral lobes; snout broad with lips modified into a fringe of digitiform processes; cephalic tentacles well-developed, papillate; eyes black, situated on short stalks fused to outer side of tentacle base; right eye-stalk with a small subocular tentaculiform process; left neck lobe present as two short, nonpapillate tentacles, the right one as a trigonal outgrowth just behind eye-stalk; three papillate epipodial tentacles present on each side, of more or less equal size; between the anterior pair on both sides is a smaller tentacle-like projection, that on the right appearing to arise from the underside of an epipodial flap. Preservation of material inadequate to determine presence and position of any epipodial sense organs. Operculum corneous, straw-brown, shallowly concave, multispiral with central nucleus; growing margin short.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA03C440FF11FECCFDED9895.taxon	discussion	Remarks. The shell of Arxellia boucheti is distinctive on account of its large size, numerous spiral cords and rounded periphery. The external anatomy is almost identical to that illustrated by Warén (1993) for Solariella obscura and S. varicosa, and is also close to that of Spectamen (Herbert 1987). In the molecular analysis of Williams et al. (2013), this species forms a clade with A. tracheia and A. helicoides.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA03C440FF11FECCFDED9895.taxon	etymology	Etymology. Named after Philippe Bouchet (MNHN), whose dynamic leadership of Indo-Pacific expeditions and skilful management of malacological human resources have led to great advances in systematics and the discovery of many species new to science.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA06C442FF11FE73FCFE9B87.taxon	materials_examined	Type material. Holotype (7.0 x 7.2 mm) MNHN IM- 2009 - 28739. Paratypes: 2 MNHN IM- 2009 - 31843, IM- 2009 - 28740), 1 NHMUK 20140008. Type locality. Southern New Caledonia, Norfolk Ridge, Kaimon Maru Bank, NORFOLK 1, stn DW 1679, 24 ° 43 ’ S, 168 ° 10 ' E, 298 – 324 m. Material examined. Norfolk Ridge. BIOCAL: stn DW 66, 24 ° 55 ' S 168 ° 22 ' E, 505 – 515 m, 50 lv. — SMIB 8: stn DW 148, 24 ° 56 ' S, 168 ° 21 ' E, 510 m, 6 lv, 3 dd sub, 2 dd juv. — Stn DW 152 – 154, 23 ° 18 ' S – 23 ° 19 ' S, 168 ° 05 ' E, 305 – 367 m, 7 lv, 1 lv juv. — LITHIST: stn DW 07, 24 ° 55 ' S, 168 ° 22 ' E, 504 – 530 m, 5 lv. — NORFOLK 1: stn DW 1679, 24 ° 43 ’ S, 168 ° 10 ' E, 298 – 324 m, 4 lv (with holotype and paratype IM- 2009 - 31843). — Stn DW 1680, 24 ° 45 ’ S, 168 ° 10 ' E, 385 – 392 m, 2 dd. — Stn DW 1691, 24 ° 54 ’ S, 168 ° 22 ' E, 509 – 513 m, 11 lv (with paratypes MNHN IM- 2009 - 28740 and NHMUK 20140008)	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA06C442FF11FE73FCFE9B87.taxon	distribution	Distribution. Norfolk Ridge, 324 – 510 m (living).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA06C442FF11FE73FCFE9B87.taxon	description	Description. Shell: Size moderate for genus (height up to 7.0 mm, width up to 7.7 mm), conical, only very slightly wider than high; height 0.9 – 1.0 x width, 2.7 – 3.1 x aperture height; periphery subangular. Protoconch paucispiral, diameter approx. 350 µm, rounded, with microscopic, crisp granules, and 5 thin, equally spaced, spiral threads; terminal lip straight, without varix. Teleoconch of up to 5.2 whorls; first two whorls convex, subsequent whorls almost straight, but final whorl more convex; shoulder oblique, becoming horizontal on later whorls, with angulate rim on early whorls; whorls with up to 8 spiral cords; cords thin and almost smooth on first two whorls; on subsequent whorls, adapical cords beaded to subgranular, abapical cords smoother. Suture canaliculate on early whorls, not so on final whorl. First whorl sculptured from start by 6 thin, more or less equally spaced spiral cords; P 1 develops rapidly at rim of shoulder; P 6 close to abapical suture; faint, close-set axial threads between cords. On second whorl, P 1 stronger than other cords, P 6 at abapical suture and axial threads evanescing. Prosocline axial folds develop at start of third whorl, stronger below suture, rendering P 1 subgranular; secondary cord S 1 (holotype) or S 4 (paratype MNHN IM- 2009 - 28740) arising at start or at end of whorl, remaining weak and thin at end of whorl; P 1 strongest; P 5 strengthening but still weaker than P 1, subgranular, forming suprasutural carina. On fourth whorl, cords other than P 1 and P 5 of similar in strength, weakly subgranular; P 6 emerging from suture, smooth to weakly subgranular, rapidly approaching strength of P 5; shoulder more or less horizontal, suture not canaliculate. On fifth whorl, S 1 when present (if not then P 2) stronger than other intermediate cords, subgranular. On last whorl, S 6 arises, smooth, together with P 5 and P 6 forming a tricarinate periphery; T 2 arising above P 5, rapidly resembling P 4; T 3 arising later between P 1 and P 2, beaded. Aperture subquadrate; peristome incomplete; edge of inner lip somewhat thickened; outer lip thinner, fusing almost at a right angle with thickened base of columella. Columella vertical, weakly concave adapically; basally with a small flange and with two callus lobes, one basal the other at mid-point, partially overlapping umbilicus. Base weakly convex, almost flat; outer part with 9 – 15 faint spiral cords, difficult to discern in some specimens, resulting in a smooth appearance; 4 strong, close-set, beaded cords surrounding umbilical rim, innermost cord twice as thick as penultimate cord, pleated by thick, axially elongate nodules. Umbilicus deep, narrow (diameter ca. 6 – 10 % of shell width), rim angulate; inner wall weakly concave to almost straight, with 3 thick axial folds within. Colour: First two teleoconch whorls nacreous white; subsequent whorls nacreous pinkish-white; base nacreous white; protoconch white.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA06C442FF11FE73FCFE9B87.taxon	discussion	Remarks. Arxellia herosae is a distinctive species characterised by its bi-lobed columella callus, relatively depressed spire, tricarinate periphery and few beaded to subgranular spiral cords.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA06C442FF11FE73FCFE9B87.taxon	etymology	Etymology. Named after Virginie Héros (MNHN) whose enthusiasm, kindness and efficiency are highly appreciated by all malacologists collaborating with the MNHN.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C442FF11FD45FF7E9E3A.taxon	materials_examined	Material examined. Philippines. PANGLAO 2005: stn CP 2394, 9 ° 29 ' N, 123 ° 40 ' E, 470 – 566 m, 4 lv (MNHN 200718423, MNHN 200718424, MNHN 200718425, MNHN 200718429). — Stn CP 2399, 9 ° 32 ' N, 123 ° 42 ' E, 309 – 342 m, 1 lv juv (MNHN 200718394).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C442FF11FD45FF7E9E3A.taxon	distribution	Distribution. Philippines, 342 – 679 m, living at 242 – 470 m (including data from Poppe et al. 2006).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C442FF11FD45FF7E9E3A.taxon	description	Description (supplementary). Shell: Size small for genus (height up to 6.1 mm, width up to 5.9 mm), height and width more or less equal; spire moderately elevated, conical, periphery markedly bicarinate. Protoconch paucispiral, diameter approx. 340 µm, rounded, smooth adapically but with crisp granules and 5 thin, equally spaced, spiral threads on abapical half; terminal lip straight, without varix. Teleoconch of up to 5.7 whorls; first two whorls convex, subsequent whorls straight to weakly concave; shoulder horizontal. Early whorls with 6 spiral cords with thin, close-set axial threads in intervals; from third whorl onward, P 1 and P 5 strong and nodular, P 1 strongest; other cords and axial threads evanescing; P 5 close to suture; last whorl with 2 subsutural (P 1 and S 1), 1 suprasutural (P 5) cord and 1 cord emerging from suture (P 6), P 5 and P 6 forming 2 carinas and making a bicarinate periphery; nodules of cords adapically oriented. Columella concave, with a small basal flange fused with a strong callus to form one lobe, partially overlapping umbilicus. Base virtually flat, smooth except for two subperipheral spiral cords and one coarsely beaded spiral cord at umbilical rim, sometimes dividing into two cords. Umbilicus wide (diameter ca. 25 – 28 % of shell width) but funnel-shaped and thus narrowing internally; rim angulate and nodular. Colour: Early teleoconch whorls white, subsequent whorls nacreous bluish-white, variable between specimens; base nacreous turquoise, umbilical area bluish-white; protoconch white. Non-live collected shell is likely completely white.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C442FF11FD45FF7E9E3A.taxon	discussion	Remarks. Arxellia tenorioi clearly exhibits the conchological features distinctive of Arxellia. (e. g. conical profile, prominent P 1 and P 5, weakly reflected columella overlapping umbilicus, beaded spiral cord at rim of umbilicus). Our assignment of Arxellia tenorioi to this genus is confirmed by molecular data (Williams et al. 2013).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C45DFF11F8D8FDCA9C9E.taxon	materials_examined	Type material. Holotype (8.2 x 6.3 mm) MNHN IM- 2009 - 15188. Paratypes: 1 MNHN IM- 2009 - 15189, 1 NHMUK 20140009. Type locality. Papua New Guinea, southern seamount of Manus Island, BIOPAPUA, stn DW 3687, 3 ° 04 ' S, 147 ° 32 ' E, 305 – 579 m. Material examined. Papua New Guinea. BIOPAPUA: stn DW 3687, 3 ° 04 ' S, 147 ° 32 ' E, 305 – 579 m, 2 lv (holotype and paratype MNHN IM- 2009 - 15189). — Stn DW 3688, 3 ° 04 ’ S, 147 ° 32 ' E, 402 – 640 m, 1 lv (paratype NHMUK 20140009).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C45DFF11F8D8FDCA9C9E.taxon	distribution	Distribution. Papua New Guinea, 402 – 579 m (living).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C45DFF11F8D8FDCA9C9E.taxon	description	Description. Shell: Size moderate to large for genus (height up to 9.1 mm, width up to 7.2 mm), conical, higher than wide; height 1.3 x width, 3.9 – 4.6 x aperture height; periphery angulate; umbilicus funnel-shaped. Protoconch paucispiral, diameter approx. 300 µm, rounded, smooth adapically, but with crisp granules and two thin, equally spaced, spiral threads on abapical half; terminal lip straight, without varix. Teleoconch of up to 6.8 whorls; first two whorls convex, subsequent whorls almost straight; shoulder horizontal on early whorls, disappearing on later whorls; whorls sculptured by 8 – 12 spiral cords on last whorl. Suture not canaliculate but clearly visible. First whorl with 5 thin spiral cords arising in middle of whorl, cords of equal size and spacing; P 1 marking rim of horizontal shoulder at end of whorl, close-set axial threads clearly visible in intervals at end of whorl. On second whorl, P 1 strongest; P 3 weakening and almost vanishing at middle of whorl; axial threads fading at end of whorl; prosocline axial folds developing at beginning of whorl, stronger on subsutural area and adapical part, rendering P 1 and P 2 nodular. On third whorl, P 1 and P 5 strongest, coarsely beaded; P 5 forming weak suprasutural carina; axial folds spanning entire whorl. On fourth whorl, nodules of P 1 and P 5 adapically oriented; carina on P 5 more marked; all cords beaded; P 6 emerging from suture, beaded, weaker than other cords; shoulder oblique. On fifth whorl, P 2, P 3 and P 4 stronger; axial folds much weaker; S 4 arising, equalling P 4 in strength between end of fourth whorl (holotype) and sixth whorl (paratype 189), beaded. On sixth whorl, P 5 carina less prominent; shoulder evanescing; S 6 arising on fifth (paratype 189) or sixth (holotype) whorl, subgranular. On last whorl, all cords similar in size, except P 1 stronger and P 5 slightly stronger; carina on P 5 possibly weaker (paratype 189); tertiary cords may appear between S 4 and P 5 (holotype) or under P 5, under P 6 or between P 3 and P 4 (paratype 189). Aperture roundly quadrate, weakly oblique; peristome incomplete; outer and inner lips thin at rim; angle at base of columella weak. Columella vertical, concave, with a small basal flange fused to callus forming one lobe at mid-point, slightly overlapping umbilicus. Base flat, smooth except for 2 outer and 1 inner spiral cords; outer cords thin and smooth, inner cord forming rim of umbilicus, strongly beaded; weak axial threads on intermediate area. Umbilicus wide (diameter ca. 21 – 26 % of shell width), but funnel-shaped and thus narrower internally; rim angulate, sometimes with 2 beaded spiral cords just inside rim (holotype). Colour: Early teleoconch whorls white, subsequent whorls brownish-grey; base nacreous green, umbilical area white; protoconch white.