''Euthema'' is a

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of minute

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...

s with an operculum,

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

s in the family

Diplommatinidae Diplommatinidae is a family (biology), family of small land snails, also known as staircase snails, with an operculum (gastropod), operculum, Terrestrial molluscs, terrestrial gastropod mollusks in the superfamily Cyclophoroidea. The Cochlostoma ...

from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Burmese and Hkamti ambers.

Species

As of 2021, 8 species are placed into ''Euthema'': *''E. annae'' : described from the

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The ...

, the species was first described in the paper published online by "

Cretaceous Research ''Cretaceous Research'' is a bimonthly peer-reviewed scientific journal published by Elsevier. The journal focuses on topics dealing with the Cretaceous period and the Cretaceous–Paleogene boundary. Abstracting and indexing The journal is abst ...

" on October 16th 2020, which qualifies as a nomenclatural act under Article 8.5 of the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

when registered in

ZooBank ZooBank is an open access website intended to be the official International Commission on Zoological Nomenclature (ICZN) registry of zoological nomenclature. Any nomenclatural acts (e.g. publications that create or change a taxonomic name) need t ...

, though the final version of the paper was published and printed in February 2021. *''E. dilatata'' , originally described as ''Truncatellina dilatatus'' *''E. hesoana'' *''E. lophopleura'' , originally described in the new genus ''Xenostoma'' *''E. myanmarica'' - species from

Hkamti amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The ...

*''E. naggsi'' , type species *''E. spelomphalos'' , originally described in the new genus ''Paleodiplommatina'' *''E. truncatellina'' ZooBank - ''Euthema truncatellina''
/ref>

Etymology

''Euthema truncatellina'' is named after the extant genus ''

Truncatellina ''Truncatellina'' is a genus of very small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Truncatellinidae.MolluscaBase (2018). Truncatellina R. T. Lowe, 1852. Accessed through: World Register of Marine Spec ...

'' (

Stylommatophora Stylommatophora is an orderPhilippe Bouchet, Jean-Pierre Rocroi, Bernhard Hausdorf, Andrzej Kaim, Yasunori Kano, Alexander Nützel, Pavel Parkhaev, Michael Schrödl and Ellen E. Strong. 2017. Revised Classification, Nomenclator and Typification ...

), which has a similar shell, acknowledging the

convergence Convergence may refer to: Arts and media Literature *''Convergence'' (book series), edited by Ruth Nanda Anshen * "Convergence" (comics), two separate story lines published by DC Comics: **A four-part crossover storyline that united the four Wei ...

in the different lineages of

s on land.

Description

''Euthema annae'' has a shell which is almost cylindrical with 6 weakly convex whorls, ribbed, with strong constriction. Aperture almost heart-shaped with parietal inclusion. Umbilicus narrow. Periumbilical keel weak. Height of shell tall and wide. ''E. myanmarica'' has a shell which is almost cylindrical, comprising 6 moderately convex whorls, ribbed, with weak constriction. The aperture is oval and the umbilicus wide, with a strong periumbilical keel. The shells are and wide. ''E. truncatellina'' has a shell which is almost cylindrical, comprising 6.5 moderately convex whorls, ribbed, with weak constriction. The aperture is circular, the umbilicus narrow, and the periumbilical keel is absent. The shells are and wide.

References

Links

MolluscaBase - ''Euthema''
{{Diplommatinidae-stub Diplommatinidae Burmese amber Prehistoric gastropod genera