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The most comprehensive description of variations of morphometric and meristic characters and coloration of rare deepwater pale ray Bathyraja pallida (Forster, 1967) from the North Atlantic based on all available materials is given. For the first time morphometrics are presented as percent of disc width that might be used in taxonomic studies of specimens with damaged snout and tail. Relationships between total length and disc width and the rest morphometrics have linear character except for clasper length and snout angle. Comparison of external morphological characters of juveniles and adults revealed some notable differences between them. There were almost no considerable distinctions in external morphological characters between skates from the northeastern Atlantic and Mid-Atlantic ridge. It is shown that coloration of pale ray has changed during life span. Juveniles overall have darker coloration as compared to adults. At the same time, both juveniles and mature skates keep common species-specific features of coloration of dorsal and ventral surfaces.
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ISSN 00329452, Journal of Ichthyology, 2013, Vol. 53, No. 7, pp. 465–477. © Pleiades Publishing, Ltd., 2013.
Published in Russian in Voprosy Ikhtiologii, 2013, Vol. 53, No. 4, pp. 389–404.
465
1
INTRODUCTION
The fauna of deepwater skates of the North Atlan
tic is studied insufficiently. Many species were
described rather recently (in the second half of past
century) and are known by several records only (Orlov
et al., 2006). Among them is a pale ray
Bathyraja pal
lida
that was described by Forster (1967a) in late 1960's
by two specimens caught in the Bay of Biscay. This
species is believed to be an endemic of the northeast
ern Atlantic (Valsecchi et al., 2004) and is currently
known from waters of the northern Ireland, Rockall
Trough, northern part of the Bay of Biscay, Rejkyanes
Ridge and northern part of the MidAtlantic Ridge
(MAR) by less than 15 specimens (Forster, 1967a,
1968; Gordon, Duncan, 1987, 1989; Clarke, 2000;
Hareide, Games, 2001; Orlov et al., 2006; Fossen
et al., 2008). According to IUCN Red List data pale
ray belongs to “Data Deficient” category (Orlov,
2007), i.e. there are too little data to assess its conser
vation status (range, abundance, biology, etc.). Data
on external morphology based on studies of three pale
rays (holotype, paratype, and specimen from MAR)
are published by Forster (1967a) and Orlov with coau
thors (2006). Latter publication also compiles infor
mation on distribution, capture depths and sizes of
species under consideration. Differences in morpho
1
The article is published in the original.
metric and meristic characters of nine male and
female pale rays are generally presented in the paper of
Orlov et al. (2010). Changes of the external morphol
ogy and coloration of this species with size increasing
were never previously analyzed. Meanwhile, such an
analysis allows to reveal intraspecies variability of
external morphology during ontogenesis that is very
important in taxonomic studies and also in prepara
tion of identification keys and guides since available
taxonomic information on pale ray is very limited
(Forster, 1967a; Stehmann,
B
ü
rkel, 1984
; Orlov et al.,
2006). Besides, since latest publication dealt with
studies of external morphology of pale ray (Orlov
et al., 2006) authors have got additional materials
obtained mostly during international scientific project
MARECO (www.mareco.no) that allows us to widen
knowledge of available data on external morphology
and coloration of pale ray.
MATERIALS AND METHODS
The analysis of external morphological characters
of pale ray presented here is based on examination
(depending on condition of specimens) of 30–43
morphometrics and 2–5 meristics (Table 1). All mea
surements and counts were made according to con
ventional methods (Bigelow, Schroeder, 1953; Hubbs,
Ishiyama, 1968) in agreement with schemes that are
New Data on Rare Deepwater North Atlantic Skate
Bathyraja pallida
(Forster, 1967)
(Arhynchobatidae, Rajiformes)
1
A. M. Orlov
a
and C. F. Cotton
b
a
Russian Federal Research Institute of Fisheries and Oceanography, Moscow Russia
b
Virginia Institute of Marine Science, Gloucester Point, Virginia, USA
email: orlov@vniro.ru
Abstract
—The most comprehensive description of variations of morphometric and meristic characters and
coloration of rare deepwater pale ray
Bathyraja pallida
(Forster, 1967) from the North Atlantic based on all
available materials is given. For the first time morphometrics are presented as percent of disc width that might
be used in taxonomic studies of specimens with damaged snout and tail. Relationships between total length
and disc width and the rest morphometrics have linear character except for clasper length and snout angle.
Comparison of external morphological characters of juveniles and adults revealed some notable differences
between them. There were almost no considerable distinctions in external morphological characters between
skates from the northeastern Atlantic and MidAtlantic ridge. It is shown that coloration of pale ray has
changed during life span. Juveniles overall have darker coloration as compared to adults. At the same time,
both juveniles and mature skates keep common speciesspecific features of coloration of dorsal and ventral
surfaces.
DOI:
10.1134/S0032945213040048
Keywords:
pale ray,
Bathyraja pallida
, external morphology, coloration, the North Atlantic
466
JOURNAL OF ICHTHYOLOGY
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2013
ORLOV, COTTON
Table 1.
Morphometric (in %
TL
) and meristic characters of pale ray
Bathyraja pallida
(
TL
total length; A
tip of tail
lacks; B
snout damaged and tail lacks; C
snout damaged; D
according to Forster (1967a); E
rear part of tail lacks;
Min.
minimum; Max.
