Hallirhoidae

{{Short description|Extinct family of sponges}}

{{Automatic taxobox

| fossil_range = Cretaceous - Eocene

| image = Hallirhoidae.jpg

| image_caption = Various Cretaceous Hallirhoiids

| taxon = Hallirhoidae

| subdivision_ranks = Genera

| subdivision =

• Hallirhoa
• Siphonia
• Callopegma

}}

Hallirhoidae is an extinct family of heteroscleromorph demosponges found throughout the world from the Cretaceous to the Eocene, whereupon they became extinct.{{Cite book|url=https://books.google.com/books?id=cQtQDwAAQBAJ&q=Hallirhoidae&pg=PA266|title=A Concise Dictionary of Paleontology|last=Carlton|first=Robert L.|date=2018-03-07|publisher=Springer|isbn=9783319730554|language=en}} The highest concentration of species occurred in the Tethys Ocean during the upper Cretaceous. The hallirhoid demosponges were very distinctive-looking, largely pear-shaped sponges that were attached to the seafloor by a long stem-like stalk.{{Cite web|url=https://natuurtijdschriften.nl/search?identifier=404798|title=Callopegma en Phymatella, twee tetracladine krijtsponzen van Westerhaar en Sibculo|website=natuurtijdschriften.nl|access-date=2019-01-22}}{{Cite web|url=http://www.thefossilforum.com/index.php?/collections-database/sponges/sponge-r829/|title=Sponge|website=The Fossil Forum|date=16 February 2017 |language=en-US|access-date=2019-05-21}}