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

Isfarispira perlata

Gastropoda - Euomphalina - Anomphalidae

Taxonomy
Pleurotomaria perlata was named by Hall (1852). It is not extant.

It was recombined as Isfarispira perlata by Peel (2018).

Synonymy list
YearName and author
1852Pleurotomaria perlata Hall
2018Isfarispira perlata Peel figs. 1A-H

Is something missing? Join the Paleobiology Database and enter the data

RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Protostomia
Spiralia
superphylumLophotrochozoa
phylumMollusca
classGastropoda
RankNameAuthor
subclassEogastropoda
orderEuomphalina
superfamilyEuomphaloidea()
familyAnomphalidae
subfamilyPycnomphalinae
genusIsfarispira
speciesperlata()

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.

Isfarispira perlata Hall 1852
show all | hide all
Diagnosis
ReferenceDiagnosis
J. S. Peel 2018A species of Isfarispira with lenticular, discoidal, form, height about one third of maximum width, and acutely angular periphery. About eight, possibly ten whorls are present, with the sides of the spire almost flat; incremental angle about 130°. Basal surface shallowly convex, inclined, between the periphery and the umbilicus which is about one quarter of the shell diameter. Umbilical wall (Fig. 1E, arrow uw) short, flat and parallel to the axis of coiling, forming a right angle to the basal surface. A blade-like flange (Fig. 1C and E, arrow uw) extends adaxially as a continuation of the basal surface almost completely closing the umbilicus. In apical view, the narrow outer whorl face (Fig. 1C, owf) is flattened between only slightly incised sutures and has a similar width, measured radially, to the parietal wall (Fig. 1C, pw). Thus, in apical view (Fig. 1A and C) the whorls appear narrow and expand at a rate of about 1.1, measured along a radius as the ratio of the linear distance between successive sutures. In cross-section, the height of the whorl varies between one third and almost half its maximum width.

The shell aperture is known from the fine growth lines on the whorl surfaces. It is radial with a shallow emargination at the periphery. Growth lines on the upper whorl surface are shallowly prosocline and slightly oblique to the preceding suture (Fig. 1A and D). Growth lines on the basal surface are also prosocline, initially perpendicular to the umbilical shoulder before curving backwards towards the periphery (Fig. 1F and H). A slit and resultant selenizone are seemingly not present. Fine discontinuous spiral striations may occur on the upper whorl surface (Fig. 1D and H, arrows).

Shell interior septate; shell wall thin.