maximum; Mean
mean value of character;
N
number of characters examined in all speci
mens; na
not available; characters varied in wider range as compared to published data according to Forster, 1967 and
Orlov et al., 2006 are in bold)
Chara
cter
Material examined
Min. Max. Mean
n
III
A
III IV
B
V
C
VI VII
C
VIII IX
D
X
E
XI
D
TL
,
mm 311 358 636 1285 1440 1455 1462 1490 1492 1543 1565 311 1565 1185 11
Morphometrics, %
TL
1 63.3 63.7 60.5 65.8 65.3 64.4 64.0 70.5 67.1 65.5 64.9
60.5
70.5 65.0 11
2 55.9 56.4 55.8 52.3 56.9 54.2 58.8 57.1 58.4 68.0 53.8
52.3 68.0
57.1 11
3 17.817.719.2 – 14.816.814.018.616.216.714.0
19.2
16.9 9
4 17.5 17.4 19.2 13.2 19.1 17.4 15.2 14.6
13.2 19.2
16.7 8
5 14.7 14.8 15.7 12.1 12.3 11.7
11.7 15.7
13.6 6
6 4.3 4.7 3.9 5.1 4.4 4.1 4.7 1.8 4.7 3.9 2.3 1.8
5.1
4.0 11
7 6.0 5.3 4.2 7.3 5.6 4.7 5.9 4.8 5.8 5.2 5.2
4.2 7.3
5.5 11
8 2.7 2.7 2.4 3.0 2.6 2.6 2.7 3.4 2.9 –
2.4
3.4 2.8 9
9 8.1 8.0 6.6 12.5 8.8 7.5 8.9 7.1 9.2 8.4 8.0
6.6 12.5
8.5 11
10 5.5 6.1 4.9 7.1 6.0 5.5 5.7 4.3 – 4.5 – 4.3
7.1
5.5 9
11 2.1 1.8 2.0 – 1.5 1.7 1.6 2.2 1.7 – 1.7
1.5
2.2 1.8 9
12 3.9 4.3 3.5 3.4 3.4 3.1 3.8 2.8 – 3.3 2.8
4.3
3.5 9
13 2.2 2.0 2.4 1.8 2.0 1.8 2.2 1.6 – 2.1 1.6
2.4
2.0 9
14 4.6 3.4 3.8 3.3 3.2 2.9 3.6 2.8 – 3.4 2.8
4.6
3.4 9
15 2.1 2.4 2.2 – 1.0 1.9 0.7 0.9 0.7 – 1.5
0.7 2.4
1.5 9
16 3.9 – 2.2 – 2.4 1.0 1.5 1.2 –
1.0 3.9
2.0 6
17 3.9 – 2.7 – 2.4 1.0 1.5 2.2 1.7 – 2.2
1.0 3.9
2.2 8
18 2.2 2.4 1.9 2.6 2.5 2.4 2.5 2.3 2.1 –
1.9 2.6
2.3 9
19 2.7 3.3 1.6 3.4 3.6 3.3 2.6 2.8 2.9 –
1.6 3.6
2.9 9
20 1.2 0.9 1.1 – 1.1 1.0 1.1 1.1 –
0.9 1.2
1.1 7
21 1.0 0.9 0.9 1.5 1.3 1.5 1.7 –
0.9
1.7 1.3 7
22 41.5 – 34.6 – 37.8 36.6 31.1 25.2 – 25.2
41.5
34.5 6
23 29.7 30.3 30.7 27.3 29.5 28.2 31.1 28.8 29.2
27.3 31.1
29.4 9
24 7.4 7.5 9.3 10.9 9.4 9.5 9.7 9.5 8.8 10.4 10.9
7.4
10.9 9.4 11
25 8.6 8.7 8.3 10.8 9.2 8.2 10.1 10.5 10.7 9.1 8.6
8.2 10.8
9.3 11
26 4.5 4.2 3.8 3.5 3.5 3.5 3.0 4.7 3.6
3.0
4.7 3.8 9
27 9.3 9.4 – 11.3 10.8 9.2 10.2 – 9.4 –
9.2 11.3
9.9 7
28 2.5 2.1 0.8 1.9 1.9 1.8 2.3 1.9 – 1.3 –
0.8 2.5
1.8 9
29–– 1.6––––5.86.85.8
6.8
6.3 3
30 1.4 1.5 1.3 1.7 1.6 1.4 1.7 1.9 1.7 1.5 1.6
1.3
1.9 1.6 11
31 1.6 1.5 1.4 1.8 1.9 1.7 2.1 2.5 1.9 1.7 1.8
1.4
2.5 1.8 11
32 1.2 1.3 0.9 1.3 1.3 1.3 1.6 1.6 1.5 1.3 1.3
0.9
1.6 1.3 11
33 15.6 15.3 14.2 19.1 16.7 15.7 17.4 12.6 18.9 17.8 17.3 12.6
19.1
16.4 11
34 11.0 11.1 11.3 14.6 11.5 10.6 12.7 8.7 13.1 11.3 12.2 8.7
14.6
11.7 11
35 14.1 15.4 11.5 6.8 10.3 9.9 11.4 11.9 9.1
6.8 15.4
11.1 9
36 14.9 16.5 14.5 13.5 17.1 15.6 17.4 18.1 15.6
13.5
18.1 15.9 9
37 7.9 7.9 8.3 – 26.0 27.6 – 26.3 – 25.9
7.9 27.6
18.6 9
38 48.6 49.9 53.1 54.6 54.2 49.8 57.8 57.4 60.0 55.7 56.9
48.6
60.0 54.4 7
39 35.5 36.4 37.1 33.9 34.4 37.5 36.9 31.8 35.0 31.8
37.5
35.4 9
JOURNAL OF ICHTHYOLOGY
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NEW DATA ON RARE DEEPWATER NORTH ATLANTIC SKATE 467
used in recent years (Stehmann, Merrett, 2001; Orlov
et al., 2006; Stehmann et al., 2008).
The material analyzed is represented by 12 speci
mens of pale ray that was examined by authors during
2005–2010 in various museums: ZMUB 19465, VIMS
11577, VIMS 11758, NMSZ 2000.130.462, NMSZ
2000.130.80, NHM 1967.2.13.1, NHM 1967.2.13.2,
NHM 1985.11.14.1, NHM 1985.11.14.2, NHM
1985.11.14.3, NHM 1985.11.14.4, NMI 13.1998
(ZMUB—Zoological Museum, Bergen University,
Bergen, Norway; VIMS—Virginia Institute of Marine
Science, Gloucester Point, Virginia, USA; NMSZ—
National Museum of Scotland, Edinburgh, Scotland;
NHM (formerly BMNH)—British Museum of Natu
ral History, London, Great Britain; NMI—National
Museum of Ireland, Dublin, Ireland). Specimen from
NMI with total length (
TL
) 162 cm (NMI 13.1998)
caught by Clarke (2000) was completely not accept
able for measurements of morphometrics due to huge
deformation and damage of frontal part of the head
(Fig. 1a). There was a lack of the part of tail in some
specimens or they had damaged snout that made not
possible examination of respective characters. In that
cases
TL
was calculated by disc width (
dw
) using the
formula that was estimated on the base of not damaged
specimens:
TL
= 1.473
dw
+ 39.599 (
R
2
= 0.993,
n
=
9)
. During short visit of the senior author to NHM he
was provided with the opportunity to examine four
specimens from the Bay of Biscay only (Forster, 1968)
that were in far from ideal condition (Fig. 1b). Exam
ination of holotype and paratype (NHM 1967.2.13.1
and NHM 1967.2.13.2) of pale ray were technically
not possible at that time. In this connection, we had to
use in our analysis the data published by Forster
(1967a).
