Simplomys simplicidens ( De Bruijn, 1966 )
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publication ID |
https://doi.org/ 10.5252/geodiversitas2023v45a20 |
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publication LSID |
urn:lsid:zoobank.org:pub:A8246B9C-1181-4074-B8EC-4746C75C6578 |
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DOI |
https://doi.org/10.5281/zenodo.10166308 |
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persistent identifier |
https://treatment.plazi.org/id/BC4E87DB-FFDC-2E17-7F9B-06428F3DF1F1 |
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treatment provided by |
Plazi |
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scientific name |
Simplomys simplicidens ( De Bruijn, 1966 ) |
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Simplomys simplicidens ( De Bruijn, 1966)
( Fig. 8 View FIG )
LOCALITIES. — MCX3, MCX4, MCX5, MCX6, MTR2, MTR3, BC1, BC2, MAB0A, MAB0B, MAB3, MAB5, MAB11, CBR0B, and CBR1.
MATERIAL. — MCX3: 1 m1, 3 m2, 1 m3, 2 M1, 2 M2, 4 M3; MCX4 : 1 M1, 1 M2 ; MCX5 : 1 M2 ; MCX6 : 1 m1 ; MTR2 : 1 m2, 1 P4, 1 M1, 2 M2 ; MTR3 : 1 M1/M2 ; BC1: 1 p4, 5 m1, 4 m2, 3 m3, 1 P4, 3 M1, 6 M2, 3 M3; BC2: 1 m2; MAB 0A: 3 m1, 1 m2 ; MAB 0B: 1 m1, 1 m2, 1 M3 ; MAB3 : 1 d4, 5 p4, 7 m1, 3 m2, 4 m3, 5 P4, 2 M1, 1 M2, 1 M3 ; MAB5 : 5 p4, 2 m1, 3 m2, 5 m3, 3 P4, 5 M1, 3 M2, 2 M3 ; MAB11 : 1 D4, 1 M2, 1 M3 ; CBR 0B: 1 m2, 1 M2, 1 M3 ; CBR1 : 1 m1, 1 m2, 2 m3, 1 M1 .
MEASUREMENTS. — Appendix 11
DESCRIPTION
d4 (MAB3)
The outline is subtriangular. The anterolophid is long and attached to the sinusoid metalophid on the lingual side and attached to a sinusoid posterolophid on the labial side.
p4 ( MAB 3)
Tooth hypsodont and subtriangular in shape.The anterolophid may be short (3 out of 5) or absent (2 out of 5). The metalophid may be a posterior spur of the anterolophid (2 out of 5), short and attached to the anterolophid (1 out of 5) or long (2 out of 5). The mesolophid may be absent (2 out of 5), if present it may be long and irregular (1 out of 5), short (1 out of 5), or a spur of the metalophid (1 of 5). The mesolophid is connected to a well-developed posterolophid. There is only one root. The specimens found in BC1 fit in this description. The specimens from MAB 5 show the following differences: the shape in occlusal view is variable; the metalophid may be absent; in one individual there is a centrolophid; the mesolophid in another specimen has a small crestid that joins with the anterior part of the tooth; in one specimen there is a large labial cuspid which is connected to a short posterolophid; finally, one tooth shows a divided posterolophid.
m1 ( MAB 3)
The outline is sub-rectangular with high crestids. The anterolophid may be short (4 out of 6) or intermediate in size (2 out of 6). The metaconid is connected to the anteroconid. The metalophid is curved and long. The centrolophid may be developed to almost half of the tooth width (5 out of 6) or until the middle of the tooth (1 out of 6). The mesolophid and the posterolophid may be long and connected (1 out of 5) or with a low connection (4 out of 5). In one specimen the mesolophid is almost divided. The labial cuspids are more developed than the lingual cuspids. The posterolophid has a small spur. There are no accessory crestids. The specimens found in CBR 1 are similar to those described above. In MCX3, the mesolophid and the posterolophid are not connected. In MCX6 the centrolophid is slightly longer. In BC1 the centrolophid is shorter and there is one specimen without the mesolophid-posterolophid connection. In MAB 0A, the centrolophid is usually divided and there is one individual without the mesolophid-posterolophid connection. In MAB 0B the mesolophid has a posterior spur. In a specimen from MAB 5 the posterolophid has an anterior spur.
