Harp Sponge

Webpage by Peter Miller

Kingdom: Animalia

Phylum: Porifera

Class: Demospongiae

Order: Poeciliosclerida

Family: Cladorhizidae

Genus: Chondrocladia

Species: Chondrocladia lyra

Discovery and Habitat

Chondrocladia lyra was initially described from two collected specimens found in the Northeast Pacific Ocean along Escanaba Ridge and Monterey Canyon California, USA. Alongside the two collected specimens, a team led by senior research technician Lonny Lundsten operated deep-diving vessels to obtain video and photo information for 10 more specimens. Chondrocladia lyra has been found in deep-sea sites at depths between 3316 and 3399 meters.

Morphology

The basic structure, which is known as a vane, is harp or lyre-shaped. Between 1 and 6 vanes extend from the center of the harp sponge, forming several types of radial symmetry depending on the number of vanes. Each vane contains a horizontal stolon that supports upright branches which terminate with a swollen ball. Along with the terminal swollen ball, swellings occur midway along the branches. The terminal swollen balls are the sites of spermatophore production and release while the midway swellings are sites for oocyte maturation. All surfaces of the harp sponge are covered in anchorate isochelae.

Feeding

The harp sponge is able to catch prey, envelope it in a membrane and digest it whole. Based on footage of several individuals and two large, fragmentary specimens brought up by the ROVs, Lundsten’s team described how the vertical branches that make up the sponge’s basic harp-like structure are covered in barbed hooks and spines. They found that a number of crustacean prey were passively ensnared on these branches thanks to the Velcro-like hooks and then aggressively enclosed in a cavity to be dismembered into small, digestible particles, which provided direct evidence of the species’ carnivorous appetites.

Carnivorous Sponge?

Perhaps surprisingly, Chondrocladia lyra is not the only known carnivorous sponge, with nearly 200 species described. Through extensive evolutionary analysis, carnivorous sponges as a whole have been found to be a monophyletic group, including the harp sponge. Carnivorous sponges are characterized by their unique method of capturing mesoplanktonic prey coupled with the complete or partial reduction of the aquiferous system. Although there are several spicule differences amongst carnivorous sponges, current knowledge suggests that sponge carnivory has only evolved once.

Life Cycle

The harp sponge has a very interesting life cycle, which includes the release of spermatophores from the swollen balls at the end of each branch. These sperm packets float until they are received from another harp sponge individual on one of its branches or spicules. Shortly after the reception of the spermatophore, the formation of another organism is initiated. The formation of fertilization is apparent through swelling found along the branches. It is thought that the sponge’s “harp-like” shape has evolved in order to increase the exposure that an individual has to receive spermatophores as well as capture food.

Literature Cited

Crew, Becky. “New Carnivorous Harp Sponge Discovered in Deep Sea.” Nature News, Nature Publishing Group, 9 Nov. 2012, https://www.nature.com/articles/nature.2012.11789.

Gross, Michael. “Magical Mysteries of Marine Sponges.” Current Biology, Cell Press, 25 Jan. 2021, https://www.sciencedirect.com/science/article/pii/S0960982220318832?casa_token=4TWt7YdCPpMAAAAA%3AxYg_5-Vc1-1dzvmXUJdmtiR5YuryaSyxNxW2u02K7m3WxWEE6Gsc9L5EOaY2x1rnrtEIgBFMtkDe.

Hestetun, Jon Thomassen, et al. “Deep-Sea Carnivorous Sponges from the Mariana Islands.” Frontiers, Frontiers, 1 Jan. 1AD, https://internal-journal.frontiersin.org/articles/10.3389/fmars.2019.00371/full.

Hestetun, Jon Thomassen, et al. “The Systematics of Carnivorous Sponges.” Molecular Phylogenetics and Evolution, Academic Press, 28 Sept. 2015, https://www.sciencedirect.com/science/article/pii/S1055790315002535

Lee, Welton L., et al. “An Extraordinary New Carnivorous Sponge, Chondrocladia Lyra, in the New Subgenus Symmetrocladia (Demospongiae, Cladorhizidae), from off of Northern California, USA.” Wiley Online Library, John Wiley & Sons, Ltd, 18 Oct. 2012, https://onlinelibrary.wiley.com/doi/full/10.1111/ivb.12001?casa_token=S_OlRLPj36cAAAAA%3A44uQDkPP9oz6QMatMie6o9Sdx4TNnenUPfTh9lnnuHXljAj-HJ31gPx_eoIVnHG3_K5EIWAzoLdT4RQ59w.

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