Duplipecten waihaoensis (Suter, 1917)
SUTER, H. 1917. Descriptions of new Tertiary Mollusca occurring in New Zealand, accompanied by a few notes on necessary changes in nomenclature. Part I. New Zealand Geological Survey, Paleontological Bulletin, 5: 1-93, pls. 1-13. [p. 69, pl. 7, figs. 15, 16 ]
1917 Pecten (Pseudamusium) [sic] waihaoensis Suter, 1917
H. Suter, 1917, plate 7.
|
«Shell moderately large and solid, valves not much inflated, equilateral, slightly oblique, the sculpture discrepant on the two valves, the light valve smooth, the left with distant flattish radial ribs. Beaks small, sharply pointed. Ears large, narrowly triangular, the anterior longer than the others. Anterior and posterior ends semicircular, the dorsal margin slightly concave, and slowly descending. Sculpture: Right valve almost smooth, shining, with very fine concentric striation; left valve with 12 to 14 distant radial ribs, rounded near the apex, but flattish and much depressed towards the basal margin, the interstices of about the same width or a little wider, and containing traces of an intermediate radial rib; the whole disc with fine concentric striae; ears transversely striated, the anterior ear with an indication of a median radial rib. Margins smooth inside. Hinge-plate broadly triangular, with a median triangular resilifer: the cardinal crura are inconspicuous, but the auricular crura are well developed. Adductor-scar large, rounded, above and slightly behind the centre.
Height, 58 mm.; length, 63 mm.; diameter of single valve, 10 mm. (holotype). Holotype in the collection of the New Zealand Geological Survey Loc.— Waihao greensands, Waihao Downs, South Canterbury: J. A. Thomson, 1913. Loc. No. 479 = Marly greensand, Waihao River: McKay, 1880. A right valve was also collected al Mount Harris, in the same district, bv Professor P. Marshall.— Miocene. Remark.— The right valve of this species is very similar to that of Pecten (Pseudamusium) huttonii (Park), but the latter is quite smooth, showing fine regular concentric striation only under the lens. The disc of waihiaoensis is much more prominently and somewhat irregularly concentrically striated, and near the beak there are traces of radial costae.»
HENRY SUTER, 1917
|
«PI. 5 d. Duplipecten waihaoensis (Suter, 1917) [Pecten (Pseudamusium) [sic] waihaoensis Suter 1917, p. 69; Lentipecten (Duplipecten) waihaoensis]. Type species of Duplipecten Marwick, 1928 (Pectinidae).
Size moderate for family (height 50-60 mm), right valve more inflated than left; anterior and posterior gapes well developed. Ears prominent, those on left valve having colinear dorsal margins, and separated from disc by shallow grooves; those on right valve with divergent dorsal margins (finely serrate on well preserved shells) and separated from disc by broad channels which dip below dorsal margins of disc distally. Byssal notch well developed; ne ctenolium. Sculpture on right valve of fine growth lines and faint radial striae; left valve with growth lines and weak radial striae in some shells, others with 12-14 broad, low, flattened costae becoming obsolete distally; interspaces as broad as costae, some with a weak radial cord appearing during growth.
Bortonian, Waihao Greensand, South Branch, Waihao River near Waihao Downs (type) (locally common).
Pectens conforming to the above diagnosis (i.e. including individuals with well developed radial costae in the left valve) are present in the middle part of the Waihao Greensand in the Waihao Downs section. Higher in the section, particularly in a pecten-rich bed near the top of the Bortonian, occur pectens identical in most respects to D. waihaoensis but having the left valve devoid of radial sculpture other than weak striae. These are assigned to D. parki, which is recorded from several Bortonian and Kaiatan localities in North Otago (type locality, Hampden Beach), South Canterbury, Westland and Chatham Island. Although originally assigned to Lentipecten (sensu stricto), D. parki is very similar to D. waihaoensis and the two species probably have an ancestor-descendant relationship, with D. parki replacing the latter species in the late Bortonian. Duplipecten was originally classed as a subgenus of Lentipecten, but the type species differ in a number of important shell characters that indicate they are not closely related. Loss of radial sculpture has occurred in many groups of pectens and is not in itself a reliable guide to phyletic relationships in the family. Figured specimen (PI. 5d): GS9886, J40/f8823, abandoned railway cutting, Waihao Downs, Bortonian (NZGS) x 1.» BEU, A. G. & P. A. MAXWELL. 1990. Cenozoic Mollusca of New Zealand. New Zealand Geological Survey Paleontological Bulletin, 58: 1-518, pls. 1-57. [p. 100, 101]
|
Duplipecten waihaoensis (Suter); A. G. Beu & P. A. Maxwell, 1990, Cenozoic Mollusca of New Zealand, plate 5, figure d.
|