New species of Chaetozone and Tharyx (Polychaeta: Cirratulidae) from the Alaskan and Canadian Arctic and the Northeastern Pacific, including a description of the lectotype of Chaetozone setosa Malmgren from Spitsbergen in the Norwegian Arctic
Author
Blake, James A.
text
Zootaxa
2015
3919
3
501
552
journal article
10.11646/zootaxa.3919.3.5
12e779cb-148a-4853-ac3f-affef036a340
1175-5326
234051
743AF37E-54B4-4BCB-A3E8-93092F779A20
Key to 21 species of
Chaetozone
from the Northeastern Pacific and North American Arctic and Subarctic
(Reference code: 1,
Blake 1996
; 2, Blake 2006; 3, this paper. Note:
Chaetozone gracilis
Moore, 1923
and
C. armata
Hartman, 1963
, both redescribed in
Blake [1996]
are rare species not included in this key; both lack posterior cinctures and may belong to other genera. MG = Methyl Green).
1A. Paired dorsal tentacles on posterior margin of peristomium shifted posteriorly over anterior setigerous segments.......... 2
1B. Paired dorsal tentacles on posterior margin of peristomium or anterior achaetous segment, not shifted posteriorly over setiger- ous segments......................................................................................... 4
2B. Dorsal tentacles shifted dorsally over setiger 1............................................................... 3
2B. Dorsal tentacles shifted dorsally over setigers 4‒7; with distinct MG staining pattern.........................
C. bansei
1
3A. With distinct achaetous segment preceding setiger 1, bearing first pair of branchiae; all spines in posterior cinctures unidentate; no MG staining pattern.....................................................................
C. careyi
n. sp.
3
3B. Without distinct achaetous segment preceding setiger 1, first pair of branchiae on setiger 1; ventral-most spine in posterior neu- ropodia of cinctures bidentate; with distinct MG staining pattern.........................................
C. lunula
1
4A. Posterior noto- and neuropodial spines with sharply pointed with recurved tip extending posteriorly and fused with shaft form- ing blunt tip.......................................................................................... 5
4B. Posterior noto- and neuropodial spines sharply pointed or blunt, not with recurved tip............................... 7
5A First pair of branchiae on setiger 1; no MG pattern...............................................
C. commonalis
1
5B. First and second pair of branchiae both on setiger 1........................................................... 6
6A. Posterior spines from posterior third of body, or about setiger
65 in
neuropodia and setiger
70 in
neuropodia; dorsal longitudi- nal groove absent; with thin ridge along ventral midline; posterior cinctures well developed, with 26‒29 spines on a side, over-
lapping at dorsal midline of each cincture; MG staining prostomium and peristomium, but with clear unstained curved dorsal band between at posterior margin of prostomium....................................................
C. allanotai
2
6B. Posterior spines from middle body segments, or setigers
30‒40 in
neuropodia and
40‒45 in
notopodia; shallow dorsal groove from anterior through middle segments, absent posterior segments; ventral groove in middle segments; posterior cinctures well developed, with 20‒23 spines on a side; MG on tip of prostomium and last two peristomial rings......
C. camasetosa
n. sp.
3
7A. With distinct achaetous segment between peristomium and setiger 1, may be partially fused to setiger 1................. 8
7B. Without distinct achaetous segment between peristomium and setiger 1.......................................... 15
8A. Achaetous segment bearing both first pair of branchiae and dorsal tentacles........................................ 9
8B. Achaetous segment bearing only first pair of branchiae; dorsal tentacles arising from peristomium or notch at posterior margin................................................................................................... 10
9A. Body with distinct enlargement (stomach) between esophagus of thoracic segments and intestine of abdominal segments, this imparting characteristic shape to body; with brown pigment over most of body, concentrated in anterior segments; posterior cinctures well developed, with 16‒18 spines on a side; no MG pattern evident............................
C. brunnea
2
9B. Body without distinct morphological enlargement except for segments sometimes swollen with gametes; pigment absent; posterior cinctures well developed, with 15-17 spines on a side; MG pattern on prostomium, peristomium, and anterior parapodia; peristomium with two prominent annulations anterior to achaetous segment separated by deep grooves, first annulation inflated, twice size of second............................................................
C. malmgreni
n. sp.
