Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America
Author
Blake, James A.
text
Zootaxa
2017
4218
1
1
145
journal article
37318
10.5281/zenodo.245827
69cf893c-7b35-48e8-ad78-d9775626f287
1175-5326
245827
9345C596-8656-4B5C-AD8C-2FACF4E9240C
Orbinia
sp.
Phylo kupfferi
:
Hartman 1966
: 107
–108 (in part). Not
Ehlers, 1874
.
Material
examined.
Antarctic Peninsula South
Shetland Islands
,
Eltanin
Sta. 6-437, 267–
311 m
(1, LACM-AHF Poly 4994).
Description.
A single specimen included among USNS
Eltanin
collections from
Eltanin
Station 437 and identified by Dr. Olga Hartman, as
Phylo kupfferi
is here referred to the genus
Orbinia
because posterior thoracic modified notosetae are not present. Other specimens in the same sample are referred to
Phylo felix
(see below).
Specimen mostly complete,
0.8 mm
wide across anterior thoracic region,
7 mm
long for 35 setigerous segments. Color light tan in alcohol with no pigmentation. Anterior end of body swollen through setiger 5. Thoracic region with 12 setigers; no posterior modified thoracic segments. Prostomium short, triangular, pointed on anterior margin; nuchal organs not observed. Peristomium short and narrow. Branchiae from setiger 6. Pygidium unknown.
Thoracic notopodia short with inconspicuous cirriform lobes on setigers 1–5; with the branchiae they become long and prominent on setiger 6, continuing posteriorly. Thoracic neuropodia with a single postsetal lobe through setiger 6, increasing to 3–4 from setiger 7, becoming continuous with subpodial ventral fringe on setiger 11; ventral fringe continuing posteriorly to abdominal setiger 16. Abdominal notopodia with elongate dorsal cirrus; abdominal neuropodia flattened, rounded apically, with distinct ventral cirrus. Interramal cirri not present.
Thoracic notosetae long, camerated capillaries arranged in two rows; thoracic neurosetae with three rows of heavy, curved uncini and a posterior row of heavy camerated capillaries. Individual uncini with smooth curved tip followed by transverse ribs further down shaft; with light microscopy, evidence of sheath on side opposite transverse ribs. Abdominal notosetae consisting of 3–4 long, narrow camerated capillaries and 2–3 delicate furcate setae; furcate setae with unequal tynes with thin webbing between. Abdominal neurosetae with 1–2 aciculae, sometimes emergent, with curved blunted tips and 2–4 long, thin, simple capillaries.
Remarks.
This specimen was among a small collection from
Eltanin
Sta. 437 identified by
Hartman (1966)
as
Phylo kupfferi
, here referred to
P. felix
(see below); this single specimen is the only representative of the genus
Orbinia
reported to date from
Antarctica
and may represent an undescribed species, but due its incomplete nature and small size, it cannot be named at this time.
Distribution.
Antarctic Peninsula, South
Shetland
Islands
, 267–311.