About Syngnathus rostellatus Nilsson, 1855
The head of Syngnathus rostellatus (lesser pipefish) has a long, thin, round snout with a small up-turned mouth. Its eyes are small, positioned well back toward the gill covers. The body is long and thin, covered with bony plates. The dorsal fin sits halfway along the body, with pelvic fins located below it. The caudal fin is fan-shaped, and small pectoral fins are positioned behind the gills. Lesser and greater pipefish differ by the presence of a head crest—one species has this crest, while the other does not. Even so, the two species are still quite similar: fully grown lesser pipefish and young greater pipefish share similar coloration and markings, both have a caudal fin, and both swim in the same style. A key distinguishing feature of the lesser pipefish is a continuous black line running from the gills along the belly down to the tail, though this line is not very visible on very young specimens. The lesser pipefish is distributed in the eastern Atlantic, ranging from Norway, the British Isles, and the Bay of Biscay to western Portugal. There is a single recorded sighting of this species in the Mediterranean Sea, off Malaga, Spain, from 1981. All reported sightings from the eastern Mediterranean have been confirmed as misidentifications.