Witenia de Bruijn, Ünay, Saraç, & Yïlmaz,

Maridet, Olivier, Codrea, Vlad A., Fărcaș, Cristina, Solomon, Alexandru A., Venczel, Márton & Tissier, Jérémy, 2025, The record of cricetid rodents across the Eocene-Oligocene transition in Transylvania, Romania: implications for the “ Grande Coupure ” at European scale, Acta Palaeontologica Polonica 70 (2), pp. 291-327 : 299-303

Genus Witenia de Bruijn, Ünay, Saraç, & Yïlmaz,

2003 Type species: Witenia flava de Bruijn, Ünay, Saraç, & Yïlmaz, 2003 ;

Süngülü A, upper Eocene?, Turkey.

Witenia sp.

Fig. 8A, B.

Material.— Two lower molars from Treznea, Priabonian, upper Eocene, Turbuța Formation, MeseȘ sedimentary area, Transylvanian Basin, Romania.

Measurements.—See Table 2. Description.—Both molars have bulk cuspids with a relatively high crown compared to other late Eocene specimens studied herein.

The m1 has no anterolophulid nor anteroconid but has a metaconid spur connecting the anterolophid to the metaconid. The metaconid is much more mesially located than the protoconid, with its tip very close to the antero-lingual border of the tooth. The metaconid and the protoconid are connected by a long V-shaped protoconid hind arm. The metaconid ridge is thick and ends with a strongly developed mesostylid, but does not totally close the mesosinusid, whereas a low and weakly developed cingulid closes the sinusid labially. The entoconid is transversally elongated and shows a shot distal spur. The posterosinusid is large and surrounded by a long and strongly curved posterolophid. A short labial posterolophulid delimits a small posterosinusid. The roots are not preserved.

The m3 has thick anterolophids, but not reaching the metaconid and the protoconid so the metasinusid and protosinusid remain open, respectively. The protoconid hind arm is large, oriented backward and reaches the middle of the mesoflexid, whereas the mesolophid is short and is oriented forward. The metaconid ridge is long, without mesostylid, but does not totally close the mesoflexid, whereas a low and weakly developed cingulid closes the sinusid labially. The posterosinusid is nearly closed by a low, but incomplete cingulid. The roots are not preserved.

Remarks.—The two teeth from Treznea show characteristics that are diagnostic of the genus Witenia on lower check teeth (de Bruin et al. 2003): the anteroconid of the m1 developed as a narrow antero-lingually directed crest of the protoconid and the generally large sinusid and lingually closed by an antero-labially postero-lingually directed oblique crest. However, the statistically larger m3 compared to m1, another diagnostic feature of the genus, cannot be observed here based on two teeth only. In addition, the teeth from Treznea are characterized by large and elongated crests (lophodont trend) and large sinusid that differentiate Witenia from most other cricetid genera.

There are so far four species referred to Witenia : Witenia yolua Gomes Rodrigues, Marivaux, & Vianey-Liaud, 2012 ; W. flava de Bruijn, Ünay, Saraç, & Yïlmaz, 2003 ; Witenia fusca de Bruijn, Ünay, Saraç, & Yïlmaz, 2003 , and Witenia europea de Bruijn, Marković, Wessels, & van de Weerd, 2019 . De Bruijn et al. (2018) also tentatively referred a few teeth from Strelac-1, Strelac-3, and Valniš to the the species W. fusca as W. cf. fusca . The m1 from Treznea shows several morphological similarities with W. fusca : the lingually directed spur instead of an anteroconid; the protoconid and metaconid near one another (so the mesial part of the tooth is noticeably narrower than the distal part) and connected by the distal arm of the protoconid; the oblique ectolophid making the shape of a cross with the mesolophid/ectomesolophid; the hypolophid inserted on the ectolophid just in front of the hypoconid; and the long posterolophid with a bulge at its labial extremity. Likewise, the m3 from Treznea shows more similarity with W. fusca : the parallel metalophid and hypolophid directed somewhat mesially and inserting respectively on the protoconid and hypoconid mesial arms; a large sinusid with the long distal arm of the protoconid but a much shorter mesolophid; and a wide strong posterolophid constricted just distally to the entoconid.

The two teeth are otherwise noticeably smaller than in all species of Witenia , including W. cf. fusca from Strelac-1, Strelac-3, and Valniš (the smallest population referred to Witenia so far: de Bruin et al. 2018). We tentatively refer them to Witenia , they might consequently belong to a new and smaller species, but the material is unfortunately insufficient to secure the generic identification and formally de- fine a new species. These two teeth are identified as Witenia sp. until more material is found.