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C45DFF11F8D8FDCA9C9E.taxon	discussion	Remarks. Arxellia helicoides superficially resembles Lamellitrochus pourtalesi (Clench & Aguayo, 1939) from the tropical western Atlantic, but although of similar size, that species has three strong nodular spiral cords on the last whorl, numerous spiral threads on the base, and a more rounded aperture. Among other Arxellia species, A. helicoides is distinctive on account of its particularly high spire (having the highest H / W ratio of ca. 1.30). In the molecular analysis of Williams et al. (2013) this species forms a clade with A. tracheia and A. boucheti.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA04C45DFF11F8D8FDCA9C9E.taxon	etymology	Etymology. Helical, helicoid (Greek: ειξ: helix and εδο: figure) — with reference to the generation of the shell, following a mathematical conical helix.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1BC45EFF11FA63FE289D25.taxon	materials_examined	Type material. Holotype (6.7 x 6.4 mm) MNHN IM- 2009 - 15183. Type locality. Papua New Guinea, Vitiaz Strait, BIOPAPUA, stn CP 3721, 6 ° 03 ’ S, 147 ° 37 ' E, 542 – 554 m. Material examined. Papua New Guinea, Vitiaz Strait. BIOPAPUA: stn CP 3721, 6 ° 03 ’ S, 147 ° 37 ' E, 542 – 554 m, 1 lv (holotype).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1BC45EFF11FA63FE289D25.taxon	distribution	Distribution. Only known from the type locality.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1BC45EFF11FA63FE289D25.taxon	description	Description. Shell: Size moderate for genus (height 6.7 mm, width 6.4 mm), conical, slightly higher than wide; height 1.05 x width, 2.9 x aperture height; periphery subangular. Protoconch paucispiral, diameter approximately 350 µm, rounded, with minute, crisp granules and 6 thin, more or less equally spaced spiral threads, adapical threads arising at half whorl; terminal lip straight, without varix. Teleoconch of up to 5.4 whorls; first two whorls moderately convex, subsequent whorls almost straight; shoulder horizontal on first three whorls, evanescing on later whorls; whorls sculptured with up to 9 spiral cords; cords thin and nearly smooth on first two whorls, thicker and beaded on following whorls; beads of adapical cords much stronger. Suture shallowly canaliculate on early whorls, not so on final whorl. First whorl convex, sculptured by 5 thin, more or less equally spaced spiral cords arising immediately except P 1 appearing a little later; P 1 at rim of shoulder, P 5 just above suture; faint, close-set axial threads in cord intervals. On second whorl, all cords similar in size; P 5 partially covered by suture; axial threads evanescing in middle of whorl. Prosocline axial folds arise during third whorl, stronger on subsutural area and adapical part, rendering P 1 beaded; P 1 and P 4 strongest, both beaded, P 1 stronger than P 4; P 4 forming suprasutural carina; P 3 weakening; secondary cord S 3 arising in middle of whorl, rapidly equalling P 3 in strength. On fourth and fifth whorls, P 1 and P 4 strongest, P 2, P 3 and S 3 weakest, P 5 of intermediate strength. On last whorl, T 1 arising at start of whorl, between P 1 and P 2; T 2 arising at same time, between S 3 and P 4, both subgranular; S 5 arsing at periphery. Aperture roundly quadrate, weakly oblique; peristome incomplete; outer and inner lips moderately thick at rim; angulation at base of columella weak. Columella vertical, shallowly concave, with small basal flange fused to strong callus and forming one lobe at midpoint, partially overlapping umbilicus. Base almost flat, with 4 thin, smooth outer cords, intervals between cords twice width of cords; median area smooth; a single strong cord with coarse, axially elongated beads marking angulate rim of umbilicus. Umbilicus superficially wide (diameter ca. 23 % of shell width), but funnel-shaped and thus narrowing internally, its wall sculptured with thin axial threads. Colour: Early teleoconch whorls greyish-blue, later whorls pinkish; base nacreous white; suture white; protoconch brownish-pink.