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Mandibles and molars of the wood mouse, Apodemus sylvaticus (L.)

Table 1 Localities and groups used in statistical analyses, with latitude and number of items analysed
Group M/I GENET Country Locality Coll Latitude M1 Md

FR-IEV M WEUR France St Me ´en MHNH 48.2 6 6
FR-CH M WEUR France Lignie `res MHNH 46.8 10 11
FR-LA M WEUR France Marais Poitevin JRM 46.8 2 1
Puceul MHNH 47.6 21 21
FR-OL I WEUR France Ole ´ron JRM 45.9 15 15
FR-RE I WEUR France Re ´ JRM 46.2 7 6
FR-YEU I WEUR Yeu JRM 46.7 1 1
FR-NM I WEUR Noirmoutier JRM 47.0 3 3
FR-MTP M WEUR France Montpellier JRM 44.0 14 14
FR-S M WEUR France Cap Lardier JRM 43.3 6 4
Esterel JRM 43.4 2 1
La Penne JRM 43.9 4 4
Ce ´vennes JRM 44.4 3 2
FR-PORQ I WEUR France Porquerolles JRM 43.0 11 8
FR-PTCR WEUR Port Cros JRM 43.0 7 4
CO I IBK France Bonifacio JRM 41.4 3 3
Fango JRM 42.4 5 5
IT-CAL M IBK Italy Gambaria JRM 38.2 2 3
IT-TARQ IBK Tarquinia JRM 42.3 32 25
IT-GROS IBK Grosseto JRM 42.8 6 5
IT-SARD I IBK Italy Sardinia JRM 40.9 3 2
ELBA I IBK Elba JRM 42.8 1 1
SIC-FIC I SIC Italy Ficuzza JRM 37.7 7 6
SIC-GRAT I SIC Grateri JRM 38.0 8 9
SIC-M I SIC Marettimo JRM 38.0 1 1
PYR M WEUR France Banyuls JRM 42.5 10 6
Spain Figueras JRM 42.3 5 5
Spain Fabian JRM 42.6 4 4
SP-MUR M WEUR Spain Murcia JRM 38.0 15 15
SP-ALC M WEUR Spain Alcoy JRM 38.7 10 10
SP-N WEUR Nogais JRM 42.8 3 3
Posada JRM 43.2 3 3
IBIZ I WEUR Spain Ibiza JRM 38.9 9 9
M1, first upper molar; Md, mandible; M/I, mainland/island; Coll, collection (MNHN, Museum National d’Histoire Naturelle, Paris, France; JRM,
Johan R. Michaux); GENET, genetic clade (WEUR, western European; IBK, Italo-Balkanic; SIC, Sicily).

starting point was defined at the meeting point of the incisor
Outline analysis
and the bone at the upper edge of the mandible. For both the
The outline describes the overall shape of morphological mandible and the first upper molar (M1), we sampled
features. For molars, it describes the relative position and 64 points equally spaced along the outline.
swelling of the cusps. The outline of the bone in mandibles A radial Fourier transform (RFT) was applied to the M1
provides a good description of the processes involved in the outlines (Renaud, 1999; Renaud & Michaux, 2003). Using the
insertion of the masticatory muscles, as well as of the alveolar x,y-coordinates of the points, 64 radii (i.e. distance of each
region hosting the cheek teeth and the incisors. In both cases, point to the centre of gravity of the outline) were calculated.
outline analysis is an appropriate method to use to describe Using the RFT, the initial data set was described by the
subtle geographical changes in characters related to feeding variations of the radius as a function of the cumulative
(Renaud & Michaux, 2003; Renaud, 2005). distance along the outline. This function is approximated by a
The first upper molar was described by its two-dimensional finite sum of trigonometric functions of decreasing wave-
projection viewed from the occlusal surface. The starting point length, the harmonics. Each harmonic was weighted by two
was the maximum of curvature at the fore-part of the tooth. Fourier coefficients (FC), A n and B n . The zero harmonic A 0 is
The outline of the mandible describes the projection of the proportional to the size of each outline and was used to
hemi-mandible put flat on its side with the lingual side down. standardize all other the Fourier coefficients in order to
As the incisors can be free moving and the molars missing, eliminate isometric size effects and to concentrate on shape
only the outline of the mandibular bone was considered. The information only.

Journal of Biogeography 34, 339–355 341
ª 2006 The Authors. Journal compilation ª 2006 Blackwell Publishing Ltd