FOSS I L I MP RI N T • vo l. 77 • 2021 • no. 1 • p p. 1 2 6 –1 4 4 THE AMPHICYONINAE (AMPHICYONIDAE, CARNIVORA, MAMMALIA) OF THE EARLY MIOCENE FROM TUCHOŘICE, THE CZECH REPUBLIC JORGE MORALES1, OLDŘICH FEJFAR2, ELMAR HEIZMANN3, JAN WAGNER2, ALBERTO VALENCIANO4, JUAN ABELLA5,6,* 1 Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, C/José Gutiérrez Abascal 2, 28006, Madrid, Spain; e-mail: jorge.morales@mncn.csic.es. 2 Department of Palaeontology, National Museum, Václavské nám. 68, 110 00 Prague 1, the Czech Republic; e-mail: oldrich.fejfar@natur.cuni.cz, jan.wagner@nm.cz. 3 Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany; e-mail: elmar.heizmann@smns-bw.de. 4 Departamento de Ciencias de la Tierra and Instituto Universitario de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Area de Paleontología., C/ Pedro Cerbuna, 12, 50009, Zaragoza, Spain; e-mail: a.valenciano@unizar.es. 5 Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/ Columnes s/n, Campus de la UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain; e-mail: juan.abella@icp.cat. 6 Instituto Nacional de Biodiversidad, Pje. Rumipamba N. 341 y Av. de los Shyris (Parque La Carolina) Quito, Ecuador. * corresponding author Morales, J., Fejfar, O., Heizmann, E., Wagner, J., Valenciano, A., Abella, J. (2021): The Amphicyoninae (Amphicyonidae, Carnivora, Mammalia) of the early Miocene from Tuchořice, the Czech Republic. – Fossil Imprint, 77(1): 126–144, Praha. ISSN 2533-4050 (print), ISSN 2533-4069 (on-line). Abstract: The Amphicyoninae of the early Miocene from the locality of Tuchořice, the Czech Republic, are represented by three species. Two of them are classified within the tribe Amphicyonini: Paludocyon bohemicus (Schlosser, 1899) as the type species of Paludocyon n. gen., and a large-sized amphicyonid determined as Megamphicyon carnutense (Antunes et Ginsburg, 1977). Dehmicyon n. gen. aff. schlosseri is determined by two small teeth. This new genus has been proposed for the species Amphicyon schlosseri Dehm, 1950 from Wintershof-West and is tentatively included in the tribe Pseudarctini nov. together with the genera Ictiocyon and Pseudarctos. This association of Amphicyoninae provides valuable information on the taxonomy and systematics of this subfamily during the early Miocene, at which time important environmental changes were taking place in Europe, which undoubtedly affected the evolution of Amphicyonidae. Key words: Amphicyonidae, Amphicyoninae, systematics, early Miocene, Europe Received: April 20, 2021 | Accepted: July 21, 2021 | Issued: December 9, 2021 Zoobank: http://zoobank.org/urn:lsid:zoobank.org:pub:8C73FDF8-9155-4700-B53A-185CF3394B6B Introduction taxonomic assignation. As a result of this study, this species is now determined as Paludocyon n. gen. bohemicus, which The early Miocene (MN 3) Amphicyonidae of Tuchořice is relatively similar to Heizmannocyon, a taxon proposed (the Czech Republic) are represented by two subfamilies; by Ginsburg (1999) as a subgenus of Amphicyon, which Thaumastocyoninae Hürzeler, 1940, which contains a is considered herein as possessing a generic status. The unique species (Morales et al. 2019), and Amphicyoninae Amphicyoninae of Tuchořice are also represented by Trouessart, 1885, with three species varying greatly in a small sized species, Dehmicyon aff. schlosseri (Dehm, size from almost the smallest to the biggest species of this 1950), which is related to the Ictiocyon-Pseudarctos subfamily; they represent the first morphological stages group, and by the giant-size Megamphicyon carnutense of two different evolutionary lineages. Tuchořice is the (Antunes et Ginsburg, 1977). The present paper attempts to type locality of Pseudocyon bohemicus Schlosser, 1899, conduct a systematic study of these Amphicyoninae which a species with a controversial systematic status. However, should make a significant contribution to the knowledge remains obtained in a relatively recent field campaign of the early stage of European Miocene Amphicyoninae (Fejfar et al. 2003) enabled us to perform a more accurate radiation. DOI 10.37520/fi.2021.011 Tuchořice locality and crushing molars (m2, M1 and M2) with a highly developed occlusal surface. The fossiliferous locality of Tuchořice is located in North Bohemia, the Czech Republic, close to the southern I n c l u d e d t r i b e s . Amphicyonini, Pseudarctini n. margin of the Chomutov-Most brown coal basin near the tribe, Magericyonini n. tribe. villages of Tuchořice and Lipno (Fejfar and Heizmann R e m a r k s . The taxonomy and systematics of the 2016 and references herein). Tuchořice mammal remains Miocene Amphicyonidae is highly complex (e.g., Kuss are found associated with freshwater travertine sediments, 1965, Viranta 1996, Hunt 1998, Ginsburg 1999, Peigné et al. the site has been known since the nineteenth century (Reuss 2008, Morales et al. 2016), and the reasons for this are well and Meyer 1851, Suess 1861) and is considered one of known: 1) proliferation of taxa, often with descriptions and the classical European Miocene mammal localities. It is definitions based on scarce and sometimes uncharacteristic characterized by the abundance of carnivoran mammals, fossils; 2) a dental morphology displaying very limited with a predominance of amphicyonid species (Fejfar et al. variability, associated with a wide size range and the 2003, Fejfar and Heizmann 2016, Morales et al. 2019). presence of different species in the same locality. According to Ginsburg (1999), the subfamily Amphicyoninae is represented by 6 genera in Europe: Material and methods Amphicyon Lartet, 1836, Cynelos Jourdan, 1862, Pseudocyon Lartet, 1851, Ysengrinia Ginsburg, 1966, Nomenclature and measurements Pseudarctos Schlosser, 1899 and Ictiocyon Crusafont, Dental nomenclature follows Ginsburg (1999). Mea- Villalta et Truyols, 1955. Moreover, he recognized three surements were made to the nearest 0.1 mm using Mitutoyo additional subgenera for Amphicyon: Megamphicyon Kuss, Absolute digital callipers. The material studied is displayed 1965, Euroamphicyon Viranta, 1996 and Heizmannocyon in Tables 1 and 2. A bivariate diagram of Width/Length of Ginsburg, 1999. These subgenera are considered to have P4, M1, M2, m1 and m2, and also of Length P4/Length M1, been included in a generic rank in the present research. With Length M1/Length M2, Length m1/Length m2 and Length the exception of Ysengrinia, which has been transferred to p4/Length m1 of the small and middle-sized species studied the Thaumastocyoninae (Heizmann and Kordikova 2000, in the present research can be seen in Text-figs 1 and 2 Morales et al. 2019), the remaining genera of the subfamily, respectively. with the addition of the two new genera defined herein, can In the past, the material from Tuchořice was published be classified into three groups, for which we propose the under several provisional numbers (see e.g., Fejfar and taxonomic rank of a tribe. Heizmann 2016). At present, all the material is housed in Amphicyonini Trouessart, 1885, comprising Amphi- the Department of Palaeontology, National Museum, Prague cyon, Cynelos, Paludocyon