Desmanodon daamsi Van den Hoek Ostende, 1997

Van Den Hoek Ostende, Lars W., Casanovas-Vilar, Isaac & Furió, Marc, 2020, Stuck in the middle. A geographical appraisal of the oldest insectivores - and a marsupial - from the Vallès-Penedès Basin (early Miocene, Catalonia, Spain), Comptes Rendus Palevol 19 (1), pp. 1-25 : 10-12

Desmanodon daamsi Van den Hoek Ostende, 1997

( Fig. 4 A-F)

MATERIAL AND MEASUREMENTS (in cm). — Spain. El Palau 3B, 1 m 2 dext., IPS86232 , – × –; Can Martí Vell III, 1 m 3 sin., IPS86278 , 1.24 × 0.78 ; Sant Andreu de la Barca 3, 1 M3 sin., IPS86203 , 1.12 × 1.67; Sant Andreu de la Barca 1, 1 P? dext., IPS86195 , 1.45 × 0.69; 2 P4 dext., IPS86192-93 , 1.43 × 1.17; – × –; 2 M1 sin., IPS86183 - 84, – × –; 1.62 × 1.50; 1 M2 dext., IPS86181 , 1.77 × 2.25 ; Turó de les Forques , 1 P4 dext., IPS85483 , 1.36 × 1.24; 1 damaged M1 dext., IPS85488 , – × –; 1 M1 sin., IPS86816 , 1.73 × 2.32; 1 M2 sin., IPS86817 , 1.74 × 1.97; 1 M2 dext., IPS86818 , 1.76 × 2.13 ; Costablanca , 1 M2 sin., IPS19372 , 1.91 × 1.84 .

DESCRIPTION

P?

One premolar from Sant Andreu de la Barca 1 is tentatively assigned to Desmanodon based on its high tip. The occlusal outline is teardrop-shaped, with the point directed backwards. The tip of this unicuspid lies in the front part of the premolar at about two thirds its length. It bears a sharp posterocrista and has a round anterior face. A narrow cingulum surrounds the tooth, being interrupted at the anterolabial flank of the paracone only. The cingulum is a bit thicker at the posterior end of the premolar.There are two plank-shaped roots of about equal size, which stand parallel to one another.

P4

The outline of the occlusal surface is triangular; the premolar is somewhat longer than wide. Both parastyle and protocone are small, the posterocrista is S-curved (Morphotype C sensu Van den Hoek Ostende 1989). The paracone is high and its posterocrista is curved just behind its tip. The narrow cingulum is continuous on the lingual side, interrupted at the base of the paracone on the labial side.

M1

The labial cusps, and particularly the metacone, are very high. The occlusal surface is irregularly quadrangular, with a long lingual side. The posterior arm of the paracone is relatively straight. The posterior arm of the metacone is just somewhat longer than the anterior arm. The mesostyle is incompletely divided. There is a small, slightly protruding parastyle in the anterolabial corner of the molar. The low protocone lies in the anterolingual corner of the molar. Its short anterior arm ends against the base of the paracone. The posterior arm follows the contours of the outline lingually, and continues as the well-developed posterior cingulum. In one of the two specimens from Turó de les Forques, a slight thickening in the posterior arm reveals the position of the hypocone. There is no protoconule. In one of the two specimens, there is a very short portion of lingual cingulum just behind the protocone.

M2

It is slightly asymmetrical due to the anterior position of the protocone and the small hypocone. There is no protoconule. The high labial cusps occupy about two thirds of the occlusal surface. The mesostyle is poorly divided. The small parastyle is slightly protruding; the metastyle is more developed as a labial thickening of the posterior cingulum. There are short stretches of cingulum along the anterior flank of the paracone and the posterior flank of the metacone, respectively.

M3

It has an incompletely divided mesostyle, with the two cusplets clearly separated in the unworn specimen from Sant Andreu de la Barca 3. The anterior arm of the protocone is only slightly longer than the posterior arm, and bends sharply at its end to form a protruding parastyle. There is a short stretch of cingulum between the parastyle and the anterior flank of the paracone. The hypocone is a small but distinct cusp, well isolated from the metacone.

m2

The specimen from El Palau 3B has been restored after breakage. The trigonid is somewhat narrower and clearly shorter than the talonid. The cuspids are very high. The oblique cristid ends against the posterior wall of the trigonid, just labially to the metaconid. The entocristid is high, and quickly slopes down. The cingulid is well developed on the anterior and posterior sides. The lingual cingulid cannot be assessed properly because of the damage, but is certainly narrower than the anterior and posterior cingulids. The entostylid protrudes sharply.

m3

It has a talonid which is only slightly reduced and somewhat shorter and narrower than the trigonid. The two arms of the protoconid form a narrow V-shape. The oblique cristid ends halfway the posterior wall of the trigonid. The entocristid is well developed. The anterior cingulid is narrow but distinct and rounds the paraconid, ending below the trigonid valley.

REMARKS

The early history of the genus Desmanodon mirrors that of Galerix . This talpid also had its oldest known records in Anatolia and it purportedly dispersed into Europe around the MN2/ MN3 transition ( Van den Hoek Ostende 1997; Van den Hoek Ostende et al. 2016). The only species known so far from the Iberian Peninsula is D. daamsi , which is characterized by an incompletely divided mesostyle in the upper molars and poor hypocone development on the M1 and M2. In these characters, as well as in size, the material from the Vallès-Penedès fits well with the earlier described assemblages from the basins of Calatayud-Teruel, Rubielos de Mora, and Ribesalbes-Alcora ( Van den Hoek Ostende 1997, 2003; Hordijk et al. 2015; Van den Hoek Ostende et al. 2017; Crespo-Roures et al. 2019). The most characteristic feature of the Iberian talpid, its relatively slender humerus, could not be ascertained for in the Vallès-Penedès assemblages as to date no humeri have been found.