First live records of the ruby seadragon (Phyllopteryx dewysea, Syngnathidae)

Greg W Rouse,Josefin Stiller,Nerida G Wilson

doi:10.1186/s41200-016-0102-x

Abstract

Until recently, only two species of seadragon were known, Phycodurus eques (the leafy seadragon) and Phyllopteryx taeniolatus (the common seadragon), both from Australia. In 2015, we described a new species of seadragon, Phyllopteryx dewysea (the ruby seadragon). Although the leafy and common seadragons are well known and commonly seen in aquarium exhibits world-wide, the ruby seadragon was known only from four preserved specimens, leaving many aspects of its biology unknown. Based on specimen records, it was speculated that the ruby seadragon normally lives at depths beyond recreational SCUBA diving limits, which may also explain why it went undiscovered for so long. The ruby seadragon also bears a superficial resemblance to the common seadragon, with a number of specimens misidentified in museum collections. The only recent live-collected specimen was trawled from the Recherche Archipelago, a cluster of over 100 islands in Western Australia. We took a small remotely operated vehicle (miniROV) to this locality to obtain the first images of live ruby seadragons. We made observations on the seadragon habitat and behavior, including feeding. We also provide new key observations on their morphology, notably that they lack dermal appendages and have a prehensile tail. We recommend that the ruby seadragon be protected as soon as practicable.

Highlights

The original description of the ruby seadragon (Phyllopteryx dewysea, Stiller, Wilson and Rouse 2015) was based on four specimens, three from near Perth in Western Australia
Our observations on living ruby seadragons, as well the specimens either trawled (Stiller et al 2015) or washed ashore (Della Vedova 2015), including a male with a brood of young, suggest there is a viable population in the vicinity of the Recherche Archipelago
The earlier records from further west (Stiller et al 2015) suggest the ruby seadragon may have a widespread distribution in Western Australia, though there is little contemporary evidence to support this

Summary

Introduction

The original description of the ruby seadragon (Phyllopteryx dewysea, Stiller, Wilson and Rouse 2015) was based on four specimens, three from near Perth in Western Australia. One of these had been collected in 1919 as a beach-washed specimen and the other two were trawled from 72 m in 1956. The museum specimens of ruby seadragons possessed the enlarged bony spines to which these appendages attach in the other species, the appendages themselves were absent It was not clear if the appendages had been lost postmortem. To obtain the first live observations of the ruby seadragon, we went to the Recherche Archipelago in Western Australia in early April 2016

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Conclusion