Cirratulidae sp. 1
Chaetocirratulus andersenensis (Augener, 1932)
Vouchers. SEALION: stations 1MFB and 18MFB.
Diagnosis. Large species, 106mm long 10mm wide. Dorso-ventrally flattened and tapering at each end to a blunt point, body wide with crowded chaetigers, much wider than long, no obvious differentiation between thoracic and abdominal regions, dorsal groove/furrow proximally. Ridge running down mid-line in abdominal chaetigers. Rear end of body tapering sharply, pygidium simple terminal surrounded by low lobes.
Prostomium wide, with rounded free edge. Prostomium with three annulations, approximately the same size. One pair of dorsal tentacles situated laterally on the first chaetiger, lying dorsal to the notochaetae. First branchiae on chaetiger 2. Subsequent branchiae in line with first, extending down only on anterior third part of body.
Chaetae all simple capillaries arising on low buttons in anterior chaetigers. Notochaetae both long and short chaetae; long chaetae up to 9+ chaetigers in length, very thin and flexible with fine tips; short chaetae slightly thicker. Only short capillaries in neurochaetae, with fine serrations along edge; 5–6 chaetae in noto and neuropodia.
MGSP. Solid stain over the dorsal prostomium and peristomial areas; ventrally on the prostomium a band runs into the mouth; band of stain on each chaetiger, particularly strong over the parapodia area.
Remarks. Despite this species being large and in some samples common. Superficially it resembles a multi-branchiate species of Cirratulus but recent analyses by Blake (2018) have placed it in a new genus Chaetocirratulus. Blake's description of C. andersenensis agrees well with the Falkland Island specimens.