3
10A. Neuropodial spines from setiger 50–70 or greater in middle body segments, in middle body segments; spines arranged in partial or complete cinctures; MG staining pattern present or absent............................................... 11
10B Neuropodial spines from setiger
5‒40 in
anterior third of body; spines arranged in partial or complete cinctures; MG staining pattern present or absent............................................................................... 12
11A. Neuropodial spines from setiger 70 or greater; posterior cinctures partial, with up to 14 spines on a side; peristomium not overlain with dorsal crest; MG stains prostomium and peristomium intensely, except for tip of prostomium and dorsal surface of peristomial annulations; parapodia with weak stripes across dorsum and venter...........................
C. hedgpethi
1
11B. Neuropodial spines from setiger 50‒53; cinctures with 17‒19 spines on a side; peristomium overlain with prominent crest; no MG pattern.........................................................................
C. pugettensis
,
n. sp.
3
12A. Posterior cinctures with 20‒22 unusually long, broad, flattened, pointed noto- and neuropodial spines on a side, without accompanying capillaries; with MG pattern..........................................................
C. palaea
2
12B. Posterior cinctures with thick, rounded noto- and neuropodial spines, pointed or blunt-tipped, with accompanying and alternating capillaries....................................................................................... 13
13A. Some anterior capillaries sometimes with splayed fibrils; other capillaries from setiger 40‒45 short, an oblique edge with fibrils, tapering to pointed tip; with posterior cinctures greatly reduced to only 8 spines on a side, each with thin fringe along convex side; neuropodial spines from setiger 18‒40; no MG pattern........................................
C. acuta
1
13B. Fibrils not conspicuous on capillaries; posterior cinctures reduced or complete, but with 13 or more spines on a side...... 14
14A. Body heavily pigmented with numerous brown to black pigment speckles over entire body; with a prominent mid-ventral ridge line along entire length of body formed of ventromedial bulges arising from each segment; with weak mid-dorsal groove in middle body segments; neuropodial spines from setigers 5–26; posterior cinctures reduced, with 13‒19 spines on a side; no MG pattern..........................................................................
C. pigmentata
n.sp.
3
14B. Body with anterior segments with diffuse black pigment, not discrete speckles, limited to certain areas of the body, not all over; ventral ridge low, not conspicuous; posterior cinctures well developed, with elevated membranes with 20‒22 spines on a side; with distinct MG staining pattern, with all of prostomium except tip staining, with most of peristomium staining forming “mask” over the head region...............................................................
C. bathyala
n.sp.
3
15A. Neuropodial spines from setiger 1................................................................
C. corona
1
15B. Neuropodial spines from setiger 20 or later................................................................ 16
16A. Neuropodial spines from setiger 21‒40................................................................... 17
16B. Neuropodial spines from setiger 65 or later................................................................ 19
17A. Posterior notopodial spines typically longer, narrower and pointed than heavier, blunt-tipped neuropodial spines, forming partial cinctures........................................................................................ 18
17B Posterior notopodial and neuropodial spines both similar, curved with smooth shafts and pointed tips; fully developed cinctures with 17‒19 spines on a side; with MG.......................................................
C. hobsonae
n.sp.
3
18A. Posterior spines in partial cinctures, 8‒10 spines on a side; with 4‒5 long, narrow, straight, blunt-tipped notopodial spines and 4‒5 short, thick, curved, neuropodial spines having short serrations on convex side of curved tip; with MG staining..................................................................................................
C. hartmanae
1
18B. Posterior spines in partial cinctures, 16‒18 spines on a side; posterior notosetae spinous with sharp tips; posterior neurosetae becoming shorter, forming blunt-tipped spines; no MG staining pattern..................................
C. spinosa
1,2
19A Neuropodial spines from mid-body segments, setigers 58‒65; MG staining present or absent......................... 20
19B. Neuropodial spines from posterior third of body, setigers 105‒120; posterior cinctures partially developed, with 11‒12 spines on a side; MG stains with distinctive pattern.....................................................
C. columbiana
1
20A. Neuropodial spines from setiger 65‒80; posterior cinctures weakly developed, with 8‒9 spines on a side; with weak MG reaction........................................................................................
C. senticosa
1
20B Neuropodial spines from setiger 58‒65; posterior cinctures fully developed with up to 22 spines on a side; without MG staining pattern................................................................................
C. ruffi
n. sp.
3