m2 (BC1)
Tooth sub-rectangular with high crestids. The anterolophid is long. The metaconid is connected to the anteroconid. The metalophid is curved and long, in one specimen it does not contact the anteroconid. The centrolophid may be short (3 out of 4) or almost inappreciable (1 out of 4). In one specimen the endolophid is a spur of the centrolophid. The mesolophid and the posterolophid are long and may be well connected (1 out of 3) or weakly connected (2 out of 3). In one specimen the entoconid is poorly developed. The labial cuspids are more developed than the lingual cuspids. The posterior valley is the widest one. No extra crestids. The specimens found in BC2, MAB 0A, MAB 3, CBR 0B and CBR 1 are similar to those just described. In MCX3 one specimen has a posterior spur on the anterolophid and another specimen on the metalophid; in another specimen the centrolophid contacts the metalophid. In MTR2 the anterolophid is shorter. In MAB 0B there is no mesolophid-posterolophid connection. In MAB 5 there is an individual with an isolated metalophid and in another one the mesolophid is divided.
m3 ( MAB 5)
The tooth is slightly reduced and very variable. It is D-shaped and more or less elongated in occlusal view. The anterolophid may be long (4 out of 5) or intermediate in size (1 out of 5). The metalophid is long and curved. The endolophid is short. The centrolophid may be absent (3 out of 5) or barely extend into the valley (2 out of 5). The mesolophid is short and may be connected (1 out of 5) or not (4 out of 5) to the hypoconid. It may be disconnected from both the hypoconid and the posterolophid (3 out of 5), or in contact with the posterolophid either on the labial side (1 out of 5) or in the middle of the tooth (1 out of 5). The posterior valley is well developed, as is the posterolophid. The specimens found in MCX3 follow the previous description. In BC1 the metalophid is straighter and the mesolophid longer. In MAB 3 the mesolophid is also usually longer. In CBR 1 the mesolophid is divided in two.
D4 ( MAB 11)
The tooth is subtriangular in shape. The anteroloph is very short. The protoloph is divided in two and one of the parts is connected to the protocone. Both the metaloph and the posteroloph are long and connected to the protocone.
P4 ( MAB 3)
The outline is sub-rounded. The anteroloph may be long (3 out of 5) or short (2 out of 5) and it may be attached to the protoloph on the labial part (2 out of 5) or isolated (3 out of 5). The protoloph may be better developed than the metaloph (2 out of 5) or both may be well developed (3 out of 5); they may be isolated from each other (2 out of 5) or connected forming a typical Y-shape (3 out of 5). The posteroloph may be long (2 out of 5), medium (3 out of 5) or short (1 out of 5), with a metaloph attached to the middle of the tooth (1 out of 5) or with an isolated posteroloph (4 out of 5). The specimens found in MTR2 and BC1 are similar to those described above. In MAB 5 there are two specimens with a divided protoloph and one with the metaloph divided in three parts.
M1 (BC1)
The tooth is hypsodont and with a square outline. The anteroloph is of intermediate size and isolated lingually. The protoloph and the metaloph form the typical Y, joining near the lingual face. The centrolophs are absent. The posteroloph is isolated and short, in one specimen it is long. The specimens found in MTR3 fit in this description. In MCX3, the protocone and the hypocone are joined by a crest on the lingual side, while the anteroloph has a spur directed towards the protoloph and the metaloph shows another spur directed towards the posteroloph. In MCX4 the metaloph has a small spur on the anterolabial side. In MTR2 the anteroloph is longer. In MAB 3 the anteroloph is long and isolated, the specimens have a postcentroloph which may be long or short and the posteroloph may be connected to the metaloph on the lingual side. In MAB 5 the anteroloph is isolated, while in three specimens the postcentroloph is long. In CBR 1 the postcentroloph is medium in size, the protoloph has a posterior spur and the posteroloph is isolated.
