Eliomys yevesi, Mansino & García-Alix & Ruiz-Sánchez & Montoya, 2015

Mansino, Samuel, García-Alix, Antonio, Ruiz-Sánchez, Francisco J. & Montoya, Plinio, 2015, A new Eliomys from the Late Miocene of Spain and its implications for the phylogeny of the genus, Acta Palaeontologica Polonica 60 (3), pp. 577-588 : 579-582

Eliomys yevesi sp. nov.

Fig. 2A–L .

1953 Eliomys aff. intermedius ; Friant 1953: pl. 4: 9–19. 2008 Eliomys aff. intermedius ; García-Alix et al. 2008a: 24–25.

Etymology: Dedicated to José María Yeves and his family, owners of the “Hostal Ventamorino”, for their friendly hospitality during the many summer campaigns in Venta del Moro.

Holotype: Right M1, VVmA-25.

Type locality: Venta del Moro A, Cabriel Basin, Spain; coordinates: 39º 28’ 29.12’’ N, 1º 20’ 40.38’’ W .

Type horizon: Villatoya-Venta del Moro Formation, MN13, late Turolian (Late Miocene, 6.23 Ma).

Material.—Venta del Moro: 2 p4 (VVmA-42, 43), 12 m 1, m2 (VVmA-1–11, 32), 6 m 3 (VVmA-33–38), 1 dP4 (VVmA- 44), 3 P4 (VVmA-39–41), 12 M1, M2 (VVmA-16, 21–31), 8 M3 (VVmA-12–15, 17–20); 1 m 1, m2 (VVmB-1). VVmBC: 2 m 1, m2 (VVmBC-1, 2), 1 m 3 (VVmBC-5), 1 M1, M2 (VVmBC-3), 1 M3 (VVmBC-4); 1 m 3 (VVmC-1); 2 M1, M2 (VVmD-1, 2). Alcoi Barranc Sud 3A, MN14: 1 m 1, m2 (ABS3A-38).Alcoi Forn, MN13-MN14: 1 m 1, m2 (AF1’06- 190), 1 m 3 (AF1’06-187); 1 M1, M2 (AF1’07-36). Purcal 4, MN14: 1 p4 (PUR-4 871), 12 m 1, m2 (PUR-4 872–883), 3 m 3 (PUR-4 884–886), 1 dP4 (PUR-4 887), 1 P4 (PUR-4 888), 2 M1, M2 (PUR-4 889, 890), 3 M3 (PUR-4 891–893). Calicasas 3B, MN14: 1 m 3 (CLC-3B 67), 2 M1, M2 (CLC- 3B 68, 69), 1 M3 (CLC-3B 70).

Diagnosis.— Size intermediate between Eliomys truci and the youngest E. intermedius ; sub-quadrangular m1, m2, usually with a posterotropid and a well-developed centrolophid; no posterotropid on m3; common presence of both centrolophs in the upper molars; posteroloph and endoloph usually connected.

Differential diagnosis.— Eliomys yevesi differs from E. assimilis in the more quadrangular shape of m1, m2, less reduced m3, and the absence of any accessory crests in the upper molars; from E. reductus in its bigger size, more quadrangular shape of the lower molars, discontinuous endolophid, and common presence of posterotropid; and from E. lafarguei in its bigger size, long centrolophid on m1, m2, discontinuous endolophid, the presence of a centrolophid on many m3, and the common presence of postcentrolophs in the upper molars.

