Ampharetinae Malmgren, 1866
Anobothrus Levinsen, 1884
Anobothrus cf. glandularis Hartmann-Schröder, 1965
Voucher. Sea Lion: station 8 MFB
Diagnosis. Voucher is a complete specimen, 10mm long and 1mm wide. Thorax consists of paleae bearing segment and 14 chaetigers, 12 of these uncinigers; abdomen with 13 uncinigers. Prostomium Ampharete-type, trilobed, without glandular ridges. Paleae present, about 15 per fascicle, longer than most developed notochaetae, slender, gradually tapering into long, thin tip. Four pairs of branchiae in 3 + 1 arrangement; three anterior pairs are arranged in a row on a raised ridge, the 4th pair is stand alone, located posterior at the level of notopodia of thoracic chaetiger 2 (the chaetiger following paleae bearing segment); styles of branchiae mostly missing, where present these are long and smooth, cylindrical; branchiophores of 3 anterior pairs of equal size, branchiophore of posterior pairs, smaller, low (can be overlooked). Whitish, circular band anterior to notopodia of TU-3 (stains strongly red using Shirla stain), additionally stain shows ventral only bands on TU-1 and TU-2. First and second notopodia smaller than in subsequent chaetigers, but not reduced. The modified notopodia on TU-8 slightly shifted dorsally and connected with low glandular ridge. Notochaetae in two rows throughout the thorax, one row consist of 6-7 long, smooth, narrowly limbate capillaries and second row consists of similar, but shorted chaetae; in modified notopodia of TU-8 limbate notochaetae wider, abruptly tapering into slender tip distally (their surface may appear hirsute under high magnification). Abdominal segments without rudimental notopodia or neuropodial cirri. Pygidium a short, wide cone, dorsally slightly enlarged, no cirri observed.
Remarks. Genus Anobothrus has been a subject of recent reviews worldwide (Jirkov, 2008) and regionally concentrating on Southern Ocean and South American waters (Schüller and Jirkov, 2013), with some new species discovered in the process, many of those from deep waters. Characters of those species are summarized in Table accompanying this description. Of the 4 known species of Anobothrus known from the region, which have circular band anterior to TU-3, Falkland specimens agree with A. glandularis, although they differ in number of abdominal segments (12 in A. glandularis, 13 in Falkland specimens), but this character can show variation in other Anobothrus species (see Jirkov, 2011) and position of the posterior 4th branchiophore. Until the examination of type specimens of A. glandularis is possible to confirm the identity of Falkland specimens, we prefer to assign the name Anobothrus cf. glandularis at this stage.
Comparisons of Southern Ocean/South American species of Anobothrus
|
Size of paleae |
No. of branchial pairs and their arrangement |
CB anterior to parapodia of |
No. of TU |
No. of AU |
Other character/s |
|
|
A. patagonicus |
distinctly shorter than most developed notochaetae |
4 (3 + 1) |
TU-1 |
12 |
12 |
usually with a pair of black subepidermal spots near base of prostomial middle lobe. |
|
A. antarctica
|
much longer than most developed notochaetae |
4 (3 +1) |
TU-3 |
12 |
12 |
buccal tentacles and styles of branchiae densely papillated |
|
A. pseudoampharete |
longer than most developed notochaetae; stout, abruptly tapering distally |
4 (all in 1 row) |
TU-3 |
12 |
up to 15 |
_ |
|
A. paleaodiscus |
long, originating from a disc-like structure |
4 (3 + 1) |
TU-3 |
12 |
12 |
paleae originating from a disc-like structure |
|
A. wilhelmi |
longer than most developed notochaetae |
4 (all in 1 row) |
TU- 2 |
12 |
12-13 |
two outermost pairs of branchiae reduced size, 1st notopodia hidden under the paleae |
|
A. glandularis |
longer than most developed notochaetae |
4 (3 + 1) |
TU-3 |
12 |
12 |
paleae slender, gradually tapering |
|
A. rubropaleatus |
longer than most developed notochaetae; flat, sabre-like, abruptly tapering |
4 (3+1) |
TU- 2 |
12 |
13 |
paleae red (observable even in preserved specimens) |
|
Anobothurs sp. 1 |
longer than most developed notochaetae |
4 (3 + 1) |
TU- 2 |
12 |
12 |
paleae stout with extremely long, thin tip; pale yellow |
|
Anobothurs cf. glandularis |
longer than most developed notochaetae |
4 (3 + 1) |
TU-3 |
12 |
13 |
paleae slender, gradually tapering |
|
CB = circular band; TU=thoracic uncinigers; AU=abdominal uncinigers |
||||||