This will be an Evergreen post as I continually add references and make notes.

Austin, W.C., Ott, B.S., Reiswig, H.M., Romagosa, P. and McDaniel, N.G., 2013. Two new species in the family Axinellidae (Porifera, Demospongiae) from British Columbia and adjacent waters. ZooKeys, (338), p.11.

Austin, W.C., Ott, B.S., Reiswig, H.M., Romagosa, P. and McDaniel, N.G., 2014. Taxonomic review of Hadromerida (Porifera, Demospongiae) from British Columbia, Canada, and adjacent waters, with the description of nine new species. Zootaxa, 3823(1), pp.1-84.

Bakus, G.J., 1966. Marine poeciloscleridan sponges of the San Juan Archipelago, Washington. Journal of Zoology, 149(4), pp.415-531.

De Laubenfels, M.W., 1927. XXIV.—The red sponges of Monterey Peninsula, California. Journal of Natural History, 19(110), pp.258-266.

De Laubenfels, M.W., 1929. The sponges of California. PhD dissertation. Stanford University.

De Laubenfels, M.W., 1932. The marine and fresh-water sponges of California. Proceedings of the United States National Museum, 81(2927), pp. 1-140

De Laubenfels, M.W., 1935. Some Sponges of Lower California (Mexico). American Museum Novitates, 779, pp. 1–14.

De Laubenfels, M.W. de (1961) Porifera of Friday Harbour and vicinity. Pacific Science, 15, 192–202.

Dickinson, M.G., 1945. Sponges of the Gulf of California. In: Reports on the collections obtained by Alan Hancock Pacific Expeditions of Velero III off the coast of Mexico, Central America, South America, and Galapagos Islands in 1932, in 1933, in 1934, in 1935, in 1936, in 1937, in 1939, and 1940. The University of Southern California Press, Los Angeles, California, pp. 1–55, pls.1–97.

Dinn, C., Ott, B., Bouchard Marmen, M., Steeves, R., Côté, G., Hayes, V., Nozères, C., Everett, M.V., Powell, A. and Chu, J.W., 2023. Two large structure-forming sponges from opposite North American coasts: a taxonomic review of Arctic–Pacific Mycale (Mycale) loveni and the description of a new Arctic–Atlantic Mycale. Canadian Journal of Zoology, 101(9), pp.807-823.

Duplessis, K. and Reiswig, H.M., 2004. Three new species and a new genus of Farreidae (Porifera: Hexactinellida: Hexactinosida). Proceedings of the Biological Society of Washington, 117(2), pp.199-212.

Harbo, R.M., Ott, B., Reiswig, H.M. and McDaniel, N., 2021. First Canadian record (Ladysmith Harbour, British Columbia) of the non-native European sponge Hymeniacidon perlevis (Montagu, 1814)(Porifera, Demospongiae). BioInvasions Record, 10(2).

Hooper, J.N. and Van Soest, R.W., 2002. Systema Porifera. A guide to the classification of sponges. In Systema Porifera: A guide to the classification of sponges (pp. 1-7). Boston, MA: Springer Us.

Kahn, A.S., Geller, J.B., Reiswig, H.M. and Smith, K.L., 2013. Bathydorus laniger and Docosaccus maculatus (Lyssacinosida; Hexactinellida): Two new species of glass sponge from the abyssal eastern North Pacific Ocean. Zootaxa, 3646, pp.386-400.

Kelly, M., Sim-Smith, C., Stone, R., Samaai, T., Reiswig, H. and Austin, W., 2016. New taxa and arrangements within the family Latrunculiidae (Demospongiae, Poecilosclerida). Zootaxa, 4121(1), pp.1-48.

Klontz, S.W. (1989) Ecology and systematics of the intertidal sponges of Southeast Farallon Island. Master's Dissertation. San Francisco State University, San Francisco, California, 144 pp.

Lambe, L.M. (1892 [1893]) On some Sponges from the Pacific Coast of Canada and Behring Sea. Transactions of the Royal Society of Canada, 10 (4), 67–78, pls. III–VI.

Lambe, L.M. (1893 [1894]) Sponges from the Pacific coast of Canada. Transactions of the Royal Society of Canada, 11 (4), 25–43, pls. II–IV.

Lambe, L.M. (1894 [1895]) Sponges from the Western Coast of North America. Transactions of the Royal Society of Canada, 12 (4), 113–138, pls. II–IV.

Law, L.K., Reiswig, H.M., Ott, B.S., McDaniel, N., Kahn, A.S., Guillas, K.C., Dinn, C. and Leys, S.P., 2020. Description and distribution of Desmacella hyalina sp. nov.(Porifera, Desmacellidae), a new cryptic demosponge in glass sponge reefs from the western coast of Canada. Marine Biodiversity, 50(4), p.55.

Lee, W.L., Elvin, D.W. and Reiswig, H.M., 2007. The sponges of California: A guide and key to the marine sponges of California. Monterey Bay Sanctuary Foundation.

Lee, W.L., Reiswig, H.M., Austin, W.C. and Lundsten, L., 2012. An extraordinary new carnivorous sponge, C hondrocladia lyra, in the new subgenus S ymmetrocladia (D emospongiae, C ladorhizidae), from off of northern C alifornia, USA. Invertebrate Biology, 131(4), pp.259-284.

Lehnert, H., Conway, K.W., Barrie, J.V. and Krautter, M., 2005. Desmacella austini sp. nov. from sponge reefs off the Pacific coast of Canada. Contributions to Zoology, 74(3-4), pp.265-270.

Lehnert, H. and Stone, R.P., 2016. A comprehensive inventory of the Gulf of Alaska sponge fauna with the description of two new species and geographic range extensions. Zootaxa, 4144(3), pp.365-382.

Lundsten, L., Reiswig, H.M. and Austin, W.C., 2014. Four new species of Cladorhizidae (Porifera, Demospongiae, Poecilosclerida) from the Northeast Pacific. Zootaxa, 3786(2), pp.101-123.

Lundsten, L., Reiswig, H.M. and Austin, W.C., 2017. Three new species of Cladorhiza (Demospongiae, Poecilosclerida, Cladorhizidae) from the Northeast Pacific Ocean.

Ott, B. and Reiswig, H.M., 2019. Re-description and Proposed Reclassification of Myxilla (Burtonanchora) lacunosa Lambe, 1893. Zootaxa, 4686(3), pp.zootaxa-4686.

Ott, B., Reiswig, H.M., McDaniel, N. and Harbo, R., 2019. New Species of Lissodendoryx Topsent, 1892 (Demospongiae, Poecilosclerida, Coelosphaeridae) and Myxilla Schmidt, 1862 (Demospongiae, Poecilosclerida, Myxillidae) from the Northeast Pacific. Zootaxa, 4700(1), pp.1-29.

Ott, B., McDaniel, N. and Humphrey, E., 2024. Fourteen new species of demosponges (Porifera) from three coastal fjords in southern British Columbia, Canada. Zootaxa, 5463(2), pp.151-200.

Reiswig, H.M., 2014. Six new species of glass sponges (Porifera: Hexactinellida) from the north-eastern Pacific Ocean. Journal of the Marine Biological Association of the United Kingdom, 94(2), pp.267-284.

Reiswig, H.M., 2015. First Lanuginellinae (Porifera, Hexactinellida, Rossellidae) from the NE Pacific and first species of Doconesthes from the Pacific Ocean. Zootaxa, 3920(4), pp.572-578.

Reiswig, H.M., 2018. Four new species of Hexactinellida (Porifera) and a name replacement from the NE Pacific. Zootaxa, 4466(1), pp.124-151.

Reiswig, H.M., 2020. Report of Cladorhiza bathycrinoides Koltun (Demospongiae) from North America and a new species of Farrea (Hexactinellida) among sponges from Cordell Bank, California. Zootaxa, 4747(3), pp.zootaxa-4747.

Reiswig, H.M., Dohrmann, M., Pomponi, S. and Woerheide, G., 2008. Two new tretodictyids (Hexactinellida: Hexactinosida: Tretodictyidae) from the coasts of North America. Zootaxa, 1721(1), pp.53-64.

Reiswig, Henry M.; Harris, Nathan A. Harris, 2020, "Systematics Compilations on Various Sponge Taxa", https://doi.org/10.5683/SP2/XMA1JW, Borealis, V1

Reiswig, Henry M.; Harris, Nathan A., 2020, "Notes, Illustrations and Annotations on Sponge Specimens", https://doi.org/10.5683/SP2/N5SWPE, Borealis, V1

Reiswig, H.M. and Kaiser, H., 1989. Description of Mycale bamfieldense n. sp.(Porifera, Demospongiae, Poecilosclerida) from Vancouver Island, British Columbia. Canadian journal of zoology, 67(3), pp.674-677.

