PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Acila (Truncacila) demessa

Bivalvia - Nuculida - Nuculidae

Taxonomy

Acila demessa was named by Finlay (1927) [DISTRIBUTION: Cretaceous; California.]. It is not a trace fossil.

It was recombined as Acila (Truncacila) demessa by Schenck (1936), Squires and Saul (2006).

Sister species lacking formal opinion data

A. asachiensis, A. ashiyaensis, A. cobboldiae, A. elongata, A. gettisburgensis, A. insignis, A. kusiroensis, A. minima, A. mirabilis, A. parva, A. picturata, A. piura, A. pusilla, A. schumardi, A. tosaensis, A. trilineata, A. elongata, A. antefultoni, A. elongata, A. isthmica, A. kovatschensis, A. submariabilis, A. vengeriana, A. nakazimai, A. chausiensis, A. chicotana, A. enpirensis, A. ermani, A. eximia, A. gottschei, A. granulata, A. himenourensis, A. ilpinensis, A. incignis, A. insignis, A. isignis, A. longa, A. marujamensis, A. munda, A. nakazimai, A. nehalemensis, A. nehalemensis, A. oyamadensis, A. pecticostata, A. picturata, A. plana, A. pleschakovi, A. praevigilia, A. schomburgki, A. triangula, A. vereshagini, Truncacila korjakensis, Truncacila munda, Truncacila shimojimensis, Truncacila subdemessa, Truncacila yoshidai

Synonyms

Nucula truncata was named by Gabb (1864) [DISTRIBUTION: Pleistocene-Recent; western Atlantic.]. It is extant.

It was recombined as Nucula (Acila) truncata by Gabb (1869); it was replaced with Acila demessa by Finlay (1927).

Synonymy list

Year	Name and author
1864	Nucula truncata Gabb p. 198 figs. PI. 26, Fig. 184, and 184 a, b
1869	Nucula (Acila) truncata Gabb p. 197
1894	Nucula truncata Turner p. 460
1927	Acila demessa Finlay p. 522
1930	Acila demessa Stewart p. 46 figs. Plate 3, fig. 6
1936	Acila (Truncacila) demessa Schenck p. 48
2006	Acila (Truncacila) demessa Squires and Saul p. 93

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Protostomia
—	Spiralia
superphylum	Lophotrochozoa
phylum	Mollusca
class	Bivalvia
—	Eubivalvia

Rank	Name	Author
subclass	Protobranchia	(Pelseneer 1889)
superorder	Nuculiformii	Dall 1889
order	Nuculida	(Dall 1889)
superfamily	Nuculoidea	(Gray 1824)
family	Nuculidae	Gray 1824
genus	Acila	Adams and Adams 1858
subgenus	Truncacila	Grant and Gale 1931
species	demessa	(Finlay 1927)

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.

†Acila (Truncacila) demessa Finlay 1927

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Invalid names: Nucula truncata Gabb 1864 [replaced]

Diagnosis

No diagnoses are available

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: Aberhan et al. 2004, Mikkelsen and Bieler 2008

Age range: base of the Coniacian to the top of the Maastrichtian or 89.80000 to 66.00000 Ma

Collections (44 total)

Time interval	Ma	Country or state	Original ID and collection number
Coniacian	89.8 - 85.7	USA (California)	Acila demessa (44214) Acila demessa, Nucula truncata (44232)
Early/Lower Santonian	85.7 - 83.6	USA (California)	Acila demessa (86956)
Santonian	85.7 - 83.6	USA (California)	Acila demessa (185391)
Campanian	83.6 - 72.2	USA (California)	Acila demessa (80945 80946 168012)
Early/Lower Campanian	83.6 - 72.2	USA (California)	Acila demessa (44274 44277 86786 176365) Nucula truncata (239772)
Late/Upper Campanian	83.6 - 72.2	USA (California)	Acila demessa (1513 1515 1547 72057 86793 86794 167703 167704 167705 185168 221105)
Middle Campanian	83.6 - 72.2	USA (California)	Acila demessa (144763 144773 185174 220908 220910 220911 220912 220916 221106 221107) Acila truncata (193033) Nucula truncata (72056)
Late/Upper Campanian - Early/Lower Maastrichtian	83.6 - 66.0	USA (California)	Acila demessa (44268)
Early/Lower Maastrichtian	72.2 - 66.0	USA (California)	Acila demessa (1545 83789 224893 225632)
Maastrichtian	72.2 - 66.0	Mexico	Truncacila demessa (1372)
Maastrichtian	72.2 - 66.0	USA (California)	Acila demessa (86853) Truncacila demessa (1354)
Maastrichtian	72.2 - 66.0	Mexico (Baja California)	Acila truncata (158099)