PBDB Taxon

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

Perisphinctes (Arisphinctes) trifidus

Cephalopoda - Ammonitida - Perisphinctidae

Taxonomy

Ammonites trifidus was named by Sowerby (1821).

It was recombined as Perisphinctes (Arisphinctes) trifidus by Pandey et al. (2012).

Sister species lacking formal opinion data

P. africanus, P. andium, P. mairei-matheyi, P. malinowskae, P. panderi, P. polygyratus, P. praestenocyclus, P. progeron, P. quadratus, P. scythicus, P. siemiradzkii, P. eucostatus, P. quadratus, P. pickeringius, P. buckmani, P. buckmanni, P. luciaeformis, P. crassissimus, P. A, P. B, P. anguiculus, P. patturatensis, P. siemirazkii, P. roedereri, P. alatus, P. andelotensis, P. densecostatus, P. pumilus, P. dorsoplanus, P. dacquei, P. polygyratus

Synonymy list

Year	Name and author
1821	Ammonites trifidus Sowerby p. 194 figs. Pls. 292, 293
2012	Perisphinctes (Arisphinctes) trifidus Pandey et al. p. 506 figs. Pl. XII, figs. 6, 7; Fig. 30; Tab. 17

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Protostomia
—	Spiralia
superphylum	Lophotrochozoa
phylum	Mollusca
class	Cephalopoda	Cuvier 1797
subclass	Ammonoidea	()

Rank	Name	Author
order	Ammonitida
suborder	Ammonitina	Hyatt 1889
superfamily	Perisphinctoidea	(Steinman 1890)
family	Perisphinctidae	Steinmann 1890
subfamily	Perisphinctinae	Steinmann 1890
genus	Perisphinctes	()
subgenus	Arisphinctes	(Buckman 1924)
species	trifidus	()

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.

†Perisphinctes (Arisphinctes) trifidus Sowerby 1821

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Diagnosis

Reference	Diagnosis
D.K. Pandey et al. 2012	Shells small, evolute, incomplete. Whorl section compressed and rounded to subrectangular (Fig. 30A, B). Feebly arched lanks merge into venter at obtusely rounded ventrolateral shoulder. Maximum thickness of whorl at one-third of lank height. Ornamentation consists of ine, isocostate, prorsiradiate primary ribs, bifurcating regularly at the ventrolateral shoulder (Fig. 30C). Secondaries cross the venter with slight forward-directed convexity. Four constrictions per whorl.

Measurements

No measurements are available

Composition:

aragoniteo

Environment:

marinec

Locomotion:

fast-movingo

Life habit:

nektonico

Diet:

carnivoreo

Vision:

well-developedc

Created:

2005-01-28 02:27:03

Modified:

2009-10-08 14:14:55

Source: o = order, c = class

References: Kiessling 2003, Kiessling 2004

Age range: Late/Upper Oxfordian or 161.20000 to 155.70000 Ma

Collections (3 total)

Time interval	Ma	Country or state	Original ID and collection number
Early/Lower Oxfordian	161.2 - 155.7	France	Perisphinctes trifidus (12286 12287)
Late/Upper Oxfordian	161.2 - 155.7	Madagascar (Atsimo-Andrefana)	Arisphinctes helenae (234238)