Fortipecten hallae (Dall, 1921)
Pecten (Fortipecten) hallae Dall; F. S. MacNeil, J. B. Mertie, Jr. & H. A. Pilsbry, 1943, Marine Invertebrate Faunas of the Buried Beaches near Nome, plate 12, figures 1, 2.
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«Right valve convex, heavy, subcircular, with subequal ears, hinge-line wide and straight, the ears sculptured with rather rude incremental lines; radial sculpture of the valve consisting of 17 or 18 low, rounded ribs with rather shallow narrower interspaces channeled only near the beak; the minor sculpture, if any existed, has been removed by abrasion but there are faint traces of fine radial striae in the interspaces; the hinge has a very large resiliary pit with a narrow ridge on each side of it; the adductor scar was large and the the margins of the valves was undulated by the external sculpture. Height of right valve, 120; width, 125; length of hinge-line, 70; (semi) diameter, 28 mm. U. S. Nat. Mus. Cat. No. 333042.
A fragment has a width of 147 mm. The nearest relative is perhaps the Pliocene P. cerrosensis Gabb, which has twenty-five much stronger ribs with much narrower interspaces, and a less inflated and smaller shell.» WILLIAM HEALEY DALL, 1921
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«Disscussion.— The only available figures of this species (MacNeil and others, 1943) show the exteriors of two right valves and a left valve. The muscle scar is extremely large, and the shell has a thick subumbonal callus. The left valve is swollen both medially and along the dorsal margins, leaving shallow, broad, but distinct sulci both anterior and posterior of the medial area; it resembles Pecten (Pecten) in this respect. The shell is thick and it weathers soft and chalky with a silklike sheen. The left valve has fine radial riblets between the primary ribs and the surface retains remnants of a metal lathelike microsculpture.
Fortipecten hallae is most closely related to F. kenyoshiensis (Chinzei) from the middle Pliocene of Japan. The left valve of F. kenyoshiensis is very similar, both in gross features and in the texture of its interstitial riblets (see Chinzei, 1960, p. 66, fig. 2). The right valve of F. kenyoshiensis has narrower and more prominent ribs and may be more inflated, and these characteristics make it intermediate between P. hallae and F. takahashii. The inclusion of F. hallae in the fauna of the socalled Submarine Beach at Nome and in a similar fauna at Kivalina, north of Kotzbue Sound, is open to some question. Until the summer of 1961, when an old mine dump near the Solomon River was rediscovered, the exact locality of P. hallae was not known. Unfortunately, only a few unidentifiable scraps of other mollusks were found to occur with it, although P. hallae itself seems to have been fairly abundant. Not even fragments of P. hallae have been found in the Submarine Beach at Nome. The possibility certainly exists that the beds on Solomon River are a pre-Submarine Beach deposit not represented at Nome. A nearly complete but highly polished left valve of F. hallae from Kivalina, now in the California Academy of Sciences, and fragments of the species in Geological Survey collections apparently came from fossiliferous beds now exposed, but they have a preservation different from that of the rest of the fauna, and they could have been reworked into the beds now containing them from a submarine deposit. Until this species can be shown with certainty to have lived in the Submarine Beach, I am inclined to regard its inclusion in the fauna of the Submarine Reach as tentative. Types: The lectotype (USNM 499059), a right valve labeled the type of P. hallae, has a height of 120 mm and a length of 126 mm. A left valve (USNM 499061) labeled P. rhytidus is the best preserved known specimen. Type locality: Immediately above bedrock and about 20 ft below sea level in a prospect mine shaft, 0.8 mile east of Solomon townsite, and about 1 mile inland on the delta of the 'Solomon River, USGS 9250, M1267. Other occurrences: Small valley on north side of Kivalina River about 1.3 miles above its mouth on Kivalina Lagoon and about 5.3 miles north-northwest of Kivalina Village, Alaska, USGS M1817.» MACNEIL, F. S. 1967. Cenozoic pectinids of Alaska, Iceland, and other nothern regions. United States Geological Survey Professional Paper, 553: iv + 1-57, pls. 1-25. [p. 44]
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«The two valves of this, species, which were described not only as different species but, were placed in different subgenera, have never been figured. Consequently Grant and Gale, who had only the descriptions to go by, were misled as to the identity of the forms and placed them in two other different subgenera.