n. gen., Heizmannocyon, under the inventory numbers beginning with Pv (except the Megamphicyon and Euroamphicyon. This group included specimens housed in Naturhistorisches Museum Wien). the most typical Amphicyoninae; its molar dentition tends to present an increased surface area, the carnassials are robust Institutional abbreviations and the premolar dentition progressively decreases in size BSP Bavarian State Collections of Palaeontology and and complexity. Geology, Munich, Germany Pseudarctini tribe nov. comprising the genera Pseudarctos FS Faluns d’Anjou, France; casts stored at the and Ictiocyon. As in the previous group, the molars tend to MNCN, Madrid, Spain present a larger crushing surface, albeit displaying a dif- MNHN Muséum national d’Histoire naturelle, Paris, ferent pattern with a greater mesiodistal length in the upper France molars and buccolingual length in the lower molars. This is MNCN Museo Nacional de Ciencias Naturales, Madrid, associated with a significant reduction of the carnassial teeth, Spain and loss of the p4 distal accessory cuspid. Dehmicyon n. gen. NMB Naturhistorisches Museum Basel, Basel, is provisionally included as a basal form of this tribe. Switzerland Magericyonini tribe nov. comprising genus Magericyon NM National Museum, Prague, the Czech Republic and with some doubt also Pseudcyon. Magericyonini (inv. no. Pv) represents a new attempt to develop an advanced TU Provisional numbers used by O. Fejfar for hypercarnivore adaptation in the Amphicyonidae, while Tuchořice specimens remaining closely related to the amphicyonines, but differing from the Thaumastocyoninae in the slightly reduced crushing dentition and in the morphology of the upper and Systematic palaeontology lower carnassials, which retain an Amphicyonini pattern. Order Carnivora Bowdich, 1821 Tribe Amphicyonini Trouessart, 1885 Suborder Caniformia Kretzoi, 1943 Infraorder Arctoidea Flower, 1869 T y p e g e n u s . Amphicyon Lartet, 1836. Family Amphicyonidae Trouessart, 1885 E m e n d e d d i a g n o s i s . Amphicyoninae with Subfamily Amphicyoninae Trouessart, 1885 molar dentition tending to increase the molar surface area, E m e n d e d d i a g n o s i s . Amphicyonidae with robust the carnassial teeth are robust and the premolar dentition carnassials (m1/P4), P4 tends to have a reduced protocone progressively decreases in size and complexity. 127 E u r o p e a n g e n e r a i n c l u d e d . Amphicyon, placed in a central position; 4) a short robust P4, with the Megamphicyon, Euroamphicyon, Cynelos, Heizmannocyon protocone distally displaced and reduced; 5) M1 showing and Paludocyon n. gen. a trapezoidal occlusal shape, enlarged trigone and reduced lingual area ; 6) M2 with a longer buccal wall and a shortened Genus Paludocyon n. gen. buccolingual diameter. T y p e a n d o n l y s p e c i e s . Pseudocyon bohemicus Paludocyon bohemicus (Schlosser, 1899) Schlosser, 1899. Text-figs 1–4, Tabs 1a, 2a E t y m o l o g y . From the Latin paludes, which means 1861 Amphicyon intermedius Mey.; Suess, p. 224, pl. II. swampy areas, in relation to the marshy/ lacustrine sediments 1868 Amphicyon intermedius H. v. Meyer; Peters, p. 190. from the locality of Tuchořice. 1899 Pseudocyon bohemicus n. sp.; Schlosser, p. 124, pl. XIV, figs 3, 4, 9. D i a g n o s i s . Medium sized Amphicyonini, lower 1901 Amphicyon bohemicus Schlosser; Schlosser, p. 62, pl. I, premolar row without diastemas, p4 small, with wide figs 18, 23–26, 29, 30. talonid. The m1 is robust, trigonid with low paraconid and 1929 Amphicyon bohemicus Schloss.; Viret, p. 113. large metaconid. The talonid is wider than the trigonid; 1965 Amphicyon steinheimensis bohemicus (Schlosser) 1899; it comprises a strong, high hypoconid, the lingual base is Kuss, pp. 40–46, figs 16–23. thickened apically, and has a subdivided entoconid. The m2 1973 Amphicyon bohemicus; Heizmann, pp. 17–20. is short in comparison with the m1, and presents a reduced 1977 “Amphicyon” bohemicus; Ginsburg, pp. 94–95. entoconid. P4 slender, with mesially elongated paracone 1999 Cynelos (Heizmannocyon) bohemicus (Schlosser, 1899); and weak parastyle; the protocone is relatively strong and Ginsburg, p. 116. mesially located. The M1 shows two morphotypes, one 2000a Cynelos (Heizmannocyon) bohemicus (Schlosser) 1899; Ginsburg, p. 11. subtriangular due to the narrowed lingual area, and the 2003 Amphicyon bohemicus; Hunt, p. 105. second with a subquadrangular lingual area. The paracone 2008 C[ynelos] bohemicus; Peigné et al., p. 954. is high compared to the metacone. The metaconule is broad 2015 Cynelos bohemicus; Hunt and Stepleton, p. 2. and clearly differentiated from the protocone. The M2 has 2016 Amphicyon bohemicus (Schlosser 1899); Fejfar and Heiz- a quadrangular occlusal shape, with a short buccal wall and mann, p. 320, figs 9, 10, 11.1–5+11–17. a wide transversal diameter; metacone reduced. M3 and m3 2020 Cynelos cf. bohemicus (Schlosser 1899); Jiangzuo et al., reduced, with simple morphology. p. 23, fig. 4.4–6. D i f f e r e n t i a l d i a g n o s i s . Paludocyon n. gen. L e c t o t y p e . NM-Pv 11677, left m1, figured by differs from Pseudocyon sansaniensis Lartet, 1851 (type Schlosser (1899: pl. 14, fig. 4; Text-fig. 4a herein). Lectotype species of Pseudocyon) in the greater robustness of its designated by Kuss (1965: 41; he listed it under the old m1 and m2; the greater width of the m1 talonid and in its number 4330). strong hypoconid which occupies almost the entire area of P a r a l e c t o t y p e s . NM-Pv 11678 (old no. 4329), left the talonid; additionally, the p4 and m2 exhibit a smaller P4, figured by Schlosser (1899: pl. 14, fig. 3); NM-Pv 11679 reduction compared to the m1. It differs from Cynelos in right incomplete M2, and NM-Pv 11731 right complete M3 the limited development of the distal molars (M2/M3 and (both old no. 205/1), figured by Schlosser (1899: pl. 14, fig. m2/m3) compared with the first molars; it also differs in 3); and NM-Pv 11680 (old no. 4310) left m3, figured by the significant reduction of the lower premolars, including Schlosser (1899: pl. 14, figs 4 and 9). p4; the greater width of the m1 talonid in relation to the trigonid and the greater height and size of its hypoconid, T y p e l o c a l i t y . Tuchořice, the Czech Republic. together with the reduction of the entoconid. The P4 of A g e . Early Miocene, MN 3. Paludocyon n. gen. has an elongated paracone mesial crista, whereas in Cynelos it is short and more vertical. The D i a g n o s i s . Same as genus. metacone of the M2 is smaller than the paracone, while in A d d i t i o n a l m a t e r i a l f r o m t y p e l o c a l i t y. Cynelos lemanensis both are similar in size. Differences NM-Pv 11681 (TU 7391149), left P4; NM-Pv 11682 (TU when compared to Amphicyon major Blainville, 1841 7391150), left P4; NM-Pv 11683 (TU 739113), right P4; are also evident. Apart from the larger size, its dentition is NM-Pv 11684 (TU 739155), left P4; NM-Pv 11685 (TU characterized by the great width of the crushing dentition. 