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Acila (Truncacila) decisa

Bivalvia - Nuculida - Nuculidae

Taxonomy
Nucula decisa was named by Conrad (1855). Its type specimen is UCMP 31132 (neotype) and is a 3D body fossil.

It was recombined as Acila (Truncacila) decisa by Turner (1938), Moore (1983), Squires (1984), Squires (1987), Squires (1988), Squires (1999).

Synonyms
Synonymy list
YearName and author
1855Nucula decisa Conrad pp. 11 - 12 figs. pi. 2, fig. 19
1916Acila gabbiana Dickerson p. 481 figs. pl. 36, fig. 1
1922Nucula (Acila) stillwaterensis Weaver and Van Winkle Palmer p. 6 figs. pl. 8, fig. 8
1927Acila lajollaensis Hanna p. 270 figs. pl. 25, figs. 1, 3, 5, 7-8, 12, 15.
1938Acila (Truncacila) decisa Turner p. 41
1983Acila (Truncacila) decisa Moore p. A10 figs. Plate 1, figure 14; plate 2, figures 1-3
1984Acila (Truncacila) decisa Squires p. 41 figs. Figure 10a
1987Acila (Truncacila) decisa Squires p. 54 fig. 86
1988Acila (Truncacila) decisa Squires p. 17 fig. 44
1999Acila (Truncacila) decisa Squires p. 22 figs. Figure 49

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RankNameAuthor
kingdomAnimalia()
—Bilateria
—EubilateriaAx 1987
—Protostomia
—Spiralia
superphylumLophotrochozoa
phylumMollusca
classBivalvia
—Eubivalvia
RankNameAuthor
subclassProtobranchia(Pelseneer 1889)
superorderNuculiformiiDall 1889
orderNuculida(Dall 1889)
superfamilyNuculoidea(Gray 1824)
familyNuculidaeGray 1824
genusAcilaAdams and Adams 1858
subgenusTruncacilaGrant and Gale 1931
speciesdecisa()

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

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Invalid names: Acila gabbiana Dickerson 1916 [synonym], Acila lajollaensis Hanna 1927 [synonym], Nucula (Acila) stillwaterensis Weaver and Van Winkle Palmer 1922 [synonym]
Diagnosis
ReferenceDiagnosis
C. E. Weaver and K. Van Winkle Palmer 1922 (Nucula (Acila) stillwaterensis)Shell small, rectangular in outline ; anterior dorsal margin
nearly straight, posterior ventral margin nearly straight, sloping to a broadly
rounded anterior end which approaches the dorsal margin with greater convexity ;
escutcheon impressed but not defined by an incised line ; central portion of the
area of the escutcheon raised, protruding slightly beyond the posterior margin;
surface ornamented with radiating ribs medium in strength; above the central
portion of the shell the divarication is single, below the mid-area the series of
divarication is comparatively wide, the duplication increasing ventrad forming
five sets along the ventral margin ; the area of divarication occupying the middle
third of the ventral portion of the shell ; lunule not defined ; surface with heavy,
impressed growth lines forming wide undulations on the surface of the shell.
Measurements
No measurements are available
Composition: aragonitef
Entire body: yesf
Adult length: 1.0 to < 10f
Adult width: 1.0 to < 10f
Adult height: 1.0 to < 10f
Thickness: thinf
Folds: nonef
Ribbing: minorf
Spines: nonef
Internal reinforcement: nonef
Ontogeny: accretionf
Environment: coastal, inner shelf, outer shelf, oceanicf
Locomotion: facultatively mobilef
Life habit: infaunalf
Diet: deposit feederf
Diet 2: suspension feederf
Vision: blindc
Created: 2008-11-15 10:09:53
Modified: 2009-08-18 20:13:53
Source: f = family, c = class
References: Mikkelsen and Bieler 2008, Aberhan et al. 2004

Age range: base of the Selandian to the top of the Priabonian or 61.66000 to 33.90000 Ma

Collections (58 total)


Time interval Ma Country or state Original ID and collection number
Danian - Thanetian66.0 - 56.0Russian Federation Acila decisa (49981)
Paleocene66.0 - 56.0USA (California) Acila decisa (11117) Nucula sp. (190778 190779) Nucula truncata (190771 190772 190800)
Selandian61.66 - 59.24USA (California) Acila sp. a (239691)
Thanetian59.24 - 56.0USA (California) Acila decisa (52612 52613 52615 52617 52618) Acila sp. a (204137 239711)
Ypresian56.0 - 48.07USA (California) Acila decisa (78722 193545 207305 207306 207308) Acila decisa, Acila gabbiana (122294) Acila gabbiana (122337 122339) Nucila gabbiana (52434)
Ypresian56.0 - 48.07USA (Oregon) Acila decisa (52266 52267 52272 200799 200800 200802 200803 200804)
Ypresian56.0 - 48.07USA (Washington) Acila decisa (5544 5546)
Ypresian - Lutetian56.0 - 41.03USA (Oregon) Acila decisa (37871)
Eocene56.0 - 33.9Russian Federation Acila decisa (50129)
Lutetian48.07 - 41.03USA (California) Acila decisa (5524 5532 5541 16712 178733 200853) Acila lajollaensis (200720)
Lutetian48.07 - 41.03USA (Oregon) Acila decisa (200895 201033)
Lutetian - Bartonian48.07 - 37.71USA (Washington) Acila decisa (43343 43346)
Lutetian - Bartonian48.07 - 37.71Russian Federation Acila decisa (50126)
Middle Eocene - Late/Upper Eocene48.07 - 33.9USA (Washington) Acila decisa (203152)
Middle Eocene - Late/Upper Eocene48.07 - 33.9USA (California) Acila decisa (37930) Acila gabbiana (239769)
Middle Eocene - Late/Upper Eocene48.07 - 33.9USA (Washigton) Acila decisa (203153 203154 203155 203156)
Bartonian41.03 - 37.71USA (Washington) Nucula stillwaterensis (200105)
Bartonian41.03 - 37.71USA (Oregon) Acila decisa (200863)
Priabonian37.71 - 33.9USA (Washington) Acila decisa (202067)