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1BC45EFF11FA63FE289D25.taxon	discussion	Remarks. Arxellia tracheia most closely resembles A. trochos (Figs 1, 12 – 24) from southern New Caledonia, but though of similar size, that species has a more rounded periphery and differs in numerous sculptural features, namely: P 5 (not P 4) forms the suprasutural carina, all the teleoconch spiral cords are more or less similar in size, the shoulder is still present on the last whorl, there are 2 – 3 (rather than one) strong, beaded cords around the umbilicus. In the molecular analysis of Williams et al. (2013), A. tracheia forms a clade with A. boucheti and A. helicoides.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1BC45EFF11FA63FE289D25.taxon	etymology	Etymology. Uneven, rough (Greek: ταχζ, εια, υ, adjective) — with reference to the different size of the spiral cords on the shell whorls.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA19C459FF11FF3FFD3799E0.taxon	materials_examined	Type material. Holotype (7.2 x 6.2 mm) WAM S 25773. Paratypes: 1 WAM S 32251, 1 NHMUK 20140010. Type locality. Western Australia, Perth Canyon, CSIRO RV ' Southern Surveyor', stn SS 1005 / 012, 31.92 – 31.92 ° S, 115.01 – 115.02 ° E, 479 – 484 m. Material examined. Western Australia. CSIRO RV ' Southern Surveyor': stn SS 1005 / 012, 31.92 ° S, 115.02 ° E, 479 – 484 m, 1 lv (holotype WAM S 25773). — Stn SS 1005 / 095, 28.49 ° S – 28.50 ° S, 113.42 ° E – 113.43 ° E, 416 – 431 m, 2 dd (paratypes WAM S 32251 and NHMUK 20140010).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA19C459FF11FF3FFD3799E0.taxon	distribution	Distribution. Western Australia, 431 – 479 m, living at 479 – 484 m.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA19C459FF11FF3FFD3799E0.taxon	description	Description. Shell: Size moderate for genus (height 7.2 mm, width 6.3 mm), conical, slightly higher than wide; height 1.2 x width, 3.9 x aperture height; periphery subangular. Protoconch paucispiral, diameter approx. 320 – 330 µm, rounded, with minute, crisp granules on first quarter and 5 thin spiral threads; terminal lip straight, without varix. Teleoconch of up to 5.5 convex whorls; shoulder oblique with angulate rim on 3 first whorls, weaker and horizontal on later whorls; early whorls with up to 7 smooth to subgranular spiral cords, last whorl smooth. Suture canaliculate on first two whorls, not so on subsequent whorls. First whorl sculptured by 5 spiral cords present from start, the most abapical one close to suture; P 1 forming rim of shoulder; microscopic axial threads between cords; intervals between threads approximately 1.5 – 2.0 x width of threads. On second whorl, P 1 slightly stronger than other cords; secondary cord S 2 arising between middle (holotype) and end (paratype) of whorl; P 5 level with suture. On third whorl, P 1 and P 4 strongest of which P 1 clearly stronger than P 4; P 4 forming suprasutural carina; secondary S 1 and / or S 3 possibly arising between start and middle of whorl; all cords except P 1 and P 4 evanescing and hard to distinguish at end of whorl; prosocline axial folds developing at beginning of whorl, stronger on subsutural area and adapical part, rendering P 1 beaded and P 4 subgranular; axial threads fading. On fourth whorl, all cords evanescing, P 1 the last visible. Last whorl smooth. Aperture subelliptic to almost rounded, sometimes fractionally oblique; peristome incomplete; outer and inner lips moderately thick at rim; inner lip slightly projecting into umbilicus. Columella concave, its edge slightly reflected and overlapping umbilicus; a small flange at its base. Base moderately convex, essentially smooth, but with faint, thin axial threads, stronger nearer to umbilicus and producing beads on a strong spiral cord at rim of umbilicus. Umbilicus deep, relatively wide (diameter ca. 18 % of shell width), its rim angulate; internal wall weakly convex, lacking spiral cords, but with numerous, very thin axial threads. Colour: Early teleoconch whorls nacreous grey to whitish-grey; subsequent whorls greyish-blue to greyishwhite; protoconch white.