M2 (BC1)
The tooth is hypsodont and square. The anteroloph is long, lingually isolated and labially attached (3 out of 5), or totally isolated (2 out of 5). The protoloph and the metaloph form the typical Y, joining near the lingual side. The centrolophs are absent. The posteroloph may be long and connected at both ends (1 out of 5), or shorter and isolated (4 out of 5). The specimens found in MCX4 and MCX5 are similar to those described. In MCX3 (figure IV.171b) the anteroloph is isolated. In MTR2, the anteroloph is isolated, and the metaloph has a low connection on the Y. At MAB 3 and CBR 0B there is a small crest before the anteroloph, which is isolated. In MAB 5 (figure IV.171d), the anteroloph is isolated, and in two specimens there is a postcentroloph. In MAB 11 (figure IV.171c) the anteroloph is isolated.
M3 (MCX3)
The tooth has a sub-rectangular outline. The anteroloph is long and forms a closed ellipse with the protoloph. There are no centrolophs. The protoloph and the metaloph may be connected forming an X-shape (2 out of 3) or a Y-shape (2 out of 4) near the lingual part. The metaloph and the posteroloph may be connected on the labial side (1 out of 4), or disconnected (3 out of 4). The posteroloph may be short (3 out of 4) or medium-long (1 out of 4). The specimens found in MAB 3 fit in this desciption. In BC1 the anteroloph may be isolated on the labial side and in one specimen the protoloph and the metaloph are joined on the lingual side. In MAB 0B the anteroloph is isolated on the lingual side. In one individual of each of the sites MAB 5, MAB 11 and CBR 0B, the anteroloph is isolated on the labial side. In one specimen of MAB 11 the posterior part is less reduced. In CBR 0B there is a small postcentroloph, the protoloph and the metaloph merge on the lingual side and the metaloph has an anterior spur.
REMARKS
This genus was defined to differentiate the more hypsodont, simple species with smaller third molars and premolars of the genus Pseudodryomys from the more brachyodont and more complex teeth ( García-Paredes et al. 2009), although the uniformity of the genus Pseudodryomys has previously been questioned ( Hugueney et al. 1978; Daams 1989, 1999a; Martín-Suárez et al. 1993; Daams & De Bruijn 1995). This genus occurs in Portugal, Spain, France, Switzerland and Germany from the Early to Middle Miocene ( García-Paredes et al. 2009).
The stratigraphic range of S. simplicidens extends from the Early Miocene (MN2) to the Middle Miocene (MN5) ( García-Paredes et al. 2009; Prieto et al. 2018; 2019). This species was described by De Bruijn (1966) based on the simplest material of the genus Pseudodryomys from the Calatayud-Montalbán Basin; later García-Paredes et al. (2009) described the new genus Simplomys to include this species.
The material from the Ribesalbes-Alcora Basin is characterized by a relatively long centrolophid and a higher percentage of specimens without postcentroloph ( Daams 1974; Daams et al. 1987; García-Paredes et al. 2009). This species was already described by Agustí et al. (1988) at the localities of Araya and Mas de Antolino 1. Metrically, they are within the variability observed in the deposits of zone C, with only a slightly narrower M 1 in MAB 5 ( Daams 1974; Daams et al. 1987; García-Paredes et al. 2009). The m3 variability surpasses that described by García-Paredes et al. (2009), ranging from specimens with minimal mesolophid reduction, as in the oldest deposits described by these authors, to others with a short mesolophid and a wide posterior valley. In the Early Miocene deposits of the Iberian Peninsula, it is a very abundant taxon; nevertheless, although occurring in many sites, it is certainly not abundant in the Ribesalbes-Alcora Basin.
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