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Journal of Paleontology 90(1):31–42
Wangaluta henaconstricta new genus new species Figure 6A–6C, 6G
Diagnosis.—Same as for genus.
Description.—Shell medium-sized for family (49.5mm high), moderately robust, fusiform; spire moderately high, of at least four subtrapezoid, medially concave whorls; length of aperture slightly longer than height of spire; whorl inflation moderately rapid from penultimate to last whorl; spire angle approximately 43°; protoconch unknown, but probably large and bulbous; sutures moderately clasping, wrapped around succeeding whorls mostly concealing axially extending ribs; last whorl slightly to moderately inflated, elongate; last whorl with adapi- cal, subsutural, convex, swollen band or welt (5.0mm wide), bordered abapically by moderately strong constriction; last whorl with steep convex slope; basal constriction moderately rapid to very rapid, drawn abapically to moderately strong neck; sculpture on last whorl of moderately strong growth lines, faint spiral threads, adapically near future and disappearing abapi- cally, and 14 strong, raised, broad, rounded, axially extending ribs that originate at suture where they are slightly more sub- dued, fade at adapical constriction, reappear at last whorl per- iphery where they are robust and fade and disappear midway down basal constriction; axials widely separated at approxi- mately 2.0mm intervals, interspaces smooth; penultimate and older whorls also with 14 axial ribs confined mostly to abapical third of whorl where they are strongest and adapical third where they are weakest subsuturally, fading centrally at whorl con- striction; on teleoconch whorls axials are parallel to subparallel to each other; spire whorls with approximately 25 wavy spiral threads; growth lines broadly sinused with apex located cen- trally on last whorl at onset of pronounced axials, more sub- prosocline subsuturally and adapically and slightly sinused abapically at onset of basal constriction; growth lines cross axials obliquely on adapical portion of last whorl and then fol- low axials on central and abapical portion; aperture elongate, narrow, siphonostomatous; siphonal canal moderately long to long for family, slightly twisted to the left with feebly developed or obsolete notch; fasciole poorly developed; labium with moderately broad, relatively thin inductura, broadening slightly in the parietal region; columella slightly concave bearing three spaced, oblique plaits centrally, medial plait strongest of the three; outer lip moderately thin.
Dimensions.—Holotype OU 41227 height 49.5mm, probably approximately 55.0mm if complete, diameter of last whorl 21.0mm.
Type.—Holotype OU 41227.
Type locality.—Mitchells Rocks, Wangaloa, southeastern Otago, South Island, H46/f166A. Figured specimen.—OU 41227. Material.—Holotype.
Stratigraphic range.—Wangaloa Formation, ‘Wangaloan’ Stage = lower part of the Teurian Stage, mid-Danian, early Paleocene, P. golzowense Zone,Wilson (1992b), approximately 64–62Ma.
Geographic distribution.—Wangaloa, Southeastern Otago.
Discussion.—Wangaluta henaconstricta n. gen. n. sp. is known from the beautifully preserved holotype from Mitchells Rocks, Wangaloa. Affinities of W. henaconstricta n. gen. n. sp. are unclear, but a close relationshipwithPaleopsephaea neozealanica Finlay andMarwick, 1937 (pp. 80–81, pl. 11, fig. 6–7; Fleming, 1966, p. 328, pl. 115, figs. 1409–1411), seems probable.Disparity of the number of columellar plaits, growth lines and sculpture of W. henaconstricta and P. neozelanica hinders comparisons of this species with other forms.Wangaluta henaconstricta n. gen. n. sp. has very strong axially extended ribs, smaller abapical ribs on the penultimate whorl, spiral sculpture of threads, stronger more prosocline growth lines on the swollen subsutural band and three developed columellar plaits, compared to P. neozelanica,which has no to feebly developed axial sculpture on the last whorl, large broad axial ribs on the abapical third of the penultimate whorl, more orthocline growth lines and a well-developed oblique fold on the columella and a second, slightly higher and feebly developed fold. Voluta elongata d’Orbigny, 1842 (pp. 323–324, pl. 220,
fig. 3 (not fig. 2 as stated in the text by d’Orbigny); Stoliczka, 1867, pp. 87–89, pl. 7, figs. 1–9, especially fig. 3 (reassigned to Fulgararia pro Fulgoraria), an inferred variable species from the Late Cretaceous of France and southern India, is reminiscent of the Danian Wangaloa Formation species in outline and sculpture, but has a slower and more constant basal constriction, a less swollen subsutural welt, more axially extending ribs and a much stronger spiral sculpture. Probably not all of the figures of shells on plate 7, attributed to Fulguraria elongata by Stoliczka, are conspecific, as considered by him. Other superficially similar, but probably unrelated
species, include the Neogene New Zealand species Alcithoe (Leporemax) gatesi Marwick, 1926a (p. 302, pl. 70, fig. 7; Fleming, 1966, p. 356, pl. 129, fig. 1504; Beu and Maxwell, 1990, pp. 300–301, pl. 37, fig. o) and the Recent rare Chinese species Fulgoraria s.s. leviscula Rehder, 1969 (see discussion and figures by Weaver and du Pont, 1970, p. 35, pl. 10, figs. C–D), but these species compared to W. henaconstricta n. gen. n. sp. lack the distinctive subsutural band, have more columellar plaits, display differences in sculpture, have distinct siphonal canals and have a slower basal constriction. Authoritative works on Volutidae such as Marwick
(1926a), Smith (1942), Wenz (1943), Sohl (1964), Weaver and du Pont (1970), Darragh (1988), and Oleinick (1993), and on ptychatrachine turbinellid gastropods including Harasewych (1987), assist little in identifying the affinities of Wangaluta henaconstricta n. gen. n. sp., which appears to have been a short-lived and very rare taxon. It is quite probable that W. henaconstricta n. gen. n. sp., along with Alcithoe s.l. wangaloaensis n. sp., described below, may have been brought into shallower shelf setting from a slightly deeper environment as reflected by both species’ rarity either by storm even or by Decapoda and the like. This scenario is speculative as the
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