739176), right M1; NM-Pv 11686 (TU 7391150), left M1; Additionally, the A. major m1 trigonid is better developed NM-Pv 11687 (TU 739185), M2 right; NM-Pv 11688 (TU than that in the Paludocyon species. Paludocyon also differs 739149), left M2; NM-Pv 11689 (TU 739122), right M2; from Amphicyon in the reduced development of the distal NM-Pv 11690 (TU 7391150), left M2; NM-Pv 11691 (TU molars relative to the first molars. This relatively small 739165), right M3; NM-Pv 11692 (TU 739185), left M3; size of the distal molars in Paludocyon also enables it to NM-Pv 11695 (TU-739157), right mandible with p2–m2; be differentiated from Megamphicyon, which has large NM-Pv 11697 (TU 739135), right mandible with p3–m3; distal molars. Paludocyon differs from Heizmannocyon as NM-Pv 11698 (TU 739142), association of right p4, m1 and the latter shows more specialized characters, such as: 1) the m2; NM-Pv 11699 (TU 739141), left mandible with p3–m3; presence of more developed diastemas between the lower NM-Pv 11700 (TU 739177), left mandible with canine, premolars; 2) the strong reduction of the lower premolars, p1–p2 alveolus and p3–m2; MN-Pv 11722, association of including p4; 3) a higher m1 with a stronger hypoconid, left p4–m3. 128 b a c d e Text-fig. 1. Bivariate diagram of length and width of the upper dentition of selected European small and middle size Amphicyoninae compared with the Tuchořice specimens. a: P4; b: M1; c: M2; d: m1; e: m2. Data from Schlosser (1899, 1904), Thenius (1949), Dehm (1950), Heizmann (1973), Ginsburg (1977, 1989), Peigné (2012). Dotted line – ranges of maximum and minimum values from the average of teeth of Cynelos lemanensis from Ulm (Peigné and Heizmann 2003). Abbreviations: L – length; W – width. D e s c r i p t i o n . NM-Pv 11678, left P4 (paralectotype, from the cingulum. The union with the base of the paracone Text-fig. 3a). Well-developed basal cingulum, especially in is not rectilinear, marking a clearly pronounced inflection. the lingual wall. The protocone is located in a mesial position; There is no isolated parastyle, although the mesial crista of it is wide but not very prominent or clearly differentiated the paracone bifurcates before reaching the base of the tooth. 129 a b c d Text-fig. 2. Bivariate diagram of length and width of the lower dentition of selected European small and middle size Amphicyoninae compared with the Tuchořice specimens. a: length P4 and M1; b: length m1 and m2; c: length M1 and M2; d: length m1 and p4. Symbols the same as in Text-fig. 1. Data from Schlosser (1899, 1904), Thenius (1949), Dehm (1950), Heizmann (1973), Ginsburg (1989), Peigné (2012). Dotted line – ranges of maximum and minimum values from the average of teeth of Cynelos lemanensis from Ulm (Peigné and Heizmann 2003); solid line – ranges of maximum and minimum values from the average of teeth of Cynelos lemanensis from Saint Gérand (Ginsburg 1977). Abbreviations: L – length. One of the branches is directed towards the protocone and developed and with a mesiolingually strong basal cingulum. the other mesiobuccally. The paracone is tall and pyramidal The paracone is high compared to the metacone. Small and the metastyle is relatively long. Both paracone and parastyle and metastyle. Paraconule and metaconule metastyle display vertical wear facets on the lingual side. differentiated from the protocone cristae, almost NM-Pv 11681, left P4 (Text-fig. 3b). Differs from the symmetrical in comparison to the transversal axis of the former P4 in which the paracone mesial crista is more molar; metaconule larger than paraconule. Very large but pronounced before reaching the basal cingulum. The low dune-form protocone. Trigone valley sub-rounded. protocone is somewhat smaller and the mesial inflection NM-Pv 11686, left M1 (Text-fig. 3e). Differing from between the base of the protocone and the paracone is less the previous M1 in the greater development of the lingual marked. NM-Pv 11682, right P4, is similar in morphology cingulum, which completely surrounds the protocone, from to the previous specimen, with a more reduced protocone the base of the paraconule to the base of the metaconule, and and without the inflexion at the junction between the bases also a wider lingual area. of the paracone and the protocone. NM-Pv 11683, right P4, NM-Pv 11687, M2 right (Text-fig. 3f). Sub-quadrangular has the same morphology to that of the paralectotype (NM- in shape, with a short buccal wall and a wide transverse Pv 11678). NM-Pv 11684, left P4 (Text-fig. 3c), is somewhat diameter in comparison with the M1. Moderately high buccal larger than the other P4s and possesses a particularly wide cusps. Strong buccal cingulum, especially at the base of the protocone. paracone. Low protocone forming a single semicircular NM-Pv 11685, right M1 (Text-fig. 3d). Molar with crista which reaches the base of both the paracone and subtriangular occlusal shape; it is relatively short, with the metacone. Very strong lingual cingulum, which is a distally projected narrowed lingual area, moderately semicircular and completely surrounds the protocone. 130 a1 b1 c1 d1 e1 a2 b2 e2 d2 c2 a3 b3 c3 i1 a4 e3 g1 0 1 2 cm j k f g2 h i2 Text-fig. 3. Paludocyon bohemicus (Schlosser, 1899), from Tuchořice, the Czech Republic, upper teeth. a: NM-Pv 11678, left P4 (paralectotype), a1 – occlusal view, a2 – buccal view, a3 – lingual view, a4 – mesial view; b: NM-Pv 11681, left P4, b1 – occlusal view, b2 – buccal view, b3 – lingual view; c: NM-Pv 11684, left P4, c1 – occlusal view, c2 – buccal view, c3 – lingual view; d: NM- Pv 11685, right M1, d1 – occlusal view, d2 – buccal view; e: NM-Pv 11686, left M1; e1 – occlusal view, e2 – buccal view, e3 – distal view; f: NM-Pv 11687, right M2 in occlusal view; g: NM-Pv 11688, left M2, g1 – buccal view, g2 – occlusal view; h: NM-Pv 11689, right M2 in occlusal view; i: NM-Pv 11690, left M2, i1 – buccal view, i2 – occlusal view; j: NM-Pv 11692, left M3 in occlusal view; k: NM-Pv 11691, right M3 in occlusal view. Other M2s such as Pv 11688 (Text-fig. 3g), NM-Pv 11689 NM-Pv 11700, left mandible with canine, p1–2 alveolus (Text-fig. 3h) and NM-Pv 11690 (Text-fig. 3i) are similar in and complete p3–m2 (Text-fig. 4b). It corresponds to a small morphology to the previously described M2. specimen, but the dentition is morphologically similar to that NM-Pv 11691, right M3 (Text-fig. 3j), small molar of other specimens. The p1 and p2 alveoli are uniradiculated with reduced metacone. Central protocone opposite to the and reduced, a large diastema is developed between canine–p1 paracone, both are joined by a circular serrated crista. Strong and p1–p2. buccal and lingual cingula. The left M3 NM-Pv 11692 NM-Pv 11695, right mandible with p2–m2 (Text-fig. (Text-fig. 3k) is somewhat smaller than the previous 4c), mesial premolars practically unicuspidated; the p3 is specimen, differing in the complete loss of the metacone. unicuspid; the p4 is quite well developed, as is the main NM-Pv 11677, left m1 (lectotype, Text-fig. 4a). Very cuspid, which is higher than the m1 paraconid; a clearly robust molar, with a short paraconid presenting a vertical separated and relatively acute distal cuspid is present. The mesial cristid. High