Which of the following is the correct dental formula of the primitive Eutherian mammal?

Which of the following is the correct dental formula of the primitive Eutherian mammal?

The formula for primitive eutherians is I3/3 C1/1 P4/4 M3/3 = 44 teeth; that for primitive marsupials is I5/4 C1/1 P3/3 M4/4 = 50 teeth.

What is the formula for dentition?

The permanent dentition consists of 32 teeth in total, with the dental formula 2123/2123, indicating two incisors, one canine, two premolars, and three molars in each quadrant. Specific teeth can be denoted in several different ways, the most common of which is the Universal Tooth Numbering System (Figure 2.37).

What is the deciduous dental formula?

In humans, the deciduous dentition consists of 20 total teeth, with the dental formula 2102 (or 2102/2102), indicating two incisors, one canine, zero premolars, and two molars in each quadrant.

What is mammalian dentition?

The arrangement of teeth in the upper and lower jaws, mainly on the premaxilla, maxilla and dentary bones, is called dentition. Absence of teeth: Teeth are present in all mammals though a secondary toothless condition is found in some mammals.

Is the Eomaia an eutherian or placental mammal?

Although the fossil’s skull is squashed flat, its teeth, tiny foot bones, cartilages and even its fur are visible. While possessing a number of eutherian features, Eomaia is not a true placental mammal as it lacks some features that are specific to placentals.

How are eutherians related to all other mammals?

In cladistics, Eutheria is the total group of placental mammals: that is, all mammals more closely related to placentals than any other mammals. However, early eutherians seem not to have been placentals at all, as they possessed abone, the prebubic bone, also found in marsupials, that meant there was no room for a placenta.

Where was the first eutherian mammal ever found?

Range: Daxigou site, Jianchang, from the Tiaojishan Formation; Callovian/Bathonian of western Liaoning, China. Comments: The earliest eutherian mammal, known from an articulated and nearly complete skeleton including incomplete skull preserved with full dentition.