Stolephorus astrum

Stolephorus astrum, the astral anchovy, is a special kind of small fish that belongs to a group called anchovies. These tiny fish are part of a bigger family known as Engraulidae. Scientists only recently learned about this anchovy, and it lives in certain areas around Babeldaob Island in a place called Palau.

This anchovy was first found and described in 2024 by two scientists named Harutaka Hata and Hiroyuki Motomura. They studied 17 examples of the fish that they collected from coastal waters near mangroves. Because it was discovered so recently, scientists are still learning more about how this fish lives and why it is important.

Taxonomy

The astral anchovy, Stolephorus astrum, was described in 2024 in the Raffles Bulletin of Zoology. Scientists collected the fish from shallow, muddy waters in Karamado Bay and Kamiyangaru Bay on Babeldaob Island. The name "astrum," meaning "star," comes from a special star-shaped pattern on the fish's fins.

Description

Stolephorus astrum is a type of anchovy that is slim and somewhat flat on the sides. It can grow to be at least 54.8 mm long. This anchovy has special features that help scientists tell it apart from others, like a short upper jaw, certain bony plates along its body, and specific patterns of tiny dark spots on its fins.

When scientists examined dead samples of this fish, they noticed it had a light color with a faint stripe along its body and some dark spots on its head area. However, scientists do not yet know what color this fish is when it is alive.

Distribution and habitat

The astral anchovy is only found around Babeldaob Island in Palau. All the fish that scientists studied were caught in shallow, muddy waters near mangroves, where rivers flow into the sea. These waters were between about 0.6 and 15 meters deep.

Comparisons

The astral anchovy, Stolephorus astrum, shares some features with its close relatives like Stolephorus leopardus, Stolephorus pacificus, and Stolephorus teguhi. However, it has unique traits that set it apart. For example, it has fewer gill rakers, a slimmer body, a shorter fin near the front of its back, a longer tail base, and special dark spots on its chest fins. These differences help scientists tell it apart from other similar anchovies.

Etymology

The name astrum means "star" in Latin. Scientists chose this name because the fish has a pattern that looks like a star on part of its body. This pattern is made by special cells called melanophores, which are dark in color and appear on the fish's upper pectoral-fin rays.