# Odontometric divergence in Savi's vole Umbrian populations Microtus savii (de Sélys-Longchamps, 1838) (Arvicolinae, Rodentia)

Patrick Brunet-Lecomte, Angela Gaggi, Giuseppina Lombardi, Luca Convito, Andrea Maria Paci

<figure><img src="image_1.png" /></figure>

## To cite this version:

Patrick Brunet-Lecomte, Angela Gaggi, Giuseppina Lombardi, Luca Convito, Andrea Maria Paci. Odontometric divergence in Savi's vole Umbrian populations Microtus savii (de Sélys-Longchamps, 1838) (Arvicolinae, Rodentia). Carnets Natures, 2024, 11, pp.93-98. hal-04889923

HAL Id: hal-04889923

https://hal.science/hal-04889923v1

Submitted on 15 Jan 2025

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Odontometric divergence in Savi's vole Umbrian populations *Microtus savii* (de Sélys-Longchamps, 1838) (Arvicolinae, Rodentia)

Patrick Brunet-Lecomte<fnref n="1" />*, Angela Gaggi<fnref n="2" />, Giuseppina Lombardi<fnref n="3" />, Luca Convito<fnref n="3" />, Andrea Maria Paci<fnref n="4" />

## Abstract

This study highlights the odontometric divergence on the first lower molar ($M_1$) criteria in five Umbrian *Microtus savii* populations. Poggiovalle and Forcatura, the two most geographically and climatically distant populations, differ in all the criteria studied. A west-east decrease of 0.126 mm is observed between the populations of Poggiovalle and Forcatura. The Poggiovalle population differs from the other populations by a lower length/width ratio $M_1$, and the Forcatura population reports an $M_1$ anterior part (51.62%) higher than the Borgo Trevi population (50.65%).

**Keywords:** *Microtus savii*, Arvicolinae, Rodentia, Umbria, Odontometry.

## Divergence odontométrique chez les populations ombriennes du campagnol de Savi *Microtus savii*
(de Sélys-Longchamps, 1838) (Arvicolinae, Rodentia)

### Résumé

Cette étude met en évidence la divergence odontométrique sur les critères de la première molaire inférieure ($M_1$) dans cinq populations ombriennes de *Microtus savii*. Poggiovalle et Forcatura, les deux populations les plus éloignées géographiquement et climatiquement, diffèrent sur tous les critères étudiés. Une diminution ouest-est de 0,126 mm est observée entre les populations de Poggiovalle et Forcatura. La population de Poggiovalle se distingue des autres populations par un rapport longueur/largeur $M_1$ plus faible, et la population Forcatura présente une partie antérieure de la $M_1$ (51,62 %) plus élevée que la population de Borgo Trevi (50,65 %).

**Mots clés:** *Microtus savii*, Arvicolinae, Rodentia, Ombrie, Odontométrie.

## Divergenza odontometrica nelle popolazioni umbre di Arvicola di Savi *Microtus savii*
(de Sélys-Longchamps, 1838) (Arvicolinae, Rodentia)

### Riassunto

Il presente studio evidenzia la divergenza odontometrica riguardo a criteri nel primo molare inferiore ($M_1$) in cinque popolazioni umbre di *Microtus savii*. Poggiovalle e Forcatura, le due popolazioni più distanti dal punto di vista geografico e climatico, differiscono per tutti i criteri studiati: un decremento ovest-est di 0,126 mm viene osservato, rispettivamente, tra queste due popolazioni. La popolazione di Poggiovalle si differenzia dalle altre popolazioni per il rapporto lunghezza/larghezza di $M_1$ più basso, mentre la popolazione di Forcatura presenta la parte anteriore di $M_1$ più alta (51,62%) rispetto alla popolazione di Borgo Trevi (50,65%).

