Ruthipecten tuftsensis (Turner, 1967)
TURNER, R. D. 1967. A new species of fossil Chlamys from Wright Valley McMurdo Sound, Antarctica. New Zealand Journal of Geology & Geophysics, 10: 446-454. [p. 450, figs. 3-5]
1967 Chlamys (Zygochlamys) tuftsensis Turner, 1967
R. D. Turner, 1967, figures 3, 4.
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«This species is named in honour of Tufts University, Medford, Massachusetts, where Professor R. Nichols teaches.
MATERIAL: Hundreds of fragments and 5 complete valves (2 right and 3 left) were found in glacio-fluvial gravels in Wright Valley. The curvature and size of the fragments indicate that many of the specimens were much larger than the measurement given for the complet valves. DESCRIPTION: Valves solid, mederately inflated, and nearly circular in outline, being only slightly higher than long. Hinge line straight; anterior ears nearly twice as long as the posterior ones. Beak angle about 90º. Radial sculpture consisting in 5-7 broad, low, slightly nodulose primary ribs between each of wich there are from 3 to 6 narrower ribs. The secondary ribs are produced both by intercalation and gemination and vary in strength, some being nearly as strong as the primary ribs, through others are almost thread-like. At the ventral margin there may be from 25 to 30 ribs. The concentric sculpture consist of slightly imbricate, incremental lamellae. Posteior ears of both valves nearly right angled. Anterior ear on left valve aproximately right angled. Anterior ear of right valve elongate, with a shallow but well defined byssal notch and ctenolium with 4 or 5 weak but distinct teeth. Ears sculptured with 4-6 faint radial ribs and incremental lamellae. Ligament area narrow, resilial pit trigonal. MEASUREMENTS
TYPES: Holotype MCZ 256085, a right valve; and paratypes MCZ 256086, 4 valves plus many fragments, from outwash gravel near Bull Pass, Wright Valley, McMurdo Sound, Antarctica (approx. 77º 30' S; 162º E) at about 1,000 ft (305 m) elevation. Paratypes from the same locality consisting of nearly complete valve plus fragments are in the World Mollusca Collection of the New Zealand Geological Survey no. WM 8457.
AGE: Early to middle Pleistocene (See p. 448.) REMARKS: Dr C. A., Fleming and I. G. Speden are both recognised authorities on the fossils from this area and I am grateful for their opinions concerning the relationships of tuftsensis. Fleming (pers. com., 1961) wrote: "Speden agrees with me that the Wright Valley Chlamys shows resemblances to C. anderssoni alone of the known Antarctic pectenids" and further that "as anderssoni is remarkably constant from Graham Land to McMurdo, it seems probably the Wright Valley shells are of somewhat different age." Chlamys (Zygochlamys) tuftsensis differs from anderssoni in having more convex valves, in having only a few primary ribs which are interspaced with secondary ones of varying strength, and in having less pronounced imbricate concentric lamellae. The difference between the primary and secondary ribs is even more marked than in geminata as described by Ortmann (1902). The byssal notch and ctenolium is similar to that of both anderssoni and geminata. Superficially anderssoni and tuftsensis appear quite different but it is evident that they are related and both probably stemmed from geminata, perhaps independently. They both have been found in the vicinity of McMurdo Sound, but in different Pleisocene glacial deposits.» RUTH DIXON TURNER, 1967
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«Beu & Taviani (2014) figured several of the specimens illustrated here and, in their description, provided information to suggest a specific difference between Sørsdal Formation specimens and R. tuftsensis from the type locality. Jonkers (2003) figured a specimen from Marine Plain and mentioned that costae in Marine Plain material are especially nodose.
Ruthipecten campestris sp. nov. is distinguished from R. tuftsensis in the character of the costae and the prominent nodes. As shown by Jonkers (2003, pl. 12, figs f–h) and Beu & Taviani (2014, fig. 5A), as commarginal growth lines cross costae in R. tuftsensis, the costae are affected to develop irregular surfaces. This is not the case in the new species where the growth lines appear to cross smoothly without causing such irregularities; this feature is apparent in the figured specimens (Fig. 12A, D) and on fragments, the limited sources of information on the shell surface. Ruthipecten campestris appears to be less inflated than R. tuftsensis. The nodes in R. campestris are best developed close to the distal end of costae around the margin..» QUILTY, P. G., T. A. DARRAGH, S. J. GALLAGHER & L. A. HARDING. 2016. Pliocene Mollusca (Bivalvia, Gastropoda) from the Sørsdal Formation, Marine Plain, Vestfold Hills, East Antarctica: taxonomy and implications for Antarctic Pliocene palaeoenvironments. Alcheringa: An Australasian Journal of Palaeontology, 40 (4): 556-582. [p. 16]
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Ruthipecten campestris Quilty, Darragh, Gallagher & Harding sp. nov.; P. G. Quilty, T. A. Darragh, S. J. Gallagher & L. A. Harding, 2016, Pliocene Mollusca (Bivalvia, Gastropoda) from the Sørsdal Formation, Marine Plain, Vestfold Hills, East Antarctica, figure 12A-12E.
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