39

НАУКА ЗА ГОРАТА, КН. 3, 2007FOREST SCIENCE, No 3, 2007

WOOD MICE (APODEMUS SYLVATICUS LINNAEUS, 1758 AND APODEMUS FLAVICOLLIS MELCHIOR, 1834)

FROM BULGARIA: CRANIOMETRIC CHARACTERISTICS and species discrimination

Tsenka Chassovnikarova, Georgi MarkovInstitute of Zoology – Sofia

Bulgarian Academy of Sciences

abstract: The craniometric diversity of wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse in the southeast part of the Balkan Peninsula has been characterized on the basis of biochemical-genetically determined samples. Craniometrical characteristics of both species show similar absolute variability of their corresponding parameters. Cranial sexual dimorphism in both species has been registered. On the basis of established craniometrical characteristics a discriminating function for their species diagnostics has been deduced. They complete 100% correct definition of the analyzed individuals in accordance with the preliminary known one from the biochemical-genetic analysis.

Key words: A. sylvaticus, A. flavicollis, discriminate keys, craniometry, wood mouse

introduction

Morphological diagnostics of wood (Apodemus sylvaticus Linnaeus, 1775) and yellow necked (Apodemus flavicollis Me l c h i o r, 1834) mouse, in the south part of their genus areal in Europe is heavily complicated by morphological parallelism, typical of West Palaearctic subgenus Sylvaemus Ognev, 1924. Simple diagnostics of the species is hampered by strong opposite geographical variability of external size characteristics, peculiar to these wood mice (N i e t h h amm e r, 1969).

Biochemical analyses of wood mice have proven that the species could be uniquely differentiated by their izoenzyme characteristics (G emm e k e, 1980; F i l i p p u c c i et al., 1989; B r i t t o n – D a v i d i e n et al., 1991; Hartl et al., 1991). This biochemical genetic verification has shown that some individuals, ‘typical’ for the species, according to the classical morphological description, in fact belong to the other species.

The somatometrical and craniometrical descriptions of these species have been object of regional investigations in Europe, and different criteria of their differentiation have been used (S t e i n e r, 1968; Van den S t r e a t e n, 1976; F i l i p p u c c i et al., 1984; P o p o v, 1993; K r y š t u f e k, S t o j a n o v s k i, 1996; Ö z k a n, K r y s r u f e k 1999; R e u t e r et al., 1999).

40

The aim of the present work is, on the basis of biochemical-genetically determined individuals of wood (A. sylvaticus) and yellow necked mouse (A. flavicollis), to characterize the craniometrical diversity of these species in Bulgaria. On the basis of established craniometrical characteristics a discriminating function for their species diagnostics is to be deduced.

material and methods

Wood mice (90 individuals) from wood and field biotopes in Bulgaria (Fig. 1) have been analysed:

Wood biotopes: 1. North Trakya, old oak forest (42º12’N; 25º19’E; 210 m a.s.l.); n=19

individuals (10 males and 9 females); 2. Vitosha mountain (beech woods, artificial coniferous plantations

(42º33’N; 230º15’E, 1300 m a.s.l.); n=22 individuals (9 males and 13 females);

3. Central Balkan (mixed broad-leaved forest (42058’N; 23 º46’E, 350 m a.s.l.); n=20 individuals (15 males and 5 females).

Field biotopes:4. Sofia’s field (foothill meadows 42º42’N; 23º20’E, 580 m a.s.l.); n=11

individuals (3 males and 8 females); 5. Mizia plain (open landscapes, cultivated areas (43º25’N; 24º38’E,

160 m a.s.l.); n=18 individuals (15 males and 3 females). All individuals studied have been adult specimens of 9-15 months,

corresponding to III and IV age groups. The age of each specimen has been determined according to the degree of teeth wearing out (Felten, 1952; Adamczewska-Andzeewska, 1967).