**Parole chiave:** *Microtus savii*, Arvicolinae, Rodentia, Umbria, Odontometria.

<figure><img src="image_3.png" /></figure>

<footnote n="1">1. 5, Rue de Palanka – 38000 Grenoble, France, patrick.brunet-lecomte@wanadoo.fr</footnote>

<footnote n="2">2. Liceo Statale "Plinio Il Giovane", 06012 Città di Castello, PG, Italy, angela.gaggi@virgilio.it</footnote>

<footnote n="3">3. Osservatorio Faunistico Regionale, Regione Umbria, Perugia, Italy, glombardi@regione.umbria.it, lconvito@regione.umbria.it</footnote>

<footnote n="4">4. via dell'Antico Forno, 2 – 06012 Città di Castello (PG), Italy, ampaci61@gmail.com</footnote>
**Introduction**

The Savi's vole was described by Sélys-Longchamps (1838) under the name *Arvicola savii* from specimens collected by P. Savi in the region of Pisa (Tuscany, Italy). The systematic and taxonomic status of the Savi's vole has changed several times since its description in 1838 (Trouessart, 1910; Miller, 1912; Ellermann & Morrison-Scott, 1951; Niethammer & Krapp, 1982), and it is currently classified in the subgenus *Microtus* (*Terricola*) (Chaline *et al.*, 1988; Wilson & Reeder, 2005; Pardiñas *et al.*, 2017; Krystufek & Shenbrot, 2022).

The current geographical distribution of *M. savii* includes northern and central Italy, Ticino (southern Switzerland) and the eastern edge of the Alpes-Maritimes département (France) (Amori *et al.* 2008). In southern and central Italy, *M. savii* is replaced by *M. brachycercus*, described from Calabria by von Lehmann (1961), initially considered a subspecies and now a valid species (Galleni *et al.*, 1994, 1998; Wilson & Reeder, 2005; Bezerra *et al.*, 2015; Loy *et al.*, 2019; Krystufek & Shenbrot, 2022). However, the distribution of the two species in central Italy remains to be clarified.

In Umbria, *M. savii* occupies almost the entire region. The species has been found in 54 municipalities, with a regional distribution index of 0.33 and a municipal distribution index of 0.59 (Gaggi & Paci, 2014); it has been reported from 65 m of the Penna in Teverina (TR) (Gaggi & Paci, op.cit.) over 1800 m asl near Forca Viola (Parco Nazionale dei Monti Sibillini, PG-AP) (Nappi *et al.*, 2017).

Previous odontometric analyses of the first lower molar ($M_1$) criteria (Nappi *et al.* 2006, 2019) have highlighted significant divergences between *M. savii* and *M. brachycercus* and within *M. savii* populations; in particular, southern populations have a less developed anterior part of the $M_1$ and a more open anterior loop than central and northern Italian populations.

Genetic analyses carried out on Umbrian populations by Lucentini *et al.* (2023) confirmed the populations attribution to *M. savii*, showing peculiar genetic polymorphisms that could be due either to the wide sampling area represented by the owls' hunting grounds, or the recent evolutionary history of the populations analysed.

<figure><img src="image_4.png" /><figcaption>**Fig. 1** - Geographical localisation of *Microtus savii* populations.</figcaption></figure>

Main populations: 1-Forcatura (Foligno, province of Perugia), 2-Borgo Trevi (Trevi, province of Perugia), 3-Madonna della Stella (Montefalco, province of Perugia), 4-Scalocchio (Città di Castello, province of Perugia) and 5-Poggiovalle (Fabro, province of Terni).

Secondary populations: 6-Sigillo (province of Perugia), 7-Montemezzo (Valfabbrica, province of Perugia), 8-Ansa degli Ornari (Perugia, province of Perugia) and 9-Case Cola (Parrano, province of Terni).
The inclusion of new populations allows to improve
the knowledge of the odontometric variation of this
species at the Umbrian scale and to propose new
multidisciplinary studies.

