Asoriculus gibberodon (PETÉNYI, 1864)

Asoriculus gibberodon (PETÉNYI, 1864)

Pl. 6, Figs 1–5

Material. MN 15: Včeláre 2B: fragment of left md (ramus md), M1. Ivanovce: right md with p4–m3 (as Asoriculus gibberodon in Fejfar and Sabol 2005). MN 16: Javoříčko XI: complete left md except for the angular process. Javoříčko XVIII: right md without dentition. MN 17: Včeláre 6/1: fragment of right md without dentition. Koliňany 1: fragment of md without dentition (condylar process + part of corpus md preserved).

Description and comparison. Overall, our material corresponds to the original diagnosis of Asoriculus gibberodon (absence or reduction of pigment, robust jaws, low coronoid process, pronounced spiculum, shallow upper sigmoid notch, compression of the unicuspid dentition, short i1 with visible cingulum, compact m3 with shortened talonid).

We consider the significantly shorter distance between the condylar process and the ascending ramus (CdL) than in extant Neomys milleri to be an important diagnostic feature of Asoriculus gibberodon . Another notable difference is observed in the height of the condyle (Cd1Cd2), which is lower in our MN 15 – MN 17 material; it also possesses a narrower upper facet compared to N. milleri . The last lower molar is also often slenderer than in the extant species. Apart from metric characteristics, differences in non-metric traits were observed as well, such as closer position of the teeth row to the ascending ramus, prolonged beanshaped mandibular foramen (which is usually round and small in recent taxa) and strongly pronounced spiculum of the coronoid process in the Plio-Pleistocene form. The cingulum is, in agreement with the recent species, present on both labial and lingual side. In the specimen from Javoříčko XI, it is also present on the lower incisor (unfortunately this specimen is the only one in our collection that possesses the lower incisor), which represents another difference from N. milleri . A faint light orange tooth pigmentation is present in various amounts; in samples of MN 15–16 age it is completely absent.

The diagnosis (established at the description of Soriculus kubinyii KORMOS, 1934 ) emphasized “the bicuspid lower incisor with insignificant cusps and weak pigmentation limited to the apical part of the teeth”. Regarding the European fossil record, the following features are often mentioned: (i) the lower incisor is short and bicuspid ( Reumer 1984, Koufos et al. 2001, Rofes and Cuenca-Bescós 2006, Minwer-Barakat et al. 2010, Angelone et al. 2011, Vasileaidou et al. 2012, Rzebik-Kowalska 2013, Joniak et al. 2017, Moya-Costa et al. 2023) with (ii) a welldeveloped cingulum ( Reumer 1984, Dahlmann and Storch 1996, Furió and Angelone 2010, Minwer-Barakat et al. 2010, Rzebik-Kowalska 2013). (iii) Molars possess a rather weak cingulum ( Rofes and Cuenca-Bescós 2006, Botka and Mészáros 2017, Joniak et al. 2017), (iv) the entoconid is pronounced ( Rofes and Cuenca-Bescós 2006, Minwer-Barakat et al. 2010, Vasileaidou et al. 2012, Botka and Mészáros 2017). (v) Pigment is usually present only slightly, usually limited to tips of trigonid and talonid ( Reumer 1984, Popov 2003, Rofes and Cuenca-Bescós 2006, Botka and Mészáros 2017, Moya-Costa et al. 2023). (vi) The terminal part of the coronoid process is round ( Popov 2003, Rofes and Cuenca-Bescós 2006, Moya-Costa et al. 2023). (vii) The condylar process carries a wide but low upper facet of cylindrical shape, the lower facet is often bent lingually. The two facets are separated by long and extremely narrow interarticular area ( Rofes and Cuenca-Bescós 2006, Rzebik-Kowalska 2013, Moya-Costa et al. 2023). (viii) The horizontal ramus is low ( Rofes and Cuenca-Bescós 2006).

Compared to it, our material shows a high level of variability. It conforms to the above characters in a narrow upper facet (Včeláre 2B – MN 15, Včeláre 6/1 – MN 17, Včeláre 3 – MN 17, Včeláre 4E – Q 1), low horizontal ramus (Včeláre 6/1 – MN 17, Včeláre 3 – MN 17, Včeláre 3/1 – MN 17), narrow tip of coronoid process (Včeláre 6/1 – MN 17), significant entoconid (Ivanovce – MN 15, Javoříčko XI – MN 16, Včeláre 3/1 – MN 17, Včeláre 4/7 – Q 1), and absence or reduction of pigment (Ivanovce – MN 15, Javoříčko XI – MN 16, Včeláre 4/7 – Q 1). In contrast, some of our samples possess a high horizontal ramus (Ivanovce – MN 15), wide tip of coronoid process (Ivanovce – MN 15, Včeláre 3 – MN 17, Včeláre 4E – Q 1) or fuller pigmentation (Včeláre /upper molar/ – MN 15, Včeláre 3/1 – MN 17).