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Tessarolax retusa

Gastropoda - Aporrhaidae

Taxonomy
Tessarolax retusa was named by Sowerby (1836).

It was recombined as Trilemma retusum by Blagovetshenskiy and Shumilkin (2006).

Sister species lacking formal opinion data

Synonymy list
YearName and author
1836Tessarolax retusa Sowerby
2006Trilemma retusum Blagovetshenskiy and Shumilkin p. 39
2015Tessarolax retusa Saul and Squires p. 43

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Protostomia
Spiralia
superphylumLophotrochozoa
phylumMollusca
classGastropoda
subclassCaenogastropoda(Cox 1959)
RankNameAuthor
Sorbeoconcha(Ponder and Lindberg 1997)
Hypsogastropoda(Ponder and Lindberg 1997)
superorderLatrogastropodaRiedel 2000
superfamilyStromboidea(Rafinesque 1815)
familyAporrhaidaeGray 1850
subfamilyAporrhainaeGray 1850
genusTessarolax
speciesretusaSowerby 1836

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.

Tessarolax retusa Sowerby 1836
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Diagnosis
ReferenceDiagnosis
L. R. Saul and R. L. Squires 2015Blagovetshenskiy and Shumilkin (2006:39) placed Tessarolax retusa (J. de Sowerby in Fitton) in genus Trilemma Blagovetshenskiy and Shumilkin, 2006. Tessarolax differs from Trilemma, however, by having much narrower digitations without a winglike "membrane" between the outer lip digitations and having a longer apical digitation that also hugs the spire and extends beyond it. Although Blagovetshenskiy and Shumilkin (2006) characterized Tessarolax as having a projection on the side of the shell opposite to the wing-like extension of the outer lip, this projection (referred to herein as the fictavarix) is actually not truly opposite the outer lip. The fictavarix on Tessarolax leans "forward" so that its outer margin and the forward bending of the outer lip rest on the substrate. In summary, Tessarolax retusa does not have the tall, wide spire or the wing-like extension of the outer lip bearing two broad digitations, especially the anterior outer lip digitation, that characterize Trilemma.