Genus Eocricetodon Wang, 2007

Type species: Eucricetodon meridionalis Wang & Meng, 1986 , Caijiachong , upper Eocene of Yunnan, China

Eocricetodon cf. Eo. meridionalis ( Wang & Meng, 1986)

Fig. 8C–K.

2001 Pseudocricetodon sp. ; Baciu and Hartenberger 2001: 444.

Material.—Seven upper molars and four lower molars from Treznea, Priabonian, upper Eocene, Turbuța Formation, MeseȘ sedimentary area, Transylvanian Basin, Romania.

Measurements.—See Table 3.

Description.— In lateral view, the molars show a low crown with acute cusps and cuspids. On upper molars, especially M2s, when the teeth are not worn out, the paracone appears noticeably higher than the metacone.

M1s are characterized by an elongated and narrow mesial lobe. The anterocone is not divided but is transversally elongated; it is connected to the protocone by a long and well-developed anterolophule. The mesial protolophule is either incomplete or absent whereas the distal one is complete. The paracone spur is either weak or absent. The mesosinus is labially open despite the presence of a well-developed mesostyle. The mesoloph can be short or long, when long it merges with the mesostyle. The mesocone is small with an entomesoloph either very small or absent. One of the M1s Fig. 8D) shows a very small protocone distal arm (sensu Maridet and Ni 2013), much lower and weaker than the entoloph. The metalophule is transverse and connects to the mesial half of the hypocone. The posterosinus is wide and closed labially long posteroloph. The roots are not preserved.

M2s have a strong labial anteroloph whereas the lingual anteroloph is much less developed and lower. One M2 ( Fig. 8E) has a second anterolophule connecting the middle of the labial anteroloph to the mesial protolophule. Another M2 ( Fig. 8F) has a parastyle located labially on the labial anteroloph. Both the mesial protolophule and metalophule are oblique and connected mesially to the protocone and hypocone respectively. The distal protolophule is either weaker than the mesial one, or incomplete or absent. The mesostyle is well developed and linked to the paracone by a paracone distal spur (or postparacrista; Fig. 8E, F). The mesoloph is long and can merge with the mesostyle. One of the M2s shows a very small protocone distal arm, much lower and weaker than the entoloph. The posterosinus is wide and closed labially by the posteroloph. The roots are not preserved.

The only M3 is strongly worn out and partly broken; however, it is possible to observe that the tooth has rounded shape due to much reduced metacone and hypocone. The labial anteroloph bears a very small parastyle. A spur starting between the protolophule and the protocone seem to join the mesoloph to form a small pit in the middle of the tooth. The M3 has three roots.

The only m1 ( Fig. 8H) has a very small anteroconid and a metastylid both next to each other, but no anterolophulid or metalophulid. The labial anterolophid connect directly the anteroconid to the protoconid mesial slop; the lingual anterolophid is very short as the metaconid is much more mesially located than the protoconid, hence close to the metastylid. The metaconid and the protoconid are connected by the curved protoconid hind arm. The metaconid ridge is long and follows the lingual border up to the entoconid so the mesosinusid is closed. The mesoconid is small but well developed. The mesolophid starts from the mesoconid, is large and long but does not reach the lingual border; it is also interrupted in its middle. In contrast, the ectomesolophid is very weakly developed, limited to a fold of the enamel in the middle of the sinusid, and does not seem to connect to the mesoconid or the ectolophid. The hypoconid hind arm is long and ends in the middle of the posterosinusid. There is a little depression between the distal side of the hypoconid and the base of the posterolophid. The roots are not preserved.

The m2s have long and thick lingual and labial anterolophids. The antero-lingual sinusid is closed, whereas the antero-labial one is closed only in one of the two m2s. Both the metalophulid and the protoconid hind arms are present and well developed; the protoconid hind arm bends and connects to the metaconid, but it is slightly lower than the metalophulid. One of the m2s ( Fig. 8I) has short distal spurs starting from the metalophulid and joining the protoconid hind arm. The mesoconid is small but well developed; the mesolophid starts from the mesoconid, it is long but stops in the middle of the mesosinusid. The ectomesolophid also starts from the mesoconid and is short in one m2, but it is absent in the other one. The metaconid ridge is long and reaches the entoconid so the mesosinusid is closed ligually. A cingulid closes the sinusid labially in one m2 but not in the other one. The hypoconid hind arm connects to the hypolophulid in one m2 and is absent in the other. The posterolophid is large and long, it forms a bulge on the distal border and closes the postero-sinusid lingually. One of the m2s has two preserved roots.