The species determination of the analysed wood mice has been carried out by biochemical-genetic analysis through the proposed by Hartl et al. (1991) diagnostic enzyme systems: lactate dehydrogenase (LDH, E.C. 1.1.1.27), superoxid dismutase (SOD, E.C. 1.15.1.1) and nucleosid phosphorylase (NP, E.C. 2.4.2.1).

Kidney, liver and heart were used for screening of diagnostic enzymes. Preparations of tissue extracts, horizontal starch gel electrophoresis and enzyme specific standing procedures were performed according to routine methods (H a r t l, H o g e r, 1986). The interpretation of band-pattern followed the principles outlined by H a r i s, H o p k i n s (1976) and H a r i s (1980).

Biochemical-genetically determined specimens have been characterized by 61 craniometrical traits (Fig. 2). Measurements have been made with a calliper-gauge with an allowance of 0.1 mm (traits 1 to 16 and from 19 to 29) and with binoculars with an allowance of 0.01 mm (traits 17 and 18 and from 30 to 61).

41

Statistical evaluation of craniometrical variability of both species studied is characterized by standard statistical characters – average value of the parameter ( X ), and standard deviation (S.D.). The verification of equality of the average values of craniometrical traits studied in the formed sex and species groups of wood mice has been carried out through t-criterion of Student. Species craniometrical diagnostic key has been carried out by stepwise discriminating analysis, according the algorithm of statistical package programme WinStat, 1994.

results and discussion

Species determination of all specimens analysed by three diagnostic enzyme systems (LDH, SOD, NP) is synchronic and defines the specimens as belonging to one of the two species – A. sylvaticus (n=45 individuals) and A. flavicollis (n=45 individuals). The analysis of biochemical genetic investigations on wood mice studied has established the presence of both species in two types of biotopes in Bulgaria – A. sylvaticus in the samples from field biotope – Mizia plain (biotope 5) and in forest biotope- North Trakya (biotope 1) and A. flavicollis in the samples from forest biotopes – Central Balkan (biotope 3) and Vitosha Mountain (biotope 2) and in field

12

Fig.1

Fig. 1. Geographic location of the studied populations: 1 – North Trakya, 2 – Vitosha mountain, 3 – Central Balkan, 4 – Sofia’s field, 5 – Mizia plain

42

Fig. 2. Points of measurements for craniometric description in the species wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse. Skull and mandible characters used: V1-total skull length, V2- condylobasal length,V3-basal length, V4- distance between os nasale anterior and parietale posterior,V5-lenght of nasale, V6-distance between foramen infraorbitale and condylus occipitale, V7- diastema, V8- lenght of maxillar teeth row (alveolare), V9- rostrum breadth, V10- distance between foramen infraorbitales, V11- zygomatic breadth, V12- postorbital breadth, V13- skull breadth behind os zugomaticus, V14- mastoid breadth, V15- foramen magnum breadth, V16- foramen magnum height, V17- bullae ossae breadth, V18- bullae ossae length, V19- palatine dururm breadth, V20- height of the skull through bullae ossae, V21- height of the skull between bullae ossae, V22- height of the face part of the skull, V23- total mandible length I, V24- total mandible length II, V25- mandible alveoli teeth – row length, V26- mandible height I, V27- distance between procesus coronoideus and procesus condyloideus, V28- mandible height II, V29- width of ramus mandibularis, V30- meatus auditorius externus length, V31- meatus auditorius externus bredth, V32- anterior palatine foramen length, V33- distance between alveoli incisivi lateralis, V34- distance between posterior palatal fissures, V35- distance between foramen ovale, V36- distance between bullae ossae lateralis, V37- palatine durum length, V38- distance between palatine durum posterior and foramen occipitalis, V39- width of zygomatic arch (upper part), V40- width of mallax process (anterior part), V41- anterior-posterior diameter of foramen postorbitale, V42- sutura frontalis length, V43- sutura sagittalis length, V44- os interparietale length, V45- distance between suture coronare lateralis, V46- os parietale length I, V47- os parietale length II, V48- M1 breadth, V49- M2 breadth, V50- M3 breadth, V51- M1 length, V52- M2 length, V53- M3 length, V54- mandible coronary teeth – row length, V55- M1 breadth, V56- M2 breadth, V57- M3 breadth, V58- M1 length, V59- M2 length, V60- M3 length

