Ampharetinae Malmgren, 1866
Anobothrus Levinsen, 1884
Anobothrus sp. 1
Voucher. Sea Lion: station 7MFC
Diagnosis. Voucher is a complete specimen, 7.5mm long and 0.5mm wide. Thorax consists of paleae bearing segment and 14 chaetigers, 12 of these uncinigers; abdomen with 12 uncinigers. Whitish, circular band anterior to notopodia of TU-2 (stains strongly red using Shirla stain), additionally stain shows ventral only band on TU-1. First and second notopodia reduced, the modified notopodia on TU-8 slightly shifted dorsally and connected with low glandular ridge.
Prostomium Ampharete-type, trilobed, without glandular ridges. Paleae present, about 15 per fascicle, longer than most developed notochaetae, pale yellow in colour, flat, stout, 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 tightly attached posteriorly to innermost and median pair; styles of branchiae missing; all branchiophores of equal size.
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 shortened chaetae; in modified notopodia of TU-8 limbate notochaetae similar, but tapering into very long, thin tip. Thoracic uncini, tiny; abdominal uncini with 7 (5 large and two distalmost very small) teeth in lateral view. Abdominal segments without rudimental notopodia or neuropodial cirri. Pygidium a small, narrow cone, 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. Only two species know from the region share a character of circular band anterior to TU-2, both deep-water species. Of these, A. rubropalaetus differs in possessing long, red paleae (colour visible even in preserved specimens) while A. wilhelmi has all 4 pairs of branchiae arranged in single row, with two outermost pairs reduced in size. Outside the geographical area only deep-water, boreal species A. laubieri has circular band anterior to TU-2, but it only possesses 3 pairs of branchiae. Falkland Island specimens currently assigned morphospecies Anobothrus sp. 1 represent new species and will be formally described.
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 |
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