Microdyromys koenigswaldi De Bruijn 1966
Creators: name: Crespo, Vicente Daniel
name: Ríos, María
name: Marquina-Blasco, Rafael
name: Montoya, Plini
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Gliridae
Microdyromys
Microdyromys koenigswaldi

description: Microdyromys koenigswaldi De Bruijn, 1966
(Fig. 3 AE-AI)
LOCALITIES. — BC1 and FS1.
MATERIAL. — BC1: 1 M2, 1 M3; FS1: 1 p4, 1 m 1, 1 M2, 1 M3.
MEASUREMENTS. — Appendix 3
DESCRIPTION
p4 (FS1)
The tooth is subtriangular in occlusal view with high crestids and narrow valleys.The anterolophid is short. The metalophid is short and semicircular. The mesolophid and the posterolophid are long, curved and connected. The posterotropid is well developed.
m1 (FS1)
An elongated tooth with a rectangular outline in occlusal view,with narrow valleys and straight and wide crestids. The anterolophid is short. There is a small anterotropid. The metalophid is long and connected to the endolophid.The centrolophid is long.The mesolophid and the posterolophid are long and well connected in the lingual side. There is a well-developed posterotropid. The labial cuspids are better developed than the lingual ones.
M2 (BC1)
Tooth subcuadrangular in occlusal view. The anteroloph is relatively short. The endoloph is complete. The protoloph and the metaloph are independent. The prototrope is long and well developed. The precentroloph is longer than half of the tooth width, and almost reaches the lingual side. The postcentroloph is long. The posteroloph is short and disconnected in the labial side. The posterotrope is small. The labial cuspids are better developed than the lingual ones. The lingual ornamentation is poorly developed. In the FS 1 specimen there is an anterotrope and the prototrope is shorter than in the BC1 material.
M3 (BC1)
The shape of the tooth is subrectangular in occlusal view. The anteroloph is long and forms a closed ellipse with the protoloph. The precentroloph is short and the postcentroloph is long; some small crests are independent and others are connected to the protoloph, thus yielding a chaotic appearance. The protoloph and the metaloph are not connected in the lingual side and form a U-shaped crest. The metaloph is very short and connected with the posteroloph in the middle of the tooth forming an ellipse. The posteroloph is long. The FS1 material is characterized by an anteroloph and a shorter posteroloph isolated in the lingual side.
REMARKS
Microdyromys koenigswaldi is the scarcer species of this genus represented in the Ribesalbes-Alcora Basin. As discussed later, it was probably linked to drier environments. Compared to other species of the genus, M. koenigswaldi is larger in size, shows better-developed accessory crests, and some specimens present an anterotrope, which is rather unusual in Microdyromys.
After Vianey-Liaud (2003), and following the classification of Daams (1981), the upper molars mainly belong to morphotype H, although, unlike M. legidensis, morphotype K is also present, with an extra crest out of the trigone. On the other hand, the lower molars belong to morphotype 3. The distinction between M. legidensis and M. koenigswaldi is under discussion (e.g. Hordijk et al. 2015), and both species have often been recorded together (e.g. Van der Meulen et al. 2012). However, the sites studied here provide enough diagnostic characteristics to distinguish them.
The biometric data show that the material from the Ribesalbes-Alcora Basin is similar in size to the one recovered in the site Vargas 1A, though with slightly larger upper molars, also like M. aff. koenigswaldi from Blanquatère and M. koenigswaldi from Bouzigues 2, Erkertshofen 2, Valdemoros 1A, 3B and 3E (De Bruijn 1966; Daams 1981; Wu 1993; Aguilar et al. 1997; Aguilar & Lazzari 2006; García-Paredes et al. 2010), and larger than M. aff. koenigswaldi from Bouzigues (Aguilar 1974). In addition, the m1 is longer than in M. koenigswaldi from Cases de la Valenciana and Puente de Praga 92 (Hernández-Ballarín et al. 2017; Jovells-Vaqué et al. 2018), although the m1 from FS1 has the narrowest width described so far.
description: Published as part of Crespo, Vicente Daniel, Ríos, María, Marquina-Blasco, Rafael & Montoya, Plini, 2023, They are all over the place! The exceptional high biodiversity of dormice in the Early Miocene of the Ribesalbes-Alcora Basin (Spain), pp. 589-641 in Geodiversitas 45 (20) on page 595, DOI: 10.5252/geodiversitas2023v45a20, http://zenodo.org/record/10137206