and very bulky protoconid. Metaconid m1 is very robust, with a short paraconid, mesial cristid quite strong, slightly displaced distally and with the lingual somewhat inclined distally, and very pronounced. High and wall somewhat rounded. Short talonid, almost completely very bulky protoconid, with sharp mesial and distal cuspids. occupied by the hypoconid, the buccal wall of which is Quite strong metaconid, slightly displaced distally and with almost vertical. Low and crestiform entoconid. Small the lingual wall somewhat swollen. Short talonid, almost hypoconulid. Lingually weak basal cingulum, much stronger completely occupied by the hypoconid, the buccal wall of buccally, particularly at the base of the hypoconid, which is which is vertical. Low crestiform subdivided entoconid. thickened apically. Very weak basal cingulids. As in the m1 NM-Pv 11677, 131 Table 1. Measurements in mm of the upper teeth. a: Paludocyon bohemicus (Schlosser, 1899); b: Megamphicyon carnutense (Antunes et Ginsburg, 1977); c: Dehmicyon aff. schlosseri (Dehm, 1950). Abbreviations: TU – Tuchořice; L – mesio-distal diameter; W – width buccal-lingual. the buccal base of the hypoconid is thickened apically. The shortened talonid dominated by a very broad hypoconid. m2 has a moderately high trigonid, with the protoconid and The cuspids are somewhat bunodont although they exhibit metaconid almost the same height, although the protoconid the same morphological arrangement as the previously is better developed. The protoconid presents a weak buccal described m2. widening. Very small paraconid, barely separated from NM-Pv 11697, right mandible with p3–m3 (Text-fig. 4e1–2). the anterior cristids of the protoconid and metaconid; both It differs from NM-Pv 11695 in the greater gracility of the join together, closing mesially the trigonid valley. Wide dentition, especially evident in m1 and m2, additionally the talonid, with a buccal hypoconid, clearly separated from the m2 has a relatively longer talonid. The m3 is sub-rounded protoconid. A low, peripheral and crestiform entoconid is and very small in size with respect to the m2. connected with the distal cristid of the hypoconid, clearly NM-Pv 11699, left mandible with p3–m3 (Text-fig. 4f1– delimiting the talonid valley, which is flat and very wide. 3), in which the mandibular bone is only partially preserved Basal cingulid very weak. in the mesial section (alveolus for p2 and p3–p4 in situ), NM-Pv 11698, association of a right p4, m1 and m2 p3 unicuspid, p4 with a well-developed posterior cusp, and (Text-fig. 4d1–3). Neither the p4 nor the m1 show any a thickened mesial cristid which does not form a distinct differences from those described above. The m2 has a cusp. m1 robust and short, the trigonid is relatively high with 132 b1 a1 b2 a2 b3 a3 0 1 2 cm d1 d2 c1 c2 d3 e1 c3 e2 f1 g1 f2 g2 f3 g3 Text-fig. 4. Paludocyon bohemicus (Schlosser, 1899), from Tuchořice, the Czech Republic, lower teeth. a: NM-Pv 11677, left m1 (lectotype), a1 – buccal view, a2 – lingual view, a3 – occlusal view; b: NM-Pv 11700, left mandible with c, alveoli for p1–p2, and p3–m2, b1 – occlusal view, b2 – lingual view, b3 – buccal view; c: NM-Pv 11695, right mandible with p2–m2, c1 – lingual view, c2 – buccal view, c3 – occlusal view; d: NM-Pv 11698, right p4–m2, d1 – lingual view, d2 – occlusal view, d3 – buccal view; e: NM-Pv 11697, right p3–m3, e1 – occlusal view, e2 – lingual view; f: NM-Pv 11699, left mandible with p3–m3, f1 – lingual view, f2 – occlusal view, f3 – buccal view; g: NM-Pv 11722, left p4–m3, g1 – buccal view, g2 – lingual view, g3 – occlusal view. ­ 133 Table 2. Measurements in mm of the lower teeth. a: Paludocyon bohemicus (Schlosser, 1899); b: Megamphicyon carnutense (Antunes et Ginsburg, 1977). Abbreviations: TU – Tuchořice; L – mesio-distal diameter; W – width buccal-lingual. respect to the talonid, the metaconid is strong. Talonid with with reduced metaconid, and talonid dominated by a strong well-developed entoconid, separated by the narrow valley of hypoconid, the entoconid is subdivided. m2 with a narrow the hypoconid. The m2 is narrow with a highly developed talonid dominated by a strong hypoconid. m3 is more protoconid; the talonid is short with well-developed cusps. compressed buccolingually than in other specimens The m3 is sub-rounded, simple, with only the protoconid clearly pronounced, a cingulum almost surrounding the D i s c u s s i o n . Paludocyon bohemicus was originally entire molar. included by Schlosser (1899) in Pseudocyon, but its MN-Pv 11722, association of left p4–m3 (Text-fig. systematic position has since aroused controversy (Schlosser 4g1–3). The p4 is tall, with the distal part widened. m1 1891, Kuss 1965). Ginsburg (1999), in his review of the 134 Miocene carnivorans of Europe, included it in the clade Miocene Halamagai Formation from Northwestern China. comprising Amphicyon (Heizmannocyon) bohemicus- The material is scarce and alternatively to its determination steinheimensis with Amphicyon steinheimensis Fraas, 1885, as two different forms, the three specimens (M1, M2 and m2) choosing the latter as the type species of the new subgenus. could correspond to a single species, clearly determined by Peigné et al. (2008) considered this subgenus as a synonym these authors as Cynelos cf. helbingi. of Cynelos, and even pointed out the difficulties involved in relating these two species. Hunt (2003), without establishing Genus Megamphicyon Kuss, 1965 its validity, points out that Heizmannocyon would be closer 1965 Megamphicyon; Kuss, p. 66. to Cynelos than to Amphicyon, an observation most likely influenced by the retention of primitive dental characters in T y p e s p e c i e s . Canis giganteus Schinz, 1825 Cynelos, as is also the case in P. bohemicus. (assigned to genus Amphicyon as Amphicyon giganteus by As we have pointed out in the differential diagnosis of Laurillard (1843: 567)). Paludocyon, it differs from Cynelos sufficiently to separate D i a g n o s i s . In Kuss (1965: 66). both genera. Cynelos lemanensis represents a lineage of Amphicyoninae that presents greater development of Megamphicyon carnutense (Antunes et Ginsburg, 1977) the crushing teeth, but has maintained slightly modified Text-figs 5, 6 Tabs 1b, 2b premolars and carnassials. Paludocyon shows a somewhat contrasting trend, characterized by a moderate increase in 1965 Pseudocyon sansaniensis aff. sansaniensis Lartet 1851; the size of the crushing teeth, widening of the m1 talonid, Kuss, pp. 119–122, fig. 77. and a reduction in the size of the lower premolars. Some of 1977 Amphicyon giganteus carnutense; Antunes and Ginsburg, p. 341. these characters are found in Heizmannocyon steinheimensis 1989 Amphicyon giganteus carnutense Antunes et Ginsburg, but the morphology of the upper and lower molars of both 1977; Ginsburg, p. 102, figs 1–4. genera differ to a large extent. The differences between 2000b Amphicyon (Megamphicyon) lathanicus n. sp.; Ginsburg et Paludocyon and Pseudocyon sansaniensis are significant, al., p. 607, fig. 6. as can be seen in our differential diagnosis. However, this 2003 Megamphicyon giganteus; Fejfar et al., p. 167. comparison is limited due to the lack of well-preserved 2016 Megamphicyon ‘major – giganteus’; Fejfar and Heizmann, upper dentition of Pseudocyon sansaniensis, as recognized p. 320, figs 7.2, 12. by Ginsburg (1961) and more recently by Peigné (2012). 