The only m3 ( Fig. 8K) has long and thick lingual and labial anterolophids like for m2s. Both the metalophulid and the protoconid hind arm are present and well developed but the protoconid hind arm does not connects to the metaconid. Mesoconid, mesolophid and ectomesolophid are all well developed; both the mesolophid and ectomesolophid start from the mesoconid; the mesolophid is long but does not reach the lingual border whereas the ectomesolophid is short. The metaconid ridge is long and reaches the entoconid so the mesosinusid is closed ligually whereas the sinusid remains open labially. The posterolophid forms a loop and connects to the hypolophulid delimiting a small rounded posterosinusid. An additional small depression exists between the posterolophid, the entoconid and a cingulum that follows the postero-lingual border. The tooth has two roots.

Remarks.— With a well-developed mesial lobe in M1, a small but also well-developed anteroconid in m1, the occurrence of a hypoconid hind arm in m1–2, and the reduced third molars, these teeth from Treznea show all the characteristics of a small eucricetodontine species. Among small size eucricetodontines, the teeth from Treznea noticeably differs from Lignitella suemengeni Ünay-Bayraktar, 1989 , in having a hypoconid hind arm in m1–2 and being noticeably bigger, and from Oxynocricetodon erenensis Wang, 2007 , in having a complete anterolophule and a long mesoloph in M1, and a much reduced M3.

Among Eocene and Oligocene eucricetodontines, many species have been referred to the genus Eucricetodon , and the genus or subgenus Atavocricetodon : Eu. ( A.) atavoides Freudenthal, 1996 ; Eu. ( A.) atavus Misonne, 1957 ; Eu. ( A.) hugueneyae Freudenthal, 1996 ; Eu. ( A.) minusculus Freudenthal, 1996 ; Eu. ( A.) nanoides Freudenthal, 1996 ; Eu. A.) nanus Peláez-Campomanes, 1995 ; Eu. ( A.) paaliensis Marivaux, Vianey-Liaud, & Welcomme, 1999 ; Eu. caducus Shevyreva, 1967 ); Eu. huberi ( Schaub, 1925) ; Eu. huerzeleri Vianey-Liaud, 1972 ; Eu. leptaleos ( Wang & Meng, 1986) ; Eu. murinus (Schlosser, 1884) ; Eu. asiaticus (Matthew & Granger, 1923) ; Eucricetodon occasionalis Lopatin, 1996 ; Eu. praecursor ( Schaub, 1925) . All these species differ from the above described specimens of Treznea in having more robust cusp(id)s, stouter loph(id)s, a larger mesial lobe in M1, in missing the long and complete anterolophule (this morphology is very rare in the Eucricetodon / Atavocricetodon group, and the anterolophule is stouter and better developed in the rare cases when it occurs, e.g., see Freudenthal 1996), often shorter mesolophs and mesolophids with less developed mesostyl(id)s, and better developed anteroconid in m1 with a longer mesial lobe. The teeth from Treznea show nevertheless some similarities with Eu. (A.) kurthi de Bruijn, Ünay, Saraç, & Yïlmaz, 2003 in having an elongated and narrow mesial lobe, a long mesoloph in M1 and M2 sometimes reaching the labial cingulum, a small and rounded M3 with very weakly developed hypocone and metacone in M3. Nevertheless, they still noticeably differ from it in being larger, in having a complete anterolophule on M1, both protolophules but with a less developed distal one in M2, and the mesial protolophule connecting directly to anteroloph in M3.

The long but narrow mesial lobe with a well-developed and complete anterolophule in M1 associated with a poorly-developed anterocone in M1 are in fact characteristic of another genus tentatively referred to Eucricetodontines but never described in Europe so far: Eocricetodon Wang, 2007 . The diagnosis of this genus describes indeed many morphological characters also observed in Treznea such as the obtuse main cusps and slender lophs, the elongated and narrower anterior lobe, single anterocone, and complete thin anterolophule in M1, the well-developed mesostyle and mesoloph in upper molars, the ml and m2 of subequal length, the short mesial part (trigonid) and the weakly-developed anteroconid without metalophid I and anterolophid in m1, and metaconid and entoconid more mesially located than protoconid and hypoconid in m2. The only main difference is the presence of well-developed distal arm of hypoconid in the m1 and m2 of Treznea whereas the feature is considered absent in the diagnosis of Eocricetodon . It is, however, worth noticing that both the m1 figured in Wang (2007: fig. 4C) and the m2 figured in Wang and Meng (1986: pl. 1: 8) show a little bulge at the base of the posterolophid which could indicate that this feature is not really absent but rather weakly developed. There are so far two species referred to this genus: Eocricetodon meridionalis ( Wang & Meng, 1986) and Eocricetodon borealis Wang, 2007 . The two species are very similar in size and morphology, but Eo. meridionalis slightly differs by the absence of protoconule in m1, the larger and more mesially located metaconid and complete distal metalophid in m1, and the the transverse mesial metalophid connecting mesially to protoconid in m2. The teeth from Treznea show the same features thus displaying a size and morphology very close to Eo. meridionalis at the exception of the distal well-developed arm of hypoconid in m1 and m2. Therefore, we tentatively refer these specimens from Treznea to this species as Eo. cf. Eo. meridionalis , which indicates the first occurrence of this genus outside Asia.

