Belongs within: Miliolina.
Triloculina is a genus of miliolid Foraminifera known from the Jurassic to the present, in which only the final three chambers are visible externally at maturity. The aperture is simple and rounded with a bifid tooth (Loeblich & Tappan 1964).
Characters (Loeblich & Tappan 1964): Test free, with chambers each one-half coil in length, early chambers at least in microspheric generation in quinqueloculine arrangement, later triloculine, with successive chambers added in planes 120° apart, only final three chambers visible externally; wall calcareous, imperforate, porcellaneous, or rarely with surficial agglutinated layer; aperture terminal, typically with bifid tooth; gametes biflagellate, with axostyle.
Triloculina d’Orbigny 1826S-VC91 (see below for synonymy)
|--*T. trigonula (Lamarck 1804)LT64 [=Miliolites trigonulaLT64, Miliola trigonulaC40]
|--T. affinis d’Orbigny 1826A68
|--‘Miliolina’ australisLJ98
|--T. bertheliniana (Brady 1884)A68
|--T. bicarinataC40
|--T. brevidentataLT64
|--T. circularisLT64
|--T. cuneataM62
|--T. dilatataM62
|--‘*Renoidea’ glabra Brown 1827LT64
|--‘*Spidestomella’ globulifera Costa 1856LT64
|--T. labiosaM62
|--T. laevigata d’Orbigny 1826 [=*Miliolina laevigata]LT64
|--T. marioniM62
|--T. oblonga (Montagu 1803)A68
|--T. parisaS05
|--T. quadrataS05
|--‘Miliolina’ reussiLT64
|--T. rotundaLT64
|--T. schreibersianaM62
|--T. squamosaLT64
|--T. striatotrigonula Parker & Jones 1865A68
|--T. strigillata d’Orbigny 1850 [=*Trillina strigillata]LT64
|--T. suborbicularisLT64
|--T. tricarinata d’Orbigny 1826H03
|--T. triquetrellaS05
|--T. turkomanica Brodsky 1929G86
|--T. webbianaM62
`--T. wiesneriM62
Triloculina d’Orbigny 1826S-VC91 [incl. Miliolina Williamson 1858LT64, Renoidea Brown 1927LT64, Spidestomella Costa 1856LT64, Trillina Munier-Chalmas 1882LT64; Triloculininae]
*Type species of generic name indicated
References
[A68] Albani, A. D. 1968. Recent Foraminiferida of the central coast of New South Wales. AMSA Handbook 1: 1–37.
[C40] Cushman, J. A. 1940. Foraminifera: Their classification and economic use 3rd ed. Harvard University Press: Cambridge (Massachusetts).
[G86] Golemansky, V. G. 1986. Rhizopoda: Foraminiferida. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 17–20. E. J. Brill/Dr. W. Backhuys: Leiden.
[H03] Hanagata, S. 2003. Miocene-Pliocene Foraminifera from the Niigata oil-fields region, northeastern Japan. Micropaleontology 49 (4): 293–340.
[LJ98] Li, Q., N. P. James, B. McGowran, Y. Bone & J. Cann. 1998. Synergetic influence of water masses and Kangaroo Island barrier on foraminiferal distribution, Lincoln and Lacepede shelves, South Australia: a synthesis. Alcheringa 22 (2): 153–176.
[LT64] Loeblich, A. R., Jr & H. Tappan. 1964. Sarcodina: chiefly “thecamoebians” and Foraminiferida. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt C. Protista 2 vol. 1. The Geological Society of America and The University of Kansas Press.
[M62] Monniot, F. 1962. Recherches sur les graviers a Amphioxus de la région de Banyuls-sur-Mer. Vie et Milieu 13: 231–322.
[S-VC91] Segura-Vernis, L. R., & A. L. Carreño. 1991. Foraminíferos y ostrácodos de la Laguna de La Paz, Baja California Sur, México. Inv. Mar. CICIMAR 6 (1): 195–224.
[S05] Semeniuk, T. A. 2005. Fossil foraminiferal assemblages from Pleistocene seagrass-bank deposits of the southern Perth Basin, Western Australia, and their palaeotemperature implications. Journal of the Royal Society of Western Australia 88 (4): 177–190.