**Material and method**

The material studied came from (Fig. 1):

a) five main populations: 1-Forcatura (Foligno, province of Perugia) N=176 M₁, 2-Borgo Trevi (Trevi, province of Perugia) N=81 M₁, 3-Madonna della Stella (Montefalco, province of Perugia) N=150 M₁, 4-Scalocchio (Città di Castello, province of Perugia) N=116 M₁ and 5-Poggiovalle (Fabro, province of Terni) N=362 M₁;

b) four secondary populations: 6-Sigillo (province of Perugia) N=30 M₁, 7-Montemezzo (Valfabbrica, province of Perugia) N=17 M₁, 8-Ansa degli Ornari (Perugia, province of Perugia) N=18 M₁ and 9-Case Cola (Parrano, province of Terni) N=20 M₁.

According to Orsomando *et al*. (1999), the localities
studied are characterised by the following bioclimatic
schemes: Poggiovalle: submediterranean hills,
temperate variant; Scalocchio: high hills, humid variant;
Madonna della Stella: low-hills; Borgo Trevi: low-hills,
humid variant; Forcatura: low-mountain, humid variant;
Case Cola: low-hills; Sigillo: high-hills, humid variant;
Valfabbrica: high-hills; Ansa degli Ornari: low-hills.

Descriptive analysis was performed on main and
secondary populations, and comparative analysis was
performed on the main populations only (insufficient
sample size for statistical comparison in secondary
populations).

Comparative analysis was performed using the following M1 criteria (Brunet-Lecomte, 1990; Brunet-Lecomte *et al.*, 2010) (Fig. 2): total length = measure 6, anterior part = (measure 6-measure 3)/measure 6 x 100, closure of anterior loop = (measure 20-measure 18)/measure 21 x 100 and length/width ratio = measure 6/measure 21.

Results

The results of the descriptive and statistical analyses
are shown in **Tabl. 1** and **Fig. 3**.

**Discussion and conclusion**

Poggiovalle and Forcatura, the most geographically
and climatically distant populations, differ on all criteria.
For the total length, a west-east decrease of 0.126 mm
is observed between the populations of Poggiovalle
(2.695 mm) and Forcatura (2.569 mm). Furthermore,
the population of Poggiovalle differs from the other
populations by a lower length/width ratio M₁. The
population of Poggiovalle also differs from the
population of Forcatura by a less developed anterior
part.

<figure><img src="image_5.png" /><figcaption>**Fig. 2** - Morphometry of the first lower molar of *Microtus* (*Terricola*) *species*. Six measures taken (in mm), labelled 3, 4, 6, 18, 20 and 21.</figcaption></figure>

