Patriarchus icochiloides Ameghino, 1894a

Fernández, Mercedes, Fernicola, Juan Carlos, Cerdeño, Esperanza & Reguero, Marcelo A., 2018, Identification of type materials of the species of Protypotherium Ameghino, 1885 and Patriarchus Ameghino, 1889 (Notoungulata: Interatheriidae) erected by Florentino Ameghino, Zootaxa 4387 (3), pp. 473-498 : 493-494

Patriarchus icochiloides Ameghino, 1894a

Holotype. MACN-A 4021 ( Fig. 4 E ), right maxillary fragment with alveolus of P1 and series P2–M3, and MACN- A 4022 ( Fig. 4 F ), right mandibular fragment with alveoli of p2–3 and series p4–m3, both of the same individual.

Diagnosis ( Ameghino 1894a: 14–15). “ Cette espèce forme le passage au genre Icochilus . Les molaires et prémolaires sont égales à celles du genre Protypotherium , mais la mandibule est robuste, avec la branche horizontale massive, courte, basse en avant et très haute en arrière comme dans le genre lcochilus. Les séries dentaires supérieures sont fortement arquées. Longueur des sept molaires inférieures, 33 mm. Hauteur de la mandibule: en dessous de la 2 p. 11 mm.; en dessous de la partie antérieure de la 3 m. 21 mm ”

English translation. This species represents the passage to the Genus Icochilus . Molars and premolars are equal to those of the genus Protypotherium , but the mandible is robust, with short, massive horizontal ramus, anteriorly low and posteriorly very high as in the Genus Icochilus . The upper tooth row is strongly arched. Length of the seven lower cheek teeth, 33 mm. Height of the mandible: below p2, 11 mm; below the anterior region of m3, 21 mm.

Comments. Ameghino (1894a) did not illustrate any specimen of this species. According to Ameghino’s catalogue, the maxillary fragment MACN-A 4021 and the mandibular fragment MACN-A 4022, both of the same individual, are the type materials of this taxon. Instead, Mones (1986) only indicated the former as the type specimen. The upper teeth series of MACN-A 4021 are strongly arched as described by Ameghino (1894a). MACN-A 4022 also matches the original diagnosis ( Ameghino 1894a) because, in addition to the typical morphology of lower cheek teeth observed in other species of Protypotherium (see P. antiquum for some general characteristics), the mandible is robust with short and strong horizontal ramus that increases its height backwards, and the measurements available to be taken (length of p2–m3 = 31.2 mm; height of the mandibular ramus below p2 = 10.81 mm; height of the mandibular ramus below the mesial region of m3 = 21.6 mm) are consistent with those provided by Ameghino (1894a). Regarding the remaining eight specimens assigned to the species in Ameghino’s catalogue, all of them are mandibular fragments (e.g., MACN-A 4026, MACN-A 4027, MACN-A 4028, MACN-A 9655 and MACN-A 9656) and even the measurements that can be taken (height of the mandibular ramus below p2 = 14 mm in MACN-A 4023, height of the mandibular ramus below m3 = 17.87 mm in MACN-A 4024, 18.43 mm in MACN-A 4025 and 18.90 mm in MACN-A 4028) are not consistent with the type specimen, which leads to discard these materials as types. Consequently, the individual MACN-A 4021 plus MACN-A 4022 is confirmed as the holotype of Pa. icochiloides .

Chronological and geographical distribution of the type specimen. Santacrucian SALMA, Santa Cruz Province.

Figures

FIGURE 4. Patriarchus leptocephalus, holotype MACN-A 3989, incomplete skull, in ventral (A) and dorsal (B) views. Patriarchus altus, holotype MACN-A 4001, incomplete skull, in ventral (C) and dorsal (D) views. Patriarchus icochiloides, holotype MACN-A 4021, right maxillary fragment with alveolus of P1 and P2–M3, in occlusal view (E); holotype MACN-A 4022, right mandibular fragment with alveoli of p2–3 and p4–m3, in occlusal view (F). Scale bar = 10 mm.