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA19C459FF11FF3FFD3799E0.taxon	discussion	Remarks. Molecular data clearly show that this species belongs to Arxellia (Williams et al. 2013), but given the morphology of the shell this seems surprising, particularly in view of the reduced sculpture and almost smooth last adult whorl. However, the ontogeny of the spiral cords, with a strong abapical peripheral cord (P 4) and a strong subsutural spiral cord (P 1) are in fact features consistent with those of Arxellia. In the abovementioned molecular phylogeny, A. thaumasta was shown to be genetically very similar to a species known only from a single specimen from the Philippines. We have kept the two as separate species given that they differ morphologically and come from widely disjunct localities. The other species (Clade A, sp. 5 in Williams et al. 2013) has the beaded spiral cords typical of other Arxellia species. This species is not described here, as it is known only from a single specimen, which has been misplaced. In molecular analyses A. thaumasta and Clade A sp. 5 form the sister group to all other Arxellia species (Williams et al. 2013). Another specimen (WAM S 25779, Figs 83 – 84), from off Point Hillier, Western Australia (CSIRO RV ' Southern Surveyor', stn SS 1005 / 020, 35.3818 ° S, 117.2030 ° E to 35.3822 ° S, 117.1920 ° E, 419 – 460 m), is conchologically close to A. thaumasta, but differs most notably in that P 1 remains present on the last whorl as a beaded subsutural cord. In addition, S 2 arises much earlier (middle of first whorl), and the protoconch is slightly larger (diameter 380 µm). We have no molecular data for this specimen. Thus, it is impossible, based on a single specimen, to assert whether this is an aberrant form of A. thaumasta or a distinct species and therefore we refer to it here as A. cf. thaumasta.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA19C459FF11FF3FFD3799E0.taxon	etymology	Etymology. Surprising, unexpected, extraordinary (Greek: θυΜστζ, ον, adjective) — with reference to the smooth whorls of this unusual Arxellia species.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1FC45BFF11FEE7FCFE9879.taxon	materials_examined	Type material. Holotype (4.8 x 4.8 mm) MNHN (IM- 2000 - 27389). Paratypes: 4 MNHN (IM- 2000 - 27390), 2 NHMUK 20140011, 1 coll. C. Vilvens (CV 2009 - DW 972). Type locality. Vanuatu, MUSORSTOM 8, stn DW 972, 19 ° 22 ' S, 169 ° 28 ' E, 487 – 507 m. Material examined. Vanuatu. VOLSMAR: stn DW 51, 20 ° 59 ' S, 170 ° 03 ' E, 450 m, 3 dd, 1 dd juv. — MUSORSTOM 8: stn DW 972, 19 ° 22 ' S, 169 ° 28 ' E, 487 – 507 m, 30 dd, 5 dd juv (with holotype, paratypes IM- 2000 - 27390, paratypes NHMUK and paratype C. Vilvens). — Stn DW 977, 19 ° 25 ' S, 169 ° 29 ' E, 410 – 505 m, 2 dd. — Stn CP 963, 20 ° 20 ' S, 169 ° 49 ' E, 400 – 440 m, 1 dd. Western Pacific, Wallis Island. MUSORSTOM 7: stn DW 604, 13 ° 21 ' S, 176 ° 08 ' W, 415 – 420 m, 17 dd, 20 dd sub, 6 dd juv.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1FC45BFF11FEE7FCFE9879.taxon	distribution	Distribution. Vanuatu, 440 – 487 m (dead); Wallis Island, 415 – 420 m (dead).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1FC45BFF11FEE7FCFE9879.taxon	description	Description. Shell: Size small for genus (height up to 5.7 mm, width up to 5.2 mm), conical, slightly higher than wide; height 1.0 – 1.1 x width, 3.2 – 3.9 x aperture height; periphery subangular, tricarinate. Protoconch paucispiral, diameter approx. 320 µm, rounded, with 5 thin, unequally spaced spiral threads; terminal lip straight, without varix. Teleoconch of up to 5.5 whorls; first two whorls convex, subsequent whorls straight; shoulder oblique with angulate rim on first two whorls, horizontal thereafter; whorls with up to 8 spiral cords; cords smooth and thin on early whorls, subsequently adapical cords becoming beaded and abapical cords subgranular. Suture moderately canaliculate on early whorls, not so on final whorl. First whorl sculptured from start by 5 thin, more or less equally spaced, spiral cords; P 1 forming rim of shoulder at end of whorl; P 5 very close to suture; no axial threads visible. On second whorl, all cords remaining similar in strength. On third whorl, prosocline axial folds develop at start of whorl, stronger on subsutural area and adapical part, rendering P 1 and P 2 subgranular; secondary cord S 1 arising and rapidly equalling P 2 and P 3 in strength; P 1 strongest; P 4 strengthening but