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| Morphology | Ecology and taphonomy | External Literature Search | Age range and collections |
Taxonomy
Ensidelphis riveroi was named by Bianucci et al. (2020). Its type specimen is MUSM 3898, a skull (almost complete and well- preserved cranium (only small portions of both antorbital processes and both the jugals are missing) with articulated, complete mandib), and it is a 3D body fossil. Its type locality is Zamaca, which is in a Burdigalian coastal horizon in the Chilcatay Formation of Peru. It is the type species of Ensidelphis.
Synonymy list
| Year | Name and author |
|---|---|
| 2020 | Ensidelphis riveroi Bianucci et al. p. 7 figs. Figures 2–9, Tables 1–2 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Ensidelphis riveroi Bianucci et al. 2020
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| G. Bianucci et al. 2020 | Ensidelphis is a small odontocete having a narrow and very elongated rostrum (about 80% of the CBL) bearing about 64 small single-rooted teeth in each quadrant. It differs from all other odontocetes in having a protuberance (‘temporal swelling’, new term) on the lateral surface of the temporal fossa dorsal to the squamosal-parietal suture. It is referred to the Platanistoidea as defined above by having: Elongated hamular fossa of the pterygoid sinus extending anteriorly on the palatal surface of the rostrum; neurocranium shorter than wide (ratio < 0.90); and elongated anterior spine on the tympanic bulla associated with a marked anterolateral convexity. It differs from all other Platanistoidea in having a lesser posterior extension of both right and left ascending processes of the premaxillae, ending at the contact with the anterolateral angles of the nasals, and in having an even more elongated anterior spine of the tympanic bulla. It differs from all other Platanistoidea, with the exception of Platanista, for the lesser minimal distance between the temporal crests (see quantification below; character possibly related to the temporal swelling mentioned above). It differs from the similarly hyper-longirostrine Allodelphinidae in having the dorsal opening of the mesorostral groove anterior to the rostrum base narrower than the premaxilla, the lateral rostral suture between premaxilla and maxilla not deeply grooved, proportionally wider premaxillae at rostrum base (>60% of the width of the rostrum), and vertex not strongly transversely pinched. Ensidelphis belongs to the Platanidelphidi clade in having: Asymmetry of the premaxillae on the rostrum at some distance anterior to the premaxillary foramina, with the right premaxilla distinctly narrower than the left in dorsal view; posterior dorsal infraorbital foramen located along the vertex, more medial than the lateralmost margin of the premaxilla in the cranium; vertex distinctly shifted to the left compared to the sagittal plane of the skull; thick zygomatic process of the squamosal (ratio between the maximum distance from the anteroventral margin of the zygomatic process to the posterodorsal margin, in lateral view, and the vertical distance from the lower margin of the occipital condyles to the vertex of the skull > 0.35); and ventral edge of zygomatic process of squamosal in lateral view almost straight. Within the Platanidelphidi, Ensidelphis differs from Platanista, Pomatodelphis, and Zarhachis in the lateral rostral suture between premaxilla and maxilla being not deeply grooved; from Huaridelphis, Notocetus, and Squalodelphis in the presence of a deep lateral groove on the mandible; from Phocageneus, Notocetus, and Squalodelphis in the ventral groove of the tympanic not affecting the whole length of the bone, including the anterior spine; from Araeodelphis, Dilophodelphis, Furcacetus, Huaridelphis, Platanista, and Squalodelphis in the very elongated rostrum (>70% of the CBL); from Furcacetus, Huaridelphis, Macrosqualodelphis, and Notocetus in the smaller size of teeth at rostrum mid- length (diameter <2% of BZW); from Platanista, Pomatodelphis, and Zarhachis in the less elongated mandibular symphysis (61% of the total mandibular length contra >65%) and a consequent smaller angle between the mandibular rami (25° contra roughly 60°). |
Measurements
No measurements are available
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| Source: subo = suborder, o = order | |||||
| Reference: Uhen 2004 | |||||
Age range: Burdigalian or 20.45000 to 15.98000 Ma
Collections: one only
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Burdigalian | Peru (Ica) | Ensidelphis riveroi (type locality: 100330) |