The main populations were compared using one-way analysis of variance (ANOVA). In the event of a significant population effect, the analysis was supplemented by a multiple Bonferroni comparisons test to determine precisely between which populations a significant difference was observed.
<table><caption>Tabl. 1 - Description of first lower molar criteria in Umbrian *Microtus savii* populations.</caption><thead><tr><th>Criteria</th><th>Total length (mm)</th><th>Anterior part (%)</th><th>Anterior loop (%)</th><th>Length/width (ratio)</th></tr></thead><tbody><tr><td>ANOVA</td><td>p&lt;0.0001</td><td>p&lt;0.0001</td><td>p&lt;0.0001</td><td>p&lt;0.0001</td></tr><tr><th>Population</th><th>N</th><th colspan="3">Mean±Standard deviation<br>Bonferroni test : Means with same letter are not significantly different<br>(p≥0.05)</th></tr><tr><td>Forcatura</td><td>176</td><td>2.569±0.124<br>C</td><td>51.62±1.39<br>C</td><td>26.30±6.32<br>A</td><td>2.701±0.138<br>B</td></tr><tr><td>Borgo Trevi</td><td>81</td><td>2.600±0.096<br>B C</td><td>50.65±1.33<br>A</td><td>26.82±7.63<br>A</td><td>2.713±0.135<br>B</td></tr><tr><td>Madonna della Stella</td><td>150</td><td>2.604±0.096<br>C</td><td>51.20±1.21<br>B</td><td>25.03±7.59<br>A B</td><td>2.734±0.125<br>B</td></tr><tr><td>Scalocchio</td><td>116</td><td>2.649±0.122<br>B</td><td>51.13±1.19<br>A B</td><td>22.53±7.32<br>C</td><td>2.714±0.132<br>B</td></tr><tr><td>Poggiovalle</td><td>362</td><td>2.695±0.141<br>A</td><td>50.74±1.31<br>A</td><td>24.26±6.42<br>B C</td><td>2.658±0.139<br>A</td></tr><tr><th></th><th></th><th colspan="3">Mean±Standard deviation (no comparison performed)</th></tr><tr><td>Sigillo</td><td>30</td><td>2.599±0.102</td><td>50.653±1.452</td><td>25.439±7.505</td><td>2.708±0.116</td></tr><tr><td>Montemezzo</td><td>17</td><td>2.619±0.136</td><td>51.237±1.457</td><td>17.217±8.076</td><td>2.698±0.107</td></tr><tr><td>Ansa degli Ornari</td><td>18</td><td>2.705±0.109</td><td>50.923±1.404</td><td>20.859±5.356</td><td>2.773±0.146</td></tr><tr><td>Case Cola</td><td>20</td><td>2.752±0.127</td><td>50.883±1.090</td><td>27.098±6.220</td><td>2.691±0.163</td></tr></tbody></table>

ANOVAs showed that the populations were significantly different (p<0.0001) for all criteria. Significant differences between *M. savii* populations according to the Bonferroni test were as follows:

1) the total length is greater in the Poggiovalle population (2.695±0.141 mm) than in the Scalocchio, Madonna della Stella, Borgo Trevi and Forcatura populations (2.649±0.122 mm, 2.604±0.096 mm, 2.600±0.096 mm and 2.569±0.124 mm, respectively);

2) the anterior part is less in the Borgo Trevi and Poggiovalle populations (50.65% and 50.74±1.31%, respectively) than in the Madonna della Stella and Forcatura populations (51.20±1.21% and 51.62±1.39%, respectively);

3) the anterior loop is more open in the Borgo Trevi and Forcatura populations (26.82±7.63% and 26.30±6.32%, respectively) than in the Poggiovalle and Scalocchio populations (24.26±6.42% and 22.53±7.32%, respectively);

4) the length/width ratio is lower in the Poggiovalle population (2.658±0.139) than in the Forcatura, Borgo Trevi, Scalocchio and Madonna della Stella populations (2.701±0.138, 2.713±0.135, 2.714±0.132 and 2.734±0.125, respectively).

The population of Scalocchio differs from the other populations of the province of Perugia (Madonna della Stella, Borgo Trevi and Forcatura) by a more closed anterior loop.

Compared to the means found in central Italy by Nappi *et al.* (2019), the population of Poggiovalle is characterised by a greater total length (2.695 versus 2.552 mm), while that of Forcatura is similar (2.569 mm).

The populations of Forcatura, Madonna della Stella and Borgo Trevi are close, except for the anterior part, especially between Forcatura and Borgo Trevi, for which a difference of 0.97% (51.62% - 50.65%) is found. The anterior part of the population of Borgo Trevi is smaller than that reported for central Italy by Nappi *et al.* (2019) (51.33%).

For populations with sample sizes estimated to be insufficient for relevant statistical analysis, the following should be noted:

The population of Case Cola (N=20), near Poggiovalle, has a high total length (2.752±0.127 mm), as in

Poggiovalle, while the length/width ratio of $M_1$ is lower (2.691±0.163 mm), similar to those observed in the populations of the province of Perugia;

In the population of Sigillo (N=30), the anterior part of the $M_1$ (50.65%) is closer to that of Borgo Trevi (more distant) than to that of Scalocchio (less distant);

The population of Montemezzo (N=17) has a close anterior loop (17.22±8.08%) and Ansa degli Ornari (N=18) is characterised by a large total length (2.705±0.109 mm).