Eliomys yevesi ranges in size from the biggest specimens of E. truci to the smallest ones of E. intermedius . It differs from E. truci in more frequently showing centrolophs in the upper molars, as well as the presence of well-developed postcentrolophs, reaching half the width of the tooth or more, in some specimens ( Fig. 2G ). E. yevesi further differs from E. intermedius in the subquadrangular shape ( Fig. 2B, C, N, R ) and lower and narrower lingual wall of the upper molars ( Fig. 2F, G ). A long centrolophid connected to the metalophid is present in all but one m1, m2 of E. yevesi , whereas in E. intermedius it is short in 27 out of 106 specimens. In addition, the posterotropid is more frequent and usually longer in E. yevesi than in E. intermedius (27 out of 29 m 1, m2 of E. yevesi ; 80 out of 107 of E. intermedius ). In the upper molars, the two centrolophs are usually slightly longer and occur somewhat more frequently in E. intermedius (97 out of 165, 58.78%, compared to 17 out of 36, 47.22%, in E. yevesi ).

Eliomys yevesi differs from the extant E. quercinus in its smaller size, but resembles the latter in the absence of accessory crests in the upper molars and an anteroloph-protoloph connection, as well as the frequent presence of two centrolophs. Two subspecies of E. quercinus with distinct m1, m2 morphologies occur in the Iberian Peninsula: E. q. lusitanicus, which differs from E. yevesi in the absence of a centrolophid; and E. q. quercinus , which differs from E. yevesi in the absence of accessory crests in the lower molars, a continuous endolophid on m1, m2 and in having a small centrolophid.

Measurements. —See Table 2.

Description.— Material from Venta del Moro: p4: The occlusal outline of this tooth is subtriangular. The protoconid and the large anterolophid create a high, triangular anterior complex, which is separated from the metaconid by a narrow furrow. One specimen (VVmA-42; Fig. 2A ) has a short centrolophid. The mesoconid and entoconid are connected by the mesolophid, and separated from the anterior complex by deep valley. The mesoconid and hypoconid are separated. There is no posterotropid. The posterolophid is high and curved. There are two fused roots.

m1, m2: The occlusal outlines of these teeth are sub-quadrangular. The anterolophid is connected to the protoconid in 6 out of 14 specimens (4 out of 12 from VVm-A, the only specimen from VVm-B and 1 out of 2 from VVm-BC). One specimen ( Fig. 2C ) has a vestigial anterotropid. Most molars show a connection between the metalophid and the metaconid, whereas the metaconid and entoconid are separated. The centrolophid is usually long and sometimes connected to the metalophid. The posterotropid is long in 10 specimens (9 out of 12 from VVm-A, 1 out of 2 from VVm-BC), short in three one specimen from VVm-A, the only specimen from VVm-B and 1 of 2 from VVm-BC) and absent in another two (both from VVm-A). The hypoconid is large. There are three roots.

m3: The occlusal outline of this tooth is sub-trapezoidal. The anterolophid is usually separated from the protoconid. The metalophid is sometimes connected to the metaconid. There are no accessory crests. Where present, the centrolophid is not connected to the metalophid. In 1 out of 13 m 3, the mesolophid does not reach the entoconid ( Fig. 2D ). The posterolophid is continuous.

dP4: Known only from a single, extremely worn molar. No features of the occlusal surface can be observed.

P4: The occlusal outline of this tooth is triangular. The paracone and metacone are higher than the protocone. The anteroloph is short, low and connected, at a low level, to the paracone. The protoloph is clearly discontinuous in 1 out of 4 specimens, whereas the remainder shows just a constriction in the central part of this crest. Two specimens present a well-developed precentroloph, and a further one a postcentroloph, which is not connected to the metacone ( Fig. 2E ). The metaloph is high and continuous. The posteroloph is low and lingually connected to the protocone; discontinuous in two specimens, and not connected to the endoloph in another one ( Fig. 2E ). The roots are not preserved in any of the specimens.

M1, M2: The occlusal outlines of these teeth are trapezoidal or subrectangular. The anteroloph is separated from the paracone and the protoloph. The paracone and metacone are high and separated. The protoloph and metaloph are continuous, and occasionally sinuous. There is a well-developed precentroloph, which is not connected to the paracone in one of the specimens and reaches the metaloph in another one. Where present, the postcentroloph is short, except in VVmA- 29, which has a well-developed crest, and VVmA-25, in which both centrolophs are fused into a central crest ( Fig. 2G ). The posteroloph is connected to the endoloph. There are three roots.

