Neocricetodon magnus ( Fahlbusch, 1969 )

Colombero, Simone, Pavia, Giulio & Carnevale, Giorgio, 2014, Messinian rodents from Moncucco Torinese, NW Italy: palaeobiodiversity and biochronology, Geodiversitas 36 (3), pp. 421-475 : 427-431

Neocricetodon magnus ( Fahlbusch, 1969) ( Fig. 3 A-F)

Kowalskia magna Fahlbusch, 1969: 112 , pl. 9, fig. 6, pl. 10, figs 1, 2, pl.17, figs 1-6. — Pradel 1988: 252, pl. 9, figs 8-13.

Rotundomys (Kowalskia) magna – Janossy 1972: 34, pl. 2, figs 4, 5.

TYPE LOCALITY. — Podlesice, Poland.

REFERRED MATERIAL. — Two fragmented M1, two M3, four m1, seven m2, three m3. See further details in Appendix 1.

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

MEASUREMENTS. — Table 1.

DESCRIPTION

M1

The two available specimens are fragmented, lacking the posterior part. Anterocone split into two tubercles; the lingual anterolophule is present whereas the labial one is absent; in one specimen a low labial spur of the anterolophule develops in the anterosinus; anterior protoloph present; mesoloph partially preserved in one specimen in which is also visible a mesostyle.

M3

Labial anterolophule better developed than the lingual one; double protolophule; posterior part of the tooth strongly reduced: the posterior part is composed by a complex system of enamel crests and swellings in which hypocone and metacone are difficult to identify.

m1

A wide and stout anteroconid borders the entire anterior margin developing in sharp and flat ridges on the labial and lingual sides; in two specimens, a shallow incision in the distal side of the anteroconid wall is suggestive of an incomplete subdivision; anterolophulid double in three specimens and single and labial in one specimen; in two specimens the anterolophulids run parallel to each other whereas in the other one they are strongly divergent; mesolophid always present; well-developed and ending in a mesostylid.

m2

The lingual anterolophulid is strongly reduced; labial anterolophulid well-developed; well-developed mesolophid ending into a strong mesostylid.

m3

Large and triangular; anterolophulids well-developed both on the labial and lingual sides; well-developed mesolophid ending into a strong mesostylid.

REMARKS

The cricetine remains from MCC cannot be assigned to the genus Apocricetus Freudenthal, Mein & Martín-Suárez, 1998 because of the presence of strong mesolophs and mesolophids. The size of Pseudocricetus polgardiensis ( Freudenthal & Kordos, 1989) from the Late Miocene of Polgardi ( Hungary) is slightly smaller than that of Neocricetodon magnus from MCC even if the size ranges can partially overlap, while that of the sympatric Pseudocricetus kormosi (Schaub, 1930) is very similar ( Freudenthal & Kordos 1989; Freudenthal et al. 1998). The material from MCC differs from P. polgardiensis in having more developed mesolophs and mesolophids especially in the m2 and m3, as well as in the undivided anteroconid. P. kormosi differs from the specimens from MCC in the strong reduction of mesolophs and mesolophids, which are nearly absent in this species, and in the strong subdivision of the anteroconid in the m1s.

The studied material is characterized by the presence of long and strong mesolophs and mesolophids and unified or slightly subdivided anteroconid wall in the m1s. These features are distinctive of the Eurasian Neogene genera Neocricetodon Schaub, 1934 and Kowalskia Fahlbusch, 1969 (Daxner-Höck 1995; Daxner-Höck et al. 1996; Freudenthal et al. 1998). The taxonomic status of these two genera has been the subject of a complex discussion. Some authors ( Freudenthal et al. 1998) considered Kowalskia as a junior synonym of Neocricetodon , while others (Daxner-Höck et al. 1996) claimed that the material of the Late Miocene Neocricetodon grangeri (Young, 1927) , the type species of the genus Neocricetodon , is rather scarce and does not provide substantial evidence about the possible separation of Neocricetodon and Kowalskia , thus preferring to use the better defined Kowalskia . More recently, de Bruijn et al. (2012) examined some pictures of unpublished material assigned to N. grangeri and after comparisons with Kowalskia polonica Fahlbusch, 1969 , the type species of Kowalskia , considered this latter genus as a junior synonym of Neocricetodon (in agreement with Freudenthal et al. 1998). Following this opinion, Kowalskia is considered herein a junior synonym of Neocricetodon .

