Lychniscosida Explained

Lychniscosida (sometimes spelled Lychniscosa) is an order of sponges belonging to the class Hexactinellida and subclass Hexasterophora.^[1] They are dictyonal sponges (with parenchymal spicules fully fused into a 3D framework) characterized by the presence of additional struts at the nodes of the skeleton. These struts create octahedral frames, known as lychniscs ("lanterns").

Most members of the order are extinct, with their highest diversity as major reef builders in the Jurassic and Cretaceous periods.^[2] A few uncertain^[3] claims of Triassic lychniscosids have also been reported from China.^{[4] [5]} Only three genera are still alive today:^[6] Lychnocystis (family Aulocystidae), Neoaulocystis (family Aulocystidae), and Scleroplegma (family Diapleuridae).

Families

• Aulocystidae [Cretaceous–Holocene]
• †Callodictyonidae [Upper Jurassic<ref name=":02" />–Oligocene]
• †Calyptrellidae [Upper Cretaceous]
• †Camerospongiidae [Cretaceous]
• †Coeloptychidae [Cretaceous]
• †Cypelliidae [Jurassic]
• †Dactylocalycidae [Jurassic–Upper Cretaceous]
• Diapleuridae [Eocene<ref name=":1">{{Cite journal |last1=Frisone |first1=Viviana |last2=Pisera |first2=Andrzej |last3=Preto |first3=Nereo |date=2016-01-18 |title=A highly diverse siliceous sponge fauna (Porifera: Hexactinellida, Demospongiae) from the Eocene of north-eastern Italy: systematics and palaeoecology |url=http://dx.doi.org/10.1080/14772019.2015.1132015 |journal=Journal of Systematic Palaeontology |volume=14 |issue=11 |pages=949–1002 |doi=10.1080/14772019.2015.1132015 |issn=1477-2019 |s2cid=87329356}}</ref>–Holocene]
• †Polyblastidiidae [Upper Jurassic–Cretaceous]
• †Sporadopylidae [Upper Jurassic–Cretaceous]
• †Ventriculitidae [Jurassic–Upper Cretaceous]

Notes and References

1. Web site: Lychniscosida . www.gbif.org . 14 May 2021 . en.
2. Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volume 3: Classes Demospongea, Hexactinellida, Heteractinida & Calcarea, xxxi + 872 p., 506 fig., 1 table, 2004, available here. .
3. Pisera . Andrzej . Bodzioch . Adam . 1991 . Middle Triassic lyssacinosan sponges from Upper Silesia (southern Poland), and the history of hexactinosan and Iychniscosan sponges . Acta Geologica Polonica . 41 . 3–4 . 193–207.
4. Wendt . J. . Wu . Xichun . Reinhardt . J.W. . 1989 . Deep-water hexactinellid sponge mounds from the upper triassic of northern Sichuan (China) . Palaeogeography, Palaeoclimatology, Palaeoecology . en . 76 . 1-2 . 17–29 . 10.1016/0031-0182(89)90100-4.
5. Wendt . Jobst . 2001 . Upper Triassic (Carnian) mud mounds from northern Sichuan (China) . Acta Geologica Polonica . 51 . 1 . 1–13.
6. Lychniscosida.