Crusafontia amoae, Cuenca-Bescós & Badiola & Canudo & Gasca & Moreno-Azanza, 2011

Cuenca-Bescós, Gloria, Badiola, Ainara, Canudo, José I., Gasca, José M. & Moreno-Azanza, Miguel, 2011, New dryolestidan mammal from the Hauterivian-Barremian transition of the Iberian Peninsula, Acta Palaeontologica Polonica 56 (2), pp. 257-267 : 260-262

Crusafontia amoae sp. nov.

Fig. 3 .

Etymology: The name is dedicated to our late colleague Olga Amo, who studied the vertebrate eggshells remains of the site CC2.

Holotype: Upper left molar MPZ CC2−1 .

Type locality and horizon: Cuesta Corrales 2, Terminal Hauterivianbasal Barremian.

Stratigraphic and geographic range.—Terminal Hauterivian –early Barremian, Galve, Teruel, Spain.

Material.— Two upper molars: the holotype, one upper left molar, MPZ CC2−1 , probably M4 or M5, described here. One upper right molar, MPZ Galve P−2 H4, from the site of Pelejón 2, probably M6 or M7, collected by José M. Herrero; described as Crusafontia cuencana and figured in Krebs (1993: fig. 2). Both sites lie in the upper part of the El Castellar Formation ( Fig. 2 ). Here we tentatively assign the doi:10.4202/app.2009.0157

lower molar MPZ Galve Y H2 described as Crusafontia cuencana and figured in Krebs (1993: fig. 6). The “Y” site is probably the Yacimiento Herrero site, in the lowermost part of the Camarillas Formation, early Barremian ( Fig. 2 ). The discussion (below) of the upper molar described by Krebs (1993) is based solely on his descriptions.

Diagnosis.—Large−sized species of Crusafontia with upper molars characterized by their mesio−labially enlarged parasyle with a large mesial wear facet that runs from the tip of the stylocone to the base of the parastyle, the ample ectoflexus on their labial border, their continuous metacrista with a deep notch, and the pointed mesio−lingual slope of the paracone.

Differential diagnosis.— Crusafontia amoae sp. nov. differs from Crusafontia cuencana by its larger size, the high, mesially protruding and rounded parastyle (as in Comotherium ) in relation to the stylocone, the larger mesial wear facet, the pointed and more lingually placed slope of the paracone (as in Comotherium , unlike Crusafontia cuencana and other Dryolestida ) directed to the mesio−lingual corner, the wider ectoflexus (as a measure of the distance between the stylocone and the metastyle), the presence of cusp C, the larger and distinct metacone, and the presence of a notch in the metacrista in distal view. As in Comotherium richi and Crusafontia cuencana , no cusps or ridges are found in the trigon basin, unlike other Dryolestida .

Description.—MPZ CC2−1 is an upper left molar (L, 0.98; W, 1.11; H, 0.91), probably a M4 or M 5 in position in view of its well−developed parastylar region. We rule out the possibility of it being a premolar or a deciduous tooth because it is enlarged labio−lingually and because of the presence of a lingual root (though broken). The molar is triangular in occlusal view, with rounded corners and with a narrower, pointed lingual part ( Fig. 3A ). There is a conspicuous medial indentation or ectoflexus on the labial face. The lingual side is dominated by a lofty paracone, which is the highest cusp of the tooth ( Fig. 3B, D, E ). On the labial side there are three cusps: from mesial to distal, the parastyle, stylocone, and metastyle ( Fig. 3C ). There is a tiny cusp “C” in the distolabial corner. In the posterior crest, or metacrista, a distinct metacone is separated from the paracone by a notch, a character best displayed in distal view ( Fig. 3D ). The parastyle is large, and slightly less elevated compared with the stylocone; the parastylar region is enlarged, forming a parastylar wing. There are two transversal crests, the paracrista and the metacrista. The paracrista joins the paracone with the stylocone. The metacrista joins the paracone, metacone and cusp “C”. In the trigon basin there are no traces of a median stylar cusp and median ridge, nor is there a swelling in the middle; on the contrary, its bottom is uniformly basined.

Upper right molar MPZ Galve P−2 H4, probably M6 or M7, described by Krebs (1993: 238–241, fig. 2). It is similar, in its size and heart−shaped morphology in occlusal view ( Fig. 4 ), to the molar from CC 2. The ample ectoflexus that separates the stylocone and the metastyle is similar in the two teeth, especially when viewed in labial view ( Fig. 3C and Krebs 1993: fig. 2).

Figures

Fig. 3. Dryolestidan mammal Crusafontia amoae sp. nov., MPZ CC2−1 M4 or M5, holotype, from the site of Cuesta Corrales 2, Colladico Blanco level, El Castellar Formation, Galve, Teruel, Spain in, occlusal (A), mesial (B), labial (C), distal (D), and lingual (E) views. The schematic drawing of C. amoae, in the box in the lower left−hand corner shows the main anatomical elements of the occlusal surface of a dryolestidan.

Fig. 2. Geological setting of the Mesozoic mammal fossil sites from the Galve area. Stratigraphy of the Wealden facies and geological mapping of the Galve syncline (modified from Díaz Molina and Yébenes 1987).

Fig. 4. Drawings of Dryolestida left upper−molar, modified from the original descriptions. A–C, Kimmeridgian; D–F, Tithonian–Berriasian; G–H, early Barremian; I, late Barremian. A. Left M4 or M5 of Comotherium richi Prothero, 1981, from the Upper Jurassic Morrison Formation, Como Bluff locality, Wyoming, USA. B. Right M5, reversed, of Dryolestes leiriensis Martin, 1999, from Guimarota, Portugal. C. Left M6 of Krebsotherium lusitanicum Martin, 1999, from Guimarota, Portugal. D. Right M4 or M 6 (reversed) of Portopinheirodon asymmetricus Martin, 1999, Porto Pinheiro, Lourinha, Portugal. E. Right M5 (reversed) of Laolestes andresi Martin, 1999, from Porto Pinheiro, Lourinha, Portugal. F. Right upper molar of Donodon perscriptoris Sigogneau−Russell, 1991, Anoual, Morocco. G. Left M4 or M 5 of Crusafontia amoae sp. nov., holotype, Cuesta Corrales 2, El Castellar Formation, Galve, Teruel, Spain. H. Right M6 or M 7 (reversed) of Crusafontia amoae sp. nov., first described as upper molar of Crusafontia cuencana by Krebs (1993), P−2 H4 Pelejón 2, Galve, Teruel, Spain. I. Left M2 or M3, of Crusafontia cuencana Henkel and Krebs, 1969, Uña, La Huérguina Formation, Cuenca, Spain, (from Krebs 1993). Scale bars 1 mm.