RESULTS AND DISCUSSION
General Characteristics of External Morphology
Data on the external morphology of pale ray was
limited until present by description of characters of
holotype, paratype and single specimen from MAR
(Forster, 1967a; Orlov et al., 2006) and also by com
parison of morphometrics and meristics of nine males
and females of the species under consideration (Orlov
et al., 2010).
Results of our study (Table 1) show that all the
morphometrics and the majority of meristics of pale
Table 1.
(Contd.)
Chara
cter
Material examined
Min. Max. Mean
n
III
A
III IV
B
V
C
VI VII
C
VIII IX
D
X
E
XI
D
40 35.0 36.9 34.3 36.2 36.4 34.5 32.6 32.7 33.2 32.6
36.9
34.6 7
41 41.5 42.7 39.3 40.6 41.4 41.0 36.9 36.9
42.7
40.5 7
42 50.2 46.1 46.4 46.3 42.5 44.3 41.0 44.4 41.0
50.2
45.1 8
Meristics
43999586––––81–––81
99
90.3 4
44 19 17 16 17 – 16 19 – 16 19 17.3 6
45111–0210–
02
0.9 7
46 30 28 25 25 24 31 25 31 29 25
24
31 27.3 10
47262624 –22243522352325223526.210
Note: Morphometrics: 1
disc width, 2
disc length, 3
preorbital snout length, 4
preoral snout length, 5
prenasal snout length,
6
horizontal diameter of orbit, 7
interorbital width, 8
spiracle length, 9
interspiracular width, 10
orbit + spiracle, 11
DI
height, 12
length of DI base, 13
DII height, 14
length of DII base, 15
distance between DI and DII, 16
length of C base,
17
postdorsal length of tail, 18
height of tail at V tips, 19
width of tail at V tips, 20
height of tail at DI origin, 21
width of tail
at DI origin, 22
lateral fold length, 23
head length, 24
mouth width, 25
internasal distance, 26
nasal curtain length,
27
nasal curtain width, 28
width of each lobe of nasal curtain, 29
distance between lobes of nasal curtain, 30
1st gill slit length,
31
3rd gill slit length, 32
5th gill slit length, 33
distance between 1st gill slits, 34
distance between 5th gill slits, 35
length of
V anterior lobe, 36
length of V posterior lobe, 37
preanal length of clasper, 38
distance between snout tip and center of anus,
39
distance between snout tip and maximum disc width, 40
distance between center of anus and DI origin, 41
distance between
center of anus and DII origin, 42
distance between center of anus and tip of tail. Meristics: 43
snout angle, 44
number of median
thorns, 45
number of thorns between DI and DII, 46
number of tooth rows on upper jaw, 47
number of tooth rows on lower jaw.
Material examined: I
NMCZ 2000.130.80, II
NMCZ 2000.130.462, III
VIMS 11577, IV
NHM 1985.11.14.4, V
NHM
1985.11.14.3, VI
NHM 1985.11.14.2, VII
NHM 1985.11.14.1, VIII
ZMUB 19465, IX
BMNH 1967.2.13.1, X
VIMS
11758, XI
NHM 1967.2.13.2.
468
JOURNAL OF ICHTHYOLOGY
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2013
ORLOV, COTTON
ray vary in considerably wider range in comparison
with previous data. Only number of median thorns in
specimens examined by us (16–19) was less than that
(16–21) in the paper of Stehmann and
B
ü
rkel
(1984).
Later data was probably based on the examination of
holotype and paratype from NHM that were not avail
able for us. The reason of variability of characters in
wider range as compared to previously known data is
larger number of specimens examined and presence
among them of juveniles. All previous taxonomic stud
ies (Forster, 1967a; Orlov et al., 2006) dealt with
mature specimens only.
The analysis of relationships between total length
and various morphological features (Table 2) show
that in the majority cases they have a linear character.
Only in regard to clasper length and snout angle this
relationship is expressed as exponential function. In
most cases relationship between total length and vari
ous characters had high value of significant approxi
mation (
R
2
> 0.8) and might be characterized as
strong. Only in three cases it was weak (
R
2
< 0.5)—in
(а)
(b)
Fig. 1.
Adult specimens of pale ray
Bathyraja pallida
: (a)
NMI 13.1998, (b) part of lot NHM 1985.11.14.
Table 2.
Relationships between total length (
TL
) and various
morphometric characters of pale ray
Bathyraja pallida
(
R
2
value of significant approximation,
a
and
b
parameters
of equation, number of characters is the same as in Table 1)
Characters Type of re la 
tionship
abR
2
1 1 0.6731 20.891 0.9935
2 1 0.5894 18.201 0.9582
3 1 0.1546 11.639 0.9465
4 1 0.1509 12.904 0.9088
5 1 0.1092 17.741 0.9875
6 1 0.0342 5.4160 0.5690
7 1 0.0548 0.0636 0.8872
8 1 0.0300 1.8373 0.9514
9 1 0.0878 2.0832 0.8369
10 1 0.0522 2.6629 0.8508
11 1 0.0168 1.1342 0.8934
12 1 0.0310 3.1021 0.9470
13 1 0.0181 1.5385 0.9240
14 1 0.0296 3.7653 0.9463
15 – weak
16 – weak
17 – weak
18 1 0.0246 –1.1185 0.9719
19 1 0.0328 –3.1397 0.9094
20 1 0.0108 0.0004 0.9886
21 1 0.0171 –3.1619 0.9607
22 1 0.3008 35.204 0.8515
23 1 0.2876 5.0488 0.9904
24 1 0.1050 –9.2030 0.9685
25 1 0.0988 –4.4457 0.9397
26 1 0.0349 2.3171 0.8776
27 1 0.1016 –1.0186 0.9672
28 1 0.0184 0.3863 0.8123
29 1 0.0980 –52.713 0.9819
30 1 0.0173 –1.5020 0.9365
31 1 0.0209 –2.4064 0.9108
32 1 0.0152 –1.7085 0.9439
33 1 0.1749 –9.2084 0.9183
34 1 0.1177 0.3396 0.8858
35 1 0.0889 –16.450 0.8340
36 1 0.1692 8.9661 0.9591
37 2 0.0005 1.8522 0.9818
38 1 0.5811 –32.321 0.9837
39 1 0.3440 7.9833 0.9818
40 1 0.3365 8.0401 0.9880
41 1 0.3939 7.0882 0.9903
42 1 0.4247 24.295 0.9835
43 2 198.2700 –0.1245 0.9354
Note: Weak relationship means that R2 < 0.5. Type of relationship:
1linear y = ax + b, 2exponential y = axb.