2019 Amphicyon carnutense; Jiangzuo et al., p. 2. Morphologically, Heizmannocyon steinheimensis and H o l o t y p e . NMB S.O. 6531, left mandible with Pseudocyon sansaniensis are similar; both share a significant canine and p4–m2. reduction of the p4 as well as a narrow talonid in both the m1 and m2, but H. steinheimensis retains a large m2. T y p e l o c a l i t y . Chilleurs, France. Paludocyon bohemicus is morphologically quite A g e . Early Miocene, MN 3. different from Amphicyon major from Sansan (Ginsburg 1961); indeed, the latter shares many derived characters D i a g n o s i s . In Antunes and Ginsburg (1977). with Cynelos lemanensis, particularly those related to S t u d i e d m a t e r i a l f r o m T u c h o ř i c e . NM- the high degree of development in the crushing dentition. Pv 11701 (TU 738911), right P4; NM-Pv 11703 (TU 738910), Additionally, the m1 of A. major presents better development P4 left; NM-Pv 11704 (TU 73892), left M1; NM-Pv 11705 of the trigonid compared with the Paludocyon and Cynelos (TU 738912), left M2; NM-Pv 11706 (TU 738916), left M3; species (Ginsburg 1961). This mixture of crushing molar NM-Pv 11707 (TU 738920), left M3; NM-Pv 11708 (TU dentition and the high degree of development of carnassial 73898), left p4; NM-Pv 11709 (TU 738919b), left p4; NM- teeth characterizes the Amphicyon species and would appear Pv 11747 (TU 739152), left m1–m3; NM-Pv 11710 (TU to culminate in Megamphicyon. 738918), left m1; NM-Pv 11711 (TU 73896), left m1; NM- Paludocyon bohemicus is absent in the Wintersoft- Pv 11712 (TU 739154), left m1–m2; NM-Pv 11713 (TU West Amphicyonidae association, although some authors 73914), left m2; NM-Pv 11714 (TU 73893), left m2; NM- considered Amphicyon dietrichi Dehm, 1950 as a very similar Pv 11716 (TU 73897), left m2; NM-Pv 11717 (TU 73899), species, and have even proposed to synonymize both species left m2; NM-Pv 11718 (TU 738913), right m2; NM- (Kuss 1965, Peigné et al. 2008, Hunt and Stepleton 2015). Pv 11696 (TU 739120/21), association of right m2 and m3; However, the revision of P. bohemicus makes it possible NM-Pv 11719 (TU 738914a), left m3. to discard such a close relationship. The m1 morphology suggests a greater proximity between A. dietrichi and R e m a r k s . The large-sized Miocene amphicyonids Pseudocyon sansaniensis than with Paludocyon bohemicus. of Western Europe have frequently been determined as A different case could occur with the mandible from the Amphicyon giganteus (Schinz, 1825) or Megamphicyon Thenay site determined as Cynelos bohemicus by Gagnaison giganteus (Schinz, 1825), depending on the authors (Kuss et al. (2012). The excellent preservation of this mandible 1965, Ginsburg and Antunes 1968, Ginsburg 1999, Peigné et shows that the m1 has a very wide talonid, dominated by al. 2006). Some of the large species from the early Miocene a powerful hypoconid, morphologically the dentition is very have been classified in other amphicyonid genera such as close to that of Heizmannocyon steinheimensis, being more Ysengrinia and Crassidia (Heizmann and Kordikova 2000) derived than that of Paludocyon bohemicus. Finally, Jiangzuo and even in Pseudocyon (Ginsburg 1967, 1999, Heizmann et al. (2020) pointed out that the first record of Cynelos cf. and Kordikova 2000). These three genera exhibit different bohemicus, together with Cynelos cf. helbingi, is in the middle degrees of hypercarnivorous dental adaptation (Morales et 135 al. 2019), which serves to separate them from the Amphicyon major group, which reveals a tendency to enlarge the crushing molar surface. From at least the late Oligocene to the middle Miocene, a set of large forms is recorded in Europe, which are close in size and morphology to Amphicyon major, but show some differences which are very difficult to evaluate (Kuss 1965). Increased dental size can be recognised when comparing from a1 the oldest form to the most modern ones, but due to the great c variability in size and morphology, there are real difficulties b1 involved in assigning these fossil assemblages to different taxa. Some of the older forms from the early Miocene (MN 2–3) have received different determinations, including Amphicyon giganteus carnutense Antunes et Ginsburg a2 b2 1977, Amphicyon giganteus laugnacensis Ginsburg, 1989 and Amphicyon (Megamphicyon) lathanicus Ginsburg, Cheneval, Janvier, Pouit et Sen, 2000 (see Ginsburg 2000b, 2002). However, the type species, Megamphicyon giganteus (Schinz, 1825), would be reserved for the largest species a3 with molars similar in size to those from the type locality of Averay (France), also found in some European localities of 0 1 2 cm d e MN 4–6 age (Artenay, Baigneaux, La Romieu, Pont Levoy and Arroyo del Val among others), where molar sizes can Text-fig. 5. Megamphicyon carnutense (Antunes et Ginsburg, greatly exceed that of Amphicyon major (Ginsburg 1989, 1977), from Tuchořice, the Czech Republic, upper teeth. 1999, Peigné et al. 2006). However, there is a need for an in- a: NM-Pv 11701, right P4, a1 – buccal view, a2 – lingual view, depth review of this group, a task that lies beyond the scope a3 – occlusal view; b: NM-Pv 11704, left M1, b1 – occlusal view, of the present research. b2 – mesial view; c: NM-Pv 11705, left M2 in occlusal view; d: NM-Pv 11706, left M3 in occlusal view; e: NM-Pv 11707, left D e s c r i p t i o n . NM-Pv 11701, right P4 (Text-fig. M3 in occlusal view. 5a1–3). Quite elongated, with a relatively long metastyle, and a narrow mesially widened paracone, although without developing an authentic parastyle. The mesial crista of the NM-Pv 11707, left M3 (Text-fig. 5e). Similar in paracone is strogly pronounced, with a small incision near morphology to the M3 described above, but with very poorly the base, which changes its inclination, tending to become developed cusps. The metacone is very small, almost lost. more horizontal and displaced buccally. Consequently, the Occlusal kidney-shaped form. Very strong buccal cingulum, base of the paracone is continued mesially. The protocone is which represents almost the most developed element of the moderate in size, placed in the mesial position, with a poorly molar. separated cusp. Highly developed basal cingulum. NM-Pv 11708, left p4 (Text-fig. 6a1–3). Premolar with NM-Pv 11703, P4 left. This tooth presents an intermediate strong and high distal cuspid. Distolingual cingulid well size, somewhere between the two previous specimens; the developed and talonid moderately expanded. buccal part of the metastyle is broken. The anterior crista of NM-Pv 11709, left p4 (Text-fig. 6b1–3), smaller than the paracone is clearly more vertical than in the other two the previous specimen and differs from it in the strong specimens. constriction of the lingual wall. NM-Pv 11704, left M1 (Text-fig. 5b1–2). Molar with NM-Pv 11710, left m1 (Text-fig. 