Character-matrix based descriptions of two new nemertean (Nemertea) species
Author
Sundberg, Per
Author
Chernyshev, Alexey. V.
Author
Kajihara, Hiroshi
Author
Kånneby, Tobias
Author
Strand, Malin
text
Zoological Journal of the Linnean Society
2009
2009-10-31
157
2
264
294
https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2008.00514.x
journal article
10.1111/j.1096-3642.2008.00514.x
0024-4082
5443728
CARININA OCHRACEA
SP. NOV.
(
FIGS 5
,
6
;
TABLE 4
)
Holotype
:
Sexually
immature, series of transverse sections
GNHM
Nemertini
83. Type locality 58°53′124″N, 11°07′275″
E. The
18S rDNA sequence of the species has been deposited with
GenBank
(accession number
EU495306
) together with sequences of the mtDNA
COI
gene (accession number
EU489492
).
Further material:
Mud and soft bottom, depth from
5 m
and down to
40 m
.
All
in the
Koster area
.
External characters (
Fig. 5
):
The specimen was
13–15 mm
long and about
1 mm
wide. The body is of more or less uniform width slightly narrowing towards the bluntly rounded posterior tip. The head, which is bluntly rounded, is not wider than the rest of body but sometimes demarcated by a small neck. Posterior half of body yellowish orange with a pronounced transition to orange of anterior half. Lateral margins thin and with same colour as body. Head orange as the anterior part but with reddish touch on margins. Dorsally, the head possesses shallow longitudinal furrows that might be broken, eyes are absent. Proboscis pore subterminal and lies in a small triangular pit on the foremost ventral tip of the head. The mouth, situated further back, is surrounded by wrinkled lips. Individual specimens are slow moving and when mechanically disturbed they first back up and when touched several times they coil in a spiral moving head back and forth. When specimens were fixed they contracted strongly.
Figure 3.
Raygibsonia bergi
gen.
et
sp. nov.
Drawing by Helena Samuelsson, The Encyclopedia of the Swedish Flora and Fauna.
Internal characters:
Figure 6
,
Table 4
, and Appendix.
Systematic discussion:
We have chosen to place this new species in the genus
Carinina
based on the two synapomorphies: (1) brain and lateral nerve cords situated in epidermis; (2) longitudinal muscle plate
Figure 4.
A–F,
Raygibsonia bergi
gen.
et
sp. nov
. A, section through anterior-most part of body showing cephalic glands, cerebral organs, oesophagus, and the poorly developed precerebral septum. B, section through cephalic region showing cephalic blood supply, stomach, and cerebral ganglia. Note the vascular plug (arrowhead). C, section through pyloric region showing the connection between pylorus and intestine. Note the myofibrillae in the lateral nerve cord (arrowhead) and the nerves of the proboscis (arrow). D, section through proboscis armature region of body showing the stylet apparatus. Note the accessory stylet (arrow) and the peripheral neural sheath (arrowhead) that connect the proboscis nerves. E, section through gonad region of body showing immature gonads (probably sac-like). Note the accessory lateral nerve (arrowhead). F, section through stomach region of body, showing distribution of gland cells. Abbreviations: AP, accessory stylet pouch; AN, accessory lateral nerve; CB, cerebral ganglion; CC, cerebral canal; CF, cephalic furrow; CG, cephalic glands; CL, dorsal lobules of cephalic glands; CM, circular muscle layer; CO, cerebral organ; D, dermis; DC, dorsal commissure; DG, dorsal ganglion; E, epidermis; ECF, cephalic gland encircling the foregut; G, gonad; I, intestine; IC, intestinal caecum; LD, lateral diverticula; LM, longitudinal muscle layer; LN, lateral nerve cord; LV, lateral blood vessel; MDV, mid-dorsal vessel; OE, oesophagus; P, proboscis; PE, proboscis epithelium; PN, proboscis nerve; PS, precerebral septum; PY, pylorus; R, rhynchocoel; RM, retractor muscle; S, stomach; SB, stylet basis; VG, ventral ganglion.
Table 4.
Descriptions of the two species
Carinina ochracea
sp. nov
.
and
Raygibsonia bergi
gen
. et
sp. nov
. Character numbers refer to the Appendix
Table 4.
