New marine sponges provide clues about animal evolution

Paco Cárdenas and Julio A. Díaz have described new sponges found off the coast of Spain. The researchers discovered that the sponges produce a substance of potential interest for drug development.
 Photo Credit: Mikael Wallerstedt

A completely new order of marine sponges has been found by researchers at the Museum of Evolution, Uppsala University. The sponge order, named Vilesida, produces substances that could be used in drug development. The same substances support the hypothesis that sponges – and therefore animals – emerged 100 million years earlier than previously thought. 

Sponges are among the most challenging animals in the tree of life to identify and classify. For this reason, many sponges lack a formal name, which is unusual in other animal groups. While the discovery by scientists of new species of marine invertebrates is an everyday occurrence, it is far less common to identify entirely new genera or families. The discovery of a completely new order is rare: only twelve new animal orders have been described in the last five years. 

Adult sponges are attached to the seafloor. Shown here is one of the newly described sponges belonging to the order Vilesida. This particular specimen belongs to the genus Murus.
Photo Credit: Mikael Wallerstedt

In a new study led by the Museum of Evolution at Uppsala University and published in the Zoological Journal of the Linnean Society, researchers have found a completely new order of marine sponges: Vilesida. 

“The discovery of this new order of sponges represents a significant advance in our understanding of sponge classification, evolution and marine biodiversity – and of the early history of life on Earth. Although the external shape of the Vilesida is barely distinguishable from closely related orders, molecular analyses show that they separated way back in the Mesozoic geological era – more than 150 million years ago,” says Julio Díaz, the study’s lead author, and postdoc at the Museum of Evolution, Zoology. 

Adult sponges are attached to the seafloor. Shown here is one of the newly described sponges belonging to the order of Vilesida. This specimen belongs to the genus Murus. Photo: Mikael Wallerstedt 

Sponges collected from the Atlantic and Mediterranean 

Vilesida species are spread across much of the world – from the Caribbean to the Pacific, in the Mediterranean and the Atlantic. Some of the species within Vilesida play important ecological roles, occurring in habitats ranging from tropical coral reefs to deep-sea environments. The study also describes a new family (Vilesidae), a new genus (Murus) and two new species from the north-east Atlantic. 

Several deep-sea specimens from Spain (Atlantic and Mediterranean), collected by means of trawls, dredges or remotely operated vehicles (ROVs), played a key role in the discovery of the new order. Genetic and chemical methods were then used to identify and distinguish the group from other known groups of sponges. 

Julio A. Díaz collected the sponges off the coast of Spain during his PhD work.
Photo Credit: Spanish Institute of Oceanography (IEO), CIRCA-LEBA-0523 cruise, ROV Liropus.

Sponges may have been around 100 million years earlier than previously thought 

The researchers also discovered that Vilesida species produce a very unusual type of sterols as major components of their cells. Sterols are an important part of cell membranes, where they affect membrane fluidity. Instead of using cholesterol, like humans and many other animals, their sterol profile is dominated by 24-isopropylcholesterols (24-ipc sterols) – sterols that have so far only been found in large quantities in these sponges. 

“This discovery is particularly important because these unique sterols exactly match the fossilized steroids believed to be the oldest known animal biomarkers, found in large quantities in Ediacaran rocks older than 600 million years. Our findings thus provide further support for the sponge biomarker hypothesis, which proposes that sponges – and therefore animals – emerged around 100 million years earlier than previously thought,” says Paco Cárdenas, Curator at the Museum of Evolution, Zoology, who led the study 

This hypothesis is also supported by a recent article published in PNAS, in which three of the authors of the current study show that unusual sterols in ancient rocks are very likely to come from early sponges. 

Sponges are the only animals in the world that have a skeleton made of glass.
Photo Credit: Mikael Wallerstedt

Could be used in medicines 

The discovery of Vilesida is interesting not only because it moves back the time at which sponges emerged, but also because they produce these unique sterols. 

“Previous studies by other research teams show that sterols are of great interest as a basis for the development of new antimicrobial, anticarcinogenic and antiviral drugs. Now that the sponges have been named and we know where they are, our discovery can help chemists and pharmacists find these valuable substances more easily,” says Paco Cárdenas. 

Published in journal: Zoological Journal of the Linnean Society

Title: Vilesida, a new order of demosponges revealed by molecular phylogeny and abundant 24-isopropylcholesterols (24-ipc sterols)

Authors: Julio A Díaz, Ana De la Torriente, J Alex Zumberge, Pilar Ríos, Alberto Serrano, Javier Cristobo, Sergi Taboada, Carlota Gracia-Sancha, Ana Riesgo, Gordon D Love, Enric Massutí, and Paco Cárdenas

Previous study: Chemical characterization of C31 sterols from sponges and Neoproterozoic fossil sterane counterparts (PNAS)

Source/Credit: Uppsala University | Sandra Gunnarsson

Reference Number: mb120225_01

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