remaining weaker than P 1, subgranular, forming suprasutural carina. On fourth whorl, P 1 and P 4 strongest, P 2 and P 3 weakest, P 5 covered by suture; S 3 may arise on some specimens; shoulder more or less horizontal, suture not canaliculate. On fifth whorl, S 1 only slightly weaker than P 1, clearly beaded. On last whorl, S 5 arising and P 5 emerging from suture, almost smooth, in combination with P 4 forming a tricarinate periphery; adapical cords more strongly beaded than abapical one; sometimes with additional tertiary cords on large specimens (e. g. specimens from Wallis Is.). Aperture subcircular; peristome incomplete; inner and outer lips thin at rim; angulation at base of columella obtuse. Columella concave, with small basal flange, weakly reflected. Base almost flat, with one subperipheral cord (sometimes two in large specimens) and two strong, close-set, beaded cords bordering umbilicus, innermost of which is strongest; both peri-umbilical cords with coarse nodules; intermediate portion of base nearly smooth. Umbilicus deep, narrow (diameter ca. 6 – 10 % of shell width), funnel-shaped, with angulate rim; interior wall with 4 – 6 thick spiral cords. Colour: Early teleoconch whorls and base nacreous white; subsequent whorls nacreous pinkish-white (Vanuatu specimens) to completely white (Wallis Is. specimens); protoconch white.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1FC45BFF11FEE7FCFE9879.taxon	discussion	Remarks. Arxellia maestratii resembles A. trochos from southern New Caledonia (Figs 1, 12 – 24) but the former species has fewer, thinner and more widely spaced spiral cords, a greater H / HA ratio, a smooth median area on the base, a narrower umbilicus and peri-umbilical granules that are not elongated. Arxellia maestratii also resembles A. herosae, likewise from southern New Caledonia (Figs 5, 42 – 51), but the present species is smaller and slightly more elevated, and has P 4 (instead of P 5) forming the characteristic suprasutural carina of Arxellia. Furthermore, it has a flatter base with an umbilicus that is not appreciably occluded by any callus deposit. Since only dry material was available, there are no molecular data for this species.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1FC45BFF11FEE7FCFE9879.taxon	etymology	Etymology. Named after Philippe Maestrati (MNHN) whose availability, helpfulness and efficiency are highly appreciated by all malacologists collaborating with the MNHN.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1DC455FF11FE1FFED49AEB.taxon	materials_examined	Type material. Holotype (5.5 x 5.4 mm) MNHN IM- 2000 - 27391. Paratypes: 4 MNHN IM- 2000 - 27392, IM- 2000 - 27393, 2 NHMUK 20140012, 1 coll. C. Vilvens (CV 2014 - DW 1586). Type locality. Tonga, Vava'u group, BORDAU 2, stn DW 1586, 18 ° 34 ' S, 173 ° 55 ' W, 440 – 487 m. Material examined. Tonga. BORDAU 2: stn DW 1518, 21 ° 21 ' S, 175 ° 07 ' W, 336 – 347 m, 1 dd. — Stn DW 1544, 21 ° 18 ' S, 175 ° 18 ' W, 441 – 443 m, 8 lv, 4 dd sub (with 1 paratype MNHN IM- 2000 - 27393 and 2 paratypes NHMUK 20140012). — Stn DW 1585, 18 ° 33 ' S, 173 ° 57 ' W, 578 m, 1 dd sub (paratype CV 2014 - DW 1586). — Stn DW 1586, 18 ° 34 ' S, 173 ° 55 ' W, 440 – 487 m, 13 lv (with holotype and 3 paratypes MNHN IM- 2000 - 27392). Wallis and Futuna Islands area. Wallis Island, MUSORSTOM 7: stn DW 523, 13 ° 12 ' S, 176 ° 16 ' W, 455 – 515 m, 1 dd. — Stn DW 608, 13 ° 22 ' S, 176 ° 08 ' W, 440 – 458 m, 2 dd sub. — Waterwitch Bank, MUSORSTOM 7: stn DW 535, 12 ° 30 ' S, 176 ° 41 ' W, 340 – 470 m, 1 dd sub. — Stn DW 537, 12 ° 30 ' S, 176 ° 41 ' W, 325 – 400 m, 1 lv.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1DC455FF11FE1FFED49AEB.taxon	distribution	Distribution. Tonga, 347 – 578 m (living at 441 – 443 m); Wallis and Futuna Islands area, 400 – 455 m (living at 325 – 400 m).	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1DC455FF11FE1FFED49AEB.taxon	description	Description. Shell: Size small for genus (height up to 5.7 mm, width up to 5.4 mm), conical, slightly higher than wide; height 1.0 – 1.2 x width, 3.6 – 3.9 x aperture height; periphery subangular. Protoconch paucispiral, diameter approx. 