43

biotope – Sofia field (biotope 4) (Fig. 1). Biotope distribution of the two species of wood mice in Bulgaria shows that in open landscapes situated at low sea level up to 800 m A. sylvaticus species is generally detected, while in wood biotopes, which have relatively higher sea level height (from 800 to 1900 m) – the species A. flavicollis. From all the investigated biotopes both kinds of species are sympatric only at the foothill of central Balkan Mountain.

Craniological characteristics of both species, deduced on the basis of craniometrical description, show similar absolute variability of their corresponding parameters (Table 1). The detailed analysis of intraspecies’ craniometrical characteristics of wood mice has shown that by some of the applied parameters they have a definite craniometrical sex dimorphism. In A. sylvaticus by 13 traits (21.3%) has been realised a statistically significant difference in the mean values of the analysed specimens (Fig. 3a). Тhe male individuals have higher mean values in 92.3% of them. In A. flavicollis intraspecies sex dimorphism of the analysed morphometrical parameters has been proved in 9 traits (14.75%). In all these cases male specimens have higher average values of the investigated parameters (Fig. 3b).

The comparison of craniometrical parameters in identical sexes of A. sylvaticus and A. flavicollis has shown the presence of statistically significant differences in both sexes. In female individuals 53 of the parameters (86.88%) have statistically significant differences. 94.34 % of A. flavicollis individuals have higher parameter values (Fig. 4a). The comparison of the mean values of investigated parameters in male individuals of both species (Fig. 4b) shows that in 45 parameters (73.77%) there is statistically proven difference. In 93.33% of these parameters bigger sizes are registered in the cranium of A. flavicollis.

Craniological characteristics of wood mice in Bulgaria illustrate their similar absolute cranial variability. At the same time is expressed clearly defined sexual dimorphism in both species. The latter is clearer in A. sylvaticus. The equal sexes of both species show clearly expressed difference in the craniological size. In both sexes the representatives of A. flavicollis show higher values of the majority of investigated parameters.

The expression of these species’ and sexual differences in wood mice – A. flavicollis and A.sylvaticus in South-Eastern Europe is in contrast with the widespread opinion that they have almost identical metric characteristics and lack of sexual craniometrical dimorphism. Probably the strong craniological similarity in other parts of their European areal is the reason some authors (Van den Brink, 1969; Saint-Girons, 1973) to accept that species diagnostics of these two species is not possible on the ground of craniometrical signs only.

The check of species determination of previously genetically determined wood mice from Bulgaria on the basis of morphological criteria defined about both species (A. sylvaticus and A. flavicollis) in other parts of their