M3: The occlusal outline of this tooth is trapezoidal. The anteroloph is connected to the protocone. In some specimens, the protoloph and metaloph are sinuous. Both centrolophs are present in 5 out of 8 specimens from VVm-A, and the single tooth from VVm-BC. Two of the specimens from VVm-A bear a long postcentroloph ( Fig. 2H ). Where present, the precentroloph is usually attached to the paracone, whereas the postcentroloph is connected to the metacone. The endoloph is continuous, except for the single specimen from VVm-BC. There are three roots.

Material from Alcoy: These specimens from the Alcoy Basin resemble the specimens from Venta del Moro, with the exception of having an anterolophid connected basally with the protoconid, and a metalophid that does not reach the metaconid (both on m1, m2). In the m1, m2 from ABS-3A Fig. 2J ), the centrolophid is not continuous. In the M1, M2 from AF-1’07 ( Fig. 2L ), the anteroloph and the paracone are connected basally.

Remarks.— Eliomys yevesi is a relatively small-sized species, being smaller than Plio-Pleistocene E. intermedius and E. quercinus , and only slightly larger than the Miocene representatives of the genus ( E. lafarguei , E. reductus , and E. assimilis ) ( Fig. 3 ). The molars from Venta del Moro and AF- ’07 fall within the range of variation of E. truci . However, the specimens from the early Ruscinian localities of PUR-4 and CLC-3B ( Granada Basin), and AF-1’06 and ABS-3A Alcoy Basin), are slightly larger, and intermediate between E. truci and E. intermedius ( Fig. 3 ).

Morphologically, the present material resembles E. truci , but differs in the development of the centrolophs on M1, M2, while the presence of both centrolophs is rare in E. truci (5 out of a total of 41 specimens, 12.90%; two specimens from Concud 3 and one each from OTU-1, PUR-23, and Orrios 3), 4 out of 12 specimens E. yevesi from VVm-A and VVm-BC 33.33%), and all of the M1, M2 from VVm-D, AF-1’07, CLC-3B, and PUR-4 (except one) have both centrolophs. Moreover, when present, the postcentroloph is usually reduced in E. truci , whereas in some M1, M2 of E. yevesi from VVm-A it is very well developed, reaching half the width of the molar or more ( Fig. 2G ). Similarly, E. truci never bears two centrolophs on M3, whereas they do occur in 5 out of 8 molars (62.50%) of E. yevesi from VVm-A, as well as the only M3 from VVm-C and CLC-3B.

In the upper molars of E. intermedius , 79 out of 130 60.77%) M1, M2 and 18 out of 35 (51.42%) M3 have two centrolophs ( Weerd 1976; Adrover 1986; Castillo 1990; García-Alix et al. 2008a). Specimens from both the extant Castillo 1990) and relatively young fossil (e.g., Casablanca B; García-Alix et al. 2008a) populations of E. quercinus generally have two centrolophs, with the anterior one often being longer. Together, these observations support a trend towards better-developed centrolophs within a lineage comprising E. truci – E. yevesi – E. intermedius – E. quercinus .

Besides the change in development of the centrolophs, Eliomys also shows a trend towards the reduction of the centrolophid and the accessory crests in the lower molars Castillo 1990; García-Alix et al. 2008a). This observation is borne out by the present data, m1, m2 of E. yevesi resemble those of E. truci in having a long centrolophid and a well-developed posterotropid. In E. intermedius , the centrolophid is still present in 104 out of 106 (98.11%) m1, m2, but in 26 of these specimens (24.53%) it is less than half the width of the molar—with the exception of the material from Sète (n = 30), which always displays a long centrolophid. The centrolophid is even more reduced in E. quercinus , where it is short in 8 (61.54%) and absent in 5 (38.46%) out of the 13 studied specimens. A posterotropid is present in 29 out of 30 m 1, m2 of E. truci (96.67%), 27 out of 29 m 1, m2 of E. yevesi (93.10%), 80 out of 107 m 1, m2 of E. intermedius (74.76%), and 1 out of 11 m 1, m2 (9.09%) of E. quercinus (2 of the 13 specimens studied here are too damaged or worn to observe this character).

