Pauline Walsh Jacobson, USA
Info
Spirobranchus corniculatus (Grube, 1862)
Coral reefs are complex and highly productive ecosystems with the highest biodiversity in the sea. This biodiversity is dominated by invertebrates, and some of the most conspicuous invertebrates of shallow coral reefs are Christmas tree worms or calcareous tubeworms of the genus Spirobranchus. Since identifying species in this group was quite problematic, scientists used genetics to help identify them and were surprised that what appeared to be three species turned out to be just one.
The name “Christmas tree worm” refers to the spectacular, colorful cones formed from spiral-shaped branches (hence the Latin name) and is reserved for members of the genus that live in close association with large corals. The traditional way to distinguish species of Christmas tree worms was to look at the structure (the operculum) that the animals use to close the tube when they retreat into the tube. The operculum is provided with a series of calcareous spines that serve to ward off potential intruders. The problem is that the shapes are too variable to be reliable indicators of species diversity or number of species.
To answer the question of whether the shape and number of spines are suitable for recognition by these tubeworms, 90 specimens of the Spirobranchus corniculatus complex were sampled from Australia, Fiji and the Coral Triangle, the marine area that includes the waters of Indonesia and Malaysia. the Philippines, Papua New Guinea, Timor-Leste and the Solomon Islands. This species complex included three morphologically defined species, Spirobranchus corniculatus, Spirobranchus cruciger and Spirobranchus gaymardi. Scientists examined the variability of both nuclear and mitochondrial genes in 2015 to test whether the complex includes three genetically distinct lineages identified by their opercula, or tube plugs.
To our surprise, molecular data revealed that the three-morphospecies Spirobranchus corniculatus complex is actually a single, morphologically variable species that lives throughout the central Indo-Pacific.
Synonymised names
Cymospira brachycera Baird, 1864 · unaccepted (subjective synonym)
Cymospira crescentigera Quatrefages, 1866 · unaccepted (subjective synonym)
Cymospira gaymardi Quatrefages, 1866 · unaccepted (subjective synonym)
Cymospira macgillivrayi Baird, 1864 · unaccepted (subjective synonym)
Cymospira morchii Quatrefages, 1866 · unaccepted (subjective synonym)
Cymospira quoyi Quatrefages, 1866 · unaccepted
Cymospira tricornis Baird, 1864 · unaccepted (subjective synonym)
Pomatoceropsis roxasi Holly, 1935 · unaccepted (subjective synonym)
Pomatoceros bucephalus Mörch, 1863 · unaccepted (subjective synonym)
Pomatoceros corniculata Grube, 1862 · unaccepted (superseded original combination)
Pomatoceros crucigera Grube, 1862 · unaccepted (superseded original combination)
Pomatoceros davaoensis Treadwell, 1942 · unaccepted (subjective synonym)
Pomatoceros gaymardi Pruvot, 1930 · unaccepted (subjective synonym)
Pomatoceros helicoides Marenzeller, 1884 · unaccepted (subjective synonym)
Pomatoceros luzonica (Grube, 1881) · unaccepted (subjective synonym)
Pseudopomatoceros roxasi (Holly, 1935) · unaccepted (subjective synonym)
Serpula (Pomatoceros) corniculata Grube, 1862 · unaccepted (superseded original combination)
Serpula (Pomatoceros) crucigera Grube, 1862 · unaccepted (superseded original combination)
Serpula (Pomatoceros) luzonica Grube, 1881 · unaccepted (subjective synonym)
Spirobranchus corniculus [auct. lapsus] · unaccepted (misspelling)
Spirobranchus crescentigera (Quatrefages, 1866) · unaccepted
Spirobranchus cruciger (Grube, 1862) · unaccepted (subjective synonym)
Spirobranchus gaymardi (Quatrefages, 1866) · unaccepted (subjective synonym)
Spirobranchus giganteus corniculatus (Grube, 1862) · unaccepted
Spirobranchus giganteus turbinatus Pixell, 1913 · unaccepted (subjective synonym)
Vermilia bucephala (Mörch, 1863) · unaccepted (subjective synonym)
Coral reefs are complex and highly productive ecosystems with the highest biodiversity in the sea. This biodiversity is dominated by invertebrates, and some of the most conspicuous invertebrates of shallow coral reefs are Christmas tree worms or calcareous tubeworms of the genus Spirobranchus. Since identifying species in this group was quite problematic, scientists used genetics to help identify them and were surprised that what appeared to be three species turned out to be just one.
