Towaipecten mariae (Finlay, 1927)
FINLAY, H. J. 1927. New specific names for Austral Mollusca. Transactions of the Royal Society of New Zealand, 57: 488-533. [p. 526]
«REMARKS: The close similarity of Towaipecten mariae to T. katieae in all characters other than the presence of plicae in T. mariae leaves little doubt of a very close phylogenetic relationship between these two. Beu (in Beu & Maxwell 1990, p. 309) was impressed by the similarity between the plicae of T. mariae and the square-edged major costae of the weakly sculptured end-members of the Sectipecten allani population in the Momoe-a-Toa Shellbed, near Cape Young, Chatham Islands (basal Opoitian; see Campbell et al. 1993, p. 117-120). Subsequent recognition of the Mangapanian presumed ancestor of T. mariae showed that the similarity fo Sectipecten allani is yet another confusing convergence.
DISTRIBUTION: Towaipecten mariae is common at only two localities, Scinde Island Limestone at Napier and Castlepoint Formation at Castlepoint, eastern Wairarapa. These are both of early Nukumaruan age. Specimens occur also in some numbers in limestone "member C" of Pukenui Limestone in Makara River, South Wairarapa, and were collected in some numbers (with equally common Z. delicatula) in Kumeroa Limestone in a temporary exposure at Ashcott Hill, Ruataniwha Plains (see Appendix A for localities). These last two localities are younger than the basal Nukumaruan zone of Phialopecten triphooki and T. mariae might well occur throughout the Nukumaruan Stage. Specimens occur in small numbers at several other localities as far south as Palliser Bay (Z. delicatula-Pelicaria rugosa sandstone at mouth of Whangaimoana Stream; Fig. 23a,d) but I am not aware of specimens from any locality outside eastem North Island. Perhaps the best representative sample of pectinids from the base of Scinde Island Limestone at Napier is to be seen on the pillars of the southern gates of Nelson Park, Napier, and there T. mariae is almost as common u P. triphooki. However, localities where either of these species can be collected in situ at, Napier depend on temporary excavations for building sites. AGE: Nukumaruan.» BEU, A. G. 1995. Pliocene Limestones and their scallops. Lithostratigraphy, pectinid biostratigraphy, and paleogeography of eastern North Island late Neogene limestone. Institute of Geological & Nuclear Sciences Monograph 10. Institute of Geological and Nuclear Sciences, Ltd., Lower Hutt, New Zealand, 243 p. [p. 51]
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Towaipecten mariae (Finlay); A. G. Beu, 1995, Pliocene Limestones and their scallops, figures 18a, c.
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«PI. 38 h, i. Sectipecten mariae (Finlay, 1927) [Pecten semiplicatus Hutton 1873b, p. 30 (not of Alth in Favre, 1869); Pallium mariae Finlay 1927b, p. 526 (new name for Pecten semiplicatus Hutton, preoccupied); Kaparachlamys mariae] (Pectinidae).
Large for family (80-100 mm high); length variable, from slightly greater than to slightly less than height; left valve markedly more inflated than right, but even left valve little inflated, right valve almost flat. Ears almost equal on the 2 valves, slightly asymmetrical; posterior margin of posterior ears sloping backward moderately, anterior margin of anterior ears sloping slightly backward, sinuous, with broad, shallow, byssal sinus but no ctenolium in right valve. Sculpture of 6 or 7 very low radial folds near umbo of both valves, lower and wider on right valve than on left, fading out by mid-height of large shells; superimposed on them are many low, wide, flat-topped, closely spaced radial costae on right valve (becoming obsolete before outer margin of large shells) and many low narrow relatively widely spaced radial costae on left valve (becoming low and wide before outer margin of large shells). Interior features not seen (all are either articulated shells, or in hard limestone). Waipipian ?; Mangapanian-Nukumaruan. Scinde Island Limestone, Napier, Hawke's Bay, early Nukumaruan (lectotype of Pecten semiplicatus; Boreham 1965, p. 27); the other syntype(s?) are from Castlepoint, west Wairarapa coast (also early Nukumaruan) where the species is common. Common also in limestone bed "C" of Pukenui Limestone (Nukumaruan) in Makara River, east of Martinborough, southern Wairarapa, and as common as Phialopecten triphooki in Te Aute Limestone (Mangapanian) at the summit of Towai Road, Puketoi Range, southern Hawke's Bay; widely distributed but uncommon in shallow-water shellbeds and coquina limestone in Hawke's Bay, Wairarapa, and North Canterbury. Sectipecten mariae was apparently a freelying, actively swimming species of hard-ground environments. Careful examination of the highly variable Momoe-a-Toa (northern Chatham Island) population of Sectipecten allani (PI. 33c) has shown that the narrowly costate endmembers of S. allani are