
Belongs within: Clypeasteroida.
The Laganidae are a group of sand dollars known from the Oligocene to the present of the tropical Indo-Pacific, as well as the Eocene of Europe (Durham 1966).
Characters (from Durham 1966): Test flattened, outline angulated to rounded; petals well developed, open, outer member of pore pair slightly elongated, pores usually conjugate; ambulacral food grooves present, simple, not reaching margin; interambulacra very narrow on oral surface, terminal apical plate rhomboidal; basicoronal plates forming pentameral star with ambulacral plates at apices of rays; no abrupt change in size of oral ambulacral plates; ambulacral plates not pseudocompound in petals; internal supports both radial and concentric; periproct oral.
<==LaganidaeD66 |--Fibulina Tornquist 1904D66 | `--*F. gracilis Tornquist 1904 [incl. Fibularia voeltzkowi Tornquist 1904]M89 |--Hupea Pomel 1883D66 | `--*H. decagonale (Lesson 1883)M89 [=Laganum decagonalisM89, Scutella decagonalisD66] |--Peronellites Hayasaka & Morishita 1947D66 | `--*P. ovalis Hayasaka & Morishita 1947M89 [=Peronella (*Peronellites) ovalisD66] |--Rumphia Desor 1858 (see below for synonymy)D66 | `--*R. rostrata (Agassiz 1841) [=Laganum rostratum]M89 |--Sismondia Desor 1858D66 | |--*S. occitana (Defrance 1827) [=Scutella occitana]M89 | `--S. barabirensis Lambert 1931SG93 |--Jacksonaster Lambert & Thiéry 1914D66 | |--*J. conchatus (M’Clelland 1840) [=Echinarachnius conchatus]M89 | `--J. depressum [=Laganum depressum]D66 |--Peronella Gray 1855BM09, M89 | |--*P. peronii (Agassiz 1841) [=Laganum peronii]M89 | |--P. japonicaD66 | |--P. lesueuri (Valenciennes 1841)SM15 | |--P. macroproctes Koehler 1922SM15 | |--P. orbicularis (Leske 1778)BM09 | |--P. pellucidaM89 | `--P. tuberculata Mortensen 1918SM15 `--Laganum Link 1807M89 (see below for synonymy) |--*L. laganum (Leske 1778)M89 (see below for synonymy) |--L. dickersoniD66 | |--L. d. dickersoniD66 | `--L. d. keienseD66 |--L. fudsiyamaD66 `--L. sorigneti Cotteau 1890SG93
Laganum Link 1807M89 [incl. Echinodiscus Lambert & Thiéry 1914 nec Leske 1778 nec Worthen & Miller 1883 nec Stürtz 1899D66, Lagana Gray 1825D66]
*Laganum laganum (Leske 1778)M89 [=Echinodiscus laganumM89; incl. *Lagana minor Gray 1825D66, Laganum petalodes Link 1807D66]
Rumphia Desor 1858 [incl. Michelinia Dujardin & Hupé 1862 non de Koninck 1842, Polyaster Michelin 1859 non Gray 1840]D66
*Type species of generic name indicated
References
[BM09] Bryce, C., & L. Marsh. 2009. Echinodermata (Asteroidea, Echinoidea and Holothuroidea) of Mermaid (Rowley Shoals), Scott and Seringapatam Reefs, Western Australia. Records of the Western Australian Museum Supplement 77: 209–220.
[D66] Durham, J. D. 1966. Clypeasteroids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 2 pp. U450–U491. The Geological Society of America, Inc., and The University of Kansas Press.
[M89] Mooi, R. 1989. Living and fossil genera of the Clypeasteroida (Echinoidea: Echinodermata): an illustrated key and annotated checklist. Smithsonian Contributions to Zoology 488: 1–51.
[SM15] Sampey, A., & L. M. Marsh. 2015. Kimberley marine biota. Historical data: echinoderms. Records of the Western Australian Museum Supplement 84: 207–246.
[SG93] Simms, M. J., A. S. Gale, P. Gilliland, E. P. F. Rose & G. D. Sevastopulo. 1993. Echinodermata. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 491–528. Chapman & Hall: London.