Revision of the genus Laophontodes T. Scott (Copepoda, Harpacticoida, Ancorabolidae), including the description of a new species and a key to species
Author
George, Kai Horst
Senckenberg am Meer, German Centre for Marine Biodiversity Research DZMB, Suedstrand 44, 26382, Wilhelmshaven, Germany
kgeorge@senckenberg.de
Author
Lehmanski, Linda Maria Anne
University of Cologne, Biocenter, Zuelpicher Str. 47 b, 50674, Koeln, Germany
Author
Kihara, Terue Cristina
Senckenberg am Meer, German Centre for Marine Biodiversity Research DZMB, Suedstrand 44, 26382, Wilhelmshaven, Germany & INES Integrated Environmental Solutions UG, c / o Senckenberg am Meer - German Centre for Marine Biodiversity Research DZMB, Suedstrand 44, 26382, Wilhelmshaven, Germany
text
ZooKeys
2020
997
17
46
http://dx.doi.org/10.3897/zookeys.997.56965
journal article
http://dx.doi.org/10.3897/zookeys.997.56965
1313-2970-997-17
F7EA809BD1164D16897CCC3DDDF4DAA1
03DFE50377EB5D93A22C4275B2917531
Laophontodes volkerlehmanskii
sp. nov.
Figs 2
, 3
, 4
, 5
, 6
, 7
, 8
, 9
, 10
Locus typicus.
Indian Ocean, Central Indian Ridge, Kairei Field, station #I12_36T, geographic position
25°19.240'S
,
70°02.433'E
, 2467 m depth.
Type material.
Four females and four males collected during research cruise INDEX 2012 on December 1st, 2012. Holotype: female, not dissected, on one slide, collection number SMF 37216/1; paratype 1 (allotype): male, not dissected, on one slide, collection number SMF 37217/1; paratype 2: female, dissected and mounted onto 15 slides, collection number SMF 37218/1-15; paratype 3: male, dissected and mounted onto two slides, collection number SMF 37219/1-2; paratype 4: male, not dissected, on one slide, collection number SMF 37220/1; paratype 5: male, not dissected, on one slide, collection number SMF 37221/1; paratype 6: female, not dissected, on one slide, collection number SMF 37222/1; paratype 7: female, not dissected, on one slide, collection number SMF 37223/1.
Description.
Female
: Habitus (Figs
2A
,
3A, B
) cylindrical, body length (R to end of FR) (median value) = 399
µm
(390-405
µm
;
N
= 3). R small, fused to cphth, with 2 sensilla (one sensillum missing in Fig.
2A
) and 1 apical tube pore. Cphth reaching more than 25% of total body length, with posterior swelling on each side; dorsally covered by sensilla, those on posterior margin arising from socles. Body somites clearly distinct. Last thoracic and first abdominal somites fused forming the GDS, juncture seen as dorsal serration. Posterior margins of free body somites, excluding telson, serrated dorsally, and with sensilla arising from small socles; P2-P5-bearing somites additionally with 1 dorsal tube pore centrally; P6 and P7-bearing somites carrying 2 dorsal tube pores centrally. Telson (Figs
2A
,
3A, B
,
4A
) slightly smaller than preceding somite, with FR set widely apart. Anal operculum (Figs
4A
,
5A
) with distinct, strong apical spinules; basally with pair of sensilla and additional spines above bases of FR.
Figure 2.
Laophontodes volkerlehmanskii
sp. nov.
A
female holotype (SMF 37216/1), habitus, dorsal view
B
male paratype 1 (allotype) (SMF 37217/1), habitus, dorsal view. Scale bar 200
µm
.
Figure 3.
Laophontodes volkerlehmanskii
sp. nov. Confocal laser scanning microscopy images of
A
female paratype 6 (SMF 37222/1), habitus, dorsal view
B
female paratype 7 (SMF 37223/1), habitus, ventral view. Scale bar: 25
µm
.
FR (Figs
4A
,
5A
) slender, about 4 times as long as wide, with distal tube pore and 7 bare setae: seta II dorsal to, and twice as long as I; III subapical; IV and V apical and fused at base, V very long and narrow, distal 1/3 bipinnate; VI apical on inner margin, bare and short; VII dorsal, tri-articulated.
Figure 4.
Laophontodes volkerlehmanskii
sp. nov. Three-dimensional representation (Drishti software) based on confocal laser scanning microscopy images of Female paratype 6 (SMF 37222/1)
A
anal operculum, dorsal view; Confocal laser scanning microscopy images of male paratype 4 (SMF 37220/1)
B
A1, ventral view
C
male paratype 4 (SMF 37220/1), A1, dorsal view, numbers refer to antennular segments Scale bar: 400
µm
(
A
); 25
µm
(
B, C
).
A1 (Fig.
