Hungerfordia papilio papilio K. Yamazaki and Ueshima, 2013

YAMAZAKI, KAZUNORI, YAMAZAKI, MIDORI & UESHIMA, REI, 2013, <p> <strong> Systematic review of diplommatinid land snails (Caenogastropoda, Diplommatinidae) endemic to the Palau Islands. (1) Generic classification and revision of <em> Hungerfordia </ em> </ strong> <br /> <strong> species with highly developed axial ribs </ strong> </ p>, Zootaxa 3743 (1), pp. 1-71 : 58-61

Hungerfordia papilio papilio K. Yamazaki and Ueshima sp. et subsp. nov.

( Figs. 9N , 27 , 29K )

Hungerfordia J: Rundell, 2010, p. 88, Table 2.

Hungerfordia sp. nov. J: Webster et al., 2012, pp. 625-638. Materials examined. Holotype. “Milky way", southern coast of central part of Ngeruktabel island (Loc. Gk2-2), Palau. Collected by R. U. and K. Y. on July 12, 2006. UMUTZ-MG-B0434 T. Paratypes. Ngeruktabel: Loc. Gk 2- 2, 11 specimens, 11/XI/2004, UMUTZ-MG-B0162; ditto, 33 specimens, 12/VII/2006, UMUTZ-MG-B0434; Loc. Gk3-1, 22 specimens, 2/VII/2005, UMUTZ-MG-B0271; Loc. Gk4-5, 11 specimens, 11/VII/2006, UMUTZ-MG- B0394; Loc. Gk4-6, 5 specimens, 11/VII/2006, UMUTZ-MG-B0409; Loc. Gk5-1, 34 specimens, 17/XI/2006, UMUTZ-MG-B0603; Loc. Gk7-3, 35 specimens, 29/I/2010, UMUTZ-MG-B0963; Loc. Gk8-6, 19 specimens, 2/ III/2011, UMUTZ-MG-B1368. Ngebedangel islet of Ngeruktabel: Loc. Gk6-3, 25 specimens, 26/X/2007, UMUTZ-MG-B0858. Ongael and other satellite islets of Ngeruktabel: Loc. Gk1-2, 27 specimens, 10/XI/2004, UMUTZ-MG-B0143; Loc. Gk4-2, 40 specimens, 10/VII/2006, UMUTZ-MG-B0361; Loc. Gk4-3, 55 specimens, 10/VII/2006, UMUTZ-MG-B0374. Babelomekang: Loc. Om5-1, 3 specimens, 15/XI/2006, UMUTZ-MG-B0574; Loc. Om7-1, 25 specimens, 29/I/2010, UMUTZ-MG-B0992 .

Diagnosis. Shell sinistral, large to very large for Hungerfordia species , slender conical. Shell color semitransparent, upper whorls occasionally yellow. Constriction located above the aperture, associated with abrupt reduction of wing-like ribs. Axial ribs on most whorls strongly protruded as wings, very widely spaced at a constant interval of 7 ribs in a whorl, completely synchronized with those on the previous whorls except the last whorl, hardly folded at the periphery; wing-like projections of the ribs very high, thin, fragile, almost flat, extremely wide, arising at the suture, firstly extended upward slightly beyond the suture, then overlapped with those on the previous whorls; ribs above the aperture very closely spaced, very low, without wing-like projections; ribs on the last 3/4 whorls highly and very widely protruded as wings again, with wing-like projections which are separated from those on the previous whorls. Spiral sculptures fine, frequently reduced on lower whorls. Axial protrusions of shell wall (along the ribs) strongly developed on the last 3/4 whorls; abapertural and adapertural sides equally wide and concave in umbilical view. Umbilicus opened. Aperture more or less protruded. Columellar tooth absent. Peristome double, very widely expanded; outer peristome thin, fragile, very widely expanded beyond the inner one at the palatal and basal sides, often with rounded palatal and baso-columellar edges; inner peristome subcircular, widely expanded all around, parietal margin located below the middle level of the upper body whorl. Interspace between the inner and outer peristomes usually wide, smooth on the outer surface.