None of the 3 populations with a high $M_1$ length (Poggiovalle, Case Cola and Ansa degli Ornari) has a humid bioclimatic scheme. Among the populations with a humid bioclimatic scheme (Scalocchio, Borgo Trevi, Forcatura and Sigillo), the development of the anterior part is moderate (Borgo Trevi and Sigillo) or medium (Scalocchio and Forcatura) and the closure of the anterior loop is medium (Scalocchio) or moderate (Borgo Trevi, Forcatura and Sigillo).
<figure><img src="image_6.png" /><figcaption>**Fig. 3** - Mean±2*SEM of first lower molar criteria in Umbrian *Microtus savii* populations. N: sample size. SEM: standard error of the mean, SEM = standard deviation / square root (N).</figcaption></figure>

The results obtained show the interest of a genetic study, focused in particular on the Poggiovalle and Forcatura populations, as already carried out by Lucentini *et al*. (2023) on the Madonna della Stella population.

**Acknowledgements:** Luca Fabbriccini kindly supplied the pellets of Long-eared Owl *Asio otus* from the Forcatura site.

## References

Amori G., Contoli L. & Nappi A. (2008) - *Mammalia*
*II. Erinaceomorpha, Soricomorpha, Lagomorpha,
Rodentia*. In “Fauna d’Italia” Series; Edizioni
Calderini: Milano (Italy), XLIV. 736 p.

Bezerra A.M.R., Annesi F., Aloise G., Amori G., Giustini L. & Castiglia R. (2015) - Integrative taxonomy of the Italian pine voles, *Microtus savii* group (Cricetidae, Arvicolinae). *Zool. Scr*, 45: 225-236.

Brunet-Lecomte P. (1990) - Évolution morphologique de la première molaire inférieure des campagnols souterrains d'Europe (Arvicolidae, Rodentia). *Z. Säugetierkunde*, 55: 371-382.

Brunet-Lecomte P., Nappi A. & Montuire S. (2010) - Comparative odontometrical analysis of the first lower molar in *Microtus* (*Terricola*) *multiplex* (Arvicolinae, Rodentia) from Western Alps. *Acta Theriologica*, 55 (2): 129-138.

Chaline J., Brunet-Lecomte P. & Graf J.-D. (1988) - Validation de *Terricola* Fatio 1867 pour les Campagnols souterrains (Arvicolidae, Rodentia) paléarctiques actuels et fossiles. *C. R. Acad. Sci. Paris*, 306 Série III: 475-478.

Ellermann J. R. & Morrison-Scott, T. C. S. (1951) - *Checklist of Paleartic and Indian mammals*, 1758 to 1946. British Museum (Natural History), London (UK). 810 p.

Gaggi A. & Paci A.M. (2014) - *Atlante degli Erinaceomorfi, dei Soricomorfi e dei piccoli Roditori dell'Umbria*. Regione Umbria, Perugia (Italy). 211 p.

Galleni L., Stanyon R., Tellini A., Giordano G. & Santini L. (1994) - Taxonomy of *Microtus savii* (Rodentia, Arvicolidae) in Italy: Cytogenetic and hybridization data. *J. Mammal*, 75: 1040-1044.

Galleni L., Stanyon R., Contadini L. & Tellini A. (1998)
- Biogeographical and kariological data of the *Microtus savii* group (Rodentia, Arvicolidae) in Italy. *Bonn. Zool. Beitr.*, 47: 277-282.

Krystufek B. & Shenbrot G. L. (2022) - *Voles and lemmings (Arvicolinae) of the Palaearctic Region.* University of Maribor press, Maribor (Slovenia). 436 p.