5B, B
') 5-segmented. First segment carrying 1 bipinnate seta and 2 rows of spinules on apical edge below seta; second segment with 9 setae (2 setae broken in Fig.
5B
) and 1 row of spinules each on outer and inner margin; third segment with 7 bare setae and 1 aes (fused to 1 seta) (Fig.
5B
'); fourth segment partly overlapped by preceding one (Fig.
5B
'), with 1 bare seta; fifth segment with 10 bare setae, 2 of which forming an apical trithek with1 aes. Setal formula: 1-1/2-9/3-6+(1+aes)/4-1/5-8+(2+aes).
Figure 5.
Laophontodes volkerlehmanskii
sp. nov., female holotype (SMF 37216/1)
A
telson and right furcal ramus, dorsal view; Roman numbers indicate furcal setae,
B
A1,
B
' Posterior margin of fourth antennular segment, showing projection that bears the acrothek. Scale bar: 50
µm
.
A2 (Fig.
6A
). Allobasis without abexopodal seta. Exopod represented by minute bare seta. Endopod with 2 rows of inner spinules - 1 subapical and 1 proximal -; additionally, with 2 bare spines and 1 fine bare seta accompanied by 4 anterior spinules; apically with 5 setae, of which 3 geniculated and 1 biplumose.
Figure 6.
Laophontodes volkerlehmanskii
sp. nov., female paratype 2 (SMF 37218/1-15)
A
A2
B
Md
C
Mxl gnathobase
C
' Mxl coxa and basis
D
Mx
D
' Mx, proximal endite; arrow pointing to cleft tip
E
Mxp
E
' Mxp (counterpart), showing minute accompanying seta. Scale bar: 50
µm
.
Md (Fig.
6B
) with slender gnathobase bearing 4 teeth; palp 1-segmented, with 5 setae (1 missing, and 1 damaged in Fig.
6B
), of which 1 biplumose and 1 unipinnate.
Mxl (Fig.
6C, C
'). Praecoxal arthrite (Fig.
6C
) with 1 row of spinules basally, 8 bare apical spines and 1 subapical biplumose seta, additionally with 2 surface setae; coxa (Fig.
6C
') with 2 bipinnate apical setae; basis, endopod and exopod fused to single lobe (Fig.
6C
') carrying 2 unipinnate and 1 bare apical seta, 1 bare subapical seta, 3 bare and 1 bipinnate seta and few outer spinules.
Mx (Fig.
6D, D
'). Syncoxa bearing 3 rows of spinules and 2 endites. Proximal endite with 2 plumose setae and 1 bare seta with cleft tip (arrow in Fig.
6D
'), distal endite with 1 plumose and 2 bare setae. Allobasis distinct, terminally with strong claw accompanied by 1 plumose and 1 fine, bare seta. Endopod 1-segmented, knob-like, with 2 bare setae.
Mxp (Fig.
6E, E
') prehensile; syncoxa bearing 1 bare seta and single row of spinules apically (Fig.
6E
); basis with 1 row of spinules on inner and outer margins; endopod drawn out into strong claw basally accompanied by minute, bare seta (Fig.
6E
').
P1 (Figs
3B
,
7A
) with slender and bow-like intercoxal sclerite, and large, triangular praecoxa (Fig.
3B
); coxa and basis with slight longitudinal elongation, outer margin of basis forming pedestal for exopod, with 1 biplumose outer seta carrying STE, and 1 minute anterior inner seta. Endopod 2-segmented, enp-1 strong and elongate, with 2 rows of spinules on inner margin; enp-2 small, approximately 1/3 the length of enp-1, apically with 1 strong claw, 1 long, slender, geniculated seta, and 1 minute seta. Exopod 3-segmented, less than half the length of endopod, each segment with outer spinules, exp-1 carrying 1 biplumose outer seta with STE; 2 with 1 bare geniculated outer seta; exp-3 apically with 4 bare, geniculated setae.
Figure 7.
Laophontodes volkerlehmanskii
sp. nov., female paratype 2 (SMF 37218/1-15)
A
P1
B
P5 and GF with minute P6. Scale bar: 50
µm
.
P2-P4 (Fig.
8A-C
) with transversely elongated bases with outer margin bearing 1 long seta, the latter bipinnate in P2, bare in P3 and P4; exopods 3-segmented, endopods 2-segmented. All exopodal segments with outer row of robust spinules, and fine inner spinules. Exp-1 and exp-2 with 1 bipinnate outer spine; exp-3 with 3 pinnate outer spines, apically with 1 spine, whose inner margin plumose and outer margin pinnate, and 1 slender biplumose seta. Endopods narrow, enp-1 small, without spinules or setae; enp-2 elongate, of P2 and P4 with spinules, P2-P4 with 2 apical setae, both biplumose in P3 and P4, inner apical seta bare in P2. See Table
2
for setal formula.