Description. Shell ( Figs. 27A–J , 29K ). Shell sinistral, large to very large for Hungerfordia species , slender conical, last whorl widest when removing the protruded ribs and peristomes. Shell color semi-transparent throughout the whorls, upper whorls occasionally yellow-colored with the color becoming deeper towards the apex. Whorls 7–8, convex; last 1/16–1/8 whorls (including interspace between the outer and inner peristomes) expanded upward and weakly ascending onto the penultimate whorl in left lateral view. Suture impressed. Constriction located above the parietal/columellar junction of the aperture, associated with abrupt reduction of wing-like ribs, internally without palatal plica except a low and axial crest caused by the constriction. Tuba 7/8 whorls. Protoconch 1.25–1.5 whorls, smooth on the apical whorl, weakly and finely punctated on the lower whorl. Apical septum absent. Axial ribs developed on the teleoconch, very widely protruded as wings on most whorls: ribs undeveloped on the first 1/4 whorls of the teleoconch; ribs on the following 1/4–1/3 whorls of initial teleoconch low, moderately or widely spaced, not folded; ribs on the subsequent whorls (except the body whorl) very widely and highly protruded as wings, very widely spaced at a constant interval of 7 ribs in a whorl, completely synchronized with those on the previous whorls, hardly folded at the periphery; wing-like projections of the ribs very high, very wide, thin, very fragile, almost flat, with rounded tip, protruded rather upward, arising at the suture, firstly extended upward slightly beyond the suture, then overlapped with those on the previous whorls with a narrow slit above the suture, lower margin also widely expanded below and somewhat exceeded beyond the suture of the next whorl, with fine and weak spiral sculptures on the outer surface; ribs above the aperture (ribs on the last 1 to last 5/8 whorl around the constriction) abruptly becoming very closely spaced and very low, without wing-like projections, very low, fine; ribs on the last 3/4 whorls highly and very widely protruded as wings again, widely spaced as those on the upper whorls, but not synchronized with and clearly separated from those on the previous whorls, weakly folded or curled above the periphery, upper margin above the wing (between the suture and wing) low; wing-like projections of the ribs high, very wide, protruded rather downward, arising at the suture just after the constriction, then becoming to arising at some distance below the suture (near periphery of the whorl) on the last 5/8 whorls, upper margin of the wings weakly folded or curled over the lower margin. Spiral sculptures present on the teleoconch, fine, very weak, frequently reduced on lower whorls, rather prominent on the outer surface of the wing-like ribs, sinuous in high magnification. Interspace between the wing-like ribs almost smooth on most whorls, with weak growth wrinkles on lower whorls; upper growth wrinkles present below the suture on the last 5–8 whorls, fine, very low; lower growth wrinkles occasionally present above the suture of the last whorl, very weak, short, almost vertical. Base convex, without basal keel. Axial protrusions of shell wall (along the ribs) strongly developed on the last 3/4 whorls, hidden by the wing-like projections; abapertural and adapertural sides equally wide and concave in umbilical view. Umbilicus opened clearly in adult, width of 7–14 % of the shell diameter (including the expanded ribs and outer peristome), with some very low, fine and/or rather coarse growth wrinkles around it. Aperture circular, hardly tilted against the coiling axis, hardly to strongly protruded; columellar axis within aperture almost vertical. Columellar tooth never developed at all. Peristome double, widely expanded; outer peristome thin, fragile, very widely expanded beyond the inner one at the palatal and basal sides, often with rounded palatal and baso-columellar edges, smooth and polished on the inner surface; inner peristome subcircular or squarish circular, widely expanded all around, more or less protruded from the outer one, upper palatal or angular margin weakly protruded forward, palatal margin slightly concave in left lateral view, basal margin weakly concave in umbilical view, parietal margin located below the middle level of the upper body whorl. Interspace between the inner and outer peristomes usually wide (a specimen, shown in Fig. 27A 2 , has an unusually narrow interspace between the peristomes), smooth on the outer surface; uppermost margin weakly ascending onto the penultimate whorl toward the aperture in left lateral view; base abruptly expanded toward the aperture in left lateral view.

Dimensions. Shell height 4.8–6.7 mm, diameter 3.8–5.5 mm, suture width 1.9–2.7 mm, peristome height 1.6– 2.3 mm.

Operculum ( Figs. 27K 1 –K 4 ). Operculum corneous, multispiral, circular, transparent, amber colored, thin, flat, slightly concave; outer surface smooth; inner surface with a low, weak, arcuate ridge near the columellar margin.

Penis. Penis absent.

Radula ( Fig. 9N ). Radula of specialized type of taenioglossate; ribbon very long. Central tooth very large, with a very wide, large, and blunt central cusp, without lateral cup, basal plate longitudinally elongated and strongly constricted at the base. Lateral teeth also large, with a large, very wide and blunt major cusp, without inner nor outer cusp. Inner marginal teeth narrower and shorter than the lateral teeth, with a large major cusp, with two slender inner cusps, with a reduced outer cup. Outer marginal teeth shorter than the inner marginals, with a large and blunt major cusp, with a slender inner cusp, without outer cusp.

Distribution and ecology. Endemic to Palau: Ngeruktabel island, its satellite islets, and Babelomekang island. The species inhabits vertical walls of large limestone rocks or cliffs, occasionally on limestone rubbles.

