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On the variability of skull shape in German shepherd (Alsatian) puppies.

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THE ANATOMICAL RECORD PART A 272A:460 – 466 (2003)
On the Variability of Skull Shape in
German Shepherd (Alsatian) Puppies
VEDAT ONAR1* AND HALİL GÜNEŞ2
Department of Anatomy, Faculty of Veterinary Medicine, Istanbul University,
Istanbul, Turkey
2
Department of Animal Breeding, Faculty of Veterinary Medicine, Istanbul
University, Istanbul, Turkey
1
ABSTRACT
In this study the skulls of 32 German shepherd puppies (40 –107 days
old) were examined. They were divided into three age groups (40 – 49,
50 – 69, and 70 –107 days) and the variability of their shapes was determined. Some geometrical shapes were drawn by joining the measuring
points. Angle measurements were made on these shapes, which comprised
the whole skull, neurocranium, and viscerocranium. The skull index was
further calculated in order to assess the correlation, if any, of this index
with the angle measurements. It was found that the length of the skull
increased more than the width, and, accordingly, the skull became narrower
and longer with age. Furthermore, the AZP and AZN angles widened with
age, while the ZAZ, ZPZ, NcANc, NcPNc, NcBrNc, SwNSw, and SwPSw
angles decreased. The decrease in the skull index, which was not proportionate to the age, showed that the zygomatic width did not increase as
much compared to the length of the skull. Anat Rec Part A 272A:460 – 466,
2003. © 2003 Wiley-Liss, Inc.
Key words: German shepherd dog; skull; angle; measurements;
geometry
Skulls differ more in size and shape among domestic
dogs than in any other mammalian species (Evans, 1993;
Vilà et al., 1999). The shape of the skull in dogs shows
considerable breed and individual variations in form and
size (Sisson, 1975). It is the most important criterion in
determining the standard breeds of dogs, and skull indices
and ratios are effective tools for separating and defining
the morphological types. For this reason, canine skull
forms have been the subject of many studies (Stockard,
1941; Komeyli, 1984; Brehm et al., 1985; Regedon et al.,
1991, 1992; Lignereux et al., 1991; Onar et al., 2001).
Morphometric measurements such as made in this study
can aid in classifying skulls morphologically, detecting
skull deformations, and determining the cause of those
deformations.
Many studies on canine skull morphometry have been
performed (Hidaka et al., 1998; Kauhala et al., 1998;
Onar, 1999; Onar et al., 1997, 2001; Yıldız et al., 1993),
and have yielded morphometric values relevant to the
skull shape. In addition, the skulls of adult dogs have been
analysed biometrically, and skull bases have been examined (Huber and Lüps, 1968, 1970; Lüps and Huber, 1968,
1969a,b; Huber, 1974; Lüps, 1974; Nussbaumer, 1978,
1985).
©
2003 WILEY-LISS, INC.
Other studies have dealt with genetic and environmental effects on the shape of adult dog skulls (McKeown,
1974; Jouve et al., 2001). These studies utilized angular
measurements of the whole skull in order to assess the
changes in skull shape that occur during growth. As a
result, it was concluded that environmental factors have
an insignificant effect on the skull shape of adult dogs.
However, the same factors were reported to have some
effect on the size of skull (McKeown, 1974). It has been
suggested that since dog breeds present a spectacular
intraspecific polymorphism (from Yorkshire terriers to Dobermans), the dog genome can generate various ontogenies, which makes it possible to identify the differences in
shape among these breeds (Jouve et al., 2001).
*Correspondence to: Dr. Vedat Onar, Istanbul University, Faculty of Veterinary Medicine, Department of Anatomy, 34854,
Avcilar, Istanbul, Turkey. E-mail: onar@istanbul.edu.tr
Received 24 August 2001; Accepted 13 January 2003
DOI 10.1002/ar.a.10052
VARIABILITY OF SKULL SHAPE IN ALSATIANS
Fig. 1. Measuring points and geometric shapes. a: Category 1. The
first shape as viewed from the prosthion point. b: Category 1. The
second shape as viewed from the nasion point. A, akrokranion; N,
nasion; P, prosthion; Z, zygion.