Figure 8.
Laophontodes volkerlehmanskii
sp. nov., female paratype 2 (SMF 37218/1-15)
A
P2
B
P3
C
P4 endopod. Scale bar: 50
µm
.
P5 (Fig.
7B
) with short setophore on slender baseoendopod carrying 1 long bare seta and a few spinules; endopodal lobe reduced, represented by 2 bipinnate setae. Exopod fused to baseoendopod, slender, with 1 bare outer seta, 1 bare seta displaced to anterior surface, and 3 plumose setae - 1 subapical and 2 apical.
GF (Fig.
7B
) with single gonopore. P6 strongly reduced, limbs fused into single small plate, with pair of minute bipinnate spines.
Male
: The male differs from the female in the following characters: habitus, A1, P3 and P4 endopod, and P5.
Habitus (Figs
2B
,
9
) as in female, but slightly longer, body length (from R to FR) (median value) = 402
µm
(378-426
µm
;
N
= 2); cphth with more dorsal sensilla than female; with antero-lateral sensilla arising from socles.
Figure 9.
Laophontodes volkerlehmanskii
sp. nov. Confocal laser scanning microscopy images of male paratype 4 (SMF 37220/1)
A
habitus, dorsal view
B
habitus, ventral view. Scale bar: 25
µm
.
A1 (Figs
4B, C
,
10A, A
') 6-segmented, chirocer; first segment with 1 bipinnate seta and 3 rows of spinules; second segment with 9 bare setae (one seta missing in Fig.
10A
), and a row of short spinules; third segment with 6 bare setae (one seta missing in Fig.
10A
), and single row of spinules, segment partially overlapping fourth and fifth segment; fourth segment (Fig.
4C
, * in Fig.
10A
) minute, almost completely covered by fifth segment, with 1 bare seta; fifth segment (Fig.
10A
') swollen, with 9 setae (1 biplumose, 8 bare), 2 of which form an acrothek with 1 aes, cuticle thorn-like at upper margin; sixth segment with 10 bare setae (1 seta missing in Fig.
10A
'), 2 of which form an acrothek with 1 small aes. Setal formula: 1-1/2-8/3-6/4-1/5-7+(2+aes)/6-8+(2+aes).
Figure 10.
Laophontodes volkerlehmanskii
sp. nov., male paratype 3 (SMF 37219/1-2)
A
A1
A
' fifth and sixth antennular segment
B
P3 endopod
C
P4 endopod
D
P5. Scale bar: 50
µm
.
P3 exopod as in female, endopod (Fig.
10B
) 3-segmented; enp-1 minute and unarmed; enp-2 longest, with rows of spinules on inner and outer margins, lacking setae but inner apical margin with curved apophysis reaching to 2/3 the length of enp-3; enp-3 about 2/3 the length of enp-2, with 2 biplumose apical setae.
P4 exopod as in female, endopod (Fig.
10C
) 2-segmented; enp-2 with 1 additional flexible outer spine accompanied by few spinules at its base; apically with 2 biplumose setae. The setal formula for P3 and P4 is given in Table
2
.
Table 2.
Laophontodes volkerlehmanskii
sp. nov., setation of P2-P4. Roman numerals indicate outer spines.
| - |
Exp-1 |
Exp-2 |
Exp-3 |
Enp-1 |
Enp-2 |
Enp-3 |
| P2 |
I-0 |
I-0 |
III-2-0 |
0 |
0-2-0 |
- |
| P3 female |
I-0 |
I-0 |
III-2-0 |
0 |
0-2-0 |
- |
| P3 male |
I-0 |
I-0 |
III-2-0 |
0 |
0 (apophysis) |
0-2-0 |
| P4 female |
I-0 |
I-0 |
III-2-0 |
0 |
0-2-0 |
- |
| P4 male |
I-0 |
I-0 |
III-2-0 |
0 |
I-2-0 |
- |
P5 (Fig.
10D
) baseoendopod longer than broad, with 1 outer seta arising from short setophore; endopodal lobe incorporated into basal part of baseoendopod and represented by 1 long seta with bipinnate distal half; exopod not fused to baseoendopod, with 1 outer unipinnate seta, and 2 bipinnate setae - 1 subapical and bearing STE, and 1 apical.
Etymology.
The epithet
volkerlehmanskii
is given in dedication to the 60th birthday of LMA
Lehmanski's
father Volker Lehmanski (Gelsenkirchen, Germany).
Figure 11.
Cladogram summarizing the results of the phylogenetic analysis provided in the present contribution. Numbers in rectangles pointing to discussed characters listed in Table
3
. Underlined numbers refer to convergent deviations. Detailed explanations are given in the text.