Continued
|
Carinina
|
Raygibsonia
|
| Character |
ochracea
|
bergi
|
Figure |
| 69 |
N/A |
2 |
| 70 |
N/A |
1 |
| 71 |
3 |
1? |
| 72 |
3 |
0 |
6A |
| 73 |
N/A |
1 |
4B |
| 74 |
2 |
N/A |
6B |
| 75 |
1 |
N/A |
6B–D |
| 76 |
0 |
1 |
| 77 |
N/A |
1 |
| 78 |
0 |
0 |
| 79 |
N/A |
0 |
| 80 |
1 |
N/A |
| 81 |
0 |
N/A |
6A |
| 82 |
1 |
1 |
4B |
| 83 |
0 |
1 |
4B |
| 84 |
0 |
0 |
| 85 |
0 |
0 |
| 86 |
N/A |
1 |
4C |
| 87 |
N/A |
2 |
| 88 |
0 |
N/A |
| 89 |
0 |
N/A |
| 90 |
Not seen |
Not observed |
| 91 |
0 |
0 |
| 92 |
0? |
0 |
| 93 |
0? |
1 |
4C |
| 94 |
N/A |
0 |
| 95 |
0 |
0 |
| 96 |
1 |
1 |
| 97 |
0 |
0 |
| 98 |
0 |
N/A |
| 99 |
1 |
N/A |
6D |
| 100 |
N/A |
Not seen |
| 101 |
0 |
Not seen |
| 102 |
0 |
Not seen |
| 103 |
2 |
Not seen |
| 104 |
0 |
0? |
6E, 4E |
| 105 |
0 |
0 |
| 106 |
N/A |
N/A |
| 107 |
N/A |
N/A? |
| 108 |
Not observed |
Not observed |
| 109 |
1 |
2 |
6E |
| 110 |
0 |
Not seen |
| 111 |
0 |
1 |
| 112 |
0 |
2 |
4A |
| 113 |
N/A |
2 |
4A |
| 114 |
N/A |
0 |
| 115 |
2 |
2 |
4A |
| 116 |
0 |
2 |
4A |
| 117 |
0 |
1 |
4A |
| 118 |
N/A |
0 |
| 119 |
0? |
N/A |
| 120 |
0 |
N/A |
Carinina
Raygibsonia
Character
ochracea
bergi
Figure
1 0 0
2 0 0
3 2 2
4 N/A N/A
5 0 0 & 2
6 2 Not observed
7
01
2
8 N/A 0
9 N/A 0
10 N/A 0 3
11 0 1 3
12 N/A 2 3
13 1 0 3
14 2 1 3
15 2 1 3
16 0 9 3, 5
17 N/A 0 3
18 N/A 1 3
19 N/A 1
20 N/A 0 3
21 N/A 3 3
22 6 5 3, 5
23 0 2
24 1 1
25 0 0 3
26 0 2
27 2 Not seen
28 1 N
/A 6A
29 1 N
/A
30 0 0 4, 5
31 0 3 4, 5
32 0 N
/A
33 2 0 4, 5
34 1 N
/A
35 N/A 0
36 N/A 3 4A
37 2 N
/A
38 0 0 4, 6
39 1 N
/A 6A
40 1 0 8
41 0 1 8, 4A 42 1 1
43 1 2 6B, 4C
44 0 N
/A
45 1 2
46 1 0 6C
47 0 1 4D
48 0 0
49 2 2
50 Not seen 1 4C, D 51 1 3
52 0 1 4D
53 N/A 0
54 0 2 4D
55 N/A 0
56 N/A 1
57 N/A 0 8
58 N/A 0 8
59 N/A 1 8
60 N/A 1 8
61 0 0
62 2 0
63 0 1 4A
64 N/A 2 4A
65 1? 0
66 N/A 1 4C
67 N/A 2
68 0 1
present between rhynchocoel and alimentary canal. The phylogenetic analyses in
Figures 1
and
7
do not contradict this conclusion. The genus
Carinina
is currently placed in the taxon
Palaeonemertea
, but as mentioned above the monophyletic status of the name is unsettled.
The organization of the blood system in this new species is unusual because of the presence of a precerebral unpaired cephalic blood lacuna situated dorsal and lateral to rhynchodaeum; it is randomly pierced by dorsoventral muscle bundles. Just in front of the brain the cephalic lacuna is divided into a pair of lateral cephalic lacunae, and two to three anastomosed ventral lacunae. In the mouth region two ventral lacunae form the vascular plexus, which surrounds foregut and anastomoses with two lateral vessels (lacunae). In the posterior part of the foregut region the vascular plexus disappears. In the foregut region the lateral vessels repeatedly send out branches that penetrate the rhynchocoel wall to form vascular plugs (about ten plugs on left side and about 12 plugs on right side). The only other
Carinina
species
with numerous vascular plugs is
Carinina plecta
Kajihara (2006)
.