While a number of studies have been performed on the
geometrical morphometries of adult dogs, only a few have
focused on the skulls of puppies. In the present study the
skulls of German shepherd puppies, a subspecies of Alsatian canid, were studied. The morphometry of the skull
and geometry of the mandibula in German shepherd dogs
(a dolichocephalic breed) up to the age of 105 days were
examined (Onar, 1999; Onar et al., 1999).
German shepherd puppies have a wide, circular neurocranium, and a wider zygomatic width than the total skull
length at birth. As they grow older, however, some morphological changes occur in the skull, such as the manifestation of an external sagittal crest and external occipital protuberance. By making use of angular measurements, the ontogenetic variations that occur in the geometrical morphometry of skulls up to the age of 107 days
were examined in this study.
MATERIALS AND METHODS
In this study, the skulls of 32 German shepherd puppies
(40 –107 days old) were examined. Puppies from different
parents were obtained at different times from various dog
kennels (including the Academy Dog Kennel, the International Kennel K-9 Academy, and others) situated in or
around Istanbul. These puppies had died of various viral
infections in the above-mentioned kennels during the period of 1997–2000. As the number of puppies was limited,
it was not possible to carry out the survey for each sex
separately. After the soft tissues and muscles were removed, the skulls were macerated (Onar, 1999). The
skulls were divided into three age groups (40 – 49 days,
n ⫽ 14; 50 – 69 days, n ⫽ 10; and 70 –107 days, n ⫽ 8) in
order to determine the variability of the skull shapes. In
the process of forming the groups, the closeness of the
morphometric values and a small standard deviation
(S.D.) were taken into consideration.
Some geometrical shapes were drawn by joining the
measuring points on the skulls in an attempt to assess the
variations of each skull.
The measuring points were marked on the skulls as
follows (Von den Driesch, 1976; Evans, 1993; Onar, 1999)
(Figs. 1– 4):
461
Fig. 2. Measuring points and geometric shapes continued. a. 2. a:
Category 2. The first shape as viewed from the prosthion point, and the
third shape as viewed from the bregma point. b: Category 2. The second
shape as viewed from the nasion point. A, akrokranion; Br, bregma; E,
euryon; N, nasion; P, prosthion.
Akrokranion (A): central surface point on the external
occipital protuberance.
Bregma (Br): median point of the parietofrontal suture.
Ectorbitale (Ec): the most lateral point of the frontal
bone on the occipital side of the orbit.
Entorbitale (En): the naso-medial indentation of the
orbit.
Euryon (E): the most lateral point of the brain case.
Nasion (N): junction on the median plane of the right
and left nasofrontal sutures.
Prosthion (P): anterior end of the interincisive suture,
located between the roots of the upper central incisor
teeth.
Zygion (Z): the most lateral point of the zygomatic arch.
Lateral point of the nose (Sw): the most lateral point of
the caudal edge of the alveolus premolar 2.
In the process of forming the geometrical shapes, each
skull was first photographed in the dorsal position. The
pictures were then scanned and transferred to a computer.
Finally, the geometric shapes were drawn by joining the
aforementioned measuring points. The angles that
emerged from these drawings were measured. The results
from each group were evaluated separately. Thus, the
variability with age of the degrees of these angles was
inspected closely. The inspection demonstrated how the
skull of a German shepherd puppy changes as it grows to
adulthood.
The geometrical shapes were divided into four categories for analysis: 1) geometric analysis based on zygion
points, 2) geometric analysis based on euryon points, 3)
geometric analysis based on the narrowest lateral points
of the nose, and 4) geometric analysis based on the skull
index.
The findings were as follows. Category 1: Two different
geometrical shapes were formed by taking the akrokranion as the aboral point: a) the first shape as viewed from
the prosthion point (Fig. 1a), and b) the second shape as
viewed from the nasion point (Fig. 1b). Category 2: Three
462
ONAR AND GÜNEŞ
Category 3: Two different geometrical shapes were formed
in this category: a) the first shape as viewed from the
prosthion and nasion points (Figs. 3a), and b) the second
shape as viewed from the euryon, ectorbitale, entorbitale,
and zygion points (Figs. 3b). Category 4: The correlation
between skull index and angle measurements was analysed in this category.
The skull measurements used in the study were as
follows: skull length (SL) ⫽ akrokranion (A)–prosthion
(P); maximum zygomatic width (MZW) ⫽ euryon (E)–
euryon (E); and skull index (SI) ⫽ maximum zygomatic
width (E–E) ⫻ 100/skull length (A–P).