Genus Bustrania de Bruijn, Marković, Wessels, & van de Weerd, 2019

Type species: Bustrania dissimile de Bruijn, Marković, Wessels, & van de Weerd, Buštranje , upper Eocene , Serbia .

Bustrania cf. B. dissimile de Bruijn, Marković, Wessels, & van de Weerd, 2019

Fig. 8L, M.

2001 Atavocricetodon cf. nanoides ; Baciu and Hartenberger 2001: 444.

Material.—One upper molar and one lower molar from Bociu, Priabonian, upper Eocene, Jebucu Formation, Gilău sedimentary area, Transylvanian Basin, Romania.

Measurements.—See Table 4. Description.—In lateral view, the molars are characterized by a low crown, slender and less acute cusp(id)s compared to Eo. cf. Eo. meridionalis from Treznea; also, as opposed to Eo. cf. Eo. meridionalis from Treznea, the paracone of the M2 is not noticeably higher than the metacone.

The M2 ( Fig. 8L) has a long labial anteroloph ending by a little parastyle whereas the lingual anteroloph is lower and much shorter so the protosinus is limited to a small pit mesial to the protocone. The protocone spur is present but is short and a second small spur projects into the anterosinus from the paracone. The paracone also has a well-developed distal spur ending by a mesostyle. A small cingulum is present on the labial border just distal to the paracone; it merges with the paracone distal spur to form a small pit. The mesostyle and the metacone are not connected so the mesosinus remains labially open. A cingulum is also present lingually; it is connected to the hypocone, thick but short, so the sinus remains open lingually. Both the entoloph and the protocone distal arm are well developed; they connect the protocone to a large mesocone. The mesoloph is short and starts from the mesial part of the mesocone whereas the metalophule connects to the distal part of the mesocone (and not to the hypocone). The posteroloph is long, delimiting a wide posterosinus. The roots are not preserved.

The m2 ( Fig. 8M) has a long lingual anterolophid but a short labial anterolophid so the protosinusid remains open labially. There is no metaconid ridge but a small mesostyle; nevertheless, the mesosinusid remains open lingually. Likewise, the sinusid is opened labially. The protoconid hind arm is long but ends in the mesosinusid. The mesolophid starts from the mesoconid and is short; it ends in the mesosinusid. Additionally, a little spur starts from the mesolophid extremity and is oriented towards the hypolophulid. The ectolophid is lower and weaker mesially to the mesoconid (between the protoconid hind arm and the mesoconid) than distally (between the mesoconid and the hypolophulid). The entolophulid is straight and connects to the ectolophid, mesially to the hypoconid. The tooth has no hypoconid hind arm, no labial posterolophulid or labial posterosinusid, but the posterolophid is long and delimits a wide posterosinusid. The roots are not preserved.

Remarks.— These teeth represent the smallest cricetid found so far in the upper Eocene of Transylvania. They are characterized by a low crown, thin crests and gracile cusp(id) s, the sinus(id) oriented backward, and a mesosinus much larger than the sinus in M2 and a mesosinusid much larger than the sinusid in m2 (due to the lingual position of the entoloph and the labial position of the entolophid respectively). Additionnaly the protocone distal arm is long, almost longitudinal and connects directly to the mesial arm of the hypocone, which is a characteristic only seen in taxa referred to Paracricetodontinae or Pappocricetodontinae ( Maridet and Ni 2013; de Bruijn et al. 2018). The above-described morphological features ressemble that of Bustrania dissimile de Bruijn, Marković, Wessels, & van de Weerd, 2019 , from the Eocene of Serbia (Buštranje). One of the diagnostic features if B. dissimile is the high morphological variability composed by an “irregular array of low ridges and cuspules” and “the complex unstable pattern within the main basins” (de Bruijn et al. 2019: 522). With only two teeth, such a variabililty can not be observed here. However, the M2 from Bociu shows a complexe pattern with several spurs starting from the protocone, the paracone and the mesostyle. Likewise, the m2 also shows a very irregular entolophid and a small isolated spur starting from the mesolophid. The teeth from Bociu only differ from B. dissimile from Buštranje in being slightly larger and missing the hypoconid hind arm in m2, although this character is very variable and is not always present in B. dissimile . We consequently tentatively refer the teeth from Bociu to this species as B. cf. B. dissimile