Large-sized species of the genus Neocricetodon , as that recognized at MCC, are relatively uncommon in the Neogene of Europe. Neocricetodon lavocati ( Hugueney & Mein, 1965) from the Late Miocene of Lissieu, Neocricetodon browni (Daxner- Höck, 1992) from Maramena (Miocene/Pliocene boundary of Greece) (Daxner-Höck 1992; 1995), the Late Miocene Neocricetodon nestori ( Engesser, 1989) from Baccinello V3 and Neocricetodon skofleki (Kordos, 1987) from Tardosbanya display a smaller size. Neocricetodon fahlbuschi ( Bachmayer &Wilson, 1970) from the Late Miocene of Austria (see also Freudenthal et al. 1998) is also smaller and only the size ranges of the M3 partially overlap with those of Neocricetodon from MCC. Direct comparisons with material referred to N. lavocati from Lissieu showed that it exhibits less developed mesolophids in the m3. From a morphological point of view, N. browni and N. nestori differ from the material of MCC in having a clearly subdivided anteroconid. N. skofleki differs from the material from MCC for a wider anterosinusid in the m2 and the presence of a double anteroloph in the M1. With respect to N. fahlbuschi , the studied material differs mainly in the strong reduction of the M3, less divided anterocones in M1 and the presence of a broader, stouter and almost undivided anteroconid in the m1s. Other slight differences include the presence of a double anterolophule, and the frequent absence of the anterior protoloph in the M1 of N. fahlbuschi and the overall better developed mesoloph(id)s of the molars from MCC in which they always reach the dental margins.

Neocricetodon seseae Aguilar, Calvet & Michaux, 1995 from the Late Miocene localities of Castelnou 1, Crevillente 14 and 22, Cucuron and Lissieu (see Freudenthal et al. 1998), even if slightly smaller, approaches the size of the cricetine material from MCC. However, this species shows some unique features, including the less developed mesolophids, the higher degree of subdivision of the anteroconid and the almost unreduced M3.

Neocricetodon polonicus ( Fahlbusch, 1969) known from some Pliocene localities of Central Europe ( Fahlbusch 1969; Pradel 1988) and Neocricetodon intermedius ( Fejfar, 1970) from the Pliocene of Ivanovce and Vue-des-Alpes ( Bolliger et al. 1993) have rather smaller molars, even though they display very similar morphological characters (e.g., long and strong mesolophids and mesolophs, and undivided, wide and stout anteroconid). The size of Neocricetodon magnus Fahlbusch, 1969 from the type locality of Podlesice ( Fahlbusch 1969; Pradel 1988) and Osztramos 1 ( Janossy 1972) fit very well with that of the specimens from MCC except for the length of M3, which is highly variable in the material from Podlesice. Moreover, the morphological features of N. magnus are consistent with those of the material from MCC, especially as far as concerns the long and strong mesolophids and mesolophs, the unified or slightly subdivided anteroconids in the m1s, and the reduction of the anterosinusids of the m2. Two M3 from Podlesice, MF/823/16 figured in Fahlbusch (1969: taf. XVI/5) and MF/1684 figured in Pradel (1988: pl. IX/10) display a strong reduction of the posterior part being remarkably similar to the M3 from MCC. However, some details are slightly different; one of four available m1 from MCC has a single anterolophulid, while a double anterolophulid generally occurs in N. magnus from Podlesice; the measurements of the M3 from Podlesice display a higher variability even if this is probably due to the scarce sample of MCC (two M3) These differences should not be regarded as significant considering the nearly unknown intraspecific variability of N. magnus . Moreover, a detailed morphological description of the dental elements was exclusively provided for the scarce material analyzed by Fahlbusch (1969), and very little is known about the morphological features of the Osztramos 1 assemblage.

In summary, the only known species of the genus Neocricetodon exhibiting a large size, well-developed mesolophids and mesolophs, broad, wall-like, undivided anteroconids, and reduction of the posterior portion of the M3 is Neocricetodon magnus . The few morphological differences, such as the presence of a single labial branch of the anterolophulid in one (of the four available) m1 can be related to the slightly older age of the material from MCC, even considering that this feature is more common in some Miocene species such as N.fahlbuschi ( Bachmayer & Wilson 1970) .

To date, N. magnus has been exclusively reported from the Pliocene deposits of Central Europe. The material from MCC indicates that this large cricetine was present at least at the end of the Messinian in southern Europe. This is the second record of the genus Neocricetodon in the Italian Peninsula, the first one being that of N. nestori in the slightly older locality of Baccinello V3 ( Engesser 1989; Rook et al. 2011). The two species do not appear to be closely related ( Engesser 1989).

According to Daxner-Höck (1995), N. magnus is in some ways related to N. schaubi (MN11), N. skofleki (MN11-MN12), N. browni (MN13), N. polonicus (MN14), and N. intermedia (MN15). However, as already pointed out by Fahlbusch (1969) and Fejfar (1970), the closest relatives of N. magnus should be N. polonicus and N. intermedius with which it shares a very similar morphology, mostly differing in its larger size.

Figures

FIG. 3. — Isolated teeth of Neocricetodon magnus (Fahlbusch, 1969) from Moncucco Torinese. A, MGPT-PU127498, M1 dex (fragmented); B, MGPT-PU127500, M3 dex.; C, MGPT-PU127424, m1 sin.; D, MGPT-PU127932, m1 sin.; E, MGPT-PU127427, m2 sin.; F, MGPT-PU127423, m3 sin. Scale bar: 1 mm.