Following this categorisation, the angles of the geometrical shapes were measured and their correlation with age
was studied. To assess the variability that occurs with
age, we attempted to reveal all the features of the skull,
neurocranium, and viscerocranium in forming the geometric shapes. The statistical analysis in the study was based
on the method of Evrim and Güneş (1998).
Fig. 3. Measuring points and geometric shapes. a: Category 3. The
first shape as viewed from the prosthion and nasion points. b: Category
3. The second shape as viewed from the euryon, ectorbitale, entorbitale,
and zygion points. E, euryon; Ec, ectorbitale; En, entorbitale; N, nasion;
P, prosthion; Z, zygion; Sw, lateral point of the nose.
RESULTS
The mean values and S.D.’s of the angle measurements
of each group were determined, and the variability-withage values are presented in Table 1. The correlation of the
angle measurements to the skull index, and of one angle
measurement to another were also calculated. The statistically significant findings, which were grouped and analysed in four different categories, are presented below and
separately in Tables 2 and 3.
It was observed that the puppies in the first group had
a wide, circular neurocranium. The zygomatic width in
these puppies was wider compared to the total skull
length (Fig. 4A). Morphological changes in the second
group began to occur as the puppies grew older. The increase in the zygomatic width of the second group was not
in proportion to the skull length (Fig. 4B). In the third
group, the external sagittal crest and external occipital
protuberance began to manifest themselves in the dorsal
crania (Fig. 4C and D). The ontogenetic variations that
occurred in the skulls of these puppies are shown in schematic diagrams (drawn for each group separately) in Figure 4.
Category 1
Examination of the shapes in this category revealed
that while the angles of AZP and AZN became wider, those
of ZAZ, ZNZ, and ZPZ decreased in degree with age.
Shape “a”—prosthion taken as the point of origin. A highly negative correlation of statistical significance was found to exist among the angles of AZP, ZAZ,
and ZPZ, which remained unchanged with age.
Shape “b”—nasion taken as the point of origin.
Fig. 4. Schematic diagrams for each group separately: (A) 40-dayold puppy, (B) 50-day-old puppy, (C) 70-day-old puppy, and (D) 107day-old puppy.
Another highly negative correlation, which was only significant in the 50 – 69-day-old group, was discovered between the angles of AZN and ZNZ.
Category 2
different geometrical shapes were formed by taking the
akrokranion as the aboral point: a) the first shape as
viewed from the prosthion point (Fig. 2a), b) the second
shape as viewed from the nasion point (Fig. 1b), and c) the
third shape as viewed from the bregma point (Fig. 2a).
It was observed that in contrast to the increase in ANcP
and ANcN angles, the NcANc, NcPNc, and NcNNc angles
decreased in degree as the puppies grew older. The
NcBrNc angle, which had reached its highest degree in the
50 – 69-day-old group, dropped to its lowest in the 70 –107day-old group. However, the ANcBr angle, which re-
463
VARIABILITY OF SKULL SHAPE IN ALSATIANS
TABLE 1. Angle measurements of the skulls of the three groups
40–49 days old
ZAZ
ZNZ
ZPZ
AZN
AZP
NcANc
NcBrNc
NcNNc
NcPNc
ANcBr
ANcN
ANcP
SwNSw
SwPSw
NSwP
ZSwP
ZSwN
ZSwEn
EcEnSw
NcEcEn
SL (mm)
MZW (mm)
SI
50–69 days old
70–107 days old
n
Mean
SD.
n
Mean
SD.
n
Mean
SD.
