Hungerfordia lamellata ( Crosse, 1866 ) YAMAZAKI & YAMAZAKI & 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 : 44-48

Hungerfordia lamellata ( Crosse, 1866) comb. nov.

( Figs. 9J , 21 , 22 , 29F )

Palaina lamellata: Semper, 1865 , name only (nom. nud.), p. 292.

Palaina lamellata: Crosse, 1866, p. 348 , pl. X, fig.2.

Diplommatina lamellata: Pfeiffer, 1876a, pp. 18-19 .

Diplommatina (Palaina) lamellata: Pfeiffer, 1876b, p. 398 .

Diplommatina (Pseudopalaina) lamellata: Kobelt & Moellendorff, 1898, p. 139 .

Diplommatina (Pseudopalaina) lamellata: Kobelt, 1902, p. 453 .

Hungerfordia A in part: Rundell, 2010, pp. 86, 88, Table 2.

Hungerfordia sp. nov. A: Webster et al., 2012, pp. 625-638.

Materials examined. Syntype. Peleliu, single specimen, MNHN 26604 (Muséum National d’Histoire Naturelle, Paris) . Additional materials. Babeldaob: Loc. BA 4-1, 35 specimens, 7/VII/2006, UMUTZ-MG-B0282; Loc. BA 5-2, 24 specimens, 12/XI/2006, UMUTZ-MG-B0445; Loc. BA 6-3, 14 specimens, 21/X/2007, UMUTZ-MG- B0678; Loc. BA 6-4, 14 specimens, 21/X/2007, UMUTZ-MG-B0689; Loc. BA 8-3, 3 specimens, 1/III/2011, UMUTZ-MG-B1310; Loc. BA 8-4, 6 specimens, 1/III/2011, UMUTZ-MG-B1323; Loc. BA 8-5, 1 specimen, 1/III/ 2011, UMUTZ-MG-B1333. Koror and its satellite islets: Loc. Ko2-1, 37 specimens, 6/XI/2004, UMUTZ-MG- B0044; Loc. Ko2-1, 7 specimens, 2/II/2010, UMUTZ-MG-B1130; Loc. Ko2-2, 130 specimens, 7/XI/2004, UMUTZ-MG-B0059; ditto, 9 specimens, 28/VI/2005, UMUTZ-MG-B0179; Loc. Ko3-1, 39 specimens, 27/VI/ 2005, UMUTZ-MG-B0178; Loc. Ko5-1, 35 specimens, 13/XI/2006, UMUTZ-MG-B0490; Loc. Ko5-2, 49 specimens, 13/XI/2006, UMUTZ-MG-B0495; Loc. Ko5-3, 3 specimens, 13/XI/2006, UMUTZ-MG-B0504; Loc. Ko5-5, 48 specimens, 14/XI/2006, UMUTZ-MG-B0532; Loc. Ko6-1, 52 specimens, 21/X/2007, UMUTZ-MG- B0699; Loc. Ko8-1, 31 specimens, 3/III/2011, UMUTZ-MG-B1410; Loc. Ko5-6, 24 specimens, 14/XI/2006, UMUTZ-MG-B0541; Loc. Ko8-2, 41 specimens, 3/III/2011, UMUTZ-MG-B1419. Ngerchaol: Loc. Ch5-1, 25 specimens, 14/XI/2006, UMUTZ-MG-B0524; Loc. Ch6-1, 10 specimens, 22/X/2007, UMUTZ-MG-B0710; Loc .

Ch6-2, 29 specimens, 22/X/2007, UMUTZ-MG-B0719; Loc. Ch8-1, 26 specimens, 3/III/2011, UMUTZ-MG- B1389; Loc. Ch8-2, 6 specimens, 3/III/2011, UMUTZ-MG-B1397. Ngermalk: Loc. Nm4-1, 49 specimens, 8/VII/ 2006, UMUTZ-MG-B0317; ditto, 19 specimens, 13/XI/2006, UMUTZ-MG-B0519. Ulebsechel: Loc. Ub3-1, 42 specimens, 28/VI/2005, UMUTZ-MG-B0199; Loc. Ub6-1, 26 specimens, 22/X/2007, UMUTZ-MG-B0748; Loc. Ub7-1, 37 specimens, 31/I/2010, UMUTZ-MG-B1040; Loc. Ub7-2, 6 specimens, 31/I/2010, UMUTZ-MG-B1061; Loc. Ub7-3, 31 specimens, 31/I/2010, UMUTZ-MG-B1070; Loc. Ub7-4, 7 specimens, 31/I/2010, UMUTZ-MG- B1082; Loc. Ub8-1, 90 specimens, 3/III/2011, UMUTZ-MG-B1430 .