Lehmann E. (von). (1961) - Über die Kleinsäuger der La Sila (Kalabrien). *Zool Anz.*, 167: 213-229.

Loy A., Aloise G., Ancillotto L., Angelici F.M., Bertolino S., Capizzi D., Castiglia R., Colangelo P., Contoli L. & Cozzi B. (2019) - Mammals of Italy: An annotated checklist. *Hystrix*, 30: 87-106.

Lucentini L., Brunet-Lecomte P., Brustenga L., La Porta G., Barili A., Gaggi A., Gentili S., Nappi A. & Paci A. M. (2023) - Long Eared Owls (*Asio otus Linnaeus, 1758) as Field-Assistants in an Integrative Taxonomy Survey of a Peculiar *Microtus savii* (Rodentia, Cricetidae) Population. *Applied Sciences* 13, 4703: 1-14.

Miller G. S. (1912) - Catalogue of the mammals of Western Europe (Europe exclusive of Russia) in the collection of the British Museum. London (UK). 1019 p.

Nappi A., Brunet-Lecomte P. & Montuire S. (2006) - Intraspecific morphological tooth variability and geographical distribution: Application to the Savi's vole, *Microtus (Terricola) savii* (Rodentia, Arvicolinae). *J. Nat. Hist.*, 40: 345-358.

Nappi A., Brunet-Lecomte, P. & Montuire, S. (2019) - The systematics of *Microtus* (*Terricola*) savii group: An odonthometrical perspective (Mammalia, Rodentia, Cricetidae). *J. Nat. Hist.*, 53: 2855-2867.

Nappi A., Paci A.M., Fusari M., Gaggi A., Fiacchini D., Romano C., Castiglia R., Annesi F., Amori G., Mosci P. & Ricci G. (2017) - The snow vole *Chionomys nivalis* (Martins, 1842) (Mammalia, Rodentia, Cricetidae) on the Sibillini Mountains (Central Italy). *Rend. Fis. Acc. Lincei* DOI 10.1007/s12210-017-0644-9, Published online 23 September 2017: 1-6.

Niethammer J. & Krapp F. (1982) - *Handbuch der Säugetiere Europas. Akademische Verlagsgessellschaft*. Wiesbaden (Germany). 649 p.

Orsomando E., Catorci A., Pitzalis M. & Raponi M., (1999) - *Carta fitoclimatica dell'Umbria, Scala 1:200.000*. Regione dell'Umbria, Università di Camerino, S.E.L.C.A., Firenze. 58 p.

Pardiñas M.F.J., Myers P., León-Paniagua L., Garza N.O., Cook J.A., Kryštufek B., Haslauer R., Bradley R.D., Shenbrot G.I. & Patton J.L. (2017) - *Family Cricetidae (true Hamsters, Voles, Lemmings and New World Rats and Mice)*. In Handbook of the Mammals of the World Vol. 7. Rodents II; Wilson, D.E., Lacher, T.E., Jr., Mittermeier, R.A., Eds.; Lynx Edicions: Barcelona (Spain). 1008 p.

Sélys-Longchamps E. (de) (1838) - Nouvelles espèces de mammifères du genre Campagnol. *Rev Zool.*, 248-249.

Trouessart E.-L. (1910) - *Faune des Mammifères d'Europe*. Berlin: R. Friedländer & Sohn, Berlin (Germany). 266 p.

Wilson D., Reeder D. M., eds. (2005) - *Mammal species of the world. A taxonomic and geographic reference.* 3rd edition. Johns Hopkins University Press, Baltimore (USA). 2142 p.

DOAJ

DIRECTORY OF
OPEN ACCESS
JOURNALS

<figure><img src="image_7.png" /></figure>

Soumis le 22 octobre 2024

Accepté le 25 novembre 2024

Publié en ligne (pdf) le 29 novembre 2024