The name “Christmas tree worm” refers to the spectacular, colorful cones formed from spiral-shaped branches (hence the Latin name) and is reserved for members of the genus that live in close association with large corals. The traditional way to distinguish species of Christmas tree worms was to look at the structure (the operculum) that the animals use to close the tube when they retreat into the tube. The operculum is provided with a series of calcareous spines that serve to ward off potential intruders. The problem is that the shapes are too variable to be reliable indicators of species diversity or number of species.
To answer the question of whether the shape and number of spines are suitable for recognition by these tubeworms, 90 specimens of the Spirobranchus corniculatus complex were sampled from Australia, Fiji and the Coral Triangle, the marine area that includes the waters of Indonesia and Malaysia. the Philippines, Papua New Guinea, Timor-Leste and the Solomon Islands. This species complex included three morphologically defined species, Spirobranchus corniculatus, Spirobranchus cruciger and Spirobranchus gaymardi. Scientists examined the variability of both nuclear and mitochondrial genes in 2015 to test whether the complex includes three genetically distinct lineages identified by their opercula, or tube plugs.
To our surprise, molecular data revealed that the three-morphospecies Spirobranchus corniculatus complex is actually a single, morphologically variable species that lives throughout the central Indo-Pacific.
Synonymised names
Cymospira brachycera Baird, 1864 · unaccepted (subjective synonym)
Cymospira crescentigera Quatrefages, 1866 · unaccepted (subjective synonym)
Cymospira gaymardi Quatrefages, 1866 · unaccepted (subjective synonym)
Cymospira macgillivrayi Baird, 1864 · unaccepted (subjective synonym)
Cymospira morchii Quatrefages, 1866 · unaccepted (subjective synonym)
Cymospira quoyi Quatrefages, 1866 · unaccepted
Cymospira tricornis Baird, 1864 · unaccepted (subjective synonym)
Pomatoceropsis roxasi Holly, 1935 · unaccepted (subjective synonym)
Pomatoceros bucephalus Mörch, 1863 · unaccepted (subjective synonym)
Pomatoceros corniculata Grube, 1862 · unaccepted (superseded original combination)
Pomatoceros crucigera Grube, 1862 · unaccepted (superseded original combination)
Pomatoceros davaoensis Treadwell, 1942 · unaccepted (subjective synonym)
Pomatoceros gaymardi Pruvot, 1930 · unaccepted (subjective synonym)
Pomatoceros helicoides Marenzeller, 1884 · unaccepted (subjective synonym)
Pomatoceros luzonica (Grube, 1881) · unaccepted (subjective synonym)
Pseudopomatoceros roxasi (Holly, 1935) · unaccepted (subjective synonym)
Serpula (Pomatoceros) corniculata Grube, 1862 · unaccepted (superseded original combination)
Serpula (Pomatoceros) crucigera Grube, 1862 · unaccepted (superseded original combination)
Serpula (Pomatoceros) luzonica Grube, 1881 · unaccepted (subjective synonym)
Spirobranchus corniculus [auct. lapsus] · unaccepted (misspelling)
Spirobranchus crescentigera (Quatrefages, 1866) · unaccepted
Spirobranchus cruciger (Grube, 1862) · unaccepted (subjective synonym)
Spirobranchus gaymardi (Quatrefages, 1866) · unaccepted (subjective synonym)
Spirobranchus giganteus corniculatus (Grube, 1862) · unaccepted
Spirobranchus giganteus turbinatus Pixell, 1913 · unaccepted (subjective synonym)
Vermilia bucephala (Mörch, 1863) · unaccepted (subjective synonym)
