On some species of Chone Krøyer, 1856 (Polychaeta: Sabellidae) from world-wide localities
Author
Tovar-Hernández, María Ana
text
Zootaxa
2007
1518
31
68
journal article
10.5281/zenodo.177378
5e8514d7-6ee6-4d28-ba68-931864d4b0e6
1175-5326
177378
Chone kroyerii
Sars, 1862
Figure 8
Chone
kr
ø
yerii
Sars, 1862
: 35
–37.—
Cochrane, 2000
: 144
–145.
Material examined.
Non-type material
.
Bogestr
Ø
mmen
[
ZMO
] (1).
Additional material
.
Chone duneri
Malmgren, 1867
[
ZMUC
POL
–1755,
Norway
].
Chone infundibuliformis
Kr ø
yer, 1856 [
ZMUC
POL
–1749,
paralectotype
].
Description.
Colour
,
body shape
,
and size
. Body cream-coloured, no branchial crown. Trunk cylindrical. Body length
24 mm
, width
0.4 mm
. Tube unknown.
Branchial lobes and branchial crown
. Insertion of the branchial crown not exposed beyond collar (
Fig. 8
B).
Peristomium
. Anterior peristomial ring lobe (
aprl
) not exposed beyond collar, distally entire, triangular (
Fig. 8
B). Posterior peristomial ring collar: antero-dorsal, ventral and lateral margins entire, ventral margin higher than dorsal (
Fig. 8
D); longitudinal grooves on dorsal side of collar; entire length of mid-dorsal collar margins forms a broad gap (
Fig. 8
B). Dorsal pockets well developed. Ventral shield of collar rectangular (not easily discernible). Ratio of posterior peristomial ring collar length
versus
chaetiger 2 length, in lateral view: 2:1.
FIGURE 8.
Chone kroyerii
. (A) Anterior end, ventral view; (B) same, dorsal view; (C) spermatozoon; (D) body, lateral view; (E–G) paleate chaetae; (H) bayonet chaeta; (I) very long, posterior abdominal chaeta; (J) thoracic uncinus; (K) anterior abdominal uncinus; (L) posterior abdominal uncinus. (A–B, D) Methyl green staining. (A–L) [ZMO Boūgestrommen].
Thorax
. Chaetigers 2 to 8: notopodia– two irregular rows of elongate, narrowly hooded chaetae; one anterior row with narrow bayonet chaetae (
Fig. 8
H); two posterior rows with symmetrical; paleate chaetae with a medium-sized mucro (
Figs 8
E–G); neuropodia– two irregular rows of acicular uncini per torus, main fang surmounted by three rows of teeth (
Fig. 8
J), second tooth enlarged, located in the midline, dentition covering one quarter of the main fang length. Glandular ridge on chaetiger 2: narrow.
Abdomen
. Abdominal segments: 51. Anterior abdominal uncini with the main fang surmounted by five rows of teeth equal in size (
Fig. 8
K), occupying less than half the length of main fang, main fang not extending beyond breast, breast rectangular. Posterior abdominal uncini with four rows of teeth equal in size (
Fig. 8
L). Very long, narrowly hooded chaetae (
Fig.
8
I). Pygidium with triangular posterior margin (
Fig. 8
D).
Gametes
.
Male
with spermatozoa in thorax and abdomen: acrosome elongate, triangular, nucleus barrelshaped, two rounded mitochondria (
Fig. 8
C).
Methyl green staining
. Collar dorsal and lateral surfaces completely stained (
Figs 8
B, D), collar ventral surface coloured only the base of the ventral collar shield (
Fig. 8
A), other areas with small dark points. Thorax dorsally less stained than ventrally (
Fig. 8
B).
Remarks.
Sars (1862)
stated that the specimens resembled
Chone paucibranchiata
(Kr ø yer, 1856) to such an extent that he was long predisposed to assume that taxon; however, the number of radioles is not a character to differentiate species and the biannulate condition in thoracic segments is a common pattern in
Chone
.
Chone kroyerii
was referred to
C. infundibuliformis
by
Malmgren (1866)
and
Fauvel (1927)
, but
Cochrane (2000)
recognized this taxon as valid.
Chone kroyerii
,
C. duneri
and
C. infundibuliformis
have anterior and posterior abdominal uncini with similar shape (not modified);
C. kroyerii
and
C. infundibuliformis
have the branchial lobes not exposed beyond collar (exposed in
C. duneri
);
C. kroyerii
has a broad collar gap (narrow in
C. infundibuliformis
), and the ventral margin of collar higher than
C. infundibuliformis
. Among species of
Chone
included in this revision,
C. kroyerii
is unique by having a rectangular ventral shield of collar (
Table 2
).