Remarks. H. papilio papilio is easily distinguished from all other Hungerfordia species with wing-like ribs by the characteristic wing-like ribs, opened umbilicus, complete reduction of the wing-like projections above the aperture, and the absence of columellar tooth. The wing-like ribs on upper whorls (higher than the last whorl) are extremely wide, almost flat, overlapped with and synchronized with those on the previous whorls, and very widely spaced at a constant interval of 7 ribs in a whorl.

Etymology. The specific name, derived from Latin papilio (= butterfly), refers to the extremely wide and wing-like axial ribs.

Figures

FIGURE 1. Map of Palau islands showing collecting sites. Small red circles show collecting sites. Areas encircled by blue rectangles are shown as enlarged maps in Figs. 2–5. Abbreviations of the collecting sites are listed in Table 2.

FIGURE 9. Radulae of Hungerfordia species. (A) H. pelewensis Beddome, 1889, B0283; (B) H. triplochilus sp. nov., topotypic paratype, B0158; (C) H. expansilabris sp. nov., topotypic paratype, B1299; (D) H. nudicollum sp. nov., topotypic paratype, B0364; (E) H. echinata echinata sp. et subsp. nov., paratype, B1084; (F) H. echinata tubulispina subsp. nov., topotypic paratype, B0169; (G) H. elegantissima sp. nov., topotypic paratype, B0375; (H) H. goniobasis goniobasis sp. et subsp. nov., topotypic paratype, B0235; (I) H. goniobasis dmasechensis subsp. nov., topotypic paratype, B0579; (J) H. lamellata (Crosse, 1866), B0157; (K) H. subalata sp. nov., paratype, B0021; (L) H. pteropurpuroides sp. nov., topotypic paratype, B1116; (M) H. alata (Crosse, 1866), B1041; (N) H. papilio papilio sp. et subsp. nov., paratype, B0374; (O) H. papilio stenoptera subsp. nov., paratype, B0761. Scale bars, 10 µm. All specimens, UMUTZ-MG.

FIGURE 27. Hungerfordia papilio papilio sp. et subsp. nov. (A1–A4) A paratype from Loc. Gk4-3, B0374a; (B) columella (dorsal view), (C) axial ribs above the aperture, and (D) sculpture on the last 2–4 whorls of paratypes from Loc. Gk4-3 (B0374a, b); (E) a paratype after removal of the winged ribs, Loc. Gk4-3, B0374c; (F) a paratype from Gk4-3, B0374d; (G1– G4) holotype, B0434T; (H) a paratype from Loc. Gk6-3, B0858; (I) a paratypes from Loc. Gk7-3, B0963; (J) umbilical view of a paratype after removal of the winged ribs, Loc. Gk4-3, B0374c; (K1, K2) outer surface, and (K3, K4) inner surface of operculum of a paratype, Loc. Gk4-3, B0374. Scale bars, 1mm (A–J), 0.5 mm (K). All specimens, UMUTZ-MG.

FIGURE 29. Shell size and shape variation among Hungerfordia species with highly developed ribs. (A) H. triplochilus sp. nov., holotype; (B) H. expansilabris sp. nov., holotype; (C) H. nudicollum sp. nov., holotype; (D) H. echinata echinata sp. et subsp. nov., holotype; (E) H. echinata tubulispina subsp. nov., holotype; (F1) H. lamellata (Crosse, 1866), B0199a; (F2) H. lamellata (Crosse, 1866), B0282b; (G) H. alata (Crosse, 1866), B0446; (H) H. pteropurpuroides sp. nov., holotype; (I1) H. subalata sp. nov., paratype (B0655); (I2) H. subalata sp. nov., holotype; (J) H. papilio stenoptera subsp. nov., holotype; (K) H. papilio papilio sp. et subsp. nov., holotype; (L) H. goniobasis dmasechensis subsp. nov., holotype; (M) H. goniobasis goniobasis sp. et subsp. nov., holotype; (N) H. elegantissima sp. nov., holotype; (O1) H. pelewensis Beddome, 1889, B0542; (O2) H. pelewensis Beddome, 1889, B0383. Scale bar, 1mm. All specimens, UMUTZ-MG.

FIGURES 2–3. Enlarged maps of Palau islands showing collecting sites. Top (Fig. 2), map of southern part of Babeldaob island; bottom (Fig. 3), map of Koror island and its neighboring islands or islets. Abbreviations of the collecting sites are listed in Table 2.

FIGURES 4–5. Enlarged maps of Palau islands showing collecting sites. Top (Fig. 4), map of Ngerkutabel island and its neighboring islands or islets; bottom (Fig. 5), map of Mecherchar island and its neighboring islands or islets. Abbreviations of the collecting sites are listed in Table 2.