44

Variable

Apod

emus

sylva

ticus

Apod

emus

fla

vico

llis

Variable

Apod

emus

sylva

ticus

Apod

emus

fla

vico

llis

Male

N=

17Fe

male

N=

15M

ale

N=

17Fe

male

N=

17M

ale

N=

17Fe

male

N=

15M

ale

N=

17Fe

male

N=

17

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

V125

.96

1.08

25.10

0.69

27.24

0.91

26.49

1.04

V14

V14

11.16

0.42

10.97

0.27

11.44

0.42

11.35

V223

.81

1.03

23.13

0.90

24.69

0.89

24.16

0.93

V15

V15

4.62

0.17

4.53

0.19

4.75

0.18

4.73

V319

.89

1.83

19.23

0.89

20.61

0.87

19.95

1.17

V16

V16

4.29

0.18

4.21

0.15

4.32

0.21

4.33

V425

.41

1.01

24.56

0.65

26.65

0.91

25.92

1.08

V17

V17

4.67

0.36

4.65

0.32

5.05

0.26

4.97

V59.82

0.66

9.39

0.71

10.47

0.56

9.79

0.56

V18

V18

5.51

0.39

5.42

0.39

7.18

0.45

7.12

V618

.52

0.88

17.89

0.50

19.21

0.80

18.79

18.79

V19

V19

3.72

0.19

3.75

0.25

3.77

0.18

3.86

V77.12

0.45

6.82

0.33

7.21

0.39

7.08

7.08

V20

V20

9.36

0.38

9.14

0.33

9.68

0.32

9.66

V84.14

0.31

4.13

0.29

4.15

0.11

4.22

4.22

V21

V21

7.98

0.32

7.79

0.30

8.04

0.24

8.01

V93.87

0.24

3.78

0.14

4.21

0.30

4.16

4.16

V22

V22

6.69

0.38

6.49

0.53

6.95

0.37

6.85

V10

3.33

0.30

3.22

0.13

3.53

0.19

3.57

3.57

V23

V23

13.50

0.77

13.06

0.44

14.25

0.52

13.85

V11

13.19

0.69

12.82

0.42

13.78

0.55

13.38

13.38

V24

V24

11.79

0.83

11.37

0.52

12.26

0.61

12.06

V12

4.14

0.17

4.01

0.18

4.17

0.41

4.26

4.26

V25

V25

3.86

0.18

3.86

0.21

4.11

0.42

4.17

V13

11.75

0.41

11.49

0.26

11.88

0.32

11.72

11.72

V26

V26

6.13

0.40

6.02

0.35

6.35

0.46

6.25

V27

5.41

0.42

5.45

0.34

5.71

0.28

5.62

0.27

V44

3.03

0.35

2.91

0.17

3.11

0.21

3.15

0.29

V28

6.24

0.60

5.84

0.39

6.87

0.46

6.58

0.41

V45

7.40

0.52

7.12

0.34

7.79

0.50

7.72

0.51

V29

4.29

0.40

3.95

0.25

4.44

0.24

4.26

0.30

V46

8.41

0.23

8.39

0.22

8.60

0.24

8.46

0.34

table 1

Var

iatio

n of

61

scull v

ariabl

es o

f woo

d (A

. sylv

aticus

) an

d ye

llow n

ecke

d (A

. fla

vico

llis) m

ouse

in B

ulga

ria

45

table 1

Con

tinue

d

Variable

Apod

emus

sylva

ticus

Apod

emus

fla

vico

llis

Variable

Apod

emus

sylva

ticus

Apod

emus

fla

vico

llis

Male

N=

17Fe

male

N=

15M

ale

N=

17Fe

male

N=

17M

ale

N=

17Fe

male

N=

15M

ale

N=

17Fe

male

N=

17

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

X [mm

]SD

V30

2.35

0.17

2.35

0.13

2.35

0.16

2.35

0.17

V47

7.48

0.33

7.28

0.28

7.23

0.32

6.88

0.46

V31

2.39

0.22

2.31

0.14

2.36

0.16

2.44

0.15

V48

1.32

0.11

1.35

0.05

1.47

0.06

1.47

0.06

V32

5.81

0.27

5.76

0.33

5.61

0.27

5.52

0.25

V49

1.26

0.09

1.26

0.08

1.39

0.08

1.35

0.09

V33

2.68

0.22

2.61

0.21

2.87

0.19

2.87

0.17

V50

0.93

0.08

0.95

0.07

1.06

0.07

1.04

0.05

V34

1.82

0.10

1.74

0.11

1.85

0.12

1.78

0.12

V51

1.89

0.10

1.97

0.10

2.11

0.07

2.08

0.10

V35

6.41

0.21

6.35

0.16

6.47

0.26

6.54

0.25

V52

1.26

0.11

1.25

0.10

1.45

0.11

1.41

0.11

V36

11.56

0.43

11.39

0.25

11.89

0.33

11.69

0.40

V53

0.98

0.09