6c1–3). Very robust a subtriangular occlusal shape, the base of the lingual wall molar, with a short paraconid and the mesial cristid distally is somewhat broken; whether a basal cingulum existed is inclined. High and very robust protoconid. Metaconid quite not evident. The paracone is robust and large, the metacone reduced, slightly displaced distally and with a somewhat is low and somewhat smaller. Buccal styles scarcely swollen buccal wall. Short talonid, almost completely developed. The large pyramidal protocone does not reveal occupied by the hypoconid whose buccal base is somewhat the presence of a paraconule, but a rather large metaconule widened apically. Entoconid low and elongated and joined can be observed. Cingulum buccal very strong. to the distal hypoconid cristid. Weak basal cingulum. NM-Pv 11705, left M2 (Text-fig. 5c). Molar quite NM-Pv 11711, left m1 (Text-fig. 6d1–3) more slender but wide, but narrow. Paracone very pronounced in relation to with similar morphology to that described above. NM- the metacone, which is somewhat displaced lingually. The Pv 11712, left m1–m2, the m1 is somewhat smaller than protocone and the lingual cingulum are well developed. the other carnassial teeth; the associated m2 is similar to the NM-Pv 11706, left M3 (Text-fig. 5d), compared to the morphotype of NM-Pv 11713 described below. previous molar it is smaller, but the height and strength NM-Pv 11747, left m1–m3 (Text-fig. 6e1–3); slightly of its buccal cones rule out any possible interpretation as smaller size compared to the rest of the specimens attributed an M3, although there is a strong constriction in the distal to this species, m1 very robust, with a short paraconid, wall, which is similar to that observed in the specimen NM- and a mesial cristid distally inclined. High and very robust Pv 11707, which is considered as an M3. protoconid. Metaconid still strong. Short talonid, almost 136 a1 a2 a3 c1 c3 c2 b1 b2 b3 e1 d1 d3 d2 e2 f1 f2 f3 e3 g2 g3 h2 g1 h1 h3 h4 i j1 j2 0 1 2 cm k1 k2 k3 Text-fig. 6. Megamphicyon carnutense (Antunes et Ginsburg, 1977), from Tuchořice, the Czech Republic, lower teeth. a: NM- Pv 11708, left p4, a1 – occlusal view, a2 – buccal view, a3 – lingual view; b: NM-Pv 11709, left p4, b1 – occlusal view, b2 – buccal view, b3 – lingual view; c: NM-Pv 11710, left m1, c1 – lingual view, c2 – occlusal view, c3 – buccal view; d: NM-Pv 11711,­left m1, d1 – lingual view, d2 – occlusal view, d3 – buccal view; e: NM-Pv 11747, left m1–m3, e1 – occlusal view, e2 – lingual view, e3 – buccal view; f: NM-Pv 11713, left m2, f1 – lingual view, f2 – occlusal view, f3 – buccal view; g: NM-Pv 11714, left m2, g1 – lingual view, g2 – occlusal view, g3 – buccal view; h: NM-Pv 11718, right m2, h1 – lingual view, h2 – occlusal view, h3 – buccal view, h4 – distal view; i: NM-Pv 11716, left m2 in occlusal view; j: NM-Pv 11717, left m2, j1 – occlusal view, j2 – buccal view; k: NM- Pv 11696, right m2–m3, k1 – lingual view, k2 – buccal view, k3 – occlusal view. completely occupied by the hypoconid, entoconid low and respect to m1, trigonid with high protoconid somewhat larger elongated and joined to the distal hypoconid cristid. The than the metaconid, small mesiocentral paraconid. Talonid buccal basal wall is broken. The m2 is relatively large with large with strong hypoconid attached to a peripherical 137 entoconid. The m3 is well developed with a dominant d’Anjou). However, Ginsburg et al. (2000) subsequently protoconid, and vestigial metaconid and hypoconid. The reconsidered the taxonomic attribution of the Chilleurs talonid is robust. mandible (type of Amphicyon giganteus carnutense), NM-Pv 11713, left m2 (Text-fig. 6f1–3). It has a relatively considering the determination by Kuss to be correct (1965). high trigonid, dominated by the protoconid, although the Hence, the validity of Amphicyon giganteus carnutense metaconid is also quite well developed. The protoconid was discarded. Therefore, the materials from Les Beilleaux base is buccally widened. Very small paraconid, poorly attributed by Ginsburg (1989) to this taxon remained differentiated from the anterior cristids of the protoconid unnamed, and he proposed the new species Amphicyon and metaconid, which are joined together, closing mesially (Megamphicyon) lathanicus for this fossil considering the trigonid valley. Talonid wide, with a high buccal Megamphicyon Kuss, 1965 as a valid subgenus. hypoconid, clearly separated from the protoconid. The Nonetheless, we recognised many problems in the crestiform entoconid, low and peripheral, is joined distally use of the denomination of Pseudocyon sansaniensis for to the distal hypoconid cristid, thus strongly delimiting the the mandible from Chilleurs (Kuss 1965: fig. 77). The talonid valley, which is flat and very wide. Moderate basal Chilleurs species possesses a more robust m1 than that of the cingulum, only strong in the mesiobuccal area. Another two mandible type of P. sansaniensis (Ginsburg 1961) but above m2, NM-Pv 11714 (Text-fig. 6g1–3) and NM-Pv 11712, all, it presents a significantly larger m2 relative to m1, in display a similar morphology. NM-Pv 11718, right m2 contrast with the small size of the m2 of the Sansan species. (Text-fig. 6h1–4), NM-Pv 11716, left m2 (Text-fig. 6i) and Thus, the decision of Antunes and Ginsburg (1977) remains Pv 11717, left m2 (Text-fig. 6j1–2) present a morphological valid; that the Chilleurs form and Amphicyon olisiponensis pattern somewhat different from that of the teeth described are very similar. Likewise, Ginsburg (1989) considered above, in particular as a result of the narrow form of the that A. olisiponensis could belong to the same group as talonid, which seems relatively more reduced. Amphicyon giganteus. We think that the least confusing NM-Pv 11696, is an association of a right m2 and m3 taxonomic hypothesis is that of Antunes and Ginsburg (Text-fig. 6k1–3). The m2 has a slightly better-developed (1977), considering that the large Chilleurs form determined paraconid than in the previously described specimens. The by Kuss (1965) as Pseudocyon sansaniensis should be mesial wear facet with the m1 talonid is very clear. The called Megamphicyon carnutense, whilst Amphicyon m3 is oval in shape with a strong mesiobuccal protoconid, (Megamphicyon) lathanicus should currently be considered from which a mesial cristid extends to the lingual position, as a synonym for the previous species, an opinion already marking a small cuspid (paraconid). The talonid is poorly expressed by Jiangzuo et al. (2019). differentiated from the trigonid, and the hypoconid is very The dentition from Tuchořice is similar to that of low and extends into a peripheral cristid that completely Megamphicyon carnutense, but some teeth manifest surrounds the talonid. morphological variations that may suggest the presence of a second species; as is the case of three m2 (specimens NM- D i s c u s s i o n . Megamphicyon carnutense was defined Pv 11718, NM-Pv 11716 and NM-Pv 11717), which possess by Antunes and Ginsburg (1977) as a new subspecies a narrow talonid, and are slightly smaller than the specimens