Ehlers, 1897 : 94
Ehlers, 1900 : 217
Mesnil & Caullery 1898 : 142
Hartman 1953 : 38
Rozbaczylo 1985 : 132
Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America
Blake, James A.
Zootaxa
2017
4218
1
1
145
6P8WK
Ehlers, 1897
Ehlers
1897
[151,557,1268,1294]
Polychaeta
Orbiniidae
Leodamas
Animalia
67
68
Annelida
species
cirratus
Aricia cirrata Ehlers, 1897: 94–95, pl. 6, figs. 148–149. Aricia ohlini Ehlers, 1900: 217–218; 1901: 167–169, pl. 21, figs. 9–13. New synonymy. Scoloplos( Scoloplos) cirratus: Mesnil & Caullery 1898: 142. Scoloplos( Leodamas) cirratus: Hartman 1953: 38; 1957: 290; 1966: 11, pl. 2. Scoloplos( Leodamas) ohlini: Rozbaczylo 1985: 132.
Materialexamined. Argentina, offshore, 190 kmE Puerto San Julien, Santa Cruz, about 280 kmNW of Falkland Islands, 49°35′S 64°43′W, 127 m, holotypeof Arica cirrata( ZMH V1224); R/V VemaSta. V-17-86, SE of Camarones, 225–227 m, 11 Jun 1961(4, LACM-AHF Poly 5034); R/V VemaSta. V-18-12, continental slope E of Deseado, 424–428 m(2, LACM-AHF Poly 5030).— Argentina, nearshore, IBM Sta. Mej- 12, 24 m(1, JAB); IBM Sta.H- 17, 16 m(1, USNM1013659); IBM Sta. N-1055, 92– 96 m(1, SEM stub, USNM 1013663); San Antonio Oeste, Marejada Norte(1, USNM1013661); Golfo San Matías, Piedra Coloradas, Feb 1972, coll. Escofet and J.M. Orensanz (2, USNM 1013660); IBM Sta. Mej-12 (1, USNM 1013662).— Falkland Islands, Port William, 3 Sep 1902, Swedish Antarctic Expedition 1901–1903, Sta.52, 51°40'S; 57°44'W, 17 m, in sand (1, SMNH3106); Port Stanley, 9 Apr 1927, coll. W.S. Schmidt (1, USNM 24341).— Chile, Straitsof Magellan, EltaninSta. 7-967, 81 m(1, USNM56465). — Tribune Bank, 52°38′S, 70°00′W, 46 m, sand and gravel, coll. E. Nordenskold, holotypeof Aricia ohlini( SMNH551). — South Orkney Islands, EltaninSta. 12-1079, 593– 598 m(1, USNM56467).
Description. Holotype(ZMH V1224) incomplete, 24 mmlong, 1.5 mmwide for 73 setigers; thoracic region narrow, with 27 setigers, flattened at first, becoming more rounded in abdominal region. Falkland Islandsspecimen (SMNH 3106) incomplete, about 17 mmlong and 1.5 mmwide for 54 setigers; thoracic region narrowing anteriorly, slightly depressed, with 32 setigers, last four setigers increasingly smaller, with fewer uncini. Tribune Bank specimen (SMNH 551) also incomplete, 17 mmlong and 1.5 mmwide for 47 setigers; thoracic region with 21 setigers. Color in alcohol: brown. Prostomium triangular in outline, tapering anteriorly, but not acutely pointed; without eyespots; multi-lobed proboscis present ( Fig. 30A); paired nuchal organs present dorsolaterally at border with peristomium ( Fig. 29D, inset). Peristomium with one well-developed achaetous ring distinctly separated from prostomium and first setiger ( Figs. 29D, 30A). Notopodial postsetal lobes from setiger 1, short, fingerlike at first, then increasing in length, becoming cirriform by setigers 4–5 ( Figs. 29D, 30B), continuing through abdominal segments. Thoracic neuropodia with setae arising from elongate thickened lobe; with short, conical postsetal lobe first present from middle of neuropodium from about setiger 25 or last 3–7 thoracic setigers ( Fig. 30B); with short, cirriform subpodial lobe resembling ventral cirrus first present from last 2–6 thoracic setigers, continuing posteriorly through 18–20 abdominal setigers ( Fig. 30B–C). Abdominal neuropodia with thickened elongated lobes bearing short cirriform postsetal lobe ( Fig. 30C). Thoracic and abdominal notosetae including fascicles of crenulated capillaries and 3–4 short, furcate setae; furcate setae with unequal tynes, connected by thin webbing composed of very fine needles and with smooth shaft ( Fig. 30D); with SEM fine needles between tynes numbering 7–8 on a side, merging with tynes; each tyne with expanded apex, narrowing to bluntly pointed tip, but with narrow, elongate opening on inner border of tyne ( Fig. 29H); shaft with transverse rows of minute barbs ( Fig. 29H). Thoracic neuropodial uncini arranged in three long vertical rows and one short posterior row, similar to S. marginatus( Fig. 