JOURNAL OF ICHTHYOLOGY
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NEW DATA ON RARE DEEPWATER NORTH ATLANTIC SKATE 469
Table 3.
Morphometric characters in % of disc width (dw) of pale ray
Bathyraja pallida
(all keys are given in Table 1)
Char
acter
Material examined
Min. Max. Mean
n
I II III IV V VI VII VII IX X XI
dw
,
mm 197 228 385 845 941 937 936 1050 1001 1010 1016 197 1050 776.9 11
Morphometrics, % dw
TL
157.9 157.0 165.2 152.1 153.0 155.3 156.2 141.9 149.0 152.8 154.1 141.9 165.2 154.0 11
2 88.3 88.6 92.2 79.5 87.1 84.1 91.8 81.0 87.0 104.0 82.9 79.5 104.0 87.9 11
3 28.1 27.8 31.7 22.9 26.3 19.8 27.7 24.8 25.7 19.8 31.7 26.1 9
4 27.6 27.3 31.7 20.5 27.1 25.9 23.3 22.5 20.5 31.7 25.7 8
5 23.2 23.2 26.0 – 18.8 – 17.5 – 17.8 – 17.5 26.0 21.1 6
6 6.9 7.4 6.5 7.7 6.8 6.4 7.3 2.5 7.0 5.9 3.5 2.5 7.7 6.2 11
7 9.4 8.4 7.0 11.1 8.5 7.4 9.2 6.8 8.6 7.9 8.0 6.8 11.1 8.4 11
8 4.2 4.3 3.9 4.6 4.0 4.1 4.3 4.8 – 4.5 – 3.9 4.8 4.3 9
9 12.8 12.5 10.9 19.1 13.5 11.7 13.9 10.1 13.7 12.9 12.3 10.1 19.1 13.0 11
10 8.7 9.6 8.1 10.8 9.1 8.5 8.9 6.1 6.9 6.1 10.8 8.5 9
11 3.2 2.8 3.4 2.3 2.7 2.6 3.2 2.5 – 2.6 2.3 3.4 2.8 9
12 6.2 6.7 5.7 5.3 5.3 4.9 5.4 4.2 5.1 4.2 6.7 5.4 9
13 3.4 3.2 3.9 – 2.7 3.1 2.7 3.1 2.4 – 3.2 2.4 3.9 3.1 9
14 7.3 5.3 6.2 – 5.0 5.0 4.6 5.1 4.2 – 5.2 4.2 7.3 5.3 9
15 3.2 3.7 3.6 – 1.6 3.0 1.1 1.3 1.0 – 2.3 1.0 3.7 2.3 9
16 6.2 – 3.6 3.7 1.6 2.3 1.8 – – – 1.6 6.2 3.2 6
17 6.2 – 4.4 – 3.7 1.6 2.3 3.1 2.5 – 3.4 1.6 6.2 3.4 8
18 3.5 3.8 3.1 3.9 3.9 3.8 3.9 3.3 – 3.3 – 3.1 3.9 3.6 9
19 4.3 5.1 2.6 5.2 5.5 5.1 4.1 4.0 – 4.5 2.6 5.5 4.5 9
20 1.9 1.5 1.8 1.6 1.6 1.7 1.6 1.5 1.9 1.7 7
21 1.6 1.4 1.6 2.3 2.0 2.4 2.4 – 1.4 2.4 2.0 7
22 65.5 57.1 57.8 56.8 48.6 35.7 35.7 65.5 53.6 6
23 47.0 47.6 50.6 41.5 45.2 43.8 48.6 40.9 44.6 40.9 50.6 45.5 9
24 11.7 11.8 15.3 16.6 14.3 14.7 15.2 13.5 13.1 15.8 16.8 11.7 16.8 14.5 11
25 13.5 13.6 13.8 16.4 14.0 12.8 15.7 15.0 15.9 13.9 13.3 12.8 16.4 14.3 11
26 7.2 6.5 6.2 5.4 5.3 5.4 4.7 6.7 – 5.4 4.7 7.2 5.9 9
27 14.7 14.8 17.2 16.5 14.3 15.9 14.4 14.3 17.2 15.4 7
28 4.0 3.3 1.3 2.9 2.9 2.8 3.6 2.7 – 2.0 – 1.3 4.0 2.8 9
29–– 2.6––––8.210.4– 2.610.47.13
30 2.1 2.3 2.1 2.6 2.4 2.1 2.7 2.8 2.5 2.3 2.5 2.1 2.8 2.4 11
31 2.5 2.4 2.3 2.8 2.8 2.7 3.2 3.5 2.8 2.7 2.8 2.3 3.5 2.8 11
32 1.8 2.0 1.6 2.0 2.0 2.1 2.5 2.3 2.2 2.0 2.0 1.6 2.5 2.0 11
33 24.7 24.1 23.4 29.1 25.6 24.3 27.1 17.9 28.2 27.2 26.7 17.9 29.1 25.3 11
34 17.4 17.5 18.7 22.1 17.6 16.4 19.9 12.4 19.5 17.3 18.8 12.4 22.1 18.0 11
35 22.3 24.2 19.0 10.3 15.7 15.4 17.8 16.9 13.9 10.3 24.2 17.3 9
36 23.5 25.9 23.9 20.6 26.1 24.2 27.2 25.6 23.8 20.6 27.2 24.5 9
37 12.4 12.5 13.8 – 39.7 42.9 – 37.3 – 39.6 – 12.4 42.9 28.3 9
38 76.7 78.3 87.8 83.1 82.9 77.4 90.3 81.4 89.4 85.1 87.7 76.7 90.3 83.6 7
39 56.0 57.1 61.3 51.5 52.6 58.2 57.6 45.1 53.5 45.1 61.3 54.8 9
40 55.3 57.9 56.6 55.4 56.5 54.0 46.3 48.7 51.2 46.3 57.9 53.5 7
41 65.5 67.1 64.9 62.1 64.2 64.0 52.4 52.4 67.1 62.9 7
42 79.2 – 76.1 – 71.0 71.9 66.3 62.9 61.1 – 68.4 61.1 79.2 69.6 8
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Fig. 2.