Diagnosis. Shell sinistral, large to very large for Hungerfordia species , slender conical. Shell color usually orange. Constriction located above the aperture, associated with abrupt reduction of the spiny ribs, frequently followed by a prominent whorl swelling, internally with one or two axial (radial) palatal plicae. Apical septum absent. Axial ribs strongly developed on most whorls; ribs on the first 1/3–1/2 whorls low, closely spaced; ribs on the subsequent whorls strongly protruded as wings, widely spaced to very widely spaced, folded at the periphery; upper margin of the ribs above the wing-like projections (between the suture and wing) low; wing-like projections of the ribs very high, wide, arising at some distance below the suture; ribs above the aperture low, closely spaced, with greatly reduced wing-like projections (but still retaining at least low wings). Spiral sculptures fine. Aperture hardly tilted. Columellar tooth absent, or invisible in front view but developed deeply inward. Peristome double, widely expanded; outer peristome expanded beyond the inner one; inner peristome also expanded, parietal margin located near or below the middle level of the upper body whorl. Interspace between the inner and outer peristomes variable from narrow to wide, with or without some lamellar ribs or very low riblets on the outer surface. Shell size, color, and sculpture highly variable among populations.

Description. Shell ( Figs. 21A–K 2 , 22A 1 –A 7 , 22C , 29F 1 –F 2 ). Shell sinistral, large to very large for Hungerfordia species , slender conical, last whorl widest when removing the expanded ribs and peristomes. Shell color orange, variable from bright reddish orange to faint orange (almost white), apical whorls occasionally yellow-colored with the color becoming deeper towards the apex. Whorls 6–7, convex; last 1/8 whorls (including interspace between the outer and inner peristomes) expanded upward and 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 spiny ribs, frequently followed by a prominent whorl swelling, internally with one or two axial (radial) palatal plicae that are visible from outside through the shell: posterior axial plica located just after the constriction, rather wide, flat thickening of palatal wall, arising at the constriction but the abapertural margin occasionally obscure, adapertural margin frequently delineated by an abrupt (almost vertical) thickening from the palatal wall; anterior axial plica located just after the posterior plica, thin, sharp, occasionally reduced to various degrees. Tuba 7/8 whorls. Protoconch 1+1/8 to 1.5 whorls, apical whorl almost smooth, lower whorl faintly and finely punctated in high magnification. Apical septum absent. Axial ribs developed on the teleoconch, oblique to the coiling axis, strongly developed as wings on most whorls; ribs on the first 1/3–1/2 whorls of the teleoconch low, closely spaced, not folded; ribs on the subsequent whorls (except above the aperture) highly and widely protruded as wings, variable in the rib density from widely spaced (14–16 ribs in a whorl) to very widely spaced (10–11 ribs in a whorl), not synchronized with those on the previous whorls, strongly folded at the periphery; upper margin of the ribs above the wing-like projections (between the suture and wing) low, indistinct or slightly elevated; winglike projections of the ribs very high, wide to rather narrow, white, curved upward, weakly pointed at the shoulder, arising at some distance below the suture (near periphery of a whorl), folded at the periphery, upper margin weakly folded over the lower margin, lower margin widely extended below to suture of the next whorl, protruded upward on most whorls, becoming protruded laterally on the last 3/4 whorls, with fine spiral sculptures on the outer surface; ribs above the aperture (ribs on the last 1+1/8 to last 3/4 whorls around the constriction) abruptly becoming closely spaced and low, with greatly reduced wing-like projections (but still retaining at least low wing-like projections), gradually becoming less folded at the periphery towards the constriction, wing-like projections also becoming more reduced towards the constriction. Interspace between the wing-like ribs with or without growth wrinkles; growth wrinkles occasionally present below suture on the last 2 whorls, fine, very low. Spiral sculptures present throughout teleoconch, fine, weak, rather prominent below periphery, extended on outer surface of the wing-like ribs and outer peristome, occasionally reduced in lower whorls, sinuous in high magnification. Base convex, without basal keel. Axial protrusions of shell wall (along the ribs) weakly developed on the last 3/4 whorls. Umbilicus closed in adult. Aperture hardly tilted against the coiling axis, hardly protruded; columellar axis within aperture almost vertical. Columellar tooth completely reduced or weakly developed inward, invisible from the aperture even when present, occasionally appeared deeply inside the aperture as a weak swelling of columella or a rather sharply protruded tooth. Peristome double, widely expanded; outer peristome expanded beyond the inner one at the palatal and basal sides, occasionally with rounded baso-columellar and palatal edges, smooth or with growth wrinkles on the inner surface; inner peristome circular or squarish circular, expanded all around, hardly reflected backward, protruded from the outer one in various degrees, parietal margin located near or slightly below the middle level of the upper body whorl, upper palatal (angular) margin weakly angulate and somewhat protruded forward in left lateral and umbilical views or not. Interspace between inner and outer peristomes variable, narrow to wide, with or without some lamellar libs or a series of very low riblets on the outer surface; uppermost margin ascending onto the penultimate whorl toward the aperture in left lateral view.

