Meet Melita panda: The black-and-white crustacean shrimp

In the 1990s, a Japanese scientist, Shigeyuki Yamato, noticed an unusual species of shrimp swimming around in local intertidal waters. It was striking because it had unique black-and-white coloration, similar to the coat of the iconic giant panda.

Decades later, this new species has been officially named and introduced to science as Melita panda, the newest melitid amphipod. Its recognition highlights the importance of dedicated research and the fact that marine biodiversity still holds many surprises for those who look carefully.

The journey of crustacean discovery

Before its unique coloring gave the Melita panda its name, there were already 63 recognized species of Melita amphipods, with 16 of them found in Japan.

Researchers Ko Tomikawa, from Hiroshima University’s Graduate School of Humanities and Social Sciences, and Hiroyuki Ariyama, from the Osaka Museum of Natural History, returned to the intertidal waters of Wakayama Prefecture where the original specimen had been found.

There, they collected significant numbers of the black-and-white amphipods for detailed morphological and genetic analyses. These studies confirmed that the small, shrimp-like crustacean is indeed a new species.

The researchers suggest that there may be many more unidentified and undescribed species of Melita amphipods in Japan’s coastal waters.

“Study on the amphipod Crustacea in the coastal zone of Japan is lagging behind,” said Tomikawa.

“In order to accurately assess species diversity, taxonomic studies are necessary. We hope the discovery of a new species of amphipod with the familiar coloring of the panda pattern will increase the public’s interest in biodiversity and taxonomy.”

Melita panda: A tribute to species taxonomy

In reality, our understanding of the world’s species diversity, especially in marine ecosystems, is still in its infancy. Identification is an essential step in understanding the biological and conservation needs of species all over the world.

“Despite the fact that biodiversity conservation is a global issue, species diversity and other aspects of biodiversity are still not fully understood,” said Tomikawa.

“As a first step toward species conservation, we conducted a taxonomic study of amphipod Crustacea, which boasts high species diversity around Japan.”

Understanding Melita panda

The researchers conducted detailed morphological studies of the physical characteristics of body parts in the crustacean to ascertain their differences from other melitid amphipods.

Unlike other familiar crustaceans, M. panda individuals are very small. The first male specimen collected was a mere 0.2 in (6 mm), with females being even smaller.

The panda-like pattern was found to consist of black markings on a body that was white. The antennae, sides, head and posterior abdomen were all black, while the rest of the body was white.

Distinctive differences in Melita panda

The researchers also used nuclear and mitochondrial genes for phylogenetic analysis, hoping to gain deeper insights into the species’ evolutionary relationships with other crustaceans and how it fits within the broader family tree.

Melita panda was found to be closely related to two other Melita amphipods, namely M. nagatai and M. koreana.

What clearly sets Melita panda apart from the other two species, however, are its distinctive coloring and its physical differences.

Melita panda boasts unique gnathopods – claws extending from the second thoracic segment – that are positioned more forward than in the other Melita amphipods.

It also features unique setae – bristles that look like hairs. These three species together form a monophyletic group, meaning that they share a common evolutionary ancestor, M. hoshinoi.

What lies ahead for crustacean research

As the researchers continue to study this newest Melita, they’re optimistic about what lies ahead.

“Hopefully, a detailed study of the ecology and behavior of Melita panda will reveal the reason for its panda pattern,” said Tomikawa.

But, the research doesn’t end with Melita panda. Tomikawa noted that further taxonomic studies on amphipods in uninvestigated areas are expected to lead to the discovery of additional new species.

“Continued taxonomic studies are expected to elucidate the biodiversity in the coastal environments of the Japanese archipelago and provide important basic data for species conservation.”

These discoveries remind us of just how much we have yet to learn about the biodiversity that surrounds us.

The study was published in the journal ZooKeys.

Image Credit: Ko Tomikawa/Hiroshima University

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