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
14
79,25
92,56
50,30
94,09
115,22
99,67
141,53
57,51
33,80
59,40
101,12
113,26
93,66
55,81
105,26
175,32
69,96
28,40
140,44
155,01
110,10
65,72
59,69
1,378
2,970
1,372
1,554
0,942
3,939
8,855
2,612
1,690
4,088
2,857
2,393
7,458
2,395
3,652
1,797
3,641
2,593
4,481
1,656
6,488
3,974
0,778
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
77,82
91,34
47,70
95,42
117,27
95,76
146,88
53,80
30,74
58,68
105,22
116,75
89,40
54,48
108,06
174,37
66,31
29,72
140,10
158,19
126,05
71,67
56,91
3,149
2,599
1,140
2,111
1,944
3,366
7,530
3,107
1,383
2,680
2,193
1,825
5,293
1,998
3,322
1,196
2,831
1,531
2,639
3,301
5,369
2,138
1,892
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
75,56
89,25
42,63
97,59
120,85
89,28
131,33
48,55
26,03
68,10
109,49
120,75
72,38
49,43
119,10
174,53
55,36
26,66
147,93
161,06
153,14
79,63
52,27
3,105
4,420
2,940
1,813
2,380
9,946
8,332
2,488
2,329
4,957
3,488
3,538
10,056
3,195
5,240
2,981
7,235
3,331
6,369
2,061
17,201
4,816
3,209
TABLE 2. Correlation analysis of the described features in German shepherd dog (Alsatian) puppies
Age
ZPZ
AZN
AZP
NcBrNc
NcNNc
NcPNc
ANcBr
40–49
50–69
70–107
40–49
50–69
70–107
40–49
50–69
70–107
40–49
50–69
70–107
40–49
50–69
70–107
40–49
50–69
70–107
40–49
50–69
70–107
ZAZ
ZNZ
ZPZ
AZN
AZP
NcANc
NcBrNc
NcNNc
64,43*
⫺78,92**
⫺68,72**
⫺97,16***
⫺77,46*
⫺89,83***
⫺66,81*
⫺71,90*
⫺75,81**
⫺82,75*
⫺68,39**
⫺80,45**
⫺76,28*
84,65**
⫺77,54**
⫺63,94*
79,80**
58,65*
69,78*
77,11*
⫺80,42*
⫺79,50*
⫺85,96**
87,18**
79,54***
89,70***
96,18***
⫺89,60***
⫺91,80*** ⫺70,81*
⫺85,36**
*P ⬍ 0.05; **P ⬍ 0.01; ***P ⬍ 0.001.
mained constant in the first two groups, was observed to
increase in the third group of 70 –107-day-old puppies.
Shape “a”—prosthion taken as the point of origin. An analysis of the angles in this geometric shape
showed that ANcP had a highly negative correlation with
NcANc and NcPNc. The correlation remained constant
with age. In the group of 50 – 69-day-old puppies, it was
significant between ANcP and NcANc. However, the significance shifted to the correlation between ANcP and
NcPNc in the 70 –107-day-old group.
Shape “b”—nasion taken as the point of origin.
No correlation of statistical importance was observed between NcANc and NcNNc. However, a highly negative
correlation between NcANc and ANcN was significant in
the 40 – 49-day-old and 50 – 69-day-old groups. The correlation lost its significance in the 70 –107-day-old group.
Shape “c”— bregma taken as the point of origin.
NcBrNc correlated highly negatively and significantly
with ANcBr, and the degree of correlation remained the
same in all three groups. NcBrNc had a similar correlation
with NcANc in the 50 – 69-day-old group, whereas the
correlation of NcANc and ANcBr in the same group was
not found to be significant.
Category 3
It was noted in this category that the SwNSw, SwPSw,
and ZSwN angles reduced in degree with age. However,
TABLE 3. Correlation analysis of the described features in German shepherd dog (Alsatian) puppies continued
Age
ZAZ
ZNZ
ZPZ
AZN
AZP
NcANc
40–49
⫺92.39***
50–69
⫺70.84**
70–107 ⫺72.56*
81.64*
ANcP
40–49
⫺94.33***
50–69
⫺92.55***
70–107
80.81*
SwNSw 40–49
50–69
70–107
84.07**
⫺79.86*
40–49
SwPSw 50–69
72.30*
69.25* ⫺71.80* ⫺78.75**
70–107 ⫺80.52* 78.47*
NSwP
40–49
50–69 ⫺67.04*
70.55*
70–107
⫺88.68**
ZSwP
40–49
50–69
70–107 84.48**
⫺90.99**
78.60*
ZSwN
40–49
50–69
65.98*
70–107
87.41**
⫺85.46**
ZSwEn 40–49
50–69
70–107
80.50*
EcEnSw 40–49
70.48**
50–69 ⫺67.44*
72.01*
69.04*
70–107
NcEcEn 40–49
50–69
⫺69.29*
66.72*
70–107
SI
40–49
⫺58.31*
50–69
65.85* 63.23* 86.80** ⫺88.05*** ⫺78.40**
70–107
85.70**
⫺93.65**
ANcN
*P ⬍ 0.05; **P ⬍ 0.01; ***P ⬍ 0.001.
