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in which the primary veins originate at the base of the lamina and run out towards the margin. The leaves are unlobed and have five primary veins of which the basal pair are weakly developed, and have an estimated size of 7 centimetres (2.8 in) long by 5 centimetres (2.0 in) wide in overall
335:
aged, outcrop of the Beaver Creek flora. Although it was found north of the Ruby Flora, which outcrops in southeast
Montana, the similarities in overall floral composition between the Beaver Creek, Ruby, and other Montana floras are interpreted by Wolfe and Tanai to indicate that the assemblages are
409:
602:
663:
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361:, meaning a probable similar age for the Beaver Creek assemblage. The Beaver Creek assemblage was host to a total of six
658:
570:
254:
491:. This is based on the overall vein structure and small uniformly sized teeth, although it is the only
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428:
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for rill or brook, in recognition of the type and only location for the species at Beaver Creek.
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615:
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331:
is represented by a single fossil specimen that was recovered from a late Eocene, possibly
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158:
537:
Journal of the
Faculty of Science, Hokkaido University. Series 4, Geology and Mineralogy
643:
432:
145:
637:
420:
417:
393:
273:
67:
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in nature. The age of the Ruby flora is considered to range from approximately
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87:
52:
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are simple in structure and are generally ovate in shape, with perfectly
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314:, USA. It is one of several extinct species placed in the living section
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441:
Journal of the
Faculty of Science, Hokkaido University
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of the type specimen are currently preserved in the
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533:(maples) in the Cenozoic of Western North America"
458:", the genus name for beavers, and "rivularis",
410:University of California Museum of Paleontology
425:United States Geological Survey, Denver office
529:"Systematics, Phylogeny, and Distribution of
8:
522:
520:
518:
516:
514:
512:
565:
20:
508:
431:. Wolfe and Tanai published their 1987
400:leaf specimen UCMP 93l0A, B. Both the
392:The species was described from a lone
7:
543:(1): 23, 74, 75, 240, & plate 4.
310:sediments exposed in the state of
14:
306:. The species is known from the
119:
527:Wolfe, J.A.; Tanai, T. (1987).
454:is a combination of the words "
664:Extinct flora of North America
416:. The specimen was studied by
1:
654:Fossil taxa described in 1987
479:dimension. The morphology of
483:suggests placement into the
476:actinodromous vein structure
680:
408:collections housed at the
324:History and classification
299:described from a solitary
260:
253:
116:Scientific classification
114:
23:
649:Plants described in 1987
16:Extinct species of maple
427:and Toshimasa Tanai of
359: million years ago
352: million years ago
345: million years ago
246:A. castorrivularis
579:Acer castorrivularis
472:Acer castorrivularis
414:Berkeley, California
402:part and counterpart
329:Acer castorrivularis
285:Acer castorrivularis
267:Acer castorrivularis
25:Acer castorrivularis
429:Hokkaido University
495:member of section
481:A. castorrivularis
437:A. castorrivularis
367:A. castorrivularis
631:
630:
616:Open Tree of Life
571:Taxon identifiers
365:species in 1987:
347:to approximately
281:
280:
276:& Tanai, 1987
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624:
623:
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433:type description
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29:Temporal range:
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555:"perseus.tufts"
553:
552:
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499:to be unlobed.
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452:castorrivularis
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354:or as young as
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470:The leaves of
467:
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447:of the chosen
418:paleobotanists
406:paleobotanical
375:A. lincolnense
371:A. florissanti
325:
322:
295:in the family
288:is an extinct
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659:Eocene plants
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449:specific name
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422:
421:Jack A. Wolfe
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411:
407:
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394:type specimen
390:
388:
384:
383:A. salmonense
380:
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308:latest Eocene
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255:Binomial name
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146:Tracheophytes
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24:
18:
466:Description
387:A. tiffneyi
297:Sapindaceae
205:Sapindaceae
159:Angiosperms
35:38β34
31:Late Eocene
638:Categories
503:References
379:A. milleri
333:Chadronian
195:Sapindales
497:Macrantha
489:Macrantha
445:etymology
317:Macrantha
239:Species:
232:Macrantha
223:Section:
129:Kingdom:
594:Q4673148
588:Wikidata
493:Tertiary
487:section
398:holotype
201:Family:
172:Eudicots
621:7642043
608:8871282
439:in the
423:of the
312:Montana
293:species
264:†
243:†
211:Genus:
191:Order:
133:Plantae
104:↓
456:Castor
443:. The
396:, the
385:, and
338:coeval
301:fossil
185:Rosids
644:Maple
460:Latin
290:maple
274:Wolfe
230:sect.
228:Acer
179:Clade
166:Clade
153:Clade
140:Clade
603:GBIF
531:Acer
485:Acer
435:for
363:Acer
304:leaf
216:Acer
43:Preκ
412:in
640::
618::
605::
590::
541:22
539:.
535:.
511:^
389:.
381:,
377:,
373:,
369:,
357:32
350:34
343:38
320:.
181::
168::
155::
142::
93:Pg
37:Ma
557:.
98:N
88:K
83:J
78:T
73:P
68:C
63:D
58:S
53:O
48:κ
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