Stratigraphic and geographic range.— MN13–14, Late Miocene–Early Pliocene; Cabriel, Granada, and Alcoy basins of southeastern Spain.

Figures

Fig. 2. The glirid mammals Eliomys yevesi sp. nov. (A–L) and Eliomys intermedius Friant, 1953 (M–U) from Spain, Villatoya-Venta del Moro Formation, Miocene (see Table 1 for locality name abbreviations). A. VVmA-42 (MGUV-27256), right p4. B. VVmA-1 (MGUV-27215), right m1, m2. C. VVmA- 6 (MGUV-27220), right m1, m2. D. VVmBC-5 (MGUV-27490), right m3. E. VVmA-40 (MGUV-27254), left P4. F. VVmA-16 (MGUV-27230), right M1, M2. G. VVmA-25 (MGUV-27239), right M1, M2. H. VVmA-13 (MGUV-27227), left M3. I. VVmA-14 (MGUV-27228), left M3. J. ABS3A-38 (MGUV-23529), right m1, m2. K. AF1’06-190 (MGUV-28334), right m1, m2. L. AF1’07-36 (MGUV-28427), left M1, M2. M. AC0-88 (MGUV-28551), right m3. N. LB2B-176 (MGUV-28727), right m1, m2. O. LB2B-241 (MGUV-28727), left M1, M2. P. LB2B-177 (MGUV-28728), left M3. Q. LB2B- 178 (MGUV-28729), left P4. R. AL2D-290 (MGUV-28063), left m1, m2. S. AL2D-356 (MGUV-28129), left m3. T. AL2D-291 (MGUV-28064), right M1, M2. U. AL2D-293 (MGUV-28066), left M1, M2.

Fig. 3. Comparison of length and width measurements (in mm) of p4 (A), P4 (B), m1, m2 (C), M1, M2 (D), m3 (E), and M3 (F) of Eliomys truci from Aljezar B, Hautimagne, Los Mansuetos, Orrios, Sarrión, Sete, Villalba Alta (Adrover 1986), Concud 2 and 3, Concud Barranco de los Calaveros, Los Mansuetos, Masada del Valle 2, 5 and 7, Tortojada A and C (Weerd 1976), DHS-1 and 16, PUR-23, 24, and 25A, OTU-1, TCH-1B and 13 (García-Alix et al. 2008a), Negratín-1 (Minwer-Barakat et al. 2009); Moreda 1A, 1B, Rambla Seca 1 (Castillo 1990) and Puente Minero (Alcalá et al. 1991); Eliomys yevesi sp. nov. from VVm-A, B, BC, C, and D, ABS-3A, AF-1’06, AF-1’07, CLC-3B, and PUR-4; Eliomys intermedius from Arquillo 3, Sete, Orrios 3, Villalba Alta (Adrover 1986), Escorihuela, Orrios (Weerd 1976), PUR-13, TCH-1 and 1B, TCH3, TCH-13 (García-Alix et al. 2008), Moreda 1A, 1B, Bélmez 1 and Rambla Seca A1 and A2 (Castillo 1990) and Alozaina (Aguilar et al. 1993); Eliomys quercinus from Vallparadís and Cal Guardiola (Minwer-Barakat et al. 2011, Baños de Mula (Agustí et al. 1990), Peña de Estebanvela (Sesé 2006b), Valdocarros (Sesé et al. 2011), Sima de los Huesos (Cuenca-Bescós et al. 1997), Bois Roche (Sesé and Villa 2008), Santenay (Chaline 1972); and Eliomys aff. quercinus from Huétor Tájar 1 and 8.