Reiswig, H.M. and Lee, W.L., 2007. A new species of Cladorhiza (Porifera: Cladorhizidae) from S. California (USA). Porifera research: biodiversity, innovation, sustainability. Série Livros, 28, pp.517-523.

Reiswig, H.M. and Stone, R.P., 2013. New glass sponges (Porifera: Hexactinellida) from deep waters of the central Aleutian Islands, Alaska. Zootaxa, 3628(1), pp.1-64.

Samaai, T., Gibbons, M.J. and Kelly, M., 2006. Revision of the genus Latrunculia du Bocage, 1869 (Porifera: Demospongiae: Latrunculiidae) with descriptions of new species from New Caledonia and the Northeastern Pacific.

Stone, R.P., Lehnert, H. and Reiswig, H.M., 2011. A guide to the deep-water sponges of the Aleutian Island Archipelago (Vol. 12). US Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Scientific Publications Office.

Turner, T.L., 2020. The order Tethyida (Porifera) in California: taxonomy, systematics, and the first member of the family Hemiasterellidae in the Eastern Pacific. Zootaxa, 4861(2).

Turner, T.L., 2021. Four new Scopalina from Southern California: the first Scopalinida (Porifera: Demospongiae) from the temperate Eastern Pacific. Zootaxa, 4970(2).

Turner, T.L. and Lonhart, S.I., 2023. The Sponges of the Carmel Pinnacles Marine Protected Area. Zootaxa, 5318(2), pp.151-194.

Turner, T.L., Rouse, G.W., Weigel, B.L., Janusson, C., Lemay, M.A. and Thacker, R.W., 2024. Taxonomy and phylogeny of the family Suberitidae (Porifera: Demospongiae) in California. bioRxiv, pp.2024-01.

Background:

The #1 assumption used by sponge biologists when identifying a sponge is that you can't reliably identify it with just a photo and without context. The scientific gold-standard for identifying a sponge is notoriously difficult to perform and involves taxonomic protocols that needs caustic chemicals, microscopy, and fluency in taxonomy jargon. Tell me the last time you heard somebody use "oxyhexaster microsclere" in a sentence that didn't involve sponge taxonomy?

As a biodiversity scientist and a sponge ecologist in a past life, I've continually thought about bridging old-school methods with new-school technology (e.g. iNaturalist). In other words, can we find some general rules that everybody can use to narrow down the identification process for what is paradoxically the most common marine animal in Earth's history but also the most ignored by most marine biologists?

I've dug through much of the iNat sponge observations in the Pacific Northwest over the past few years to get a sense of what are the most photographed sponge morphotypes (i.e., whole-sponge shape/color/form that may or may not represent a single species) where the science jury is still out on the taxonomy to allow these observations to be useful 'biodiversity data'. I feel a little bit of scientific detective work could go a long way with resolving the confidence in the ID of these common encounters in the rocky intertidal.

Ground rules (basic assumptions when identifying sponges):

(I) Sponges are the poster child of what it means to be 'phenotypically plastic'.

Many species are expected to have a diverse range of whole sponge morphotypes. As in, the same species could be a flat featureless, encrusting blob in some areas, but also be an erect, branching form in others. Very often, this is in response to the environment such as gradients of wave action between sites (low to high).[1]

(II) Diagnostic analyses of the presence, absence, and morphometrics of microscopic skeletal features (i.e., spicules) are still the gold-standard for identifying a sponge to species with the highest level of confidence.[2]

(III) Official species names for sponges are frequently being revised. In other words, their scientific names are constantly changing.

Some commonly photographed sponge morphotypes in the Pacific Northwest.

(I) The purple-encrusting, intertidal demosponge

Phylum: Porifera (high certainty)
Class: Demospongiae (high certainty)
Order: Haplosclerida (likely)

What the iNaturalist AI algorithm has commonly identified this as: Haliclona cinerea
What popular field guides have synonymized this as: Haliclona permollis, Haliclona cinerea, Reniera cinera, Reniera rufescens, Haliclona sp., Undetermined sponge.[3][4][5]

Sponge thoughts: Neither of the two most commonly applied species-level IDs used to identify this sponge on iNaturalist, Haliclona cinerea and H. permollis, are actually scientifically valid names for sponges. H. permollis is no longer recognized. H. cinerea is split with a subspecies to H. (Reniera) cinerea which appears to originate as a species described from waters around Britian.[6] It's rare to have scientific evidence that validates a marine species with having a "globally cosmopolitan distribution". The more common scenario I've encountered is that this had been an unvalidated assumption and upon further inspection, the extrapolated species is a 'new species'.