Mature males of pale ray
Bathyraja pallida
: (a) and (b) ZMUB 19465, (c) and (d) VIMS 11758, (a) and (c) dorsal surface,
(b) and (d) ventral surface.
(а) (b)
(d)(c)
Fig. 3.
Juvenile males of pale ray
Bathyraja pallida
: (a) and (b) NMCZ 2000.130.80; (c) and (d) NMCZ 2000.130.462; (a) and
(c) dorsal surface; (b) and (d) ventral surface.
regard to distance between dorsal fins, length of caudal
fin base and postdorsal length of tail that might be
associated with several reasons. All the three charac
ters are measured by rather small values relative to
total length (0–3.9%). Thus even insignificant inaccu
racy in measurements might lead to such results. On
the other hand, these characters might have notable
variability. For instance, postdorsal length of tail varies
(а) (b)
(d)(c)
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NEW DATA ON RARE DEEPWATER NORTH ATLANTIC SKATE 471
considerably since tail behind the caudal fin lacks in
some specimens. Such variability of this character also
occurs in other deepwater skate Bigelow’s ray
Rajella
bigelowi
(Stehmann, 1978, 1995; Orlov et al., 2006).
Judging by the variability of the number of middorsal
thorns (0–2) the distance between dorsal fins in pale
ray is also rather variable character that is peculiar to
some other deepwater North Atlantic skates too
(Orlov et al., 2006). Relationship between total length
and orbit diameter was medium (
R
2
= 0.569) that is
probably associated with the measurements of orbit by
us versus eye diameter in previous publications (For
ster, 1967a; Orlov et al., 2006).
The analysis of published sources (Tempelman,
1965; Forster, 1967b) and our own data (Table 1,
Figs. 1a, 2) show that large deepwater skates caught
mostly by bottom longlines are getting often to hands
of researchers with damaged snout and sometimes
with lack of part of tail. In such events measurements
of total length is not possible and the best solution of
this situation is using of disc width (Table 3). Until
present description of morphometrics of pale ray as
percents of disc width was not available. The analysis
of relationships between disc width and various charac
ters (Table 4) shows the same picture as in regard to
total length (see Table 2). Weakest relationships were
observed in relation to distance between dorsal fins,
Fig. 4.
Juvenile male of pale ray
Bathyraja pallida
VIMS
11577: (a) dorsal surface, (b) ventral surface.
Table 4.
Relationships between disc width (dw) and various
morphometric characters of pale ray
Bathyraja pallida
(all
explanations are given in Table 2)
Character Ty p e
of relationship
abR
2
21 0.8703 4.2905 0.9525
3 1 0.2260 18.973 0.9256
4 1 0.2254 15.719 0.9395
5 1 0.1587 22.458 0.9801
6 1 0.0487 8.0763 0.5271
7 1 0.0807 2.1949 0.8773
8 1 0.0450 1.2122 0.9775
9 1 0.1290 1.7886 0.8233
10 1 0.0758 5.5130 0.8207
11 1 0.0253 1.4064 0.9257
12 1 0.0460 4.0366 0.9568
13 1 0.0267 2.1572 0.9267
14 1 0.0439 4.7094 0.9531
15 weak
16 weak
17 0.0196 8.2395 0.5108
18 1 0.0363 –0.1022 0.9614
19 1 0.0485 –1.8926 0.9051
20 1 0.0160 0.3825 0.9924
21 1 0.0255 –2.6945 0.9801
22 1 0.4242 61.523 0.7921
23 1 0.4231 17.079 0.9787
24 1 0.1543 –4.6319 0.9538
25 1 0.1476 –2.0381 0.9568
26 1 0.0530 2.6096 0.9224
27 1 0.1556 –0.3211 0.9704
28 1 0.0273 0.2480 0.8138
29 1 0.1311 –39.717 0.9433
30 1 0.2060 –1.1587 0.9610
31 1 0.0315 –2.0817 0.9416
32 1 0.0227 –1.3143 0.9585
33 1 0.2550 –0.0498 0.8904
34 1 0.1712 6.0909 0.8555
35 1 0.1326 18.828 0.8476
36 1 0.2513 –3.6360 0.9662
37 2 0.0017 1.7901 0.9874
38 1 0.8610 –12.533 0.9849
39 1 0.5022 25.075 0.9560
40 1 0.4929 23.267 0.9712
41 1 0.5743 26.105 0.9680
42 1 0.6184 47.727 0.9702
43 2 177.47 –0.1150 0.9046
(а)
(b)
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length of caudal fin base, postdorsal length of tail, and
horizontal diameter of orbit.
Recently schemes of measurements of skates are
notably modified that is accompanied by using of
some additional characters (Last et al., 2008, 2010). In
our opinion, this approach is correct in case of
description of new species with small linear sizes and
when specimens examined are in good condition.
Besides, use of additional morphological characters
complicates comparison of newly obtained data with
previously published information. In our case, mea
surement of some morphometrics in adult pale rays
with the total length over 130 cm, often hardly
deformed during long storing in cramped tanks,
becomes not only very difficult but also makes no
sense.
Ontogenetic and Geographical Variability
of External Morphological Characters
Changes of morphometrics and meristics of pale
ray with growth were not analyzed until present.
Meanwhile, results of such analysis (Table 5) allow to
reveal their variability with changes of linear sizes that
is important in elaboration of speciesspecific diag
nostic characters.