300 – 310 µm, rounded, with 5 thin, equally spaced spiral threads; terminal lip straight, without varix. Teleoconch of up to 5.2 whorls; first two whorls moderately convex, subsequent whorls almost straight; shoulder oblique, with angulate rim on early whorls, horizontal on later whorls; whorls sculptured by up to 12 spiral cords, with peripheral cord forming a carina; adapical cords beaded, other cords subgranular to nearly smooth. Suture canaliculate on early whorls, not so on final whorl. First whorl sculptured from start by 5 thin, more or less equally spaced, spiral cords; P 1 rapidly forming rim of shoulder; P 5 soon level with suture; faint, close-set axial threads between cords. On second whorl, P 1 stronger than other cords; S 1 arising in middle of whorl and axial threads evanescing. On third whorl, prosocline axial folds develop, stronger on subsutural area and adapical part, rendering P 1 subgranular; P 1 and P 5 strongest, P 5 smooth, forming weak suprasutural carina; P 3 and P 4 very weak; P 6 emerging from suture. On fourth whorl, P 1 and P 2 coarsely beaded, other cords nearly smooth; P 5 forming strong carina; P 3 and P 4 stronger; S 3, S 4 and S 5 arise near end of whorl or at beginning of next whorl. On fifth whorl, additional tertiary cords may arise, especially one cord between suture and P 1, rapidly becoming beaded; shoulder more or less horizontal, suture not canaliculate; axial folds much weaker, but still visible. On last whorl, S 6 arising at periphery, number of spiral cords reaching 12. Aperture subcircular; peristome incomplete; outer and inner lips slightly thickened at rim; columella vertical, shallowly concave, its edge weakly reflected; a small flange sometimes present at columella base. Base almost flat, with 3 – 4 thin, smooth spiral cords below periphery, a nearly smooth median area and 2 – 3 strong, beaded, peri-umbilical cords; innermost cord forming rim of umbilicus, at least twice as thick as penultimate cord, with coarse, weakly pointed beads. Umbilicus deep, wide (diameter ca. 22 – 32 % of shell width), funnel shaped, with angulate rim, interior wall almost straight, bearing 6 – 7 equally spaced, strong, smooth spiral cords; intervals between spiral cords 0.5 – 1.0 x width of cords. Colour: First three teleoconch whorls white; subsequent whorls reddish or pinkish with a whitish subsutural area; base nacreous pinkish-white to white; protoconch white.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1DC455FF11FE1FFED49AEB.taxon	discussion	Remarks. Arxellia erythrea resembles the type species Arxellia trochos from southern New Caledonia (Figs 1, 12 – 24) but the present species is a little smaller and more depressed, has thinner and more numerous spiral cords on the whorls, of which P 5 forms a more prominent suprasutural cord. In addition, it has a greater H / HA ratio and the colour is predominantly reddish (instead of white to greyish-blue). Since only dry material was available, there are no molecular data for this species.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
E518B10EDA1DC455FF11FE1FFED49AEB.taxon	etymology	Etymology. Red (Greek: ερυθροζ, α, ον adjective) — referring to the red background colour of the adult shell whorls. We thank P. Bouchet (MNHN) for reading the manuscript, constructive advice and access to the malacological resources of the MNHN and Carole Hickman and Bruce Marshall for valuable comments that resulted in an improved manuscript. We are also grateful to V. Héros, B. Buge, P. Maestrati and N. Puillandre (MNHN) for sorting samples and providing locality data, and B. Buge, V. Héros and A. Salvador (NHMUK) for providing registration numbers. Special thanks go to A. Warén (SMNH) for his careful analysis and sorting of the huge MNHN collection of solariellid material and to H. Taylor (NHMUK photo unit) for taking photos of holotypes. We also gratefully acknowledge S. Slack-Smith, C. Whisson and J. Fromont (WAM) for the loan of type material from their institution.	en	Vilvens, Claude, Williams, Suzanne T., Herbert, David G. (2014): New genus Arxellia with new species of Solariellidae (Gastropoda: Trochoidea) from New Caledonia, Papua New Guinea, Philippines, Western Australia, Vanuatu and Tonga. Zootaxa 3826 (1): 255-281, DOI: 10.11646/zootaxa.3826.1.8