NcNNc
NcPNc
ANcBr
⫺59.88*
⫺64.44* ⫺64.22*
⫺81.13* ⫺89.64**
⫺63.37*
⫺76.46* ⫺87.44**
63.13* 62.56*
84.85**
ANcN
⫺80.96*
SwPSw
NSwP
81.12* ⫺87.86** ⫺83.89** ⫺81.74*
56.94* 58.14*
⫺81.14*
74.92*
95.97***
⫺82.63*
99.26***
⫺76.55**
63.13*
85.42** ⫺73.01*
ZSwN
ZSwEn EcEnSw
⫺84.89***
⫺74.91
97.73***
⫺93.67***
⫺89.46***
⫺93.28***
89.36**
⫺74.76*
72.38*
ZSwP
⫺83.09*
⫺94.75***
⫺96.92*** ⫺75.77**
⫺95.24***
⫺75.56*
87.57**
SwNSw
97.17***
89.65***
99.54***
⫺63.55* ⫺69.56**
74.41*
ANcP
⫺80.78*
⫺82.28*
54.30*
67.91*
⫺64.61*
75.96**
91.85**
63.98*
79.68*
⫺57.77*
⫺84.15**
80.41**
⫺84.07**
⫺92.28**
83.08*
86.45**
⫺64.30*
95.13*** 71.27*
66.54*
VARIABILITY OF SKULL SHAPE IN ALSATIANS
the increment in the angles of NcEcEn and NSwP was in
proportion to the increase in age. While the change of
ZSwP with age was insignificant, that of ZswEn (in which
the degree of the angle was largest in the 50 – 69-day-old
group) was significant. EcEnSw remained constant in the
40 – 49- and 50 – 69-day-old groups, but it increased in the
group of 70 –107-day-old puppies.
Shape “a”—prosthion and nasion taken as the
points of origin. A highly negative correlation that remained unchanged with age was observed between the
angles of SwNSw and NSwP. This was considered to be
significant. A similar correlation in the 50 – 69-day-old
group was present between the angles of SwPSw and
NSwP.
Shape “b”— euryon, ectorbitale, entorbitale,
and zygion taken as the points of origin. The correlation between SwPSw and ZSwP, which was highly
negative and therefore significant in the 40 – 49 and 50 –
69-day-old groups, was not remarkable in the 70 –107-dayold group. Similarly, SwNSw and ZSwP correlated to a
significant degree only in the third group. However, the
relationship between these two angles was of a positive
nature.
NcEcEn, SwNSw, and SwPSw correlated highly negatively with each other, as did NcEcEn with ZPZ. This
situation was observed only in the 50 – 69-day-old group.
The correlation of NcEcEn with AZP in the same group
was still noteworthy, but this time it was highly positive.
Category 4
In this category, the examination of the correlations
between the angles and skull index revealed that the
degree of the angles decreased with age.
The only significant and highly negative correlation of
the skull index was with AZP in the 40 – 49-day-old group.
However, in the group of 50 – 69-day-old puppies, the skull
index was noted to have important and highly positive
correlations with ZAZ, ZNZ, ZPZ, NcPNc, and SwPSw.
Another remarkable, though positive, correlation of the
index in the same group was with AZP and AZN.
In the third group (70 –107-day-old puppies), the index
continued to correlate highly negatively with AZP but
positively with ZPZ. However, its correlation with AZN,
which was highly negative in the second group (50 – 69day-old puppies), was not observed in the third group.
In all three groups, the index correlated highly positively with NcNNc, SwNSw, ZSwP, ZSwN, and ZswEn,
and negatively with ANcBr, ANcN, AncP, and NSwP.
DISCUSSION
Dog breeds present a spectacular intraspecific polymorphism. The shape and morphometry of dog skulls are
therefore important parameters for determining morphological types. Researchers can examine geometric morphometries to determine the skull forms of adult dogs, as
well as to assess changes in shape that occur during development. By taking an ontogenetic approach, investigators can observe these shape changes until the formation
of the adult skull is complete. During this period of time,
angular measurements made on skulls can play a significant role in the appraisal of growth processes.