Amphicyon giganteus carnutense, in the same paper where with a subquadrate talonid. However, similar differences they defined a new species Amphicyon olisiponensis, from are found in the m2 of the Falun d’Anjou described as the locality of Quinta do Narigao, Lisbon Basin, Portugal. Amphicyon lathanicus by Ginsburg (2000b), in which According to these authors, Amphicyon olisiponensis appears morphotypes with a wide and subquadrate talonid (m2, FS to show affinities with both the mandible classified by Kuss 6953) coexist with others possessing a narrower talonid (1965) as Pseudocyon sansaniensis aff. sansaniensis from (FS 6965). We therefore regard all described specimens as Chilleurs, France, and the primitive forms of Amphicyon belonging to a single species, Megamphicyon carnutense. giganteus. Antunes and Ginsburg (1977) highlighted the difficulties involved in distinguishing between the Chilleurs Tribe Pseudarctini nov. form and Amphicyon olisiponensis. However, the small morphological differences between these two forms, T y p e g e n u s . Pseudarctos Schlosser, 1899. together with the more modern age of the Lisbon site, lead D i a g n o s i s . As in the Amphicyonini tribe, the molars them to maintain a specific distinction between the two. tend to present a larger crushing surface, albeit displaying Therefore, according to these authors the Chilleurs form a different pattern with a greater mesiodistal length of the should be classified as Amphicyon giganteus, but differences upper molars and buccolingual length in the lower molars, in size lead them to propose a new subspecies A. giganteus associated with a significant reduction of the carnassial carnutense. teeth, and loss of the p4 distal accessory cuspid. Dehmicyon Ginsburg (1989) added a third subspecies, Amphicyon n. gen. is included as a basal form of this tribe. giganteus laugnacensis, to distinguish the maxilla from Laugnac, determined by de Bonis (1973) as Amphicyon cf. I n c l u d e d g e n e r a . Pseudarctos Schlosser, 1899, Ictiocyon Crusafont, Villalta et Truyols, 1955 and astrei Kuss, 1962 from the other subspecies. He concluded Dehmicyon n. gen. that the Amphicyon giganteus species would comprise three successive stratigraphic subspecies; Amphicyon giganteus Genus Dehmicyon n. gen. laugnacensis: MN 2; Amphicyon giganteus carnutense: MN 3; Amphicyon giganteus giganteus: MN 4a (Artenay), T y p e s p e c i e s . Amphicyon schlosseri Dehm, 1950 MN 4b (Baigneaux-en-Beauce), MN 5 (Pontlevoy, Falun (Wintershof- West, Germany; early Miocene, MN 3). 138 a1 0 1 2 cm a3 a2 b 0 1 2 cm c d Text-fig. 7. Dehmicyon n. gen. schlosseri (Dehm, 1950), from Wintershof-West, Germany. a: BSP 13562, mandible (holotype), a1 – right hemimandible in buccal view, a2 – occlusal view, a3 – left p4–m2 in occlusal view; b: BSP 12365, left maxilla fragment with M1 in occlusal view; c: BSP 13562, left maxilla fragment with P3 broken, P4–M2 and M3 alveolus (holotype) in occlusal view; d: BSP 12343 left maxilla fragment with P4, alveolus for M1, M2 and M3 alveolus in occlusal view. E t y m o l o g y . In honour of Dr. Richard Dehm. T y p e l o c a l i t y . Wintershof-West, Germany. D i a g n o s i s . Pseudarctini with robust mandible, A g e . Early Miocene, MN 3. small mesial premolars (p1–p3), p4 unicuspidated. High m1 E m e n d e d d i a g n o s i s . Same as genus. trigonid with strong metaconid; short and narrow talonid. m2 remaining long compared with m1. P4 robust with R e m a r k s . Dehmicyon schlosseri presents an strong protocone. Slender M1 with subtriangular occlusal interesting combination of morphological features, which shape. M2 small compared to M1. enable it to be differentiated from Cynelos lemanensis (Pomel, 1846) and from the Ictiocyon-Pseudarctos group. Dehmicyon schlosseri (Dehm, 1950) Their separation from C. lemanensis and related species is Text-figs 7, 8 unequivocal, as evidenced by Peigné and Heizmann (2003), in particular due to the poor development of the crushing 1950 Amphicyon schlosseri n. sp.; Dehm, p. 20, figs 9–17. 1965 Cynelos rugosidens schlosseri (Dehm) 1950; Kuss, p. 63– molars, which suggests a more primitive morphological 66. stage than the Cynelos-Amphicyon group species, typical 1981 ?Cynelos schlosseri (Dehm), 1951; Ginsburg et al., p. 185, representatives of the Amphicyoninae clade. Together with fig. 2. the Ictiocyon-Pseudarctos group, it shares the robustness 1989 Cynelos schlosseri; Ginsburg, p. 107. of the jaw and the morphology of the lower p4 lacking 1996 Cynelos schlosseri (Dehm, 1950); Viranta, p. 22, fig. 7. a distal accessory cuspid (residual in some specimens). 1999 Cynelos schlosseri (Dehm, 1950); Ginsburg, p. 116. Other morphological characters that it shares, in particular 2003 Cynelos schlosseri; Peigné and Heizmann, p. 14. with Ictiocyon, involve the strong development of the buccal 2008 C[ynelos] schlosseri; Peigné et al., p. 954. wall of the M1 in relation to the lingual area, the large size 2015 Cynelos schlosseri; Hunt and Stepleton, p. 4 of the buccal cingulum and the robust development of the H o l o t y p e . BSP 1937 II 13562, mandible and maxilla styles. However, in Ictiocyon the M1 is wide, especially (Dehm 1950: figs 9–11). See Kuss (1965: 63). on its occlusal surface, similar to that of the other molars 139 a b c Text-fig. 8. Bivariate diagram of length and width of the lower dentition (m1 and m2) of Pseudarctos, Ictiocyon and Dehmicyon species. a: m2; b: m1; c: length m1 and m2. Data from Schlosser (1904), Helbing (1937), Thenius (1949), Dehm (1950), Crusafont et al. (1950), Ginsburg (1992). Abbreviations: L – length; W – width; Ba – Baigneaux; LRM – Pellecahus. 140 (Crusafont et al. 1955). This tendency towards a larger crushing surface in the molar dentition is shared with the Cynelos-Amphicyon group, but in the Ictiocyon-Pseudarctos group the carnassials are significantly reduced (P4/m1), whereas in Cynelos and Amphicyon they tend to show an increase in size. In the latter genus, the upper molars maintain a strong buccal-lingual development, while in Ictiocyon they tend to present a sub-square occlusal shape. a1 Ginsburg (1992) reviewed the species included in Pseudarctos, rejecting the proposal of Kuss (1965) that supported the existence of an anagenetic line formed by a single species Pseudarctos bavaricus with different a2 a3 temporal subespecies. The French author, proposing the existence of two genera; Ictiocyon Crusafont, Villalta et Truyols, 1955 new rank and Pseudarctos Schlosser, 1899, but without accepting the validity of Ictiocyon dehmi the type species of Ictiocyon, which he considered as synonymous with Ictiocyon socialis. However, Ictiocyon dehmi shows b more derived characteristics than Ictiocyon socialis. This is a4 seen especially in the greater robustness of the premolars and 0 5 10 mm the morphology of the m1–m2 talonid, which are wider and more developed than the trigonid. This tendency to increase Text-fig. 9. Dehmicyon aff. schlosseri (Dehm, 1950), from the surface of the talonid relative to the trigonid became Tuchořice, the Czech Republic. a: NM-Pv 11675, right M1, a