Pecten hallae, is closely related to the type of the subgenus Fortipecten Yabe and Hatai, Pecten takahashii Yokoyama (1940, p. 149, pI. 34, figs. 1-9, pI. 35, figs. 1-9.) from the lower and middle Pliocene of Japan, and together they comprise the known species of Fortipecten. The Alaskan species differs from the japanese species in being slightly less inflated and in havIng broader ribs, those of the right valve of P. hallae being wider than the interspaces, whereas in P. takahashii the ribs of the right valve are definitely narrower than the interspaces. Less contrast exists between the width of the ribs on the left valves. In spite of the differences pointed out, however, the similarity of the two forms is striking. Both are very heavy shells with large adductor scars. Dall in his description of P. hallae and P. rhytidus stated that no microsculpture is visible, but of two lef valves (rhytidus) labelled "type," the smaller and better preserved specimen retains in spots a fine sculpture in which successive lamellae are crinkled, with the crinkles of adjacent rows offset, the whole resembling the surface of metal plaster lath. This specimen is here figured, although the larger labelled specimen, the specimen whose dimensions were given in the original description, should probably be regarded as the type of rhytidus. Pecten takahashii has been determined by Japanese geologists to occur in beds believed to be lower and middle Pliocene. It is not apparent at present whether the species difference between the Alaskan and Japanese species is mainly a function of geographic separation or of actual time difference, but it is doubtful if the oldest of the beaches are as old as lower Pliocene. Probably all are late Pliocene, with a possibility that the youngest is early Pleistocene. Lectotype (a right valve, the labelled type: of P. hallae Dall, U. S. Nat. Mus. 499059) measures: height, 120.0 mm.; width, 126.0 mm.; convexity, 28.0 mm. The largest specimen, an incomplete valve, has width of more than 145 mm. Figured paratypes are U. S. Nat. Mus. 499060, 499061. The original number 333042 assigned to all the type material of P. hallae now refers only to right valve paratypes exclusive of the figured paratypes. Left valve paratypes (P. rhytidus), exclusive of the figured paratype, bear the number 333044. Occurrence.— "Buried Pliocene beach, 20 feet below surface, near Solomon River. Collector, Otto Halla." The exact beach is not known, but according to Doctor P. S. Smith, Chief Alaskan Geologist of the Geological Survey, Otto Halla was a mining man who operated mainly near Nome on the Submarine Beaches. Locality 9250.» MACNEIL, F. S., J. B. MERTIE, Jr. & H. A. PILSBRY. 1943. Marine Invertebrate Faunas of the Buried Beaches near Nome, Alaska. Journal of Paleontology. 17 (1): 69-96, pls. 10-16.
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Pecten (Fortipecten) hallae Dall; F. S. MacNeil, J. B. Mertie, Jr. & H. A. Pilsbry, 1943, Marine Invertebrate Faunas of the Buried Beaches near Nome, plate 13, figure 1.
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«Pecten (Plagioctenium) hallae Dall, Nautilus, Vol. 34, p. 76, 1921.
Type specimen: No. 33,042 in the U. S. National Museum. Pliocene ?: Nome, Alaska. This species has not been figured, and the description alone is not sufficient to show its relationships. Apparently it has a right valve like that of P. gibbus var. circularis (or aequisulcatus), but it is much larger (altitude 120 mm. or more).» GRANT, U. S. IV & H. R. GALE. 1931. Catalogue of the marine Pliocene and Pleistocene Mollusca of California and adjacent regions. Memoirs of the San Diego Society of Natural History, Volume 1, 1036 pp., pls. 1-32, 15 text figs. [p. 220]
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