Heteractinida Explained

Heteractinida is an extinct grade of Paleozoic (Cambrian–Permian) sponges, sometimes used as a class or order. They are most commonly considered paraphyletic with respect to Calcarea (calcareous sponges),^{[1] [2] [3]} though some studies instead argue that they are paraphyletic relative to Hexactinellida (glass sponges).^[4] Heteractinids can be distinguished by their six-pronged (snowflake-shaped) spicules, whose symmetry historically suggested a relationship with the triradial calcarean sponges.

The sponge-like Cambrian Hetairacyathidae may be related to heteractinids, though most instead consider hetairacyathids to be closer to archaeocyaths and radiocyaths.^[5] An example of a species in the Heteractinida class is the Gondekia Lancifer; the Gondekia lancifer specimen is only the second articulated specimen known and is more complete than the holotype. It has an intact skeleton of felted sexiradiates of three orders of spicules.^[6]

Subgroups

From Treatise on Invertebrate Paleontology:^[7]

• Order †Octactinellida Hinde, 1887
  • Family †Astraeospongiidae Miller, 1889 [Cambrian–Devonian]
  • Family †Eiffeliidae Rigby, 1986 [Cambrian–Mississippian]
  • Family †Nuchidae Pickett, 2002 [Cambrian]
  • Family †Wewokellidae King, 1943 [Mississippian–Permian]

Notes and References

1. Book: Pickett, J. . Systema Porifera: A Guide to the Classification of Sponges . . 2002 . 978-0-306-47260-2 . Hooper . J.N.A. . Boston, MA . 1121–1140 . †Order Heteractinida Hinde, 1887 . 10.1007/978-1-4615-0747-5_117 . Van Soest . R.W.M. . Willenz . P..
2. Book: Jain, Sreepat . Fundamentals of Invertebrate Palaeontology . 2017 . Springer India . 978-81-322-3656-6 . Springer Geology . New Delhi . 7–30 . Sponges . 10.1007/978-81-322-3658-0.
3. Nadhira . Ardianty . Sutton . Mark D. . Botting . Joseph P. . Muir . Lucy A. . Gueriau . Pierre . King . Andrew . Briggs . Derek E. G. . Siveter . David J. . Siveter . Derek J. . 2019 . Three-dimensionally preserved soft tissues and calcareous hexactins in a Silurian sponge: implications for early sponge evolution . Royal Society Open Science . en . 6 . 7 . 190911 . 10.1098/rsos.190911 . 2054-5703 . 6689616 . 31417767.
4. 10.1073/pnas.0405867102 . Botting . J. P. . Butterfield . N. J. . Valentine . J. W. . 2005 . Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott . Proceedings of the National Academy of Sciences of the United States of America . 102 . 5 . 1554–1559 . 3374469 . 15665105 . 547825 . free .
5. Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volumes 4 & 5: Hypercalcified Porifera, Paleozoic Stromatoporoidea & Archaeocyatha, liii + 1223 p., 665 figs., 2015, available here. .
6. Rigby . J. Keith . 1994 . Well-Preserved Specimens of the Sponges Gondekia (Heteractinida) and Pseudohydnoceras (Hexactinellida), Middle Devonian of New York State . Journal of Paleontology . 68 . 4 . 727–734 . 0022-3360.
7. 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. .