Dimensions. Shell height 4.9–7.2 mm, diameter 3.5–6.1 mm, suture width 2.2–2.9 mm, peristome height 1.8– 2.8 mm.

Operculum ( Figs. 21L 1 –L 4 ). Operculum corneous, multispiral, circular, thin, transparent, amber colored, almost flat or weakly concave; outer surface smooth; inner surface with a low, thin, arcuate ridge.

Penis. Penis absent.

Radula ( Fig. 9J ). Radula of specialized type of taenioglossate; ribbon very long. Central tooth very large, with a very wide, large, and blunt central cusp, with or without one or two pairs of vestigial lateral cups, 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, basal plate obliquely elongated. Inner marginal teeth shorter than the lateral teeth, elongated, with a wide major cusp, with two slender inner cusps, with a small outer cup. Outer marginal teeth shorter than the inner marginals, with a large, wide and blunt major cusp, with two slender inner cusps, without outer cusp.

Local variation. H. lamellata shows substantial local variations in its shell size, shell color, development and density of the wing-like ribs, development of the columellar tooth, development of a whorl swelling after the constriction, and width and sculpture of interspace between the inner and outer peristomes. For example, Ulebsechel populations are characterized by having a large and reddish orange-colored shell, widely spaced and very high wing-like ribs, a constriction followed by a weak whorl swelling, and a narrow interspace between the inner and outer peristomes ( Figs. 21A 1 –A 4 , 21F 1 –F 4 ). Whereas, specimens collected from some Babeldaob populations show a distinctive shell morpho-type: the shells are distinctly smaller, faint colored (almost white), with more closely spaced and shorter wing-like ribs ( Figs. 21G 1 –G 3 ). In addition, the inner peristome is strongly protruded from the outer one, and the constriction is followed by an abrupt whorl swelling ( Figs. 21G 1 –G 3 ). Interspace between the outer and inner peristomes is wide and with some lamellar ribs on its surface in some populations ( Figs. 22A 3 , 22C ), but is narrower and with or without a series of very low riblets in other populations ( Figs. 21A 2 , 21F 2 , 21G 2 ). Columellar tooth is also variable among populations. Columellar tooth is reduced in most populations ( Fig. 21K 1 ), but is sharply protruded deeply inward in some Koror populations ( Fig. 21K 2 ). Such divergent morpho-types, however, are not clearly distinguished from each other. Intermediate morpho-types occur in various character combinations ( Figs. 21A–J , 22C ). In addition, all these morphs share the diagnostic features of H. lamellata , such as the presence of the characteristic axial palatal plica inside the constriction, somewhat orange shell color, and the absence of apical septum etc. Therefore, we regard H. lamellata as a single species showing extensive local variations.

Distribution and ecology. Endemic to Palau: Babeldaob (southern coastal limestone area), Koror (eastern limestone area), Ngerchaol, Ngermalk, Ulebsechel islands and their satellite islets. The species inhabits vertical walls of large limestone rocks or cliffs, occasionally on limestone rubbles.

