Streptosyllis aequiseta Hartmann-Schröder 1981

Rank:

Species

Type taxon:

Synonyms:

Species description:

Streptosyllis aequiseta, anterior part
Holotype with 26 chaetigers, length 1.7mm. Greatest width without parapodia 0.21mm. No pigmentation. Body surface smooth, without papillae. Prostomium wider than long, anterior margin slightly convex. Four relatively large eyes in trapezoid arrangement, on each side two eyes close to each other. Palps reduced to minute papillae on the ventral side of the prostomium, not visible from dorsal. Median antenna broken, probably club-shaped, inserted on small ceratophore in the middle of the prostomium. Lateral antennae inserting near anterior margin of prostomium, club-shaped, shorter than prostomium, also on small ceratophore. First segment clearly separated from prostomium, following segments not clearly separated. Tentacular cirri in shape and length similar to lateral antennae. Dorsal cirri in first 2 chaetigers club-shaped, on first chaetiger about as long as the width of the segment, on the 2nd chaetiger half this length.

Streptosyllis aequiseta, posterior parapod

Following dorsal cirri more filiform, distally not thicker than proximal, no real differences in length, posteriorly slightly shorter. Maximal length: a bit longer than half the segments' width. No articulation, at most slightly wrinkled. Ventral cirri slightly shorter than dorsal cirri, also filiform, posteriorly becoming longer, always longer than parapodial lobe. Parapodia bluntly conical.

Streptosyllis aequiseta, aciculae, anterior parapodia A single acicula per parapodium, distally knobbed, in chaetigers 2-6 enlarged and more than twice as thick as in the other segments.

Streptosyllis aequiseta, upper compound chaetae, anterior parapod Streptosyllis aequiseta, lower compound chaetae, anterior paprapod

1st to 6th chaetiger with 1-3 compound chaetae with long blades and 7-11 chaetae with short blades. Short blades shaped like the long ones, serrated and distally bifid.

Streptosyllis aequiseta, compound chaetae, posterior parapod

After chaetiger 6 number of compound chaetae per parapod reduces gradually to 5 posteriorly. Shaft of compound chaetae distally with 3-4 differently sized teeth.

Streptosyllis aequiseta, dorsal simple chaetae, posterior parapod Streptosyllis aequiseta, simple dorsal chaeta, detail of tip

Single dorsal chaeta from chaetiger 1, subdistally on lower margin serrated, distal end blunt and covered by a half-open membrane.

Pharynx with soft papillae, without tooth. Proventriculum from chaetiger 3 through chaetiger 8, with about 47 muscular rows.

Taxonomic Remarks:

The greatest similarity can be observed with S. cryptopalpa , especially in the shape of the chaetae. S. cryptopalpa has however 6 eyes and two anterior eyspots, the palps are more filiform and the aciculae are enlarged only in chaetigers 2-5.

Source of description:

after Hartmann-Schröder G.1981. Teil 6. Die Polychaeten der tropisch-subtropischen Westküste Australiens (zwischen Exmouth im Norden und Cervantes im Süden). In: Hartmann-Schröder, G. & Hartmann, G., Zur Kenntnis des Eulitorals der australischen Küsten unter besonderer Berücksichtigung....

Source of Images:

San Martín G, Hutchings P. 2006. Eusyllinae (Polychaeta, Syllidae) from Australia with the description of a new genus and fifteen new species.

Type locality:

Exmouth: Tantabiddy Creek, Australia

Other localities:

Indian Ocean

Depth range:

shallow waters

Ecology:

Habitat: