Mus cf. musculus Linnaeus, 1758

Marquina-Blasco, Rafael, Fagoaga, Ana, Crespo, Vicente D., Martínez-Ortí, Alberto, Bailon, Salvador, Sánchez-Marco, Antonio, Gracia-Monferrer, Daniel, Santisteban, Carlos de & Ruiz-Sánchez, Francisco Javier, 2023, Squamates, rodents, and birds from Holocene deposits of the Illa Grossa Island (Columbretes Islands, Castellón, Spain): an unexpected diverse assemblage, Comptes Rendus Palevol 22 (18), pp. 409-438 : 419-420

Mus cf. musculus Linnaeus, 1758

( Fig. 5)

Mus musculus Linnaeus,1758: 62 (original description of the species).

Mus domesticus Rutty, 1772: 281 .

Mus abbotti Watherhouse, 1837: 77 .

Mus nordmanni – Keyserling & Blasius 1840: 330 (nomen nudum).

Mus molossinus Temminck, 1845: 51 .

Mus varius – Fitzinger 1867: 70 (nomen nudum).

Mus musculus yonakuni Kuroda, 1924: 8 . — Kaneko & Maeda 2002: 12.

Mus albula Kishida, 1924: 143 . — Kaneko & Maeda 2002: 12.

Mus bactrianus tantillus Allen, 1927: 9 . — Schwarz & Schwarz 1943: 62 (reviewed along with the rest of the genus). — Ellerman & Morrizon-Scott 1951: 607.

MATERIAL EXAMINED. — 3 I ( COLT-33 to COLT-35 ); 1 M 1 ( COLT-30 ); 1 M2 ( COLT-29 ); 2 m 1 ( COLT-28, COLT-31 ); 1 m 2 ( COLT-32 ) .

DESCRIPTION

Upper incisors are rounded and curved.

The recovered first upper molars are brachyodont and bunodont, and do not present the t7. The t1 is placed towards the posterior part of the tooth.

The first lower molars are brachyodont and bunodont and there is no anterocentral tubercle. On the anterior region, the tE is not well individualized, and it develops a trilobed morphology in one specimen (COLT-31). COLT-28 has its tE broken, while COLT-37 is quite worn. No external cingular margin with a well-developed secondary cusp (c1), is present in any of the three specimens.

The second molars are also brachyodont and bunodont, with no trace of the antero-labial tubercle. The labial cingulum is not developed, and the posterior tubercle is big, round or oval.

REMARKS

The absence of the t7 tubercle in the upper first molars is characteristic of the genus Mus , contrary to what it is seen in the genus Apodemus Kaup, 1829 , in which the t7 is always present ( Chaline 1974). Moreover, the first lower molars recovered from in Columbretes lack the anterocentral tubercle, as it is the case in Mus ( Pasquier 1974; Gosàlbez 1987). The trilobed morphology observed in the anterior part of the first lower molars is characteristic of Mus musculus ( Darviche & Orsini 1982) . In addition, the clear absence of an external cingular margin with a well-developed secondary cusp in the first lower molars also points to M. musculus , whereas it is quite common in Mus spretus Lataste, 1833 ( Darviche & Orsini 1982; Darviche et al. 2006). Regarding the metrics of the first lower molars, the mean length and width values fall between Mus spretus lowest mean values ( Fig. 6A), although if we take into account specimens values, those are placed in an overlapping area between both species values ( Fig. 6B) ( Darviche & Orsini 1982; Domínguez García et al. 2019).

Species within the genus Mus can be distinguished based on morphotypes percentages. Unfortunately, the very low population size does not allow us to extract percentages. However, all morphologic characters are typical of Mus musculus . On the other hand, metric values are compatible with some big individuals from a Mus musculus population as shown in the record ( Darviche & Orsini 1982). Due to the aforementioned reasons, we ascribe the studied mammal material to Mus cf. musculus .