Arxellia tenorioi ( Poppe, Tagaro & Dekker, 2006 )

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), pp. 255-281 : 269

Arxellia tenorioi ( Poppe, Tagaro & Dekker, 2006)

( Figs 5 , 52–62 )

Bathymophila tenorioi— Poppe, Tagaro & Dekker, 2006: 128–129, pl. 77, figs 1–2. Type locality: Philippines, off Balicasag Island, PANGLAO 2005, stn CP2394, 9°29'N, 123°40'E, 470– 566 m.

Clade A, tenorioi — Williams et al., 2013.

Material examined. Philippines. PANGLAO 2005: stn CP2394, 9°29'N, 123°40'E, 470–566 m, 4 lv ( MNHN 200718423, MNHN 200718424, MNHN 200718425, MNHN 200718429).—Stn CP2399, 9°32'N, 123°42'E, 309–342 m, 1 lv juv ( MNHN 200718394).

Distribution. Philippines, 342–679 m, living at 242–470 m (including data from Poppe et al. 2006).

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, P1 and P5 strong and nodular, P1 strongest; other cords and axial threads evanescing; P5 close to suture; last whorl with 2 subsutural (P1 and S1), 1 suprasutural (P5) cord and 1 cord emerging from suture (P6), P5 and P6 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.

Remarks. Arxellia tenorioi clearly exhibits the conchological features distinctive of Arxellia . (e.g. conical profile, prominent P1 and P5, 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).

Figures

FIGURES 1 – 9. Arxellia new species, all holotypes except A. tenorioi. 1, A. trochos, n. sp., type species of Arxellia n. gen. 2, A. boucheti n. sp. 3, A. herosae n. sp. 4, A. helicoides n. sp. 5, A. tenorioi n. sp. 6, A. tracheia n. sp. 7, A. maestratii n. sp. 8, A. thaumasta n. sp. 9, A. erythrea n. sp. Scale bar = 5 mm.

FIGURES 52 – 62. Arxellia tenorioi (Poppe, Tagaro & Dekker, 2006); Philippines, off Balicasag Island. 52 – 57, MNHN (200718429), 470 – 566 m [PANGLAO 2005, stn CP 2394]. 52 – 54, shell, 4.9 x 5.3 mm. 55 – 56, details of protoconch and early whorls. 57, details of columella and umbilicus. 58 – 59, MNHN (200718424), 470 – 566 m [PANGLAO 2005, stn CP 2394], 5.1 x 5.3 mm. 60, MNHN (200718425), 470 – 566 m [PANGLAO 2005, stn CP 2394], 6.1 x 5.9 mm. 61, subadult specimen MNHN (200718423), 470 – 566 m [PANGLAO 2005, stn CP 2394], 4.3 whorls, 3.2 x 3.3 mm. 62, juvenile specimen MNHN (200718394), 309 – 342 m [PANGLAO 2005, stn CP 2399], 1.5 x 1.8 mm. Scale bars = 1 mm, except figs. 55, 56: 100 µm, fig. 57: 1 mm.