As our studies show, juvenile and adults pale rays
differ one from another by the number characters. In
the whole, increasing of body length is accompanied
by increasing of disc width that results in larger values
of associated characters in adults as compared to juve
niles: interorbital width, interspiracular width, mouth
width, internasal width, nasal curtain width, gill slit
lengths, spaces between gill slits. Besides, adults have
wider tail. Juveniles have shorter disc with longer and
blunter snout and longer nasal curtain. Besides, they
have longer tail with longer lateral fold, longer dis
Table 5.
Differences of morphometric and meristic char
acters of juvenile and adult pale rays
Bathyraja pallida
(Min., Max. and Mean
minimum, maximum and mean
value of character respectively; number of specimens ex
amined is given in brackets, number of characters as in Ta
ble 1)
Charac
ter
Juveniles (3) Adults (8)
Min Max Mean Min Max Mean
TL
, mm 311 636 435 1285 1565 1467
Morphometrics,
% TL
1 60.5 63.7 62.5 64.0 70.5 65.9
2 55.8 56.4 56.1 52.3 68.0 57.4
3 17.7 19.2 18.2 14.0 18.6 16.2
4 17.4 19.2 18.0 13.2 19.1 15.9
5 14.7 15.7 15.1 11.7 12.3 12.0
6 3.9 4.7 4.3 1.8 5.1 3.9
7 4.2 6.0 5.2 4.7 7.3 5.6
8 2.4 2.7 2.6 2.6 3.4 2.9
9 6.6 8.1 7.6 7.1 12.5 8.8
10 4.9 6.1 5.5 4.3 7.1 5.5
11 1.8 2.1 2.0 1.5 2.2 1.8
12 3.5 4.3 3.9 2.8 3.8 3.3
13 2.0 2.4 2.2 1.6 2.2 1.9
14 3.4 4.6 3.9 2.8 3.6 3.2
15 2.1 2.4 2.2 0.7 1.9 1.1
16 2.2 3.9 3.1 1.0 2.4 1.5
17 2.7 3.9 3.3 1.0 2.4 1.8
18 1.9 2.4 2.2 2.1 2.6 2.4
19 1.6 3.3 2.5 2.6 3.6 3.1
20 0.9 1.2 1.1 1.0 1.1 1.1
21 0.9 1.0 1.0 1.3 1.7 1.5
22 34.6 41.5 38.0 25.2 37.8 32.7
23 29.7 30.7 30.2 27.3 31.1 29.0
24 7.4 9.3 8.1 8.8 10.9 9.9
25 8.3 8.7 8.5 8.2 10.8 9.6
26 3.8 4.5 4.2 3.0 4.7 3.6
27 9.3 9.4 9.4 9.2 11.3 10.2
28 0.8 2.5 1.8 1.3 2.3 1.8
29 1.6 1.6 1.6 5.8 6.8 6.3
30 1.3 1.5 1.4 1.4 1.9 1.6
31 1.4 1.6 1.5 1.7 2.5 1.9
32 0.9 1.3 1.1 1.3 1.6 1.4
33 14.2 15.6 15.0 12.6 19.1 16.9
34 11.0 11.3 11.1 8.7 14.6 11.8
35 11.5 15.4 13.7 6.8 11.9 9.9
36 14.5 16.5 15.3 13.5 18.1 16.2
37 7.9 8.3 8.0 25.9 27.6 26.5
Table 5.
(Contd.)
Char
acter
Juveniles (3) Adults (8)
Min Max Mean Min Max Mean
38 48.6 53.1 50.5 49.8 60.0 55.8
39 35.5 37.1 36.3 31.8 37.5 34.9
40 34.3 36.9 35.4 32.6 36.4 34.3
41 39.3 42.7 41.2 36.9 41.4 40.0
42 46.1 50.2 48.1 41.0 46.4 44.1
Meristics
43 86 99 93.3 81 81 81.0
44 16 19 17.3 16 19 17.3
45 1 1 1.0 0 2 0.8
46 25 30 27.7 24 31 27.1
47 24 26 25.3 22 35 26.6
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tance between dorsal fins, and longer caudal fin as
compared to adults.
Differences between type specimens from the
northeastern Atlantic and specimen from the Mid
Atlantic ridge (Orlov et al., 2006) allowed to hypothe
size that these differences are result of geographic iso
lation of specimens inhabited midAtlantic and Euro
pean continental slope. We decided to check this sug
gestion with the use of larger number of specimens
(8 from the northeastern Atlantic and 3 from the Mid
Atlantic ridge). Though the length of specimens in sam
ples compared was considerably different (Table 6), their
mean length was quite comparable (1171 and 1123 mm
respectively). The analysis did not reveal any principal
differences between specimens from both areas except
for larger disc length and slightly lesser values of inter
orbital distance, interspiracular width, tail width at
V
tips, length of lateral fold, space between gill slits,
length of
V
anterior lobe, and distance between anus
and
D
2
in MidAtlantic ridge specimens. Partly these
differences are probably related to larger number of
juveniles in the sample from the northeastern Atlantic.
The same reason is possibly responsible for blunter
Fig. 5.
Female pale ray
Bathyraja pallida
with
TL
160–162 photographed by lander “ROBIO” on 16.07.2004 at the MidAtlantic
ridge during Norwegian RV “G.O. Sars” cruise (photo courtesy Nicola Cousins, Oceanlab, University of Aberdeen, Scotland).
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ORLOV, COTTON
snout in specimens from the northeastern Atlantic.
The rest differences are probably related to intraspe
cies variability of characters.
There is notable larger number of tooth rows at the
lower jaw in skates from the northeastern Atlantic
(mean 27.6 vs. 23.0). In juveniles and adults this char
acter practically does not differ (25.3 and 26.6 respec
tively). However, maximal values (35) occurred in two
adults from the Bay of Biscay, while in the MidAtlan
tic ridge specimens it does not exceed 24. In any case,
the analysis even of currently available materials does
not allow us to conclude regarding existence of signif
icant differences in external morphology of pale rays
from the northeastern Atlantic and MidAtlantic ridge
associated with their geographical isolation.