29D–E), without accompanying capillaries; uncini blunt tipped, with weakly developed subapical notch or groove and with smooth shaft ( Fig. 30E– F); with SEM subapical groove, elongate, flattened extending about one-third distance to point of emergence from neuropodium, rest of shaft with weakly developed transverse ribs ( Fig. 29E–F); abdominal neurosetae including capillaries and an acicular spine sometimes with thin hyaline hood ( Fig. 30G), sheath not apparent in SEM ( Fig. 29G). Branchiae from setiger 6 ( Figs. 29D, 30A), each broad, basally tapering to prolonged, nipple-like extension; with lateral cilia visible ( Fig. 30B–C). Branchial bases of some abdominal segments connected with low ciliated crest. Pygidium of specimen from USNM 1013660 with anus directed posteriorly, surrounded by dorsal pair of thick lobes and four pairs of lateral cirri; dorsal most pair longest, weakly moniliform, one with bifurcate tip, other with single tapering tip; two middle pair short, stubby, sometimes one missing; ventral most pair short, narrow, tapering to pointed tip.
Remarks.The holotype was collected at a depth of ca. 125 moffshore SW Argentina and approximately 280 kmNW of the Falkland Islands. The type specimen agreed very well with Ehlers’ (1887) original account both with size, number of segments, and morphology. The Falkland Islands specimen was examined by Hartman (1953:38)who found it agreed with Ehlers (1897)original account; my examination of this specimen confirms this identification. Ehlers’ holotype is 24 mmlong for 73 segments with 27 thoracic segments; the largest specimens in the new collections are 17 mmlong for 54 segments with 32 thoracic segments. The type specimen of Aricia ohlinifrom the Straits of Magellan also agrees well with Leodamas cirratus. Leodamas cirratusclosely resembles L marginatusand L. cochleatusin the arrangement and form of the thoracic neuropodial uncini, which are arranged into four vertical rows and have grooves on one side of the tip and transverse ridges or rows of minute barbs along the shaft seen best in SEM. In L. cirratus, the uncini are not accompanied by capillaries, whereas superior capillaries are sometimes present in L. marginatus. Leodamas cirratushas a single subpodial lobe or ventral cirrus from posterior thoracic and some abdominal segments; this lobe is lacking on L. marginatus. The prostomium of L. cirratusis more acutely pointed and the anterior thoracic region is less distinctly tapered than in L. marginatus. Further, the thoracic region of L. cirratusis more dorsoventrally flattened than in L. marginatus. Differences with L. cochleatusinclude the presence of thoracic neuropodial uncini with a broad, heavily notched apex and with distinct transverse ridges on the shafts. Additionally, L. cochleatushas abdominal notopodial acicular spines in addition to neuropodial (see below). The presence of moniliform pygidial cirri appears to be unusual among orbiniids, but these have not been well studied.
Distribution.Off the SE coast of Argentina, shallow subtidal to 225–428 m; Falkland Islands 17–127 m; Straits of Magellan, 45–80 m; South Orkney Islands, 593– 598 m.
1424727926
ZMH
Argentina
127
-49.583332
Material
1103
-64.71667
67
68
1
Santa Cruz
holotype
1424727915
1986-05-17
Argentina
226
Camarones
67
68
1
Santa Cruz
holotype
1424727927
1918-05-12
Argentina
426
Deseado
67
68
1
Santa Cruz
holotype
1424727914
USNM
Sta.
Argentina
12
Argentina
67
68
USNM 1013659
1
holotype
1424727928
USNM
Marejada Norte
Argentina
Oeste
67
68
USNM 1013661
1
Oeste
holotype
1424727924
1901
1903
1901
Sta.
Falkland Islands
-51.666668
Swedish Antarctic Expedition
Port William
67
68
1
holotype
1424727929
SMNH
Falkland Islands
17
Port Stanley
-57.733334
67
68
SMNH 3106
1
holotype
1424727935
USNM
Chile
487
Magellan
Straits
67
68
USNM 56465
1
holotype
1424727930
SMNH
E. Nordenskold
Chile
46
-52.633335
Tribune Bank
1082
-70.0
67
68
SMNH 551
1
holotype
1424727921
[450,1328,1924,1949]
USNM
Chile
598
South Orkney Islands
67
68
USNM 56467
1
South Orkney Islands
holotype