0.97

0.07

1.11

0.09

1.06

0.06

V37

11.77

0.52

11.49

0.37

11.82

0.48

11.63

0.64

V54

0.27

0.06

0.30

0.06

0.21

0.06

0.19

0.07

V38

9.27

0.58

8.92

0.40

9.70

0.41

9.49

0.51

V55

1.18

0.08

1.16

0.06

1.28

0.06

1.28

0.07

V39

0.92

0.13

0.86

0.13

1.06

0.17

1.05

0.12

V56

1.17

0.06

1.14

0.06

1.25

0.05

1.24

0.09

V40

1.05

0.12

1.02

0.10

1.23

0.11

1.19

0.11

V57

0.96

0.07

0.96

0.06

1.09

0.07

1.09

0.06

V41

9.62

0.34

9.45

0.27

9.97

0.40

9.85

0.49

V58

1.85

0.09

1.84

0.09

1.98

0.11

1.96

0.08

V42

9.78

0.47

9.55

0.40

9.59

0.89

9.64

0.54

V59

1.29

0.13

1.26

0.07

1.35

0.07

1.34

0.06

V43

4.39

0.27

4.38

0.24

5.05

0.47

5.02

0.51

V60

1.03

0.09

0.99

0.07

1.11

0.08

1.09

0.08

46

European areal has shown their unreliable determination ability.Booth discrimination functions deduced by Van den Streaten

(1976) for differentiation of wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse in Belgium, applied on preliminary genetically determined

14

t-val

ue

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V1V3

V5V7

V9V11

V13V15

V17V19

V21V23

V25V27

V29V31

V33V35

V37V39

V41V43

V45V47

V49V51

V53V55

V57V59

V61

3a

t-val

ue

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V1V3

V5V7

V9V11

V13V15

V17V19

V21V23

V25V27

V29V31

V33V35

V37V39

V41V43

V45V47

V49V51

V53V55

V57V59

V61

3 b

Fig. 3

Fig. 3. Sexual dimorphism by cranial measurements of wood (A. sylvaticus) (3a) and yellow necked (A. flavicollis) mouse (3b)

4715

t-val

ue

-12

-10

-8

-6

-4

-2

0

2

4

6

V1V3

V5V7

V9V11

V13V15

V17V19

V21V23

V25V27

V29V31

V33V35

V37V39

V41V43

V45V47

V49V51

V53V55

V57V59

V61

4a

t-val

ue

-14

-12

-10

-8

-6

-4

-2

0

2

4

V1V3

V5V7

V9V11

V13V15

V17V19

V21V23

V25V27

V29V31

V33V35

V37V39

V41V43

V45V47

V49V51

V53V55

V57V59

V61

4b

Fig.4 Fig. 4. Verification of equality of average value in cranial measurements by female (4a) and male (4b) individuals of wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse

48

specimen on the territory of Bulgaria, do not define correctly their species affiliation. The first function including morphometrical characteristics – length of foramina incisiva, length of diastema, length of upper molars row and thickness of incisor, defines correctly only 25% of the genetically determined as A. sylvaticus individuals and assigns all the rest to A. flavicollis, or, only 55% are correctly defined specimens. The correctly defined ones by second discrimination function, containing craniometrical (length of foramina incisiva, length of diastema) and teeth measurements (length of upper molars row and thickness of incisor) are 23% of the specimens of A. sylvaticus and 53% of A. flavicollis.

The species determination of individuals from Bulgarian genetically determined samples, according to the offered by S t e i n e r (1968) craniological trait (position of front premolar aperture towards the imaginary line connecting the front end of the roots of both front molars (M1)), correctly defines 62% of the specimens to the group of A. sylvaticus and only 38 % to the group of A. flavicollis.

