Primitive synapsids were traditionally called "mammal-like reptiles" or "pelycosaurs", but both are now seen as outdated and disfavored paraphyletic terms, since they were not reptiles, nor part of reptile lineage. The modern term for these is "stem mammals", and sometimes "protomammals" or "paramammals".

The Hall of Primitive Mammals, one of two halls in the Lila Acheson Wallace Wing of Mammals and Their Extinct Relatives, traces the lower branches of the evolutionary tree of mammals, including monotremes, marsupials, sloths, and armadillos. The roots of the mammalian line reach back almost 300 million years.

We often hear monotremes called primitive mammals. This really is inaccurate because monotremes are mosaics of both primitive and derived traits. Primitive Characters - Cloaca, which is still present in other tetrapod groups. - Skull characters - still possess pre- and post-frontal bones. - no auditory bulla - lacrimal bones absent

2013年11月14日 · Mammals may be Earth’s most highly evolved animals but not all mammals are all that highly evolved. Some, like the 7 featured below, are downright primitive. Platypus (images via: Klaus) The...

1973年1月1日 · Various types of heat loss have been described as being more primitive than others, and certain mechanisms are described as characteristic of primitive mammals (Johansen, 1962; Robinson and Morrison, 1957; Hammel, 1968). In view of this it is perhaps better to discuss the mechanisms initially, and then examine the overall pattern of heat ...

2024年11月25日 · The most primitive mammals, direct descendants of therapsids, were members of the subclass Prototheria. Most prototherians were small and resembled modern shrews. All primitive animals laid eggs, just like their therapsid ancestors. The only remaining primitive animals today are the monotremes, which include the platypus and the echidna.

Condylarthra represented the primitive ungulates and structurally formed a sort of connect­ing link between the hoofed and clawed mammals. The cranial portion was located behind the orbit. Teeth were suited for herbivorous habit. Molars were low crown­ed. Amblypoda was short footed and hoofed forms of almost elephantine size. Fate of Archaic ...

The prosimians have retained the primitive mammalian condition of a bicornuate uterus, with two separate uterus chambers. In the simians, the uterus chambers have fused, an otherwise rare condition among mammals. Prosimians usually have litters rather than single offspring, which is the norm in higher primates. [12]

1973年12月31日 · In 1973 I reviewed the thermoregulation of those groups of mammals that retain archaic or conservative characteristics, the so-called primitive mammals (Orders: Monotremata, Marsupiala ...

Primates is an order of mammals, which is further divided into the strepsirrhines, which include lemurs, galagos, and lorisids; and the haplorhines, which include tarsiers and simians (monkeys and apes).Primates arose 74–63 million years ago first from small terrestrial mammals, which adapted for life in tropical forests: many primate characteristics represent adaptations to …