distinguishable from S. mariae only by their slightly more prominent radial folds, and persistence of right-valve costae almost to the valve margin; the existence of marked finely and coarsely costate end-members in the Momoe-a-Toa population therefore appears to indicate that this is almost the only direct record in New Zealand Cenozoic rocks of a molluscan lineage branching event, and that S. mariae evolved from early S. allani. As noted above, S. allani appears to have become adapted to progressively more near-shore, high-energy environments through the Pliocene, whereas S. mariae appears to have, to some extent, occupied the niche of Late Miocene Sectipecten. The type species of Kaparachlamys, "Placopecten" hectori (Waipipian, Pitt I., Chatham Islands) lacks radial folds and has many, very uniform, fine radial costae on both valves, but agrees with K. mariae in having the left valve a little more inflated than the right, and in ear shape. It appears that S. mariae would be better referred to Sectipecten than to Kaparachlamys, leaving only K. hectori in Kaparachlamys. K. hectori closely resembles American Placopecten species, but the byssal notch is a little shallower in K. hectori than in Placopecten , so the close similarity of K. hectori to Placopecten may be superficial, but needs more study. Figured specimen (PI. 38h, i): GS5491, S28/f6594, Pelicaria rugosa-Chlamys patagonica delicatula beds at east side of mouth of Whangaimoana Stream, Palliser Bay, southern Wairarapa, early Nukumaruan (TM2922, NZGS) xl.» 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. 398]
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Sectipecten mariae (Finlay); A. G. Beu & P. A. Maxwell, 1990, Cenozoic Mollusca of New Zealand, plate 38, fihures h, i.
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«REDESCRIPTION (based on the lectotype and a few poorly preserved fragments and casts from Napier, GS 576, 702; Suter's figured specimen and several other specimens from Castle Point, GS 81, 1820; and the well preserved complete individual from Whangaimoana, GS 5491): Shell large, thin-walled, equilateral, subcircular in outline. Left valve more inflafed than right. Left valves usually only slightly inflated but one individual has a strongly, inflated left valve; right valves nearly flat. Ears subequal, with shallow byssal notch in young stages, obsolete in adults. Most valves folded round the apex into six or seven shallow radial plications, which die out towards the ventral margin; folding variable in strength, sometimes hardly evident. Sculpture of right valve: at the apex, about 45 to 60 narrow, low, smooth, flat-topped, subequal ribs, separated by linear grooves. Ribs widen and anastomose and finally die away altogether on the distal part of the disc at about 40-70 mm from the apex: Very fine, close, sharp, concentric ridges crowding the interstices and ribs except for the crests. Strong concentric, growth lines evident where radial sculpture obsolete. Sculpture of left valve: at the apex about 45 to 60 narrow threadlike riblets, rather higher and sharper than on right valve, with wider interstices. Fine, sharp, concentric ridges cover the whole disc including the rib-crests. Radial ribbing tends to become obsolete towards the ventral margin, but at a later stage than on the corresponding right valve, at about 60 mm or more from the apex. On both valves the number of ribs increases by the intercalation of secondary riblets and by the splitting of the primary ribs. On some specimens the 200 or more riblets so formed become separate and subequal in strength; on others they remain grouped, forming fewer, compound ribs. Ears sculptured by about six radial threads, strongest on the right anterior ear and in earliest growth stages, but otherwise nearly obsolete.
DIMENSIONS: Lectotype - height, 64 mm (estimated); length, 62 mm (estimated). Figured specimen from Whangaimoana (TM 2922) - height, 95 mm; length, 96 mm; inflation (two valves), 24 mm. The largest specimen collected, of which only the distal portion remains, must have measured over 120 mm in height (GS 1820, Castle Point).
Distinguished from Kaparachlamys hectori by having a heavier shell and coarser, more prominent, and more uneven radial ribbing. On some specimens of K. mariae the radial plications round the umbo are stronger than on K. hectori.»
BOREHAM, A. U. E. 1965. A revision of F. W. Hutton's pelecypod species described in the Catalogue of Tertiary Mollusca and Echinodermata. New Zealand Geological Survey Paleontological Bulletin, 37: 1-125, pls. 1-20. [p. 28]
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Kaparachlamys mariae (H. J. Finlay, 1927); A. U. E. Boreham, 1965, A revision of F. W. Hutton's pelecypod species described in the Catalogue of Tertiary Mollusca and Echinodermata, plate 6, figures 1, 2, 4.
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