WoRMS source details

Glasby, Christopher J.; Schroeder, Paul C.; Aguado, Maria Teresa. 2012. Branching out: a remarkable new branching syllid (Annelida) living in a Petrosia sponge (Porifera: Demospongiae). Zoological Journal of the Linnean Society 164(3): 481-497.
World Polychaeta Database (WPolyD)
We describe the morphology and biology of a previously unknown form of branching annelid, Ramisyllis multicaudata gen. et sp. nov., an endosymbiont of shallow-water marine sponges (Petrosia sp., Demospongiae) in northern Australia. It belongs to the polychaete family Syllidae, as does Syllis ramosa McIntosh, 1879, the only other named branching annelid, which was collected from deep-water hexactinellid sponges during the 1875 Challenger expedition. It differs from S. ramosa in parapodial and chaetal morphology. Ramisyllis multicaudata gen. et sp. nov. has segments of several types, including specialized posterior segments on the emergent portions of the worm, and simplified elongate segments that bridge larger cavities in the sponge interior. Aside from the obvious branching form, the new annelid is similar to Parahaplosyllis, differing from it in lacking pharyngeal armature and in the details of the parapodial chaetae and dorsal cirri. Molecular evidence from 16S and 18S rDNA supports a sister-group relationship with Parahaplosyllis, with both being sister to Trypanosyllis and Eurysyllis. The phylogenetic position of R. multicaudata gen. et sp. nov. indicates that branching has evolved independently in Ramisyllis gen. nov. and Syllis. This is supported by differences in the branching process between the two taxa: in S. ramosa branching is initiated by segment addition at the parapodium, whereas in R. multicaudata gen. et sp. nov. segments are added from a region between parapodia. A model for branching in R. multicaudata gen. et sp. nov. is proposed and possible developmental processes underlying branching in Annelida, and body symmetry comparisons with other invertebrates, are also discussed.
2013-01-12 18:30:12Z

Holotype NTM W23745, geounit Darwin Harbour, identified as Ramisyllis multicaudata Glasby, Schroeder & Aguado, 2012

Aguado et al (2015) discovered 18S molecular sequences in Glasby et al (2012) were contaminated, and, using new ... [details]

 Depth range

Low water spring tide level to at least 20 m. [details]


Coastal waters of the ‘Top End’ of northern Australia. [details]

 Editor's comment

Corrected to Lumbrinereis. Was incorrectly listed under Lumbricus auctorum. [details]


Named derived from the Latin, ramus, masculine, meaning branch. [details]


Name derived from the Latin, multus for many, and caudata, feminine, for tailed. [details]


An endosymbiont of Petrosia sp. sponges (purple and white forms), in depth range from low water spring tide to at ... [details]

 Type locality

Channel Island, Darwin Harbour, Australia, about 200 m north of bridge, 12° 33.2' S, 130° 52.4' E (-12.553333° ... [details]