''Sigmoilinopsis'' is a genus of
miliolid
The Miliolida are an order of foraminifera with calcareous, porcelacous tests that are imperforate and commonly have a pseudochitinous lining. Tests are composed of randomly oriented calcite needles that have a high proportion of magnesium alon ...
Foraminifera, with an ovate test, chambers one-half coil in length, arranged in rapidly changing planes in the early stage resulting in two spiralling series that appear sigmoid in section, gradually becoming planispiral in the adult. Walls are thick, porcelaneous but enclosing a large quantity of agglutinated quartz particles, sponge spicules, and shell fragments; the aperture terminal, rounded, with a small tooth.
''Sigmoilinopsis'' is grossly similar to ''
Sigmoilina'' but with less enveloping chambers allowing earlier ones to be externally visible, and in incorporating agglutinated material.
''Sigmoilinopsis'' is included in the
Hauerinidae
Hauerinidae is a large and diverse family of miliolid forams ( Loeblich & Tappan, 1988) that includes genera distributed among various subfamilies in the Treatise (Loelich &Tappan 1964) as well as genera named and described since.
Diagnosis
T ...
(
Loeblich &
Tappan 1988). Previously it was assigned to the
Miliolidae
''Miliolidae'' is a family in the superfamily ''Miliolacea'' of miliolid foraminifera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists charact ...
(Loeblich & Tappan 1964) and included in the subfamily Quinqueloculininae.
References
* Alfred R. Loeblich Jr and Helen Tappan,1988. Forminiferal Genera and their Classification. e-boo
* Alfred R. Loeblich Jr and Helen Tappan, 1964. Sarcodina Chiefly "Thecamoebians" and Foraminiferida; Treatise on Invertebrate Paleontology, Part C Protista 2. Geological Society of America and University of Kansas Press.
Tubothalamea
Foraminifera genera
Extant Miocene first appearances
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