Coloration
Till present, data on coloration of pale ray were
limited by its description in adult skates based on
examination of limited number of specimens (Forster,
1967a; Stehmann,
B
ü
rkel, 1984
). Meanwhile, our
investigations show that coloration of this species is
object of notable ontogenetic variability. Besides, pres
ervation also changes coloration of pale ray specimens
(Forster, 1967a).
As available materials allow judging (Table 7,
Figs. 2–4), coloration of dorsal surface both of juve
niles and adults is always unicolor, without white or
dark blotches. Exception is probably smallest speci
mens which anterior lobes of pelvic fins are partly
white. White patches also occurred on the external
part of claspers in smallest and largest males. However,
the main difference of coloration of the dorsal surface
between juveniles and adults is that young skates are
colored darker. Two juvenile males with total length 31
Table 6.
Comparison of morphometric and meristic char
acters of pale ray
Bathyraja pallida
from the northeast At
lantic (NEA) and MidAtlantic ridge (MAR) (explanations
are given in Table 5, na
not available)
Character
Region (number of specimens)
СВА (8) САХ (3)
Min. Max. Mean Min. Max. Mean
TL
, mm 311 1565 1171 636 1543 1223
Morphometrics, %
TL
1 63.3 67.1 64.8 60.5 70.5 65.5
2 52.3 58.8 55.8 55.8 68.0 60.3
3 14.8 18.6 17.1 14.0 19.2 16.4
4 13.2 17.5 16.0 15.2 19.2 17.8
5 12.1 14.8 13.9 11.7 15.7 13.2
6 2.3 5.1 4.3 1.8 3.9 3.2
7 4.7 7.3 5.7 4.2 5.2 4.7
8 2.6 3.0 2.7 2.4 3.4 2.9
9 7.5 12.5 8.9 6.6 8.4 7.4
10 5.5 7.1 6.0 4.3 4.9 4.6
11 1.5 2.1 1.7 2.0 2.2 2.1
12 2.8 4.3 3.5 3.5 3.8 3.6
13 1.6 2.2 1.9 2.2 2.4 2.3
14 2.8 4.6 3.4 3.6 3.8 3.7
15 0.7 2.4 1.5 0.9 2.2 1.6
16 1.0 3.9 2.2 1.2 2.2 1.7
17 1.0 3.9 2.1 2.2 2.7 2.4
18 2.2 2.6 2.4 1.9 2.3 2.1
19 2.6 3.6 3.2 1.6 2.9 2.4
20 0.9 1.2 1.1 1.1 1.1 1.1
21 0.9 1.5 1.3 0.9 1.7 1.3
22 31.1 41.5 36.7 25.2 34.6 29.9
23 27.3 31.1 29.4 28.8 30.7 29.5
24 7.4 10.9 9.3 9.3 10.4 9.7
25 8.2 10.8 9.3 8.3 10.5 9.3
26 3.0 4.5 3.7 3.6 4.7 4.0
27 9.2 11.3 10.0 9.4 9.4 9.4
28 1.8 2.5 2.1 0.8 1.9 1.3
29 1.6 6.8 4.7
30 1.4 1.7 1.6 1.3 1.9 1.6
31 1.5 2.1 1.8 1.4 2.5 1.9
32 1.2 1.6 1.4 0.9 1.6 1.3
33 15.3 19.1 17.0 12.6 17.8 14.9
34 10.6 14.6 12.1 8.7 11.3 10.5
35 6.8 15.4 11.3 9.1 11.9 10.8
36 13.5 17.4 15.8 14.5 18.1 16.0
37 7.9 27.6 17.4 8.3 26.3 20.2
Table 6 .
(Contd.)
Character
Region (number of specimens)
СВА (8) САХ (3)
Min. Max. Mean Min. Max. Mean
38 48.6 60.0 54.0 53.1 57.4 55.4
39 33.9 37.5 35.7 31.8 37.1 34.6
40 32.7 36.9 35.0 32.6 34.3 33.4
41 40.6 42.7 41.4 36.9 39.3 38.1
42 41.0 50.2 45.1 44.3 46.1 45.2
Meristics
43 95 99 97.0 81 86 83.5
44 16 19 17.3 16 19 17.5
45 0 2 1.0 0 1 0.5
46 24 31 27.7 25 29 26.3
47 22 35 27.6 22 24 23.0
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Table 7.
Variations of coloration of pale ray
Bathyraja pallida
of different size (pres.
preserved, fresh
freshcaught specimens, number of specimens as in Table 1,
na
not available)
Character I (pres.) II (pres.) III (fresh) VIII (fresh) X (fresh)
TL, mm
311 358 636 1490 1543
Dorsal surface
Background coloration Light brown Light brown Dark brown Gray Grayishbrown
White areas
on V
anterior lobe +
White areas on claspers + +
Ventral surface
Background coloration Light brown Light brown Dark brown Grayishbrown Light brown
Presence of white areas:
– In center of snout + + + +
– Around nostrils and nasal curtain + + + + +
– Around mouth + + + + +
– Around gill slits + + + + +
– In center of abdomen + + + + +
– At the border of
P
and
V
anterior lobe + + + + +
– On
V
anterior lobe + + + + +
– Around anus + + + + +
– At tail origin + + + + +
– On claspers + + + + +
– On tail tip and
C
–++na
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ORLOV, COTTON
and 36 cm after preservation were colored light brown
(“coffee with milk”). Dorsal surface of freshcaught
juvenile male with
TL
64 cm has unicolor dark brown
coloration with slightly lighter area along the vertebral
column. Dorsal surface of large mature skates in fresh
condition is colored from light grey to dark grey and
grayishbrown. By this, male with
TL
149 cm had an
area of dorsal surface along the vertebral column col
ored somewhat lighter and rear part of tail colored
slightly darker as compared to the rest part of dorsal
surface. Male with damaged snout and lack of part of
tail (estimated
TL
154 cm) against the background of
uniform dark brown coloration had lighter area along
vertebral column and dark areas between spine and
wings, and also darker frontal edges of pectoral fins
and tail. Specimens from NMI and NHM that are
stored in fixative for a long currently have uniform col
oration from grey to brown. Data by Forster (1967a)
allow judging about coloration of holotype and
paratype. This author noted that fresh specimens have
white dorsal surface which after preservation became
pale brown. Underwater images (Fig. 5) testify that
coloration of dorsal surface of pale ray in water is light,
closer to white.
