Rzebikia skoczeni ( Zijlstra, 2010 ) Sansalone & Kotsakis & Piras, 2016

Sansalone, Gabriele, Kotsakis, Tassos & Piras, Paolo, 2016, New systematic insights about Plio-Pleistocene moles from Poland, Acta Palaeontologica Polonica 61 (1), pp. 221-229 : 224-225

Rzebikia skoczeni ( Zijlstra, 2010) comb. nov.

1993 Neurotrichus minor Skoczeń ; Skoczeń 1993: 130–133, fig. 4. 1994 Neurotrichus minor Skoczeń ; Rzebik-Kowalska 1994: 80, 88. 2004 Quyania minor (Skoczeń) ; Popov 2004: 75.

2005 Neurotrichus minor Skoczeń ; Rzebik-Kowalska 2005: 127. 2009 Neurotrichus minor Skoczeń ; Rzebik-Kowalska 2009: 9, 21. 2010 Neurotrichus skoczeni ; Zijlstra 2010: 1903.

2014? Neurotrichus skoczeni Zijlstra ; Rzebik-Kowalska 2014: 11–12. Etymology: In honor of Stanisław Skoczeń, who originally described this species.

Type material: Holotype: right humerus ZPAL /M-2/2 ( Skoczeń 1993: fig. 4) . Paratype: isolated left M1 ( ZPAL /M-2/1) .

Type locality: Węże 2, Poland .

Type horizon: Ruscinian–Villanyian boundary (MN 15, MN 16).

Emended diagnosis.—Small sized shrew-mole with moderate digging adaptation. The humerus have a well developed scalopine ridge and partially unfused bicipital tunnel, the pectoral tubercle is laterally displaced. The cingula of the M1 weaker and reduced.

Description.—See Skoczeń (1993) for a complete and detailed description of the material. See SOM 2 for linear measurements of the material.

Remarks.—The humerus is very similar to that of Rzebikia polonica , it differs only for its smaller size and the laterally displaced pectoral tubercle. The M1 is longer and narrower relative to that of Rzebikia polonica and differs for the shorter protoconus lacking a cingulum, the paraconus is narrower, the proto- and metaconuli are less prominent and the precingulum is markedly weak and short.

This species has been previously described as Neurotrichus minor by Skoczeń (1993). Although we changed the generic attribution for this species we maintained the specific attribution of skoczeni because the name minor is a primary homonym and permanently invalid (ICZN 1999: art. 57.2; Zijlstra 2010).

The following differential diagnoses are based on Rzebikia polonica because of the high similarity with the smaller species Rzebikia skoczeni and because of the most abundant material available for comparison.

Neurotrichus gibbsii : Rzebikia polonica shows many similarities in particular for the teeth (see Skoczeń 1980 for a detailed description) with the North American shrew mole, but differs by having reduced precingulids in m1. It is distinct from Neurotrichus gibbsii in the morphology of the humerus which is clearly less adapted to fossoriality by having: (i) a partially unfused bicipital tunnel, (ii) a more conspicuous scalopine ridge, (iii) a shorter teres tubercle, (iv) a longer greater sulcus, (v) the lesser tuberosity is less expanded in proximal direction.

Urotrichus talpoides : Rzebikia polonica is different in many features from the Japanese greater shrew mole in particular by having: (i) a partially unfused bicipital tunnel, (ii) a longer teres tubercle, (iii) a lesser distance between the teres tubercle and the lesser tuberosity, (iv) the presence of the scalopine ridge, (v) metacristid of the p 4 in stright line, (vi) less robust mandible, (vii) presence of the p3, (viii) presence of the talonid notch.

Urotrichus dolichochir : This species presents clear Urotrichine affinity. It resembles the ex species Urotrichus talpoides in both size and shape of the humerus. Urotrichus dolichochir presents some primitive humeral features compared with extant Urotrichini such as an even small teres tubercle, open bicipital tunnel and a more slender shaft of the humerus. Rzebikia polonica differs from this species mainly for the same characters expressed for U. talpoides .

Dymecodon pilirostris : This species has been considered for long time as a congeneric member of Urotrichus because of the strong similarities in their morphology ( Kawada and Obara 1999). Rzebikia polonica is different from the lesser Japanese shrew mole by the same features of U. talpoides .

Quyania chowi : Rzebikia polonica resembles Q. chowi in many features (see Storch and Qiu 1983 for a detailed description) whereas it is distinct from the Chinese species by having: (i) a more rounded and larger teres tubercle, (ii) a partially unfused bicipital tunnel, (iii) a shorter distance between the teres tubercle and the lesser tuberosity, (iv) a weaker development of the cingula, (v) unbent lingual side of the lower molars, (vi) more conspicous protoconules of the M1 and M2, (vii) parastyle of the M2 separated from the paracrista.

Quyania europaea Rzebik-Kowalska, 2014 : Rzebikia polonica differs from the European species of Quyania by having: (i) more robust shaft of the humerus, (ii) larger teres tubercle, (iii) more evident and straight scalopine ridge, (vi) partially unfused bicipital tunnel, (v) the presence of vestigial mesoconids, (vi) mental foramen situated under the p3.

Neurotrichus columbianus Hutchinson, 1968 : According with Storch and Qiu (1983) and Popov (2004), Neurotrichus columbianus should be related to the genus Yanshuella Storch and Qiu, 1983 and does not belong to Neurotrichini tribe at all.

Stratigraphic and geographic range.—Pliocene–Pleistocene boundary, Poland, Ruscinian–Villanyian (MN15, MN16) boundary, locality Węże 2.