The application of deduced by F i l i p p i c c i et al. (1984) species’ determination morphometrical index (MI= (length of upper molar row + length of velum bridge + interorbital width) on Bulgarian genetically determined samples of wood mice, shows total lack of correspondence between the preliminary defined species. All the individuals that have been genetically defined as A. sylvaticus and A. flavicollis are classified as only one species.

The deduced by P o p o v (1993) discrimination function for species definition of wood mice in Bulgaria including the morphometrical index of F i l i p p u c c i (1982), two new craniometrical indexes, as well as somatometrical parameters (length of tail and height of cochlea), defines the 90 genetically determined specimens (45 specimens from A. sylvaticus and 45 specimens of A. flavicollis ) only as A. sylvaticus.

The discriminated function, offered by R e u t e r et al. (1999), is evaluated for simultaneously craniometrical determination of three morphologically very similar species – A. sylvaticus, A. flavicollis and A. alpicola in samples from Central and Western Europe. It defines the 97% of individuals with unknown species affiliation from these parts of Europe. This discriminant key, applied on Bulgarian genetically determined samples of wood mice, defines the 62% from the genetically determined as A. sylvaticus and 73% from the genetically determined as A. flovicollis.

The comparative analysis of correctly defined species’ affiliation of wood mice in South-Eastern Europe through morphological criteria, deduced in other parts of their European areal, shows that these are not applicable for the whole European species areal. Including of somatometrical parameters with great variability in the morphological keys, leads to the same result.

The registered cranial sexual dimorphism in wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse in Bulgaria, as well as the statistically

49

proven intersexual craniological differences in both species, necessitates that the deduction of species’ determination craniological complexes by wood mice should take into consideration their craniometrical differentiation.

The deduced on the basis of genetically determined samples of both species A. sylvaticus and A. flavicollis from Bulgaria determination craniometrical key complete 100% correct definition of the analysed individuals in accordance with the preliminary known one from biochemical-genetic analysis. The species’ determination craniometrical functions, that serve as sexual and species definition of genetically determined wood mice from Bulgaria, includes 33 craniometrical parameters (Table 2). The relatively large number of parameters included could complicate to an extent the practical application of this determination complex in mass definition of craniological material with an unknown sexual and species appurtenance. This complication is avoided by the use of deduced species’ determinative (Table 3, 4) for the application of which it is necessary to preliminarily know the sexual appurtenance of specimen species’ appurtenance of which will be defined. The species determination using these craniometrical complexes should be done in the followed descriptive algorithm.

According to the accepted algorithm of applied modification of forward stepwise analysis the definition of species’ appurtenance of an unknown specimen as one of the two types – A. flavicollis or A. sylvaticus should be done in the following succession:

1. Calculation of both craniometrical functions – Y A. sylvaticus and Y A.flavicollis, using the real individual craniometrical values of the analysed specimen.

2. The results from both craniometrical functions – Y A. sylvaticus and Y A. flavicollis are compared and the analysed individual belongs to the species for which calculated value is higher.

conclusions

The 100% correct coincidence between morphological and biochemical definition of wood mice species demonstrates that the craniometrical multidimensional description, used in proposed in this investigation craniometrical keys, is the applicable way of their species’ morphometrical differentiation and determination in the regions they sympatrically inhabit in South-Eastern Europe.

Statistically significant results for the species’ discrimination of individuals of A. sylvaticus and A. flavicollis to the known from their biochemical-genetically determined species’ appurtenance show that the preliminary correct definition of their species’ affiliation, sex and age of specimens, forming the initial groups for comparative craniometrical analysis of wood mice, are of major importance for the correct craniometrical description of each species and sex.