It was observed in our study that German shepherd
puppies start out in life with a wide, circular neurocra-
465
nium. It was also noted that some morphological changes
in their skulls, such as the manifestation of the external
sagittal crest and external occipital protuberance, occur
between birth and maturity. These changes in shape resulted in a decrease of the skull index.
The high skull index in the group of 40 – 49-day-old
puppies was due to a wider maximum zygomatic width
compared to the total skull length. However, as the puppies grew older, the former value did not increase in proportion to that of the total skull length, which explained
the decrease in the skull index. Subsequently, the lowest
skull index was observed in the 70 –107-day-old group.
Although these skull indices were greater than those in
dolichocephalic breeds (Evans, 1993), it was ascertained
that they tended to decrease as the puppies grew older.
This indicated that the puppy skulls developed longitudinally. The angular measurements and their relationships
to each other correlated with the fact that the noses of
German shepherds become longer as the dogs develop.
The geometrical analysis based on the zygion points
(Fig. 1a and b) revealed that the increase in the zygomatic
width, which was in proportion to age, was less than that
of the skull length. On the other hand, the decrease in
ZAZ, ZPZ, and ZNZ with age, and their highly positive and
significant correlation with the skull index, made it clear
that the skull length increased more compared to its
width. This demonstrated that the shape of the skull
shifted to that of a narrow, long one. In support of this
observation, the AZP and AZN angles extended as the
puppies grew older.
A geometrical analysis based on both the left and right
euryon points (Fig. 2a and b) showed that the degrees of
the angles of NcANc, NcPNc, NcNNc, and NcBrNc declined with age, and that the skull index correlated highly
positively and significantly with NcPNc and NcNNc. This
resulted in the neurocranium having a narrow, long appearance in line with the lengthened skull. That the angle
degree of NcBrNc narrowed with age indicated that the
bregma point proceeded forward as a result of the altered
appearance (narrower and longer) of the neurocranium.
When the geometrical shape drawn by joining the narrowest lateral points of the nose was analysed (Fig. 3a and
b), it was noted that as a result of the decrease in SwNSw
and SwPSw with age, the degree of NSwP widened, which
resulted in the viscerocranium having a narrow, long
shape, both orally and aborally. Furthermore, the highly
positive correlation between the skull index and SwNSw
and SwPSw, which showed that the increase in skull
length was greater than that of the zygomatic width, was
another indicator that the viscerocranium developed
lengthwise and narrowed as it did so.
So far, the skull base has been the only point of origin
for examinations of alterations in skull shape. A biometrical analysis of curvatures in the skull base of adult dogs
has been performed (Nussbaumer, 1985), and variations
in the length of the palatine bone with age have also been
shown in newborn puppies (Nussbaumer, 1978). However,
the changes that occur in the skulls of puppies have not
been studied as a whole.
Data obtained from both the dorsal and ventral crania
play a part in investigations of the growth processes that
occur in the skull. The development of the basiocranium,
in particular, has a great influence on the overall growth
trajectories of the neurocranium. However, in this study
we have only discussed changes in the geometrical morphometry of the dorsal crania. It has been reported that
466
ONAR AND GÜNEŞ
changes in the morphology of the dorsal crania may have
an effect on craniofacial development (Onar, 1999). Therefore, we believe that the observed angular changes in the
dorsal crania may in part explain the changes that occur
in the shape of the dog skull during growth.
In our previous study (Onar, 1999), a morphometric
analysis of the skull of German shepherd dogs, which is a
dolichocephalic breed, was made, and the changes with
age of the craniometric measurements were given in detail. Below are the findings that suggest that the skulls of
German shepherd puppies will have a dolichocephalic appearance and become narrower and longer as the puppies
reach adulthood:
Geometrical variations in the shape of the skull occur
during the dolichocephalic development of German
shepherd puppies, as indicated by angle measurements.
German shepherd puppies have a wide, circular neurocranium.
Previous morphometric evaluations support the notion
that the development of the skull of a German shepherd
puppy is of a dolichocephalic nature (Onar, 1999).
We hope this study will be of some assistance to those
who may wish to examine the ventral crania and the
development of the skull as a whole.
ACKNOWLEDGMENT
The authors thank Mr. Cüneyt Bademcioğlu for his
invaluable contribution to the translation of this article.
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