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Test consisting of chambers that are alternately added with respect to the test axis of growth resulting in biserial arrangement in the primitive species and with adult stage with multichamber growth in the evolved one. The adult stage begins with the biaperturate progressive chamber, which is followed by two to three sets of two chambers. Chambers are globular to subglobular, overlapping at various rates. Sutures are distinct and depressed between all the chambers of the test. Periphery is rounded and simple, without peripheral structures. Aperture is a medium high arch at the base of the last formed chamber, simple in the completely biserial tests and multiple in those with the adult flaring stage. Chambers ornamented with longitudinal leptocostae. Test wall calcitic, hyaline and perforate.
Etymology: named after the State of Texas (USA) where the type species was first reported.
Extra details from original publication
Remarks.– Texasina accommodates a directional lineage in the Coniacian-early Campanian, which develops a multichamber growth adult stage. It differs from Sigalia and Proliferania mainly by (i) lacking sutures lined with calyptoridges and phaneroridges, (ii) having a simple periphery, without transverse keels and (iii) fewer chambers in the adult stage with multichamber growth when compared to the end members of either of the two directional lineages. Texasina evolved from the “H.” globulosa group of species, as suggested by the (i) globular to subglobular chambers, (ii) periapertural structures consisting of narrow metaflanges and (iii) leptocostate ornamentation.
Species included.– Texasina papula (Belford, 1960) and T. austinana (Cushman, 1938).
Stratigraphic range.– Coniacian-early Campanian (from the D. concavata Biozone to the G. elevata Biozone).
Geographic distribution.– USA (Texas, Wyoming, Kansas, Nebraska, South Dakota, New Jersey), Canada (British Co- lumbia), Europe (Germany), Central Asia (Azerbaijan), Australia, South Atlantic Ocean (Falkland Plateau) and East Indian Ocean (Exmouth Plateau).
Texasina compiled by the pforams@mikrotax project team viewed: 13-6-2021
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