50

table 2 Species’ determination craniometric functions for sexual and species definition of wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse from Bulgaria (Wilks’ Lamda:

0.0241; p<0.0000; Clasifications: 100% correct for all groups)

Variable A. sylvaticus, female A. sylvaticus, male A. flavicollis, female A. flavicollis, male

V18 -69.38 -67.26 -47.69 -45.94V47 -28.11 -22.26 -41.65 -34.66V48 268.95 213.65 277.42 233.57V29 -242.30 -227.71 -265.83 -272.63V32 -70.77 -74.54 -121.33 -123.36V5 9.06 8.43 17.18 16.65V51 404.29 346.20 475.83 471.17V54 -150.31 -199.37 -345.35 -363.91V1 56.36 40.42 60.24 64.69V27 -84.31 -94.64 -109.40 -109.99V14 155.31 138.69 135.34 .71V23 196.92 189.63 236.95 247.32V24 -219.57 -209.48 -244.44 -252.05V61 38.62 8.01 94.01 95.32V44 -225.94 -203.71 -257.28 -261.18V45 -63.11 -55.50 -71.07 -71.10V34 -430.19 -421.40 -486.47 -486.11V53 268.15 289.73 325.79 379.66V31 17.90 24.10 32.45 22.578V15 109.93 127.07 122.45 123.05V9 286.87 272.68 304.19 304.79V38 -6.13 -1.51 14.63 26.14V52 -22.23 -22.24 23.31 40.55V13 118.22 116.29 145.23 146.34V39 79.82 64.12 139.51 124.80V2 105.55 109.00 112.63 100.37V8 55.42 65.64 46.99 39.38V11 -158.70 -142.37 -174.36 -166.15V35 237.14 225.77 235.92 218.57V49 -280.26 -249.20 -329.34 -303.97V4 -26.53 -13.61 -32.77 -29.86V50 119.08 78.28 157.41 171.55V30 168.89 147.29 162.41 160.23Constant -2534.34 -2489.18 -2757.9 -2775.02

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reFerencesA d am c z e w s k a – Andrzeewska, K. 1967. Age reference model for Apodemus flavicollis.-

Ekologia Polska, ser. A, 15, 41, 787-790.B r i t t o n-D a v i d i a n, J., M. Vahdati, F. Benmehdi, P. Gros, V. Nance, H. Croset, S.

Guerassimov, C. Triantaphyllidis. 1991. Genetic differentiation in four species of Apodemus from Southern Europe: A. sylvaticus, A. agrarius, A. flavicollis, A. mystacinus (Muridae, Rodentia). – Zeitschrift fuer Saeugetierkunde, 56, 25-33.

F e l t e n, H.1952. Untersuchungen zur Oekologie und Morphologie der Waldmaus (Ap. sylvaticus) und der gelbhalsmaus (Ap. flavicollis) in Rein-Main Gebiet.- Bonner Zoologische Beitraege, 3, 187-206.

F i l i p p u c c i, M. G., M. Cristaldi, L. Tizi, L. Contoli.1984. Dati morfologici e morfometrici in populationi di Apodemus (Sylvaemus) dell’Italia Quatro-meridionale determinati elektroforeticamente.- Ricerche di Biologia della Selvaggina, 9, 85-126.

F i l i p p u c c i, M. G., Sh. Simson, E. Nevo. 1989. Evolutionary biology of the genus Apodemus in Israel: Allozymic and biometric analysis with description of a new species Apodemus hermonensis. – Bollotino di Zoolia, 56, 4, 361-376.

G emm e k e, H.1980. Proteinvariation und Taxonomie in der Gattung Apodemus (Mammalia, Rodentia).- Zeitschrift fuer Saeugetierkunde, 45, 348-365.

H a r r i s, H., D. Hopkins. 1976. Hand – book of enzyme electrophoresis in human genetics. North Holland, PC, 252.

H a r r i s, H. 1980. The principles of human biochemical genetics. Amsterdam, Elsevier/North Holland. 143

H a r t l, G. B., H. Hoger. 1986. Biochemical variation in purebred and crossbred strains of domestic rabbits (Oryctolagus cuniculus L.).- Genetics Research, Cambridge, 48, 27-34.