Remarks. H. lamellata was poorly defined and figured in the original description ( Crosse 1866). Our examination of the syntype revealed some additional characters diagnostic of the species. These include the absence of apical septum, the initial half whorl of the teleoconch with closely spaced ribs, and the presence of an abrupt swelling of whorl after the constriction ( Figs. 22A 6 –A 7 ). The wing-like ribs were almost broken in the syntype and the ground shell color was faded over 140 years ( Figs. 22A 1 –A 6 ). The syntype is unusual only in having two vague brown bands just behind the aperture (one below the suture and the other one around the columella). The locality of the type specimen is noted as “ Peleliu ” by Crosse (1866). The type locality, however, may be incorrect, because distribution range of the species is far north from the island. H. lamellata is redescribed here as a Hungerfordia species with extensive intra-specific variations.

H. lamellata is distinguished from other Hungerfordia species with wing-like ribs by the presence of characteristic axial palatal plica inside the constriction, the orange shell color throughout the whorls, the absence of apical septum, and the constriction followed by a rather prominent swelling of whorl. Initial teleoconch with low and closely spaced ribs, which persists for 1/3–1/2 whorls, is also diagnostic of this species. Whereas, in other species, initial teleoconchs with low and closely spaced ribs are much shorter (less than 1/4 whorls), or the initial ribs are widely spaced. H. lamellata occurs sympatrically with H. alata and H. pteropurpuroides . For the morphological differences from the sympatric relatives, see the remarks on these species.

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 6. Terminology used in this study. (A) Shell dimensions. Abbreviations: D, shell diameter; H, shell height; PH, peristome height; SW, suture width. (B) An example showing the axial protrusions of shell wall along the axial ribs. Umbilical view of a shell of Hungerfordia pyramis (Crosse, 1866), only the last whorl shown. (C) Apical septa of some Hungerfordia species: (C1) apical whorls of a shell (live condition) of H. pteropurpuroides sp. nov.; (C2) apical whorls of a partially opened shell of H. alata (Crosse, 1866), which shows construction of an internal septum; (C3) subapical view of a shell of H. triplochilus sp. nov. after removal of the empty apical whorls above the septum.

FIGURE 7. Male soft parts of Palaina (Eupalaina) and Hungerfordia species. (A1, A2) P. (E.) patula Crosse, 1866, B0753; (B) P. (E.) sp.-20, live condition, B0732; (C) H. inflatula (Crosse, 1866), B0217; (D) H. pelewensis Beddome, 1889, live condition, B0651; (E) H. polymorpha (Crosse, 1866), live condition, B0659. Arrow heads indicate penes. Scale bars, 1mm. All specimens, UMUTZ-MG.

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 21. Hungerfordia lamellata (Crosse, 1866). (A1–A4) Loc. Ub3-1, B0199a; (B) sculpture on penultimate whorl, Loc. Ub3-1, B0199a; (C) axial ribs above the aperture, Loc. Ko8-2, B1419; (D1) inner surface of constriction (apical view), Loc. Ub3-1, B0199b; (D2) inner surface of constriction (apical view), Loc. BA4-1, B0282a; (E) sculpture on apical whorls, Loc. BA4-1, B0282b; (F1–F4) Loc. Ub3-1, B0199; (G1–G3) Loc. BA4-1, B0282b–c; (H) Loc. Ko2-2, B0059a; (I, J) Loc. Ko5-6, B0541; (K1) columella (dorsal view), Loc. Ub3-1, B0199c; (K2) columellar tooth (dorsal view), Loc. Ko2-2, B0059b; (L1, L2) outer surface, and (L3, L4) inner surface of operculum, Loc. Ub3-1, B0199. Arrow head shows position of the constriction. Scale bars, 1mm (A–C, F–K), 0.5 mm (D–E, L). All specimens, UMUTZ-MG.

FIGURE 22. Hungerfordia lamellata (Crosse, 1866). (A1–A6) Syntype of “Palaina” lamellata, MNHN 26604; (A7) sculpture on apical whorls of the syntype; (B1, B2) original labels of the syntype; (C) a fresh specimen with circum-apertural sculpture similar to the syntype, Loc. Ko5-6, UMUTZ-MG-B0541. Arrow head shows an abrupt whorl swelling after the constriction. Scale bars, 1mm.

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.