Pseudobolodon was a relatively early member of the also extinct order of mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s, Multituberculata

Multituberculata

The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

. It lived in Portugal

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

 during the Upper Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

, part of the "age of the dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s." It lies within the suborder "Plagiaulacida

Plagiaulacida

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs"...

" and family Paulchoffatiidae

Paulchoffatiidae

Paulchoffatiidae is a family of extinct mammals that lived predominantly during the Upper Jurassic period, though a couple of genera are known from the earliest Cretaceous. Some undescribed fossils from the Middle Jurassic of England may represent earlier versions. Remains have been reported from...

.

The genus Pseudobolodon ("false Bolodon") was named by Hahn G. in 1977 based on two species. A third one-time species, P. robustus (Hahn, 1978), seems to have transformed into Meketibolodon

Meketibolodon

Meketibolodon is a genus of extinct mammal from the Kimmeridgian Camadas de Guimarota of Guimarota, Portugal. It was a relatively early member of the also extinct order Multituberculata, suborder Plagiaulacida, family Paulchoffatiidae. The genus was named by Hahn G...

 robustus (Hahn G. 1978).

The species Pseudobolodon krebsi was named by Hahn G. & Hahn R. in 1994. Fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 remains consisting of two upper jaws have been found in the Kimmeridgian (Upper Jurassic)-age strata

Stratum

In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...

 of Guimarota

Guimarota

Guimarota is a disused coal mine that contains a diverse array of fossil animals and plants from the Upper Jurassic, Kimmeridgian period. It is located in central Portugal, near the city of Leiria....

, Portugal. As for the septomaxilla mentioned in the title of the reference: "A small, triangular bone is placed between the premaxilla and the maxilla; this bone is interpreted as a septomaxilla. This is a bone that is typical for lower tetrapods (amphibians, reptiles), but is usually absent in mammals", (Hahn & Hahn 2000, p.98). The premaxilla is the front bit of your upper jaw, while the maxilla is the side of it. Like other existing mammals, humans don't have this septomaxilla.

The species Pseudobolodon oreas was named by Hahn G. in 1977. Remains consisting of seven upper jaws have been found in Kimmeridgian (Upper Jurassic)-age strata of Guimarota, Portugal.