H a r t l, G. B., F. Suchentrunk, R. Willing, J. Markowski, H. Ansorge. 1991. Incinsistency of biochemical evolutionary rates affecting allozyme divergence within the Genus Apodemus (Muridae, Mammalia). – Biochemical Systematic and Ecolology, 20 (4), 363-372.

F i l i p p u c c i, M.G., Cristaldi M., Tizi L., Contoli L. 1984. Dati morfologici e morfometrici in popolazioni di Apodemus (Sylvaemus) dell’Italia centro meridionale determinati elettroforeticamente. In: Recenti acquisizioni sul genere Apodemus in Italia. Atti I Seminario dell’Ass. Teriologica Romana. Roma 19/03/1982. Supplemento Ricerche di Biologia della Selvaggina, IX (num.unico), 127-142.

Table 3Species’determination craniometric function for male individuals of wood

(A. sylvaticus) and yellow necked (A. flavicollis) mouse from Bulgaria

Wilks’ lamda: 0.156; approx. F (2,29) = 78,25; p<0.0000; clasifications: 100% correct for all groups

Variable A. sylvaticus A. flavicollisV18 16.29 27.43V32 71.53 63.12

Const. -253.39 -276.18

table 4 Species’determination craniometric function for female individuals

of wood (A. sylvaticus) and yellow necked (A. flavicollis) mouse from Bulgaria

Wilks’ lamda: 0.171; approx. F (2,31) = 74,99; p<0.0000; clasifications: 100% correct for all groups

Variable A. sylvaticus. A. flavicollisV18 9.70 19.20V32 60.97 52.35

Const. -202.53 -213.53

52

F i l i p p u c c i, M.G., Sh. Simson, E. Nevo, 1989. Evolutionary biology of the genus Apodemus in Israel: Allozymic and biometric analysis with description of a new species Apodemus hermonensis. – Boll. Zool., 56, 4, 361-376.

K r y š t u f e k, B., L. Stojanovski, 1996. Apodemus sylvaticus stankovici is a synonym of Apodemus flavicolli – Folia zoologica, 45, 1-7.

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S t e i n e r, H. M. 1968. Untersuchung über die Variabilitat und Bionomie der Gattung Apodemus (Muridae, Mammalia) der Donau-Auen von Stockerau (Niederösterreich).- Zeitschrift der Wissenschaftlichen Zoologie, 177, 1-96.

Van den B r i n k s, F. H. 1957. Die Saeugetiere Europas, Verlag Parey Hamburg-Berlin, 146. Van den S t r e a t e n, E.1976. Maatgegevens van Apodemus sylvaticus (Linnaeus, 1758) en

Apodemus flavicollis (Melchior, 1834) in Belgie. – Lutra, 18, 15-22.

горските мишки (APODEMUS SYLVATICUS linnaeus, 1758 and APODEMUS FLAVICOLLIS MELCHIOR, 1834) в България:

краниометрична характеристика и видово разграничаване

Ц. Часовникарова, Г. МарковИнститут по зоология – София, Българска академия на науките

( р е з ю м е )

Характеризирано е краниометричното разнообразие на обик-новената (Apodemus sylvaticus L., 1758) и жълтогърлата (Apodemus flavicollis M е l c h. 1834) горски мишки в югоизточната част на Балкан-ския полуостров на основата на биохимично-генетично детермини-рани индивиди. Двата вида имат сходни стойности на абсолютната изменчивост на краниалните признаци. Установен е статистически значим краниален полов диморфизъм и при двата вида. На основата на установените краниални характеристики е създадена дискрими-нантна функция за видова диагностика, която осигурява 100% вярна видова детeрминация, съответстваща на предварителната генетич-на детерминация.

ключови думи: A. sylvaticus, A. flavicollis, дискриминантни ключове, краниометрия, горска мишка