Reticulosa

Reticulosa is an extinct order of sea sponges in the class Hexactinellida (glass sponges) and the subclass Amphidiscophora.''Treatise on Invertebrate Paleontology'' Part E, Revised. Porifera, Volume 3: Classes Demospongea, Hexactinellida, Heteractinida & Calcarea, xxxi + 872 p., 506 fig., 1 table, 2004, availabl
here
. Reticulosans were diverse in shape and size, similar to their modern relatives, the amphidiscosidans. Some were smooth and attached to a surface at a flat point, others were polyhedral or ornamented with nodes, many were covered in bristles, and a few were even suspended above the seabed by a rope-like anchor of braided glass spicules.

Reticulosans comprise the vast majority of Paleozoic hexactinellid diversity, though only a few species survived up to the Mesozoic.''Treatise on Invertebrate Paleontology'' Part E, Revised. Porifera, Volume 2: Introduction to the Porifera, xxvii + 349 p., 135 fig., 10 tables, 2003, availabl
here
. They may include the oldest sponge body fossil in the world: '' Palaeophragmodictya'', from the late Ediacaran (~555 Ma), was originally described as a reticulosan based on its mesh-like surface texture. Ediacaran-type preservation has obscured any information about spicule structure, and some authors doubt that ''Palaeophragmodictya'' is a sponge in the first place. Regardless, unambiguous reticulosans appear in the fossil record not much later, in the early Cambrian.

Like most other glass sponges, reticulosans had a skeleton of unfused macroscleres reinforced with microscopic microscleres. Their macroscleres are often stauractines (four-rayed spicules, + shaped), though pentactine (five-rayed) or hexactine (six-rayed) spicules may be predominant in certain regions of the skeleton. The outer layer of the skeleton forms a regular mesh-like pattern, with incrementally smaller spicules filling in the gaps between larger spicules in a fractal pattern. The microscleres, when present, are simple bundled rods (paraclavules).

The living glass sponge '' Sclerothamnus'' is sometimes compared to the reticulosan family Titusvillidae, though it is more commonly placed in the family Tretodictyidae of the order Sceptrulophora.

Subgroups

From the ''Treatise on Invertebrate Paleontology'' (2004), unless otherwise noted:
* Superfamily † Dictyospongioidea Hall & Clarke, 1899
** Family † Dictyospongiidae Hall & Clarke, 1899 diacaran?–Middle Permian (Roadian)** Family † Docodermatidae Finks, 1960 ilurian (Ludlow)–Permian** Family † Stereodictyidae Finks, 1960 arboniferous (Visean)–Upper Triassic (Carnian)* Superfamily † Dierespongioidea Rigby & Gutschick, 1976
** Family † Aglithodictyidae Hall & Clarke, 1899 pper Devonian–Carboniferous (Visean)** Family † Amphispongiidae Rauff, 1894 pper Silurian** Family † Dierespongiidae Rigby & Gutschick, 1976 iddle Ordovician–Lower Permian (Artinskian)** Family † Hydnodictyidae Rigby, 1971 iddle Cambrian–Upper Ordovician** Family † Multivasculatidae Laubenfels, 1955 pper Cambrian** Family † Titusvillidae Caster, 1939 pper Devonian–Lower Mississippian, Holocene?* Superfamily † Hintzespongioidea Finks, 1983
** Family † Hintzespongiidae Finks, 1983 ower Cambrian–Middle Devonian (Givetian)** Family † Teganiidae Laubenfels, 1955 pper Cambrian (Furongian)–Upper Mississippian* Superfamily † Protospongioidea Hinde, 1887
** Family † Asthenospongiidae? Botting, 2004 rdovician** Family † Protospongiidae Hinde, 1887 ower Cambrian–Jurassic** Family † Triactinellidae? _{Botting, 2005} rdovician

References

{{Taxonbar, from=Q7316739

Hexactinellida
Sponge orders
Prehistoric sponges
Prehistoric animal orders