Apodemus gudrunae van de Weerd, 1976

Colombero, Simone, Pavia, Giulio & Carnevale, Giorgio, 2014, Messinian rodents from Moncucco Torinese, NW Italy: palaeobiodiversity and biochronology, Geodiversitas 36 (3), pp. 421-475 : 441-442

Apodemus gudrunae van de Weerd, 1976 ( Fig. 5 A-F)

Apodemus gudrunae van de Weerd, 1976: 84 , pl. 3, figs 1-6. — Adrover et al. 1993a: 68, pl. 8, figs 4-9. — Sarica-Filoreau 2002: 19, figs 4, 5. — Minwer-Barakat et al. 2009b: 855, fig. 3. — Colombero et al. 2013: 118, fig. 4G, H, P, Q.

Apodemus cf. gudrunae – De Giuli 1989: 208, pl. 3, figs 13-20. — Abbazzi et al. 2008: 622, fig. 6D.

TYPE LOCALITY. — Valdecebro 3, Spain.

REFERRED MATERIAL. — Two maxillary fragments bearing M1 and M2; 68 isolated M1; 52 isolated M2; 20 isolated M3; 63 isolated m1; 35 isolated m2; 20 isolated m3. See Appendix 1 for further details.

OCCURRENCE IN THE STUDIED LAYERS. — MCC3, MCC4, MCC5, MCC7.

MEASUREMENTS. — see Table 6.

DESCRIPTION

M1

t1 smaller than t2; the t3 exhibits a short posterior spur not reaching the t5; t4-t7 connection generally low or rarely absent; t7 absent in two specimens, narrow or crest-like in 20% of specimens and welldeveloped in the others; t12 well developed.

M2

t6-t9 connection absent in 15% of specimens and low in the others; t7 generally narrow or crest-like; t4-t7 connection absent in 30% of the specimens and low in the others; t12 absent in 15% of specimens.

M3

t3 absent in 30% of specimens and very small in the rest; t8-t9 complex bilobed or elliptic, connected to the t6, and, more rarely, to the t4.

m1 tma always present and well developed; protoconidmetaconid complex connected with anteroconid complex through low connections mainly developed on the lingual side; hypoconid-entoconid complex isolated from the protoconid-metaconid complex; the c1 is well-developed; labial cingulum bearing two (50% of specimens); three (35% of specimens) or four (15% of specimens) cusplets.

m2

Anterolabial cuspid well developed; hypoconidentoconid complex isolated from the protoconid-metaconid complexc1 well-developed; labial cingulum with one or two cusplets.

m3

Small anterolabaial cuspid formed by an enamel swelling; posterior complex rounded isolated; a small accessory cusplet can occur on the labial side.

REMARKS

The size of the large-sized species of Apodemus Kaup, 1829 from MCC are very similar to those of Apodemus gudrunae van de Weerd, 1976 from many Late Miocene localities of Europe such as the type locality Valdecebro 3 ( van de Weerd 1976), Masada del Valle 7, La Fontana, Arquillo 1 ( van de Weerd 1976; Adrover et al. 1993a), Negratín 1(Minwer- Barakat et al. 2009b), Verduno (Colombero et al. 2013), and Asmasya (southwestern Anatolia, Sarica-Filoreau 2002). The described material from MCC is somewhat larger than that referred to A. cf. gudrunae from Pino Mojón and Barranco de Cañuelas ( Sesé 1989) and slightly smaller than that of A. cf. gudrunae from Castelnou 3 ( Aguilar et al. 1991). From a morphological point of view, the assemblage of A. gudrunae from MCC is very similar to that of the type locality of Valdecebro 3 except for some M1 that display a slightly more developed t7.

With respect to Apodemus gorafensis Ruiz Bustos, Sesé, Dabrio, Peña & Padial, 1984 , reported in Europe since the latest Miocene and widely distributed during the Pliocene, the size of the teeth from MCC is smaller. Nevertheless, the measurements of A. gorafensis from Tomea Eksi 1 and 2 ( Hordijk & de Bruijn 2009) largely overlap those of the material from MCC. According to Sarica-Filoreau (2002), the main morphological difference between A. gudrunae and A. gorafensis is the development of the t1 of the M1. This tubercle is larger and stout in A. gorafensis than in A. gudrunae . Moreover, the larger size of the t1 produces a deep inflexion between t1 and t2 on the lingual side of the M1 of A. gorafensis . The t1 of the specimens from MCC is rather small and the inflexion is shallow. Moreover, compared with A. gorafensis from the type locality of Gorafe A, the specimens of Apodemus from MCC exhibit a slightly smaller t7 and less developed posterior spurs on t3. For these reasons, the material from MCC is referred to as A. gudrunae .

The size of Apodemus atavus Heller, 1936 , present in Europe since the latest Miocene and abundant in the Pliocene and the Pleistocene, is generally smaller than that of A. gudrunae . Moreover, in A. atavus the t7 is more frequently isolated and the t3 produces longer posterior spurs than in A. gudrunae . Some M1 of A. gudrunae from MCC exhibit an isolated t1. This morphological feature is relatively common among the species of the genus Rhagapodemus Kretzoi, 1959 , widespread in Europe from the Late Miocene to the Pleistocene. Most of them, especially the Plio-Pleistocene species, namely Rhagapodemus hautimagnensis Mein & Michaux, 1970 , R. frequens Kretzoi, 1959 , R. ballesioi Mein & Michaux, 1970 and R. vandeweerdi de Bruijn & van der Meulen, 1975 can be easily differentiated by the higher-crowned teeth. Moreover, in the M1 of Rhagapodemus , the t1 is always isolated and the t3 is more anteriorly placed, being very close to the t2. However, some specimens of Rhagapodemus primaevus ( Hugueney & Mein, 1965) from the Late Miocene of Lissieu are similar to A. gudrunae especially in the low-crowned teeth and the shape and position of t3. Anyway, these two species exhibit some differences. In particular, the tubercles of the upper molars of R. primaevus are clearly vertical especially as regards the t1, whereas the tubercles of the lingual and labial sides of A. gudrunae are slightly inclined internally towards the longitudinal axis of the tooth. A. gudrunae is a common member of the MN13 vertebrate assemblages of the Mediterranean area, being regularly reported in a number of latest Miocene localities of Spain, France, Italy, Greece and Turkey (see NOW Database, Fortelius 2012).

Figures

FIG. 5. — Isolated teeth of Apodemus Kaup, 1829 from Moncucco Torinese:A-F, Apodemus gudrunae van de Weerd,1976; A, MGPT- PU127084, M1 dex.; B, MGPT-PU127731, M2 sin.; C, 127661, M3 dex.; D, MGPT-PU127974, m1 sin.; E, MGPT-PU127475,m2 dex.; F, MGPT-PU127665, m3 sin.; G-L, Apodemus atavus Heller, 1936 from Moncucco Torinese; G, MGPT-PU127659, M1 dex.; H, MGPT- PU127660, M2 sin.; I, MGPT-PU127661, M3 sin.; J, MGPT-PU127180, m1 sin.; K, MGPT-PU127662, m2 sin.; L, MGPT-PU127663, m3 dex. Scale bar: 1 mm.