Coloration of ventral surface in juveniles and adults
of species under consideration has many similarities
and, in the whole, corresponds with previously pub
lished descriptions (Forster, 1967a). It is characterized
by existence of white blotches of irregular shape along
the midbody line (Stehmann, Bürkel, 1984). Forster
(1967a) noted the presence of such blotches around
mouth, nostrils, gill slits and anus, at tail origin and
anterior lobe of pelvic fins with adjacent areas of disc.
Males in addition have white tips and internal surface
of claspers. Practically all of abovementioned features
of ventral surface coloration were detected by us both
in juvenile and adult pale rays (Table 7, Figs. 2–4).
Nevertheless, during this investigation some details
were found. Thus, all specimens except for smallest
one have single or several small white spots of irregular
shape in central part of snout that was not mentioned
in previous publications (Forster, 1967a; Stehmann,
Bürkel, 1984). Mature male with
TL
149 cm had also
white caudal fin and tip of tail. Anterior lobes of pelvic
fins in juvenile male with
TL
64 cm were not com
pletely white (as in the rest specimens) but in the upper
part only. There were some variations in claspers col
oration. Smallest specimen had dark blotches at the
internal part of claspers, in another juvenile male it
was completely white. Juvenile male with
TL
64 cm
had very small claspers (notably less than posterior
lobe of pelvic fins) with white tips only. Adult male
with
TL
149 cm had tips of claspers considerably
darker than clasper itself. Inner surface of claspers in
male with
TL
154 cm wore dark blotches.
To characterize particular features of ventral sur
face coloration of pale ray better it should be noted
that white patches around nostrils, mouth, and gill slits
merge together into the whole white area. This area
looks like a horse shoe that ends at the border or
slightly extends beyond the border between the head
and abdomen. Another white patch in the central part
of abdomen is located along midbody line and does
not reach its middle point. In smallest skates this patch
has rectangular shape, in larger specimens it became
triangular (looks like arrowhead).
Forster (1967a) noted that ventral surface in fresh
caught specimens is light brown but after preservation
turns to moderately dark brown. We didn’t find princi
pal distinctions in coloration of dorsal and ventral sur
faces in smallest specimens, not those in freshcaught
juvenile male with
TL
64 cm as well. There was a dif
ferent situation in relation to mature skates. Ventral
surface of their body was considerably darker as com
pared to dorsal one that well corresponds to previously
published data (Forster, 1967a; Stehmann, Bürkel,
1984). In the whole, the main feature of ventral surface
coloration is the same as in regard to dorsal one—
juveniles are colored considerably darker as compared
to adults.
ACKNOWLEDGMENTS
This manuscript would not have been possible
without the input of our many colleagues. Matthias
Stehmann (ICHTHYS, Hamburg, Germany) helped
with the ID of some specimens. James Orr (Alaska
Fisheries Science Center, Seattle, USA) explained
some specific measurements. Ingvar Byrkjedal, (Zoo
logical Museum, University of Bergen, Bergen, Nor
way), Patrick Campbell and Roberto Miguez, (British
Museum of Natural History, London, Great Britain),
Geoff Swinney (National Museums of Scotland,
Edinburgh, Scotland), Mark Holmes (National
Museum of Ireland, Dublin, Ireland), Maurice Clarke
(Marine Research Institute, Galway, Ireland), and
Monty Priede (Oceanlab, University of Aberdeen,
Newburgh, Scotland) made the examination of
museum material possible and provided the facilities
and equipment for these analyses. Nicola Cousins
(Oceanlab, University of Aberdeen, Newburgh, Scot
land) kindly provided us with underwater images of
pale ray made by ROBIO lander. We are grateful to
these colleagues for their valuable contribution to this
study.
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... Объяснить причины обнаруженных географических различий в окраске особей ската Ричардсона пока не представляется возможным. Однако имеются сведения о специфике окраски в водах САХ и СВА и других глубоководных скатов, например, ската Йенсена Amblyraja jenseni, бледного ската Bathyraja pallida и ската Кукуева Rajella kukujevi (Orlov, Cotton, 2013, 2015Orlov, 2014). ...
... Наши результаты показали, что после фиксации интенсивность окраски дорсальной и вентральной сторон эмбрионов практически не различается. Наши исследования глубоководных североатлантических скатов (Orlov, Cotton, 2013, 2015Orlov, 2014; настоящее сообщение), основанные на изучении как свежевыловленных, так и фиксированных образцов, показывают, что и те, и другие вполне пригодны для анализа особенностей их окраски. ...
... The egg cases had characteristics typical of the genus Bathyraja (Krefft, 1956;Funicelli, 1972;Lacourt, 1979;Stehmann et al., 2001;Henry et al., 2016). Initial observations suggested that the eggs were laid by either B. richardsoni or B. pallida, as these are the only Bathyraja species previously recorded from the region (Orlov et al., 2006;Orlov & Cotton, 2013, 2016. However, the sampled egg cases did not demonstrate the taxonomically diagnostic features for B. richardsoni, such as fused case aprons (Henry et al., 2016), or the delicate, curled horns of B. pallida (Stehmann et al., 2001). ...
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A range extension for the spiny tailed skate, Bathyraja spinicauda is presented here, evidenced by an egg nursery observed atop a ridge on the Charlie Gibbs Fracture Zone along the Mid Atlantic Ridge. The species identification used an integrated taxonomic approach based on egg morphology and mtCOI barcoding of intact embryos. The egg nursery was mapped, and key environmental descriptors characterised: sedimentation, substrate type and predation risk. This egg nursery was recommended for classification as an essential fish habitat (EFH).
... The Jensen's skate Amblyraja jenseni (Bigelow and Schroeder, 1950) is common among the deeppwater skate fauna of the North Atlantic, yet until recently was not been well documented. Many species of deepp water skates were described in the second half of the last century and until recently, many of these were known only from a few specimens (Orlov et al., 2006; Orlov and Cotton, 2013; Orlov, 2014). Likewise, the Jensen's skate was described from the waters of New England and Nova Scotia as Raja jenseni in the middle of the last century (Bigelow and Schroeder, 1950). ...
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