Regardless, the bigger issue is this morphotype is more than likely not a single species but a complex that includes several genus and species. The last I checked, we likely have undescribed species hiding within this complex on this coast - see this observations' comments for scientific dialogue/context (). It would be interesting to combine proper sponge taxonomy with an understanding of the established marine biogeographic/oceanography history of the Pacific Northwest for this morphotype. The true identities of this super common, yet understudied sponge morphotype. My hand-wavey prediction is that there is at least n=8 cryptic species with this morphotype occurring in the Pacific Northwest. I'm also speculating that 'purple' is not a fixed trait and that what can be purple can also be yellow, green, and beige..

(II) The red-encrusting, intertidal demosponge.

Phylum: Porifera (high certainty)
Class: Demospongiae (high certainty)
Order: Poecilosclerida (likely)
Family: Microcionidae (likely)
What the iNaturalist AI algorithm has commonly identified this as: Clathria pennata
What popular field guides have synonymized this as: Ophlitaspongia pennata, Desmacella pennata, Biemna pennata, Tylodesma pennata, Clathria pennata, Clathria sp., Undetermined sponge.[3][4]

Sponge thoughts: The genus Clathria is also complex with a diverse number of associated species.[7] I would like to guess that there are a number of cryptic species sharing this morphotype in the Pacific Northwest but this one seems to have gotten less attention over the years compared to the encrusting purple morphotype. The latter's plasticity and taxonomic chaos is much more well known.

Marine invertebrate zoology courses with field trips in the Pacific Northwest (e.g. British Columbia, Washington, Oregon) often go looking for animals at low tide. Instructors would often find this common bright red sponge as an example of the phylum Porifera and call it "Ophlitaspongia" while also mentioning the natural history note of the associated red dorid nudibranch Rostanga pulcra which is often camouflaged and feeding on this sponge. While the natural history fact is still accurate (see the photo for the red nudibranchs!), the genus Ophlitaspongia is not scientifically valid anymore. I'd be curious to know if R. pulcra feeds on all species with this morphotype or if it was selective?

Trailing thoughts

There are a few more sponge morphotypes that jump to mind (e.g. 'boot' sponges, Class hexactinellida) but I'll leave this post at two for now. One of my past research projects involved developing models that could predict areas of sponge habitat throughout the Pacific Northwest [8]. A task that required sourcing reliable sources of georeferenced, sponge observations (e.g. museum records). I briefly considered iNaturalist at the start but stopped with 'needs further work on the species IDs' when I encountered how inaccurate some of the common sponges were being done. Since then, there has been some improvements made by others - have a look at some of the efforts @tomleeturner to implement sponge identifying protocols using spicule analysis (and even DNA analysis) with iNaturalist photographs for each georeferenced individual observation as a template to emulate [9].

References:

[1] Palumbi, S.R., 1986. How body plans limit acclimation: responses of a demosponge to wave force. Ecology, 67(1), pp.208-214.

[2] Hooper, J.N. and Van Soest, R.W., 2002. Systema Porifera. A guide to the classification of sponges. In Systema Porifera: A guide to the classification of sponges (pp. 1-7). Boston, MA: Springer Us.

[3] Lamb, A. and Hanby, B.P., 2005. Marine life of the Pacific Northwest: a photographic encyclopedia of invertebrates, seaweeds and selected fishes. Harbour Publishing.

[4] Harbo, R.M., 2022. Whelks to whales: coastal marine life of the Pacific Northwest. Harbour Publishing.

[5] Invertebrates of the Salish Sea

[6] WoRMS taxon details - Haliclona (Reniera) cinerea (Grant, 1826)

[7] WoRMS taxon details - Clathria (Schmidt, 1862)

[8] Modelling the environmental niche space and distributions of cold-water corals and sponges in the Canadian northeast Pacific Ocean

[9] https://www.inaturalist.org/observations?place_id=any&project_id=marine-sponges-of-the-pacific-northwest&user_id=tomleeturner&verifiable=any