significant feature in Pseudarctos. The morphology of m1 a1 – buccal view, a2 – mesial view, a3 – distal view, a4 – occlusal suggest that the mandible of Wintersoft-West BSP 1937 II view; b: NM-Pv 11676, right M2 in occlusal view. 12301 determined as Ictiocyon socialis by Dehm (1950) could be closer to Ictiocyon dehmi than to I. socialis, so we suggest it be reclassified as Ictiocyon cf. dehmi. buccal cingulum. Paracone and metacone subequal in size. Dehmicyon can be interpreted as a similar form to Strong pyramidal protocone, surrounded by a prominent Ictiocyon genus with which it appears to share derived cingulum that reaches the bases of both the paracone and characters such as mandibular robustness and loss of the the metacone. Reduced paraconule and metaconule, almost posterior accessory cuspid on the p4; other features shared completely included in the cingulum. by both groups can be considered as primitive; e.g., the NM-Pv 11676, right M2 (Text-fig. 9b). Small size strong development of the styles and the buccal cingulum compared with the M1. Developed parastylar area. Medium- and the narrow morphology of the lingual area of the M1 or sized parastyle and metastyle. Weak buccal cingulum. the small size of the second and third molars. Unfortunately, Metacone much smaller than the paracone. Protocone in the absence of upper dentition in Ictiocyon socialis prevents central position which, together with the paraconule and direct comparison with the new genus. However, the the metaconule, form a semicircle. Strong, wide lingual morphology of the lower dentition supports the proposal that cingulum. D. schlosseri is closer to I. socialis than I. dehmi. D i s c u s s i o n . The size of these two molars is similar to D. schlosseri has simultaneously a less specialized that of the homologous teeth of Dehmicyon schlosseri from dental morphology than I. socialis (in particular seen in the Wintershof-West described by Dehm (1950) (Text-fig. 7). reduced robustness of the m1) and greater size of the m2 Features shared with this species: 1) the greater buccal length with compared to the m1 (Text-fig. 8). These differences are with respect to the lingual length; 2) the strong development sufficiently important to separate both species at a generic of the buccal cingulum and the buccal styles; 3) the similar level. Dehmicyon schlosseri can be interpreted as a basal paracone-metacone size ratio in the M1; 4) the small size form of Pseudarctini, already far removed from the primitive of the M2 compared with the M1. Some of these characters Amphicyonini represented by Cynelos species. were already pointed out by Peigné and Heizmann (2003) as Dehmicyon aff. schlosseri (Dehm, 1950) being typical of D. schlosseri. However, in the morphology Text-figs 1, 9, Tab. 1c of the M1 from Tuchořice there are some differences in relation to this species; in particular, the greater development L o c a l i t y . Tuchořice, the Czech Republic. of the buccal cingulum and the mestastyle are striking; the A g e . Early Miocene, MN 3. protocone is placed in a central position, it is robust and surrounded by a very prominent cingulum which reaches S t u d i e d m a t e r i a l . NM-Pv 11675 (TU 738922), the bases of the paracone and metacone, and in which the right M1; NM-Pv 11676 (TU 738923), right M2. very reduced paraconule and metaconule are included. The D e s c r i p t i o n . NM-Pv 11675, right M1 (Text-fig. differences in the morphology of the M2 are minor. Taking 9a1–4). Molar with elongated buccal wall and narrow lingual into account the highly variable dental morphology of most wall. Well-developed metastyle, separated by a notch from of the amphicyonid species, we classify these two molars the mesial crista of the metacone. Strong parastyle. Large from Tuchořice as Dehmicyon aff. schlosseri. 141 Tribe Magericyonini nov. Additionally, the present research received support from the SYNTHESYS Project http://www.synthesys.info/, T y p e g e n u s . Magericyon Peigne, Salesa, Anton et funded by a European Community Research Infrastructure Morales, 2008 Action within the FP7 “Capacities” Program under the grant D i a g n o s i s . Amphicyoninae with hypercarnivorous agreement (SYNTHESYS; CZ-TAF-3329) of J.A. O.F. and dentition; premolars strongly reduced; metaconid reduced J.W. were granted funding by the Ministry of Culture of or absent in m1 and m2; robust P4; M1 with high buccal the Czech Republic (DKRVO 2019–2023/2.V.c, National cusps; M2⁄m2 reduced relative to M1⁄ m1, M3/m3 vestigial. Museum, 00023272). We also thank Dr. Serdar Mayda and Dr. Michael Morlo for helpful reviews of the manuscript. I n c l u d e d g e n e r a . Magericyon Peigne, Salesa, Anton et Morales, 2008 and ?Pseudocyon Lartet, 1851 References R e m a r k s . Two species are recognized within genus Magericyon – M. anceps Peigné, Salesa, Antón et Morales, Antunes, M. T., Ginsburg, L. (1977): Notes sur la géologie 2008 and M. castellanus (Ginsburg, Morales et Soria, et la paléontologie du Miocène de Lisbonne XIX – sur 1981). Genus Pseudocyon is assigned to this tribe with some un Amphicyon (Mammalia, Ursidae) du Burdigalien. – doubt. Comunicações dos Serviços Geológicos de Portugal, 61: 335–342. Blainville, H.-M. D. de (1841): Ostéographie ou description Conclusions iconographique comparée du squelette et du système The early Miocene (MN 3) Amphicyonidae of Tuchořice dentaire des cinq classes d’animaux vertébrés récents et fossiles pour servir de base à la zoologie et à la géolo- (the Czech Republic) are represented by two subfamilies; gie – Mammifères carnassiers: Des Petits-Ours (G. Sub- Thaumastocyoninae Hürzeler, 1940, which contains a ursus). – J. B. Baillière, Paris, 123 p. unique species Peignecyon felinoides (see Morales et al. Bonis, L. de (1973): Contribution a l’étude des Mammiféres 2019), and Amphicyoninae Trouessart, 1885, with three de l’Aquitanien de l’Agenais: Rongeurs-Carnivores-Pe- species. rissodactyles. – Mémoires du Museum National d’His- The two more abundant species belong to the genera toire Naturelle, 28:1–192. included in the tribe Amphicyonini; Paludocyon n. gen. Bowdich, T. E. (1821): An Analysis of the Natural Classifi- and Megamphicyon Kuss, 1965. Paludocyon bohemicus cations of Mammalia, for the Use of Students and Trav- (Schlosser, 1899) from Tuchořice was originally determined ellers. – J. Smith, Paris, 115 pp. as Pseudocyon bohemicus by Schlosser (1899). Paludocyon Crusafont, M., Villalta, J. F., Truyols, J. (1955): El Burdi- could have diverged from Cynelos, maintaining smaller galiense continental de la cuenca del Vallés-Penedés crushing molars and modifying the remaining dentition. [The continental Burdilagian of the Vallés-Penedés ba- Ginsburg (1999) proposed a close relationship between sin]. – Diputación Provincial de Barcelona. – Memorias Paludocyon bohemicus and Heizmannocyon steinheimensis, y Comunicaciones del Instituto Geológico, 12: 7–273. including both species in Heizmannocyon. Whatever the case (in Spanish) may be, the dental morphological differences between these Dehm, R. 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